Reduced dental calcium expression and dental mass in chronic sleep deprived rats: Combined EDS, TOF-SIMS, and micro-CT analysis

NASA Astrophysics Data System (ADS)

Kuo, Yi-Jie; Huang, Yung-Kai; Chou, Hsiu-Chu; Pai, Man-Hui; Lee, Ai-Wei; Mai, Fu-Der; Chang, Hung-Ming

2015-08-01

Teeth are the hardest tissue in the body. The growth of teeth is closely regulated by circadian rhythmicity. Considering that sleep deprivation (SD) is a severe condition that disrupts normal circadian rhythmicity, this study was conducted to determine whether calcium expression (the major element participating in teeth constitution), and dental mass would be significantly impaired following SD. Adolescent rats subjected to 3 weeks of SD were processed for energy dispersive spectrum (EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and micro-computed tomography (micro-CT) analyses. The EDS and TOF-SIMS results indicated that high calcium intensity was detected in both the upper and lower incisors of untreated rats. Micro-CT analysis corresponded closely with spectral data in which an enhanced dental mass was calculated in intact animals. However, following SD, both calcium expression and the dental mass were remarkably decreased to nearly half those of the untreated values. Because SD plays a detrimental role in impairing dental structure, establishing satisfactory sleep behavior would therefore serve as a crucial strategy for preventing or improving prevalent dental dysfunctions.

Increased Cell Proliferation and Gene Expression of Genes Related to Bone Remodeling, Cell Adhesion and Collagen Metabolism in the Periodontal Ligament of Unopposed Molars in Growing Rats

PubMed Central

Dorotheou, Domna; Farsadaki, Vassiliki; Bochaton-Piallat, Marie-Luce; Giannopoulou, Catherine; Halazonetis, Thanos D.; Kiliaridis, Stavros

2017-01-01

Tooth eruption, the process by which teeth emerge from within the alveolar bone into the oral cavity, is poorly understood. The post-emergent phase of tooth eruption continues throughout life, in particular, if teeth are not opposed by antagonists. The aim of the present study was to better understand the molecular processes underlying post-emergent tooth eruption. Toward this goal, we removed the crowns of the maxillary molars on one side of the mouth of 14 young rats and examined gene expression patterns in the periodontal ligaments (PDLs) of the ipsilateral and contralateral mandibular molars, 3 and 15 days later. Nine untreated rats served as controls. Expression of six genes, Adamts18, Ostn, P4ha3, Panx3, Pth1r, and Tnmd, was upregulated in unopposed molars relative to molars with antagonists. These genes function in osteoblast differentiation and proliferation, cell adhesion and collagen metabolism. Proliferation of PDL cells also increased following loss of the antagonist teeth. Interestingly, mutations in PTH1R have been linked to defects in the post-emergent phase of tooth eruption in humans. We conclude that post-emergent eruption of unopposed teeth is associated with gene expression patterns conducive to alveolar bone formation and PDL remodeling. PMID:28239357

[The effect of overdose fluoride on the expression of TGF-beta1 in rat's dental pulps].

PubMed

Wu, Yu; He, Ke-xing; Yang, Yi-ping; Cao, Yang; Liang, Zhi-feng

2006-04-01

To observe the effect of overdose fluoride on the expression of TGF-beta1 in rat's dental pulps. 20 wister rats were divided into two groups. In the control group, equal dose distilled water were given to the rats. In the experimental group, 20 mg.kg(-1).d(-1) NaF were given. After 8 weeks of treatment, immunohistochemical staining was adopted for detection of the expression of TGF-beta1 in dental pulps of the rats. SPSS10.0 software package was used for Student's t test. Image analysis results showed that the expression of TGF-beta1 in the dental pulp and inner dentin were inhibited in the experimental group as compared with the control group (P<0.01). The overdose fluoride will inhibit the secretion of TGF-beta1, which leads to abnormal development of the teeth.

[Interaction between fluorine and zinc after long-term oral administration into the digestive system of rats].

PubMed

Mazurek-Mochol, Małgorzata

2002-01-01

Drug interactions are the side effect of administration of two or more drugs or a drug-food combination. Although some drug interactions are intentional and beneficial to the patient, the majority are unintentional and associated with a potentially harmful effect. The aim of this study was to search for interactions in rats between fluoride and zinc administered orally for 12 weeks and to elucidate any potential toxicological and therapeutic consequences. 60 male Wistar rats were divided into six groups of ten rats each and exposed to: 1. controls (distilled water); 2. sodium fluoride (NaF); 3. low-dose zinc (Zn); 4. high-dose zinc; 5. NaF + low-dose Zn; 6. NaF + high-dose Zn. At the end of the experiment the content of F- and Zn+ in serum, urine, incisors, femur and mandible was measured and densitometry of femoral bones was performed. Serum alkaline phosphatase, alanine and aspartate aminotransferase activities, as well as bilirubin and creatinine concentrations were determined to confirm non-toxicity of fluoride dose. Animals receiving NaF only demonstrated higher content of fluorine in serum, urine bones and teeth. Zinc concentrations in serum, urine, bones and teeth were elevated in rats receiving zinc with or without NaF. Fluorine accumulation in bones and teeth was reduced by Zn, but in general the effect lacked statistical significance. Zinc slightly reduced the concentrations of fluorine in serum and urine. Sodium fluoride slightly reduced the concentration of zinc in serum and urine. Bone mineral content (BMC) was significantly increased by NaF and was not further increased by co-administration of zinc. No changes in serum alkaline phosphatase, alanine and aspartate aminotransferase activities, bilirubin and creatinine concentrations were detected. In conclusion, simultaneous administration of fluorine and zinc may be beneficial for prevention and treatment of pathologic conditions in bones and teeth and is not accompanied by an increase in fluorine levels which could be responsible for toxicological symptoms.

Histological evaluation of the pulp in teeth from dogs with naturally occurring periodontal disease.

PubMed

Nemec, Ana; Pavlica, Zlatko; Stiblar-Martincic, Draga; Petelin, Milan; Erzen, Damjan; Crossley, David

2007-12-01

The purpose of this investigation was to evaluate the pulp of dog teeth affected by advanced periodontal disease. Histological examination was done on demineralized teeth extracted during clinical treatment of mature, client owned small and medium-size breed dogs with either good periodontal health or with advanced naturally occurring periodontal disease. Routinely stained sections from 5 clinically normal teeth and 22 teeth with advanced periodontitis from dogs between 5 and 12-years of age were examined using light microscopy. The pulp cavities of most teeth were narrow with low cellularity and some fibrosis of the pulp. Findings specific to periodontally affected teeth included acute and chronic pulpitis, vascular congestion, and pulp necrosis. A glomus body was identified in the pulp of one tooth and areas of poorly mineralized cementum were seen in both normal and diseased teeth. Age related changes in dog teeth appear similar to those reported for man and the rat. In addition to age related changes, the pulp of dog teeth with advanced periodontal disease were frequently inflamed or necrotic. This may reflect the advanced periodontitis affecting these teeth or a mechanical effect related to excessive tooth mobility. Further study is required to determine the etiology and significance of these findings and to investigate pulp status in less severely diseased teeth.

Experiment K-310: The effect of spaceflight on osteogenesis and dentinogenesis in the mandibles of rats

NASA Technical Reports Server (NTRS)

Simmons, D. J.; Russell, J. E.; Winter, F.; Rosenberg, G. D.; Walker, W. V.

1981-01-01

Normal rates of dentinogenesis and osteogenesis in the body of the mandible were observed. The total calcium, inorganic phosphorus and hydroxyproline levels in the jaws and incisors of the flight rats were normal. Gravity density fractionation studies suggested, however, that spaceflight caused a delay in the normal maturation of bone mineral and matrix; normal values were reestablished by 6 days postflight. The teeth were spared. The circadian and ultradian patterns of dentin calcification were normal during spaceflight and recovery periods, but the enamel rhythms displayed a greater amplitude of sulfur concentrations and this abnormal calcium to sulfur ratios only during exposure to zero gravity. The rat mandible and teeth do not suffer the deficits of bone formation common to weight bearing parts of the skeleton during spaceflight. The only derangements detected were in the quality of the matrix and mineral moieties.

Effect of topical applications of neutral sodium fluoride on dental careis in the rat.

PubMed

Poulsen, S; Larson, R H

1975-01-01

A study on various regimens by which the same total amount of neutral sodium fluoride is applied to the teeth of rats showed that greater effects were observed after frequent application of 0.2% solutions than after less frequent application of more concentrated solutions.

The whitening effect of bleaching agents on tetracycline-stained rat teeth.

PubMed

Shin, D H; Summitt, J B

2002-01-01

This study compared the whitening effect of three bleaching agents on the teeth of rats and demonstrated differences in bleaching where dentin was exposed or enamel was thin. Thirty Albino rats were peritoneally injected with tetracycline solution daily for two weeks. Thirty-two disc-shaped specimens were cut from the crowns of incisors removed from sacrificed rats and were irradiated with UV light for 16 hours. Sections were stored in saline. Eight sections served as controls and were not bleached. Three bleaching agents (Opalescence, Rembrandt and Nite White) were applied to eight specimens each, five times a day for two weeks, and images of the sections were recorded at the following times: before bleaching (baseline), day 1, day 3, day 5, day 7, day 9, day 11 and day 14. Mean colors to demonstrate any change (deltaE) from baseline for each time period were as follows: control-9.78 (baseline), 9.17, 9.36, 9.65, 9.40, 9.99, 10.57, 11.36; Opalescence-10.08, (baseline) 7.63, 6.72, 6.04, 5.10, 4.87, 4.89, 4.27; Rembrandt-9.83 (baseline), 11.27, 9.55, 8.36, 7.75, 6.94, 7.11, 7.04; Nite White-10.44 (baseline), 9.92, 7.58, 6.80, 5.45, 5.05, 4.73, 4.01. All bleached teeth were lightened (p<.01). Another 56 tetracycline-stained rat incisors were UV irradiated for three days. Three different penetration depths were tested: penetration through lingual dentin and labial enamel (DN group), penetration through labial enamel only (RE group) and penetration through labial enamel covered with 1.0 mm human enamel (HE group). Specimens were bleached with Opalescence for one hour five times a day for one week or four weeks. A control group of unbleached teeth was also examined. Results (deltaE) were as follows: control--11.67; 1-week DN--13.55; 1-week RE--12.80; 1-week HE--12.07; 4-week DN--7.48; 4-week RE--7.50; 4-week HE--11.69. The color change in the 4-week DN and the 4-week RE groups showed the greatest reduction (p<.01).

Characterization of enamel caries lesions in rat molars using synchrotron X-ray microtomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Free, R. D.; DeRocher, K.; Stock, S. R.

Dental caries is a ubiquitous infectious disease with a nearly 100% lifetime prevalence. Rodent caries models are widely used to investigate the etiology, progression and potential prevention or treatment of the disease. To explore the suitability of these models for deeper investigations of intact surface zones during enamel caries, the structures of early-stage carious lesions in rats were characterized and compared with previous reports on white spot enamel lesions in humans. Synchrotron X-ray microcomputed tomography non-destructively mapped demineralization in carious rat molar specimens across a range of caries severity, identifying 52 lesions across the 30 teeth imaged. Of these lesions,more » 13 were shown to have intact surface zones. Depth profiles of fractional mineral density were qualitatively similar to lesions in human teeth. However, the thickness of the surface zone in the rat model ranges from 10 to 58 µm, and is therefore significantly thinner than in human enamel. These results indicate that a fraction of lesions in rat caries possess an intact surface zone and are qualitatively similar to human lesions at the micrometer scale. This suggests that rat caries models may be a suitable analog through which to investigate the structure of surface zone enamel and its role during dental caries.« less

Effect of iron containing supplements on rats' dental caries progression.

PubMed

Eshghi, Ar; Kowsari-Isfahan, R; Rezaiefar, M; Razavi, M; Zeighami, S

2012-01-01

Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children's diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen.

The Ovariectomized Rat as a Model for Studying Alveolar Bone Loss in Postmenopausal Women

PubMed Central

Johnston, Bryan D.; Ward, Wendy E.

2015-01-01

In postmenopausal women, reduced bone mineral density at the hip and spine is associated with an increased risk of tooth loss, possibly due to a loss of alveolar bone. In turn, having fewer natural teeth may lead to compromised food choices resulting in a poor diet that can contribute to chronic disease risk. The tight link between alveolar bone preservation, tooth retention, better nutritional status, and reduced risk of developing a chronic disease begins with the mitigation of postmenopausal bone loss. The ovariectomized rat, a widely used preclinical model for studying postmenopausal bone loss that mimics deterioration of bone tissue in the hip and spine, can also be used to study mineral and structural changes in alveolar bone to develop drug and/or dietary strategies aimed at tooth retention. This review discusses key findings from studies investigating mandible health and alveolar bone in the ovariectomized rat model. Considerations to maximize the benefits of this model are also included. These include the measurement techniques used, the age at ovariectomy, the duration that a rat is studied after ovariectomy and habitual diet consumed. PMID:26060817

Manganese accumulation in hair and teeth as a biomarker of manganese exposure and neurotoxicity in rats.

PubMed

Liang, Guiqiang; Zhang, Li'e; Ma, Shuyan; Lv, Yingnan; Qin, Huiyan; Huang, Xiaowei; Qing, Li; Li, Qin; Chen, Kangcheng; Xiong, Feng; Ma, Yifei; Nong, Jie; Yang, Xiaobo; Zou, Yunfeng

2016-06-01

Manganese (Mn) is an essential trace element to humans. However, excessive Mn causes cognitive impairment resulting from injury to the central nervous system within the hippocampus. No ideal biomarker is currently available for evaluating Mn exposure and associated neurotoxicity in the body. Hence, this study used Mn levels in the serum (MnS), teeth (MnT), and hair (MnH) as biomarkers for evaluating the association between Mn exposure and cognitive impairment in Mn-treated rats. A total of 32 male Sprague-Dawley rats were randomly divided into four groups, received 0, 5, 10, and 20 mg/(kg day) of MnCl2·4H2O for 5 days a week for 18 weeks, respectively. Lifetime Mn cumulative dose (LMCD) was used to evaluate external Mn exposure. Hippocampus, serum, teeth, and hair specimens were collected from the rats for Mn determination by graphite furnace atomic absorption spectrometry. Learning and memory functions were assessed using the Morris water maze test. Results showed that chronic Mn exposure increased the hippocampus (MnHip), MnS, MnT, and MnH levels, as well as impaired learning and memory function in rats. MnHip, MnT, and MnH levels were positively correlated with LMCD (r = 0.759, r = 0.925, and r = 0.908, respectively; p < 0.05), escape latency (r = 0.862, r = 0.716, and r = 0.814, respectively; p < 0.05), and the number of platform crossings (r = -0.734, r = -0.514, and r = -0.566, respectively; p < 0.05). No association was observed between MnS levels and the number of platform crossings (r = -0.286, p > 0.05). Thus, MnT and MnH detected long-term low-dose Mn exposure. These parameters can be reliable biomarkers for Mn exposure and associated neurotoxicity in Mn-treated rats.

The effect of fluorine and homeopathic medicines in rats fed cariogenic diet.

PubMed

Almeida, N T; Dalmeida, V; Pustiglione, M

2004-07-01

Although some sectors of dentistry have benefited from technological advances, dental caries is still a major problem. Prevention and treatment of dental caries by fluorine is considered a major advance in public health. Nevertheless fluorosis, caused by ingestion of excessive amounts of fluorine during the period of teeth formation, is of great concern. In accordance with the homeopathic doctrine, minimum doses of fluorine and other substances could prevent and/or treat caries. In this experiment, we compared the preventive action of fluorine and evaluated the effect of homeopathic medicines on the teeth of rats fed a cariogenic diet. None of the groups included in this study developed caries. However, microscopy revealed the presence of precipitate and/or deposit in the groups treated with homeopathic medicines. This phenomenon might be due to deposit in the dental surface or precipitation of bacterial plaque or calcium salts. It was not possible to identify the composition of the deposit/precipitate due for technical reasons. In one of the groups treated with homeopathic medicines fur loss was observed in 40% of animals. These reactions might be caused due to the action of the homeopathic medicines.

DELAYED TOOTH REPLANTATION AFTER ROOT SURFACE TREATMENT WITH SODIUM HYPOCHLORITE AND SODIUM FLUORIDE: HISTOMORPHOMETRIC ANALYSIS IN RATS

PubMed Central

Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

2006-01-01

In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin-embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other. PMID:19089038

Delayed tooth replantation after root surface treatment with sodium hypochlorite and sodium fluoride: histomorphometric analysis in rats.

PubMed

Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

2006-04-01

In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin- embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other.

Dental caries area of rat molar expanded by cigarette smoke exposure.

PubMed

Fujinami, Y; Nakano, K; Ueda, O; Ara, T; Hattori, T; Kawakami, T; Wang, P-L

2011-01-01

Passive smoking is the involuntary inhalation of cigarette smoke (CS) and has an adverse impact on oral health. We examined the effect of CS exposure on caries risk and experimental dental caries. Experimental dental caries was induced in rat maxillary molars which were inoculated orally with Streptococcus mutans MT8148 and maintained on a cariogenic diet (diet 2000) and high sucrose water during the experimental period. CS-exposed rats were intermittently housed in an animal chamber with whole-body exposure to CS until killed. Whole saliva was collected before CS exposure (day 0) and for 30 days after the start of CS exposure. Saliva secretion was stimulated by administration of isoproterenol and pilocarpine after anesthesia. Maxillary molars were harvested on day 31. The increase in body weight of the CS-exposed rats was less than that of the control rats. Salivary flow rate, concentration of S. mutans in the stimulated saliva and caries activity score did not significantly differ between 0 and 30 days after the start of CS exposure. Histological examination of the caries-affected area on maxillary molars 30 days after CS exposure showed expansion compared to control rats. In the electron probe microanalysis, no differences were observed between the mineral components of the CS-exposed teeth and the control teeth. These results suggest that CS exposure expands the caries-affected area in the maxillary molars of the rat. Copyright © 2011 S. Karger AG, Basel.

Effects of the bisphosphonate alendronate on molars of young rats after lateral luxation.

PubMed

Rothbarth, Cláudia Pires; Bradaschia-Correa, Vivian; Ferreira, Lorraine Braga; Arana-Chavez, Victor Elias

2014-12-01

The bisphosphonate alendronate (ALN) was employed with the aim of investigating its effects on dental and periodontal tissues after lateral luxation of developing molars. Twenty-one-day-old Wistar rats had their second upper molars laterally luxated. Daily 2.5 mg kg(-1) ALN injections started at the day of the luxation; controls received sterile saline solution. The teeth were analyzed 7, 14, and 21 days after the procedure. On the days cited, the maxillae were fixed, decalcified, and embedded in paraffin or Spurr resin. The paraffin sections were stained with H&E, incubated for TRAP histochemistry or immunolabeled for osteopontin (OPN). Spurr ultrathin sections were examined in a transmission electron microscope. After 21 days, the root apex of luxated molars without ALN was wide open and disorganized and also covered by an irregular layer of cellular cementum, which was not observed in ALN-treated animals. Ankylosis sites were observed in ALN rats in both luxated and non-luxated teeth. The TRAP-positive osteoclasts were more numerous in ALN group, despite their latent ultrastructural appearance without the presence of resorption apparatus compared to controls. OPN immunolabeling revealed a thick immunopositive line in the dentin that must be resultant from the moment of the luxation, while ALN-treated specimens did not present alterations in dentin. The present findings indicate that alendronate inhibits some alterations in dentin and cementum formation induced by dental trauma. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Calreticulin--an endoplasmic reticulum protein with calcium-binding activity is also found in the extracellular matrix.

PubMed

Somogyi, Eszter; Petersson, Ulrika; Hultenby, Kjell; Wendel, Mikael

2003-04-01

Previous studies have reported that calreticulin (CRT), a calcium-binding and chaperoning protein, is expressed only in the endoplasmatic reticulum, nucleus and at the cell surface. In this study we clearly show that odontoblasts and predentin matrix contain CRT. To our knowledge, this is the first time CRT has been described in the extracellular matrix. The expression of CRT was studied by immunohistochemistry, ultrastructural immunocytochemistry and in situ hybridization in developing rat teeth. CRT was detected as a 59-kDa protein in rat pulp cell culture medium and dentin extracellular matrix extract by Western blotting. The presence of the protein was shown in rat odontoblasts and predentin with immunohistochemistry. At the ultrastructural level, the labeling was distributed in the rat odontoblasts, ameloblasts and predentin. Northern blotting showed the presence of CRT mRNA in rat molars, which was confirmed by in situ hybridization in odontoblasts and ameloblasts. We now present the first convincing evidence that CRT is found in extracellular matrix where it may play an important role in mineralization.

Distribution of sup 3 H-proline within transseptal fibers of the rat following release of orthodontic forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Row, K.L.; Johnson, R.B.

1990-10-01

Maxillary right first molar teeth of rats were tipped mesially with an orthodontic appliance for 2 weeks (experimental group), {sup 3}H-proline was injected, and orthodontic forces were removed 6 hr later (time 0). The contralateral molar teeth of treated (internal control group) and age- and weight-matched untreated animals (external control group) were also studied. Diastemata were created between the molar teeth by the orthodontic appliance, and transseptal fibers between first and second (P less than 0.001) and second and third molars (P less than 0.005) were significantly lengthened as compared to external and internal controls at time 0. Diastemata betweenmore » molar teeth were closed 5 days after removal of orthodontic force. Transseptal fibers adjacent to the source of the orthodontic force (mesial region) had the highest mean number of {sup 3}H-proline-labeled proteins at time 0 and at all times following removal of the force (P less than 0.001), and had the highest rate of labeled protein removal (P less than 0.001). Half-lives for removal of 3H-proline-labeled transseptal fiber proteins were significantly greater in mesial and distal regions and significantly less in middle regions of experimentals than in corresponding regions of external controls (P less than 0.001).« less

Effect of Iron Containing Supplements on Rats’ Dental Caries Progression

PubMed Central

Eshghi, AR.; Kowsari-Isfahan, R.; Rezaiefar, M.; Razavi, M.; Zeighami, S.

2012-01-01

Objective: Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children’s diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Materials and Methods: Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. Results: The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Conclusion: Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen. PMID:22924097

Effects of alendronate on restoration of biomechanical properties of periodontium in replanted rat molars.

PubMed

Shibata, T; Komatsu, K; Shimada, A; Shimoda, S; Oida, S; Kawasaki, K; Chiba, M

2004-12-01

We examined the effect of the pretreatment of roots with alendronate on the restoration of the support function of the healing periodontal ligament in replanted rat molars. The left maxillary first molars were extracted, placed in 0.9% NaCl containing 1 mm alendronate (alendronate group) or 0.9% NaCl (control group) for 5 min, and were replanted into their sockets. Groups of animals were killed at 7, 14, and 21 days after replantation. Normal control rats were also killed on the same days. The force required to extract the replanted or normal tooth from its socket was measured, and a load-deformation curve was developed and analyzed. Micro-computed tomography and histologic analyses were also made. The mechanical properties of the healing periodontal ligament in the alendronate group were gradually restored from 7 to 21 days. However, fractures of the roots and bones during mechanical testing occurred in most of the replanted teeth in the control group at 21 days. The rates of restoration of the mechanical strength, extensibility, stiffness, and toughness for the alendronate group at 21 days were 67, 98, 74, and 68% of the normal controls, respectively. Micro-computed tomography and histologic observations revealed that bone-like structures within the pulp and ankylosis between the roots and socket bones occurred commonly in the control group, but were uncommon in the alendronate group. Our findings suggest that the pretreatment with alendronate inhibits the formation of abnormal mineralized tissues and results in better restoration of the support function of the healing periodontal ligament in replanted teeth. (c)Blackwell Munksgaard 2004

[Age-related characteristics of the surface bioelectrical potential of human, canine and rat teeth and features of its distribution over the surface of the crown].

PubMed

Donskiĭ, G I; Pavliuchenko, O N; Palamarchuk, Iu N; Makarova, N Ia

1989-01-01

Using a digital electron voltmeter, bioelectrical potentials (BEPs) of dental crowns have been recorded in 180 patients, 36 dogs, and 93 white non-inbred rats. It has been established that the surface BEP is a marker of dental enamel maturation and does not depend on the species of mammals. On the other hand maturation processes differ in their rate on the cutting edge, equator, and neck: with advancing age algebraic difference between the magnitudes of surface BEPs decreases in humans and increases in dogs and rats.

[Sclerostin expression in periodontal ligaments during movement of orthodontic teeth in rats].

PubMed

Yiwen, Chen; Shang, Gao; Tongtong, Xu; Jiahui, Zhang; Jincheng, Li; Huiyan, Zhang; Jinjin, Lu; Min, Hu; Zhihui, Liu

2016-06-01

This study aims to observe the expression of Sclerostin during movement of orthodontic teeth and determine the effect of this protein on remodeling of periodontal tissues. Twenty-four Wistar rats were chosen. Orthodontic forces were applied between the bilateral incisor and first molar to achieve mesial movement. Rats in each group were executed at different time points (0, 1, 3, 5, 7, 14 d). Morphology of periodontal tissue was observed by hematoxylin-eosin (HE) staining. The number of osteoclasts were observed by tartrate-resistant acid phosphatase (TRAP) staining. Sclerostin expression were observed by immunohistochemical staining. HE staining revealed that the resorption of alveolar bone intensified with prolonged movement. Results of immunohistochemical and TRAP staining revealed that Sclerostin expression and number of osteoclasts were related to duration of movement of orthodontic tooth. After staining for 5 days, the number of osteoclasts and Sclerostin expression reached their peak and then began to decline. The numbers of osteoclasts and the expression level of Sclerostin were higher at the compressive side than those at the tensive side. Sclerostin affected orthodontic tooth movement by inhibiting the Wnt signaling pathway and by indirectly or directly controlling bone morphogenetic protein.

Grading and quantification of dental fluorosis in zebrafish larva.

PubMed

Zhang, Yutao; Zhang, Yanli; Zheng, Xueni; Xu, Rongchen; He, Huiming; Duan, Xiaohong

2016-10-01

The prevalence and severity of dental fluorosis in primary teeth are different from permanent teeth. Previous animal models of dental fluorosis mainly focus on juvenile rats, mice and zebrafish. Our experiment aims to set a dental fluorosis model using zebrafish larva and explore the characteristics of the first generation teeth by fluoride treatment. After the zebrafish eggs were laid, they were exposed to excess fluoride (19ppm, 38ppm and 76ppm) for five days. The morphological characteristics of first generation teeth were examined by H&E staining, whole-mount alizarin red and alcian blue staining, and scanning electron microscope (SEM) technique. With whole-mount alizarin red and alcian blue staining, the tooth cusps presented red in normal control. 19ppm and 38ppmm fluoride resulted in extensive red staining from tooth cusps to the lower 1/3 of teeth. 76ppm fluoride caused malformed teeth with uneven red staining. H&E staining showed that excess fluoride caused cystic-like changes in 38ppm and 76ppm groups. SEM revealed the dose dependent pathological changes in zebrafish enameloid with fluoride treatment. Based on SEM findings, we set 0-4 dental fluorosis index (DFI) score to label the severity of dental fluorosis. Excess fluoride presented a dose dependent fluorosis changes in the teeth of zebrafish larva. The DFI scores in our experiment reflect dose dependent fluorosis changes in a good way and will benefit the future research of dental fluorosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Racemized and Isomerized Proteins in Aging Rat Teeth and Eye Lens

PubMed Central

Warmack, Rebeccah A.; Mansilla, Eduardo; Goya, Rodolfo G.

2016-01-01

Abstract The quantification of aspartic acid racemization in the proteins of nonmetabolically active tissues can be used as a measure of chronological aging in humans and other long-lived organisms. However, very few studies have been conducted in shorter-lived animals such as rodents, which are increasingly used as genetic and metabolic models of aging. An initial study had reported significant changes in the ratio of d- to l-aspartate in rat molars with age. Using a sensitive HPLC method for the determination of d- and l-aspartate from protein hydrolysates, we found no accumulation of d-aspartate in the molars of 17 rats that ranged in age from 2 to 44 months, and the amount of d-aspartate per molar did not correspond with molar eruption date as had been previously reported. However, developing an alternate approach, we found significant accumulation of isomerized aspartyl residues in eye lens proteins that are also formed by spontaneous degradation processes. In this study, we used the human protein l-isoaspartate/d-aspartate O-methyltransferase (PCMT1) as an analytical reagent in a sensitive and convenient procedure that could be used to rapidly examine multiple samples simultaneously. We found levels of isomerized aspartyl residues to be about 35 times higher in the lens extracts of 18-month-old rats versus 2-month-old rats, suggesting that isomerization may be an effective marker for biological aging in this range of ages. Importantly, we found that the accumulation appeared to plateau in rats of 18 months and older, indicating that potentially novel mechanisms for removing altered proteins may develop with age. PMID:26650547

The effect of fluoride on enamel and dentin formation in the uremic rat incisor.

PubMed

Lyaruu, Donacian M; Bronckers, Antonius L J J; Santos, Fernando; Mathias, Robert; DenBesten, Pamela

2008-11-01

Renal impairment in children is associated with tooth defects that include enamel pitting and hypoplasia. However, the specific effects of uremia on tooth formation are not known. In this study, we used rat mandibular incisors, which continuously erupt and contain all stages of tooth formation, to characterize the effects of uremia on tooth formation. We also tested the hypothesis that uremia aggravates the fluoride (F)-induced changes in developing teeth. Rats were subjected to a two-stage 5/6 nephrectomy or sham operation and then exposed to 0 (control) or 50 ppm NaF in drinking water for 14 days. The effects of these treatments on food intake, body growth rate, and biochemical serum parameters for renal function and calcium metabolism were monitored. Nephrectomy reduced food intake and weight gain. Intake of F by nephrectomized rats increased plasma F levels twofold and further decreased food intake and body weight gain. Uremia affected formation of dentin and enamel and was more extensive than the effect of F alone. Uremia also significantly increased predentin width and induced deposition of large amounts of osteodentin-like matrix-containing cells in the pulp chamber. In enamel formation, the cells most sensitive to uremia were the transitional-stage ameloblasts. These data demonstrate that intake of F by rats with reduced renal function impairs F clearance from the plasma and aggravates the already negative effects of uremia on incisor tooth development.

Abnormalities of tooth development in pituitary dwarfism.

PubMed

Kosowicz, J; Rzymski, K

1977-12-01

Roentgenographic studies of the jaws and teeth in a group of forty-eight pituitary dwarfs showed the following abnormalities in the development of the teeth: 1. Delayed shedding of the deciduous teeth. 2. Absence of resorption of the roots of the deciduous teeth at the usual time. 3. Marked delay in eruption of the permanent teeth. 4. Retention of permanent teeth in the maxillary and mandibular shafts. 5. Development of the apical parts of roots of the retained permanent teeth and their growth toward the lower mandibular edge. 6. Displacement of the first molars from the mandibular shaft to rami. 7. Tilting of some of the retained teeth. 8. Small size of the maxilla and mandible with overcrowding of the teeth in these bones. 9. Complete absence of buds of the wisdom teeth, even in patients in the fourth decade of life. 10. Stimulation of development and eruption of the teeth after administration of anabolic drugs. These abnormalities when present in combination depend on growth hormone deficiency since they do not occur in other types of dwarfism.

Morphological study on dental caries induced in WBN/KobSlc rats (Rattus norvegicus) fed a standard laboratory diet.

PubMed

Fukuzato, Yoko; Matsuura, Tetsuro; Ozaki, Kiyokazu; Matsuura, Masahiro; Sano, Tomoya; Nakahara, Yutaka; Kodama, Yasushi; Nakagawa, Akihito; Okamura, Sumie; Suido, Hirohisa; Torii, Kayo; Makino, Taketoshi; Narama, Isao

2009-10-01

In our previous studies, WBN/KobSlc was characterized as a rat strain in which only males began to develop pancreatitis, and then presented with diabetic symptoms. In the course of studying their pancreatic inflammation, we detected molar caries in prediabetic males feeding on a standard diet (CRF-1) widely used for experimental animals. The purpose of this study is to confirm whether the WBN/KobSlc strain is caries-susceptible to the diet reported to be non-cariogenic, and to examine the effect of a prediabetic condition on their dental caries. For a morphological study, 25 male WBN/KobSlc rats aged 3.2-7.8 months and 24 females of the same strain aged 3.3-6.6 months were used, along with 10 males and 10 females of 8.2-month-old F344 rats. Marked dental caries were detected in the mandibular molars of male and female WBN/KobSlc rats regardless of pancreatitis, although no similar changes were observed in any teeth of the F344 strain fed the same diet. Soft X-ray examination revealed that the caries began in the crown and progressed horizontally and vertically, and that a severe radiolucent lesion extensively expanded to the entire crown, corresponding to a macroscopically deleted molar. The caries had gradually developed mainly in the second mandibular molar from more than 3.5 months of age, while none were seen in any rats before that time. The WBN/KobSlc rats were caries-susceptible even to the standard laboratory diet, and pancreatitis was not directly associated with the onset of dental caries in this strain.

A rat model of hypohidrotic ectodermal dysplasia carries a missense mutation in the Edaradd gene

PubMed Central

2011-01-01

Background Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder characterized by sparse hair, oligodontia, and inability to sweat. It is caused by mutations in any of three Eda pathway genes: ectodysplasin (Eda), Eda receptor (Edar), and Edar-associated death domain (Edaradd), which encode ligand, receptor, and intracellular adaptor molecule, respectively. The Eda signaling pathway activates NF-κB, which is central to ectodermal differentiation. Although the causative genes and the molecular pathway affecting HED have been identified, no curative treatment for HED has been established. Previously, we found a rat spontaneous mutation that caused defects in hair follicles and named it sparse-and-wavy (swh). Here, we have established the swh rat as the first rat model of HED and successfully identified the swh mutation. Results The swh/swh rat showed sparse hair, abnormal morphology of teeth, and absence of sweat glands. The ectoderm-derived glands, meibomian, preputial, and tongue glands, were absent. We mapped the swh mutation to the most telomeric part of rat Chr 7 and found a Pro153Ser missense mutation in the Edaradd gene. This mutation was located in the death domain of EDARADD, which is crucial for signal transduction and resulted in failure to activate NF-κB. Conclusions These findings suggest that swh is a loss-of-function mutation in the rat Edaradd and indicate that the swh/swh rat would be an excellent animal model of HED that could be used to investigate the pathological basis of the disease and the development of new therapies. PMID:22013926

Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

PubMed Central

Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

2012-01-01

This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. PMID:22780101

Pregabalin role in inhibition of morphine analgesic tolerance and physical dependency in rats.

PubMed

Hasanein, Parisa; Shakeri, Saeed

2014-11-05

Pregabalin is recently proposed as analgesic or adjuvant in pain management. While previous preclinical investigations have evaluated pregabalin-opioid interactions, the effect of pregabalin on opioid tolerance and dependency has not yet been studied. Here we evaluated the effects of different doses of pregabalin (50, 100 and 200mg/kg, s.c.) on morphine-induced tolerance and dependency in rats. Adult male Wistar rats were rendered tolerant to analgesic effect of morphine by injection of morphine (10mg/kg, s.c.) twice daily for 7 days. To develop morphine dependence, rats were given escalating doses of morphine. To determine the effect of pregabalin on the development of morphine tolerance and dependence, different doses of pregabalin were administrated before morphine. The tail-flick and naloxone precipitation withdrawal tests were used to evaluate the degree of tolerance and dependence, respectively. Chronic morphine-injected rats showed significant decrements in the percentage maximum possible effect (%MPE) of morphine on the days 5 and 7 (32.5%±3.5, 21.5%±4, respectively) compared to the first day (100%) which showed morphine tolerance. Pregabalin 200mg/kg completely prevented the development of morphine tolerance. In addition, concomitant treatment of morphine with pregabalin attenuated almost all of the naloxone-induced withdrawal signs which include weight loss, jumping, penis licking, teeth chattering, wet dog shakes, rearing, standing, sniffing, face grooming and paw tremor. These data show that pregabaline has a potential anti-tolerant/anti-dependence property against chronic usage of morphine. Therefore, pregabalin appears to be a promising candidate for the treatment of opioid addiction after confirming by future clinical studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Musserakis sulawesiensis gen. et sp. n. (Nematoda: Heterakidae) collected from Echiothrix centrosa (Rodentia: Muridae), an old endemic rat of Sulawesi, Indonesia.

PubMed

Hasegawa, Hideo; Dewi, Kartika; Asakawa, Mitsuhiko

2014-11-04

Musserakis sulawesiensis gen. et sp. n. (Nematoda: Heterakidae) is described from the large-bodied shrew rat, Echiothrix centrosa, one of the old endemic rats of Sulawesi, Indonesia. Musserakis is readily distinguished from other heterakid genera by having non-recurrent and non-anastomosing cephalic cordons, by lacking papillae between papillae groups around precloacal sucker and cloacal aperture and by lacking teeth in the pharyngeal portion. The spicules are equal but with marked dimorphism among individuals. Heterakids collected from other old endemic murids examined, i.e., Crunomys celebensis, Tateomys macrocercus and Tateomys rhinogradoides, and the new endemic rats of Sulawesi, were Heterakis spumosa Schneider, 1866, a cosmopolitan nematode of various murids. It is suggested that M. sulawesiensis is specific to Echiothrix.

[Isolation of cariogenic Streptococcus mutans and the inhibitory effect of egg yolk antibody on caries].

PubMed

Li, X L; Zhang, Z; Li, Z X; Deng, N J; Zeng, B; Chen, Y M

2017-04-09

Objective: To isolate the cariogenic Streptococcus mutans (Sm) strains and study the therapeutical effect of egg yolk antibody (IgY) of the Sm on dental caries development. Methods: Sm strains were isolated from the children's dental plaque samples. Morphological, biochemical and molecular biological methods were applied to identify the serotype, acid producing and adhesion abilities of isolated Sm strains. After inactivation one of the Sm strains was used as antigen to immune laying hens to collect and extract the specific anti-Sm IgY. The rats were infected with Sm (serotype e). After 16 weeks of infection, all the rats were found developing dental caries. The rats were then randomly divided into two groups. The rats in experimental group were supplied with diet containing anti-Sm IgY while the rats in control group with normal IgY. All rats were sacrificed after another 8 weeks' observation. The degree of caries for each rat was assessed using Keyes' method. Results: We isolated 7 Sm strains from the children's dental plaque samples in the present study. The numbers of serotype c, e, f, k were 3, 2, 0 and 2, respectively. All strains showed similar morphological and biochemical characters as standard UA159 Sm strain, and possessed strong capabilities of acid production and adherence. Interestingly, even the same serotypec strains, such as No.3 and No.7 strains, demonstrated significant difference on acid producing and adherence capabilities. After 16 weeks infection with serotype e strain, the rats' mandibular teeth were apparently decayed, and treatment with specific anti-Sm IgY obviously attenuated the development of caries in the experiment group rats (16.4±2.0) compared with that in the control group rats (30.2±9.3) ( P< 0.05) determined by Keyes' method. Conclusions: Seven cariogenic Sm strains of different serotypes were isolated, which possesses similar morphology and biochemical characters. Although belonging to the same serotype strains they always show significant difference in acid-producing and adherencec apabilities. Further experiment provides evidences that the serotype e strain could obviously induce caries independently, and employment of specific anti-Sm IgY as passive immunotherapy additive might effectively inhibit the further development of dental caries.

A simple and efficient method for generating Nurr1-positive neuronal stem cells from human wisdom teeth (tNSC) and the potential of tNSC for stroke therapy.

PubMed

Yang, Kuo-Liang; Chen, Mei-Fang; Liao, Chia-Hsin; Pang, Cheng-Yoong; Lin, Py-Yu

2009-01-01

We have isolated human neuronal stem cells from exfoliated third molars (wisdom teeth) using a simple and efficient method. The cultured neuronal stem cells (designated tNSC) expressed embryonic and adult stem cell markers, markers for chemotatic factor and its corresponding ligand, as well as neuron proteins. The tNSC expressed genes of Nurr1, NF-M and nestin. They were used to treat middle cerebral artery occlusion (MCAO) surgery-inflicted Sprague-Dawley (SD) rats to assess their therapeutic potential for stroke therapy. For each tNSC cell line, a normal human impacted wisdom tooth was collected from a donor with consent. The tooth was cleaned thoroughly with normal saline. The molar was vigorously shaken or vortexed for 30 min in a 50-mL conical tube with 15-20mL normal saline. The mixture of dental pulp was collected by centrifugation and cultured in a 25-cm(2) tissue culture flask with 4-5mL Medium 199 supplemented with 5-10% fetal calf serum. The tNSC harvested from tissue culture, at a concentration of 1-2x10(5), were suspended in 3 microL saline solution and injected into the right dorsolateral striatum of experimental animals inflicted with MCAO. Behavioral measurements of the tNSC-treated SD rats showed a significant recovery from neurologic dysfunction after MCAO treatment. In contrast, a sham group of SD rats failed to recover from the surgery. Immunohistochemistry analysis of brain sections of the tNSC-treated SD rats showed survival of the transplanted cells. These results suggest that adult neuronal stem cells may be procured from third molars, and tNSC thus cultivated have potential for treatment of stroke-inflicted rats.

A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth.

PubMed

Yu, Fang; Cai, Wenping; Jiang, Beizhan; Xu, Laijun; Liu, Shangfeng; Zhao, Shouliang

2018-01-01

Supernumerary teeth are teeth that are present in addition to normal teeth. Although several hypotheses and some molecular signalling pathways explain the formation of supernumerary teeth, but their exact disease pathogenesis is unknown. To study the molecular mechanisms of supernumerary tooth-related syndrome (Gardner syndrome), a deeper understanding of the aetiology of supernumerary teeth and the associated syndrome is needed, with the goal of inhibiting disease inheritance via prenatal diagnosis. We recruited a Chinese family with Gardner syndrome. Haematoxylin and eosin staining of supernumerary teeth and colonic polyp lesion biopsies revealed that these patients exhibited significant pathological characteristics. APC gene mutations were detected by PCR and direct sequencing. We revealed the pathological pathway involved in human supernumerary tooth development and the mouse tooth germ development expression profile by RNA sequencing (RNA-seq). Sequencing analysis revealed that an APC gene mutation in exon 15, namely 4292-4293-Del GA, caused Gardner syndrome in this family. This mutation not only initiated the various manifestations typical of Gardner syndrome but also resulted in odontoma and supernumerary teeth in this case. Furthermore, RNA-seq analysis of human supernumerary teeth suggests that the APC gene is the key gene involved in the development of supernumerary teeth in humans. The mouse tooth germ development expression profile shows that the APC gene plays an important role in tooth germ development. We identified a new mutation in the APC gene that results in supernumerary teeth in association with Gardner syndrome. This information may shed light on the molecular pathogenesis of supernumerary teeth. Gene-based diagnosis and gene therapy for supernumerary teeth may become available in the future, and our study provides a high-resolution reference for treating other syndromes associated with supernumerary teeth. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Biological tooth replacement

PubMed Central

Sartaj, Rachel; Sharpe, Paul

2006-01-01

Teeth develop from a series of reciprocal interactions that take place between epithelium and mesenchyme during development of the mouth that begin early in mammalian embryogenesis. The molecular control of key processes in tooth development such as initiation, morphogenesis and cytodifferentiation are being increasingly better understood, to the point where this information can be used as the basis for approaches to produce biological replacement teeth (BioTeeth). This review outlines the current approaches, ideas and progress towards the production of BioTeeth that could form an alternative method for replacing lost or damaged teeth. PMID:17005022

90Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi Nuclear Power Plant accident

NASA Astrophysics Data System (ADS)

Koarai, Kazuma; Kino, Yasushi; Takahashi, Atsushi; Suzuki, Toshihiko; Shimizu, Yoshinaka; Chiba, Mirei; Osaka, Ken; Sasaki, Keiichi; Fukuda, Tomokazu; Isogai, Emiko; Yamashiro, Hideaki; Oka, Toshitaka; Sekine, Tsutomu; Fukumoto, Manabu; Shinoda, Hisashi

2016-04-01

Here we determined the 90Sr concentrations in the teeth of cattle abandoned in the evacuation area of the Fukushima-Daiichi Nuclear Power Plant (FNPP) accident. 90Sr activity concentrations in the teeth varied from 6-831 mBq (g Ca)-1 and exhibited a positive relationship with the degree of radioactive contamination that the cattle experienced. Even within an individual animal, the specific activity of 90Sr (Bq (g Sr)-1) varied depending on the development stage of the teeth during the FNPP accident: teeth that were early in development exhibited high 90Sr specific activities, while teeth that were late in development exhibited low specific activities. These findings demonstrate that 90Sr is incorporated into the teeth during tooth development; thus, tooth 90Sr activity concentrations reflect environmental 90Sr levels during tooth formation. Assessment of 90Sr in teeth could provide useful information about internal exposure to 90Sr radiation and allow for the measurement of time-course changes in the degree of environmental 90Sr pollution.

(90)Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi Nuclear Power Plant accident.

PubMed

Koarai, Kazuma; Kino, Yasushi; Takahashi, Atsushi; Suzuki, Toshihiko; Shimizu, Yoshinaka; Chiba, Mirei; Osaka, Ken; Sasaki, Keiichi; Fukuda, Tomokazu; Isogai, Emiko; Yamashiro, Hideaki; Oka, Toshitaka; Sekine, Tsutomu; Fukumoto, Manabu; Shinoda, Hisashi

2016-04-05

Here we determined the (90)Sr concentrations in the teeth of cattle abandoned in the evacuation area of the Fukushima-Daiichi Nuclear Power Plant (FNPP) accident. (90)Sr activity concentrations in the teeth varied from 6-831 mBq (g Ca)(-1) and exhibited a positive relationship with the degree of radioactive contamination that the cattle experienced. Even within an individual animal, the specific activity of (90)Sr (Bq (g Sr)(-1)) varied depending on the development stage of the teeth during the FNPP accident: teeth that were early in development exhibited high (90)Sr specific activities, while teeth that were late in development exhibited low specific activities. These findings demonstrate that (90)Sr is incorporated into the teeth during tooth development; thus, tooth (90)Sr activity concentrations reflect environmental (90)Sr levels during tooth formation. Assessment of (90)Sr in teeth could provide useful information about internal exposure to (90)Sr radiation and allow for the measurement of time-course changes in the degree of environmental (90)Sr pollution.

90Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi Nuclear Power Plant accident

PubMed Central

Koarai, Kazuma; Kino, Yasushi; Takahashi, Atsushi; Suzuki, Toshihiko; Shimizu, Yoshinaka; Chiba, Mirei; Osaka, Ken; Sasaki, Keiichi; Fukuda, Tomokazu; Isogai, Emiko; Yamashiro, Hideaki; Oka, Toshitaka; Sekine, Tsutomu; Fukumoto, Manabu; Shinoda, Hisashi

2016-01-01

Here we determined the 90Sr concentrations in the teeth of cattle abandoned in the evacuation area of the Fukushima-Daiichi Nuclear Power Plant (FNPP) accident. 90Sr activity concentrations in the teeth varied from 6–831 mBq (g Ca)−1 and exhibited a positive relationship with the degree of radioactive contamination that the cattle experienced. Even within an individual animal, the specific activity of 90Sr (Bq (g Sr)−1) varied depending on the development stage of the teeth during the FNPP accident: teeth that were early in development exhibited high 90Sr specific activities, while teeth that were late in development exhibited low specific activities. These findings demonstrate that 90Sr is incorporated into the teeth during tooth development; thus, tooth 90Sr activity concentrations reflect environmental 90Sr levels during tooth formation. Assessment of 90Sr in teeth could provide useful information about internal exposure to 90Sr radiation and allow for the measurement of time-course changes in the degree of environmental 90Sr pollution. PMID:27045764

The effects of topical application of bisphosphonates on replanted rat molars.

PubMed

Choi, Sung Chul; Kwon, Yong-Dae; Kim, Kwang Chul; Kim, Gue-Tae

2010-12-01

The purpose of this study was to evaluate the potential usefulness of two bisphosphonates (BPs) (etidronate and zoledronate), compared with that of alendronate, which is a well-known drug for delayed replantation, in decreasing or preventing inflammatory root resorption and replacement root resorption in replanted teeth. Eighty-four Sprague Dawley rat maxillary first molars were extracted, dried for 60 min and then replanted after root treatment. The rats were divided into four groups (control, alendronate, etidronate, zoledronate) as following treatments of avulsed root before replantation. At 7, 14, and 28 days postreplantation, the animals were sacrificed and the samples obtained and process for microscopic analysis. The data were statistically analyzed with the SPSS procedure, anova test and each test was complemented by the Tukey's post hoc test. The result indicated that topical application of alendronate and zoledronate, both nitrogen containing BPs, prevented inflammatory root resorption and inflammatory cell response in the delayed replantation model. Both drugs were demonstrated similar effects in the delayed tooth replantation model (P = 0.9). Etidronate did not prevent inflammatory root resorption and inflammation in the delayed replantation (P < 0.05). No significant differences in replacement root resorption were observed among all drugs. These results suggest that when teeth are dried and not replanted immediately, zoledronate, like alendronate, may prevent root resorption and facilitates the regeneration of periodontal tissues after replantation. © 2010 John Wiley & Sons A/S.

90Sr specific activity of teeth of abandoned cattle after the Fukushima accident - teeth as an indicator of environmental pollution.

PubMed

Koarai, Kazuma; Kino, Yasushi; Takahashi, Atsushi; Suzuki, Toshihiko; Shimizu, Yoshinaka; Chiba, Mirei; Osaka, Ken; Sasaki, Keiichi; Urushihara, Yusuke; Fukuda, Tomokazu; Isogai, Emiko; Yamashiro, Hideaki; Oka, Toshitaka; Sekine, Tsutomu; Fukumoto, Manabu; Shinoda, Hisashi

2018-03-01

90 Sr specific activity in the teeth of young cattle that were abandoned in Kawauchi village and Okuma town located in the former evacuation areas of the Fukushima-Daiichi Nuclear Power Plant (FNPP) accident were measured. Additionally, specific activity in contaminated surface soils sampled from the same area was measured. (1) All cattle teeth examined were contaminated with 90 Sr. The specific activity, however, varied depending on the developmental stage of the teeth during the FNPP accident; teeth that had started development before the accident exhibited comparatively lower values, while teeth developed mainly after the accident showed higher values. (2) Values of 90 Sr-specific activity in teeth formed after the FNPP accident were higher than those of the bulk soil but similar to those in the exchangeable fraction (water and CH 3 COONH 4 soluble fractions) of the soil. The findings suggest that 90 Sr was incorporated into the teeth during the process of development, and that 90 Sr in the soluble and/or leachable fractions of the soil might migrate into teeth and contribute to the amount of 90 Sr in the teeth. Thus, the concentration of 90 Sr in teeth formed after the FNPP accident might reflect the extent of 90 Sr pollution in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wisdom Teeth Management

MedlinePlus

Wisdom Teeth Management Wisdom teeth, or third molars, are the last teeth to develop and appear in your mouth. They come ... of third molars, disease status, and to suggest management options ranging from removal to a monitored retention ...

Revitalization of open apex teeth with apical periodontitis using a collagen-hydroxyapatite scaffold.

PubMed

Nevins, Alan J; Cymerman, Jerome J

2015-06-01

An enhanced revision of the revitalization endodontic technique for immature teeth with apical periodontitis has been described. It includes the addition of collagen-hydroxyapatite scaffold to the currently practiced revascularization technique. Four cases treated in series are presented in this report, 1 case involving 2 teeth. Periapical diagnoses of immature teeth included "asymptomatic apical periodontitis," "symptomatic apical periodontitis," and "acute apical abscess." Additionally, 1 fully developed tooth that had undergone root canal treatment that failed had a periapical diagnosis of acute apical abscess. An established revascularization protocol was used for all teeth. In addition to stimulating blood clots, all teeth were filled with collagen-hydroxyapatite scaffolds. Periapical radiolucencies healed in all teeth, and diffuse radiopacity developed within the coronal portions of canal spaces. Root development with root lengthening occurred in the immature nonvital maxillary premolar that had not undergone prior treatment. The technique of adding a collagen-hydroxyapatite scaffold to the existing revitalization protocol has been described in which substantial hard tissue repair has occurred. This may leave teeth more fully developed and less likely to fracture. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Biocompatibility evaluation of alendronate paste in rat's subcutaneous tissue.

PubMed

Mori, Graziela Garrido; de Moraes, Ivaldo Gomes; Nunes, Daniele Clapes; Castilho, Lithiene Ribeiro; Poi, Wilson Roberto; Capaldi, Maria Luciana P Manzoli

2009-04-01

Alendronate is a known inhibitor of root resorption and the development of alendronate paste would enhance its utilization as intracanal medication. Therefore, this study aimed to investigate the biocompatibility of experimental alendronate paste in subcutaneous tissue of rats, for utilization in teeth susceptible to root resorption. The study was conducted on 15 male rats, weighing approximately 180-200 grams. The rats' dorsal regions were submitted to one incision on the median region and, laterally to the incision, the subcutaneous tissue was raised and gently dissected for introduction of two tubes, in each rat. The tubes were sealed at one end with gutta-percha and taken as control. The tubes were filled with experimental alendronate paste. The animals were killed at 7, 15 and 45 days after surgery and the specimens were processed in laboratory. The histological sections were stained with hematoxylin-eosin and analyzed by light microscopy. Scores were assigned to the inflammatory process and statistically compared by the Tukey test (P < 0.05). Alendronate paste promoted severe inflammation process at 7 days, with statistically significant difference compared to the control (P < 0.05%). However, at 15 days, there was a regression of inflammation and the presence of connective tissue with collagen fibers, fibroblasts and blood vessels was observed. After 45 days, it was observed the presence of well-organized connective tissue, with collagen fibers and fibroblasts, and few inflammatory cells. No statistical difference was observed between the control and experimental paste at 15 and 45 days. The experimental alendronate paste was considered biocompatible with subcutaneous tissue of rat.

The Effects of Inflammatory Tooth Pain on Anxiety in Adult Male Rats

PubMed Central

Raoof, Maryam; Ebrahimnejad, Hamed; Abbasnejad, Mehdi; Amirkhosravi, Ladan; Raoof, Ramin; Esmaeili Mahani, Saeed; Ramazani, Mohsen; Shokouhinejad, Noushin; Khoshkhounejad, Mehrfam

2016-01-01

Introduction: This study aimed to examine the effects of induced inflammatory tooth pain on anxiety level in adult male rats. Methods: The mandibular incisors of 56 adult male rats were cut off and prefabricated crowns were fixed on the teeth. Formalin and capsaicin were injected intradentally to induce inflammatory tooth pain. Diazepam treated group received diazepam 30 minutes before intradental injection. The anxiety-related behavior was evaluated with elevated plus maze test. Results: Intradental application of chemical noxious stimuli, capsaicin and formalin, significantly affected nociceptive behaviors (P<0.001). Capsaicin (P<0.001) and formalin (P<0.01) significantly increased the anxiety levels in rats by decrease in the duration of time spent in open arm and increase in the duration of time spent in closed arm. Rats that received capsaicin made fewer open arm entries compared to the control animals (P<0.05). Capsaicin (P<0.001) and formalin (P<0.01) treated rats showed more stretch attend postures compared to the control and sham operated animals. In diazepampretreated rats, capsaicin induced algesic effect was prevented (P<0.001). Conclusion: Inflammatory pulpal pain has anxiogenic effect on rats, whereas diazepam premedication showed both anxiolytic and pain reducing effects. PMID:27563419

Industrial Noise and Tooth Wear - Experimental Study

PubMed Central

Cavacas, Maria Alzira; Tavares, Vitor; Borrecho, Gonçalo; Oliveira, Maria João; Oliveira, Pedro; Brito, José; Águas, Artur; dos Santos, José Martins

2015-01-01

Tooth wear is a complex multifactorial process that involves the loss of hard dental tissue. Parafunctional habits have been mentioned as a self-destructive process caused by stress, which results in hyperactivity of masticatory muscles. Stress manifests itself through teeth grinding, leading to progressive teeth wear. The effects of continuous exposure to industrial noise, a “stressor” agent, cannot be ignored and its effects on the teeth must be evaluated. Aims: The aim of this study was to ascertain the effects of industrial noise on dental wear over time, by identifying and quantifying crown area loss. Material and Methods: 39 Wistar rats were used. Thirty rats were divided in 3 experimental groups of 10 animals each. Animals were exposed to industrial noise, rich in LFN components, for 1, 4 and 7 months, with an average weekly exposure of 40 hours (8h/day, 5 days/week with the weekends in silence). The remaining 9 animals were kept in silence. The areas of the three main cusps of the molars were measured under light microscopy. Statistical analysis used: A two-way ANOVA model was applied at significance level of 5%. Results: The average area of the molar cusps was significantly different between exposed and non-exposed animals. The most remarkable differences occurred between month 1 and 4. The total crown loss from month 1 to month 7 was 17.3% in the control group, and 46.5% in the exposed group, and the differences between these variations were significant (p<0.001). Conclusions: Our data suggest that industrial noise is an important factor in the pathogenesis of tooth wear. PMID:25798052

Evaluation of the topical effect of alendronate on the root surface of extracted and replanted teeth. Microscopic analysis on rats' teeth.

PubMed

Lustosa-Pereira, Adriana; Garcia, Roberto Brandão; de Moraes, Ivaldo Gomes; Bernardineli, Norberti; Bramante, Clovis Monteiro; Bortoluzzi, Eduardo Antunes

2006-02-01

The treatment of choice for tooth avulsion is replantation. The ideal replantation should be realized as quickly as possible, or at least, the avulsed tooth should be kept in an adequate solution to preserve the periodontal ligament attached to the root. If that is not possible, treatment of the radicular surface should be done in order to prevent radicular resorption. The purpose of this study was to test sodium alendronate as a substance for topical treatment of the radicular surface of avulsed teeth in an attempt to prevent the occurrence of dental resorptions. Fifty-four rat maxillary right central incisors were extracted and replanted. Group I--extra-alveolar dry period of 15 min, intracanal dressing with calcium hydroxide (CALEN, S.S. White, Artigos Dentários LTDA, Rio de Janeiro, Brazil) and replantation; Groups II and III - extra-alveolar dry periods of 30 and 60 min, respectively, immersion in 1% sodium hypochlorite for 30 min for removal of the periodontal ligament, washing in saline solution for 5 min, and treatment of the radicular surface with 3.2 mg/l sodium alendronate solution for 10 min. Intracanal dressing with calcium hydroxide and replantation followed. At 15, 60, and 90 days post-reimplantation, the animals were killed and the samples obtained and processed for microscopic analysis. The results indicated that sodium alendronate was able to reduce the incidence of radicular resorption, but not of dental ankylosis. No significant differences were observed regarding variations in the extra-alveolar periods among the groups.

Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

PubMed

Moyer, Joshua K; Riccio, Mark L; Bemis, William E

2015-07-01

Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias. © 2015 Wiley Periodicals, Inc.

CMT for materials science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinney, J.

This session is comprised of two articles by John Kinney describing biomedical and other uses for computerized tomography. In the first article, Kinney describes the use of a three-dimensional x-ray tomographic microscope to image the trabecular bone architecture of the proximal tibias of rats in vivo. Research in this field may help to detect the earliest stages of hypoestrogenemic bone loss and may help to more rapidly test the effectiveness of new clinical treatments for this major public health problem. The second article describes recent advances in X-ray tomography using synchrotron radiation to evaluate microstructures in ceramic matrix composites, bonemore » loss in osteoporosis, and the development of carries lesions in teeth.« less

Application of a nuclear microprobe to the study of calcified tissues

NASA Astrophysics Data System (ADS)

Coote, Graeme E.; Vickridge, Ian C.

1988-03-01

The mineral fraction of calcified tissue is largely calcium hydroxyapatite (bones and teeth) or calcium carbonate (shells and fish otoliths). Apatite has such a strong affinity for fluoride ions that the F/Ca ratio can vary markedly with position in a bone or tooth, depending on the amount of fluoride present at the time of calcification or partial recrystallization. New biological information can be obtained by introducing extra fluoride into the diet of an animal and using a microprobe later to scan sections of bones or teeth. In suitable burial sites extra fluoride is introduced after death, and the new distribution may have applications in forensic science and archaeology. Fish otoliths are also of interest since a new carbonate layer is formed each day and the distribution of trace elements may record some aspects of the fish's life history. Results from the following studies are presented: fluorine distributions in the teeth of sheep which ingested extra fluoride for known periods; distributions of calcium and fluorine in femurs of rats which drank water high in fluoride for periods from 2 to 15 weeks; calcium and fluorine distributions in artificially-prepared lesions in tooth enamel; diffusion profiles in archaeological human teeth and animal bones; patterns in the strontium/calcium ratio in sectioned otoliths of several species of fish.

Adult Human Gingival Epithelial Cells as a Source for Whole-tooth Bioengineering

PubMed Central

Angelova Volponi, A.; Kawasaki, M.; Sharpe, P.T.

2013-01-01

Teeth develop from interactions between embryonic oral epithelium and neural-crest-derived mesenchyme. These cells can be separated into single-cell populations and recombined to form normal teeth, providing a basis for bioengineering new teeth if suitable, non-embryonic cell sources can be identified. We show here that cells can be isolated from adult human gingival tissue that can be expanded in vitro and, when combined with mouse embryonic tooth mesenchyme cells, form teeth. Teeth with developing roots can be produced from this cell combination following transplantation into renal capsules. These bioengineered teeth contain dentin and enamel with ameloblast-like cells and rests of Malassez of human origin. PMID:23458883

Initiation of teeth from the dental lamina in the ferret.

PubMed

Jussila, Maria; Crespo Yanez, Xenia; Thesleff, Irma

2014-01-01

Mammalian tooth development is characterized by formation of primary teeth that belong to different tooth classes and are later replaced by a single set of permanent teeth. The first primary teeth are initiated from the primary dental lamina, and the replacement teeth from the successional dental lamina at the lingual side of the primary teeth. An interdental lamina connects the primary tooth germs together. Most mammalian tooth development research is done on mouse, which does not have teeth in all tooth classes, does not replace its teeth, and does not develop an interdental lamina. We have used the ferret (Mustela putorius furo) as a model animal to elucidate the morphological changes and gene expression during the development of the interdental lamina and the initiation of primary teeth. In addition we have analyzed cell-cell signaling taking place in the interdental lamina as well as in the successional lamina during tooth replacement. By 3D reconstructions of serial histological sections we observed that the morphogenesis of the interdental lamina and the primary teeth are intimately linked. Expression of Pitx2 and Foxi3 in the interdental lamina indicates that it has odontogenic identity, and there is active signaling taking place in the interdental lamina. Bmp4 is coexpressed with the stem cell factor Sox2 at its lingual aspect suggesting that the interdental lamina may retain competence for tooth initiation. We show that when tooth replacement is initiated there is Wnt pathway activity in the budding successional lamina and adjacent mesenchyme but no active Fgf or Eda signaling. Genes associated with human tooth replacement phenotypes, including Runx2 and Il11rα, are mostly expressed in the mesenchyme around the successional lamina in the ferret. Our results highlight the importance of the dental lamina in the mammalian tooth development during the initiation of both primary and replacement teeth. Copyright © 2013 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Dental peculiarities in the silvery mole-rat: an original model for studying the evolutionary and biological origins of continuous dental generation in mammals

PubMed Central

Šumbera, Radim

2015-01-01

Unravelling the evolutionary and developmental mechanisms that have impacted the mammalian dentition, since more than 200 Ma, is an intricate issue. Interestingly, a few mammal species, including the silvery mole-rat Heliophobius argenteocinereus, are able to replace their dentition by the addition of supernumerary molars at the back of jaw migrating then toward the front. The aim here was to demonstrate the potential interest of further studying this rodent in order to better understand the origins of continuous dental replacement in mammals, which could also provide interesting data concerning the evolution of limited dental generation occurring in first mammals. In the present study, we described the main stages of the dental eruptive sequence in the silvery mole-rat and the associated characteristics of horizontal replacement using X-ray microtomography. This was coupled to the investigation of other African mole-rats which have no dental replacement. This method permitted to establish evidence that the initial development of the dentition in Heliophobius is comparable to what it is observed in most of African mole-rats. This rodent first has premolars, but then identical additional molars, a mechanism convergent to manatees and the pygmy rock-wallaby. Evidence of continuous replacement and strong dental dynamics were also illustrated in Heliophobius, and stressed the need to deeply investigate these aspects for evolutionary, functional and developmental purposes. We also noticed that two groups of extinct non-mammalian synapsids convergently acquired this dental mechanism, but in a way differing from extant mammals. The discussion on the diverse evolutionary origins of horizontal dental replacement put emphasis on the necessity of focusing on biological parameters potentially involved in both continuous and limited developments of teeth in mammals. In that context, the silvery mole-rat could appear as the most appropriate candidate to do so. PMID:26401449

X-linked hypophosphatemia: the mutant gene is expressed in teeth as well as in kidney.

PubMed Central

Shields, E D; Scriver, C R; Reade, T; Fujiwara, T M; Morgan, K; Ciampi, A; Schwartz, S

1990-01-01

Mutation at a locus (HPDR) on the X chromosome (McKusick 30780 [HPDR1]; 30781 [HPDR2]) causes impaired renal phosphate transport, hypophosphatemia, and an associated impairment in the process of mineralization in bone and teeth (X-linked hypophosphatemia [XLH]). We measured the dental pulp profile area (PRATIO [= pulp area/tooth area]) and serum phosphorus (Pi) values in uniformly treated XLH patients (six males, 81 teeth, 1,457 Pi values; 11 females, 129 teeth, 1,439 Pi values). Serum Pi values, reflecting the metabolic environment of tooth development, were obtained by repeated measurement between 1 mo and 26 years of age during treatment. PRATIO values calculated from standardized Rinn radiographs were used as outcome measurements of tooth development in XLH patients and in age-matched controls (12 males, 100 teeth; 27 females, 275 teeth). Age-dependent serum Pi values were not different in the treated XLH males and females. In teeth forming primary dentin there was no gene dosage effect on PRATIO values apparent in subjects below 15 years of age. However, in teeth forming secondary dentin a gene dosage was found in the subjects aged 15 to 25 years: XLH male teeth (n = 65) mean +/- SD = 0.163 +/- 0.046; XLH female teeth (n = 75) mean +/- SD = 0.137 +/- 0.039; control teeth (n = 209) mean +/- SD = 0.116 +/- 0.023; (higher PRATIO values mean less development or mineralization of secondary dentin); differences in these PRATIO values (males vs. female and XLH vs. control) were significant by mixed-model analysis of variance.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2155529

Early development of rostrum saw-teeth in a fossil ray tests classical theories of the evolution of vertebrate dentitions.

PubMed

Smith, Moya Meredith; Riley, Alex; Fraser, Gareth J; Underwood, Charlie; Welten, Monique; Kriwet, Jürgen; Pfaff, Cathrin; Johanson, Zerina

2015-10-07

In classical theory, teeth of vertebrate dentitions evolved from co-option of external skin denticles into the oral cavity. This hypothesis predicts that ordered tooth arrangement and regulated replacement in the oral dentition were also derived from skin denticles. The fossil batoid ray Schizorhiza stromeri (Chondrichthyes; Cretaceous) provides a test of this theory. Schizorhiza preserves an extended cartilaginous rostrum with closely spaced, alternating saw-teeth, different from sawfish and sawsharks today. Multiple replacement teeth reveal unique new data from micro-CT scanning, showing how the 'cone-in-cone' series of ordered saw-teeth sets arrange themselves developmentally, to become enclosed by the roots of pre-existing saw-teeth. At the rostrum tip, newly developing saw-teeth are present, as mineralized crown tips within a vascular, cartilaginous furrow; these reorient via two 90° rotations then relocate laterally between previously formed roots. Saw-tooth replacement slows mid-rostrum where fewer saw-teeth are regenerated. These exceptional developmental data reveal regulated order for serial self-renewal, maintaining the saw edge with ever-increasing saw-tooth size. This mimics tooth replacement in chondrichthyans, but differs in the crown reorientation and their enclosure directly between roots of predecessor saw-teeth. Schizorhiza saw-tooth development is decoupled from the jaw teeth and their replacement, dependent on a dental lamina. This highly specialized rostral saw, derived from diversification of skin denticles, is distinct from the dentition and demonstrates the potential developmental plasticity of skin denticles. © 2015 The Authors.

A novel whole tooth-in-jaw-bone culture of rat molars: morphological, immunohistochemical, and laser capture microdissection analysis.

PubMed

Chokechanachaisakul, Uraiwan; Kaneko, Tomoatsu; Yamanaka, Yusuke; Okiji, Takashi; Suda, Hideaki

2012-10-01

In conventional whole-tooth culture systems, limitation exists regarding maintenance of the vitality of the dental pulp, because this tissue is encased in rigid dentin walls that hinder nutrition supply. We here report a whole tooth-in-jaw-bone culture system of rat mandibular first molars, where transcardiac perfusion with culture medium was carried out before placement of the jaw bone into culture medium, aiming to facilitate longer time preservation of the dental pulp tissue. Following 7 days of culture, the pulp tissues were analyzed by histology and immunohistochemistry to ED2 (antiresident macrophage). ED2-positive macrophages were also analyzed for their Class II MHC, interleukin-6 (IL-6), and p53 mRNA expression levels by means of immune-laser capture microdissection (immune-LCM). Dentin sialophosphoprotein (DSPP) mRNA expression in odontobalstic layer was also examined by LCM. Teeth cultured following saline-perfusion and nonperfusion served as cultured controls. Normal teeth also served as noncultured controls. Histological examination demonstrated that the structure of the pulp tissue was well preserved in the medium-perfused explants in contrast to the cultured control groups. The Class II MHC, IL-6, and p53 mRNA expression levels of ED2-positive cells and DSPP expression levels of odontoblastic layer tissues in the pulp of medium-perfused explants were not significantly different from those in the noncultured normal teeth. In conclusion, the structural integrity and mRNA expression in the pulp were maintained at the in vivo level in the ex vivo whole tooth-in-jaw-bone culture system. The system may lay the foundation for studies aiming at defining further histological and molecular mechanism of the pulp. Copyright © 2012 Wiley Periodicals, Inc.

Effects of pulpectomy on the amount of root resorption during orthodontic tooth movement.

PubMed

Kaku, Masato; Sumi, Hiromi; Shikata, Hanaka; Kojima, Shunichi; Motokawa, Masahide; Fujita, Tadashi; Tanimoto, Kotaro; Tanne, Kazuo

2014-03-01

Previous studies have revealed that orthodontic force affects dental pulp via the rupture of blood vessels and vacuolization of pulp tissues. We hypothesized that pulp tissues express inflammatory cytokines and regulators of odontoclast differentiation after excess orthodontic force. The purpose of this study was to investigate the effects of tensile force in human pulp cells and to measure inflammatory root resorption during tooth movement in pulpless rat teeth. After cyclic tensile force application in human pulp cells, gene expression and protein concentration of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand, interleukin-1 beta, and tumor necrosis factor alpha were determined by real-time polymerase chain reaction and enzyme-linked immunoassay. Moreover, the role of the stretch-activated channel was evaluated by gadolinium (Gd(3+)) treatment. The upper right first molars of 7-week Wistar rats were subjected to pulpectomy and root canal filling followed by mesial movement for 6 months. The expression of cytokine messenger RNAs and proteins in the experimental group peaked with loading at 10-kPa tensile force after 48 hours (P < .01). Gd(3+) reduced the expression of these cytokine messenger RNAs and protein concentrations (P < .01). The amount of inflammatory root resorption was significantly larger in the control teeth than the pulpectomized teeth (P < .05). This study shows that tensile forces in the pulp cells enhance the expression of various cytokines via the S-A channel, which may lead to inflammatory root resorption during tooth movement. It also suggests that root canal treatment is effective for progressive severe inflammatory root resorption during tooth movement. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Three-body wear of resin denture teeth with and without nanofillers.

PubMed

Stober, Thomas; Henninger, Moritz; Schmitter, Marc; Pritsch, Maria; Rammelsberg, Peter

2010-02-01

The wear behavior of newly developed denture teeth with nanofillers may be different from teeth with other chemical formulations. The purpose of this study was to examine the 3-body wear resistance of 11 different commercially available resin denture teeth. The materials tested were conventional (SR Orthotyp PE, Orthognath) and cross-linked acrylic resin teeth without inorganic fillers (Premium 8, SR Postaris DCL, Trubyte Portrait, Artiplus), composite resin teeth with inorganic fillers (SR Orthosit PE, Vitapan), and composite resin teeth (experimental materials) with inorganic nanofillers (NC Veracia Posterior, e-Ha, Mondial). Human enamel and a ceramic denture tooth (Lumin Vacuum) were used as reference materials. The 3-body wear test was performed in a wear machine developed by the Academic Center for Dentistry Amsterdam (ACTA), with millet suspension acting as an abrasive medium (n=10, test load: 15 N, slip rate: 20%, number of cycles: 100,000). Wear was determined with the aid of a profilometer. Data were analyzed with the Kruskal-Wallis test and Mann-Whitney U test using the closed testing approach (significance level for familywise error rate, alpha=.05). None of the acrylic and composite resin materials tested in this study demonstrated the 3-body wear resistance of ceramic teeth or human enamel. Teeth with inorganic fillers demonstrated significantly lower wear values than conventional or cross-linked acrylic resin teeth without fillers. Composite resin teeth with traditional fillers showed significantly lower wear than composite resin teeth with nanofillers. Denture teeth with and without inorganic fillers differed significantly with regard to the degree of wear generated in the ACTA wear simulator. The incorporation of nanofillers did not improve the wear resistance compared to teeth with traditional fillers.

Wisdom teeth: mankind's future third vice-teeth?

PubMed

Zou, DuoHong; Zhao, Jun; Ding, WangHui; Xia, LunGuo; Jang, XinQuan; Huang, YuanLiang

2010-01-01

The third molar teeth (wisdom teeth) represent the last eruption of the teeth in the human dentition. Throughout evolution, the mandible has had a tendency to decrease in size; the third molar teeth are often impacted, resulting in incomplete tooth eruption that often causes clinical pericoronitis, dental caries, and pericemental abscess. Therefore, the wisdom teeth are often extracted. Moreover, wisdom teeth are often removed for clinical orthodontic treatment. On the other hand, tooth loss due to periodontal disease, dental caries, trauma, or a variety of genetic disorders continues to affect people's lives. Autologous tissues for dental tissue regeneration that could replace lost teeth could provide a vital alternative to currently available clinical treatments. To pursue this goal, we hypothesize that human third molar tooth buds can be obtained during development. Human wisdom tooth germination tissue could then be placed into an embryonic stem cell bank for storage. When the donor's other teeth are missing, embryonic stem cell and tissue engineering technologies, will permit the restoration of the missing teeth. Therefore wisdom teeth will be mankind's future third vice-teeth.

The effect of pregnancy and lactation on bone mineral density in fluoride-exposed rats.

PubMed

Yildiz, Mustafa; Oral, Baha

2006-06-01

Fluoride increases metabolic turnover of the bone in favour of bone formation. Excessive intake of fluoride may lead to pathological changes in teeth and bones: dental and skeletal fluorosis. In this study, we investigated the effect of pregnancy and lactation on bone mineral density (BMD) in fluoride-exposed rats. Female Wistar rats were given commercially available spring water with 100 ppm fluoride (N = 8), or without addition (N = 8) for 18 weeks. At 16 weeks of age, four female rats and one male rat were kept in a cage for 5 days; all females were successfully impregnated. BMD was measured at 16 weeks of age, on the first day postpartum, and at the end of lactation. Spinal BMD was significantly higher in fluoride-exposed rats than control (P < 0.05), but there were no differences in femoral BMD (P = 0.670). During pregnancy, spinal BMD and femoral BMD were not significantly changed in fluoride-exposed rats, whereas BMD of the spine was significantly decreased in the control rats (P = 0.013), but not in the femur. During lactation, BMD was significantly decreased at the two regions compared to initial values (P < 0.05) in both groups. This study shows that pregnancy has no effect on bone, but lactation has a decreasing effect on BMD in fluoride-exposed rats.

Fibrin gel improves tissue ingrowth and cell differentiation in human immature premolars implanted in rats.

PubMed

Ruangsawasdi, Nisarat; Zehnder, Matthias; Weber, Franz E

2014-02-01

In pulpless immature human premolars implanted in rodents, this study investigated whether fibrin gel offered advantages over leaving the root canal empty regarding soft tissue ingrowth and cell differentiation. Root canals of extracted human immature premolars (n = 12) were accessed and then irrigated with 5% sodium hypochlorite followed by 17% ethylenediaminetetraacetic acid. Root canals were then either left empty or filled with a fibrin gel (n = 6 each) before being placed subcutaneously on top of the calvarial bone of rats (1 tooth per rat) for 12 weeks. After sacrifice, teeth were histologically assessed. Tissue ingrowth was quantified and compared between groups using the Mann-Whitney U test (P < .05). Cells adhering to the pulp canal wall were immunohistochemically screened for the presence of bone sialoprotein (BSP) and dentin sialoprotein (DSP). More tissue grew into the pulp space when teeth were filled with fibrin gel (P < .05). The presence of fibrin gel affected not only the extent of tissue ingrowth but also tissue morphology and differentiation of cells contacting the dentinal wall. In the fibrin gel group, newly formed tissue was similar to normal pulp, constituted of inner pulp, cell-rich zone, cell-free zone, and an apparent odontoblast layer, which stained positive for BSP and DSP. Newly formed blood vessels were also more abundant compared with the initially empty root canals. Under the conditions of this study, fibrin gel improved cell infiltration and cell-dentin interaction. Both are necessary for pulp tissue regeneration. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Immunodetection of osteoadherin in murine tooth extracellular matrices.

PubMed

Couble, Marie-Lise; Bleicher, Françoise; Farges, Jean-Christophe; Peyrol, Simone; Lucchini, Marion; Magloire, Henry; Staquet, Marie-Jeanne

2004-01-01

An antiserum was generated from synthetic peptides highly conserved between different mammalian species to immunolocalise the small leucine-rich proteoglycan osteoadherin (OSAD) in murine teeth. In 19-day-old embryos of rats and mice, a positive staining was found in incisor predentin and alveolar bone surrounding developing incisors and molars. In newborns, OSAD was detected at the tip of the first molar cusp where it accumulated in predentin concomitantly with odontoblast differentiation. In 2-day-old rats and mice, in the first molar, immunostaining revealed positive predentin, enamel matrix close to the apical pole of ameloblasts and a strong signal in dentin. At this stage, OSAD was detected in predentin in the second molar. Ultrastructural immunocytochemistry showed gold particles associated with collagen fibres in predentin and in foci at the dentin mineralisation front. Gold particles were also detected near the secretory pole of ameloblasts where enamel crystallites elongate. No staining was detected in pulp tissue and dental follicle. Restriction of OSAD expression to the extracellular matrix of bone, dentin and enamel suggests a role of this proteoglycan in the organisation of mineralised tissues.

The effects of an anchovy (stolephorus insularis) substrate application on the level of fluor intrusion on Sprague Dawley rat teeth (in vivo)

NASA Astrophysics Data System (ADS)

Sakinah, N. R.; Gunawan, H. A.; Puspitawati, R.

2017-08-01

Fluoride intrusion is one of the efficacy parameters of fluoridation. Anchovy (Stolephorus insularis), which contains a high fluoride concentration in the CaF2compound, can be used as a fluoridative agent which is affordable and easily obtained. The aim of this study is to prove the effectiveness of the application of an anchovy substrate (Stolephorus insularis), either by a feeding method or a topical method, for tooth fluoridation based on the depth of fluoride intrusion on the enamel. An in vivo experimental laboratory method was used. The subjects were 14 Sprague Dawley rats divided into five groups. The groups included a baseline control, a feeding negative control, a topical negative control, an anchovy feeding method, and a topical solution anchovy method. After 15 days of treatment, the teeth were cut transversely with a 0.5 mm thickness then processed to test for fluoride intrusion using fluorescence microscopy. There was increased fluor intrusion on the enamel of the experimental groups compared to the negative control groups (p<0.05).Fluoride intrusion using the topical fluoride method is higher than with the feeding method (p <0.05). Thus, the application of an anchovy substrate, either by chewing or smearing, increases fluoride intrusion on the enamel.

The creation of virtual teeth with and without tooth pathology for a virtual learning environment in dental education.

PubMed

de Boer, I R; Wesselink, P R; Vervoorn, J M

2013-11-01

To describe the development and opportunities for implementation of virtual teeth with and without pathology for use in a virtual learning environment in dental education. The creation of virtual teeth begins by scanning a tooth with a cone beam CT. The resulting scan consists of multiple two-dimensional grey-scale images. The specially designed software program ColorMapEditor connects these two-dimensional images to create a three-dimensional tooth. With this software, any aspect of the tooth can be modified, including its colour, volume, shape and density, resulting in the creation of virtual teeth of any type. This article provides examples of realistic virtual teeth with and without pathology that can be used for dental education. ColorMapEditor offers infinite possibilities to adjust and add options for the optimisation of virtual teeth. Virtual teeth have unlimited availability for dental students, allowing them to practise as often as required. Virtual teeth can be made and adjusted to any shape with any type of pathology. Further developments in software and hardware technology are necessary to refine the ability to colour and shape the interior of the pulp chamber and surface of the tooth to enable not only treatment but also diagnostics and thus create a greater degree of realism. The creation and use of virtual teeth in dental education appears to be feasible but is still in development; it offers many opportunities for the creation of teeth with various pathologies, although an evaluation of its use in dental education is still required. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enamel mineral concentration in diabetic rodents.

PubMed

Atar, M; Davis, G R; Verry, P; Wong, F S L

2007-12-01

This was to use x-ray microtomography (XMT), to assess the mineral composition and 3-D structure of enamel and bone in the teeth and skulls of diabetic rodents. Three-dimensional images of the skull were reconstructed using computer generated false colour to highlight different levels of mineralization in bone and enamel. These showed that diabetic rodents exhibited more wear in their teeth. Deformities were observed in the alveolar process of the mandible and maxilla. Regions of extensive hypomineralization were found in the calvarial bone of skulls. The maximum mineral concentrations and the time constants for diabetic rodents were similar to the controls. The diabetic mice appeared to have random regions of hypomineralization and one diabetic rat had areas of hypoplasia in the mandibular incisors. Diabetes may have a detrimental influence on the function of ameloblasts in laying down enamel.

An analysis of the timing and materials associated with pulp disease following restorative dental treatment.

PubMed

Yong, J B; Sivarajan, S; Abbott, P V

2018-05-19

To assess whether the timing of pulp disease after tooth restoration was associated with type of restorative dental material used, extent of the restoration, or tooth type. A comprehensive search and analysis of data using the Titanium Oral Health Management software program at The Oral Health Centre of Western Australia was performed to correlate procedural codes for teeth that had restorations placed and subsequently developed pulp disease requiring endodontic treatment or extraction from 1 st January 2009 to 31 st December 2013. Manual analysis of paper and/or electronic patient record cards was also performed. Data collected included restoration type, restored tooth surfaces, tooth type, and the dates of restoration and subsequent endodontic intervention or extraction. Of 330 teeth that met the inclusion criteria, 84 (26%) had composite resin restorations, 80 (24%) had amalgams, 119 (36%) had GICs and 47 (14%) had crowns. The average time between restoration and further intervention was 330 days with a range from 3 days to 1,775 days (approx. 5 years). Teeth restored with crowns or five-surface restorations were significantly more likely to require earlier intervention than other restorations. Premolar and anterior teeth were also more likely to require earlier intervention. Teeth that developed pulp disease requiring further intervention that were restored with crowns and five-surface GIC developed the disease sooner than teeth that were restored with amalgam or composite. In teeth with five surface restorations that developed pulp disease requiring further intervention, premolar and anterior teeth developed the pulp disease sooner than molars. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Evolutionary aspects of the development of teeth and baleen in the bowhead whale.

PubMed

Thewissen, J G M; Hieronymus, Tobin L; George, John C; Suydam, Robert; Stimmelmayr, Raphaela; McBurney, Denise

2017-04-01

In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food-collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF-4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF-4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes. © 2017 Anatomical Society.

Fluorescence properties of human teeth and dental calculus for clinical applications

NASA Astrophysics Data System (ADS)

Lee, Yong-Keun

2015-04-01

Fluorescent emission of human teeth and dental calculus is important for the esthetic rehabilitation of teeth, diagnosis of dental caries, and detection of dental calculus. The purposes of this review were to summarize the fluorescence and phosphorescence of human teeth by ambient ultraviolet (UV) light, to investigate the clinically relevant fluorescence measurement methods in dentistry, and to review the fluorescence of teeth and dental calculus by specific wavelength light. Dentine was three times more phosphorescent than enamel. When exposed to light sources containing UV components, the fluorescence of human teeth gives them the quality of vitality, and fluorescent emission with a peak of 440 nm is observed. Esthetic restorative materials should have fluorescence properties similar to those of natural teeth. Based on the fluorescence of teeth and restorative materials as determined with a spectrophotometer, a fluorescence parameter was defined. As to the fluorescence spectra by a specific wavelength, varied wavelengths were investigated for clinical applications, and several methods for the diagnosis of dental caries and the detection of dental calculus were developed. Since fluorescent properties of dental hard tissues have been used and would be expanded in diverse fields of clinical practice, these properties should be investigated further, embracing newly developed optical techniques.

Fluorescence properties of human teeth and dental calculus for clinical applications.

PubMed

Lee, Yong-Keun

2015-04-01

Fluorescent emission of human teeth and dental calculus is important for the esthetic rehabilitation of teeth, diagnosis of dental caries, and detection of dental calculus. The purposes of this review were to summarize the fluorescence and phosphorescence of human teeth by ambient ultraviolet (UV) light, to investigate the clinically relevant fluorescence measurement methods in dentistry, and to review the fluorescence of teeth and dental calculus by specific wavelength light. Dentine was three times more phosphorescent than enamel. When exposed to light sources containing UV components, the fluorescence of human teeth gives them the quality of vitality, and fluorescent emission with a peak of 440 nm is observed. Esthetic restorative materials should have fluorescence properties similar to those of natural teeth. Based on the fluorescence of teeth and restorative materials as determined with a spectrophotometer, a fluorescence parameter was defined. As to the fluorescence spectra by a specific wavelength, varied wavelengths were investigated for clinical applications, and several methods for the diagnosis of dental caries and the detection of dental calculus were developed. Since fluorescent properties of dental hard tissues have been used and would be expanded in diverse fields of clinical practice, these properties should be investigated further, embracing newly developed optical techniques.

Failure of tooth eruption in two patients with cerebral palsy and bruxism-a 10-year follow-up: a case report.

PubMed

Staufer, Kirsten; Hamadeh, Sinan; Gesch, Dietmar

2009-01-01

The aim of this paper was to analyze delayed tooth eruption in two children with cerebral palsy who had severe bruxism and to determine whether treatment could influence tooth eruption and alignment. Extraction of primary teeth was carried out and orthodontic treatment was considered due to severe tooth wear of primary teeth, lack of space, and development of a class III malocclusion. Analysis was based on clinical examination, photographs, radiographs, and dental casts. In both patients, early mixed dentition was delayed for more than 5 years. Calcification and root development of posterior permanent teeth corresponded with the chronological age. Root resorption of the severely abraded primary teeth and eruption of their successors were delayed or failed. Eruption of permanent teeth occurred slowly after primary teeth were extracted. Orthodontic treatment succeeded in one patient, achieving a normal overjet in combination with a successful orofacial therapy. The disturbed exfoliation of abraded primary teeth and failure of tooth eruption of the posterior teeth could be linked to the systemic pathology and to bruxism. At age 20, eruption of the canines and premolars remained questionable.

Image-Based 3d Reconstruction and Analysis for Orthodontia

NASA Astrophysics Data System (ADS)

Knyaz, V. A.

2012-08-01

Among the main tasks of orthodontia are analysis of teeth arches and treatment planning for providing correct position for every tooth. The treatment plan is based on measurement of teeth parameters and designing perfect teeth arch curve which teeth are to create after treatment. The most common technique for teeth moving uses standard brackets which put on teeth and a wire of given shape which is clamped by these brackets for producing necessary forces to every tooth for moving it in given direction. The disadvantages of standard bracket technique are low accuracy of tooth dimensions measurements and problems with applying standard approach for wide variety of complex orthodontic cases. The image-based technique for orthodontic planning, treatment and documenting aimed at overcoming these disadvantages is proposed. The proposed approach provides performing accurate measurements of teeth parameters needed for adequate planning, designing correct teeth position and monitoring treatment process. The developed technique applies photogrammetric means for teeth arch 3D model generation, brackets position determination and teeth shifting analysis.

Postprocedural problems in an overdenture population: a longitudinal study.

PubMed

Ettinger, Ronald L; Qian, Fang

2004-05-01

This study reports on endodontic and other post-procedural problems experienced by overdenture patients from 1973 to 1996. There were 395 subjects enrolled in the study; 273 fulfilled the recall criteria. At recall, all subjects were examined by a single examiner, and appropriate maintenance care was performed. The 273 subjects had 666 abutments and 626 endodontically treated teeth; of these, 51 subjects had postprocedural problems in 81 teeth. Thus, 87.1% of the endodontically treated teeth had no postprocedural problems, and 12.9% had postprocedural problems. Of the subpopulation with postprocedural problems, the most common problem was endodontically treated teeth developing periradicular lesions (37.0%) because of recurrent caries causing loss of the restoration sealing the root canal. Twenty of the 30 teeth were successfully retreated. The next most common problem was vertical root fractures (30.9%), followed by vital teeth developing periradicular lesions (19.8%). Most of the failures could have been prevented by better oral hygiene. Vertical root fractures were statistically associated with abutments in the maxilla and opposed by natural teeth; protection of these abutments with thimble crowns could prevent fractures.

A simple method for accurate endotracheal placement of an intubation tube in Guinea pigs to assess lung injury following chemical exposure.

PubMed

Nambiar, M P; Gordon, R K; Moran, T S; Richards, S M; Sciuto, A M

2007-01-01

ABSTRACT Guinea pigs are considered as the animal model of choice for toxicology and medical countermeasure studies against chemical warfare agents (CWAs) and toxic organophosphate pesticides because of the low levels of carboxylesterase compared to rats and mice. However, it is difficult to intubate guinea pigs without damaging the larynx to perform CWA inhalation experiments. We describe an easy technique of intubation of guinea pigs for accurate endotracheal placement of the intubation tube. The technique involves a speculum made by cutting the medium-size ear speculum in the midline leaving behind the intact circular connector to the otoscope. Guinea pigs were anesthetized with Telazol/meditomidine, the tongue was pulled using blunt forceps, and an otoscope attached with the specially prepared speculum was inserted gently. Insertion of the speculum raises the epiglottis and restrains the movements of vocal cord, which allows smooth insertion of the metal stylet-reinforced intubation tube. Accurate endotracheal placement of the intubation tube was achieved by measuring the length from the tracheal bifurcation to vocal cord and vocal cord to the upper front teeth. The average length of the trachea in guinea pigs (275 +/- 25 g) was 5.5 +/- 0.2 cm and the distance from the vocal cord to the front teeth was typically 3 cm. Coinciding an intubation tube marked at 6 cm with the upper front teeth accurately places the intubation tube 2.5 cm above the tracheal bifurcation. This simple method of intubation does not disturb the natural flora of the mouth and causes minimum laryngeal damage. It is rapid and reliable, and will be very valuable in inhalation exposure to chemical/biological warfare agents or toxic chemicals to assess respiratory toxicity and develop medical countermeasures.

Evaluation of antibacterial and remineralizing nanocomposite and adhesive in rat tooth cavity model

PubMed Central

Li, Fang; Wang, Ping; Weir, Michael D.; Fouad, Ashraf F.; Xu, Hockin H. K.

2014-01-01

Antibacterial and remineralizing dental composites and adhesives were recently developed to inhibit biofilm acids and combat secondary caries. It is not clear what effect these materials will have on dental pulps in vivo. The objectives of this study were to investigate the antibacterial and remineralizing restorations in a rat tooth cavity model, and determine pulpal inflammatory response and tertiary dentin formation. Nanoparticles of amorphous calcium phosphate (NACP) and antibacterial dimethylaminododecyl methacrylate (DMADDM) were synthesized and incorporated into a composite and an adhesive. Occlusal cavities were prepared in the first molars of rats and restored with four types of restoration: Control composite and adhesive; control plus DMADDM; control plus NACP; and control plus both DMADDM and NACP. At 8 or 30 days (d), rat molars were harvested for histological analysis. For inflammatory cell response, regardless of time periods, NACP group and DMADDM+NACP group showed lower scores (better biocompatibility) than control group (p = 0.014 for 8 d, p = 0.018 for 30 d). For tissue disorganization, NACP and DMADDM+NACP had better scores than control (p = 0.027) at 30 d. At 8 d, restorations containing NACP had tertiary dentin thickness (TDT) that was 5-6 fold that of control. At 30 d, restorations containing NACP had TDT that was 4-6 fold that of control. In conclusion, novel antibacterial and remineralizing restorations were tested in rat teeth in vivo for the first time. Composite and adhesive containing NACP and DMADDM exhibited milder pulpal inflammation and much greater tertiary dentin formation, than control adhesive and composite. Therefore, the novel composite and adhesive containing NACP and DMADDM are promising as a new therapeutic restorative system to not only combat oral pathogens and biofilm acids as shown previously, but also facilitate the healing of the dentin-pulp complex. PMID:24583320

Use of hyperdry amniotic membrane in operations for cleft palate: a study in rats.

PubMed

Tsuno, Hiroaki; Noguchi, Makoto; Okabe, Motonori; Tomihara, Kei; Yoshida, Toshiko; Nikaido, Toshio

2015-04-01

The growth of maxillary bone and the development of dentition are often impaired in patients who have had pushback operations for repair of a cleft palate. There has been considerable discussion about the most suitable technique or material used in such repairs to resolve the problem. Hyperdry amniotic membrane, a new preservable material derived from human amnion, has recently been introduced in several procedures. We have evaluated its use during pushback surgery in animal studies to try to correct the inhibition of growth and development of the maxilla. Mucosal defects were created in 3-week-old rats, and then covered with hyperdry amniotic membrane or not. Healing was assessed by histological and morphological examination at 1 week and 7 weeks postoperatively. In the group treated with hyperdry amniotic membrane, submucosal tissue was reconstructed successfully during the early postoperative period. Lateral palatal growth was not inhibited as much, and medial inclination of the teeth was less, after a period of growth using this material. The results suggest that hyperdry amniotic membrane is a suitable new dressing material for use in the treatment of cleft palate. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Non-syndromic multiple supernumerary teeth in permanent dentition: a rare phenomenon

PubMed Central

Yadav, Rakesh Kumar; Rao, Jitendra; Yadav, Lakhya; Hasija, Mukesh

2013-01-01

Hyperdontia or supernumerary teeth in the absence of associated systemic condition or syndrome is an uncommon phenomenon. Non-syndromic supernumerary teeth need to have periodical radiographic observation. In the case of asymptomatic condition, as they impacted in the jaw, a careful examination is necessary because they may develop into pathological status such as dentigerous cysts. Surgical removal of such teeth is indicated if evidence of any pathologies, such as cystic lesion, resorption, delayed eruption, altered eruption and displacement of adjacent teeth, is evident or have occurred. PMID:23704431

The development of complex tooth shape in reptiles

PubMed Central

Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S.

2014-01-01

Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus

NASA Astrophysics Data System (ADS)

Chen, Donglei; Blom, Henning; Sanchez, Sophie; Tafforeau, Paul; Märss, Tiiu; Ahlberg, Per E.

2017-05-01

The numerous cushion-shaped tooth-bearing plates attributed to the stem group osteichthyan Lophosteus superbus, which are argued here to represent an early form of the osteichthyan inner dental arcade, display a previously unknown and presumably primitive mode of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional reconstruction from propagation phase-contrast synchrotron microtomography (PPC-SRµCT) reveals remnants of the first-generation teeth embedded in the basal plate, a feature never previously observed in any taxon. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth at the growing edge of the plate. The first generation of teeth is thus diachronous. Successor teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus, the replacement tooth buds cannot have been generated by a single permanent dental lamina at the lingual edge of the tooth cushion, but must have arisen either from successional dental laminae associated with the individual predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement.

An Ancient Gene Network Is Co-opted for Teeth on Old and New Jaws

PubMed Central

Fraser, Gareth J; Hulsey, C. Darrin; Bloomquist, Ryan F; Uyesugi, Kristine; Manley, Nancy R; Streelman, J. Todd

2009-01-01

Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Much later in evolutionary time, teleost fishes evolved a novel toothed jaw in the pharynx, the location of the first vertebrate teeth. To examine the evolutionary modularity of dentitions, we asked whether oral and pharyngeal teeth develop using common or independent gene regulatory pathways. First, we showed that tooth number is correlated on oral and pharyngeal jaws across species of cichlid fishes from Lake Malawi (East Africa), suggestive of common regulatory mechanisms for tooth initiation. Surprisingly, we found that cichlid pharyngeal dentitions develop in a region of dense hox gene expression. Thus, regulation of tooth number is conserved, despite distinct developmental environments of oral and pharyngeal jaws; pharyngeal jaws occupy hox-positive, endodermal sites, and oral jaws develop in hox-negative regions with ectodermal cell contributions. Next, we studied the expression of a dental gene network for tooth initiation, most genes of which are similarly deployed across the two disparate jaw sites. This collection of genes includes members of the ectodysplasin pathway, eda and edar, expressed identically during the patterning of oral and pharyngeal teeth. Taken together, these data suggest that pharyngeal teeth of jawless vertebrates utilized an ancient gene network before the origin of oral jaws, oral teeth, and ectodermal appendages. The first vertebrate dentition likely appeared in a hox-positive, endodermal environment and expressed a genetic program including ectodysplasin pathway genes. This ancient regulatory circuit was co-opted and modified for teeth in oral jaws of the first jawed vertebrate, and subsequently deployed as jaws enveloped teeth on novel pharyngeal jaws. Our data highlight an amazing modularity of jaws and teeth as they coevolved during the history of vertebrates. We exploit this diversity to infer a core dental gene network, common to the first tooth and all of its descendants. PMID:19215146

Continuous tooth generation in mouse is induced by activated epithelial Wnt/β-catenin signaling

PubMed Central

Järvinen, Elina; Salazar-Ciudad, Isaac; Birchmeier, Walter; Taketo, Makoto M.; Jernvall, Jukka; Thesleff, Irma

2006-01-01

The single replacement from milk teeth to permanent teeth makes mammalian teeth different from teeth of most nonmammalian vertebrates and other epithelial organs such as hair and feathers, whose continuous replacement has been linked to Wnt signaling. Here we show that mouse tooth buds expressing stabilized β-catenin in epithelium give rise to dozens of teeth. The molar crowns, however, are typically simplified unicusped cones. We demonstrate that the supernumerary teeth develop by a renewal process where new signaling centers, the enamel knots, bud off from the existing dental epithelium. The basic aspects of the unlocked tooth renewal can be reproduced with a computer model on tooth development by increasing the intrinsic level of activator production, supporting the role of β-catenin pathway as an upstream activator of enamel knot formation. These results may implicate Wnt signaling in tooth renewal, a capacity that was all but lost when mammals evolved progressively more complicated tooth shapes. PMID:17121988

Possible Ni-Rich Mafic-Ultramafic Magmatic Sequence in the Columbia Hills: Evidence from the Spirit Rover

NASA Technical Reports Server (NTRS)

Mittlefehldt, David W.; Gellert, R.; McCoy, T.; McSween, H. Y., Jr.; Li, R.

2006-01-01

The Spirit rover landed on geologic units of Hesperian age in Gusev Crater. The Columbia Hills rise above the surrounding plains materials, but orbital images show that the Columbia Hills are older [1, 2]. Spirit has recently descended the southeast slope of the Columbia Hills doing detailed measurements of a series of outcrops. The mineralogical and compositional data on these rocks are consistent with an interpretation as a magmatic sequence becoming increasingly olivine-rich down slope. The outcrop sequence is Larry s Bench, Seminole, Algonquin and Comanche. The "teeth" on the Rock Abrasion Tool (RAT) wore away prior to arrival at Larry s Bench; the data discussed are for RAT brushed surfaces.

Effects of tung oil on salivary viscosity and extent and incidence of dental caries in rats.

PubMed

Biesbrock, A R; Dirksen, T; Schuster, G

1992-01-01

Increased salivary viscosity may be associated with an increase in dental caries. In order to examine this relationship, the caries level in rats was monitored following gastric intubation with tung oil which has been shown to significantly increase salivary viscosity. Tung oil intubation over an 8-week period significantly increased the salivary viscosity in rats as compared with deoinized water and corn oil intubation. The total number of carious lesions was significantly increased (p less than 0.05) in the tung oil intubated rats as compared with the two other groups. This increase in carious lesions was primarily associated with the smooth surfaces of the teeth. There was also a significant increase (p less than 0.05) in the extent of enamel and dentin involvement of the tung oil intubated rats as compared with the other two groups. Histologic examination of the submandibular glands revealed an increase in the amount of glycoprotein material in the convoluted granular tubules of the tung oil intubated rats as compared with the deionized water and corn oil intubated animals. Collectively, these results suggest that tung oil intubation is correlated with both increased salivary viscosity and increased smooth-surface dental caries, suggesting that the viscosity may be related to dental caries progression.

Dry socket: incidence, clinical features, and predisposing factors.

PubMed

Akinbami, Babatunde O; Godspower, Thikan

2014-01-01

Background. Dry socket is a global phenomenon. The purpose of the study was to investigate the incidence of dry socket in recent times in a Nigerian Tertiary Hospital. Methods. Patients who were referred for dental extractions were included in the study. The case files of patients were obtained and information retrieved included biodata, indication for extraction, number and type of teeth extracted, oral hygiene status, compliance to oral hygiene instructions, and development of dry socket. Results. One thousand, one hundred and eighty two patients with total of 1362 teeth extracted during the 4-year period of the study were analyzed, out of which 1.4% teeth developed dry socket. The mean age (SD) was 35.2 (16.0) years. Most of the patients who presented with dry socket were in the fourth decade of life. Mandibular teeth were affected more than maxillary teeth. Molars were more affected. Retained roots and third molars were conspicuous in the cases with dry socket. Conclusion. The incidence of dry socket in our centre was lower than previous reports. Oral hygiene status, lower teeth, and female gender were significantly associated with development of dry socket. Treatment with normal saline irrigation and ZnO eugenol dressings allowed relief of the symptoms.

Dry Socket: Incidence, Clinical Features, and Predisposing Factors

PubMed Central

Akinbami, Babatunde O.; Godspower, Thikan

2014-01-01

Background. Dry socket is a global phenomenon. The purpose of the study was to investigate the incidence of dry socket in recent times in a Nigerian Tertiary Hospital. Methods. Patients who were referred for dental extractions were included in the study. The case files of patients were obtained and information retrieved included biodata, indication for extraction, number and type of teeth extracted, oral hygiene status, compliance to oral hygiene instructions, and development of dry socket. Results. One thousand, one hundred and eighty two patients with total of 1362 teeth extracted during the 4-year period of the study were analyzed, out of which 1.4% teeth developed dry socket. The mean age (SD) was 35.2 (16.0) years. Most of the patients who presented with dry socket were in the fourth decade of life. Mandibular teeth were affected more than maxillary teeth. Molars were more affected. Retained roots and third molars were conspicuous in the cases with dry socket. Conclusion. The incidence of dry socket in our centre was lower than previous reports. Oral hygiene status, lower teeth, and female gender were significantly associated with development of dry socket. Treatment with normal saline irrigation and ZnO eugenol dressings allowed relief of the symptoms. PMID:24987419

Supernumerary Teeth in the Maxillary Anterior Region: The Dilemma of Early Versus Late Surgical Intervention.

PubMed

Sarne, Ofer; Shapira, Yehoshua; Blumer, Sigalit; Finkelstein, Tamar; Schonberger, Shirley; Bechor, Naomi; Shpack, Nir

Supernumerary teeth are the most common developmental dental anomalies in the maxillary anterior region causing interference to the developing permanent incisors resulting in poor dental and facial esthetics. Two different opinions regarding the timing for surgical removal of the supernumerary teeth are presented. In this case report, three brothers with supernumerary teeth in the maxillary anterior region are presented, their surgical and orthodontic management and outcome are discussed.

Histologic Outcomes of Uninfected Human Immature Teeth Treated with Regenerative Endodontics: 2 Case Reports.

PubMed

Nosrat, Ali; Kolahdouzan, Alireza; Hosseini, Farzaneh; Mehrizi, Ehsan A; Verma, Prashant; Torabinejad, Mahmoud

2015-10-01

A growing body of evidence exists showing the possibility of growing vital tissues in the root canal spaces of teeth with necrotic pulps and open apices. However, there is very limited histologic information regarding characteristics of tissues formed in the root canal space of human teeth after regenerative endodontics. The aim of this study was to examine clinically and histologically the outcomes of human immature teeth treated with regenerative endodontics. Two healthy birooted human maxillary first premolar teeth scheduled for extraction were included. Preoperative radiographs confirmed that these teeth had immature apices. Vitality tests showed the presence of vital pulps in these teeth. After receiving consent forms, the teeth were isolated with a rubber dam, and the pulps were completely removed. After the formation of blood clots in the canals, the teeth were covered with mineral trioxide aggregate. Four months later, the teeth were clinically and radiographically evaluated, extracted, and examined histologically. Both patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. Histologic examination of tissues growing into the root canal space of these teeth shows the presence of connective tissue, bone and cementum formation, and thickening of roots. Based on our findings, it appears that when canals of teeth with open apices are treated with regenerative endodontics, tissues of the periodontium grow into the root canals of these teeth. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Regional early development and eruption of permanent teeth: case report.

PubMed

Al Mullahi, A M; Bakathir, A; Al Jahdhami, S

2017-02-01

Early development and eruption of permanent teeth are rarely reported in scientific literature. Early eruption of permanent teeth has been reported to occur due to local factors such as trauma or dental abscesses in primary teeth, and in systemic conditions. Congenital diffuse infiltrating facial lipomatosis (CDIFL) is a rare condition that belongs to a group of lipomatosis tumours. In this disorder, the mature adipocytes invade adjacent soft and hard tissues in the facial region. Accelerated tooth eruption is one of the dental anomalies associated with CDIFL. A 3-year-old boy presented with a swelling of the lower lip localised early development and eruption of permanent teeth and dental caries involving many primary teeth. The planned treatment included biopsy of the swollen lower lip to confirm the diagnosis, surgical reduction and reconstruction of lip aesthetics. The management of the carious primary teeth included preventative and comprehensive dental care and extractions. These procedures were completed under general anaesthesia due to the child's young age and poor cooperation. The lip biopsy showed features of CDIFL such as the presence of infiltrating adipose tissue, prominent number of nerve bundles and thickened vessels. The high recurrence rate of CDIFL mandates long-term monitoring during the facial growth period of the child. Follow-up care by the paediatric dentist and maxillofacial surgeon has been required to manage all aspects of this congenital malformation. This rare disorder has many implications affecting child's facial aesthetics, psychological well being, developing occlusion and risk of dental caries. A multi-disciplinary approach is needed for management of this condition.

Comparison of Gingiva, Dental Pulp, and Periodontal Ligament Cells From the Standpoint of Mesenchymal Stem Cell Properties.

PubMed

Otabe, Koji; Muneta, Takeshi; Kawashima, Nobuyuki; Suda, Hideaki; Tsuji, Kunikazu; Sekiya, Ichiro

2012-01-01

The specific properties of mesenchymal stem cells (MSCs) in oral tissues still remain unknown though their existence has been previously reported. We collected gingiva, dental pulp, and periodontal ligament tissues from removed teeth and isolated MSCs. These MSCs were compared in terms of their yields per tooth, surface epitopes, and differentiation potentials by patient-matched analysis. For in vivo calcification analysis, rat gingival and dental pulp cells mounted on β-tricalcium phospateTCP were transplanted into the perivertebral muscle of rats for 6 weeks. Gingival cells and dental pulp cells showed higher yield per tooth than periodontal ligament cells (n=6, p<0.05). Yields of periodontal ligament cells were too low for further analysis. Gingival and dental pulp cells expressed MSC markers such as CD44, CD90, and CD166. Gingival and dental pulp cells obtained phenotypes of chondrocytes and adipocytes in vitro. Approximately 60% of the colonies of gingival cells and 40% of the colonies of dental pulp cells were positively stained with alizarin red in vitro, and both gingival and dental pulp cells were calcified in vivo. We clarified properties of MSCs derived from removed teeth. We could obtain a high yield of MSCs with osteogenic potential from gingiva and dental pulp. These results indicate that gingiva and dental pulp are putative cell sources for hard tissue regeneration.

Comparison of Gingiva, Dental Pulp, and Periodontal Ligament Cells From the Standpoint of Mesenchymal Stem Cell Properties

PubMed Central

Otabe, Koji; Muneta, Takeshi; Kawashima, Nobuyuki; Suda, Hideaki; Tsuji, Kunikazu; Sekiya, Ichiro

2012-01-01

The specific properties of mesenchymal stem cells (MSCs) in oral tissues still remain unknown though their existence has been previously reported. We collected gingiva, dental pulp, and periodontal ligament tissues from removed teeth and isolated MSCs. These MSCs were compared in terms of their yields per tooth, surface epitopes, and differentiation potentials by patient-matched analysis. For in vivo calcification analysis, rat gingival and dental pulp cells mounted on β-tricalcium phospateTCP were transplanted into the perivertebral muscle of rats for 6 weeks. Gingival cells and dental pulp cells showed higher yield per tooth than periodontal ligament cells (n=6, p<0.05). Yields of periodontal ligament cells were too low for further analysis. Gingival and dental pulp cells expressed MSC markers such as CD44, CD90, and CD166. Gingival and dental pulp cells obtained phenotypes of chondrocytes and adipocytes in vitro. Approximately 60% of the colonies of gingival cells and 40% of the colonies of dental pulp cells were positively stained with alizarin red in vitro, and both gingival and dental pulp cells were calcified in vivo. We clarified properties of MSCs derived from removed teeth. We could obtain a high yield of MSCs with osteogenic potential from gingiva and dental pulp. These results indicate that gingiva and dental pulp are putative cell sources for hard tissue regeneration. PMID:26858852

Blocking VEGF signaling delays development of replacement teeth in zebrafish.

PubMed

Crucke, J; Huysseune, A

2015-01-01

The dentition in zebrafish is extremely and richly vascularized, but the function of the vasculature, in view of the continuous replacement of the teeth, remains elusive. Through application of SU5416, a vascular endothelial growth factor receptor inhibitor, we studied the role of the blood vessels in the dentition of the zebrafish. We were unable to show an effect on the development of first-generation teeth as well as first tooth replacement. However, in juvenile fish, a delay was observed in the developmental state of the replacement tooth compared with what was expected based on the maturation state of the functional tooth. Furthermore, we observed a difference between treated and nontreated fish in the distance between blood vessels and developing replacement teeth. In conclusion, our results provide support for a nutritive, rather than an inductive, function of the vasculature in the process of tooth development and replacement. © International & American Associations for Dental Research 2014.

Treatment of Mature Permanent Teeth with Necrotic Pulps and Apical Periodontitis Using Regenerative Endodontic Procedures: A Case Series.

PubMed

Saoud, Tarek Mohamed; Martin, Gabriela; Chen, Yea-Huey M; Chen, Kuang-Liang; Chen, Chao-An; Songtrakul, Kamolthip; Malek, Matthew; Sigurdsson, Asgeir; Lin, Louis M

2016-01-01

Regenerative endodontic procedures (REPs) are usually used to treat human immature permanent teeth with necrotic pulps and/or apical periodontitis. Successful REPs result in the elimination of clinical signs/symptoms, the resolution of apical periodontitis, and, in some cases, thickening of the canal walls and/or continued root development with or without apical closure. REPs can restore the vitality of tissue in the canals of immature permanent teeth previously destroyed by infection or trauma. Vital tissue is inherited with immune defense mechanisms to protect itself from foreign invaders. Recently, REPs have also been used to successfully treat human mature permanent teeth with necrotic pulps and apical periodontitis. The purpose of this case series was to present the potential of using REPs for mature permanent teeth with necrotic pulps and apical periodontitis. This case series consisted of 6 patients, 4 females and 2 males. The patients' ages ranged from 8-21 years old. Seven permanent teeth, 4 anterior and 3 molar teeth, with necrotic pulps and apical periodontitis were treated using REP. Radiographically, the root development of all teeth was almost completed except the apices of 2 molars, which showed slightly open. Complete chemomechanical debridement of the canals of the teeth was performed, and the canals were dressed with Metapaste (Meta Biomed Co, Ltd, Chungbuk, Korea) during treatment visits. Periapical bleeding into the canals was induced at the last treatment visit by placing a hand #20 or #25 K-file with the tip slightly bent through the apical foramina into the periapical tissues. A 3-mm thickness of mineral trioxide aggregate was placed into the coronal canals over semicoagulated blood. The access cavities were restored with either composite resin or amalgam. Follow-ups of the 7 teeth ranged from 8 to 26 months. The periapical lesions of 2 teeth were considered healed, and 5 teeth revealed healing. Clinical signs/symptoms were absent in all teeth at follow-up visits at different time points. None of the treated teeth responded to cold and electric pulp tests. This case series shows the potential of using REPs for mature teeth with necrotic pulp and apical periodontitis. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

[Cryopreservation of teeth].

PubMed

Zimmerli, Melanie; Filippi, Andreas

2010-01-01

After tooth loss dental implants or fixed prosthetic restorations are not indicated in children and adolescents due to incomplete maxillary and mandibular development. Cryopreservation is a method for long-term storage of healthy teeth which were removed for orthodontic reasons or due to traumatic origin. These preserved teeth can be used as autogenous replants or transplants after tooth loss. During transport to and from the freezing facilities prior to freezing the teeth are stored in a cell culture medium. The tooth is transferred into a freezing tube containing cell culture medium and cryoprotectant DMSO. Teeth autotransplanted after cryopreservation show vitality of the PDL cells. Usually no enamel and/or dentinal cracks can be observed. After tooth loss transplantation of cryopreserved teeth could be an effective and biological therapy for tooth replacement.

Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

PubMed Central

Smith, Moya Meredith

2016-01-01

The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a highly modified version of tooth replacement seen in other clades. Teeth of Squalus embryos are arranged in an alternate pattern, with successive tooth rows containing additional teeth added proximally. Asynchronous timing of tooth production along the jaw and tooth loss prior to birth cause teeth to align in oblique sets containing teeth from subsequent rows; these become parallel to the jaw margin during ontogeny, so that adult Squalus has functional tooth rows comprising obliquely stacked teeth of consecutive developmental rows. In more strongly heterodont squaliforms, initial embryonic lower teeth develop into the oblique functional sets seen in adult Squalus, with no requirement to form, and subsequently lose, teeth arranged in an initial alternate pattern. PMID:28018617

Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

NASA Astrophysics Data System (ADS)

Underwood, Charlie; Johanson, Zerina; Smith, Moya Meredith

2016-11-01

The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a highly modified version of tooth replacement seen in other clades. Teeth of Squalus embryos are arranged in an alternate pattern, with successive tooth rows containing additional teeth added proximally. Asynchronous timing of tooth production along the jaw and tooth loss prior to birth cause teeth to align in oblique sets containing teeth from subsequent rows; these become parallel to the jaw margin during ontogeny, so that adult Squalus has functional tooth rows comprising obliquely stacked teeth of consecutive developmental rows. In more strongly heterodont squaliforms, initial embryonic lower teeth develop into the oblique functional sets seen in adult Squalus, with no requirement to form, and subsequently lose, teeth arranged in an initial alternate pattern.

Flare-up rate of single-visit endodontics.

PubMed

Trope, M

1991-01-01

The purpose of the study was to compare the flare-up rate for single-visit endodontics among teeth without radiographic or clinical signs of apical periodontitis, those with radiographic or clinical signs of apical periodontitis not previously root-treated, and those with apical periodontitis where retreatment was performed. All teeth were instrumented to a predetermined minimum size with a 0.5 per cent solution of sodium hypochlorite being used as the irrigant. The root canal was obturated without regard to the presence or absence of symptoms or diagnosis of the apical condition. The patients were given written post-operative instructions and a prescription for 600 mg ibuprofen to be taken if mild to moderate pain developed. If severe pain and/or swelling developed, the patient was instructed to telephone immediately and was considered to have had a flare-up. Teeth without signs of apical periodontitis did not have any flare-ups. One flare-up occurred in 69 teeth with signs of apical periodontitis not previously root-treated. The majority of the flare-ups (3 of 22 teeth) occurred in teeth with signs of apical periodontitis requiring retreatment.

Dental age estimation in Japanese individuals combining permanent teeth and third molars.

PubMed

Ramanan, Namratha; Thevissen, Patrick; Fleuws, Steffen; Willems, G

2012-12-01

The study aim was, firstly, to verify the Willems et al. model on a Japanese reference sample. Secondly to develop a Japanese reference model based on the Willems et al. method and to verify it. Thirdly to analyze the age prediction performance adding tooth development information of third molars to permanent teeth. Retrospectively 1877 panoramic radiographs were selected in the age range between 1 and 23 years (1248 children, 629 sub-adults). Dental development was registered applying Demirjian 's stages of the mandibular left permanent teeth in children and Köhler stages on the third molars. The children's data were, firstly, used to validate the Willems et al. model (developed a Belgian reference sample), secondly, split ino a training and a test sample. On the training sample a Japanese reference model was developed based on the Willems method. The developed model and the Willems et al; model were verified on the test sample. Regression analysis was used to detect the age prediction performance adding third molar scores to permanent tooth scores. The validated Willems et al. model provided a mean absolute error of 0.85 and 0.75 years in females and males, respectively. The mean absolute error in the verified Willems et al. and the developed Japanese reference model was 0.85, 0.77 and 0.79, 0.75 years in females and males, respectively. On average a negligible change in root mean square error values was detected adding third molar scores to permanent teeth scores. The Belgian sample could be used as a reference model to estimate the age of the Japanese individuals. Combining information from the third molars and permanent teeth was not providing clinically significant improvement of age predictions based on permanent teeth information alone.

Complex patterns of tooth replacement revealed in the fruit bat (Eidolon helvum).

PubMed

Popa, Elena M; Anthwal, Neal; Tucker, Abigail S

2016-12-01

How teeth are replaced during normal growth and development has long been an important question for comparative and developmental anatomy. Non-standard model animals have become increasingly popular in this field due to the fact that the canonical model laboratory mammal, the mouse, develops only one generation of teeth (monophyodonty), whereas the majority of mammals possess two generations of teeth (diphyodonty). Here we used the straw-coloured fruit bat (Eidolon helvum), an Old World megabat, which has two generations of teeth, in order to observe the development and replacement of tooth germs from initiation up to mineralization stages. Our morphological study uses 3D reconstruction of histological sections to uncover differing arrangements of the first and second-generation tooth germs during the process of tooth replacement. We show that both tooth germ generations develop as part of the dental lamina, with the first generation detaching from the lamina, leaving the free edge to give rise to a second generation. This separation was particularly marked at the third premolar locus, where the primary and replacement teeth become positioned side by side, unconnected by a lamina. The position of the replacement tooth, with respect to the primary tooth, varied within the mouth, with replacements forming posterior to or directly lingual to the primary tooth. Development of replacement teeth was arrested at some tooth positions and this appeared to be linked to the timing of tooth initiation and the subsequent rate of development. This study adds an additional species to the growing body of non-model species used in the study of tooth replacement, and offers a new insight into the development of the diphyodont condition. © 2016 Anatomical Society.

Review of research on the mechanical properties of the human tooth

PubMed Central

Zhang, Ya-Rong; Du, Wen; Zhou, Xue-Dong; Yu, Hai-Yang

2014-01-01

‘Bronze teeth' reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties (visco-elasticity) and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth. PMID:24743065

Shaping Cutter Original Profile for Fine-module Ratchet Teeth Cutting

NASA Astrophysics Data System (ADS)

Sharkov, O. V.; Koryagin, S. I.; Velikanov, N. L.

2018-03-01

The methods for determining geometric characteristics of a theoretical original profile of the cutter for cutting ratchet teeth with a module of 0.3–1.0 mm are considered in the article. Design models describing the shaping process of cutting edges of cutter teeth are developed. Systems of expressions for determining coordinates of the points of front and back edges of cutter teeth; the workpiece angles of rotation during the cutting process; the minimum cutter radius are received. The basic data when using the proposed technique are: radii of circumferences passing through cavities of cutter teeth and external cut teeth; the gradient angle and length of straight section of the front edge of a cut tooth; angles of rotation of the cutter and the workpiece at the moment of shaping.

Autotransplantation of teeth in humans: a systematic review and meta-analysis.

PubMed

Almpani, Konstantinia; Papageorgiou, Spyridon N; Papadopoulos, Moschos A

2015-07-01

The aim of this investigation was to assess the currently available evidence concerning the complications and risk factors influencing the outcome of autotransplantation of teeth in humans. Electronic searches were conducted to identify randomized controlled and prospective clinical trials. Risk of bias within studies was assessed with the Downs and Black tool. Random-effects meta-analyses were conducted to pool the adverse event rates and relative risks with their 95% confidence intervals. Risk of bias across studies was assessed with the GRADE framework followed by sensitivity analyses. Thirty-eight studies were included in the analysis. Reported complications included the need for extraction, failure, hypermobility, pulp necrosis, pulp obliteration, and root resorption. Pooled complication event rates varied considerably, with small studies (<100 teeth) reporting greater complication rates. The analysis of risk factors was associated with both the primary outcome (extraction need) and secondary outcomes (failure, hypermobility, pulp necrosis, pulp obliteration, root resorption). The stage of root development seems to influence both the future survival, as well as the success of the transplanted teeth. Teeth with open apex were less likely to be extracted in comparison to teeth with closed apex (3 studies; 413 teeth; relative risk 0.3; 95% confidence interval 0.2-0.6). Due to the small number of the contributing studies, their methodological limitations, and the heterogeneous results reported, no firm conclusions can be drawn. Root development of the donor teeth has been established as one the most important factor related to the success of tooth autotransplantation.

Changes in the chemical composition of mineralised teeth in children after antineoplastic treatment.

PubMed

Krasuska-Sławińska, Ewa; Dembowska-Bagińska, Bożenna; Brożyna, Agnieszka; Olczak-Kowalczyk, Dorota; Czarnowska, Elżbieta; Sowińska, Agnieszka

2018-01-01

Chemotherapy, neoplasms, and their complications linked to malabsorption, malnutrition, and metabolic disorders may lead to improper tooth development and frequent severe caries in patients during/after antineoplastic treatment and to a more frequent improper tooth development in patients undergoing chemotherapy during odontogenesis. However, the causes of these abnormalities remain unknown; there are no studies on the impact of antineoplastic treatment and its complications on the chemical composition of mineralised teeth. To compare the chemical composition of mineralised teeth extracted due to complicated caries in children after chemotherapy, and of teeth extracted due to orthodontic treatment in generally healthy children. The treatment group included five teeth extracted due to complicated caries in children after antineoplastic treatment. The control group included five teeth extracted due to orthodontic treatment in generally healthy children. The chemical composition of enamel, dentine, cementum, interior of the canal, and enamel abnormalities in teeth extracted from patients after chemotherapy and in generally healthy patients were assessed with energy-dispersive X-ray spectroscopy. Results were analysed statistically. The magnesium (Mg) and zinc (Zn) mass contents in the enamel of patients after chemotherapy increased and so did the calcium (Ca) to phosphorus (P) ratio when compared to controls. Areas with abnormal enamel in patients after chemotherapy had lower concentrations of Ca and P, and higher concentrations of trace elements (Mg, Cl, and Na). The levels of the assessed elements in dentine, cementum, and inside the canal were similar in both groups of teeth.

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth

PubMed Central

Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

2014-01-01

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. PMID:25098636

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth.

PubMed

Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

2013-01-01

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. © 2013 Wiley Periodicals, Inc.

Grammomys surdaster, the Natural Host for Plasmodium berghei Parasites, as a Model to Study Whole-Organism Vaccines Against Malaria.

PubMed

Conteh, Solomon; Anderson, Charles; Lambert, Lynn; Orr-Gonzalez, Sachy; Herrod, Jessica; Robbins, Yvette L; Carter, Dariyen; Karhemere, Stomy Bin Shamamba; Pyana, Pati; Büscher, Philippe; Duffy, Patrick E

2017-04-01

AbstractInbred mice are commonly used to test candidate malaria vaccines, but have been unreliable for predicting efficacy in humans. To establish a more rigorous animal model, we acquired African woodland thicket rats of the genus Grammomys , the natural hosts for Plasmodium berghei . Thicket rats were acquired and identified as Grammomys surdaster by skull and teeth measurements and mitochondrial DNA genotyping. Herein, we demonstrate that thicket rats are highly susceptible to infection by P. berghei , and moderately susceptible to Plasmodium yoelii and Plasmodium chabaudi : 1-2 infected mosquito bites or 25-100 sporozoites administered by intravenous injection consistently resulted in patent parasitemia with P. berghei , and resulted in patent parasitemia with P. yoelii and P. chabaudi strains for at least 50% of animals. We then assessed efficacy of whole-organism vaccines to induce sterile immunity, and compared the thicket rat model to conventional mouse models. Using P. berghei ANKA radiation-attenuated sporozoites, and P. berghei ANKA and P. yoelii chemoprophylaxis vaccination approaches, we found that standard doses of vaccine sufficient to protect laboratory mice for a long duration against malaria challenge, are insufficient to protect thicket rats, which require higher doses of vaccine to achieve even short-term sterile immunity. Thicket rats may offer a more stringent and pertinent model for evaluating whole-organism vaccines.

Study on digital teeth selection and virtual teeth arrangement for complete denture.

PubMed

Yu, Xiaoling; Cheng, Xiaosheng; Dai, Ning; Chen, Hu; Yu, Changjiang; Sun, Yuchun

2018-03-01

In dentistry, the complete denture is a conventional treatment for edentulous patients. The computer-aided design and computer-aided manufacturing (CAD/CAM) has been applied on the digital complete denture which is developed rapidly. Tooth selection and arrangement is one of the most important parts in digital complete denture. In this paper, we propose a new method of personalized teeth arrangement. This paper presents a method of arranging teeth virtually for a complete denture. First, scan and extract the feature points of the 3D triangular mesh data of artificial teeth (PLY format), then establish a tooth selection system. Second, scan and mark the anatomic characteristics of the maxillary and mandibular cast surfaces, such as facial midline, the curve of the arches. With the enter information, the study calculates the common arrangement lines of artificial teeth. Third, select the preferred artificial teeth and automatically arrange them virtually in the correct position by using our own software. After that, design the gingival part of the dentures on the basic of the arranged teeth on the screen and then fabricated it by using Computerized Numerical Control (CNC) technology, Rapid Prototyping (RP) technology or 3D printer technology. Finally, select artificial teeth were embedded in wax rims. This system can choose artificial teeth reasonably and the teeth placement can meet the dentist's request to a certain extent, whereas all the operations are based on the medical principles. The study performed here involves computer sciences, medicine, and dentistry, a teeth selection system was proposed and virtual teeth arrangement was described. This study has the capacity of helping operators to select teeth, which improved the accuracy of tooth arrangement, and customized complete denture. Copyright © 2017 Elsevier B.V. All rights reserved.

Examination of extremely low frequency electromagnetic fields on orthodontic tooth movement in rats

PubMed Central

Dogru, Mehmet; Akpolat, Veysi; Dogru, Arzum Guler; Karadede, Beyza; Akkurt, Atilim; Karadede, M. Irfan

2014-01-01

The purpose of this study was to evaluate whether 50 Hz extremely low frequency electromagnetic fields (ELF-EMFs) affect the amount of orthodontic tooth movement in rats. The experiments were performed on 18 male Sprague-Dawley rats. The rats were randomly divided into three groups (n = 6): cage-control (Cg-Cnt) group (n = 6); sinusoidal electromagnetic field (SEMF) group (n = 6); and pulsed electromagnetic field (PEMF) group (n = 6). In SEMF and PEMF groups, rats were subjected to 1.5 mT EMF exposure eight hours per day for eight days. In order to obtain tooth movement, holes were drilled on the right and left maxillary central incisors of the rats at a distance 1.5–2 mm away from the gingiva and 20 g of orthodontic forces were applied to the teeth. Generated linear model for repeated measures and Bonferroni tests were used to evaluate the differences between the groups. Interactions among groups by days were found by using Pillai's trace multivariate test. The results showed that significant differences were present among the groups (F = 5.035; p = 0.03) according to the extent of tooth movement. Significant differences between the amount of tooth movements were determined especially after the fifth day and the following days six, seven and eight (p < 0.001). Within the limitations, according to the results of the present study, the application of ELF-EMF accelerated the orthodontic tooth movement in rats. PMID:26019497

Laser and LED external teeth-bleaching

NASA Astrophysics Data System (ADS)

Zanin, Fatima; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

2004-05-01

Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED's for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

Sox2+ progenitors in sharks link taste development with the evolution of regenerative teeth from denticles

PubMed Central

Martin, Kyle J.; Rasch, Liam J.; Cooper, Rory L.; Johanson, Zerina; Fraser, Gareth J.

2016-01-01

Teeth and denticles belong to a specialized class of mineralizing epithelial appendages called odontodes. Although homology of oral teeth in jawed vertebrates is well supported, the evolutionary origin of teeth and their relationship with other odontode types is less clear. We compared the cellular and molecular mechanisms directing development of teeth and skin denticles in sharks, where both odontode types are retained. We show that teeth and denticles are deeply homologous developmental modules with equivalent underlying odontode gene regulatory networks (GRNs). Notably, the expression of the epithelial progenitor and stem cell marker sex-determining region Y-related box 2 (sox2) was tooth-specific and this correlates with notable differences in odontode regenerative ability. Whereas shark teeth retain the ancestral gnathostome character of continuous successional regeneration, new denticles arise only asynchronously with growth or after wounding. Sox2+ putative stem cells associated with the shark dental lamina (DL) emerge from a field of epithelial progenitors shared with anteriormost taste buds, before establishing within slow-cycling cell niches at the (i) superficial taste/tooth junction (T/TJ), and (ii) deep successional lamina (SL) where tooth regeneration initiates. Furthermore, during regeneration, cells from the superficial T/TJ migrate into the SL and contribute to new teeth, demonstrating persistent contribution of taste-associated progenitors to tooth regeneration in vivo. This data suggests a trajectory for tooth evolution involving cooption of the odontode GRN from nonregenerating denticles by sox2+ progenitors native to the oral taste epithelium, facilitating the evolution of a novel regenerative module of odontodes in the mouth of early jawed vertebrates: the teeth. PMID:27930309

Type 1 diabetes mellitus effects on dental enamel formation revealed by microscopy and microanalysis.

PubMed

Silva, Bruna Larissa Lago; Medeiros, Danila Lima; Soares, Ana Prates; Line, Sérgio Roberto Peres; Pinto, Maria das Graças Farias; Soares, Telma de Jesus; do Espírito Santo, Alexandre Ribeiro

2018-03-01

Type 1 diabetes mellitus (T1DM) largely affects children, occurring therefore at the same period of deciduous and permanent teeth development. The aim of this work was to investigate birefringence and morphology of the secretory stage enamel organic extracellular matrix (EOECM), and structural and mechanical features of mature enamel from T1DM rats. Adult Wistar rats were maintained alive for a period of 56 days after the induction of experimental T1DM with a single dose of streptozotocin (60 mg/kg). After proper euthanasia of the animals, fixed upper incisors were accurately processed, and secretory stage EOECM and mature enamel were analyzed by transmitted polarizing and bright field light microscopies (TPLM and BFLM), energy-dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and microhardness testing. Bright field light microscopies and transmitted polarizing light microscopies showed slight morphological changes in the secretory stage EOECM from diabetic rats, which also did not exhibit statistically significant alterations in birefringence brightness when compared to control animals (P > .05). EDX analysis showed that T1DM induced statistically significant little increases in the amount of calcium and phosphorus in outer mature enamel (P < .01) with preservation of calcium/phosphorus ratio in that structure (P > .05). T1DM also caused important ultrastructural alterations in mature enamel as revealed by SEM and induced a statistically significant reduction of about 13.67% in its microhardness at 80 μm from dentin-enamel junction (P < .01). This study shows that T1DM may disturb enamel development, leading to alterations in mature enamel ultrastructure and in its mechanical features. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Demineralization-remineralization dynamics in teeth and bone.

PubMed

Abou Neel, Ensanya Ali; Aljabo, Anas; Strange, Adam; Ibrahim, Salwa; Coathup, Melanie; Young, Anne M; Bozec, Laurent; Mudera, Vivek

Biomineralization is a dynamic, complex, lifelong process by which living organisms control precipitations of inorganic nanocrystals within organic matrices to form unique hybrid biological tissues, for example, enamel, dentin, cementum, and bone. Understanding the process of mineral deposition is important for the development of treatments for mineralization-related diseases and also for the innovation and development of scaffolds. This review provides a thorough overview of the up-to-date information on the theories describing the possible mechanisms and the factors implicated as agonists and antagonists of mineralization. Then, the role of calcium and phosphate ions in the maintenance of teeth and bone health is described. Throughout the life, teeth and bone are at risk of demineralization, with particular emphasis on teeth, due to their anatomical arrangement and location. Teeth are exposed to food, drink, and the microbiota of the mouth; therefore, they have developed a high resistance to localized demineralization that is unmatched by bone. The mechanisms by which demineralization-remineralization process occurs in both teeth and bone and the new therapies/technologies that reverse demineralization or boost remineralization are also scrupulously discussed. Technologies discussed include composites with nano- and micron-sized inorganic minerals that can mimic mechanical properties of the tooth and bone in addition to promoting more natural repair of surrounding tissues. Turning these new technologies to products and practices would improve health care worldwide.

Demineralization–remineralization dynamics in teeth and bone

PubMed Central

Abou Neel, Ensanya Ali; Aljabo, Anas; Strange, Adam; Ibrahim, Salwa; Coathup, Melanie; Young, Anne M; Bozec, Laurent; Mudera, Vivek

2016-01-01

Biomineralization is a dynamic, complex, lifelong process by which living organisms control precipitations of inorganic nanocrystals within organic matrices to form unique hybrid biological tissues, for example, enamel, dentin, cementum, and bone. Understanding the process of mineral deposition is important for the development of treatments for mineralization-related diseases and also for the innovation and development of scaffolds. This review provides a thorough overview of the up-to-date information on the theories describing the possible mechanisms and the factors implicated as agonists and antagonists of mineralization. Then, the role of calcium and phosphate ions in the maintenance of teeth and bone health is described. Throughout the life, teeth and bone are at risk of demineralization, with particular emphasis on teeth, due to their anatomical arrangement and location. Teeth are exposed to food, drink, and the microbiota of the mouth; therefore, they have developed a high resistance to localized demineralization that is unmatched by bone. The mechanisms by which demineralization–remineralization process occurs in both teeth and bone and the new therapies/technologies that reverse demineralization or boost remineralization are also scrupulously discussed. Technologies discussed include composites with nano- and micron-sized inorganic minerals that can mimic mechanical properties of the tooth and bone in addition to promoting more natural repair of surrounding tissues. Turning these new technologies to products and practices would improve health care worldwide. PMID:27695330

[Helicobacter pylori in the development of dental caries].

PubMed

Moseeva, M V; Belova, E V; Vakhrushev, Ia M

2010-01-01

It is shown, that in patients with erosive and ulcer defects of gastroduodenal zone at settling Helicobacter pylori (Hp) in an oral cavity in 100% of cases caries develops at intensity 13.6 +/- 1.4 teeth. Produced Hp protease and ammonia cause disintegration connected to protein silica acids and reduce activity lysocim, worsening, thus, fluid and protective properties of a saliva. In the subsequent infringement of autopurification of a teeth results in accumulation of a dental strike where protease activity conditionally pathogenic microflora conducts to depolymerization and demineralization enamels of a teeth.

Reasons for extraction in primary teeth among 5-12 years school children in Haryana, India- A cross-sectional study.

PubMed

Bansal, Mohit; Gupta, Nidhi; Gupta, Preety; Arora, Vikram; Thakar, Sahil

2017-04-01

Due to high prevalence of oral diseases extraction of primary teeth is a common and a major concern in developing countries. These teeth are given least importance as they are believed to shed off automatically, thus leading to serious problems like crowding and malocclusion. A cross sectional study was carried out among children aged 5 to 12 years among 1347 children. The data was recorded on a prestructured questionnaire. Reasons for extraction of teeth were based on Kay and Blinkhorn criteria. 20.4% children were having tooth loss due to various reasons. The main reason for extraction was found to be caries in 64.3% followed by trauma in maxillary teeth among 43.02% of children. Presence of early loss of primary teeth result in occlusal disturbances and space loss among children. Hence, proper treatment regimens must be followed by the dental professionals and should be the need of the hour. Key words: Extraction, children, primary teeth, caries.

INCREASED DAMAGE TO THE TEETH BY DENTAL CARIES INDUCED BY IONIZING RADIATION (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedorov, Yu.A.

A group of rats (60 days old) given a total x-ray dose of 300 r in fractions of 100 r showed caries in 57.6% of all molars compared to an incidence of caries of 66.6% in a group of rats given a total x-ray dose of 600 r in fractions of 200 r, and an incidence of l.3% in the control group. In another series of experiments the rats were put on a special carbohydrate diet which is used to produce dental caries in experimental animals. The animals were divided into three groups. Group A was fed 0.025 g ofmore » calcium glycerophosphate per day. Group B was given water containing 1 mg/l of sodium fluoride. Group C was given no special protection against the onset of dental caries. The three groups of rats were then given a total dose of 300 r in fractions of l00 r. Group C showed dental caries in 75% of all molars, Group B was 65.2% and Group C was 34.3%. The use of calcium glycerophosphate has a protective action on the formation of dental caries. (TTT)« less

Coevolutionary patterning of teeth and taste buds

PubMed Central

Bloomquist, Ryan F.; Parnell, Nicholas F.; Phillips, Kristine A.; Fowler, Teresa E.; Yu, Tian Y.; Sharpe, Paul T.; Streelman, J. Todd

2015-01-01

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium. PMID:26483492

Coevolutionary patterning of teeth and taste buds.

PubMed

Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

2015-11-03

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

An Evo-Devo perspective on ever-growing teeth in mammals and dental stem cell maintenance

PubMed Central

Renvoisé, Elodie; Michon, Frederic

2014-01-01

A major challenge for current evolutionary and developmental biology research is to understand the evolution of morphogenesis and the mechanisms involved. Teeth are well suited for the investigation of developmental processes. In addition, since teeth are composed of hard-mineralized tissues, primarily apatite, that are readily preserved, the evolution of mammals is well documented through their teeth in the fossil record. Hypsodonty, high crowned teeth with shallow roots, and hypselodonty, ever-growing teeth, are convergent innovations that have appeared multiple times since the mammalian radiation 65 million years ago, in all tooth categories (incisors, canines, premolars, and molars). A shift to hypsodonty, or hypselodonty, during mammalian evolution is often, but not necessarily, associated with increasingly abrasive diet during important environmental change events. Although the evolution of hypsodonty and hypselodonty is considered to be the result of heterochrony of development, little has been known about the exact developmental mechanisms at the origin of these morphological traits. Developmental biologists have been intrigued by the mechanism of hypselodonty since it requires the maintenance of continuous crown formation during development via stem cell niche activity. Understanding this mechanism may allow bioengineered tooth formation in humans. Hypsodonty and hypselodonty are thus examples of phenotypic features of teeth that have both impacts in understanding the evolution of mammals and holds promise for human tooth bioengineering. PMID:25221518

Dental biothermophotonics: How photothermal methods are winning the race with X-rays for dental caries diagnostic needs of clinical dentistry

NASA Astrophysics Data System (ADS)

Mandelis, A.; Jeon, R.; Matvienko, A.; Abrams, S. H.; Amaechi, B. T.

2008-01-01

Recent trends in biothermophotonics of teeth are presented. The presentation is centered on the development of clinical-level frequency-domain photothermal radiometry and modulated luminescence to address issues associated with the early diagnosis of demineralization caries in human teeth. Biothermophotonic principles and applications to the detection of the carious state in human teeth as embodied by laser photothermal radiometry are presented and further supported by modulated luminescence. The emphasis is on recent developments with regard to abilities of these techniques to diagnose interproximal lesions between teeth, etching with phosphoric acid and with an artificial demineralization gel in order to simulate early demineralization, as well as demineralization and remineralization of dental crown enamel and root dentin. These are lesions which normally go undetected by X-ray radiographs. Comparisons with X rays, Micro-Computed Tomography (μ-CT) and Transverse Micro-Radiography (TMR) are discussed. A theoretical model involving coupled diffuse photon density and thermal-wave fields is developed and applied to frequency scans from demineralized artificial lesions to produce quantitative values for optical and thermophysical parameters of teeth as well as the thickness of the induced lesion.

Saving Single-rooted Teeth with Combined Endodontic-periodontal Lesions.

PubMed

Pico-Blanco, Alexandre; Castelo-Baz, Pablo; Caneiro-Queija, Leticia; Liñares-González, Antonio; Martin-Lancharro, Pablo; Blanco-Carrión, Juan

2016-12-01

Teeth affected by combined endodontic-periodontal lesions are usually considered by all prognosis classifications as hopeless teeth. The development of new biomaterials combined with modern endodontic and periodontal regeneration techniques may improve dental prognosis and maintain the affected teeth. Moreover, 1 of the replacement options for those teeth, dental implants, has shown an increasing number of biological and technical complications. Five patients were included in this case series study. Full periodontal and radiographic examination revealed generalized chronic periodontitis. Moreover, endodontic-periodontal lesions affecting single-rooted teeth were detected in those patients with tissue destruction beyond the apex. After splinting those teeth, conventional endodontic and nonsurgical periodontal treatment was performed. Three months later, periodontal regeneration was applied at those teeth in order to reconstruct supporting tissues and to improve dental prognosis. After a follow-up period ranging from 14 months to 17 years, it was observed that all teeth remain asymptomatic and in normal function. No signs of apical pathosis were observed, and the periodontium was stable. All patients were included in a strict maintenance program to check the periodontal and apical status. This case series shows that it is possible to change the prognosis of teeth affected by combined endodontic-periodontal lesions, even if the periodontal support is destroyed beyond the apex. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Primate dental ecology: How teeth respond to the environment.

PubMed

Cuozzo, Frank P; Ungar, Peter S; Sauther, Michelle L

2012-06-01

Teeth are central for the study of ecology, as teeth are at the direct interface between an organism and its environment. Recent years have witnessed a rapid growth in the use of teeth to understand a broad range of topics in living and fossil primate biology. This in part reflects new techniques for assessing ways in which teeth respond to, and interact with, an organism's environment. Long-term studies of wild primate populations that integrate dental analyses have also provided a new context for understanding primate interactions with their environments. These new techniques and long-term field studies have allowed the development of a new perspective-dental ecology. We define dental ecology as the broad study of how teeth respond to, or interact with, the environment. This includes identifying patterns of dental pathology and tooth use-wear, as they reflect feeding ecology, behavior, and habitat variation, including areas impacted by anthropogenic disturbance, and how dental development can reflect environmental change and/or stress. The dental ecology approach, built on collaboration between dental experts and ecologists, holds the potential to provide an important theoretical and practical framework for inferring ecology and behavior of fossil forms, for assessing environmental change in living populations, and for understanding ways in which habitat impacts primate growth and development. This symposium issue brings together experts on dental morphology, growth and development, tooth wear and health, primate ecology, and paleontology, to explore the broad application of dental ecology to questions of how living and fossil primates interact with their environments. Copyright © 2012 Wiley Periodicals, Inc.

Modelling tooth–prey interactions in sharks: the importance of dynamic testing

PubMed Central

Farina, Stacy C.; Brash, Jeffrey; Summers, Adam P.

2016-01-01

The shape of shark teeth varies among species, but traditional testing protocols have revealed no predictive relationship between shark tooth morphology and performance. We developed a dynamic testing device to quantify cutting performance of teeth. We mimicked head-shaking behaviour in feeding large sharks by attaching teeth to the blade of a reciprocating power saw fixed in a custom-built frame. We tested three tooth types at biologically relevant speeds and found differences in tooth cutting ability and wear. Teeth from the bluntnose sixgill (Hexanchus griseus) showed poor cutting ability compared with tiger (Galeocerdo cuvier), sandbar (Carcharhinus plumbeus) and silky (C. falciformis) sharks, but they also showed no wear with repeated use. Some shark teeth are very sharp at the expense of quickly dulling, while others are less sharp but dull more slowly. This demonstrates that dynamic testing is vital to understanding the performance of shark teeth. PMID:27853592

Supernumerary impacted teeth in a patient with SOX2 anophthalmia syndrome.

PubMed

Numakura, Chikahiko; Kitanaka, Sachiko; Kato, Mitsuhiro; Ishikawa, Shigeo; Hamamoto, Yoshioki; Katsushima, Yuriko; Kimura, Toshiyuki; Hayasaka, Kiyoshi

2010-09-01

SOX2 anophthalmia syndrome characteristically presents as anophthalmia or microphthalmia, with various extraocular symptoms, such as hypogonadotropic hypogonadism, brain anomaly, and esophageal abnormalities. In this report, we describe a patient with SOX2 anophthalmia syndrome complicated with a dental anomaly, multiple supernumerary impacted teeth, and persistence of deciduous teeth. Multiple supernumerary teeth are usually not solitary symptoms, but indicate systemic syndrome such as cleidocranial dysplasia. In odontogenesis, many transcriptional factors, such as BMPs, FGFs, and Wnts, play significant roles and SOX2 is known to interact with some of them. The role of SOX2 in dental development remains unknown, however, multiple supernumerary teeth can be considered as extraocular symptoms of SOX2 anophthalmia syndrome, rather than the coincidence of two rare diseases.

Shaping of Rack Cutter Original Profile for Fine-module Ratchet Teeth Cutting

NASA Astrophysics Data System (ADS)

Sharkov, O. V.; Koryagin, S. I.; Velikanov, N. L.

2018-05-01

The design models and the process of shaping the cutting edges of the rack cutter for cutting fine-module ratchet teeth are considered in the article. The use of fine-module ratchet teeth can reduce the noise and impact loads during operation of the freewheel mechanisms. Mathematical dependencies for calculating the coordinates determining the geometric position of the points of the front and back edges of the cutting profile of the rack cutter, the workpiece angle of rotation during cutting the ratchet teeth were obtained. When applying the developed method, the initial data are: the radii of the workpiece circumferences passing through the dedendum of the external and internal cut teeth; gradient angles of the front and back edges of the rail.

Laser and LED external teeth-bleaching

NASA Astrophysics Data System (ADS)

Zanin, Fatima A.; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

2004-09-01

Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode Laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED"s for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

Children and Facial Trauma

MedlinePlus

... Injuries to the teeth and surrounding dental structures style Isolated injuries to teeth are quite common and ... Head and Neck Get Involved Professional Development Practice Management ENT Careers Marketplace Privacy Policy Terms of Use © ...

Three-dimensional reconstruction of teeth and jaws based on segmentation of CT images using watershed transformation.

PubMed

Naumovich, S S; Naumovich, S A; Goncharenko, V G

2015-01-01

The objective of the present study was the development and clinical testing of a three-dimensional (3D) reconstruction method of teeth and a bone tissue of the jaw on the basis of CT images of the maxillofacial region. 3D reconstruction was performed using the specially designed original software based on watershed transformation. Computed tomograms in digital imaging and communications in medicine format obtained on multispiral CT and CBCT scanners were used for creation of 3D models of teeth and the jaws. The processing algorithm is realized in the stepwise threshold image segmentation with the placement of markers in the mode of a multiplanar projection in areas relating to the teeth and a bone tissue. The developed software initially creates coarse 3D models of the entire dentition and the jaw. Then, certain procedures specify the model of the jaw and cut the dentition into separate teeth. The proper selection of the segmentation threshold is very important for CBCT images having a low contrast and high noise level. The developed semi-automatic algorithm of multispiral and cone beam computed tomogram processing allows 3D models of teeth to be created separating them from a bone tissue of the jaws. The software is easy to install in a dentist's workplace, has an intuitive interface and takes little time in processing. The obtained 3D models can be used for solving a wide range of scientific and clinical tasks.

Regenerative endodontics: A way forward.

PubMed

Diogenes, Anibal; Ruparel, Nikita B; Shiloah, Yoav; Hargreaves, Kenneth M

2016-05-01

Immature teeth are susceptible to infections due to trauma, anatomic anomalies, and caries. Traditional endodontic therapies for immature teeth, such as apexification procedures, promote resolution of the disease and prevent future infections. However, these procedures fail to promote continued root development, leaving teeth susceptible to fractures. Regenerative endodontic procedures (REPs) have evolved in the past decade, being incorporated into endodontic practice and becoming a viable treatment alternative for immature teeth. The authors have summarized the status of regenerative endodontics on the basis of the available published studies and provide insight into the different levels of clinical outcomes expected from these procedures. Substantial advances in regenerative endodontics are allowing a better understanding of a multitude of factors that govern stem cell-mediated regeneration and repair of the damaged pulp-dentin complex. REPs promote healing of apical periodontitis, continued radiographic root development, and, in certain cases, vitality responses. Despite the clinical success of these procedures, they appear to promote a guided endodontic repair process rather than a true regeneration of physiological-like tissue. Immature teeth with pulpal necrosis with otherwise poor prognosis can be treated with REPs. These procedures do not preclude the possibility of apexification procedures if attempts are unsuccessful. Therefore, REPs may be considered first treatment options for immature teeth with pulpal necrosis. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

Real-time detection of dental calculus by blue-LED-induced fluorescence spectroscopy.

PubMed

Qin, Y L; Luan, X L; Bi, L J; Lü, Z; Sheng, Y Q; Somesfalean, G; Zhou, C N; Zhang, Z G

2007-05-25

Successful periodontal therapy requires sensitive techniques to discriminate dental calculus from healthy teeth. The aim of the present study was to develop a fluorescence-based procedure to enable real-time detection and quantification of dental calculus. Thirty human teeth--15 teeth with sub- and supragingival calculus and 15 healthy teeth--covered with a layer of physiological saline solution or blood were illuminated by a focused blue LED light source of 405 nm. Autofluorescence spectra recorded along a randomly selected line stretching over the crown-neck-root area of each tooth were utilized to evaluate a so called calculus parameter R, which was selected to define a relationship between the integrated intensities specific for healthy teeth and for calculus in the 477-497 nm (S(A)) and 628-685 nm (S(B)) wavelength regions, respectively. Statistical analysis was performed and a cut-off threshold of R=0.2 was found to distinguish dental calculus from healthy teeth with 100% sensitivity and specificity under various experimental conditions. The results of the spectral evaluation were confirmed by clinical and histological findings. Automated real-time detection and diagnostics for clinical use were implemented by a corresponding software program written in Visual Basic language. The method enables cost-effective and reliable calculus detection, and can be further developed for imaging applications.

Reasons for extraction in primary teeth among 5-12 years school children in Haryana, India- A cross-sectional study

PubMed Central

Gupta, Nidhi; Gupta, Preety; Arora, Vikram; Thakar, Sahil

2017-01-01

Background Due to high prevalence of oral diseases extraction of primary teeth is a common and a major concern in developing countries. These teeth are given least importance as they are believed to shed off automatically, thus leading to serious problems like crowding and malocclusion. Material and Methods A cross sectional study was carried out among children aged 5 to 12 years among 1347 children. The data was recorded on a prestructured questionnaire. Reasons for extraction of teeth were based on Kay and Blinkhorn criteria. Results 20.4% children were having tooth loss due to various reasons. The main reason for extraction was found to be caries in 64.3% followed by trauma in maxillary teeth among 43.02% of children. Conclusions Presence of early loss of primary teeth result in occlusal disturbances and space loss among children. Hence, proper treatment regimens must be followed by the dental professionals and should be the need of the hour. Key words:Extraction, children, primary teeth, caries. PMID:28469820

Citric acid compounds of tangerines peel extract (Citrus reticulata) as potential materials teeth whitening

NASA Astrophysics Data System (ADS)

Pratiwi, F.; Tinata, J. K.; Prakasa, A. W.; Istiqomah; Hartini, E.; Isworo, S.

2017-04-01

Peel of citrus fruit (Citrus reticulata) has a variety of possible chemical compounds that may serve as a potential whitening teeth. This research is conducted on a laboratory scale; therefore, it needs to be developed on an application scale. A quasi-experimental was employed in this study. Citric acid extraction was carried out on the type of Sweet Orange (Citrus Aurantium L), Tangerine (Citrus Reticulata Blanco or Citrus Nobilis), Pomelo (Citrus Maxima Merr, Citrus grandis Osbeck), and Lemon (Citrus Limon Linn). Citric acid’s ability test as teeth whitener was performed on premolar teeth with concentrations of 2.5%, 5%, and 10%. The experiments were replicated in 3 times, and teeth whiteness level was measured using Shade Guide VITA Classical. The result of this research showed that citric acid in every kind of orange peel with various concentration has different abilities on whitening teeth. The highest colour level obtained from Tangerine peel’s citric acid concentration of 5%. Orange peel extract has the best teeth whitening abilities tested by the method of Gass Chromatography to know the active ingredients.

Infant teething information on the world wide web: taking a byte out of the search.

PubMed

Kozuch, Mary; Peacock, Erica; D'Auria, Jennifer P

2015-01-01

The purpose of this study was to describe and evaluate the quality of infant teething information on selected popular parenting Web sites. Two checklists were used to evaluate the quality of the 16 parenting sites and infant teething-specific content included on each site. Three of the 16 parenting sites did not contain teething-specific articles. Teething-specific content found on 13 of the 16 sites supported a connection between the process of teething and nonspecific symptoms with a perception that management is required. Popular management strategies included chewing on chilled objects, gingival massage, and the use of over-the-counter medications. Information about possible adverse effects of administering medications for infant teething was not found on the majority of sites. Eleven of the 16 sites advised parents to contact their primary care provider if they were uncertain about management for infant teething or whether the symptoms were related to illness. Although infant teething has an evidence base from which parents and professionals can make safe decisions about symptoms and treatment, translating the evidence into professional practice and health-related information on the Internet remains a challenge. Parents and pediatric health providers would benefit greatly from the development of clinical practice guidelines summarizing our present-day understanding of teething symptoms and the limited evidence supporting the use of over-the-counter medications. Copyright © 2015 National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved.

Tooth enamel mineralization in ungulates: implications for recovering a primary isotopic time-series

NASA Astrophysics Data System (ADS)

Passey, Benjamin H.; Cerling, Thure E.

2002-09-01

Temporal changes in the carbon and oxygen isotopic composition of an animal are an environmental and behavioral input signal that is recorded into the enamel of developing teeth. In this paper, we evaluate changes in phosphorus content and density along the axial lengths of three developing ungulate teeth to illustrate the protracted nature of mineral accumulation in a volume of developing enamel. The least mature enamel in these teeth contains by volume about 25% of the mineral mass of mature enamel, and the remaining 75% of the mineral accumulates during maturation. Using data from one of these teeth (a Hippopotamus amphibius canine), we develop a model for teeth growing at constant rate that describes how an input signal is recorded into tooth enamel. The model accounts for both the temporal and spatial patterns of amelogenesis (enamel formation) and the sampling geometry. The model shows that input signal attenuation occurs as a result of time-averaging during amelogenesis when the maturation interval is long compared to the duration of features in the input signal. Sampling does not induce significant attenuation, provided that the sampling interval is several times shorter than the maturation interval. We present a detailed δ 13C and δ 18O record for the H. amphibius canine and suggest possible input isotope signals that may have given rise to the measured isotope signal.

Amelogenesis imperfecta

MedlinePlus

... a tooth development disorder. It causes the tooth enamel to be thin and abnormally formed. Enamel is the outer layer of teeth. ... The enamel of the tooth is soft and thin. The teeth appear yellow and are easily damaged. Both baby ...

14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. DETAILS OF GATE OPERATING MECHANISM, SHOWING RACK SECTION, CUT TEETH, CAST TEETH, GATE PINION (1907) - Nine Mile Hydroelectric Development, Powerhouse, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

Synergistic acceleration of experimental tooth movement by supplementary high-frequency vibration applied with a static force in rats.

PubMed

Takano-Yamamoto, Teruko; Sasaki, Kiyo; Fatemeh, Goudarzi; Fukunaga, Tomohiro; Seiryu, Masahiro; Daimaruya, Takayoshi; Takeshita, Nobuo; Kamioka, Hiroshi; Adachi, Taiji; Ida, Hiroto; Mayama, Atsushi

2017-10-25

Several recent prospective clinical trials have investigated the effect of supplementary vibration applied with fixed appliances in an attempt to accelerate tooth movement and shorten the duration of orthodontic treatment. Among them, some studies reported an increase in the rate of tooth movement, but others did not. This technique is still controversial, and the underlying cellular and molecular mechanisms remain unclear. In the present study, we developed a new vibration device for a tooth movement model in rats, and investigated the efficacy and safety of the device when used with fixed appliances. The most effective level of supplementary vibration to accelerate tooth movement stimulated by a continuous static force was 3 gf at 70 Hz for 3 minutes once a week. Furthermore, at this optimum-magnitude, high-frequency vibration could synergistically enhance osteoclastogenesis and osteoclast function via NF-κB activation, leading to alveolar bone resorption and finally, accelerated tooth movement, but only when a static force was continuously applied to the teeth. These findings contribute to a better understanding of the mechanism by which optimum-magnitude high-frequency vibration accelerates tooth movement, and may lead to novel approaches for the safe and effective treatment of malocclusion.

The decade of overdentures: 1970-1980.

PubMed

Fenton, A H

1998-01-01

Jaw bones resorb when teeth are lost. People cannot function as well with complete dentures compared with their natural teeth. As more people are living longer and these cumulative effects become increasingly documented, dentists in the 1970s attached more importance to keeping teeth. The concept of overdentures developed as a simple and economic alternative to prolong the retention and function of the last few teeth in a compromised dentition. The previous option was extensive fixed prosthodontics. An overdenture is a complete or removable partial denture that has one or more tooth roots to provide support. Rather than extracting all compromised teeth, the crowns, and pulpal tissue of selected teeth (usually two anterior teeth) are removed. The remaining root projecting through the mucosa is restored and/or contoured. With the crown removed, there is space to cover the area with a denture. The root has less mobility, and its retention retards bone resorption. Overdentures with roots are more stable, and patients can chew better than with dentures supported on residual alveolar bone and mucosal tissue alone. Keeping even a few teeth has a strong psychological value for some patients. Patients who have lost teeth, adjacent tissue, and bone need replacement of more oral structures than tooth crowns alone can provide. A complete denture with flange contours can restore tissue and appearance. The conventional tooth-supported overdenture concept continues to be an accepted treatment modality and has now been adapted to implants.

The genetic basis of modularity in the development and evolution of the vertebrate dentition.

PubMed Central

Stock, D W

2001-01-01

The construction of organisms from units that develop under semi-autonomous genetic control (modules) has been proposed to be an important component of their ability to undergo adaptive phenotypic evolution. The organization of the vertebrate dentition as a system of repeated parts provides an opportunity to study the extent to which phenotypic modules, identified by their evolutionary independence from other such units, are related to modularity in the genetic control of development. The evolutionary history of vertebrates provides numerous examples of both correlated and independent evolution of groups of teeth. The dentition itself appears to be a module of the dermal exoskeleton, from which it has long been under independent genetic control. Region-specific tooth loss has been a common trend in vertebrate evolution. Novel deployment of teeth and reacquisition of lost teeth have also occurred, although less frequently. Tooth shape differences within the dentition may be discontinuous (referred to as heterodonty) or graded. The occurrence of homeotic changes in tooth shape provides evidence for the decoupling of tooth shape and location in the course of evolution. Potential mechanisms for region-specific evolutionary tooth loss are suggested by a number of mouse gene knockouts and human genetic dental anomalies, as well as a comparison between fully-developed and rudimentary teeth in the dentition of rodents. These mechanisms include loss of a tooth-type-specific initiation signal, alterations of the relative strength of inductive and inhibitory signals acting at the time of tooth initiation and the overall reduction in levels of proteins required for the development of all teeth. Ectopic expression of tooth initiation signals provides a potential mechanism for the novel deployment or reacquisition of teeth; a single instance is known of a gene whose ectopic expression in transgenic mice can lead to ectopic teeth. Differences in shape between incisor and molar teeth in the mouse have been proposed to be controlled by the region-specific expression of signalling molecules in the oral epithelium. These molecules induce the expression of transcription factors in the underlying jaw mesenchyme that may act as selectors of tooth type. It is speculated that shifts in the expression domains of the epithelial signalling molecules might be responsible for homeotic changes in tooth shape. The observation that these molecules are regionally restricted in the chicken, whose ancestors were not heterodont, suggests that mammalian heterodonty may have evolved through the use of patterning mechanisms already acting on skeletal elements of the jaws. In general, genetic and morphological approaches identify similar types of modules in the dentition, but the data are not yet sufficient to identify exact correspondences. It is speculated that modularity may be achieved by gene expression differences between teeth or by differences in the time of their development, causing mutations to have cumulative effects on later-developing teeth. The mammalian dentition, for which virtually all of the available developmental genetic data have been collected, represents a small subset of the dental diversity present in vertebrates as a whole. In particular, teleost fishes may have a much more extensive dentition. Extension of research on the genetic control of tooth development to this and other vertebrate groups has great potential to further the understanding of modularity in the dentition. PMID:11604128

Assessment of dental caries prevention program applied to a cohort of elementary school children of Kebemer, a city in Senegal.

PubMed

Daouda, Faye; Aïda, Kanouté; Mbacké, Lo Cheikh; Mamadou, Mbaye

2016-08-01

Dental caries is frequently observed in children, particularly among those residing in developing countries. The most adapted strategies against this pathology remains prevention based on information, education, and communication (IEC), as well as on early diagnosis and treatment. We carried out a study that aimed to analyze the development of dental caries in a cohort of school children followed during their primary education. The objective was to assess the evolution of the dental status of a cohort of students during their elementary curriculum. A cohort of school children was followed during 6 years from the first grade to the sixth grade. Monitoring of these school children focused every year on IEC based on learning methods of brushing messages, dietary advice, systematic visits, fluoride use, and primary dental care. During the school year, the students were periodically subjected to education and communication briefings (IEC). Primary care consisted of extracting and descaling rhizalyzed teeth in the same period. The data from this review were collected using the World Health Organization questionnaire, and statistical analysis was performed with the software Epi-info version 6.04 d. The mean age of the 171 school children was 6 years in the first grade and 11 years in the sixth grade. In the first grade, the decayed permanent teeth prevalence was 31.6% and the In permanent teeth: Decayed, missing or filled teeth (DMF/T) was 0.47. The decayed primary teeth prevalence was 75% and the in primary teeth: decayed or filled teeth (df/t) 2.23. In the sixth year, the prevalence of decayed permanent teeth was 51% and DMF/T 0.36 whereas the decayed primary teeth prevalence was 12% and the df/t was 0.19. The prevalence of decayed permanent teeth increased from 31.6 to 51% whereas the mean DMF/T was not statistically different between school children of the first and sixth grade class. The promotion of oral health by IEC messages and monitoring of children constitute an effective preventive method for children's oral care.

Evaluation of age-related changes with cross-sectional CT imaging of teeth

NASA Astrophysics Data System (ADS)

Fukui, Tatsumasa; Kita, Kanade; Kamemoto, Hiromasa; Nishiyama, Wataru; Yoshida, Hiroyasu; Iida, Yukihiro; Katsumata, Akitoshi; Muramatsu, Chisako; Fujita, Hiroshi

2017-03-01

Tooth pulp atrophy occurs with increasing age. An age estimation procedure using dental cone beam computed tomography (CBCT) imaging was developed. Clinical dental CBCT images of 60 patients (aged from 20 to 80 years) were evaluated. The ratio of the cross-sectional area of the pulp cavity to the cross-sectional area of the tooth (pulp cavity ratio) was calculated. The pulp cavity ratio in the labio-lingual plane of the mandibular anterior teeth and the mesio-distal plane of the maxillary anterior teeth was strongly correlated with the patients' age. The pulp cavity ratio of anterior teeth may be a useful parameter for estimating age.

The relationship between oral health status and biological and psychosocial function in the bedridden elderly.

PubMed

Hanada, N; Tada, A

2001-01-01

The present study was conducted in order to determine what item of biological and psychosocial function is related to oral health status in the bedridden elderly. The subjects were 94 elderly individuals (30 males, 64 females) who had been admitted to a nursing home in Chiba city, Japan. We assessed the number of remaining teeth and the number of functional teeth as oral health status variables. Biological and psychosocial function levels were determined using the functional independence measure method developed by the State University of New York at Buffalo. More than 70% of subjects had less than ten remaining teeth. Almost all subjects needed prosthesis treatment. More than 50% of subjects had 27 or less functional teeth. Mann-Whitney U-test and logistic regression models showed that 'expression' was concerned with the number of remaining teeth and 'bladder management', 'locomotion', 'transfers' were related to the number of functional teeth. These data suggest close relation between oral health status and biological and psychosocial function levels in the bedridden elderly.

[Effect of oral intervention on matrix metalloproteinase-2, 9 expression in carotid arteries and serum interleukin-6 in rats with chronic periodontitis].

PubMed

Li, Jieting; Liu, Yujiao; Ren, Xiuyun; Chang, Le; Yue, Zijie; Shi, Xuexue

2014-09-01

To establish chronic periodontitis model in SD rats, and to investigate the effect of oral intervention on atherosclerosis. Fifty male SD rats were randomly divided into three groups, group A (normal control), group B (atherosclerosis,As) and group C (chronic periodontitis, CP). Group C was further divided into group C1 (natural process), group C2 (simple mechanical treatment), group C3 (systemic antibiotics), group C4-1 (teeth extraction) and group C4-2 (teeth extraction+systemic antibiotics), each group consisted of 7 rats. Every group received oral intervention. Serum interleukin (IL)- 6 levels were detected in five different time points (1, 3, 5, 7, 9 weeks after a successful modeling) by enzyme linked immunosorbent assay. All animals were killed after 24 weeks. Matrix metalloproteinase (MMP)- 2, 9 in the proximal aorta was detected by immuno histochemistry. The levels of serum IL-6 in groups B and C1 increased gradually with time and became significantly higher than that in group A (P < 0.01). Levels of serum IL-6 were increased gradually in each intervention group (C2, C3, C4-1, C4-2) and reached its peak at 5 weeks after modeling [C2:(62.3 ± 14.3) ng/L, C3:(58.2 ± 8.7) ng/L, C4-1:(127.0 ± 29.9) ng/L, C4-2:(120.6 ± 23.1) ng/L]. Compared with group B, group C4- 1 and C4- 2 increased most significantly (P < 0.01). Levels of serum IL- 6 decreased gradually. Eventually, group C2 [(28.6 ± 8.1) ng/L], C3 [(40.8 ± 15.1) ng/L] and C4-2 [(32.7 ± 11.1) ng/L] were significantly lower than group B (P < 0.05), and in group C2 IL- 6 was the lowest. Although levels of serum of IL-6 significantly decreased in group C4-1 [(72.8 ± 16.4) ng/L], but remained the highest. Immunohistochemistry showed that MMP-2, 9 were expressed in group B, C1 and C4-1, and significantly higher than in group A (183.0 ± 2.0, 181.3 ± 2.0), the gray value differences were statistically significant (P < 0.01). Group C4-1 (123.1 ± 2.9, 121.0 ± 3.2) was the strongest, group B (126.4 ± 2.0, 124.8 ± 2.8) and C1 (140.0 ± 2.2, 139.7 ± 3.2) were decreased (P < 0.01). While group C2(169.3 ± 3.4, 169.7 ± 2.3), C3 (149.0 ± 1.7, 145.1 ± 2.5) and C4-2 (157.7 ± 1.2, 155.8 ± 2.7) were significantly lower than group C1 (P < 0.01), and group C2 was close to normal. Periodontitis could increase the risk of atherosclerosis in rats with chronic periodontitis. Periodontal mechanical treatment and teeth extraction may increase the risk of As in the short time. However, the risk would gradually reduce in a long time.

New models for age estimation and assessment of their accuracy using developing mandibular third molar teeth in a Thai population.

PubMed

Duangto, P; Iamaroon, A; Prasitwattanaseree, S; Mahakkanukrauh, P; Janhom, A

2017-03-01

Age estimation using developing third molar teeth is considered an important and accurate technique for both clinical and forensic practices. The aims of this study were to establish population-specific reference data, to develop age prediction models using mandibular third molar development, to test the accuracy of the resulting models, and to find the probability of persons being at the age thresholds of legal relevance in a Thai population. A total of 1867 digital panoramic radiographs of Thai individuals aged between 8 and 23 years was selected to assess dental age. The mandibular third molar development was divided into nine stages. The stages were evaluated and each stage was transformed into a development score. Quadratic regression was employed to develop age prediction models. Our results show that males reached mandibular third molar root formation stages earlier than females. The models revealed a high correlation coefficient for both left and right mandibular third molar teeth in both sexes (R = 0.945 and 0.944 in males, R = 0.922 and 0.923 in females, respectively). Furthermore, the accuracy of the resulting models was tested in randomly selected 374 cases and showed low error values between the predicted dental age and the chronological age for both left and right mandibular third molar teeth in both sexes (-0.13 and -0.17 years in males, 0.01 and 0.03 years in females, respectively). In Thai samples, when the mandibular third molar teeth reached stage H, the probability of the person being over 18 years was 100 % in both sexes.

Use of new targeted cancer therapies in children: effects on dental development and risk of jaw osteonecrosis: a review.

PubMed

Hernandez, Magali; Phulpin, Bérengère; Mansuy, Ludovic; Droz, Dominique

2017-05-01

New targeted cancer therapies such as bisphosphonates, denosumab, and bevacizumab are routinely used in adult for the past decades. Their introduction into pediatric medicine is more recent that means there is a paucity of data on long-term effects on dental development and on the risk of osteonecrosis of jaw. This study aimed to outline adverse effects of new targeted cancer therapies on oral cavity including dental abnormalities observed in pediatric population treated with these molecules and the risk of osteonecrosis of the jaw (ONJ). The impact of bisphosphonates and denosumab on bone remodeling (inhibition of osteoclasts) could interfere with teeth exfoliation and eruption processes, causing a tooth eruption delay. This hypothesis was confirmed, bisphosphonate-treated rats presented tooth eruption delay, and bisphosphonate therapy was associated with a mean delay of 1.67 years in tooth eruption in children with osteogenesis imperfecta. Another study showed that the inhibition of RANK/RANKL by denosumab was associated with a lack of tooth eruption in animals. Several animal studies reported that bisphosphonate could also induce dental abnormalities including defective amelogenesis and dentinogenesis in rats, but there is no evidence of such effects in children; only one case of enamel hypoplasia in a child treated for idiopathic arterial calcification with bisphosphate was reported. To date, there has been no reported case of ONJ in children treated with bisphosphonates, denosumab, or bevacizumab. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lamniform Shark Teeth from the Late Cretaceous of Southernmost South America (Santa Cruz Province, Argentina)

PubMed Central

Schroeter, Elena R.; Egerton, Victoria M.; Ibiricu, Lucio M.; Lacovara, Kenneth J.

2014-01-01

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage. PMID:25141301

Lamniform shark teeth from the late cretaceous of southernmost South America (Santa Cruz province, Argentina).

PubMed

Schroeter, Elena R; Egerton, Victoria M; Ibiricu, Lucio M; Lacovara, Kenneth J

2014-01-01

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage.

Multipotent cells from the human third molar: feasibility of cell-based therapy for liver disease.

PubMed

Ikeda, Etsuko; Yagi, Kiyohito; Kojima, Midori; Yagyuu, Takahiro; Ohshima, Akira; Sobajima, Satoshi; Tadokoro, Mika; Katsube, Yoshihiro; Isoda, Katsuhiro; Kondoh, Masuo; Kawase, Masaya; Go, Masahiro J; Adachi, Hisashi; Yokota, Yukiharu; Kirita, Tadaaki; Ohgushi, Hajime

2008-05-01

Adult stem cells have been reported to exist in various tissues. The isolation of high-quality human stem cells that can be used for regeneration of fatal deseases from accessible resources is an important advance in stem cell research. In the present study, we identified a novel stem cell, which we named tooth germ progenitor cells (TGPCs), from discarded third molar, commonly called as wisdom teeth. We demonstrated the characterization and distinctiveness of the TGPCs, and found that TGPCs showed high proliferation activity and capability to differentiate in vitro into cells of three germ layers including osteoblasts, neural cells, and hepatocytes. TGPCs were examined by the transplantation into a carbon tetrachloride (CCl4)-treated liver injured rat to determine whether this novel cell source might be useful for cell-based therapy to treat liver diseases. The successful engraftment of the TGPCs was demonstrated by PKH26 fluorescence in the recipient's rat as to liver at 4 weeks after transplantation. The TGPCs prevented the progression of liver fibrosis in the liver of CCl4-treated rats and contributed to the restoration of liver function, as assessed by the measurement of hepatic serum markers aspartate aminotransferase and alanine aminotransferase. Furthermore, the liver functions, observed by the levels of serum bilirubin and albumin, appeared to be improved following transplantation of TGPCs. These findings suggest that multipotent TGPCs are one of the candidates for cell-based therapy to treat liver diseases and offer unprecedented opportunities for developing therapies in treating tissue repair and regeneration.

Alternatives to silver amalgam and resin composite in pediatric dentistry.

PubMed

Croll, T P

1998-11-01

Silver amalgam has become a less attractive dental restorative material for restoration of primary teeth. After many decades of scientific and nonscientific controversy, use of silver amalgam for primary teeth is waning, not because of its mercury content but because dentistry has come up with more suitable materials. This article reviews the development and use of glass-ionomer silver-cermet cements, resin-modified glass-ionomer cements, and polyacid-modified resin composites (compomers) for restoration of primary teeth.

Locally limited inhibition of bone resorption and orthodontic relapse by recombinant osteoprotegerin protein.

PubMed

Schneider, D A; Smith, S M; Campbell, C; Hayami, T; Kapila, S; Hatch, N E

2015-04-01

To determine minimal dose levels required for local inhibition of orthodontic relapse by recombinant OPG protein (OPG-Fc), while also determining effects of injected OPG-Fc on alveolar bone and long bone. The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Eighteen male Sprague Dawley rats. Maxillary molars were moved with nickel-titanium springs and then allowed to relapse in Sprague Dawley rats. Upon appliance removal, animals were injected with a single dose of 1.0 mg/kg OPG-Fc, 0.1 mg/kg OPG-Fc, or phosphate-buffered saline (vehicle) just distal to the molar teeth. Tooth movement measurements were made from stone casts, which were scanned and digitally measured. Alveolar tissues were examined by histology. Micro-computed tomography was used to quantify changes in alveolar and femur bone. Local injection of OPG-Fc inhibited molar but not incisor relapse, when compared to vehicle-injected animals. No significant differences in alveolar or femur bone were seen between the three treatment groups after 24 days of relapse. Our results demonstrate that a single local injection of OPG-Fc effectively inhibits orthodontic relapse, with minimal systemic bone metabolic effects. Our results also show that a single injection of OPG-Fc will influence tooth movement only in teeth close to the injection site. These findings indicate that OPG-Fc has potential as a safe and effective pharmacological means to locally control osteoclasts, for uses such as maintaining anchorage during orthodontic tooth movement and preventing orthodontic relapse in humans. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tooth development and histology patterns in lamniform sharks (Elasmobranchii, Lamniformes) revisited.

PubMed

Schnetz, Lisa; Pfaff, Cathrin; Kriwet, Jürgen

2016-12-01

The dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. Also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. High-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order Lamniformes, which were considered not to be phylogenetically informative, the histotype and the number of teeth per tooth file. Additionally, the development and mineralization patterns of the teeth of the two osteodont lamniforms Lamna nasus and Alopias superciliosus were compared. We discuss the importance of these dental characters for phylogenetic interpretations to assess the quality of these characters in resolving lamniform relationships. The dental characters suggest that (1) Lamniformes are the only modern-level sharks exhibiting the osteodont histotype, (2) the osteodont histotype in lamniform sharks is a derived state in modern-level sharks (Elasmobranchii), (3) the osteodont type, conversely is convergently achieved when the clade Chondrichthyes is considered and thus might comprise a functional rather than a phylogenetic signal, and (4) there is an increase in the number of teeth per file throughout lamniform phylogeny. Structural development of the teeth of L. nasus and A. superciliosus is congruent with a previous investigation of the lamniform shark Carcharodon carcharias. J. Morphol. 277:1584-1598, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Comparative evaluation of platelet-rich fibrin and mineral trioxide aggregate as pulpotomy agents in permanent teeth with incomplete root development: a randomized controlled trial.

PubMed

Keswani, Deepa; Pandey, Ramesh K; Ansari, Afroz; Gupta, Shalini

2014-05-01

The purpose of this study was to evaluate and compare, clinically and radiographically, the effects of platelet-rich fibrin (PRF) and mineral trioxide aggregate (MTA) as pulpotomy agents in permanent teeth with incomplete root development. A total number of 70 children requiring pulpotomy in 70 permanent molars with incomplete root development were screened. Sixty-two patients met the inclusion criteria and were enrolled in the study. The patients were randomly allocated equally in 2 treatment groups. MTA pulpotomy was performed in group A (the control group), and PRF pulpotomy was performed in group B (the experimental group). The treated teeth were restored with amalgam followed by stainless steel crowns. Clinical and radiographic evaluations were performed after 6, 12, and 24 months. Thus, the data obtained were blindly analyzed using the chi-square test. There was no significant difference between the 2 groups in terms of clinical and radiologic success. Radiographically, all available cases (53 teeth) showed evidence of root growth and canal narrowing. Complete apical closure was observed in 88.8% in the PRF group (experimental group) and 80.07% of roots in the MTA group (control group), respectively, at 24 months. PRF could be used as a suitable biological and economic alternative to MTA in pulpotomy procedures of permanent teeth with incomplete root development. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Early development and replacement of the stickleback dentition

PubMed Central

Ellis, Nicholas A.; Donde, Nikunj N.; Miller, Craig T.

2017-01-01

Teeth have long served as a model system to study basic questions about vertebrate organogenesis, morphogenesis, and evolution. In non-mammalian vertebrates, teeth typically regenerate throughout adult life. Fish have evolved a tremendous diversity in dental patterning in both their oral and pharyngeal dentitions, offering numerous opportunities to study how morphology develops, regenerates, and evolves in different lineages. Threespine stickleback fish (Gasterosteus aculeatus) have emerged as a new system to study how morphology evolves, and provide a particularly powerful system to study the development and evolution of dental morphology. Here we describe the oral and pharyngeal dentitions of stickleback fish, providing additional morphological, histological, and molecular evidence for homology of oral and pharyngeal teeth. Focusing on the ventral pharyngeal dentition in a dense developmental time course of lab-reared fish, we describe the temporal and spatial consensus sequence of early tooth formation. Early in development, this sequence is highly stereotypical and consists of seventeen primary teeth forming the early tooth field, followed by the first tooth replacement event. Comparing this detailed morphological and ontogenetic sequence to that described in other fish reveals that major changes to how dental morphology arises and regenerates have evolved across different fish lineages. PMID:27145214

Zebrafish sp7 mutants show tooth cycling independent of attachment, eruption and poor differentiation of teeth.

PubMed

Kague, E; Witten, P E; Soenens, M; Campos, C L; Lubiana, T; Fisher, S; Hammond, C; Brown, K Robson; Passos-Bueno, M R; Huysseune, A

2018-03-15

The capacity to fully replace teeth continuously makes zebrafish an attractive model to explore regeneration and tooth development. The requirement of attachment bone for the appearance of replacement teeth has been hypothesized but not yet investigated. The transcription factor sp7 (osterix) is known in mammals to play an important role during odontoblast differentiation and root formation. Here we study tooth replacement in the absence of attachment bone using sp7 zebrafish mutants. We analysed the pattern of tooth replacement at different stages of development and demonstrated that in zebrafish lacking sp7, attachment bone is never present, independent of the stage of tooth development or fish age, yet replacement is not interrupted. Without bone of attachment we observed abnormal orientation of teeth, and abnormal connection of pulp cavities of predecessor and replacement teeth. Mutants lacking sp7 show arrested dentinogenesis, with non-polarization of odontoblasts and only a thin layer of dentin deposited. Osteoclast activity was observed in sp7 mutants; due to the lack of bone of attachment, remodelling was diminished but nevertheless present along the pharyngeal bone. We conclude that tooth replacement is ongoing in the sp7 mutant despite poor differentiation and defective attachment. Without bone of attachment tooth orientation and pulp organization are compromised. Copyright © 2018 Elsevier Inc. All rights reserved.

A Review on Vital Pulp Therapy in Primary Teeth

PubMed Central

Parisay, Iman; Ghoddusi, Jamileh; Forghani, Maryam

2015-01-01

Maintaining deciduous teeth in function until their natural exfoliation is absolutely necessary. Vital pulp therapy (VPT) is a way of saving deciduous teeth. The most important factors in success of VPT are the early diagnosis of pulp and periradicular status, preservation of the pulp vitality and proper vascularization of the pulp. Development of new biomaterials with suitable biocompatibility and seal has changed the attitudes towards preserving the reversible pulp in cariously exposed teeth. Before exposure and irreversible involvement of the pulp, indirect pulp capping (IPC) is the treatment of choice, but after the spread of inflammation within the pulp chamber and establishment of irreversible pulpitis, removal of inflamed pulp tissue is recommended. In this review, new concepts in preservation of the healthy pulp tissue in deciduous teeth and induction of the reparative dentin formation with new biomaterials instead of devitalization and the consequent destruction of vital tissues are discussed. PMID:25598803

Functional and esthetic rehabilitation of a child with amelogenesis imperfecta: a case report.

PubMed

Moura, Carmem Dolores Vilarinho Soares de; Pontes, Alessandra Silva; Lopes, Teresinha Soares Pereira; Moura, Lúcia Fátima Almeida de Deus; Lima, Marina Deus Moura de

2017-01-01

Amelogenesis imperfecta (AI) is a tooth disorder characterized by the abnormal development of the enamel in response to mutations in the genes involved in amelogenesis. The objective of this article is to present the clinical case of a child with AI in the primary dentition phase. A 4-year-old boy was presented to a clinic by his mother, who complained that her son's smile esthetics were compromised by "weak and yellow teeth." All the teeth showed yellowish discoloration as well as crumbling or missing enamel. Due to the absence of carious lesions and the presence of normal pulp in the teeth, it was decided to restore the dentition with indirect crowns of ceramic-optimized polymer, also known as ceromer. No preparations were performed on the teeth. For this patient, indirect ceromer restorations presented a good treatment option for the rehabilitation of primary teeth affected by AI.

An animal model to study regenerative endodontics.

PubMed

Torabinejad, Mahmoud; Corr, Robert; Buhrley, Matthew; Wright, Kenneth; Shabahang, Shahrokh

2011-02-01

A growing body of evidence is demonstrating the possibility for regeneration of tissues within the pulp space and continued root development in teeth with necrotic pulps and open apices. There are areas of research related to regenerative endodontics that need to be investigated in an animal model. The purpose of this study was to investigate ferret cuspid teeth as a model to investigate factors involved in regenerative endodontics. Six young male ferrets between the ages of 36-133 days were used in this investigation. Each animal was anesthetized and perfused with 10% buffered formalin. Block sections including the mandibular and maxillary cuspid teeth and their surrounding periapical tissues were obtained, radiographed, decalcified, sectioned, and stained with hematoxylin-eosin to determine various stages of apical closure in these teeth. The permanent mandibular and maxillary cuspid teeth with open apices erupted approximately 50 days after birth. Initial signs of closure of the apical foramen in these teeth were observed between 90-110 days. Complete apical closure was observed in the cuspid teeth when the animals were 133 days old. Based on the experiment, ferret cuspid teeth can be used to investigate various factors involved in regenerative endodontics that cannot be tested in human subjects. The most appropriate time to conduct the experiments would be when the ferrets are between the ages of 50 and 90 days. Copyright © 2011. Published by Elsevier Inc.

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-04-01

Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Characterization of Coronal Pulp Cells and Radicular Pulp Cells in Human Teeth.

PubMed

Honda, Masaki; Sato, Momoko; Toriumi, Taku

2017-09-01

Dental pulp has garnered much attention as an easily accessible postnatal tissue source of high-quality mesenchymal stem cells (MSCs). Since the discovery of dental pulp stem cells (DPSCs) in permanent third molars, stem cells from human exfoliated deciduous teeth and from supernumerary teeth (mesiodentes) have been identified as a population distinct from DPSCs. Dental pulp is divided into 2 parts based on the developing stage: the coronal pulp and the radicular pulp. Root formation begins after the crown part is completed. We performed a sequential study to examine the differences between the characteristics of coronal pulp cells (CPCs) and radicular pulp cells (RPCs) from permanent teeth, mesiodentes, and deciduous teeth. Interestingly, although we have not obtained any data on the difference between CPCs and RPCs in permanent teeth, there are some differences between the characteristics of CPCs and RPCs from mesiodentes and deciduous teeth. The MSC characteristics differed between the RPCs and CPCs, and the reprogramming efficiency for the generation of induced pluripotent stem cells was greater in RPCs than in CPCs from deciduous teeth. The proportion of CD105 + cells in CPCs versus that in RPCs varied in mesiodentes but not in permanent teeth. The results indicate that the proportion of CD105 + cells is an effective means of characterizing dental pulp cells in mesiodentes. Taken together, the stem cells in deciduous and supernumerary teeth share many characteristics, such as a high proliferation rate and an immunophenotype similar to that of DPSCs. Thus, mesiodentes accidentally encountered on radiographs by the general dental practitioner might be useful for stem cell therapy. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Structure, attachment, replacement and growth of teeth in bluefish, Pomatomus saltatrix (Linnaeus, 1776), a teleost with deeply socketed teeth.

PubMed

Bemis, William E; Giuliano, Anne; McGuire, Betty

2005-01-01

Tooth replacement poses many questions about development, pattern formation, tooth attachment mechanisms, functional morphology and the evolution of vertebrate dentitions. Although most vertebrate species have polyphyodont dentitions, detailed knowledge of tooth structure and replacement is poor for most groups, particularly actinopterygians. We examined the oral dentition of the bluefish, Pomatomus saltatrix, a pelagic and coastal marine predator, using a sample of 50 individuals. The oral teeth are located on the dentary and premaxillary bones, and we scored each tooth locus in the dentary and premaxillary bones using a four-part functional classification: absent (A), incoming (I), functional (F=fully ankylosed) or eroding (E). The homodont oral teeth of Pomatomus are sharp, deeply socketed and firmly ankylosed to the bone of attachment. Replacement is intraosseus and occurs in alternate tooth loci with long waves of replacement passing from rear to front. The much higher percentage of functional as opposed to eroding teeth suggests that replacement rates are low but that individual teeth are quickly lost once erosion begins. Tooth number increases ontogenetically, ranging from 15-31 dentary teeth and 15-39 premaxillary teeth in the sample studied. Teeth increase in size with every replacement cycle. Remodeling of the attachment bone occurs continuously to accommodate growth. New tooth germs originate from a discontinuous dental lamina and migrate from the lingual (dentary) or labial (premaxillary) epithelium through pores in the bone of attachment into the resorption spaces beneath the existing teeth. Pomatomus shares unique aspects of tooth replacement with barracudas and other scombroids and this supports the interpretation that Pomatomus is more closely related to scombroids than to carangoids.

Assessing the oral microbiota of healthy and alcohol-treated rats using whole-genome DNA probes from human bacteria.

PubMed

Jabbour, Zaher; do Nascimento, Cássio; Kotake, Bruna Gabriela Dos Santos; El-Hakim, Michel; Henderson, Janet E; de Albuquerque Junior, Rubens Ferreira

2013-03-01

This study aimed to evaluate the capacity of whole-genome DNA probes prepared from human oral bacteria to cross-react with bacteria from the oral cavity of rats, and to assess the influence of alcohol ingestion on the animals' oral biofilm. Twenty four mature Wistar rats were equally divided in two groups. One group (control) was fed balanced diet of rat pellets and water. The alcohol-treated group (AT) received the same diet and 20% ethanol solution. Upon euthanasia after 30 days, bacterial samples from the oral biofilm covering the animals' teeth were collected using microbrushes. Bacteria identification and quantification were performed using the DNA checkerboard hybridization method with 33 probes prepared from human oral bacteria. Signals corresponding to bacterial genome counts and percentages were compared using a Mann-Whitney U test with a significance level <0.05. Cross-reaction for all targeted species, except Streptococcus mutans and Streptococcus mitis-like species, occurred in the control group. Escherichia coli, Pseudomonas aeruginosa, Porphyromonas endodontalis, and Veillonella parvula-like species only produced detectable signals in the AT group. Significantly more signals were detected in the control group compared to the AT group (p=0.001). The percentage of E. coli-like species was highest in both groups. Whole-genome DNA probes prepared from human oral bacteria can cross-react with rats' oral bacterial species. Alcohol consumption is associated with lower levels and diversity of bacterial species in the oral cavity of rats. Copyright © 2012 Elsevier Ltd. All rights reserved.

Lead line in rodents: an old sign of lead intoxication turned into a new method for environmental surveillance.

PubMed

de Figueiredo, Fellipe Augusto Tocchini; Ramos, Junia; Kawakita, Erika R Hashimoto; Bilal, Alina S; de Sousa, Frederico B; Swaim, William D; Issa, Joao P Mardegan; Gerlach, Raquel F

2016-11-01

The "lead line" was described by Henry Burton in 1840. Rodents are used as sentinels to monitor environmental pollution, but their teeth have not been used to determine lead. To determine whether lead deposits can be observed in the teeth of lead-exposed animals, since the gingival deposits known as "lead line" would likely have a correlate in the calcified tissue to which the gums are opposed during life. Male Wistar rats were exposed to lead in the drinking water (30 mg/L) since birth until 60 days-old. Molars and the incisors of each hemimandible were analyzed by scanning electron microscopy (SEM) on regular and backscattered electrons (BSE) mode. Elements were determined using electron dispersive spectroscopy (EDS). Clean cervical margins were observed on control teeth, as opposed to the findings of extensive deposits on lead-exposed animals, even in hemimandibles that had been exhumed after being buried for 90 days. BSE/EDS indicated that those deposits were an exogenous material compatible with lead sulfite. Presence of calcium, phosphorus, magnesium, carbon, lead, and oxygen is presented. Lead-exposed animals presented marked root resorption. The lead deposits characterized here for the first time show that the "lead line" seen in gums has a calcified tissue counterpart, that is detectable post-mortem even in animals exposed to a low dose of lead. This is likely a good method to detect undue lead exposure and will likely have wide application for pollution surveillance using sentinels.

Trigeminal pathways deliver a low molecular weight drug from the nose to the brain and orofacial structures.

PubMed

Johnson, Neil J; Hanson, Leah R; Frey, William H

2010-06-07

Intranasal delivery has been shown to noninvasively deliver drugs from the nose to the brain in minutes along the olfactory and trigeminal nerve pathways, bypassing the blood-brain barrier. However, no one has investigated whether nasally applied drugs target orofacial structures, despite high concentrations observed in the trigeminal nerve innervating these tissues. Following intranasal administration of lidocaine to rats, trigeminally innervated structures (teeth, temporomandibular joint (TMJ), and masseter muscle) were found to have up to 20-fold higher tissue concentrations of lidocaine than the brain and blood as measured by ELISA. This concentration difference could allow intranasally administered therapeutics to treat disorders of orofacial structures (i.e., teeth, TMJ, and masseter muscle) without causing unwanted side effects in the brain and the rest of the body. In this study, an intranasally administered infrared dye reached the brain within 10 minutes. Distribution of dye is consistent with dye entering the trigeminal nerve after intranasal administration through three regions with high drug concentrations in the nasal cavity: the middle concha, the maxillary sinus, and the choana. In humans the trigeminal nerve passes through the maxillary sinus to innervate the maxillary teeth. Delivering lidocaine intranasally may provide an effective anesthetic technique for a noninvasive maxillary nerve block. Intranasal delivery could be used to target vaccinations and treat disorders with fewer side effects such as tooth pain, TMJ disorder, trigeminal neuralgia, headache, and brain diseases.

Odontogenesis in the Veiled Chameleon (Chamaeleo calyptratus).

PubMed

Buchtová, Marcela; Zahradníček, Oldřich; Balková, Simona; Tucker, Abigail S

2013-02-01

Replacement teeth in reptiles and mammals develop from a successional dental lamina. In monophyodont (single generation) species such as the mouse, no successional lamina develops. We have selected a reptilian monophyodont species - the Veiled Chameleon (Chamaeleo calyptratus) - to investigate whether this is a common characteristic of species that do not have replacement teeth. Furthermore, we focus on the sequence of tooth initiation along the jaw, and tooth attachment to the bones. Embryos of the Veiled Chameleon were collected during the first 6 months of incubation (from the 5th to 24th week) at 7-day intervals. After five weeks of incubation, an epithelial thickening was present as a shallow protrusion into the mesenchyme. A week later, the epithelium elongated more deeply into the mesenchyme to form the dental lamina. The formation of all tooth germs along the jaw was initiated from the tip of the dental lamina. Development of a successional dental lamina was initiated during the pre-hatching period but this structure became markedly reduced during juvenile stages. MicroCT analysis showed the presence of a heterodont dentition in young chameleons with multicuspid teeth in the caudal jaw area and simpler monocuspid teeth rostrally. Unlike the pleurodont teeth of most reptilian species, chameleon teeth are acrodontly ankylosed to the bones of the jaw. Odontoblasts produced a layer of predentine that connected the dentine to the supporting bone, with both tooth and bone protruding out of the oral cavity and acting as a functional unit. Chameleons may provide new and useful information to study the molecular interaction at the tooth-bone interface in physiological as well as pathological conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths.

PubMed

Liu, Rui; Kaiwar, Anjali; Shemesh, Hagay; Wesselink, Paul R; Hou, Benxiang; Wu, Min-Kai

2013-01-01

The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. Two hundred forty mandibular incisors were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. The root canals were instrumented with rotary and hand files, namely K3, ProTaper, and nickel-titanium Flex K files to the major apical foramen (AF), short AF, or beyond AF. Digital images of the apical surface of every tooth were taken during the apical enlargement at each file change. Development of dentinal defects was determined by comparing these images with the baseline image. Multinomial logistic regression test was performed to identify influencing factors. Apical crack developed in 1 of 80 teeth (1.3%) with hand files and 31 of 160 teeth (19.4%) with rotary files. Apical dentinal detachment developed in 2 of 80 teeth (2.5%) with hand files and 35 of 160 teeth (21.9%) with rotary files. Instrumentation with rotary files terminated 2 mm short of AF and did not cause any cracks. Significantly less cracks and detachments occurred when instrumentation with rotary files was terminated short of AF, as compared with that terminated at or beyond AF (P < .05). The AF deviated from the anatomic apex in 128 of 240 teeth (53%). Significantly more apical dentinal detachments appeared in teeth with a deviated AF (P = .033). Rotary instruments caused more dentinal defects than hand instruments; instrumentation short of AF reduced the risk of dentinal defects. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Interspecies difference in placement of developing teeth and its relationship with cross-sectional geometry of the mandibular symphysis in four primate species including modern humans.

PubMed

Fukase, Hitoshi

2012-02-01

The form of the anthropoid mandibular symphysis has recently been addressed in association with spatial requirements for the forming anterior teeth. To evaluate potential relationships between the symphyseal shape and teeth further, the growth patterns of the symphyseal region and the positioning of the tooth crypts were examined using CT data, comparing four primate species (modern humans, chimpanzees, Japanese monkeys, and hamadryas baboons) with varied symphyseal curvature and tooth size. First, results showed that interspecies differences in overall mandibular shape including symphyseal inclination and bicanine width are consistently expressed throughout postnatal ontogeny, although local symphyseal configurations related to the superior transverse torus (STT) tended to change considerably during growth in chimpanzees. Second, the four species were found to exhibit differentiated formation positions of the incisor and canine crypts. In particular, I2 developed between I1 and C in humans with a broad bicanine space and small teeth, whereas it was positioned posterior to I1 and above C in the cercopithecines with an extremely narrow bicanine space. In chimpanzees, despite the large bicanine width, I1 and I2 grew with a large antero-posterior overlap owing to their large size. These results indicate that the dental positioning is determined in concert with the size balance of the available mandibular space and forming teeth. Finally, the positions/contours of I2 crypt were shown to correspond strongly with the STT across the taxa. This suggests that interspecies differences in symphyseal shape should be interpreted partially by the species-specific positional relationships of the developing anterior teeth. Copyright © 2011 Wiley Periodicals, Inc.

Loss of teeth and enamel in tetrapods: fossil record, genetic data and morphological adaptations

PubMed Central

Davit-Béal, Tiphaine; Tucker, Abigail S; Sire, Jean-Yves

2009-01-01

Since their recruitment in the oral cavity, approximately 450 million years ago, teeth have been subjected to strong selective constraints due to the crucial role that they play in species survival. It is therefore quite surprising that the ability to develop functional teeth has subsequently been lost several times, independently, in various lineages. In this review, we concentrate our attention on tetrapods, the only vertebrate lineage in which several clades lack functional teeth from birth to adulthood. Indeed, in other lineages, teeth can be absent in adults but be functionally present in larvae and juveniles, can be absent in the oral cavity but exist in the pharyngeal region, or can develop on the upper jaw but be absent on the lower jaw. Here, we analyse the current data on toothless (edentate) tetrapod taxa, including information available on enamel-less species. Firstly, we provide an analysis of the dispersed and fragmentary morphological data published on the various living taxa concerned (and their extinct relatives) with the aim of tracing the origin of tooth or enamel loss, i.e. toads in Lissamphibia, turtles and birds in Sauropsida, and baleen whales, pangolins, anteaters, sloths, armadillos and aardvark in Mammalia. Secondly, we present current hypotheses on the genetic basis of tooth loss in the chicken and thirdly, we try to answer the question of how these taxa have survived tooth loss given the crucial importance of this tool. The loss of teeth (or only enamel) in all of these taxa was not lethal because it was always preceded in evolution by the pre-adaptation of a secondary tool (beak, baleens, elongated adhesive tongues or hypselodonty) useful for improving efficiency in food uptake. The positive selection of such secondary tools would have led to relaxed functional constraints on teeth and would have later compensated for the loss of teeth. These hypotheses raise numerous questions that will hopefully be answered in the near future. PMID:19422426

The effect of Emdogain and 24% EDTA root conditioning on periodontal healing of replanted dog's teeth.

PubMed

Guzmán-Martínez, Nayelli; Silva-Herzog, Flores Daniel; Méndez, González Verónica; Martín-Pérez, Silvia; Cerda-Cristerna, Bernardino Isaac; Cohenca, Nestor

2009-02-01

Controversies still exist as for the regenerative role of enamel matrix derivatives and the need for removal of the periodontal ligament in replanted teeth. The purpose of this study was to evaluate the effect of Emdogain and 24% ethylenediamine tetraacetic acid (EDTA) root conditioning on periodontal healing of replanted dog's teeth. Teeth were extracted, endodontically treated and preconditioned as follows: group 1, Emdogain; group 2, Emdogain + EDTA and group 3, EDTA. Teeth were replanted after 30 min extraoral time, splinted for 15 days and animals sacrificed after 8 weeks of observation. Histological evaluation was performed using hematoxylin/eosin and Masson trichrome and results scored based on previously reported criteria for histological evaluation. Replacement root resorption was histologically diagnosed in all groups except in the negative control. A parametric analysis showed no statistically significant differences between experimental groups. Root preconditioning with Emdogain alone or in combination with 24% EDTA showed no evidence of regeneration of collagen fibers and consequently did not prevent the development of replacement root resorption on replanted dog's teeth.

The effect of dental bleaching on pulpal tissue response in a diabetic animal model.

PubMed

Cintra, L T A; Ferreira, L L; Benetti, F; Gastélum, A A; Gomes-Filho, J E; Ervolino, E; Briso, A L F

2017-08-01

To evaluate pulpal tissue response after dental bleaching in normal and alloxan-induced diabetic rats. Twenty-eight rats were divided into two groups of normoglycaemic and diabetic rats (n = 14). Diabetes mellitus (DM) was induced with alloxan. After DM confirmation, all rats were anaesthetized and dental bleaching was performed with 35% hydrogen peroxide (H 2 O 2 ) on the right maxillary molars for 30 min. Left molars were used as controls. Bleaching resulted in four hemimaxillae groups: normoglycaemic (N), N-bleached (NBle), diabetic (D) and D-bleached (DBle). After 2 or 30 days, the animals were euthanized and the hemimaxillae were removed, processed for histopathological analysis and stained with haematoxylin-eosin (HE), Masson's trichrome (MT) and picrosirius red (PSR). Results obtained within animals (normoglycaemic or diabetic rats) were submitted to Wilcoxon or paired t-tests, and between animal (normoglycaemic and diabetic rats), to Mann-Whitney test or t-tests. At 2 days, the NBle group had a mild inflammatory infiltration in the pulpal tissue, whilst the DBle had severe inflammation or necrosis (P < 0.05). At 30 days, no inflammation was present. However, a significant difference in pulp chamber area reduction by reactionary dentine deposition was found between the NBle and DBle groups (P < 0.05). At 2 days, fewer immature collagen fibres and more mature collagen fibres were noted in the NBle, D and DBle groups; this was significantly different when compared to the N group (P < 0.05). At 30 days, significantly fewer immature collagen fibres and more mature collagen fibres were noted in NBle compared with DBle group (P < 0.05). The inflammatory tissue response in rats' teeth after dental bleaching was greater in diabetic rats. Additionally, the increase in reactionary dentine deposition and mature collagen fibres observed in diabetic rats needs further evaluation to confirm the present results. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Relationship of intracanal medicaments to endodontic flare-ups.

PubMed

Trope, M

1990-10-01

The purpose of the study was to compare the effect of three intracanal medicaments on the incidence of post-instrumentation flare-ups. All teeth were instrumented to a predetermined minimum size using a 0.5% solution of sodium hypochlorite as the irrigant. Formocresol, Ledermix, and calcium hydroxide were placed in strict sequence irrespective of the presence or absence of symptoms or radiographic signs of apical periodontitis. The patients were given written post-operative instructions and a prescription for 600 mg ibuprofen to be taken if mild to moderate pain developed. If severe pain and/or swelling developed the patient was instructed to call the office immediately and was considered to have had a flare-up. Twelve flare-ups occurred in teeth with radiographic signs of apical periodontitis; none in teeth without periapical radiolucencies. Six of the twelve flare-ups occurred in retreatment cases and the other six occurred in teeth without previous endodontic treatment. No significant difference was found in the flare-up rate among the three intracanal medicaments.

Formation of oral and pharyngeal dentition in teleosts depends on differential recruitment of retinoic acid signaling

PubMed Central

Gibert, Yann; Bernard, Laure; Debiais-Thibaud, Melanie; Bourrat, Franck; Joly, Jean-Stephane; Pottin, Karen; Meyer, Axel; Retaux, Sylvie; Stock, David W.; Jackman, William R.; Seritrakul, Pawat; Begemann, Gerrit; Laudet, Vincent

2010-01-01

One of the goals of evolutionary developmental biology is to link specific adaptations to changes in developmental pathways. The dentition of cypriniform fishes, which in contrast to many other teleost fish species possess pharyngeal teeth but lack oral teeth, provides a suitable model to study the development of feeding adaptations. Here, we have examined the involvement of retinoic acid (RA) in tooth development and show that RA is specifically required to induce the pharyngeal tooth developmental program in zebrafish. Perturbation of RA signaling at this stage abolished tooth induction without affecting the development of tooth-associated ceratobranchial bones. We show that this inductive event is dependent on RA synthesis from aldh1a2 in the ventral posterior pharynx. Fibroblast growth factor (FGF) signaling has been shown to be critical for tooth induction in zebrafish, and its loss has been associated with oral tooth loss in cypriniform fishes. Pharmacological treatments targeting the RA and FGF pathways revealed that both pathways act independently during tooth induction. In contrast, we find that in Mexican tetra and medaka, species that also possess oral teeth, both oral and pharyngeal teeth are induced independently of RA. Our analyses suggest an evolutionary scenario in which the gene network controlling tooth development obtained RA dependency in the lineage leading to the cypriniforms. The loss of pharyngeal teeth in this group was cancelled out through a shift in aldh1a2 expression, while oral teeth might have been lost ultimately due to deficient RA signaling in the oral cavity.—Gibert, Y., Bernard, L., Debiais-Thibaud, M., Bourrat, F., Joly, J.-S., Pottin, K., Meyer, A., Retaux, S., Stock, D. W., Jackman, W. R., Seritrakul, P., Begemann, G., Laudet, V. Formation of oral and pharyngeal dentition in teleosts depends on differential recruitment of retinoic acid signaling. PMID:20445074

Fusobacterium nucleatum in endodontic flare-ups.

PubMed

Chávez de Paz Villanueva, Luis Eduardo

2002-02-01

The extent to which Fusobacterium nucleatum is recovered from root canals of teeth that present with an interappointment flare-up following endodontic instrumentation was investigated. Included in the study were 28 patients that sought emergency treatment after initiation of root canal therapy. Only non-painful teeth that had been treated because of a necrotic pulp and periapical inflammatory lesion were studied. Root canal samples for bacterial analysis were taken, transported to a bacteriological laboratory, and processed for a semiquantitative assessment of bacterial isolates. Bacterial findings were correlated with self-assessed pain intensity as recorded by means of a Visual Analogue Scale. Clinical presentation of swelling and presence of exudate in the treated root canals were also linked. Bacteria were recovered from all teeth examined. Gram-negative anaerobic coccoid rods (Prevotella species and Porphyromonas species) were frequent isolates. All teeth in patients who were reported to be in severe pain (Visual Analogue Scale > or = 6) displayed F nucleatum. Nine out of 10 of these teeth also had swelling and exudate in the root canals. Samples from the remaining patients that had teeth with less pain score showed a variable bacterial recovery. None of these teeth displayed F nucleatum. F nucleatum appears to be associated with the development of the most severe forms of interappointment endodontic flare-ups.

Guidance of eruption for general practitioners.

PubMed

Ngan, Peter W; Kao, Elizabeth C; Wei, Stephen H

2003-04-01

The principle of early treatment through well-planned extraction of primary teeth followed by removal of permanent teeth has stood the test of time. The objective of this article is to develop some simple guidelines for general dental practitioners to perform 'guidance of eruption' in malocclusion with severe crowding.

Histological evaluation of direct pulp capping of rat pulp with experimentally developed low-viscosity adhesives containing reparative dentin-promoting agents.

PubMed

Suzuki, Masaya; Taira, Yoshihisa; Kato, Chikage; Shinkai, Koichi; Katoh, Yoshiroh

2016-01-01

This study examines the wound healing process in exposed rat pulp when capped with experimental adhesive resin systems. Experimental adhesive resin system for direct pulp capping was composed of primer-I (PI), -II (PII), and -III (PIII) and an experimental bonding agent (EBA). PI was Clearfil(®) SE Bond(®)/Primer (CSP) containing 5.0 wt% CaCl2, PII was PI containing 10 wt% nanofiller (Aerosil(®) 380), and PIII was CSP containing 5.0 wt% of compounds of equal moles of synthetic peptides (pA and pB) derived from dentin matrix protein 1. EBA was Clearfil(®) SE Bond(®)/Bond (CSB) containing 10 wt% hydroxyapatite powders. Three experimental groups were designed. PI was assigned to experimental Groups 1 and 3. PII was assigned to experimental Groups 2 and 3. PIII and EBA were assigned to all experimental adhesive groups. Control teeth were capped with calcium hydroxide preparation (Dycal(®)), and CSP and CSB were applied to the cavity. The rats were sacrificed after each observation period (14, 28, 56, and 112 days). The following parameters were evaluated: pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation (RDF), and bacterial penetration. There were no significant differences among all the groups for all parameters and all observation periods (p>0.05, Kruskal-Wallis test). All groups showed initial RDF at 14 days postoperatively and extensive RDF until 112 days postoperatively. Groups 2 and 3 demonstrated higher quantity of mineralized dentin bridge formation compared with Group 1. Addition of nanofillers to the primer was effective in promoting high-density RDF. Experimentally developed adhesive resin systems induce the exposed pulp to produce almost the same quantity of reparative dentin as calcium hydroxide. However, we need further studies to elucidate whether the same results could be obtained in humans. Copyright © 2015 Elsevier Ltd. All rights reserved.

Root End Generation: An Unsung Characteristic Property of MTA-A Case Report

PubMed Central

Dixit, Seema; Dixit, Ashutosh; Kumar, Pravin; Arora, Saurabh

2014-01-01

Management of immature teeth with necrotic pulp and periapical lesion has long presented a challenge. The treatment of choice for such teeth is apexification, which is induction of apical closure to produce more favorable conditions for conventional canal obturation. Traditionally, calcium hydroxide has been used for the apexification of immature permanent teeth, however, Mineral Trioxide Aggregate (MTA) holds significant promise not only as an alternative to multiple treatment visits with calcium hydroxide but also having the potential to induce root end development, eventually forming a completed root apex. This case report presents a successful healing and apexification with the use of calcium hydroxide and MTA. A 5-year follow-up revealed root development with MTA. PMID:24596800

Confocal laser scanning microscopy in study of bone calcification

NASA Astrophysics Data System (ADS)

Nishikawa, Tetsunari; Kokubu, Mayu; Kato, Hirohito; Imai, Koichi; Tanaka, Akio

2012-12-01

Bone regeneration in mandible and maxillae after extraction of teeth or tumor resection and the use of rough surface implants in bone induction must be investigated to elucidate the mechanism of calcification. The calcified tissues are subjected to chemical decalcification or physical grinding to observe their microscopic features with light microscopy and transmission electron microscopy where the microscopic tissue morphology is significantly altered. We investigated the usefulness of confocal laser scanning microscopy (CLSM) for this purpose. After staggering the time of administration of calcein and alizarin red to experimental rats and dogs, rat alveolar bone and dog femur grafted with coral as scaffold or dental implants were observed with CLSM. In rat alveolar bone, the calcification of newly-formed bone and net-like canaliculi was observed at the mesial bone from the roots progressed at the rate of 15 μm/day. In dog femur grafted with coral, newly-formed bones along the space of coral were observed in an orderly manner. In dog femur with dental implants, after 8 weeks, newly-formed bone proceeded along the rough surface of the implants. CLSM produced high-magnification images of newly-formed bone and thin sections were not needed.

Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

NASA Astrophysics Data System (ADS)

El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

2011-12-01

In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

An animal model of intrinsic dental erosion caused by gastro-oesophageal reflux disease.

PubMed

Higo, T; Mukaisho, K; Ling, Z-Q; Oue, K; Chen, K-H; Araki, Y; Sugihara, H; Yamamoto, G; Hattori, T

2009-07-01

To explore the association between dental erosion and gastro-oesophageal reflux disease (GORD), we used an animal model of GORD. We performed an operation to force gastro-duodenal contents reflux in male Wistar rats, and examined the teeth in the reflux rats at 15 or 30 weeks postoperatively. Dental erosion was evaluated based on a slightly modified index from a previous report. Estimation of pH was employed in the oesophageal and gastric contents. Macroscopically, dental erosion was only detected in the reflux rats. Histopathologically, dentin exposure was detected in three of the seven cases after 30 weeks. Alveolar bone destruction and osteomyelitis were also noted in severe cases. The pH of the oesophageal and stomach contents was 6.93 +/- 0.15 and 3.7 +/- 0.39, respectively. We confirmed the relationship between dental erosion and GORD. First step of dental erosion caused by GORD is the loss of surface enamel induced by regurgitation of an acidic liquid and acidic gas. Subsequently, further destruction of dental hard tissues and tooth supporting structure is accelerated by mixed juice with gastric and duodenal contents. The reflux animal model is a useful tool to examine the mechanism of dental erosion in GORD.

Dental development of Didelphis albiventris (Marsupialia): I--incisors and canines.

PubMed

Fonseca, C T; Alves, J B

2006-02-01

The formation of incisors and canines in marsupials of D. albiventris was studied at various stages of development. Seventy-six specimens, with ages varying from 0 to 100 days, were used in this investigation. Serial sections of the maxilla were obtained in the transverse plane and stained with hematoxylin and eosin. Histological analyses were made to verify the pattern of teeth development, as well as their chronology of eruption. The period of time from birth to 100 days comprised the entire process of teeth development, from epithelial bud formation to early eruption of the teeth. Oral epithelium thickening gave rise to the functional incisors and canines. In addition, a secondary dental lamina emerged in different phases of development in the outer epithelium of incisors and canines, which degenerated when it reached the bud stage. No evidence of deciduous dentition was observed. The results of this investigation suggest that secondary dental lamina represents remnants of a primitive condition in which secondary dentition used to be present.

Attenuation of Morphine-Induced Tolerance and Dependence by Pretreatment with Cerebrolysin in Male rats.

PubMed

Ghavimi, Hamed; Darvishi, Sara; Ghanbarzadeh, Saeed

2018-01-01

Dependence and tolerance to morphine are major problems which limit its chronic clinical application. This study was aimed to investigate the attenuation effect of Cerebrolysin, a mixture of potent growth factors (BDNF, GDNF, NGF, CNTF etc,), on the development of Morphine-induced dependence and tolerance. Male Wistar rats were selected randomly and divided into different groups (n=8) including: a control group, groups received additive doses of morphine (5-25 mg/kg, ip, at an interval of 12 h until tolerance completion), and groups pretreated with Cerebrolysin (40, 80 and 160 mg/kg, ip, before morphine administration). Development of tolerance was assessed by tail-flick test and the attenuation effect of Cerebrolysin on morphine-induced dependence was evaluated after injection of naloxone (4 mg/kg, ip, 12 h after the morning dose of morphine). Seven distinct withdrawal signs including: jumping, rearing, genital grooming, abdominal writhing, wet dog shake and teeth grinding were recorded for 45 min and total withdrawal score (TWS) was calculated. Results showed that administration of Cerebrolysin could prolonged development (10 and 14 days in administration of 80 mg/kg and 160 mg/kg Cerebrolysin) and completion (4, 10 and 14 days in administration of 40, 80 and 160 mg/kg Cerebrolysin, respectively) of tolerance. Results also indicated that administration of Cerebrolysin (40, 80 and 160 mg/kg) could significantly decreased the TWS value (62±2, 77±4 and 85±6%, respectively). In conclusion, it was found that pretreatment with Cerebrolysin could attenuated morphine-induced tolerance and dependence. © Georg Thieme Verlag KG Stuttgart · New York.

About Kids' Teeth

MedlinePlus

... Kids’ Teeth Teeth Helpful Resources Links About Kids’ Teeth We have two sets of teeth during life: ... usually appeared. Learn about Nutrition Baby Teething Baby Teeth and Teething Baby teeth usually appear when your ...

Evaluation of radiographs, clinical signs and symptoms associated with pulp canal obliteration: an aid to treatment decision.

PubMed

Oginni, Adeleke O; Adekoya-Sofowora, Comfort A; Kolawole, Kikelomo A

2009-12-01

Pulp canal obliteration (PCO) is a sequela of tooth trauma. The dental clinician faced with this condition has to make a difficult decision. The aim of this study was to evaluate the clinical signs and symptoms associated with teeth with PCO and to assess the status of the periapical tissues using the periapical index (PAI) as an aid in making a treatment decision. The study included teeth diagnosed with PCO in patients with a history of traumatic injury to the involved teeth. Histories of associated signs and symptoms including pain, swelling and drainage from a sinus tract were elicited. Tooth color, sensibility to electric pulp testing, mobility and percussion tenderness were recorded. The periapical status was assessed using the PAI. Two hundred and seventy-six teeth were diagnosed with PCO. One hundred and fifty-seven (56.9%) and 119 (43.1%) demonstrated partial or total PCO, respectively. Yellow discoloration presented most frequently, occurring in 186 (67.4%) teeth. Sixty-two (33.3%) of these had developed periapical lesions and reacted negatively to sensibility testing. Fifty-seven (30.7%) of these teeth presented radiographically with a normal periapical appearance and reacted normally to sensibility testing, whereas 67 (36.0%) presented with small changes in the periapical bone pattern and reacted in the high normal range to sensibility testing. Teeth with PAI scores < or =2 presented with occasional spontaneous pain. Teeth with PAI scores > or =3 presented with clinical symptoms and signs ranging from pain on percussion to spontaneous pain, and slight swelling to sinus tract drainage. Based on the findings of this study, endodontic treatment should be initiated in teeth with tenderness to percussion, PAI scores > or =3 and a negative response to sensibility testing.

Dental Fluorosis and Catalase Immunoreactivity of the Brain Tissues in Rats Exposed to High Fluoride Pre- and Postnatally.

PubMed

Güner, Şirin; Uyar-Bozkurt, Süheyla; Haznedaroğlu, Eda; Menteş, Ali

2016-11-01

This study evaluated dental fluorosis of the incisors and immunoreactivity in the brain tissues of rats given chronic fluoride doses pre- and postnatally. Female rats were given drinking water with 0, 30 or 100 ppm fluoride ad libitum throughout gestation and the nursing period. In addition, 63 male offspring were treated with the same water regimens as the mothers after weaning and were followed for 1, 3 or 5 months. The upper and lower incisors were collected, and all teeth were examined under a stereomicroscope and scored by two blinded examiners using a modified rodent enamel fluorosis index. Cortical, hippocampal and cerebellar brain samples were evaluated morphologically and immunohistochemically. All fluoride-treated pups were born with low body weight (p = 0.001). All animals from the fluoride groups had enamel fluorosis with defects of various degrees. The increase in the dental fluorosis scores in the fluoride treatment groups was significant (p < 0.01). The catalase immunoreactivity in the 30- and 100-ppm fluoride groups was significantly higher than that in the controls after 1, 3 and 5 months (p < 0.001). In conclusion, this study showed that rats with dental fluorosis had catalase immunoreactivity in the brain tissues, which may reflect the neurobehavioral toxicity of fluoride.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats

PubMed Central

Busato, Mauro Carlos Agner; Pereira, Alex Luiz Pozzobon; Sonoda, Celso Koogi; Cuoghi, Osmar Aparecido; de Mendonça, Marcos Rogério

2014-01-01

Objective The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). Methods Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n = 5), according to the combination of variables: Group 1 - control (neither trauma nor ITM); Group 2 - ITM; Groups 3, 4, 5 and 6 - dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. Results In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. Conclusion There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma. PMID:24713565

Does systemic administration of casein phosphopeptides affect orthodontic movement and root resorption in rats?

PubMed

Crowther, Lachlan; Shen, Gang; Almuzian, Mohammed; Jones, Allan; Walsh, William; Oliver, Rema; Petocz, Peter; Tarraf, Nour E; Darendeliler, M Ali

2017-10-01

To assess the potential effects of casein phosphopeptides (CPPs) on orthodontically induced iatrogenic root resorption (OIIRR) and orthodontic teeth movement. Forty Wistar rats (aged 11 weeks) were randomly divided into experimental group (EG; n = 20) that received a diet supplemented with CPP and control group (CG; n = 20) devoid of diet supplement. A 150 g force was applied using nickel titanium (NiTi) coil that was bonded on maxillary incisors and extended unilaterally to a maxillary first molar. At Day 28, animals in both groups were euthanized. Volumetric assessment of root resorption craters and linear measurement of maxillary first molars movement were blindly examined using a micro-computed tomography scan. Nine rats were excluded from the experiment due to loss during general anesthesia or appliances' failure. Intra-operator reproducibility was high in both volumetric and linear measurements, 92.8 per cent and 98.5-97.6 per cent, respectively. The results reveal that dietary CPP has statistically insignificant effect on the overall OIIRR and orthodontic movement. CPP seems to have statistically insignificant effect on the volume of OIIRR and orthodontic movement in rats. A long-term study with larger sample size using a different concentration of CPP is required to clarify the dentoalveolar effect of CPP. © The Author 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com

Ar+ and CuBr laser-assisted chemical bleaching of teeth: estimation of whiteness degree

NASA Astrophysics Data System (ADS)

Dimitrov, S.; Todorovska, Roumyana; Gizbrecht, Alexander I.; Raychev, L.; Petrov, Lyubomir P.

2003-11-01

In this work the results of adaptation of impartial methods for color determination aimed at developing of techniques for estimation of human teeth whiteness degree, sufficiently handy for common use in clinical practice are presented. For approbation and by the way of illustration of the techniques, standards of teeth colors were used as well as model and naturally discolored human teeth treated by two bleaching chemical compositions activated by three light sources each: Ar+ and CuBr lasers, and a standard halogen photopolymerization lamp. Typical reflection and fluorescence spectra of some samples are presented; the samples colors were estimated by a standard computer processing in RGB and B coordinates. The results of the applied spectral and colorimetric techniques are in a good agreement with those of the standard computer processing of the corresponding digital photographs and complies with the visually estimated degree of the teeth whiteness judged according to the standard reference scale commonly used in the aesthetic dentistry.

Bioengineered Tooth Buds Exhibit Features of Natural Tooth Buds.

PubMed

Smith, E E; Angstadt, S; Monteiro, N; Zhang, W; Khademhosseini, A; Yelick, P C

2018-06-01

Tooth loss is a significant health issue currently affecting millions of people worldwide. Artificial dental implants, the current gold standard tooth replacement therapy, do not exhibit many properties of natural teeth and can be associated with complications leading to implant failure. Here we propose bioengineered tooth buds as a superior alternative tooth replacement therapy. We describe improved methods to create highly cellularized bioengineered tooth bud constructs that formed hallmark features that resemble natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation. These constructs were composed of postnatal dental cells encapsulated within a hydrogel material that were implanted subcutaneously into immunocompromised rats. To our knowledge, this is the first report describing the use of postnatal dental cells to create bioengineered tooth buds that exhibit evidence of these features of natural tooth development. We propose future bioengineered tooth buds as a promising, clinically relevant tooth replacement therapy.

Rotary endodontics in primary teeth – A review

PubMed Central

George, Sageena; Anandaraj, S.; Issac, Jyoti S.; John, Sheen A.; Harris, Anoop

2015-01-01

Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the “gold-standard” over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel–titanium (Ni–Ti) rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel–titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed. PMID:26792964

Rotary endodontics in primary teeth - A review.

PubMed

George, Sageena; Anandaraj, S; Issac, Jyoti S; John, Sheen A; Harris, Anoop

2016-01-01

Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the "gold-standard" over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel-titanium (Ni-Ti) rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel-titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed.

Tooth loss in 1535 treated periodontal patients.

PubMed

Nabers, C L; Stalker, W H; Esparza, D; Naylor, B; Canales, S

1988-05-01

Of 1535 treated recall patients surveyed over an average time of 12.9 years since treatment was completed, 1371 had lost no teeth from periodontal disease. The total number of teeth lost was 444, with the average tooth loss for the 1535 patients being 0.29. In the three full arch splinted cases, the loss rate was 14.67 teeth per patient. Patients treated without any excisional or flap surgical procedures made up 26.5% of those surveyed, whereas 73.5% had required various surgical procedures. No attempt was made to compare different pocket therapy procedures. Although many patients developed recurrent periodontal problems during recall, only 15.9% of the 1535 patients required surgical retreatment. Teeth that were originally given a doubtful prognosis often were responsible for recurrent problems and sometimes required extraction.

Long-term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats.

PubMed

Avivi-Arber, Limor; Lee, Jye-Chang; Sood, Mandeep; Lakschevitz, Flavia; Fung, Michelle; Barashi-Gozal, Maayan; Glogauer, Michael; Sessle, Barry J

2015-11-01

Tooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face-M1) and adjacent primary somatosensory cortex (face-S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face-M1 and face-S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1-2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS-evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P < 0.05) and sustained (1-2 months) decreased number of ICMS-defined jaw and tongue sites within face-M1 and -S1, and increased thresholds of ICMS-evoked responses in these sites. Furthermore, dental implant placement reversed the extraction-induced changes in face-S1, and in face-M1 the number of jaw sites even increased as compared to naive rats. These novel findings suggest that face-M1 and adjacent face-S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants. © 2015 Wiley Periodicals, Inc.

Pulp Cell Tracking by Radionuclide Imaging for Dental Tissue Engineering

PubMed Central

Souron, Jean-Baptiste; Petiet, Anne; Decup, Franck; Tran, Xuan Vinh; Lesieur, Julie; Poliard, Anne; Le Guludec, Dominique; Letourneur, Didier; Chaussain, Catherine; Rouzet, Francois

2014-01-01

Pulp engineering with dental mesenchymal stem cells is a promising therapy for injured teeth. An important point is to determine the fate of implanted cells in the pulp over time and particularly during the early phase following implantation. Indeed, the potential engraftment of the implanted cells in other organs has to be assessed, in particular, to evaluate the risk of inducing ectopic mineralization. In this study, our aim was to follow by nuclear imaging the radiolabeled pulp cells after implantation in the rat emptied pulp chamber. For that purpose, indium-111-oxine (111In-oxine)-labeled rat pulp cells were added to polymerizing type I collagen hydrogel to obtain a pulp equivalent. This scaffold was implanted in the emptied pulp chamber space in the upper first rat molar. Labeled cells were then tracked during 3 weeks by helical single-photon emission computed tomography (SPECT)/computed tomography performed on a dual modality dedicated small animal camera. Negative controls were performed using lysed radiolabeled cells obtained in a hypotonic solution. In vitro data indicated that 111In-oxine labeling did not affect cell viability and proliferation. In vivo experiments allowed a noninvasive longitudinal follow-up of implanted living cells for at least 3 weeks and indicated that SPECT signal intensity was related to implanted cell integrity. Notably, there was no detectable systemic release of implanted cells from the tooth. In addition, histological analysis of the samples showed mitotically active fibroblastic cells as well as neoangiogenesis and nervous fibers in pulp equivalents seeded with entire cells, whereas pulp equivalents prepared from lysed cells were devoid of cell colonization. In conclusion, our study demonstrates that efficient labeling of pulp cells can be achieved and, for the first time, that these cells can be followed up after implantation in the tooth by nuclear imaging. Furthermore, it appears that grafted cells retained the label and are viable to follow the repair process. This technique is expected to be of major interest for monitoring implanted cells in innovative therapies for injured teeth. PMID:23789732

Enamel biorhythms of humans and great apes: the Havers-Halberg Oscillation hypothesis reconsidered.

PubMed

Mahoney, Patrick; Miszkiewicz, Justyna J; Pitfield, Rosie; Deter, Chris; Guatelli-Steinberg, Debbie

2017-02-01

The Havers-Halberg Oscillation (HHO) hypothesis links evidence for the timing of a biorhythm retained in permanent tooth enamel (Retzius periodicity) to adult body mass and life history traits across mammals. Potentially, these links provide a way to access life history of fossil species from teeth. Recently we assessed intra-specific predictions of the HHO on human children. We reported Retzius periodicity (RP) corresponded with enamel thickness, and cusp formation time, when calculated from isolated deciduous teeth. We proposed the biorhythm might not remain constant within an individual. Here, we test our findings. RP is compared between deciduous second and permanent first molars within the maxillae of four human children. Following this, we report the first RPs for deciduous teeth from modern great apes (n = 4), and compare these with new data for permanent teeth (n = 18) from these species, as well as with previously published values. We also explore RP in teeth that retain hypoplastic defects. Results show RP changed within the maxilla of each child, from thinner to thicker enameled molars, and from one side of a hypoplastic defect to the other. When considered alongside correlations between RP and cusp formation time, these observations provide further evidence that RP is associated with enamel growth processes and does not always remain constant within an individual. RP of 5 days for great ape deciduous teeth lay below the lowermost range of those from permanent teeth of modern orangutan and gorilla, and within the lowermost range of RPs from chimpanzee permanent teeth. Our data suggest associations between RP and enamel growth processes of humans might extend to great apes. These findings provide a new framework from which to develop the HHO hypothesis, which can incorporate enamel growth along with other physiological systems. Applications of the HHO to fossil teeth should avoid transferring RP between deciduous and permanent enamel, or including hypoplastic teeth. © 2016 Anatomical Society.

Recommendations for using regenerative endodontic procedures in permanent immature traumatized teeth.

PubMed

Garcia-Godoy, Franklin; Murray, Peter E

2012-02-01

The regeneration of immature permanent teeth following trauma could be beneficial to reduce the risk of fracture and loss of millions of teeth each year. Regenerative endodontic procedures include revascularization, partial pulpotomy, and apexogenesis. Several case reports give these procedures a good prognosis as an alternative to apexification. Care is needed to deliver regenerative endodontic procedures that maintain or restore the vitality of teeth, but which also disinfect and remove necrotic tissues. Regeneration can be accomplished through the activity of the cells from the pulp, periodontium, vascular, and immune system. Most therapies use the host's own pulp or vascular cells for regeneration, but other types of dental stem cell therapies are under development. There are no standardized treatment protocols for endodontic regeneration. The purpose of this article is to review the recent literature and suggest guidelines for using regenerative endodontic procedures for the treatment of permanent immature traumatized teeth. Recommendations for the selection of regenerative and conventional procedures based on the type of tooth injury, fracture type, presence of necrosis or infection, periodontal status, presence of periapical lesions, stage of tooth development, vitality status, patient age, and patient health status will be reviewed. Because of the lack of long-term evidence to support the use of regenerative endodontic procedures in traumatized teeth with open apices, revascularization regeneration procedures should only be attempted if the tooth is not suitable for root canal obturation, and after apexogenesis, apexification, or partial pulpotomy treatments have already been attempted and have a poor prognosis. © 2011 John Wiley & Sons A/S.

Prosthodontic Treatment Using Vital and Non Vital Submerged Roots-Two Case Reports

PubMed Central

Shankar, Y. Ravi; Srinivas, K.; Surapaneni, Hemchand; Reddy, S.V. Sudhakar

2013-01-01

Residual ridge resorption has been considered as an inevitable consequence after extraction of the teeth. There is a gradual loss of the alveolar bone due to the pattern of bone remodeling. In spite of the availability of newer treatment modalities like endodontic restoration and periodontic procedures for preservation of the remaining teeth they are not feasible for the patients in severe stages where restoration might not be possible. The only reliable method of preserving the remaining bone is by maintaining the functional health of the teeth. Over the years, many studies showed that roots which are fractured and left behind during extractions are retained into the alveolar bone with no evidence of pathosis. Over denture as a treatment option was developed in an effort to preserve the remaining alveolar bone by retaining the natural teeth or roots. In over denture treatment, the teeth selected as abutments are prone to caries and periodontal disease over a period of time, hence evolved the vital or non vital root submergence concept. After a thorough radiographic and clinical examination, few teeth without pathosis are retained that eventually are surgically submerged in the alveolar ridge. After healing, the over denture with reaining vital or non vital teeth preserve the integrity of the bone, making the treatment an effective and successfull preventive prosthodontic treatment. PMID:24298542

A model for extending the reach of the traditional dental practice: the ForsythKids program.

PubMed

Niederman, Richard; Gould, Ellen; Soncini, Jennifer; Tavares, Mary; Osborn, Valarie; Goodson, J Max

2008-08-01

The authors describe and evaluate the short-term effectiveness of a community-based program for dental caries prevention in children. The authors enrolled pupils in the ForsythKids program after receiving informed consent. They targeted children at six Massachusetts elementary schools, grades 1 through 3, with pupil populations at high risk of developing caries. The children underwent examination by dentists using calibrated technique and received comprehensive preventive care from dental hygienists. The authors determined effectiveness by means of comparing results of the initial examination with those of a second examination performed six months later. At baseline, 70 percent of the 1,196 participating children had decayed or filled teeth. More troublingly, 42.1 percent of the primary teeth and 31.1 percent of the permanent teeth had untreated decay. Six months after preventive intervention, the proportion of teeth with new decay was reduced 52 percent in primary teeth and 39 percent in permanent teeth. Furthermore, the percentage of children with newly decayed or restored primary and permanent teeth was reduced by 25.4 percent and 53.2 percent, respectively. These results indicate that this care model relatively quickly can overcome multiple barriers to care and improve children's oral health. If widely implemented, comprehensive caries prevention programs such as ForsythKids could accomplish national health goals and reduce the need for new care providers and clinics.

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

The Effect of Chemically Modified Tetracycline-3 on the Progression of Dental Caries in Rats.

PubMed

Xu, Jun; Miao, Congcong; Tian, Zhenchuan; Li, Jinlu; Zhang, Chunmei; Yang, Dongmei

2018-02-07

Matrix metalloproteinases (MMPs) exist in human saliva and dentin and play an important role in the degradation of organic matrix in teeth. Chemically modified tetracycline-3 (CMT-3) is an inhibitor of MMPs. CMT-3 has been used experimentally to treat caries since 1999, but no distinction between dental caries prevalence and dentin caries prevalence has been described. A total of 65 Sprague-Dawley rats were randomly divided into three groups. The positive control group (25 rats) was inoculated with Streptococcus mutans (ATCC700610) and fed the cariogenic feed of improved Keyes Diet 2000. The CMT-3 group (25 rats) was also inoculated with S. mutans and fed the cariogenic feed of improved Keyes Diet 2000; the surfaces of rats' molars were daily treated with 0.02% CMT-3. The negative control group (15 rats) was only fed the standard rodent chow. At the end of the 10th week, the dental caries prevalence and dentin caries prevalence of each group were calculated, and the regions of caries were assessed. No caries was found in the negative control group. The dental caries prevalence of the CMT-3 and the positive control group was 75.0 and 83.3%, respectively (p > 0.05, Table 2). The dentin caries prevalence of the CMT-3 and the positive control group was 33.3 and 70.8%, respectively (p < 0.05, Table 2). The Keyes scoring of dentin caries in the CMT-3 group was significantly lower than that in the positive control group (p < 0.05, Table 3). CMT-3 had no effect on the prevalence of dental caries, but could lower the prevalence and slow down the progression of dentin caries. © 2018 S. Karger AG, Basel.

Changes in root length during orthodontic treatment: advantages for immature teeth.

PubMed

Mavragani, Maria; Bøe, Olav Egil; Wisth, Per Johan; Selvig, Knut Andreas

2002-02-01

The purpose of the study was to investigate root lengthening during orthodontic treatment in relation to the age of the patient, the developmental stage of the root, and the anticipated growth. Specifically, the potential benefit of treating young teeth was addressed. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars, and edgewise technique with 0.018-inch slot brackets. Additionally, a cross-sectional control group of 66 untreated individuals matched to gender, and pre- and post-treatment age of the experimental group was included. Crown and root lengths of the maxillary incisors were measured on peri-apical radiographs before and after treatment, and corrected for image distortion. The stage of root development before treatment was recorded. Root elongation during treatment was found for 50 out of the 280 examined teeth. Age at treatment start was significantly higher among the patients showing root shortening of the lateral incisors during treatment than among those showing root elongation (P < 0.05). The stage of root development was significantly related to the direction of root length change, i.e. shortening or elongation. Roots elongated during treatment did not differ in length from untreated teeth of similarly aged individuals. There was no significant difference in the extent of root lengthening between the roots elongated during treatment and the normal root lengthening in age-matched untreated individuals. Post-treatment root length was significantly related to pre-treatment age. Roots that were incompletely developed before treatment reached a significantly greater length than those that were fully developed at the start of treatment. The results of this study show a definite advantage for younger teeth with regard to post-treatment root length. This finding may influence treatment planning strategy.

An amelogenin mutation leads to disruption of the odontogenic apparatus and aberrant expression of Notch I

PubMed Central

Chen, Xu; Li, Yong; Alawi, Faizan; Bouchard, Jessica R.; Kulkarni, Ashok B.; Gibson, Carolyn W.

2012-01-01

BACKGROUND Amelogenins are highly conserved proteins secreted by ameloblasts in the dental organ of developing teeth. These proteins regulate dental enamel thickness and structure in humans and mice. Mice that express an amelogenin transgene with a P70T mutation (TgP70T) develop abnormal epithelial proliferation in an amelogenin null (KO) background. Some of these cellular masses have the appearance of proliferating stratum intermedium, which is the layer adjacent to the ameloblasts in unerupted teeth. As Notch proteins are thought to constitute the developmental switch that separates ameloblasts from stratum intermedium, these signaling proteins were evaluated in normal and proliferating tissues. METHODS Mandibles were dissected for histology and immunohistochemistry using Notch I antibodies. Molar teeth were dissected for western blotting and RT-PCR for evaluation of Notch levels through imaging and statistical analyses. RESULTS Notch I was immunolocalized to ameloblasts of TgP70TKO mice, KO ameloblasts stained, but less strongly, and wild-type teeth had minimal staining. Cells within the proliferating epithelial cell masses were positive for Notch I and had an appearance reminiscent of calcifying epithelial odontogenic tumor with amyloid-like deposits. Notch I protein and mRNA were elevated in molar teeth from TgP70TKO mice. CONCLUSION Expression of TgP70T leads to abnormal structures in mandibles and maxillae of mice with the KO genetic background and these mice have elevated levels of Notch I in developing molars. As cells within the masses also express transgenic amelogenins, development of the abnormal proliferations suggests communication between amelogenin producing cells and the proliferating cells, dependent on the presence of the mutated amelogenin protein. PMID:20923441

Subgingival Microbiome Colonization and Cytokine Production during Early Dental Implant Healing.

PubMed

Payne, Jeffrey B; Johnson, Paul G; Kok, Car Reen; Gomes-Neto, João C; Ramer-Tait, Amanda E; Schmid, Marian J; Hutkins, Robert W

2017-01-01

Little is known about longitudinal development of the peri-implant subgingival microbiome and cytokine production as a new sulcus forms after dental implant placement. Therefore, the purpose of this observational study was to evaluate simultaneous longitudinal changes in the oral microbiome and cytokine production in the developing peri-implant sulcus compared to control natural teeth. Four and 12 weeks after implant placement and abutment connection, a dental implant and a natural tooth were sampled in 25 patients for subgingival plaque and gingival crevicular fluid (GCF [around teeth] and peri-implant crevicular fluid [PICF] around implants). DNA from plaque samples was extracted and sequenced using Illumina-based 16S rRNA sequencing. GCF and PICF samples were analyzed using a customized Milliplex human cytokine and chemokine magnetic bead panel. Beta diversity analysis revealed that natural teeth and implants had similar subgingival microbiomes, while teeth had greater alpha diversity than implants. At the genus level, however, few differences were noted between teeth and dental implants over 12 weeks. Specifically, Actinomyces and Selenomonas were significantly elevated around teeth versus dental implants at both 4 weeks and 12 weeks, while Corynebacterium and Campylobacter were significantly elevated only at 4 weeks around teeth. The only difference between PICF and GCF biomarkers was significantly elevated granulocyte-macrophage colony-stimulating factor levels around teeth versus dental implants at the 4-week visit. The subgingival microbiome and cytokine production were similar between teeth and implants during early healing, suggesting that these profiles are driven by the patient following dental implant placement and are not determined by anatomical niche. IMPORTANCE Dental implants are a common treatment option offered to patients for tooth replacement. However, little is known regarding initial colonization of the subgingival microbiome and simultaneous longitudinal cytokine production in humans during the early healing phase following implant placement. We report findings from an in vivo study that assessed initial colonization of the subgingival microbiome and concomitant early cytokine production in a newly formed anatomical space, namely, an implant sulcus. This approach may be useful in future interventional studies to influence dental implant success. Our data showed that the subgingival microbiome and cytokine profile were similar for control natural teeth and dental implants at both 4 and 12 weeks after implant placement. These data suggest that these profiles are driven by the patient and not by anatomical location (i.e., tooth versus dental implant).

Periodontal healing by periodontal ligament cell sheets in a teeth replantation model.

PubMed

Zhou, Yefang; Li, Yusheng; Mao, Ling; Peng, Hao

2012-02-01

Successful transplantation of avulsed teeth is to restore the attachment and regenerate the periodontal support. Different strategies have been applied in treatment from modification of teeth storage, antibiotic usage to peridontium tissue replacement. We developed a novel periodontal ligament cell-sheet delivery system to apply on delayed replanted teeth in promoting periodontal healing in a canine model. Autologous periodontal ligament (PDL) fibroblasts were isolated from extracted premolars of beagle dog. The cell-sheets were fabricated using normal culture dish after stimulation of extracellular matrix formation. Teeth were surgically extracted and attached soft tissues were removed. After root canal treatment, the root of teeth were wrapped by the PDL cell-sheets and replanted back to prior socket accordingly whilst teeth without cell sheets as a control. Eight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Regeneration of periodontal tissue was evaluated through histology assay. Multi-layered PDL cell-sheet could be attached on tooth root and most cells on sheet-tooth constructs were viable before replantation. Minimum clinical signs of inflammation were observed in experiment. PDL cell-sheets group show significant higher occurrence of favourable healing (88.4%) than control group with low healing (5.3%). Periodontal ligament and cememtum tissue regeneration was observed in the experimental group, and the regenerated tissues showed high collagen type III, type I and fibronectin expression. The periodontal ligament cell-sheets fabricated through normal cell culture dish has a potential for regeneration of periodontal ligament and may become a novel therapy for avulsed teeth replantation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (Gobiidiae: Sicydiinae) during cranial metamorphosis at the time of river recruitment.

PubMed

Sahara, Noriyuki; Moriyama, Keita; Iida, Midori; Watanabe, Shun

2016-06-01

The present study was aimed at elucidating the time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (S. japonicus) during cranial metamorphosis at the time of river recruitment. Fishes were caught at the post-larval stage at a river mouth and maintained for 7 days in a water tank. Each of 10 specimens was evaluated every day for 7 days by using microcomputed tomography, scanning electron microscopy, and light microscopy with peculiar attention to the development of the upper jaw teeth. Fishes caught at the river mouth were mostly transparent, with a rostral terminal mouth, and no teeth could be found in either the upper or lower jaw. At 2 days after collection, the mouth position changed from terminal to subterminal, resulting from a change in head shape. The initial eruption of first functional teeth was detected at the anterior two-thirds region of each upper jaw. These teeth erupted in adjacent positions, most had a tricuspid crown, and they represented miniature versions of adult teeth. At 5 days, the position of the mouth became further relocated from terminal rostral to ventral. The number of erupted teeth increased, followed by spreading of them anteriorly and posteriorly. At 7 days, they formed a single row of close-set tricuspid teeth along the entire length of each upper jaw. The present study demonstrated that even under laboratory conditions a rapid and drastic cranial metamorphosis took place within a week after the time of collection of post-larval S. japonicus from a river. The eruption of first functional teeth in the upper jaw of S. japonicus, which teeth are adapted to scraping algae off the substrate, was initially detected at 2 days after collection, and first functional dentition of the upper jaw was set up within 7 days after it. Copyright © 2016 Elsevier Ltd. All rights reserved.

p63 protein is essential for the embryonic development of vibrissae and teeth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rufini, Alessandro; Weil, Miguel; McKeon, Frank

2006-02-17

Development of skin appendages strongly depends on epithelial-mesenchymal interactions. One of the genes involved in this process is p63, a member of the p53 family of transcription factors, essential for ectodermal development, as elucidated by the phenotype of p63 knock-out mice. Surprisingly, no information on p63 expression in tooth and hair is yet available. Here, we show p63 expression during teeth and vibrissae morphogenesis in mouse embryos and we also show a correlation with the expression patterns of the epithelial marker keratin 5 and the proliferation marker Ki67. Our results show that p63 colocalizes with both K5 and Ki67 inmore » the epithelium of developing vibrissae, while in teeth p63 is expressed, together with K5, in the undifferentiated ectoderm (enamel organ), and in ameloblasts, a subpopulation of differentiated ectodermal cells. Moreover, p63 expression in tooth seems not to be fully colocalized with nuclear Ki67 expression.« less

The development and production of thermo-mechanically forged tool steel spur gears

NASA Technical Reports Server (NTRS)

Bamberger, E. N.

1973-01-01

A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

Effect of Er,Cr:YSGG laser irradiation on eruption of rat mandibular incisor after disturbance of the enamel organ in the pulp.

PubMed

Masuda, Yoshiko Murakami; Hossain, Mozammal; Wang, Xiaogu; Matsuoka, Emi; Okano, Tomohiro; Matsumoto, Koukichi

2006-09-01

To investigate the efficacy of Er,Cr:YSGG (erbium,chromium:yttrium scandium gallium garnet) laser irradiation in root canal preparation and to evaluate its effect on eruption of rat incisors after disturbance of the enamel organ in the pulp, 20 canals of lower left incisor teeth were prepared by K-files followed by Er,Cr:YSGG laser irradiation, and 20 canals of right incisors were subjected to K-files only (control). At 1 week after irradiation, both sides of incisors erupted at the same level from the gingival margin. Histological findings showed that laser irradiation produced a slightly larger damage in the pulp than that of control. Scanning electron microscope observation revealed that laser-treated surface revealed a rough, irregular, and very clean surface; there was almost no evidence of debris or smear layer, and dentinal tubules were opened. Adequate power of Er,Cr:YSGG laser irradiation is effective in root canal preparation without disturbance of the eruption.

Growth and development of permanent teeth germ of transplacental Yu-Cheng babies in Taiwan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lan, Shoujen; Yen, Yeayin; Ko, Yingchin

This paper is intended to present a study of transplacental Yu-Cheng babies in Taiwan. The focus of the study is to demonstrate how a contaminated food source can affect the growth and development of permanent teeth germ in children. A sporadic outbreak of a peculiar skin disease was reported in Japan in October of 1968. An epidemiological study revealed the outbreak of this disease was caused by contaminated Kanemi rice oil. This episode of rice oil poisoned with polychlorinated biphenyls (PCB) was the first reported outbreak of PCB poisoning in the world. A second episode occurred in central Taiwan elevenmore » years after the Japanese episode. Registered data from the Taiwan Provincial Government Health Department reported 1,843 cases in 1980. Of this group, more than 800 women were child-bearing age and most of these women would or soon would be married and pregnant. The offsprings of these women were in danger, because it has been proven that PCB intoxication could affect the fetus. These babies, only contaminated through the placenta, are called PCB transplacental Yusho babies in Japan and PCB transplacental Yu-Cheng babies in Taiwan. Babies with PCB poisoning could have Fetal PCB syndrome (FPS) and may have retarded eruption of permanent teeth and other anomalies such as reduced numbers of teeth and abnormal shaped roots. The study of transplacental Yu-Cheng babies is an important public health issue for Taiwan. Although there may be other issues, this study focuses only on the growth and development of permanent teeth of those babies affected by PCB transplacental contamination.« less

Evolutionary origins and development of saw-teeth on the sawfish and sawshark rostrum (Elasmobranchii; Chondrichthyes)

PubMed Central

Welten, Monique; Smith, Moya Meredith; Underwood, Charlie; Johanson, Zerina

2015-01-01

A well-known characteristic of chondrichthyans (e.g. sharks, rays) is their covering of external skin denticles (placoid scales), but less well understood is the wide morphological diversity that these skin denticles can show. Some of the more unusual of these are the tooth-like structures associated with the elongate cartilaginous rostrum ‘saw’ in three chondrichthyan groups: Pristiophoridae (sawsharks; Selachii), Pristidae (sawfish; Batoidea) and the fossil Sclerorhynchoidea (Batoidea). Comparative topographic and developmental studies of the ‘saw-teeth’ were undertaken in adults and embryos of these groups, by means of three-dimensional-rendered volumes from X-ray computed tomography. This provided data on development and relative arrangement in embryos, with regenerative replacement in adults. Saw-teeth are morphologically similar on the rostra of the Pristiophoridae and the Sclerorhynchoidea, with the same replacement modes, despite the lack of a close phylogenetic relationship. In both, tooth-like structures develop under the skin of the embryos, aligned with the rostrum surface, before rotating into lateral position and then attaching through a pedicel to the rostrum cartilage. As well, saw-teeth are replaced and added to as space becomes available. By contrast, saw-teeth in Pristidae insert into sockets in the rostrum cartilage, growing continuously and are not replaced. Despite superficial similarity to oral tooth developmental organization, saw-tooth spatial initiation arrangement is associated with rostrum growth. Replacement is space-dependent and more comparable to that of dermal skin denticles. We suggest these saw-teeth represent modified dermal denticles and lack the ‘many-for-one’ replacement characteristic of elasmobranch oral dentitions. PMID:26473044

Evaluation of Teeth Development in Unilateral Cleft Lip and Palate Patients in Mixed Dentition by Using Medical Image Control Systems.

PubMed

Gezgin, O; Botsali, M S

2018-02-01

The aim of this study was to evaluate the crown and root development in patients with cleft lip and palate using medical software programmes. In our study, 25 patients with mixed dentition unilateral cleft lip and palate were examined with cone-beam computed tomography (CBCT). The tomography images obtained as high resolution medical images on the computer control system (MIMICS 15.0, Materialise, Leuven, Belgium and SOLIDWORKS 2014 Premium, Concord, Massachusetts) were converted to three-dimensional volumetric images. These three-dimensional images of the cleft on the sides of the teeth in the crown and root growth were measured by mesiodistal length and crown/root rate with volume and area. These measurements were compared with a control group of healthy individuals. There were no statistically significant differences in the volume, surface area and MD size, crown/root ratio of central incisor, canine, first premolar and second premolar teeth within defect, and healthy teeth. However, it was found that there was a significant difference between the volume, surface area and MD size, and crown/root ratio of the lateral teeth in each group. In particular, among patients with cleft lip and palate, on obtaining a solid model of the tooth structure by using these programs, tooth development can be examined in more detail, diagnosis can be made more reliable, as well as in treatment planning. We believe that these programs can be used to resolve certain limitations such as a lack of an application to be used in routine dental treatment and in particular the need to do more study.

Formation of bone-like mineralized matrix by periodontal ligament cells in vivo: a morphological study in rats.

PubMed

Hiraga, Toru; Ninomiya, Tadashi; Hosoya, Akihiro; Takahashi, Masafumi; Nakamura, Hiroaki

2009-01-01

Periodontal ligament (PDL) is a unique connective tissue that not only connects cementum and alveolar bone to support teeth, but also plays an important role in reconstructing periodontal tissues. Previous studies have suggested that PDL cells have osteogenic potential; however, they lack precise histological examinations. Here, we studied bone-like matrix formation by PDL cells in rats using morphological techniques. Rat and human PDL cells exhibited substantial alkaline phosphatase activity and induced mineralization in vitro. RT-PCR analyses showed that PDL cells expressed the osteoblast markers, Runx2, osterix, and osteocalcin. These results suggest that PDL cells share similar phenotypes with osteoblasts. To examine the bone-like matrix formation in vivo, PDL cells isolated from green fluorescent protein (GFP)-transgenic rats were inoculated with hydroxyapatite (HA) disks into wild-type rats. Five weeks after the implantation, the pores in HA disks were occupied by GFP-positive cells. Mineralized matrix formation was also found on the surface of HA pores. At 12 weeks, some of the pores were filled with bone-like mineralized matrices (BLMM), which were positive for the bone matrix proteins, osteopontin, bone sialoprotein, and osteocalcin. Immunohistochemical examination revealed that most of the osteoblast- and osteocyte-like cells on or in the BLMM were GFP-positive, suggesting that the BLMM were directly formed by the inoculated PDL cells. On the pore surfaces, Sharpey's fiber-like structures embedded in cementum-like mineralized layers were also observed. These results collectively suggest that PDL cells have the ability to form periodontal tissues and could be a useful source for regenerative therapies of periodontal diseases.

Standing intraoral extractions of cheek teeth aided by partial crown removal in 165 horses (2010-2016).

PubMed

Rice, M K; Henry, T J

2018-01-01

Diseased cheek teeth in horses often require invasive extraction techniques that carry a high rate of complications. Techniques and instrumentation were developed to perform partial crown removal to aid standing intraoral extraction of diseased cheek teeth in horses. To analyse success rates and post-surgical complications in horses undergoing cheek teeth extraction assisted by partial crown removal. Retrospective cohort study. This study included 165 horses with 194 diseased cheek teeth that were extracted orally assisted by partial crown removal between 2010 and 2016. Medical records were analysed, including case details, obtained radiographs, surgical reports and follow-up information. Follow-up information (≥2 months) was obtained for 151 horses (91.5%). There were 95 horses examined post-operatively by the authors and, 16 horses by the referring veterinarian; in 40 horses, post-operative follow up was obtained by informal telephone interviews with the owner. Successful standing intraoral extraction of cheek teeth was obtained in 164/165 horses (99.4%). Twenty-five of these horses (15.2%) required additional intraoral extraction methods to complete the extraction, including minimally invasive transbuccal approach (n = 21) and tooth sectioning (n = 4). There was one (0.6%) horse with intraoral extraction failure that required standing repulsion to complete the extraction. The intraoperative complication of fractured root tips occurred in 11/165 horses (6.7%). Post-operative complications occurred in 6/165 horses (3.6%), including alveolar sequestra (n = 4), mild delay of alveolar healing at 2 months (n = 1), and development of a persistent draining tract secondary to a retained root tip (n = 1). Specialised instrumentation and additional training in the technique are recommended to perform partial crown removal in horses. Horses with cheek teeth extraction by partial crown removal have an excellent prognosis for a positive outcome. The term partial coronectomy is proposed for this technique. © 2017 EVJ Ltd.

Prevalence of white spot lesion formation during orthodontic treatment.

PubMed

Julien, Katie C; Buschang, Peter H; Campbell, Phillip M

2013-07-01

To quantify the prevalence of white spot lesions (WSLs) on the anterior teeth and, secondarily, to evaluate risk factors and predictors. Digital photographs and records of 885 randomly chosen patients were evaluated before and after treatment. Chart information included gender, age, as well as banding and debanding dates. Fluorosis and oral hygiene before and after treatment were also evaluated. Preexisting and posttreatment WSLs were recorded and compared for all 12 anterior teeth. Risk ratios (RR) and absolute risk (AR) were calculated to determine the likelihood and risk of WSL formation. Overall, 23.4% of the patients developed at least one WSL during their course of treatment. Maxillary anterior teeth were affected more than mandibular teeth. The maxillary laterals and canines and the mandibular canines were the most susceptible. There was no significant difference in WSLs between genders. Fluorosis, treatment time in excess of 36 months, poor pretreatment hygiene, hygiene changes during treatment, and preexisting WSLs were all significantly (P < .05) related to the development of WSLs. The highest risk of developing WSLs was associated with preexisting WSLs (RR = 3.40), followed by declines in oral hygiene during treatment (RR = 3.12) and poor pretreatment oral hygiene (RR = 2.83). Nearly 25% of the patients developed WSLs while in treatment, depending on fluorosis, treatment time, preexisting WSLs, and oral hygiene. Orthodontists need to be mindful of these risk factors when making treatment decisions.

Rate and pattern of interproximal dental attrition.

PubMed

Sarig, Rachel; Hershkovitz, Israel; Shpack, Nir; May, Hila; Vardimon, Alexander D

2015-08-01

Although occlusal and interproximal attrition occur because of diverse etiology and present dissimilar features, both progress with age. The objectives of this study were to reveal the rate and pattern of development of interproximal attrition facets (PAF) with age and to compare those with occlusal attrition (OA) changes. Five-hundred and ninety-four teeth were collected from 198 skulls (of adults, 20-71 yr of age). Three mandibular teeth [first premolar (P1), second premolar (P2), and first molar (M1)] were examined for PAF size and OA rate. Interproximal attrition and OA followed similar patterns of development until subjects reached 40-45 yr of age, after which they took different paths: PAF did not increase in size and were not as large as in younger groups, regardless of facet location, whereas OA continued to progress. The PAF changes with age differed between premolars and molars, unlike OA, which presented a similar rate for all teeth studied. Although OA scores presented significantly moderate correlations with age, PAF area size demonstrated low correlations with age. Low, but significant, correlations were found between the rate of OA and that of PAF. However, PAF and OA exhibited different patterns of development with age. Premolars and molars presented dissimilar development of PAF, which is probably caused by a unique attrition pattern in the molar teeth, different morphology, and force vectors. © 2015 Eur J Oral Sci.

Distinct developmental genetic mechanisms underlie convergently evolved tooth gain in sticklebacks

PubMed Central

Ellis, Nicholas A.; Glazer, Andrew M.; Donde, Nikunj N.; Cleves, Phillip A.; Agoglia, Rachel M.; Miller, Craig T.

2015-01-01

Teeth are a classic model system of organogenesis, as repeated and reciprocal epithelial and mesenchymal interactions pattern placode formation and outgrowth. Less is known about the developmental and genetic bases of tooth formation and replacement in polyphyodonts, which are vertebrates with continual tooth replacement. Here, we leverage natural variation in the threespine stickleback fish Gasterosteus aculeatus to investigate the genetic basis of tooth development and replacement. We find that two derived freshwater stickleback populations have both convergently evolved more ventral pharyngeal teeth through heritable genetic changes. In both populations, evolved tooth gain manifests late in development. Using pulse-chase vital dye labeling to mark newly forming teeth in adult fish, we find that both high-toothed freshwater populations have accelerated tooth replacement rates relative to low-toothed ancestral marine fish. Despite the similar evolved phenotype of more teeth and an accelerated adult replacement rate, the timing of tooth number divergence and the spatial patterns of newly formed adult teeth are different in the two populations, suggesting distinct developmental mechanisms. Using genome-wide linkage mapping in marine-freshwater F2 genetic crosses, we find that the genetic basis of evolved tooth gain in the two freshwater populations is largely distinct. Together, our results support a model whereby increased tooth number and an accelerated tooth replacement rate have evolved convergently in two independently derived freshwater stickleback populations using largely distinct developmental and genetic mechanisms. PMID:26062935

Teeth eruption in children with normal occlusion and malocclusion.

PubMed

Legović, Mario; Legović, Asja; Slaj, Martina; Mestrović, Senka; Lapter-Varga, Marina; Slaj, Mladen

2008-06-01

The aim of this study was to assess the differences in eruption of permanent teeth (C, P1, P2 and M2) in a group of children with and without malocclusion. A sample of 1758 children (921 boys and 837 girls), aged 8-13 was randomly selected. The subjects were grouped by chronological age (11 groups) and by presence of malocclusion. Statistically significant differences were found for both, upper and lower canines in the age group 11 (p<0.01). Statistically significant difference was found in the age group 8.5 for upper first (p<0.05), upper second premolars (p<0.01) in the age group 10, and the lower second premolars in the age group 11 (p<0.05). Premature loss of deciduous teeth caused early eruption of succedaneus permanent teeth, possibly leading to development of a malocclusion.

An ancient dental gene set governs development and continuous regeneration of teeth in sharks.

PubMed

Rasch, Liam J; Martin, Kyle J; Cooper, Rory L; Metscher, Brian D; Underwood, Charlie J; Fraser, Gareth J

2016-07-15

The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

False Teeth Still a Public Health Problem among Children in Kanungu District--South Western Uganda 2006

ERIC Educational Resources Information Center

Stephen, Sebudde

2006-01-01

False teeth among children are a Public Health problem which has not received adequate attention in Uganda. This study was therefore developed as a community-based descriptive cross-sectional carried out in Kanungu District using qualitative methods of data collection among caregivers of children, Community Owned Resource Persons and Service…

Ancient whales did not filter feed with their teeth.

PubMed

Hocking, David P; Marx, Felix G; Fitzgerald, Erich M G; Evans, Alistair R

2017-08-01

The origin of baleen whales (Mysticeti), the largest animals on Earth, is closely tied to their signature filter-feeding strategy. Unlike their modern relatives, archaic whales possessed a well-developed, heterodont adult dentition. How these teeth were used, and what role their function and subsequent loss played in the emergence of filter feeding, is an enduring mystery. In particular, it has been suggested that elaborate tooth crowns may have enabled stem mysticetes to filter with their postcanine teeth in a manner analogous to living crabeater and leopard seals, thereby facilitating the transition to baleen-assisted filtering. Here we show that the teeth of archaic mysticetes are as sharp as those of terrestrial carnivorans, raptorial pinnipeds and archaeocetes, and thus were capable of capturing and processing prey. By contrast, the postcanine teeth of leopard and crabeater seals are markedly blunter, and clearly unsuited to raptorial feeding. Our results suggest that mysticetes never passed through a tooth-based filtration phase, and that the use of teeth and baleen in early whales was not functionally connected. Continued selection for tooth sharpness in archaic mysticetes is best explained by a feeding strategy that included both biting and suction, similar to that of most living pinnipeds and, probably, early toothed whales (Odontoceti). © 2017 The Authors.

The effect of root canal preparation on the development of dentin cracks.

PubMed

Milani, Amin Salem; Froughreyhani, Mohammad; Rahimi, Saeed; Jafarabadi, Mohammad Asghari; Paksefat, Sara

2012-01-01

Root fracture is not an instant phenomenon but a result of gradual development of tiny craze lines in tooth structure. Recent studies have shown that canal instrumentation has the potential to cause dentinal cracks. The purpose of this study was to evaluate and compare the formation of dentinal cracks caused by ProTaper rotary system to hand instrumentation. This in vitro study was carried out using 57 mandible incisor teeth. The teeth were decoronated. The roots were then examined to exclude cracked samples. A standard model for PDL simulation was used. The teeth were randomly divided into two experimental and one control group (n=19). The teeth in the experimental groups were prepared using hand or ProTaper Universal rotary instrumentation. The teeth in the control group were left unprepared. The teeth were then sectioned horizontally 3 and 6 mm from the apex, and the number of various dentinal defects was recorded using a dental operating microscope. The differences between groups were analyzed with Fisher's exact test. The hand group demonstrated significantly more defects than the control group (P=0.001). However, there was no significant difference between the rotary compared to the control and hand groups (P>0.05). There was no significant difference between groups with regards to fracture (P>0.05). Other defects including internal, external and surface cracks were more frequent in the hand than in the control or rotary groups (P=0.02), but the difference was not significant between the rotary and control groups (P>0.05). Canal preparation, whether hand or rotary, produces structural defects in dentin. The ProTaper rotary system when used according to the manufacturer's instructions, tends to produce fewer cracks and can be considered a safe preparation technique.

The Effect of Multiple Sulfatase Deficiency (MSD) on Dental Development: Can We Use the Teeth as an Early Diagnostic Tool?

PubMed

Zilberman, Uri; Bibi, Haim

2016-01-01

Multiple sulfatase deficiency (MSD) is a rare autosomal recessive inborn error of metabolism due to reduced catalytic activity of the different sulfatase. Affected individuals show neurologic deterioration with mental retardation, skeletal anomalies, organomegaly, and skin changes as in X-linked ichthyosis. The only organ that was not examined in MSD patients is the dentition. To evaluate the effect of the metabolic error on dental development in a patient with the intermediate severe late-infantile form of MSD (S155P). Histological and chemical study were performed on three deciduous and five permanent teeth from MSD patient and pair-matched normal patients. Tooth germ size and enamel thickness were reduced in both deciduous and permanent MSD teeth, and the scalloping feature of the DEJ was missing in MSD teeth causing enamel to break off from the dentin. The mineral components in the enamel and dentin were different. The metabolic error insults the teeth in the stage of organogenesis in both the deciduous and permanent dentition. The end result is teeth with very sharp cusp tips, thin hypomineralized enamel, and exposed dentin due to the break off of enamel. These findings are different from all other types of MPS syndromes.Clinically the phenotype of intermediate severe late-infantile form of MSD appeared during the third year of life. In children of parents that are carriers, we can diagnose the disease as early as birth using X-ray radiograph of the anterior upper region or as early as 6-8 months when the first deciduous tooth erupt and consider very early treatment to ameliorate the symptoms.

Malocclusion of teeth

MedlinePlus

Crowded teeth; Misaligned teeth; Crossbite; Overbite; Underbite; Open bite ... Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). The upper teeth should fit slightly over the lower teeth. ...

The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography

PubMed Central

2012-01-01

Background Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. Results Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth ≤5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth ≤5 years. A segmented pulp system was found in 72% of the investigated teeth. Segmentation into separate mesial and distal pulp compartments was most commonly present. Pulp horn 4 coalesced either with the mesial pulp horns 1 and 3 or with the distal pulp horns 2 and 5. Conclusions Details of the pulpar anatomy of equine cheek teeth are provided, supporting the continuous advancement in endodontic therapy. Numerous individual configurations of the pulp system were obtained in maxillary cheek teeth, but much less variability was seen in mandibular cheek teeth. PMID:23006500

Dental Aspect of Distal Tubular Renal Acidosis with Genu Valgum Secondary to Rickets: A Case Report

PubMed Central

Bahadure, Rakesh N.; Thosar, Nilima; Kriplani, Ritika; Baliga, Sudhindra; Fulzele, Punit

2012-01-01

Distal renal tubular acidosis is a disease that occurs when the kidneys do not remove acid properly into the urine, leaving the blood too acidic (called acidosis). Distal renal tubular acidosis (type I RTA) is caused by a defect in the kidney tubes that causes acid to build up in the bloodstream. It ultimately results rickets which include chronic skeletal pain, in skeletal deformities, skeletal fractures. Rickets is among the most frequent childhood diseases in many developing countries. Dental problems in rickets include delayed eruption of permanent teeth, premature fall of deciduous teeth, defects in structure of teeth, enamel defects in permanent teeth (hypoplastic), pulp defects, intraglobular dentine, and caries tooth. Herewith, reported a case of distal tubular renal acidosis with genu valgum secondary to rickets, with pain and extraoral swelling associated with right and left mandibular 1st permanent molars. Teeth were infected with pulp without being involved with caries. Radiographically cracks in enamel and dentin were observed. Pulp revascularization with 46 and root canal treatment was done for 36 with followup of 1 year. PMID:22567455

Distalization of Maxillary First Permanent Molar by Pendulum Appliance in Mixed Dentition Period.

PubMed

Paranna, Sujatha; Shetty, Prakashchandra; Anandakrishna, Latha; Rawat, Anuradha

2017-01-01

Mesial drifting of molar teeth in maxillary arch is corrected by movement of the molars distally. In addition to traditional distal movement techniques, such as extraoral force application and removable appliances, various intra-arch devices have been introduced since 1980s. These intra-arch appliances have nearly eliminated the need for patient cooperation. The purpose of this paper is to report a case of 10-year-old male patient with loss of space in maxillary molar teeth treated by intra-arch appliance-pendulum appliance by distalization of maxillary first permanent molar teeth. Distaliza-tion of the permanent molar teeth helped in proper eruption of second premolar teeth without any extensive treatment procedures. In the present case report, the treatment of developing malocclusion was corrected by utilizing the concept of interceptive orthodontics. Hence, correction of space loss in mixed dentition period using pendulum appliance can eliminate the fixed orthodontic therapy. Paranna S, Shetty P, Anandakrishna L, Rawat A. Distalization of Maxillary First Permanent Molar by Pendulum Appliance in Mixed Dentition Period. Int J Clin Pediatr Dent 2017;10(3):299-301.

Majewski osteodysplastic primordial dwarfism type II: clinical findings and dental management of a child patient

PubMed Central

Terlemez, Arslan; Altunsoy, Mustafa; Celebi, Hakki

2015-01-01

Majewski osteodysplastic primordial dwarfism type II (MOPD II) is an unusual autosomal recessive inherited form of primordial dwarfism, which is characterized by a small head diameter at birth, but which also progresses to severe microcephaly, progressive bony dysplasia, and characteristic facies and personality. This report presents a case of a five-year-old girl with MOPD II syndrome. The patient was referred to our clinic with the complaint of severe tooth pain at the left mandibular primary molar teeth. Clinical examination revealed that most of the primary teeth had been decayed and all primary teeth were hypoplastic. Patient’s history revealed delayed development in the primary dentition and radiographic examination showed rootless primary molar teeth and short-rooted incisors. The treatment was not possible due to the lack of root of the left mandibular primary molars; so the teeth were extracted. Thorough and timely dental evaluation is crucial for the prevention of dental problems and the maintenance of oral health in patients with MOPD II syndrome is of utmost importance. PMID:28955524

Teeth: Among Nature's Most Durable Biocomposites

NASA Astrophysics Data System (ADS)

Lawn, Brian R.; Lee, James J.-W.; Chai, Herzl

2010-08-01

This paper addresses the durability of natural teeth from a materials perspective. Teeth are depicted as smart biocomposites, highly resistant to cumulative deformation and fracture. Favorable morphological features of teeth at both macroscopic and microscopic levels contribute to an innate damage tolerance. Damage modes are activated readily within the brittle enamel coat but are contained from spreading catastrophically into the vulnerable tooth interior in sustained occlusal loading. Although tooth enamel contains a multitude of microstructural defects that can act as sources of fracture, substantial overloads are required to drive any developing cracks to ultimate failure—nature's strategy is to contain damage rather than avoid it. Tests on model glass-shell systems simulating the basic elements of the tooth enamel/dentin layer structure help to identify important damage modes. Fracture and deformation mechanics provide a basis for analyzing critical conditions for each mode, in terms of characteristic tooth dimensions and materials properties. Comparative tests on extracted human and animal teeth confirm the validity of the model test approach and point to new research directions. Implications in biomechanics, especially as they relate to dentistry and anthropology, are outlined.

Majewski osteodysplastic primordial dwarfism type II: clinical findings and dental management of a child patient.

PubMed

Terlemez, Arslan; Altunsoy, Mustafa; Celebi, Hakki

2015-01-01

Majewski osteodysplastic primordial dwarfism type II (MOPD II) is an unusual autosomal recessive inherited form of primordial dwarfism, which is characterized by a small head diameter at birth, but which also progresses to severe microcephaly, progressive bony dysplasia, and characteristic facies and personality. This report presents a case of a five-year-old girl with MOPD II syndrome. The patient was referred to our clinic with the complaint of severe tooth pain at the left mandibular primary molar teeth. Clinical examination revealed that most of the primary teeth had been decayed and all primary teeth were hypoplastic. Patient's history revealed delayed development in the primary dentition and radiographic examination showed rootless primary molar teeth and short-rooted incisors. The treatment was not possible due to the lack of root of the left mandibular primary molars; so the teeth were extracted. Thorough and timely dental evaluation is crucial for the prevention of dental problems and the maintenance of oral health in patients with MOPD II syndrome is of utmost importance.

Demystifying the Mysteries: Sexual Dimorphism in Primary Teeth.

PubMed

Singh, Akshara; Bhatia, Hind Pal; Sood, Shveta; Sharma, Naresh

2017-04-01

One of the critical steps in the process of identification is the sex determination of an unknown individual. Many studies have shown that sex can be determined using the human skeleton, especially by examining the pelvis and skull. Odontometric analysis of the human sexual variation has been less investigated, especially of primary dentition. To verify the presence of sexual dimorphism in primary teeth of local population of Faridabad, Haryana, India. The research was performed on dental casts of 500 children (250 boys and 250 girls, age range 3-5 years). Mesiodistal and buccolingual crown dimensions of maxillary and mandibular primary teeth were measured with a digital Vernier's caliper and were analysed for sexual dimorphism. Mann-Whitney-U test was used to check the statistical significance of difference in tooth dimensions among boys and girls. Differences were found in the mean values of mesiodistal and buccolingual diameters of primary teeth, in which boys generally had larger crown diameters than girls. Primary teeth may be used as an additional tool for sex identification of juvenile skeletons where other dimorphic features are not much developed.

Morphometric, densitometric and mechanical properties of mandibular deciduous teeth in 5-month-old Polish Merino sheep

PubMed Central

2014-01-01

Background Caries, enamel hypoplasia, molar incisor hipomineralization, amylogenesis imperfecta, dentine dysplasia, hypophosphatasia and other dental disorders lead to tooth mineralization disturbances and structural abnormalities, decreasing masticatory organ functions. Dental disorders in sheep can lead to premature slaughter before they have attained final stage of their reproductive life and induce economic loss due to high flock replacement costs. Growth rate, health status and meat quality of sheep depends on tooth properties and quality determining in large extent efficiency of the masticatory apparatus and initial food break up. Considering lack of basic anatomical and physiological data on teeth properties in sheep, the aim of the study was to evaluate morphometric, densitometric and mechanical traits of deciduous mandibular incisor, canine and the second premolar obtained at the slaughter age of 5 months of life. Results The obtained results have shown the highest values of weight, total tooth volume, enamel volume and dentine volume in second premolar. Morphometric and mechanical parameters of incisors reached the highest values in first incisor and decreased gradually in second and third incisor, and in canine. Densitometric measurements have not revealed significant differences of the volumetric tooth mineral density in hard dental tissues between the investigated teeth. Conclusions In conclusion, proposed methodological approach is noninvasive since the deciduous teeth undergo physiological replacement with permanent teeth. Deciduous teeth can be easy collected for analyses from large animal population and may reflect mineral status and metabolism resulting from postnatal growth and development of the whole flock. In individual cases, evaluation of properties of deciduous teeth may serve for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory system functions. PMID:24548814

Relative tooth size at birth in primates: Life history correlates.

PubMed

Smith, Timothy D; Muchlinski, Magdalena N; Bucher, Wade R; Vinyard, Christopher J; Bonar, Christopher J; Evans, Sian; Williams, Lawrence E; DeLeon, Valerie B

2017-11-01

Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. Newborn primates were studied using serial histological sectioning. Volumes of deciduous premolars (dp 2 -dp 4 ), replacement teeth (if any), and permanent molars (M 1-2/3 ) of the upper jaw were measured and residuals from cranial length were calculated with least squares regressions to obtain relative dental volumes (RDVs). Relative dental volumes of deciduous or permanent teeth have an unclear relationship with relative neonatal mass in all primates. Relative palatal length (RPL), used as a proxy for midfacial size, is significantly, positively correlated with larger deciduous and permanent postcanine teeth. However, when strepsirrhines alone are examined, larger RPL is correlated with smaller RDV of permanent teeth. In the full sample, RDVs of deciduous premolars are significantly negatively correlated with relative gestation length (RGL), but have no clear relationship with relative weaning age. RDVs of molars lack a clear relationship with RGL; later weaning is associated with larger molar RDV, although correlations are not significant. When strepsirrhines alone are analyzed, clearer trends are present: longer gestations or later weaning are associated with smaller deciduous and larger permanent postcanine teeth (only gestational length correlations are significant). Our results indicate a broad trend that primates with the shortest RGLs precociously develop deciduous teeth; in strepsirrhines, the opposite trend is seen for permanent molars. Anthropoids delay growth of permanent teeth, while strepsirrhines with short RGLs are growing replacement teeth concurrently. A comparison of neonatal volumes with existing information on extent of cusp mineralization indicates that growth of tooth germs and cusp mineralization may be selected for independently. © 2017 Wiley Periodicals, Inc.

Disturbances of dental development distinguish patients with oligodontia-ectodermal dysplasia from isolated oligodontia.

PubMed

Dhamo, B; Kuijpers, M A R; Balk-Leurs, I; Boxum, C; Wolvius, E B; Ongkosuwito, E M

2018-02-01

To investigate phenotypic differences in dental development between isolated oligodontia and oligodontia-ectodermal dysplasia (ED). A total of 129 patients diagnosed with isolated oligodontia and 22 patients with oligodontia as part of ED were eligible. The phenotype of dental development was assessed for the frequency of missing a certain tooth, dental age, development of each tooth present, abnormal size and abnormal shape of teeth. The data were analysed building linear, ordinal and logistic regression models. Compared to patients with isolated oligodontia, patients with oligodontia-ED missed more frequently central incisors and second molars in both jaws, and lateral incisors in the mandible (P < .05). Oligodontia-ED was associated with delayed development of the permanent dentition (β = -0.10; 95% CI: -0.17, -0.03). Specifically, the maxillary teeth: right central incisor, right lateral incisor, right second premolar and left second premolar were delayed approximately from 2 to 4 developmental stages. In addition, the left mandibular second premolar was 3 developmental stages delayed. Abnormal shape of teeth was 7 times more evident in patients with oligodontia-ED compared to patients with isolated oligodontia (OR = 6.54; 95% CI: 2.34, 18.28). The abnormal size of teeth was not a distinctive characteristic for oligodontia-ED. Oligodontia-ED distinguishes from isolated oligodontia by more disturbances in dental development. The abnormal shape of incisors and canines in a patient with oligodontia can raise suspicions for accompanying ectodermal abnormalities. © 2017 The Authors. Orthodontics & Craniofacial Research Published by John Wiley & Sons Ltd.

Revascularization and Apical Plug in an Immature Molar

PubMed Central

Roghanizadeh, Leyla; Fazlyab, Mahta

2018-01-01

Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient’s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development. PMID:29692851

Tooth loss, dementia and neuropathology in the Nun study.

PubMed

Stein, Pamela Sparks; Desrosiers, Mark; Donegan, Sara Jean; Yepes, Juan F; Kryscio, Richard J

2007-10-01

Numerous studies have linked dementia to the subsequent deterioration of oral health. Few investigators, however, have examined oral disease as a potential risk factor in the development of dementia. The authors conducted a study to investigate a potential association between a history of oral disease and the development of dementia. Longitudinal dental records supplemented data collected from 10 annual cognitive assessments of 144 Milwaukee participants in the Nun Study, a longitudinal study of aging and Alzheimer disease, who were 75 to 98 years old. Neuropathologic findings at autopsy were available for 118 participants who died. A low number of teeth increased the risk of higher prevalence and incidence of dementia. Participants with the fewest teeth had the highest risk of prevalence and incidence of dementia. Edentulism or very few (one to nine) teeth may be predictors of dementia late in life.

A long-term study on the clinical effects of mechanical widening of cheek teeth diastemata for treatment of periodontitis in 202 horses (2008-2011).

PubMed

Dixon, P M; Ceen, S; Barnett, T; O'Leary, J M; Parkin, T D; Barakzai, S

2014-01-01

Cheek teeth diastemata are a common cause of painful periodontal disease in horses, but there is limited objective information on their treatment. To assess the long-term response to diastema widening in clinically affected horses. Retrospective study. Medical records from cases of cheek teeth diastemata treated by diastema widening referred to the University of Edinburgh Equine Hospital from 2008 to 2011 were analysed. During this period, 302 horses were diagnosed with clinically significant cheek teeth diastemata, of which 202, median age 11 years, with severe associated periodontitis were treated by widening of 674 problematic diastemata; 89.8% between mandibular cheek teeth and 10.2% between maxillary cheek teeth, with a mean of 1.5 treatments performed per case. These 202 cases showed quidding in 76.2%; weight loss in 33.2%; bitting problems in 20.1% and halitosis in 10.9%, with 5.4% being asymptomatic. Follow-up of 92% of treated cases, a mean of 20.8 months after their initial treatment, showed that 72.6% had complete remission of clinical signs that was permanent (for the duration of this study) in 50.5% and temporary in 22%. A partial response was obtained in 17.2%, no response was obtained in 4.3%, and owners were unsure of response in 5.9%. Clinical improvement was sometimes delayed, with 19% taking >4 weeks following treatment for improvement. Inappropriate sites were burred in individual teeth of 6 horses, causing iatrogenic pulpar exposure in 2 cases, but following treatment none developed clinical signs of apical infection. Diastema widening is an effective but potentially invasive treatment for horses with cheek teeth diastemata with severe periodontitis. Diastema widening by trained personnel is suitable for advanced cases of cheek teeth diastema, but many cases require repeated treatments. © 2013 EVJ Ltd.

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-01-01

Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

The Effect of Systemic Delivery of Aminoguanidine versus Doxycycline on the Resorptive Phase of Alveolar Bone Following modified Widman Flap in Diabetic Rats: A Histopathological and Scanning Electron Microscope (SEM) study.

PubMed

Tella, E; Aldahlawi, S; Eldeeb, A; El Gazaerly, H

2014-07-01

Aminoguanidine (guanylhydrazinehydrochloride) is a drug that prevents many of the classical systemic complications of diabetes including diabetic osteopenia through its inhibitory activity on the accumulation of advanced glycation end -products (AGEs). The aim of the present study was to evaluate the effectiveness of aminoguanidine versus doxycycline in reducing alveolar bone resorption following mucoperiosteal flap in diabetic rats, using the conventional histopathology and scanning electron microscope (SEM). Twenty-seven male albino rats were used in this study. Periodontal defects were induced experimentally on lower anterior teeth. All rats were subjected to induction of diabetes, by IV injection of the pancreatic B-cells toxin alloxan monohydrate. After eight weeks following the establishment of periodontal defects in all rats, the ligation was removed and 3 rats were scarified as negative control (group 1). The remaining animals were divided into three group based on treatment applied following mucoperiosteal flap surgery. Group 2 received saline treatment only, group 3 received doxycycline periostat (1.5 mg/kg/day) for 3 weeks, and group 4 received aminoguanidine (7.3 mmol/kg) for 3 weeks. The fasting glucose level was measured weekly post operatively. After 21 days all rats were sacrificed. Three anterior parts of the mandible of each group was prepared for histopathological examination and two parts were prepared for SEM. Aminoguanidine treated group (group 4) showed statistically significant increased new bone formation, higher number of osteoblasts and decrease osteoclasts number, resorptive lacunae and existing inflammatory cell infiltration as compared to positive control group (group 2) (P<0.05). Doxycycline was also effective in reducing bone loss as documental by histopathological study. The present study showed that aminoguanidine was significantly effective in reducing alveolar bone loss and can modify the detrimental effects of diabetes in alveolar bone resorption.

IMRT delivers lower radiation doses to dental structures than 3DRT in head and neck cancer patients.

PubMed

Fregnani, Eduardo Rodrigues; Parahyba, Cláudia Joffily; Morais-Faria, Karina; Fonseca, Felipe Paiva; Ramos, Pedro Augusto Mendes; de Moraes, Fábio Yone; da Conceição Vasconcelos, Karina Gondim Moutinho; Menegussi, Gisela; Santos-Silva, Alan Roger; Brandão, Thais B

2016-09-07

Radiotherapy (RT) is frequently used in the treatment of head and neck cancer, but different side-effects are frequently reported, including a higher frequency of radiation-related caries, what may be consequence of direct radiation to dental tissue. The intensity-modulated radiotherapy (IMRT) was developed to improve tumor control and decrease patient's morbidity by delivering radiation beams only to tumor shapes and sparing normal tissue. However, teeth are usually not included in IMRT plannings and the real efficacy of IMRT in the dental context has not been addressed. Therefore, the aim of this study is to assess whether IMRT delivers lower radiation doses to dental structures than conformal 3D radiotherapy (3DRT). Radiation dose delivery to dental structures of 80 patients treated for head and neck cancers (oral cavity, tongue, nasopharynx and oropharynx) with IMRT (40 patients) and 3DRT (40 patients) were assessed by individually contouring tooth crowns on patients' treatment plans. Clinicopathological data were retrieved from patients' medical files. The average dose of radiation to teeth delivered by IMRT was significantly lower than with 3DRT (p = 0.007); however, only patients affected by nasopharynx and oral cavity cancers demonstrated significantly lower doses with IMRT (p = 0.012 and p = 0.011, respectively). Molars received more radiation with both 3DRT and IMRT, but the latter delivered significantly lower radiation in this group of teeth (p < 0.001), whereas no significant difference was found for the other dental groups. Maxillary teeth received lower doses than mandibular teeth, but only IMRT delivered significantly lower doses (p = 0.011 and p = 0.003). Ipsilateral teeth received higher doses than contralateral teeth with both techniques and IMRT delivered significantly lower radiation than 3DRT for contralateral dental structures (p < 0.001). IMRT delivered lower radiation doses to teeth than 3DRT, but only for some groups of patients and teeth, suggesting that this decrease was more likely due to the protection of other high risk organs, and was not enough to remove teeth from the zone of high risk for radiogenic disturbance (>30Gy).

A Novel Marker Based Method to Teeth Alignment in MRI

NASA Astrophysics Data System (ADS)

Luukinen, Jean-Marc; Aalto, Daniel; Malinen, Jarmo; Niikuni, Naoko; Saunavaara, Jani; Jääsaari, Päivi; Ojalammi, Antti; Parkkola, Riitta; Soukka, Tero; Happonen, Risto-Pekka

2018-04-01

Magnetic resonance imaging (MRI) can precisely capture the anatomy of the vocal tract. However, the crowns of teeth are not visible in standard MRI scans. In this study, a marker-based teeth alignment method is presented and evaluated. Ten patients undergoing orthognathic surgery were enrolled. Supraglottal airways were imaged preoperatively using structural MRI. MRI visible markers were developed, and they were attached to maxillary teeth and corresponding locations on the dental casts. Repeated measurements of intermarker distances in MRI and in a replica model was compared using linear regression analysis. Dental cast MRI and corresponding caliper measurements did not differ significantly. In contrast, the marker locations in vivo differed somewhat from the dental cast measurements likely due to marker placement inaccuracies. The markers were clearly visible in MRI and allowed for dental models to be aligned to head and neck MRI scans.

Pulp revascularization of immature teeth with apical periodontitis: a clinical study.

PubMed

Ding, Rui Yu; Cheung, Gary Shun-pan; Chen, Jie; Yin, Xing Zhe; Wang, Qian Qian; Zhang, Cheng Fei

2009-05-01

The purpose of this study was to examine the effect of a pulpal revascularization procedure for immature necrotic teeth with apical periodontitis. Twelve patients, each with an immature permanent tooth with chronic or acute apical periodontitis, were recruited. A triantibiotic mix (ciprofloxacin, metronidazole, and minocycline) was used to disinfect the pulp for 1 week. Then a blood clot was created in the canal, over which grey mineral trioxide aggregate was placed. Patients were recalled periodically. Six patients dropped from the study (as a result of pain or failure to induce bleeding after canal disinfection) and instead received a standard apexification procedure. Another 3 patients did not attend any recall appointments. The remaining teeth (n = 3) were found to exhibit complete root development, with a positive response to pulp testing. Revascularization could be effective for managing immature permanent teeth with apical periodontitis with appropriate case selection.

Fused primary first mandibular macromolar with a unique relation to its permanent successors: A rare tooth anomaly.

PubMed

Dhindsa, Abhishek; Garg, Shalini; Damle, S G; Opal, Shireen; Singh, Tavleen

2013-04-01

Dental anomalies of number and forms may occur in the primary and permanent dentition. Various terms have been used to describe dental twinning anomalies: Germination, fusion, concrescence, double teeth, conjoined teeth, twinned teeth, geminifusion, and vicinifusion. Fused tooth is a developmental anomaly that is seen more frequently in the primary than the permanent dentition. Double tooth involving deciduous anterior teeth is found mostly in the mandible. Very few cases of nonsyndromic double primary molar have been reported in the literature. The succeeding permanent tooth is often found missing congenitally in the same region. This article reports a very rare unilateral occurrence of an anomalous, primary mandibular first macromolar formed by fusion with a dysmorphic premolar like supernumerary tooth in deciduous dentition period. Instead of agenesis of succedaneous tooth, the double tooth has been succeeded by normally developing mandibular first premolar in the same region.

[Historical investigation of dentifrice in China].

PubMed

Kubo, M; Song, Q; Tang, F

2001-01-01

A herbal literature survey was carried out on data concerning historical pharmacognostical changes of "dentifrice" in China and how diseases of the teeth and gums had been treated there in ancient times. It had been considered to be a matter of utmost importance that to prevent teeth from decaying, only the brushing of teeth with a toothbrush was necessary. Over time, various tooth agents have been found to treat oral diseases the teeth and gums. Glycyrrhizae Radix, Ginseng Radix, Scutellariae Radix, Menthae Herbal, and salt were widely used materials. Investigations from all approaches are being carried out to develop remedies for oral diseases, including Kampo medicine and the pharmacological effects of numerous crude drugs. When tracing the pharmacognostical changes of dentifrice in ancient China, we felt wonder at and admiration for the abundance of clinical experiences described in the old herbal and medical literature we researched.

Amelogenesis Imperfecta, Facial Esthetics and Snap-On Smile.

PubMed

Wilson, Lee; Bradshaw, Jonathan P; Marks, Murray K

2015-01-01

Amelogenesis imperfecta is a hereditary enamel protein disorder affecting deciduous and secondary crown formation. The prevalence ranges from 1:700 to 1:14,000 depending on the population. These teeth may be hypoplastic, hypomineralized, or hypermineralized and are often discolored, sensitive and caries vulnerable. Patients often present with psychosocial issues due to appearance. Primary teeth are often treated with stainless steel crowns while secondary teeth are treated with full coverage esthetic crowns. The presenting preteen male here was fitted with Snap-On Smile? (www.snaponsmile.com). This treatment option provided cosmetic enhancement of the patient's appearance besides stabilization without altering the primary and secondary dentition during adolescent development.

MicroRNAs as serum biomarkers for periodontitis.

PubMed

Tomofuji, Takaaki; Yoneda, Toshiki; Machida, Tatsuya; Ekuni, Daisuke; Azuma, Tetsuji; Kataoka, Kota; Maruyama, Takayuki; Morita, Manabu

2016-05-01

Studies demonstrated that periodontitis modulates microRNA (miRNAs) expression rates in periodontal tissue. However, the relationship between periodontitis and miRNAs profile in circulation remains unclear. In this study, we investigated the effects of periodontitis on serum miRNAs profile in a rat model. Male Wistar rats (n = 32, 8 weeks old) were divided into four groups of eight rats each. The control groups received no treatment for 2 or 4 weeks. In the other two groups, periodontitis was ligature induced for 2 or 4 weeks. Serum miRNAs expression profiles of each group were compared. Ligation around teeth induced periodontal inflammation at 2 weeks and periodontal tissue destruction at 4 weeks. Microarray results showed that 25 miRNAs were expressed with a <0.5 or >2 difference between the control and periodontitis groups at 4 weeks. Results of real-time PCR revealed that the periodontitis group up-regulated expression rates of serum miR-207 and miR-495 at 2 weeks, and miR-376b-3p at 4 weeks (p < 0.05). Serum miRNAs (miR-207, miR-495, and miR-376b-3p) could be valuable biomarkers for periodontitis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dental complications of rickets in early childhood: case report on 2 young girls.

PubMed

Davit-Béal, Tiphaine; Gabay, Julie; Antoniolli, Pauline; Masle-Farquhar, Jeanne; Wolikow, Maryse

2014-04-01

Vitamin D is an essential hormone for calcium gut absorption. It is also involved in child growth, cancer prevention, immune system responses, and tooth formation. Due to inadequate vitamin D intake and/or decreased sunlight exposure, vitamin D deficiency has resurfaced in developed countries despite known inexpensive and effective preventive methods. Vitamin D deficiency is a common cause of rickets, a condition that affects bone development in children and that can have serious dental complications. Deficiency during pregnancy can cause enamel hypoplasia of primary teeth. Enamel regeneration is currently impossible; hypoplasia is therefore irreversible, and once affected, teeth are prone to fast caries development. Deficiency during early childhood can affect permanent teeth and ensuing caries can sometimes lead to tooth loss at a young age. Oral manifestations of rickets should be diagnosed early by both physicians and dentists to prevent severe dental complications. This case study presents 2 young girls with rickets in early childhood who suffered from subsequent serious tooth decay.

Age Estimation of Infants Through Metric Analysis of Developing Anterior Deciduous Teeth.

PubMed

Viciano, Joan; De Luca, Stefano; Irurita, Javier; Alemán, Inmaculada

2018-01-01

This study provides regression equations for estimation of age of infants from the dimensions of their developing deciduous teeth. The sample comprises 97 individuals of known sex and age (62 boys, 35 girls), aged between 2 days and 1,081 days. The age-estimation equations were obtained for the sexes combined, as well as for each sex separately, thus including "sex" as an independent variable. The values of the correlations and determination coefficients obtained for each regression equation indicate good fits for most of the equations obtained. The "sex" factor was statistically significant when included as an independent variable in seven of the regression equations. However, the "sex" factor provided an advantage for age estimation in only three of the equations, compared to those that did not include "sex" as a factor. These data suggest that the ages of infants can be accurately estimated from measurements of their developing deciduous teeth. © 2017 American Academy of Forensic Sciences.

[Anthropology and oral health projects in developing countries].

PubMed

Grasveld, A E

2016-01-01

The mouth and teeth play an important role in social interactions around the world. The way people deal with their teeth and mouth, however, is determined culturally. When oral healthcare projects are being carried out in developing countries, differing cultural worldviews can cause misunderstandings between oral healthcare providers and their patients. The oral healthcare volunteer often has to try to understand the local assumptions about teeth and oral hygiene first, before he or she can bring about a change of behaviour, increase therapy compliance and make the oral healthcare project sustainable. Anthropology can be helpful in this respect. In 2014, in a pilot project commissioned by the Dutch Dental Care Foundation, in which oral healthcare was provided in combination with anthropological research, an oral healthcare project in Kwale (Kenia) was evaluated. The study identified 6 primary themes that indicate the most important factors influencing the oral health of school children in Kwale. Research into the local culture by oral healthcare providers would appear to be an important prerequisite to meaningful work in developing countries.

Dental histology of Coelophysis bauri and the evolution of tooth attachment tissues in early dinosaurs.

PubMed

Fong, Raymond K M; LeBlanc, Aaron R H; Berman, David S; Reisz, Robert R

2016-07-01

Studies of dinosaur teeth have focused primarily on external crown morphology and thus, use shed or in situ tooth crowns, and are limited to the enamel and dentine dental tissues. As a result, the full suites of periodontal tissues that attach teeth to the jaws remain poorly documented, particularly in early dinosaurs. These tissues are an integral part of the tooth and thus essential to a more complete understanding of dental anatomy, development, and evolution in dinosaurs. To identify the tooth attachment tissues in early dinosaurs, histological thin sections were prepared from the maxilla and dentary of a partial skull of the early theropod Coelophysis bauri from the Upper Triassic (Rhaetian- 209-201 Ma) Whitaker Quarry, New Mexico, USA. As one of the phylogenetically and geologically oldest dinosaurs, it is an ideal candidate for examining dental tissues near the base of the dinosaurian clade. The teeth of C. bauri exhibited a fibrous tooth attachment in which the teeth possessed five tissues: enamel, dentine, cementum, periodontal ligament (PDL), and alveolar bone. Our findings, coupled with those of more recent studies of ornithischian teeth, indicate that a tripartite periodontium, similar to that of crocodilians and mammals, is the plesiomorphic condition for dinosaurs. The occurrence of a tripartite periodontium in dinosaurs adds to the growing consensus that the presence of these tissues is the plesiomorphic condition for the major amniote clades. Furthermore, this study establishes the relative timing of tissue development and growth directions of periodontal tissues and provides the first comparative framework for future studies of dinosaur periodontal development, tooth replacement, and histology. J. Morphol. 277:916-924, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Demineralised human dentine matrix stimulates the expression of VEGF and accelerates the bone repair in tooth sockets of rats.

PubMed

Reis-Filho, Cláudio R; Silva, Elisângela R; Martins, Adalberto B; Pessoa, Fernanda F; Gomes, Paula V N; de Araújo, Mariana S C; Miziara, Melissa N; Alves, José B

2012-05-01

In this study we investigated the possible use of human demineralised dentine matrix (DHDM), obtained from the extracted teeth, as bone graft material and evaluated the expression of vascular endothelial growth factor (VEGF) induced by this material in the healing process of tooth sockets of rats. To evaluate bone regeneration and expression of VEGF induced by DHDM, thirty-two male Wistar rats weighing approximately 200 g were used. After maxillary second molar extraction, the left sockets were filled with DHDM and the right sockets were naturally filled by blood clot (control). The animals were sacrificed at 3, 7, 14 and 21 days after surgery and upper maxillaries were processed for histological, morphometric and immunohistochemical analyses. DHDM was used to evaluate the mechanical effect of bone graft material into sockets. Expression of VEGF was determined by immunohistochemistry in all groups. Our results demonstrated a significant increase in the newly formed bone tissue in sockets of 7, 14 and 21 days and a significant increase in VEGF expression at days 7 and 14 on treated sockets. Our results showed that DHDM increases the expression of VEGF and accelerates the healing process in rats tooth sockets, by stimulating bone deposition and also vessels formation. These results suggest that DHDM has osteoinductive/osteoconductive potential and may represent an efficient grafting material on guided bone regeneration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Growth-Associated Changes in the Periodontal Bone and Molar Teeth of Male Rats

PubMed Central

García, María F; Moreno, Hilda; Rigalli, Alfredo; Puche, Rodolfo C

2009-01-01

Here we report quantitative data associating periodontal bone variables of young conventional rats with the growth process. The hemimandibles of male rats (IIM/Fm stock, 2 to 15 wk of age.) were excised and submitted to conventional morphologic, radiologic, and histologic evaluation. The length, area, or X-ray absorbance of various regions or structures was measured on digital images of radiographs by using an image-analysis program. The sum of periodontal bone areas undergoing resorption (interproximal + intraradicular) increased until 9 or 10 wk of age and decreased thereafter. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The mineral density of resorption areas in alveolar bone fitted sinusoidal kinetics, indicative of the ‘instability’ of the tissue due to its high metabolic activity. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The proportion of root length within alveolar bone exhibited a biphasic curve (minimum at 5 wk of age), due to differences in the growth rates of variables involved in its calculation (distance between the cementoenamel junction to the apex and height of the resorption areas). The distance between the cementoenamel junction and alveolar bone crest over time fitted a sigmoidal function with a point of inflection that did not differ significantly from that of body or mandible dry weight. In summary, the growth process appears to affect periodontal bone support and the distance between the cementoenamel junction and alveolar bone crest in male rats. PMID:19807966

Transforming growth factor-β-induced gene product-h3 inhibits odontoblastic differentiation of dental pulp cells.

PubMed

Serita, Suguru; Tomokiyo, Atsushi; Hasegawa, Daigaku; Hamano, Sayuri; Sugii, Hideki; Yoshida, Shinichiro; Mizumachi, Hiroyuki; Mitarai, Hiromi; Monnouchi, Satoshi; Wada, Naohisa; Maeda, Hidefumi

2017-06-01

The aim of this study was to investigate transforming growth factor-β-induced gene product-h3 (βig-h3) expression in dental pulp tissue and its effects on odontoblastic differentiation of dental pulp cells (DPCs). A rat direct pulp capping model was prepared using perforated rat upper first molars capped with mineral trioxide aggregate cement. Human DPCs (HDPCs) were isolated from extracted teeth. βig-h3 expression in rat dental pulp tissue and HDPCs was assessed by immunostaining. Mineralization of HDPCs was assessed by Alizarin red-S staining. Odontoblast-related gene expression in HDPCs was analyzed by quantitative RT-PCR. Expression of βig-h3 was detected in rat dental pulp tissue, and attenuated by direct pulp capping, while expression of interleukin-1β and tumor necrosis factor-α was increased in exposed pulp tissue. βig-h3 expression was also detected in HDPCs, with reduced expression during odontoblastic differentiation. The above cytokines reduced βig-h3 expression in HDPCs, and promoted their mineralization. Recombinant βig-h3 inhibited the expression of odontoblast-related genes and mineralization of HDPCs, while knockdown of βig-h3 gene expression promoted the expression of odontoblast-related genes in HDPCs. The present findings suggest that βig-h3 in DPCs may be involved in reparative dentin formation and that its expression is likely to negatively regulate this process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring of typodont root movement via crown superimposition of single cone-beam computed tomography and consecutive intraoral scans.

PubMed

Lee, Robert J; Pham, John; Choy, Michael; Weissheimer, Andre; Dougherty, Harry L; Sameshima, Glenn T; Tong, Hongsheng

2014-03-01

The purpose of this study was to develop a new methodology to visualize in 3 dimensions whole teeth, including the roots, at any moment during orthodontic treatment without the need for multiple cone-beam computed tomography (CBCT) scans. An extraoral typodont model was created using extracted teeth placed in a wax base. These teeth were arranged to represent a typical malocclusion. Initial records of the malocclusion, including CBCT and intraoral surface scans, were taken. Threshold segmentation of the CBCT was performed to generate a 3-dimensional virtual model. This model and the intraoral surface scan model were superimposed to generate a complete set of digital composite teeth composed of high-resolution surface scan crowns sutured to the CBCT roots. These composite teeth were individually isolated from their respective arches for single-tooth manipulations. Orthodontic treatment for the malocclusion typodont model was performed, and posttreatment intraoral surface scans before and after bracket removal were taken. A CBCT scan after bracket removal was also obtained. The isolated composite teeth were individually superimposed onto the posttreatment surface scan, creating the expected root position setup. To validate this setup, it was compared with the posttreatment CBCT scan, which showed the true positions of the roots. Color displacement maps were generated to confirm accurate crown superimpositions and to measure the discrepancies between the expected and the true root positions. Color displacement maps through crown superimpositions showed differences between the expected and true root positions of 0.1678 ± 0.3178 mm for the maxillary teeth and 0.1140 ± 0.1587 mm for the mandibular teeth with brackets. Once the brackets were removed, differences of 0.1634 ± 0.3204 mm for the maxillary teeth and 0.0902 ± 0.2505 mm for the mandibular teeth were found. A new reliable approach was demonstrated in an ex-vivo typdont model to have the potential to track the 3-dimensional positions of whole teeth including the roots, with only the initial CBCT scan and consecutive intraoral scans. Since the presence of brackets in the intraoral scan had a minimal influence in the analysis, this method can be applied at any stage of orthodontic treatment. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Precise chronology of differentiation of developing human primary dentition.

PubMed

Hu, Xuefeng; Xu, Shan; Lin, Chensheng; Zhang, Lishan; Chen, YiPing; Zhang, Yanding

2014-02-01

While correlation of developmental stage with embryonic age of the human primary dentition has been well documented, the available information regarding the differentiation timing of the primary teeth was largely based on the observation of initial mineralization and varies significantly. In this study, we aimed to document precise differentiation timing of the developing human primary dentition. We systematically examined the expression of odontogenic differentiation markers along with the formation of mineralized tissue in each developing maxillary and mandibular teeth from human embryos with well-defined embryonic age. We show that, despite that all primary teeth initiate development at the same time, odontogenic differentiation begins in the maxillary incisors at the 15th week and in the mandibular incisors at the 16th week of gestation, followed by the canine, the first primary premolar, and the second primary premolar at a week interval sequentially. Despite that the mandibular primary incisors erupt earlier than the maxillary incisors, this distal to proximal sequential differentiation of the human primary dentition coincides in general with the sequence of tooth eruption. Our results provide an accurate chronology of odontogenic differentiation of the developing human primary dentition, which could be used as reference for future studies of human tooth development.

Development of coronal cementum in hypsodont horse cheek teeth.

PubMed

Sahara, Noriyuki

2014-04-01

The horse is a grazing herbivore whose cheek teeth are hypsodon; that is, they possess long crowns that are completely covered by coronal cement at eruption. For elucidation of the sequential events in the formation of this coronal cementum in the mandibular horse cheek teeth, in the present study the lower 3rd permanent premolar teeth (PM4 ) from 3.5-, 4-, and 5-year-old horses were compared by using radiography, microcomputed tomography (Miro-CT), light microscopy (LM), and scanning electron microscopy (SEM). The present study clearly showed that prior to coronal cementogenesis tartrate-resistant acid phosphatase (TRAP)-positive odontoclasts resorbed on the enamel surface of the reserve crown in horse cheek tooth. Enamel resorption areas were relatively narrow, and started from the cuspal tips, and moved in the apical direction during tooth development. A primary cementum was initially deposited on the irregularly pitted enamel-cementum junction (ECJ) of the infolding and peripheral enamel. The infolding cementum filled grooves completely by the time of tooth eruption. On the other hand, in the peripheral cementum, the secondary and tertiary cementum layers were sequentially deposited on the primary cementum. These two cementum layers were sites for the insertion of the periodontal ligaments, and were continually laid down on the primary cementum coronally rather than apically throughout the life. The results of the present study suggest that the coronal cementum of horse cheek teeth is a multistructural and multifunctional tissue, meeting the requirements of its many different functions. Copyright © 2014 Wiley Periodicals, Inc.

Facial Cosmetic Surgery

MedlinePlus

... find out more. Wisdom Teeth Management Wisdom Teeth Management An impacted wisdom tooth can damage neighboring teeth ... find out more. Wisdom Teeth Management Wisdom Teeth Management An impacted wisdom tooth can damage neighboring teeth ...

Dental Implant Surgery

MedlinePlus

... find out more. Wisdom Teeth Management Wisdom Teeth Management An impacted wisdom tooth can damage neighboring teeth ... find out more. Wisdom Teeth Management Wisdom Teeth Management An impacted wisdom tooth can damage neighboring teeth ...

Your Teeth

MedlinePlus

... Safe Videos for Educators Search English Español Your Teeth KidsHealth / For Kids / Your Teeth What's in this ... help you talk. So let's talk teeth! Tiny Teeth Unlike your heart or brain, your teeth weren' ...

Primary failure of eruption: further characterization of a rare eruption disorder.

PubMed

Frazier-Bowers, Sylvia A; Koehler, Karen E; Ackerman, James L; Proffit, William R

2007-05-01

Posterior open bite has several possible causes, including primary failure of eruption (PFE) that affects all teeth distal to the most mesial involved tooth, mechanical failure of eruption (MFE) (primarily ankylosis) that affects only the involved tooth or teeth, and soft-tissue interferences with eruption (other). Radiographs and other clinical records for 97 cases of failure of posterior eruption submitted for consultation were analyzed to further characterize PFE and distinguish it from MFE. Of the 97 cases, 38 were judged to be clear-cut PFE; 19 were diagnosed as MFE; 32 were classified as indeterminate failure because they were too young to be certain of the distinction between PFE and MFE; and 8 were placed in the "other" category. Two subtypes of PFE were observed. In type 1, eruption failure occurred at or near the same time for all teeth in an affected quadrant. In type 2, a gradient of the time of failure was present, so that some further development of the teeth posterior to the most mesial affected tooth was observed before eruption failure. A family history of eruption problems was noted in 10 of the 38 PFE subjects (26%), and a pedigree analysis was done for 4 families. This was consistent with autosomal dominant transmission. The distinction between PFE and MFE is clinically important because it determines whether all posterior teeth, or only individual affected teeth, will not respond to orthodontic force. Certain diagnosis often requires progress radiographs so that the pattern of eruption of teeth distal to the most mesial affected tooth can be observed.

[Content of fluoride and magnesium in permanent teeth of children and adolescents with constitutional delay of growth and development].

PubMed

Bandura, Marzena; Opalko, Krystyna

2005-01-01

The objective of this study was to determine the content of fluorides and magnesium in permanent teeth of children and adolescents with constitutional delay of growth and development (CDGD) and to correlate the findings with susceptibility to caries. Our study group consisting of 20 patients with CDGD, aged 11 to 20 years, was compared with an age-matched control group of 20 normal subjects. Dentition status was assessed according to the average DMFs score. Acid biopsy of enamel on the labial surface of incisors was done to measure the content of calcium, magnesium, and fluorides. CDGD patients demonstrated a higher average DFs value and less permanent teeth than their normal counterparts. Microanalyses of enamel showed that the depth of the acid biopsy was similar in all subjects. The content of fluorides and magnesium in enamel was lower in patients with CDGD.

Sox2 marks epithelial competence to generate teeth in mammals and reptiles

PubMed Central

Juuri, Emma; Jussila, Maria; Seidel, Kerstin; Holmes, Scott; Wu, Ping; Richman, Joy; Heikinheimo, Kristiina; Chuong, Cheng-Ming; Arnold, Katrin; Hochedlinger, Konrad; Klein, Ophir; Michon, Frederic; Thesleff, Irma

2013-01-01

Tooth renewal is initiated from epithelium associated with existing teeth. The development of new teeth requires dental epithelial cells that have competence for tooth formation, but specific marker genes for these cells have not been identified. Here, we analyzed expression patterns of the transcription factor Sox2 in two different modes of successional tooth formation: tooth replacement and serial addition of primary teeth. We observed specific Sox2 expression in the dental lamina that gives rise to successional teeth in mammals with one round of tooth replacement as well as in reptiles with continuous tooth replacement. Sox2 was also expressed in the dental lamina during serial addition of mammalian molars, and genetic lineage tracing indicated that Sox2+ cells of the first molar give rise to the epithelial cell lineages of the second and third molars. Moreover, conditional deletion of Sox2 resulted in hyperplastic epithelium in the forming posterior molars. Our results indicate that the Sox2+ dental epithelium has competence for successional tooth formation and that Sox2 regulates the progenitor state of dental epithelial cells. The findings imply that the function of Sox2 has been conserved during evolution and that tooth replacement and serial addition of primary teeth represent variations of the same developmental process. The expression patterns of Sox2 support the hypothesis that dormant capacity for continuous tooth renewal exists in mammals. PMID:23462476

Dental anomalies of the deciduous dentition among Indian children: a survey from Jodhpur, Rajasthan, India.

PubMed

Deolia, Shravani Govind; Chhabra, Chaya; Chhabra, Kumar Gaurav; Kalghatgi, Shrivardhan; Khandelwal, Naresh

2015-01-01

Anomalies and enamel hypoplasia of deciduous dentition are routinely encountered by dental professionals and early detection and careful management of such conditions facilitates may help in customary occlusal development. The aim of this study was to determine the prevalence of hypodontia, microdontia, double teeth, and hyperdontia of deciduous teeth among Indian children. The study group comprised 1,398 children (735 boys, 633 girls). The children were examined in department of Pedodontics and Preventive Dentistry in Jodhpur Dental College General Hospital, Jodhpur, Rajasthan, India. Clinical data were collected by single dentist according to Kreiborg criteria, which includes double teeth, hypodontia, microdontia, and supernumerary teeth. Statistical analysis of the data was performed using the descriptive analysis and chi-square test. Dental anomalies were found in 4% of children. The distribution of dental anomalies were significantly more frequent (P = 0.001) in girls (5.8%, n = 38) than in boys (2.7%, n = 18). In relation to anomaly frequencies at different ages, significant difference was found between 2 and 3 years (P = 0.001). Double teeth were the most frequently (2.3%) observed anomaly. The other anomalies followed as 0.3% supernumerary teeth, 0.6% microdontia, 0.6% hypodontia. Identification of dental anomalies at an early age is of great importance as it prevents malocclusions, functional and certain psychological problems.

Biochemical and histopathologic analysis of the effects of periodontitis on left ventricular heart tissues of rats.

PubMed

Köse, O; Arabacı, T; Gedikli, S; Eminoglu, D Ö; Kermen, E; Kızıldağ, A; Kara, A; Ozkanlar, S; Yemenoglu, H

2017-04-01

Current epidemiological works have suggested that chronic infections, such as periodontitis, are associated with an increased risk of cardiovascular diseases, including hypertrophy and heart failure. However, mechanisms behind the association are not known. The aim of this study was to evaluate the effects of periodontitis on the serum lipid levels, inflammatory marker levels and left ventricular heart muscle tissues of rats. Eighteen male Sprague-Dawley rats were randomly divided into two groups: control (without ligature) and experimental periodontitis (EP; ligatured). Periodontitis was induced by placing ligatures (3.0 silk) at a submarginal position of the lower first molar teeth for 5 wk. Serum samples were collected for biochemical studies (C-reactive protein, interleukin-1β, tumor necrosis factor-α and serum lipids), after which the rats were killed and heart tissue samples were obtained for histopathological and immunological studies (nuclear factor kappa B and β-myosin heavy chain). Significant increases in C-reactive protein and interleukin-1β levels and no statistically significant increase in tumor necrosis factor-α level were observed in the EP group compared to the control group. In addition, total cholesterol, low-density lipoprotein cholesterol and triglyceride levels were significantly higher in the EP group. Stereological and immunological findings showed that the number of nuclear factor kappa B-p65- and β-myosin heavy chain-positive cardiomyocytes increased significantly in the left ventricular tissue samples of the rats with periodontitis. Early chronic phase effects of periodontitis on heart tissue are in the form of degenerative and hypotrophic changes. Prolonging the exposure to systemic inflammatory stress may increase the risk of occurrence of hypertrophic changes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Morphometric analysis of developing crowns of maxillary primary second molars and permanent first molars in humans.

PubMed

Peretz, B; Nevis, N; Smith, P

1998-07-01

The purpose of this study was firstly to characterize the changes occurring in size and form of the mineralizing maxillary second primary molar and first permanent molar crowns, and secondly to determine if similar changes in size and form characterize enamel apposition in the crowns of these teeth. Twenty-five primary second molars and 20 maxillary permanent first molars at various stages of development, found in archaeological excavations in Israel, were examined for a number of measured variables using image analyser software. Teeth were divided into two groups according to their stage of development: stage I included all teeth at an early stage of development in which mesiobuccal-cusp height was less than 5 mm for the primary molar and 5.9 mm for the permanent molar; stage 2 included all teeth in later stages of development where mesiobuccal-cusp height was greater than these values. In the primary molar, a significant increase was found between the two stages in almost all variables. Significant correlations were also found between all intercusp distances and the external variables. Strong correlations between height of the mesiobuccal cusp and all external and internal variables were noted in stage 1, but fewer in stage 2. In the permanent tooth, no increase was observed in intercusp distances and very few correlations were found between and among the variables. The results suggest that a change in the shape of the maxillary primary second molar occurs during formation, with the lingual cusp tips moving lingually and distally, and the distobuccal cusp tips moving distally. No change occurs in the shape of the maxillary permanent first molar during crown formation. Growth of the maxillary primary second and permanent first molar crowns occurs in 'bursts' of development.

Alveolar process fractures in the permanent dentition. Part 2. The risk of healing complications in teeth involved in an alveolar process fracture.

PubMed

Lauridsen, Eva; Gerds, Thomas; Andreasen, Jens Ove

2016-04-01

To analyze the risk of pulp canal obliteration (PCO), pulp necrosis (PN), repair-related resorption (RRR), infection-related resorption (IRR), ankylosis-related resorption (ARR), marginal bone loss (MBL), and tooth loss (TL) for teeth involved in an alveolar process fracture and to identify possible risk factors. A total of 91 patients with 223 traumatized teeth. The risks of PCO, PN, RRR, IRR, ARR, MBL, and TL were analyzed separately for teeth with immature and mature root development using Kaplan-Meier and Aalen-Johansen methods. Possible risk factors for PN (age, fracture in relation to apex, displacement, gingival injury, degree of repositioning, type of splint, duration of splinting, treatment delay, and antibiotics) were analyzed for mature teeth using Cox regression. The level of significance was 5%. Immature: No severe complications (PN, IRR, ARR, MBL, or TL) were diagnosed during follow up. Mature: Estimated risk after a 10-year follow up: PN: 56% (95% confidence interval (CI): 48.1-63.9), IRR: 2.5% (95% CI: 0-5.1), ARR: 2.1% (95% CI: 0.1-4.1), MBL: 2.4% (95% CI: 0.3-4.4), and TL: 7.8% (95% CI: 0-15.7). The following factors significantly increased the risk of PN in teeth with mature root development: fracture in relation to apex (hazard ratio (HR): 2.6 (95% CI: 0.2 - 5.7), P = 0.01), displacement in the horizontal part of the fracture >2 mm (HR: 1.8; 95% CI: 1.1-3.2, P = 0.03), incomplete repositioning (HR: 2.1 (95% CI: 1.3-3.5), P = 0.003), and age >30 years (HR: 2.3 (95% CI: 1.1-4.6), P = 0.02). The type of splint (rigid or flexible), the duration of splinting (more or less than 4 weeks), and the administration of antibiotics did not affect the risk of PN. Teeth involved in alveolar process fractures appear, apart from PN, to have a good prognosis. A conservative treatment approach is recommended. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Microleakage of different temporary filling materials in primary teeth.

PubMed

Odabas, Mesut Enes; Tulunoglu, Ozlem; Ozalp, Serife Ozdemir; Bodur, Haluk

2009-01-01

The aim of this study was to compare the sealing properties of IRM, Coltosol, Cavit G, Adhesor and Clip, which used as temporary filling material in coronal access openings in extracted human primary teeth. Standardized access cavities of 2 x 2 mm were prepared in the eighty-four, caries-free human primary anterior teeth. The teeth were divided randomly into five groups of 16 teeth each. Temporary restorative materials Group A: IRM (Dentsply), Group B: Coltosol (Coltone), Group C: Cavit G (3M), Group D: Adhesor (Spofa Dental) and Group E: Clip (Voco) were applied according to the manufacturer's directions. The specimens were immersed silver nitrate and placed in film developer under fluorescent for 24 hours. The sectioned specimens were evaluated under a digital microscope at x 20 magnifications and blindly scored for microleakage. Clip presented the least microleakage value whereas; Adhesor and IRM presented the higher microleakage values. There were statistically significant differences between Clip and the others groups, while there were no statistically significant differences in microleakage between IRM, Adhesor, Coltosol and Cavit G. However the leakage scores of Clip and Cavit G were congruent (p = 0.454). Amongst the five materials, Clip exhibited a better sealing ability.

Dental Pulp Revascularization of Necrotic Permanent Teeth with Immature Apices.

PubMed

El Ashiry, Eman A; Farsi, Najat M; Abuzeid, Sawsan T; El Ashiry, Mohamed M; Bahammam, Hammam A

The treatment of immature necrotic teeth with apical periodontitis presents challenges in endodontic and pediatric dentistry. Revascularization is a recent treatment for such cases as an alternative to conventional apexification. The purpose is to examine the effect of a pulpal revascularization procedure on immature necrotic teeth with apical periodontitis. Twenty patients were enrolled for pulp revascularization procedure by root canal disinfection using a triple antibiotic mixture for 1-2 weeks, followed by creating a blood clot, sealing the root canal orifice using white mineral trioxide aggregate and a coronal seal of composite resin. Patients were recalled periodically for up to 24 months. During follow-up, all patients were asymptomatic. Three cases of chronic apical periodontitis showed clinical disappearance of the sinus tract 2 weeks after treatment. Radiography revealed progressive periapical radiolucency resolution within the first 12 months. Within 12-24 months, the treated teeth showed progressive increases in dentinal wall thickness, root length and continued root development. Clinical and radiographic evidence showed successful revascularization treatments of immature necrotic permanent teeth with apical periodontitis. More studies are necessary to understand the underlying mechanisms and to perform histopathology of the pulp space contents after revascularization procedures.

Regenerative Endodontic Treatment versus Apical Plug in Immature Teeth: Three-Year Follow-Up.

PubMed

Asgary, Saeed; Fazlyab, Mahta; Nosrat, Ali

This report compares and evaluates the treatment outcomes of regenerative endodontic treatment and apical plug as two accepted treatment protocols in a pair of necrotic immature maxillary central incisors of a 12-year old female. The patient was referred complaining of a dull pain and swelling in her upper lip area. She had a history of trauma to the anterior maxilla two years earlier. Both teeth were clinically diagnosed with pulp necrosis and periapical radiographs revealed that separate periapical radiolucent lesions surrounded the immature apices of both teeth. The left and right incisors were treated with apical plug and regenerative endodontic treatment, respectively, using calcium-enriched mixture (CEM) cement. The patient was followed-up for three years. During this period, both teeth were clinically asymptomatic and showed complete radiographic healing of the periapical lesions. The right central incisor showed root development. No tooth discoloration was evident. Apexification by apical plug placement and pulp regeneration are both reliable treatments for immature non-vital teeth. In order to choose the right treatment the advantages of either technique should be weighed against its drawbacks. CEM cement can be successfully applied for both purposes. This biomaterial causes less discoloration of the tooth.

Attitude and beliefs of traditional birth attendants to prematurely erupted teeth of infants in urban local government areas in Ibadan, Nigeria.

PubMed

Bankole, Olubunmi; Taiwo, Juliana; Nasiru, Olukemi

Traditional birth attendants (TBAs) can be invaluable in assisting to dispel myths commonly associated with natal/neonatal teeth. To ensure correct delivery of the message, baseline data of their beliefs is important. To assess the attitude and beliefs of some Nigerian TBAs to prematurely erupted teeth in infants, a total enumeration of the TBAs in the five urban Local Government Areas in Ibadan was conducted and 163 consenting TBAs were recruited using an interviewer-administered questionnaire. The attitude of the TBAs was that of fear and shock (35.6%) while 30 (18.4%) will consider the child weird. Perceived causes of the variation include evil spirits (31.9%), contravening cultural taboos (9.2%), and prolonged gestation (4.9%). Beliefs on the effect of natal/neonatal teeth on the child include strange behavior (31.3%), child developing evil spiritual powers (41.1%), and mental retardation (3.1%). Practices included advising parents to get rid of/or hide the child (4.9%) and immediate extraction of the teeth with/without sacrifices (35.6%). There is an urgent need to address knowledge gaps by giving health education to TBAs.

Distalization of Maxillary First Permanent Molar by Pendulum Appliance in Mixed Dentition Period

PubMed Central

Shetty, Prakashchandra; Anandakrishna, Latha; Rawat, Anuradha

2017-01-01

Introduction Mesial drifting of molar teeth in maxillary arch is corrected by movement of the molars distally. In addition to traditional distal movement techniques, such as extraoral force application and removable appliances, various intra-arch devices have been introduced since 1980s. These intra-arch appliances have nearly eliminated the need for patient cooperation. Case report The purpose of this paper is to report a case of 10-year-old male patient with loss of space in maxillary molar teeth treated by intra-arch appliance-pendulum appliance by distalization of maxillary first permanent molar teeth. Distaliza-tion of the permanent molar teeth helped in proper eruption of second premolar teeth without any extensive treatment procedures. Conclusion In the present case report, the treatment of developing malocclusion was corrected by utilizing the concept of interceptive orthodontics. Hence, correction of space loss in mixed dentition period using pendulum appliance can eliminate the fixed orthodontic therapy. How to cite this article Paranna S, Shetty P, Anandakrishna L, Rawat A. Distalization of Maxillary First Permanent Molar by Pendulum Appliance in Mixed Dentition Period. Int J Clin Pediatr Dent 2017;10(3):299-301. PMID:29104393

Demystifying the Mysteries: Sexual Dimorphism in Primary Teeth

PubMed Central

Bhatia, Hind Pal; Sood, Shveta; Sharma, Naresh

2017-01-01

Introduction One of the critical steps in the process of identification is the sex determination of an unknown individual. Many studies have shown that sex can be determined using the human skeleton, especially by examining the pelvis and skull. Odontometric analysis of the human sexual variation has been less investigated, especially of primary dentition. Aim To verify the presence of sexual dimorphism in primary teeth of local population of Faridabad, Haryana, India. Materials and Methods The research was performed on dental casts of 500 children (250 boys and 250 girls, age range 3-5 years). Mesiodistal and buccolingual crown dimensions of maxillary and mandibular primary teeth were measured with a digital Vernier’s caliper and were analysed for sexual dimorphism. Mann-Whitney-U test was used to check the statistical significance of difference in tooth dimensions among boys and girls. Results Differences were found in the mean values of mesiodistal and buccolingual diameters of primary teeth, in which boys generally had larger crown diameters than girls. Conclusion Primary teeth may be used as an additional tool for sex identification of juvenile skeletons where other dimorphic features are not much developed. PMID:28571276

Comparison of age estimation between 15-25 years using a modified form of Demirjian’s ten stage method and two teeth regression formula

NASA Astrophysics Data System (ADS)

Amiroh; Priaminiarti, M.; Syahraini, S. I.

2017-08-01

Age estimation of individuals, both dead and living, is important for victim identification and legal certainty. The Demirjian method uses the third molar for age estimation of individuals above 15 years old. The aim is to compare age estimation between 15-25 years using two Demirjian methods. Development stage of third molars in panoramic radiographs of 50 male and female samples were assessed by two observers using Demirjian’s ten stages and two teeth regression formula. Reliability was calculated using Cohen’s kappa coefficient and the significance of the observations was obtained from Wilcoxon tests. Deviations of age estimation were calculated using various methods. The deviation of age estimation with the two teeth regression formula was ±1.090 years; with ten stages, it was ±1.191 years. The deviation of age estimation using the two teeth regression formula was less than with the ten stages method. The age estimations using the two teeth regression formula or the ten stages method are significantly different until the age of 25, but they can be applied up to the age of 22.

Autogenous transplantation of teeth with complete root formation: two case reports.

PubMed

Teixeira, C S; Pasternak, B; Vansan, L P; Sousa-Neto, M D

2006-12-01

Autotransplantation is an alternative treatment for replacing lost teeth when suitable donor teeth are available. This paper presents two cases of successful autogenous tooth transplantation. Two third molars with complete root development were autogenously transplanted from their original sockets into new recipient sites on the same side of the mouth, one in the maxilla and one in the mandible. In both cases, the third molars were transplanted immediately after the first molar extractions. To provide better adaptation of the donor teeth, the recipient alveolar sites were remodelled using surgical burs. Semi-rigid splints were maintained for 45 and 15 days, respectively. Root canal treatment commenced one a week after transplantation and the canals were medicated with a calcium hydroxide paste before they were filled. Clinical and radiographic findings after 5 and 3 years of follow-up, respectively, are discussed in relation to the literature. Autogenous transplantation of teeth with complete root formation may be considered as a viable treatment option to conventional prosthetic and implant rehabilitation for both therapeutic and economic reasons. Careful surgical and endodontic procedure, together with careful case selection may lead to satisfactory aesthetic and functional outcomes.

Reevaluation of Physaloptera bispiculata (Nematoda: Spiruroidaea) by light and scanning electron microscopy.

PubMed

Mafra, A C; Lanfredi, R M

1998-06-01

This study was undertaken to clarify several aspects of morphological and taxonomic characters of Physaloptera bispiculata Vaz and Pereira, 1935, a parasite of the water rat, Nectomys squamipes. The cephalic structures (including lips, papillae, teeth, amphids, and porous areas) and details of the posterior end of male and female adult worms were examined by scanning electron microscopy, leading to the addition of new taxonomic characters for this species. We consider P. bispiculata a valid species, based on a comparative analysis of the specific characters for P. bispiculata and P. getula Seurat, 1917, including the morphology and morphometry of body structures as well as number and disposition of caudal papillae of the males.

Expression of insulin-like growth factor-1 and proliferating cell nuclear antigen in human pulp cells of teeth with complete and incomplete root development.

PubMed

Caviedes-Bucheli, J; Canales-Sánchez, P; Castrillón-Sarria, N; Jovel-Garcia, J; Alvarez-Vásquez, J; Rivero, C; Azuero-Holguín, M M; Diaz, E; Munoz, H R

2009-08-01

To quantify the expression of insulin-like growth factor-1 (IGF-1) and proliferating cell nuclear antigen (PCNA) in human pulp cells of teeth with complete or incomplete root development, to support the specific role of IGF-1 in cell proliferation during tooth development and pulp reparative processes. Twenty six pulp samples were obtained from freshly extracted human third molars, equally divided in two groups according to root development stage (complete or incomplete root development). All samples were processed and immunostained to determine the expression of IGF-1 and PCNA in pulp cells. Sections were observed with a light microscope at 80x and morphometric analyses were performed to calculate the area of PCNA and IGF-1 immunostaining using digital image software. Mann-Whitney's test was used to determine statistically significant differences between groups (P < 0.05) for each peptide and the co-expression of both. Expression of IGF-1 and PCNA was observed in all human pulp samples with a statistically significant higher expression in cells of pulps having complete root development (P = 0.0009). Insulin-like growth factor-1 and PCNA are expressed in human pulp cells, with a significant greater expression in pulp cells of teeth having complete root development.

Bilateral mandibular paramolars.

PubMed

Dhull, Kanika Singh; Dhull, Rachita Singh; Panda, Swagatika; Acharya, Sonu; Yadav, Shweta; Mohanty, Gatha

2014-01-01

Supernumerary tooth is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. They can cause a variety of complications in the develo-ping dentition. Supernumerary teeth can present in various forms and in any region of the mandible or maxilla, but have a predisposition for the anterior maxilla. Here is the presentation of a case of unusual location of supernumerary teeth located in between mandibular first and second molar region bilaterally. How to cite this article: Dhull KS, Dhull RS, Panda S, Acharya S, Yadav S, Mohanty G. Bilateral Mandibular Paramolars. Int J Clin Pediatr Dent 2014;7(1):40-42.

Dose to the Developing Dentition During Therapeutic Irradiation: Organ at Risk Determination and Clinical Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, Reid F., E-mail: Reid.Thompson@uphs.upenn.edu; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania; Schneider, Ralf A., E-mail: ralf.schneider@psi.ch

Purpose: Irradiation of pediatric facial structures can cause severe impairment of permanent teeth later in life. We therefore focused on primary and permanent teeth as organs at risk, investigating the ability to identify individual teeth in children and infants and to correlate dose distributions with subsequent dental toxicity. Methods and Materials: We retrospectively reviewed 14 pediatric patients who received a maximum dose >20 Gy(relative biological effectiveness, RBE) to 1 or more primary or permanent teeth between 2003 and 2009. The patients (aged 1-16 years) received spot-scanning proton therapy with 46 to 66 Gy(RBE) in 23 to 33 daily fractions formore » a variety of tumors, including rhabdomyosarcoma (n=10), sarcoma (n=2), teratoma (n=1), and carcinoma (n=1). Individual teeth were contoured on axial slices from planning computed tomography (CT) scans. Dose-volume histogram data were retrospectively obtained from total calculated delivered treatments. Dental follow-up information was obtained from external care providers. Results: All primary teeth and permanent incisors, canines, premolars, and first and second molars were identifiable on CT scans in all patients as early as 1 year of age. Dose-volume histogram analysis showed wide dose variability, with a median 37 Gy(RBE) per tooth dose range across all individuals, and a median 50 Gy(RBE) intraindividual dose range across all teeth. Dental follow-up revealed absence of significant toxicity in 7 of 10 patients but severe localized toxicity in teeth receiving >20 Gy(RBE) among 3 patients who were all treated at <4 years of age. Conclusions: CT-based assessment of dose distribution to individual teeth is feasible, although delayed calcification may complicate tooth identification in the youngest patients. Patterns of dental dose exposure vary markedly within and among patients, corresponding to rapid dose falloff with protons. Severe localized dental toxicity was observed in a few patients receiving the largest doses of radiation at the youngest ages; however, multiple factors including concurrent chemotherapy confounded the dose-effect relationship. Further studies with larger cohorts and appropriate controls will be required.« less

The detection of periapical pathoses using digital periapical radiography and cone beam computed tomography in endodontically retreated teeth - part 2: a 1 year post-treatment follow-up.

PubMed

Davies, A; Patel, S; Foschi, F; Andiappan, M; Mitchell, P J; Mannocci, F

2016-07-01

Part 2 of this prospective clinical study aimed to compare the 1-year outcome of root canal retreatments, when individual roots and teeth were assessed by periapical radiographs and cone beam computed tomography (CBCT). Subjects participating in this study had been referred for management of an endodontic problem associated with one or more root filled teeth. Root canal retreatment was performed by Specialists or postgraduate students under the direct supervision of Specialist endodontic staff. A total of 98 teeth (84 patients) were reassessed clinically and radiographically 1 year after completion of root canal retreatment. The postoperative periapical radiographs and CBCT scans were compared with their respective pre-treatment (diagnostic) periapical radiographs and CBCT scans. The increase or decrease in size of existing periapical radiolucencies and development of new radiolucencies were assessed by a consensus panel consisting of two calibrated examiners. They also determined an appropriate management plan for each case based on the radiographical findings. Comparison of the outcome diagnosis of individual roots and teeth and case management, when assessed by periapical radiographs and CBCT scans, was performed using chi-squared and McNemar's tests. An overall favourable result of 93% success for teeth (96% roots) was recorded when the assessment was undertaken by periapicals compared with 77% success for teeth (87% roots) when assessed by CBCT. A significant difference in outcome diagnosis of single paired roots (P < 0.0001) and teeth (P = 0.0001) was observed when comparing periapicals to CBCT for the cohort of teeth as a whole. When comparing the future management plan on the basis of radiographic information alone, there was a significant difference between periapicals and CBCT-based management (P = 0.01). Diagnosis using CBCT revealed a significantly lower number of favourable outcomes than periapicals in root canal retreatment. This significantly affected the future management of cases attending for a review. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A comparison of the erosive potential of different beverages in primary and permanent teeth using an in vitro model.

PubMed

Lussi, A; Kohler, N; Zero, D; Schaffner, M; Megert, B

2000-04-01

The aim of this study was to compare the erosive potential of different beverages and foodstuffs in primary and permanent teeth. Sixty primary and 60 permanent human teeth were immersed for 3 min in the solution under study (5 teeth per treatment group). Surface microhardness was measured before and after exposure. Initial (baseline) surface microhardness was lower for primary teeth than for permanent teeth. In both primary and permanent teeth, Sprite showed the highest decrease in surface microhardness, whereas yogurt showed an increase in surface microhardness in the primary teeth. Overall decrease was 27.2 +/- 17.5 KHN (mean +/- SD) for primary and 25.9 +/- 15.6 KHN for permanent teeth. The comparison of the erosive susceptibility in this in vitro model showed that primary teeth were not more susceptible to erosion compared to permanent teeth.

Molecular differences between mature and immature dental pulp cells: Bioinformatics and preliminary results.

PubMed

Chen, Long; Jiang, Yifeng; Du, Zhen

2018-04-01

Although previous studies have demonstrated that dental pulp stem cells (DPSCs) from mature and immature teeth exhibit potential for multi-directional differentiation, the molecular and biological difference between the DPSCs from mature and immature permanent teeth has not been fully investigated. In the present study, 500 differentially expressed genes from dental pulp cells (DPCs) in mature and immature permanent teeth were obtained from the Gene Expression Omnibus online database. Based on bioinformatics analysis using the Database for Annotation, Visualization and Integrated Discovery, these genes were divided into a number of subgroups associated with immunity, inflammation and cell signaling. The results of the present study suggest that immune features, response to infection and cell signaling may be different in DPCs from mature and immature permanent teeth; furthermore, DPCs from immature permanent teeth may be more suitable for use in tissue engineering or stem cell therapy. The Online Mendelian Inheritance in Man database stated that Sonic Hedgehog (SHH), a differentially expressed gene in DPCs from mature and immature permanent teeth, serves a crucial role in the development of craniofacial tissues, including teeth, which further confirmed that SHH may cause DPCs from mature and immature permanent teeth to exhibit different biological characteristics. The Search Tool for the Retrieval of Interacting Genes/Proteins database revealed that SHH has functional protein associations with a number of other proteins, including Glioma-associated oncogene (GLI)1, GLI2, growth arrest-specific protein 1, bone morphogenetic protein (BMP)2 and BMP4, in mice and humans. It was also demonstrated that SHH may interact with other genes to regulate the biological characteristics of DPCs. The results of the present study may provide a useful reference basis for selecting suitable DPSCs and molecules for the treatment of these cells to optimize features for tissue engineering or stem cell therapy. Quantitative polymerase chain reaction should be performed to confirm the differential expression of these genes prior to the beginning of a functional study.

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

PubMed

Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

2016-01-01

Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In conjunction with the presence of resorption pits and the evidence for pseudothecodont tooth implantation, the tooth eruption and implantation characters described in the present study either place mosasaurs among the varanoids or suggest convergent evolution mechanisms between both clades, with mosasaurs evolving somewhat independently from a common varanoid ancestor.

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

PubMed Central

Liu, Min; Reed, David A.; Cecchini, Giancarlo M.; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S.; Monahan, Richard; Luan, Xianghong

2016-01-01

Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In conjunction with the presence of resorption pits and the evidence for pseudothecodont tooth implantation, the tooth eruption and implantation characters described in the present study either place mosasaurs among the varanoids or suggest convergent evolution mechanisms between both clades, with mosasaurs evolving somewhat independently from a common varanoid ancestor. PMID:27242535

Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.

PubMed

Ekizer, Abdullah; Uysal, Tancan; Güray, Enis; Akkuş, Derya

2015-02-01

The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm(2) over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 ± 0.36 mm) was significantly higher than the second time period (0.24 ± 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.

Schwann Cell Phenotype Changes in Aging Human Dental Pulp.

PubMed

Couve, E; Lovera, M; Suzuki, K; Schmachtenberg, O

2018-03-01

Schwann cells are glial cells that support axonal development, maintenance, defense, and regeneration in the peripheral nervous system. There is limited knowledge regarding the organization, plasticity, and aging of Schwann cells within the dental pulp in adult permanent teeth. The present study sought to relate changes in the pattern of Schwann cell phenotypes between young and old adult teeth with neuronal, immune, and vascular components of the dental pulp. Schwann cells are shown to form a prominent glial network at the dentin-pulp interface, consisting of nonmyelinating and myelinating phenotypes, forming a multicellular neuroimmune interface in association with nerve fibers and dendritic cells. Schwann cell phenotypes are recognized by the expression of S100, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), Sox10, GAP43, and p75NTR markers. In young adult teeth, a dense population of nonmyelinating Schwann cells projects processes in close association with sensory nerve terminals through the odontoblast layer, reaching the adjacent predentin/dentin domain. While GAP43 and p75NTR are highly expressed in nonmyelinating Schwann cells from young adult teeth, the presence of these markers declines significantly in old adult teeth. Myelinated axons, identified by MBP expression, are mainly present at the Raschkow plexus and within nerve bundles in the dental pulp, but their density is significantly reduced in old adult versus young adult teeth. These data reveal age-related changes within the glial network of the dental pulp, in association with a reduction of coronal dental pulp innervation in old adult versus young adult teeth. The prominence of Schwann cells as a cellular component at the dentin-pulp interface supports the notion that their association with sensory nerve terminals and immune system components forms part of an integrated multicellular barrier for defense against pathogens and dentin repair.

Spectrophotometric determination of irrigant extrusion using passive ultrasonic irrigation, EndoActivator, or syringe irrigation.

PubMed

Rodríguez-Figueroa, Carolina; McClanahan, Scott B; Bowles, Walter R

2014-10-01

Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation. One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples. Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1-3 μL) in straight roots or curved roots occurred in 10%-11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3-10 μL of NaOCl. The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The Effect of Different Chemical Surface Treatments of Denture Teeth on Shear Bond Strength: A Comparative Study

PubMed Central

Palekar, Umesh; Awinashe, Vaibav; Mishra, Sunil Kumar; Kawadkar, Abhishek; Rahangdale, Tripti

2014-01-01

Background: The development of better cross linked acrylic resin teeth has solved the problems related to wearing and discoloration of acrylic teeth. The same cross linking at ridge lap region acts as a double edge sword as it weakens the bond between denture base and tooth. Aim of Study: The purpose of study was to evaluate the effect of surface treatment on the bond strength of resin teeth to denture base resin using monomethyl methacrylate monomer and dichloromethane with no surface treatment acting as control. Settings and Design:Denture base cylinder samples in wax (n=180) were made with maxillary central incisor attached at 450 (JIST 6506). These samples were randomly and equally divided into three groups of 60 each. These specimens were then flasked, dewaxed as per the standard protocol. Materials and Methods: Before acrylization, ridge lap area was treated as follows: Group A- no surface treatment act as control, Group B treated with monomethyl methacrylate monomer, Group C treated with dichloromethane. Digitally controlled acryliser was used for acrylization as per manufacturer’s instructions and shear bond strength was tested on Universal Testing Machine (Servo Hydraulic, 50kN High Strain, BISS Research). Statistical Analysis used: Result was statistically analyzed with One-way analysis of variance (ANOVA) and Post-hoc ANOVA Tukey’s HSD test at 5% level of significance. Results: The application of dichloromethane showed increased bond strength between cross linked acrylic resin teeth and heat cure denture base resin followed by monomethyl methacrylate monomer and control group. Conclusion: The application of dichloromethane on the ridge lap surface of the resin teeth before packing of the dough into the mold significantly increased the bond strength between cross linked acrylic resin teeth and heat cure denture base resin. PMID:25121057

Tooth replantation after use of Euro-Collins solution or bovine milk as storage medium: a histomorphometric analysis in dogs.

PubMed

Sottovia, André Dotto; Sottovia Filho, Dagoberto; Poi, Wilson Roberto; Panzarini, Sônia Regina; Luize, Danielle Shima; Sonoda, Celso Koogi

2010-01-01

Euro-Collins solution was developed for the preservation of organs for transplantation, whose characteristics have raised interest for its use as a storage medium for avulsed teeth before replantation. This study evaluated histologically and morphometrically the healing process of dog teeth replanted after storage in Euro-Collins solution or bovine milk. Eighty roots of 4 young adult mongrel dogs were randomly assigned to 4 groups (n = 20) and the root canals were instrumented and obturated with gutta-percha and a calcium hydroxide-based sealer. After 2 weeks, the teeth were extracted and subjected to the following protocols: GI (negative control), replantation immediately after extraction; GII (positive control), bench-drying for 2 hours before replantation; GIII and GIV, immersion in 10 mL of whole bovine milk and Euro-Collins solution at 4 degrees C, respectively, for 8 hours before replantation. The animals were sacrificed 90 days postoperatively. The pieces containing the replanted teeth were subjected to routine processing for histologic and histometric analyses under light microscopy and polarized light microscopy. Root resorption was observed in all groups. GII exhibited the greatest loss of dental structure (P < .01), and inflammatory resorption was predominant in this group. Storage in milk showed poorer results than immediate replantation and storage in Euro-Collins solution (P < .01). The teeth stored in Euro-Collins solution presented similar extension of root resorption and periodontal ligament reorganization to those of immediately replanted teeth. The findings of this study suggest that the Euro-Collins solution is an adequate storage medium for keeping avulsed teeth for up to 8 hours before replantation.

Dentinogenic responses after direct pulp capping of miniature swine teeth with Biodentine.

PubMed

Tziafa, Christina; Koliniotou-Koumpia, Eugenia; Papadimitriou, Serafim; Tziafas, Dimitrios

2014-12-01

The aim of this study was to evaluate pulpal responses after experimental direct pulp capping of mechanically exposed teeth with a new calcium silicate-based dentin replacement material. Thirty-four anterior and posterior teeth of 3 miniature swine were used. Class V or I cavities were prepared on the buccal or occlusal surfaces, respectively. Pulpal exposures were further performed using a round carbide bur 0.8 mm in diameter. Exposures were treated with white MTA Angelus (Angelus, Londrina, PR, Brazil) or Biodentine (Septodont, Saint Maur des Fosses, France), and the cavities were further restored with Biodentine. The pulpal tissue responses were histologically assessed at postoperative periods of 3 and 8 weeks. Data were statistically analyzed using the Kruskal Wallis and the Mann-Whitney U tests. Inflammatory infiltration or pulp tissue necrosis was not found in any of the specimens. All teeth showed mineralized matrix formation in the form of a complete hard tissue bridge composed of osteodentin or osteodentin followed by a discontinuous or continuous reparative dentin zone. A significantly higher thickness of the hard tissue bridge was found in the group of teeth treated with Biodentine at both 3 and 8 weeks. A number of teeth, which were under root development at the onset of the experimental procedures, exhibited ectopic pulp calcification. The application of both calcium silicate-based materials in direct contact with the mechanically exposed pulp of healthy miniature swine teeth led to pulp repair with complete hard tissue bridge formation. The thickness of hard tissue bridges was significantly higher after pulp capping with Biodentine. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A cluster randomised trial of effectiveness of educational intervention in primary health care on early childhood caries.

PubMed

Mohebbi, S Z; Virtanen, J I; Vahid-Golpayegani, M; Vehkalahti, M M

2009-01-01

Early childhood caries (ECC) remains a serious problem in several developing and developed countries. This cluster randomised trial evaluated the impact of a 6-month educational intervention on ECC. The trial targeted 12- to 15-month-old children (n = 242) and their mothers in Tehran, Iran, visiting 18 public health centres, randomly selected and assigned to two intervention groups and one control group. At baseline, each mother was interviewed and each child underwent a dental examination of all teeth for the number of decayed teeth (dt) and of upper central incisors for the number of teeth with enamel caries (de). All mothers in the two intervention groups (A and B) received oral health instructions from the vaccination staff. In addition, group A received extra reminders. The outcome was defined as increments in the number of teeth with dt or de, as percentages of children developing new dt or de, and as the number needed to treat (NNT). No new de appeared in group A, the mean de increment in group B was 0.2 (SD = 0.6), and in the controls, it was 0.4 (SD = 0.7) (p < 0.05). The percentages of children developing new de were 0, 14, and 26%, respectively. No differences in dt increments were found. Regarding de, NNT for group A was 4 and for B 9; the figures for dt were 13 and 17, respectively. In conclusion, oral health education given to mothers by general health staff is a valuable tool to prevent caries in infants and toddlers. 2009 S. Karger AG, Basel.

Vascularization of the gray whale palate (Cetacea, Mysticeti, Eschrichtius robustus): soft tissue evidence for an alveolar source of blood to baleen.

PubMed

Ekdale, Eric G; Deméré, Thomas A; Berta, Annalisa

2015-04-01

The origin of baleen in mysticetes heralded a major transition during cetacean evolution. Extant mysticetes are edentulous in adulthood, but rudimentary teeth develop in utero within open maxillary and mandibular alveolar grooves. The teeth are resorbed prenatally and the alveolar grooves close as baleen germ develops. Arteries supplying blood to highly vascularized epithelial tissue from which baleen develops pass through lateral nutrient foramina in the area of the embryonic alveolar grooves and rudimentary teeth. Those vessels are hypothesized to be branches of the superior alveolar artery, but branches of the greater palatine arteries may play a role in the baleen vascularization. Through a combination of latex injection, CT, and traditional dissection of the palate of a neonatal gray whale (Eschrichtius robustus), we confirm that the baleen receives blood from vessels within the superior alveolar canal via the lateral foramina. The greater palatine artery is restricted to its own passage with no connections to the baleen. This study has implications for the presence of baleen in extinct taxa by identifying the vessels and bony canals that supply blood to the epithelium from which baleen develops. The results indicate that the lateral foramina in edentulous mysticete fossils are bony correlates for the presence of baleen, and the results can be used to help identify bony canals and foramina that have been used to reconstruct baleen in extinct mysticetes that retained teeth in adulthood. Further comparisons are made with mammals that also possess oral keratin structures, including ruminants, ornithorhynchid monotremes, and sirenians. © 2015 Wiley Periodicals, Inc.

The effect of anchovy substrate application to fluor retention rate on Sprague Dawley rat tooth email (in vivo)

NASA Astrophysics Data System (ADS)

Zabrina, S.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Usage of anchovies (Stolephorus insularis), which contain a high fluoride concentration in a CaF2 compound, needs to be examined as a topical fluoridative agent. Aim: To study the effects of an anchovy substrate application, either by chewing or smearing, in increasing fluoride retention of enamel. Fourteen Sprague Dawley rats were divided into five groups: baseline, experimental (feeding and smearing), and negative controls. After 15 days, lower incisor teeth were extracted and fluoride retention on the enamel surface was measured using EDX. Data were analyzed by the independent samples t-test, the Mann-Whitney U test, and the Kruskal-Wallis test. There was a significant increase in fluoride retention on enamel from the experimental groups compared to the negative control group (p < 0.05). Fluoride retention levels of the experimental feeding group (6.823%) were slightly higher than those of the experimental smearing group (6.783%), though the difference was not statistically significant (p < 0.05). Anchovy substrate application, either by chewing or smearing, increases fluoride retention on tooth enamel.

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes, João Eduardo; Briso, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents. PMID:27008262

Ten Thousand Years of Environment Assessment Using Synchrotron Radiation Micro Beam

NASA Astrophysics Data System (ADS)

Shirasawa, K.; Ide-Ektessabi, A.; Koizumi, A.; Azechi, M.

2003-08-01

The environment surrounding human has changed through civilization and industrialization, and through these developments, problems including the pollution from heavy metals such as lead and mercury have arisen. In this study, we analyzed major and trace elements in modern and prehistoric teeth by x-ray fluorescence (XRF) analysis using synchrotron radiation micro beam, in order to assess the changes of the environment through the civilization and the industrialization and their affects to the human. It is suggested that teeth accumulate elements in the mineral phase, hydroxiapatite, during their formation, and because there are no significant turnovers, teeth are concerned to be indicators of the environment of the donor. We first analyzed the elements on the surface of tooth from modern individual and tooth from human remains of Jomon period to assess the heavy metal concentration and effect of the diagenesis. The adhering ground elements on the prehistoric teeth showed high amount of Ti, Fe, Mn and other metallic elements.

The history of Latin teeth names.

PubMed

Šimon, František

2015-01-01

This paper aims to give an account of the Latin naming of the different types of teeth by reviewing relevant historical and contemporary literature. The paper presents etymologies of Latin or Greek teeth names, their development, variants and synonyms, and sometimes the names of their authors. The Greek names did not have the status of official terms, but the Latin terms for particular types of teeth gradually established themselves. Names for the incisors, canines and molars are Latin calques for the Greek ones (tomeis, kynodontes, mylai), dens serotinus is an indirect calque of the Greek name (odús) opsigonos, and the term pre-molar is created in the way which is now common in modern anatomical terminology, using the prefix prae- = pre and the adjective molaris. The Latin terms dentes canini and dentes molares occur in the Classical Latin literature, the term (dentes) incisivi is found first time in medieval literature, and the terms dentes premolares and dens serotinus are modern-age ones.

A Simple and Efficient Method of Extracting DNA from Aged Bones and Teeth.

PubMed

Liu, Qiqi; Liu, Liyan; Zhang, Minli; Zhang, Qingzhen; Wang, Qiong; Ding, Xiaoran; Shao, Liting; Zhou, Zhe; Wang, Shengqi

2018-05-01

DNA is often difficult to extract from old bones and teeth due to low levels of DNA and high levels of degradation. This study established a simple yet efficient method for extracting DNA from 20 aged bones and teeth (approximately 60 years old). Based on the concentration and STR typing results, the new method of DNA extraction (OM) developed in this study was compared with the PrepFiler™ BTA Forensic DNA Extraction Kit (BM). The total amount of DNA extracted using the OM method was not significantly different from that extracted using the commercial kit (p > 0.05). However, the number of STR loci detected was significantly higher in the samples processed using the OM method than using the BM method (p < 0.05). This study aimed to establish a DNA extraction method for aged bones and teeth to improve the detection rate of STR typing and reduce costs compared to the BM technique. © 2017 American Academy of Forensic Sciences.

Concept and development of a computerized positioning of prosthetic teeth for complete dentures.

PubMed

Busch, M; Kordass, B

2006-04-01

To date, CAD/CAM technology has made no noteworthy inroads into removable dentures. We want to present a new area of application for this in our study. Models of the maxilla and edentulous mandible were 3D scanned. The software detects and automatically reconstructs the reference structures that are anatomically important for the set-up of artificial teeth, such as the alveolar ridge centerlines and the interalveolar relations between the alveolar ridges. In a further step, the occlusal plane is semiautomatically defined and the front dental arch is designed. After these design features have been determined, artificial teeth are selected from a database and set up automatically. The dental technician can assess the esthetics and function of the suggested dental set-up on the computer screen and make slight corrections if necessary. Summarizing: The interplay of hardware and software components within on integrated solution including conversion of the "virtual" into a real positioning of prosthetic teeth is presented.

Isolation and evaluation of dental pulp stem cells from teeth with advanced periodontal disease.

PubMed

Derakhshani, Ali; Raoof, Maryam; Dabiri, Shahriar; Farsinejad, Ali Reza; Gorjestani, Hedayat; Yaghoobi, Mohammad Mehdi; Shokouhinejad, Noushin; Ehsani, Maryam

2015-04-01

Successful isolation of mesenchymal stem cells from waste tissues might be extremely promising for developing stem cell-based therapies. This study aimed to explore whether cells retrieved from teeth extracted due to advanced periodontal disease present mesenchymal stem cell-like properties. Pulp cells were isolated from 15 intact molars and 15 teeth with advanced periodontal disease. Cell proliferation and markers of mesenchymal stem cells were evaluated. Based on the RT-PCR and agarose gel electrophoresis, nucleostemin, Oct-4 and jmj2c, but not Nanog, were expressed in undifferentiated mesenchymal stem cells of both groups. Interestingly, diseased pulp exhibited higher gene expressions although it was not statistically significant. The average percentage of BrdU positive cells in the diseased group (84.4%, n = 5) was significantly higher than that of the control group (65.4%, n = 5) (t-test, P = 0.001). Our results indicate the successful isolation of mesenchymal stem cells from the pulp tissue of hopeless periodontally involved teeth.

[MODERN INSTRUMENTS FOR EAR, NOSE AND THROAT RENDERING AND EVALUATION IN RESEARCHES ON RUSSIAN SEGMENT OF THE INTERNATIONAL SPACE STATION].

PubMed

Popova, I I; Orlov, O I; Matsnev, E I; Revyakin, Yu G

2016-01-01

The paper reports the results of testing some diagnostic video systems enabling digital rendering of TNT teeth and jaws. The authors substantiate the criteria of choosing and integration of imaging systems in future on Russian segment of the International space station kit LOR developed for examination and download of high-quality images of cosmonauts' TNT, parodentium and teeth.

Long-term follow up of revascularization using platelet-rich fibrin.

PubMed

Ray, Herbert L; Marcelino, Janel; Braga, Raquel; Horwat, Richard; Lisien, Michael; Khaliq, Shahryar

2016-02-01

Trauma is one of the primary causes of tooth loss and pulpal injury in adolescents and children. Prior to regenerative endodontics, treatment of necrotic, immature teeth with open apices was limited to long-term calcium hydroxide (Ca(OH)2 ) apexification and subsequent root canal therapy or extraction. Through revascularization, retention of these teeth can be achieved and the elimination of patient symptoms and the radiographic appearance of continued root development were obtained. This report illustrates a revascularization protocol through a case where platelet-rich fibrin (PRF) was utilized as an autologous scaffold for traumatized, necrotic, immature teeth with incomplete root development. Through consistent follow-up reports, comprising of both clinical examination and radiographs, marked improvement in the condition of the traumatized tooth was noted. This case demonstrates the feasibility of utilizing PRF as an effective treatment protocol for traumatized teeth in lieu of traditional treatment protocols, such as long-term calcium hydroxide (Ca(OH)2 ) apexification or extraction. The choice of utilizing PRF, as opposed to other platelet concentrates, such as platelet-rich plasma (PRP) or a blood clot, lies in PRF's ability to allow for a slow, long-term release of autologous growth factors. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Bony outgrowths on the jaws of an extinct sperm whale support macroraptorial feeding in several stem physeteroids

NASA Astrophysics Data System (ADS)

Lambert, Olivier; Bianucci, Giovanni; Beatty, Brian L.

2014-06-01

Several extinct sperm whales (stem Physeteroidea) were recently proposed to differ markedly in their feeding ecology from the suction-feeding modern sperm whales Kogia and Physeter. Based on cranial, mandibular, and dental morphology, these Miocene forms were tentatively identified as macroraptorial feeders, able to consume proportionally large prey using their massive teeth and robust jaws. However, until now, no corroborating evidence for the use of teeth during predation was available. We report on a new specimen of the stem physeteroid Acrophyseter, from the late middle to early late Miocene of Peru, displaying unusual bony outgrowths along some of the upper alveoli. Considering their position and outer shape, these are identified as buccal maxillary exostoses. More developed along posterior teeth and in tight contact with the high portion of the dental root outside the bony alveoli, the exostoses are hypothesized to have developed during powerful bites; they may have worked as buttresses, strengthening the teeth when facing intense occlusal forces. These buccal exostoses further support a raptorial feeding technique for Acrophyseter and, indirectly, for other extinct sperm whales with a similar oral apparatus ( Brygmophyseter, Livyatan, Zygophyseter). With a wide size range, these Miocene stem physeteroids were major marine macropredators, occupying ecological niches nowadays mostly taken by killer whales.

Modeling and Tool Wear in Routing of CFRP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iliescu, D.; Fernandez, A.; Gutierrez-Orrantia, M. E.

2011-01-17

This paper presents the prediction and evaluation of feed force in routing of carbon composite material. In order to extend tool life and improve quality of the machined surface, a better understanding of uncoated and coated tool behaviors is required. This work describes (1) the optimization of the geometry of multiple teeth tools minimizing the tool wear and the feed force, (2) the optimization of tool coating and (3) the development of a phenomenological model between the feed force, the routing parameters and the tool wear. The experimental results indicate that the feed rate, the cutting speed and the toolmore » wear are the most significant factors affecting the feed force. In the case of multiple teeth tools, a particular geometry with 14 teeth right helix right cut and 11 teeth left helix right cut gives the best results. A thick AlTiN coating or a diamond coating can dramatically improve the tool life while minimizing the axial force, roughness and delamination. A wear model has then been developed based on an abrasive behavior of the tool. The model links the feed rate to the tool geometry parameters (tool diameter), to the process parameters (feed rate, cutting speed and depth of cut) and to the wear. The model presented has been verified by experimental tests.« less

Dental magnetic resonance imaging: making the invisible visible.

PubMed

Idiyatullin, Djaudat; Corum, Curt; Moeller, Steen; Prasad, Hari S; Garwood, Michael; Nixdorf, Donald R

2011-06-01

Clinical dentistry is in need of noninvasive and accurate diagnostic methods to better evaluate dental pathosis. The purpose of this work was to assess the feasibility of a recently developed magnetic resonance imaging (MRI) technique, called SWeep Imaging with Fourier Transform (SWIFT), to visualize dental tissues. Three in vitro teeth, representing a limited range of clinical conditions of interest, imaged using a 9.4T system with scanning times ranging from 100 seconds to 25 minutes. In vivo imaging of a subject was performed using a 4T system with a 10-minute scanning time. SWIFT images were compared with traditional two-dimensional radiographs, three-dimensional cone-beam computed tomography (CBCT) scanning, gradient-echo MRI technique, and histological sections. A resolution of 100 μm was obtained from in vitro teeth. SWIFT also identified the presence and extent of dental caries and fine structures of the teeth, including cracks and accessory canals, which are not visible with existing clinical radiography techniques. Intraoral positioning of the radiofrequency coil produced initial images of multiple adjacent teeth at a resolution of 400 μm. SWIFT MRI offers simultaneous three-dimensional hard- and soft-tissue imaging of teeth without the use of ionizing radiation. Furthermore, it has the potential to image minute dental structures within clinically relevant scanning times. This technology has implications for endodontists because it offers a potential method to longitudinally evaluate teeth where pulp and root structures have been regenerated. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effective of diode laser on teeth enamel in the teeth whitening treatment

NASA Astrophysics Data System (ADS)

Klunboot, U.; Arayathanitkul, K.; Chitaree, R.; Emarat, N.

2011-12-01

This research purpose is to investigate the changing of teeth color and to study the surface of teeth after treatment by laser diode at different power densities for tooth whitening treatment. In the experiment, human-extracted teeth samples were divided into 7 groups of 6 teeth each. After that laser diode was irradiated to teeth, which were coated by 38% concentration of hydrogen peroxide, during for 20, 30 and 60 seconds at power densities of 10.9 and 52.1 W/cm2. The results of teeth color change were described by the CIEL*a*b* systems and the damage of teeth surface were investigated by scanning electron microscopy (SEM). The results showed that the power density of the laser diode could affect the whiteness of teeth. The high power density caused more luminous teeth than the low power density did, but on the other hand the high power density also caused damage to the teeth surface. Therefore, the laser diode at the low power densities has high efficiency for tooth whitening treatment and it has a potential for other clinical applications.

Comparative Evaluation of Impact Strength of Fragment Bonded Teeth and Intact Teeth: An In Vitro Study

PubMed Central

Venugopal, L; Lakshmi, M Narasimha; Babu, Devatha Ashok; Kiran, V Ravi

2014-01-01

Background: To test and compare the impact strength of fragment bonded teeth with that of intact teeth by using impact testing machine (pendulum type) as a mode of load. Materials and Methods: Forty extracted, maxillary, central incisors selected for this study (20 control group and 20 experimental group). In experimental group, teeth crowns were fractured with a microtome at 2.5 mm from mesioincisal angle cervically, fractured portion is attached to original crown portion with 3 M single bond dentin bonding agent and 3 M Z ‘100’, composite resin. Impact strength of fragment bonded teeth and intact teeth tested with impact testing machine and compared. Results: Mean impact strength of fragment bonded teeth (30.76 KJ/M2 ) is not statistically significant deferent from mean impact strength of intact teeth (31.11 KJ/M2 ). Conclusion: Mean impact strength of fragment bonded teeth is not statistically different with that of intact teeth. Hence, after fracture of teeth if it is restored with fragment reattachment by using 3 M single bond dentin bonding agent and 3 M Z ‘100’ composite resin is having impact strength like that of intact teeth. How to cite the article: Venugopal L, Lakshmi MN, Babu DA, Kiran VR. Comparative evaluation of impact strength of fragment bonded teeth and intact teeth: An in vitro study. J Int Oral Health 2014;6(3):73-6. PMID:25083037

Double talon cusps on supernumerary tooth fused to maxillary central incisor: Review of literature and report of case

PubMed Central

2014-01-01

Human tooth development is a continuous process begin at the sixth weeks in utero and extends to about sixth months after birth for the primary dentition and from sixteenth week in utero to late adolescence for permanent dentition. There is no other organ of the human body which takes so long to attain its ultimate morphology as dentition. Several physiologic growth processes participate in the progressive development of the teeth including: initiation, proliferation, histodifferentiation, morphodifferentiation, apposition, calcification, and eruption. Aberrations in different stages of tooth development can result in unique manifestations both in primary and permanent dentitions. The fact that premaxilla is the predilection site for the occurrence of supernumerary teeth, talon cusp, dens invaginatus, and geminated teeth may suggest that the embryological development of premaxilla differ from other sites of the jaws. The dental abnormalities presented in this review are of great concern to dentist and parents because they create clinical, pathological and esthetic problems. Dental practitioner should be aware of the clinical sign, associated problems and treatment options for a given case. Key words:Double talon cusps, fusion, supernumerary, case report. PMID:25593664

Development of dental charts according to tooth development and eruption for Turkish children and young adults

PubMed Central

Afşin, Hüseyin; Ozaslan, Abdi; Karadayı, Şükriye

2014-01-01

Purpose In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. Materials and Methods In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Results Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. Conclusion The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults. PMID:24944959

Pulpal responses to cavity preparation in aged rat molars.

PubMed

Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

2006-10-01

The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals.

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model.

PubMed

Hikida, Takuji; Yamaguchi, Masaru; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-07-01

Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR.

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model

PubMed Central

Hikida, Takuji; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-01-01

Objective Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Methods Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. Results On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. Conclusions These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR. PMID:27478800

Teething

MedlinePlus

Eruption of primary teeth; Well child care - teething ... 6 and 8 months old. All 20 baby teeth should be in place by the time a ... months old. Some children do not show any teeth until much later than 8 months, but this ...

A dental vision system for accurate 3D tooth modeling.

PubMed

Zhang, Li; Alemzadeh, K

2006-01-01

This paper describes an active vision system based reverse engineering approach to extract the three-dimensional (3D) geometric information from dental teeth and transfer this information into Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM) systems to improve the accuracy of 3D teeth models and at the same time improve the quality of the construction units to help patient care. The vision system involves the development of a dental vision rig, edge detection, boundary tracing and fast & accurate 3D modeling from a sequence of sliced silhouettes of physical models. The rig is designed using engineering design methods such as a concept selection matrix and weighted objectives evaluation chart. Reconstruction results and accuracy evaluation are presented on digitizing different teeth models.

Revascularization for a necrotic immature permanent lateral incisor: a case report and literature review.

PubMed

Kottoor, Jojo; Velmurugan, Natanasabapathy

2013-07-01

Revascularization is a valuable treatment in immature necrotic teeth that allows the continuation of root development. This article describes the successful revascularization treatment of an immature maxillary lateral incisor that was initially diagnosed with apical periodontitis. The tooth was asymptomatic and functional clinically and radiographically during the follow-up period of 5 years. The follow-up showed evidence of progressive thickening of the dentinal walls, development of root length and apical closure. The article also discusses the currently available literature regarding revascularization of immature permanent teeth. © 2012 John Wiley & Sons Ltd, BSPD and IAPD.

Pharyngeal teeth of the freshwater drum (Aplodinotus grunniens) a predator of the zebra mussel (Dreissena polymorpha)

USGS Publications Warehouse

French, John R. P.

1997-01-01

The morphology of pharyngeal teeth of freshwater drum (Aplodinotus grunniens) was studied to determine changes that occur during growth of drum that may relate to consumption of zebra mussel (Dreissena polymorpha) by larger fish. Pharyngeal teeth were of three types. Cardiform teeth were replaced by villiform teeth, which were replaced by molariform teeth as the size class of drum increased. Molariform teeth comprised over 85% of total surface area of dentition in fish 265 mm long.

Effect of fluoride on growth and acid production by Streptococcus mutans in dental plaque.

PubMed Central

van der Hoeven, J S; Franken, H C

1984-01-01

The aim of this study was to measure the effect of fluoride on the production of organic acids by Streptococcus mutans in dental plaque. The effect was studied in a simplified model of dental plaque with gnotobiotic rats monoinfected with S. mutans Ny341. Adaptation of S. mutans to fluoride was induced by feeding one group of the rats on fluoride-containing diet and drinking water. No difference was found in the accumulation of S. mutans on the teeth between the fluoride-adapted and the control groups. However, there was a significant difference in the amount of lactic acid in metabolically resting plaque between the groups, lactic acid being lower in the fluoride-adapted plaque. At 5 min after a rinse containing 10% sucrose, a high level of lactic acid was found in plaque from animals not exposed to fluoride. Rinses containing 4 or 20 mM fluoride before the sucrose rinse significantly inhibited the lactic acid production in the control group. In the plaque from rats on fluoridated diet and drinking water the sucrose-induced production of lactic acid was not inhibited by a 4 mM fluoride rinse. Moreover, the production of lactic acid in the fluoride-adapted plaque was prolonged. The results indicate that due to fluoride adaptation the inhibition of acid production is unlikely to be important for the caries-preventive action of fluoride. PMID:6746094

Effects of green tea and bisphosphonate association on dental socket repair of rats.

PubMed

Mada, Edson Yoshihiro; Santos, Alana Claro Cunha; Fonseca, Angelica Cristina; Biguetti, Claudia Cristina; Neves, Fernando Tozze Alves; Saraiva, Patrícia Pinto; Matsumoto, Mariza Akemi

2017-03-01

To evaluate the effects of green tea intake and zoledronic acid intravenous therapy on teeth socket repair. Sixty male albinus Wistar rats were divided into 4 groups: C-Control, intravenous (IV) 0.9% saline solution (SS), GT-1% green tea in drinking water and IV SS, BP-IV zoledronic acid (BP), and BP+GT-IV BP and 1% green tea. 0.035mg/kg of BP was administered every two weeks. After ten weeks, right upper molars were extracted and the green tea started to be offered for GT and BP+GT. After 7, 14, and 28days the animals were euthanized. Histopathology analysis revealed lack of socket repair in BP and BP+GT groups, which presented significant increased number of polimorphonuclear leukocytes at day 28, in comparison with C (p<0.05). No significant differences were detected between C and the experimental groups at the same period (p<0.05) when considering mononuclear leukocytes. Immunolabeling revealed that the association of BP and GT caused a slight disturbance in OPG/RANKL system and retarded Runx-2 labeling. Although strong TRAP labeling was observed, most of the positive cells in BP and BP+GT groups were not located on bone surface. Socket healing of rats treated with BP and regular drinking green tea presented no relevant differences in comparison to those treated with BP alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nanosilver coated orthodontic brackets: in vivo antibacterial properties and ion release.

PubMed

Metin-Gürsoy, Gamze; Taner, Lale; Akca, Gülçin

2017-02-01

Silver nanoparticles are currently utilized in the fields of dentistry. The aim of this study was to evaluate the antibacterial properties and ion release of nanosilver coated orthodontic brackets compared to conventional brackets. Nanosilver coating process was applied to standard orthodontic brackets placed on the mandibular incisors of Wistar Albino rats in the study group and conventional brackets in the control group. Dental plaque, mucosal vestibular smears, saliva, and blood samples were collected from rats at various days. The amounts of nanosilver ions in blood and saliva were measured and microbiological evaluation was made for Streptococcus mutans. For testing cariogenicity, all rats were sacrificed at the end of 75 days under anaesthesia. Teeth were stained using a caries indicator, then the caries ratio was assessed. Nanosilver coated orthodontic bracket favoured the inhibition of S.mutans on Day 30 and reduction of caries on the smooth surfaces. The nanosilver amounts in the saliva and serum samples were significantly higher in the study group on Day 7. It is suggested that nanosilver coated orthodontic brackets, as an antibacterial agent without patient compliance, could be helpful for the prevention of white spot lesions during fixed orthodontic treatment. © The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Effect of Low-Intensity Pulsed Ultrasound on a Rat Model of Dentin-Dental Pulp Injury and Repair.

PubMed

Wang, Fei; Li, Yueheng; Yang, Zhengyan; Lu, Keke; Zuo, Jing; Zhou, Zhi

2017-01-01

This study investigated histopathologic changes in dental pulp after treatment with low-intensity pulsed ultrasound (LIPUS). Fifty rats were randomly divided into an experimental group (n = 25) and a blank control group (n = 25). In the experimental group, a cavity was prepared in the bilateral maxillary first molars. The upper right first molars were stimulated with LIPUS (30 mW/cm 2 , 1.5 MHz) for 20 min/d. The cavities prepared in the left teeth were used as experimental controls (i.e., no LIPUS). Five rats in each group were sacrificed at days 1, 3, 5, 7 and 14. Inflammatory response was visible at different time points after cavity preparation, peaking at day 3, after which it gradually weakened. More reparative dentin was found on the LIPUS treatment side. transforming growth factor-β1 expression increased after treatment, peaking at day 5 and returning to normal at day 14 on both sides, but was stronger with LIPUS treatment. SMAD2 and SMAD3 expressions in the dental pulp gradually increased after cavity preparation, especially in the experimental group. LIPUS promoted the repair of dentin-pulp complex injury, to a certain extent and should be investigated further as a potential therapy. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Gear Crack Propagation Path Studies: Guidelines for Ultra-Safe Design

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2001-01-01

Design guidelines have been established to prevent catastrophic rim fracture failure modes when considering gear tooth bending fatigue. Analysis was performed using the finite element method with principles of linear elastic fracture mechanics. Crack propagation paths were predicted for a variety of gear tooth and rim configurations. The effects of rim and web thicknesses, initial crack locations, and gear tooth geometry factors such as diametral pitch, number of teeth, pitch radius, and tooth pressure angle were considered. Design maps of tooth/rim fracture modes including effects of gear geometry, applied load, crack size, and material properties were developed. The occurrence of rim fractures significantly increased as the backup ratio (rim thickness divided by tooth height) decreased. The occurrence of rim fractures also increased as the initial crack location was moved down the root of the tooth. Increased rim and web compliance increased the occurrence of rim fractures. For gears with constant pitch radii, coarser-pitch teeth increased the occurrence of tooth fractures over rim fractures. Also, 25 deg pressure angle teeth had an increased occurrence of tooth fractures over rim fractures when compared to 20 deg pressure angle teeth. For gears with constant number of teeth or gears with constant diametral pitch, varying size had little or no effect on crack propagation paths.

Effect of CO2, Nd:YAG, and Er:YAG lasers on dentin and pulp tissues in dogs

NASA Astrophysics Data System (ADS)

Abt, Elliot; Wigdor, Harvey A.; Walsh, Joseph T., Jr.; Brown, Joseph D.

1992-06-01

Although there has been interest in lasers in dentistry since lasers were first developed in the early 1960's, this interest was limited until recently. Over the past five years there has been a flurry of interest to find the most effective wavelength and parameters of treatment. With this interest has come clinical and experimental reports. This project is a pilot study to investigate laser effects on dogs teeth. Multiple teeth from 2 dogs (n equals 40) were treated using either a CO2, Nd:YAG, or an Er:YAG laser, or slow-speed rotary instrumentation. One dog died after treatment and was not used in this study. The second dog was sacrificed four days after treatment with the lasers and the teeth were decalcified and processed for light microscopy. The dentin and pulpal tissues were then evaluated for changes from their normal histologic patterns. The purpose of this study was to first determine if the dog would be a good model for in-vivo histologic testing of lasers and second to evaluate the histologic effects of different lasers on dog's teeth. Our findings suggest that each laser causes a different degree of effect to the treated teeth. The specifics of these effects are discussed herein.

Effects of hydrogen peroxide on the light reflectance and morphology of bovine enamel.

PubMed

Kwon, Y H; Huo, M S; Kim, K H; Kim, S K; Kim, Y J

2002-05-01

The purpose of this study was to examine the effects of a bleaching agent (30% hydrogen peroxide) on the surface of bovine enamel using a scanning electron microscope and a UV-VIS-NIR spectrophotometer. Five non-carious bovine incisors were bleached for 0, 1, 2 and 3 days using 30% hydrogen peroxide. The light reflectance spectrum was measured using a spectrophotometer with diffuse reflectance mode. Colour values and colour differences in the teeth were evaluated from the reflectance measurements with the CIE L*a*b* colour coordinate system. Surface alterations in the bleached and unbleached teeth were studied using a scanning electron microscope. The change of reflectance in the teeth was related to the change of colour. Most reflectance change occurred within a 1-day bleaching, and this result was confirmed by a CIE L*a*b* colour coordinate system. The colour differences in the bleached teeth were significant enough to be perceived by the observer's eye. The comparison of bleached to unbleached bovine enamel revealed that the bleached surface showed non-uniform slight morphological alterations, and it developed varying degrees of surface porosity. This study indicates that the bleached bovine teeth showed apparent colour differences as well as slight morphological alterations after bleaching.

[PARENT’S AND CHILDREN’S BEHAVIOR AND KNOWLEDGE ABOUT ORAL HEALTH].

PubMed

Beljan, M; Puharić, Z; Žulec, M; Borić, D; Neumuller, K Radičanin

2016-09-01

Responsible health behavior plays an important role in every individual. Oral health quality results from the level of information available, attitudes, habits and nutrition. Family is the most important environment where children can acquire knowledge, attitudes and habits related to oral health. The aim of the study was to compare the habits of parents and children related to their oral health, and to conclude how parental behavior influences oral health of their children. The study included 101 parent-child pairs (age 11-15 years), their knowledge and behavior according to their oral hygiene, fluoro-prophylaxis and nutrition assessed by anonymous questionnaire. Oral health of parents was estimated according to their tooth loss and compensation, while oral health of children was assessed by dental examination. A total of 101 child-parent pairs were included. Most children were excellent pupils (43.56%). In the group of parents, most participants were mothers (73.27%). Most parents had high school education (65.35%) and were employed (61.62%), and most perceived themselves to be living with average financial situation (86%). A comparable proportion of parents (95%) and children (87%) believed that it was necessary to wash teeth at least twice a day (p=0.125) and most of them thought it necessary to brush teeth for 1-3 minutes (57% of children and 57.43% of parents; p=0.599). The majority of children (56%) and parents (72%) considered it necessary to use dental floss with a toothbrush and toothpaste (p=0.065), while 63% of children and 71.72% of parents believed that toothpaste contained fluoride (p=0.156). Most of the parents (72.3%) and children (65.35%) brushed teeth in the morning and at bedtime (p=0.167) for 1-3 minutes (p=0.098). About 30% of parents and children used the handler for brushing teeth (p=1). Most children (86.32%) and parents (92.1%) had 3-5 meals a day (p=0.181), and 80% of them had their teeth examined by a dentist the year before (p=0.658). The children believing that teeth should be brushed only in the morning have a 3.38-fold greater chance to develop tooth disorders (DMFT >0; p=0.004). Those that do not know that caries and periodontal diseases can be prevented have a 26.3-fold greater chance to develop caries compared to those who are aware of it. Children of parents who only brush their teeth in the morning have a 25 times higher chance of developing CEP >0 as compared with those that brush their teeth after each meal (p=0.016). Children of parents who give them money to buy snacks are 2.9 times more likely to develop CEP >0 (p=0.01) compared to children without money for snack. Children of parents who feel that their health is not good have 3.9 times higher chance of developing CEP >0 as compared to those whose parents think they have a neat bite (p=0.017). Oral hygiene in Croatia is still not at a level of the standards in Western countries. Ignorance about oral hygiene and irresponsible health behavior are the main causes of the poor condition of the teeth. Results of this study showed the close relationship between family attitudes about oral hygiene, as children follow their parents’ habits and behavior. In conclusion, by educating parents, we influence their children’s behavior and knowledge about oral health, and this is the way that health workers should plan interventions to prevent oral diseases.

Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes).

PubMed

Underwood, Charlie J; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J; Fraser, Gareth J; Smith, Moya Meredith

2015-01-01

Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the general plesiomorphic vertebrate dental condition.

Biodynamics of attachments used in overdentures: experimental analysis with photoelasticity.

PubMed

Labaig, C; Marco, R; Fons, A; Selva, E J

1997-03-01

Treatment with overdentures is an alternative to conventional complete prostheses. Different types of attachments can be placed in natural teeth that act as retainers for overdentures. The photoelastic relationship between the design of the attachment and the distribution of occlusal forces among the abutment teeth and the distal alveolar ridges was examined. The results were used to develop a classification for clinical cases so that the correct attachment design can be selected.

Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

PubMed

Thevissen, P W; Galiti, D; Willems, G

2012-11-01

In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

Developmental and evolutionary novelty in the serrated teeth of theropod dinosaurs.

PubMed

Brink, K S; Reisz, R R; LeBlanc, A R H; Chang, R S; Lee, Y C; Chiang, C C; Huang, T; Evans, D C

2015-07-28

Tooth morphology and development can provide valuable insights into the feeding behaviour and evolution of extinct organisms. The teeth of Theropoda, the only clade of predominantly predatory dinosaurs, are characterized by ziphodonty, the presence of serrations (denticles) on their cutting edges. Known today only in varanid lizards, ziphodonty is much more pervasive in the fossil record. Here we present the first model for the development of ziphodont teeth in theropods through histological, SEM, and SR-FTIR analyses, revealing that structures previously hypothesized to prevent tooth breakage instead first evolved to shape and maintain the characteristic denticles through the life of the tooth. We show that this novel complex of dental morphology and tissues characterizes Theropoda, with the exception of species with modified feeding behaviours, suggesting that these characters are important for facilitating the hypercarnivorous diet of most theropods. This adaptation may have played an important role in the initial radiation and subsequent success of theropods as terrestrial apex predators.

Synthesis and characterization of dental composites

NASA Astrophysics Data System (ADS)

Djustiana, Nina; Greviana, Nadia; Faza, Yanwar; Sunarso

2018-02-01

During the last few decades, the increasing demands in esthetic dentistry have led to the development of dental composites material that provide similar appearance to the natural teeth. Recently, esthetic trend was an issue which increase the demand for teeth restorations that is similar with the origin. The esthetics of dental composite are more superior compared to amalgam, since its color look similar with natural teeth. Various dental composites have been developed using many type of fillers such as amorphous silica, quartz), borosilicate, Li-Sr-Ba-Al glass and oxide: zirconia and alumina. Researchers in Faculty of Dentistry University of Padjadjaran have prepared dental composites using zirconia-alumina-silica (ZAS) system as the filler. The aim is to improve the mechanical properties and the esthetic of the dental composites. The ZAS was obtained from chemical grade purity chemicals and Indonesia's natural sand as precursors its characterization were also presented. This novel method covers the procedure to synthesis and characterize dental composites in Padjadjaran University and some review about dental composites in global research.

Modeling of automotive driveline system for reducing gear rattles

NASA Astrophysics Data System (ADS)

Shangguan, Wen-Bin; Liu, Xue-Lai; Yin, Yuming; Rakheja, Subhash

2018-03-01

A nonlinear torsional model for a driveline system with 4 degrees of freedom is proposed for studying gear rattle if a car is at idle. The time-varying meshing stiffness of geared teeth, gear backlash, and the damping from oil film are included in the model. The dynamic responses of the driveline system, such as clutch angular displacement, meshing force and relative displacement between geared teeth, are calculated using the presented model. The influences of stiffness and damping of a clutch on gear rattle of geared teeth in a generic transmission are investigated. Based on the calculation and analysis results, a design guideline to select clutch's stiffness and damping is developed to reduce gear rattle for a car at idle. Taking a generic driveline system of a passenger car as an example, the developed method is experimentally validated by comparing the baseline clutch and revised clutch, in terms of the measured noise inside engine compartment and cab and vibrations at transmission housing.

Developmental and evolutionary novelty in the serrated teeth of theropod dinosaurs

PubMed Central

Brink, K. S.; Reisz, R. R.; LeBlanc, A. R. H.; Chang, R. S.; Lee, Y. C.; Chiang, C. C.; Huang, T.; Evans, D. C.

2015-01-01

Tooth morphology and development can provide valuable insights into the feeding behaviour and evolution of extinct organisms. The teeth of Theropoda, the only clade of predominantly predatory dinosaurs, are characterized by ziphodonty, the presence of serrations (denticles) on their cutting edges. Known today only in varanid lizards, ziphodonty is much more pervasive in the fossil record. Here we present the first model for the development of ziphodont teeth in theropods through histological, SEM, and SR-FTIR analyses, revealing that structures previously hypothesized to prevent tooth breakage instead first evolved to shape and maintain the characteristic denticles through the life of the tooth. We show that this novel complex of dental morphology and tissues characterizes Theropoda, with the exception of species with modified feeding behaviours, suggesting that these characters are important for facilitating the hypercarnivorous diet of most theropods. This adaptation may have played an important role in the initial radiation and subsequent success of theropods as terrestrial apex predators. PMID:26216577

Histogenesis and disappearance of the teeth of the Mekong giant catfish, Pangasianodon gigas (Teleostei).

PubMed

Kakizawa, Yoshiko; Meenakarn, Wanpen

2003-12-01

Juveniles of the Mekong giant catfish, Pangasianodon gigas (Teleostei), have 3 sorts of tooth-upper and lower jaw teeth, palatal teeth, and pharyngeal teeth--but adults are toothless. To investigate the histogenesis and disappearance of the teeth, we made serial sections of the mouth and teeth of juvenile fish at 10 developmental stages (from ca. 8.5 to ca. 30 cm in total length) and examined them under scanning electron microscope and light microscope. Observations of teeth and surrounding tissues in the serial sections revealed the process of tooth resorption by active odontoclast-like cells. Numbers of jaw and palatal teeth decreased with age. When the fish reached ca. 14 cm in total length, the numbers of functional upper jaw teeth and successional tooth germs decreased rapidly, and the developmental rate of successional tooth germs slowed. When the fish reached ca. 24 cm, no teeth existed in the upper jaw. It is clear that tooth disappearance results from the shedding of functional teeth and the lack of replacement tooth germs.

Intentional replantation of adhesively reattached vertically fractured maxillary single-rooted teeth.

PubMed

Nizam, N; Kaval, M E; Gürlek, Ö; Atila, A; Çalışkan, M K

2016-03-01

To evaluate the clinical outcomes of intentionally replanted maxillary single-rooted teeth with vertical root fractures (VRFs) after being repaired extraorally using 4-methacryloxyethyl trimellitate anhydride/methacrylate-tri-n-butyl borane (4-META/MMA-TBB) resin cement. Twenty-one root filled maxillary single-rooted teeth with VRFs were evaluated. After atraumatic extraction, fractured fragments were adhesively cemented. The teeth were then replanted and splinted to the neighbouring teeth for 2 weeks. Plaque index (PI), gingival index (GI), probing depth (PD) and clinical attachment level (CAL) were assessed at baseline, 6 and 12 months, and radiographic evaluations were made using PAI scores at baseline and 12 months. Mobility was evaluated using periotest values (PTV) at baseline, 1, 3, 6 and 12 months. Replanted teeth, contralateral teeth (control teeth) and adjacent teeth were analysed statistically using repeated measures one-way anova, unpaired t-tests and Wilcoxon matched-pairs signed-rank tests. Two teeth were extracted in the first month after surgery. PI, GI, CAL and PD scores of the replanted teeth were significantly lower at 6 month (P < 0.0001 for all) and 12 month (P < 0.0001 for all) postoperatively when compared to baseline, but the values were not significantly different from those of the control and adjacent teeth. PTV of the test teeth increased significantly (P < 0.0001) after the intervention and decreased to baseline levels by month 12. PTVs were significantly higher (P < 0.05) at baseline, 1, 3 and 6 months in the test teeth when compared with the control teeth, but were not significantly different at month 12. PAI scores of teeth with VRF were significantly lower (P < 0.05) at 12 months compared with baseline. Adhesive cementation and intentional replantation were an effective treatment modality for this group of vertically fractured maxillary single-rooted teeth. The clinical periodontal parameters decrease by month 6, and the mobility returned to the physiological limits of natural teeth 12 months after replantation. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Endotoxin content in endodontically involved teeth. 1975.

PubMed

Schein, Benjamin; Schilder, Herbert

2006-04-01

Fluid was aspirated from the root canals of 40 endodontically involved teeth. This fluid was assayed for endotoxin with the limulus lysate test. Pulpless teeth contained greater concentrations of endotoxin than those with vital pulps. Symptomatic teeth also contained more endotoxin than asymptomatic teeth.

Early Pleistocene hominin deciduous teeth from the Homo antecessor Gran Dolina-TD6 bearing level (Sierra de Atapuerca, Spain).

PubMed

Bermúdez de Castro, José María; Martinón-Torres, María; Martín-Francés, Laura; Martínez de Pinillos, Marina; Modesto-Mata, Mario; García-Campos, Cecilia; Wu, Xiujie; Xing, Song; Liu, Wu

2017-07-01

During the last 13 years, the late Early Pleistocene Gran Dolina-TD6-2 level (Sierra de Atapuerca, northern Spain) has yielded an additional sample of 26 dental specimens attributed to Homo antecessor. In this report, we present a descriptive and comparative study of the six deciduous teeth. We provide external and internal morphological descriptions following classical terminology, as well as the mesiodistal and buccolingual measurements of the teeth. The internal morphology was described by means of micro-CT technique. The TD6 deciduous teeth preserve primitive features regarding the Homo clade, such as the presence of styles in lower and upper canines and developed anterior and posterior foveae in the dm 2 . However, other features related to the complexity of the crown morphology (e.g., cingulum) are not present in this sample. Furthermore, the great reduction of the talonid of the dm 1 s is also noteworthy. Despite the limited comparative evidence, the presence of a remarkably well-developed tuberculum molare in the dm 1 and dm 1 s from TD6 can be also considered a derived feature in the genus Homo. The TD6 hominins exhibit dental dimensions similar to those of other Pleistocene hominins. The dm 1 s are buccolingually elongated and the buccolingual diameter of ATD6-93 is the largest recorded so far in the Homo fossil record. This study expands the list of plesiomorphic features of H. antecessor, and provides some information on the evolutionary status of this species. However, the identification of some advanced traits evinces a step towards the derived morphology of European Pleistocene teeth. The study of the deciduous dentition confirms the mosaic pattern of H. antecessor morphology revealed in previous studies of this hominin sample. © 2017 Wiley Periodicals, Inc.

An epidemiological survey on the prevalence of equine peripheral dental caries in the United Kingdom and possible risk factors for its development.

PubMed

Borkent, D; Reardon, R J M; McLachlan, G; Smith, S; Dixon, P M

2017-07-01

Equine peripheral caries (PC) is an increasingly recognised disorder that causes premature wear of teeth and dental fractures and thus has major welfare implications. Little information is available on its prevalence or severity in UK horses and there are no proven associations with any risk factors. To document the prevalence of PC over a wide area of the UK, assess its intraoral distribution and severity in affected horses and examine for potential risk factors for its development. Cross sectional study. Experienced personnel were recruited for a UK wide dental survey on their patients during dental examinations. Established guidelines were used for grading PC. Frequency of PC occurrence was compared between teeth and dental arcades using McNemar's tests. Potential risk factors for PC were screened using univariable logistic regression prior to building a multivariable model. A total of 706 horses were examined by 25 participants, showing a 51.7% prevalence of PC (365/706). Some regional differences in prevalence were found. The PC primarily affected the cheek teeth with the 12 caudal being significantly more commonly affected than the 12 rostral cheek teeth. Most of the hypothesised risk factors including age, breed, sex, time at pasture and feeding of silage (haylage) were unproven. A limited association with moderate levels of concentrate feeding was observed. The presence of concurrent dental abnormalities were significantly associated with the likelihood of having PC. Not all regions in UK were included and there may be inconsistencies between examiners. Peripheral caries is common in British horses, primarily affecting the caudal cheek teeth. There was limited evidence of an association between feeding and PC. The association between PC and concurrent dental disorders indicates that these should be addressed in affected horses. © 2016 EVJ Ltd.

Two Body Wear of Newly Introduced Nanocomposite Teeth and Cross Linked Four Layered Acrylic Teeth: a Comparitive In Vitro Study.

PubMed

Ilangkumaran, R; Srinivasan, J; Baburajan, K; Balaji, N

2014-12-01

Wear of complete denture teeth results in compromise in denture esthetics and functions. To counteract this problem, artificial teeth with increased wear resistance had been introduced in the market such as nanocomposite teeth. The purpose of this study was to compare the amount of wear between nanocomposite teeth and acrylic teeth. Fifteen specimens were chosen from each group namely the nanocomposite teeth (SR_-PHONARES) and the acrylic teeth (ACRY PLUS). Maxillary premolar was only chosen for testing and the samples were customized according to the specifications of the pin on disc machine. Pin on disc machine is a two body tribometer which quantifies the amount of wear under a specific load and time. Test samples were mounted on to the receptacle of the pin on disc machine and tested under a load of 0.3 kg for 1,000 cycles of rotation against a 600 grit emery paper. The amount of wear is displayed from the digital reading obtained from the pin on disc machine. After statistical analysis, it was found that, the amount of wear is more in four layered acrylic teeth. The p value obtained is 0.002 (<0.005) thus implies that the difference in wear between nanocomposite teeth and acrylic teeth is statistically significant. Though the nanocomposite teeth has less amount of wear than the four layered acrylic teeth, the difference is very less and adds only to a little clinical significance but the cost of the nanocomposite is four times that of the acrylic teeth. Further clinical studies must be performed to confirm our results.

The study of barium concentration in deciduous teeth, impacted teeth, and facial bones of Polish residents.

PubMed

Fischer, Agnieszka; Malara, Piotr; Wiechuła, Danuta

2014-10-01

The study determines the concentration of Ba in mineralized tissues of deciduous teeth, permanent impacted teeth, and facial bones. The study covers the population of children and adults (aged 6-78) living in an industrial area of Poland. Teeth were analyzed in whole, with no division into dentine and enamel. Facial bones and teeth were subjected to the following preparation: washing, drying, grinding in a porcelain mortar, sample weighing (about 0.2 g), and microwave mineralization with spectrally pure nitric acid. The aim of the study was to determinate the concentration of Ba in deciduous teeth, impacted permanent teeth, and facial bones. The concentration of barium in samples was determined over the ICP OES method. The Ba concentration in the tested bone tissues amounted to 2.2-15.5 μg/g (6.6 μg/g ± 3.9). The highest concentration of Ba was present in deciduous teeth (10.5 μg/g), followed by facial bones (5.2 μg/g), and impacted teeth (4.3 μg/g) (ANOVA Kruskal-Wallis rank test, p = 0.0002). In bone tissue and impacted teeth, Ba concentration increased with age. In deciduous teeth, the level of Ba decreased with children's age.

Oral health status in a population in Northern Norway.

PubMed

Norheim, P W

1979-01-01

Information concerning oral health status was obtained through a clinical and radiographic examination of 297 persons aged 20--69 years out of a population of 358 persons living in a coastal community in Northern Norway. The oral health was generally poor. 71% had one or more remaining teeth and the dentulous persons had a mean number of 18 remaining teeth. The mean number of DMF teeth was 27,3 while the mean number of decayed teeth was 4,9 and filled teeth 12,0 giving a percent of decayed and filled teeth of 27 and 65 respectively. Only every fourth dentulous person had one or more crowns and/or bridge units and 4% of all teeth had been treated endodontically. 41% of the teeth had visible plaque and 56% of the teeth had one or more gingival margins bleeding after gentle probing. One fourth of all teeth had gingival pockets exceeding 3 mm and 17% of all teeth showed a bone loss of 20% or more. The number of remaining teeth decreased with increasing age and decreasing income and/or social class. In general, women, young people and people with a high socioeconomic status had less caries, better oral hygiene and periodontal condition and had received more restorative dental care than the remaining part of the population.

Does erosion progress differently on teeth already presenting clinical signs of erosive tooth wear than on sound teeth? An in vitro pilot trial.

PubMed

Carvalho, Thiago Saads; Baumann, Tommy; Lussi, Adrian

2016-07-07

Erosive tooth wear (ETW) is clinically characterized by a loss of tooth surface, and different enamel depths may have different susceptibility to demineralization. Therefore, the aim of this in vitro pilot study was to assess if the progression of erosive demineralization is faster on teeth already presenting signs of ETW when compared to originally sound teeth. We selected 23 central incisors: 14 were clinically sound (Sound) and 9 presented clinical signs of early erosive tooth wear (ETW-teeth). The teeth were embedded in resin, leaving an uncovered window of native enamel (6.69 ± 2.30 mm(2)) on the incisal half of the labial surface. We measured enamel surface reflection intensity (SRI) initially and after each consecutive erosive challenge (1 % citric acid, total of 4, 8, 12, 16, 20 and 24 min). Calcium released to the citric acid was measured with an atomic absorption spectrometer. We observed higher initial SRI values in ETW-teeth than in Sound teeth (p = 0.007). During in vitro erosive demineralization, we observed that erosion on originally Sound teeth progressed significantly slower (p = 0.033) than on ETW-teeth: SRI decreased by 75 % (from 100 to 25 %) on Sound teeth, and by 89 % (from 100 to 11 %) on ETW-teeth. Calcium release increased during erosion, but presented no significant differences (p = 0.643) between originally Sound (0.031 μmol/mm(2)) and ETW-teeth (0.032 μmol/mm(2)). There was satisfactory correlation between calcium release and rSRI values (r s  = -0.66). The optical reflectometer distinguished originally sound teeth from those with signs of ETW, and the results suggest that acid demineralization progresses differently on teeth already presenting clinical signs of ETW than on sound teeth.

A 57-year follow-up of occlusal changes, oral health, and attitudes toward teeth.

PubMed

Stenvik, Arild; Espeland, Lisen; Berg, Rolf E

2011-04-01

Very few studies have addressed long-term development and risks associated with untreated malocclusion. The purpose of this study was to examine changes in occlusion in a lifelong perspective and to compare oral health and attitudes toward teeth among persons with malocclusion with those having normal occlusion. In 1950 an epidemiologic survey of 2349 8-year-olds was conducted and included 4 intraoral photographs. Three selected samples with different malocclusions (deep bite, crossbite, or irregular teeth) and 1 sample with normal occlusion (a total of 183 subjects) were, 57 years later, invited for examination and an extensive interview about dental experiences and attitudes. Sixty-nine responded (38%) and constitute the subjects studied. Malocclusion remained the same or worsened except in subjects having deep bite in childhood, which in some improved and in others became worse. Crowding generally increased. Sixteen persons reported moderate or severe temporomandular joint (TMJ) problems, and of these 7 belonged to the group with crossbite in childhood. With few exceptions, the subjects in all samples had good oral hygiene, visited the dentist regularly, and had well-preserved dentitions. Mean number of missing teeth was significantly lower among those with normal occlusion compared with the malocclusion groups. Individuals with normal occlusion responded favorably to all questions related to attitudes and experiences about their teeth, while responses in the malocclusion groups varied. Persons with the particular malocclusions examined experienced more problems related to teeth later in life compared with those having normal occlusion in childhood. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Prevalence of hypodontia in nine- to fourteen-year-old children who attended the Mashhad School of Dentistry.

PubMed

Ajami, Behgat-al-molok; Shabzendedar, Mahboobeh; Mehrjerdian, Maryam

2010-01-01

Hypodontia is defined as the congenital absence of one or a few teeth, and is also the most common anomaly in dental development. This condition occurs either individually or as part of the symptoms of a syndrome, and it is more common in permanent teeth than in deciduous teeth, reporting a prevalence of between 1.6 and 9.6%. The objective of this study is to investigate the prevalence of hypodontia for permanent teeth in nine- to 14-year-old children who attended the Mashhad School of Dentistry in 2007. We conducted this descriptive, analytical, cross-sectional study, to determine the mentioned aims. In this descriptive, cross-sectional study, panoramic radiographs belonging to 600 children (351 girls and 249 boys), aged nine to 14 years, were available for examination. All related findings were recorded in the respective forms. The data were processed using Exact and Chi-square tests. The prevalence of hypodontia in the girls was 9.2%, in the boys 8.8%, and in both sexes combined 9%. The most and the least frequent cases of absent teeth were the mandibular second premolars and the maxillary central incisor (only one child), respectively. The most commonly absent teeth were the mandibular second premolars, the maxillary lateral incisors, the mandibular central incisor, and the maxillary second premolars, in that order. This study showed a high frequency of hypodontia among the understudied population. Thus, due to the complicated treatment, accurate examination of children for on-time diagnosis of this developmental anomaly is crucial.

Strontium-90 concentration measurements in human bones and teeth in Greece.

PubMed

Stamoulis, K C; Assimakopoulos, P A; Ioannides, K G; Johnson, E; Soucacos, P N

1999-05-19

Strontium-90 concentration was measured in human bones and teeth collected in Greece during the period 1992-1996. One hundred and five bone samples, mainly cancellous bone, and 108 samples, taken from a total of 896 individual teeth were processed. Samples were classified according to the age and sex of the donors. Samples were chemically pre-treated according to a specially devised method to enable extraction of 90Y, at equilibrium with 90Sr in the original sample. Subsequently, 90Y beta activity was measured with a gas proportional counter. Radiostrontium concentration in bone samples showed small variations with respect to age or sex, with an average value of 30 mBq 90Sr/g Ca. However, 90Sr concentration measurements in teeth demonstrated a pronounced structure, which clearly reflects contamination from the 1960s atmospheric nuclear weapons tests and the more recent Chernobyl accident. This difference is attributed to the different histological structure of skeletal bones and teeth, the later consisting mainly of compact bone. An age-dependent model for radiostrontium concentration in human bones and teeth is developed which is able to successfully reproduce the experimental data. Through a fitting process, the model also yielded calcium turnover rates for compact bone, as a function of age, as well as an estimate of radiostrontium contamination of foodstuffs in Greece for the past four decades. The results obtained in this study indicate that radiostrontium environmental contamination which resulted from the atmospheric nuclear weapons tests in the 1960s, exceed by far that caused by the Chernobyl accident.

Tooth - abnormal shape

MedlinePlus

Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

Ectodermal dysplasia (ED) syndrome.

PubMed

Chee, Siew-Yin; Wanga, Chung-Hsing; Lina, Wei-De; Tsaia, Fuu-Jen

2014-01-01

Ectodermal dysplasia (ED) syndrome comprises a large, heterogeneous group of inherited disorders that are defined by primary defects in the development of 2 or more tissues derived from the embryonic ectoderm. The tissues primarily involved are the skin and its appendages (including hair follicles, eccrine glands, sebaceous glands, nails) and teeth. The clinical features include sparse hair, abnormal or missing teeth, and an inability to sweat due to lack of sweat glands. One such case report of ectodermal dysplasia is presented here.

Radiographic localization of unerupted teeth: further findings about the vertical tube shift method and other localization techniques.

PubMed

Jacobs, S G

2000-10-01

The parallax method (image/tube shift method, Clark's rule, Richards' buccal object rule) is recommended to localize unerupted teeth. Richards' contribution to the development of the parallax method is discussed. The favored method for localization uses a rotational panoramic radiograph in combination with an occlusal radiograph involving a vertical shift of the x-ray tube. The use of this combination when localizing teeth and supernumeraries in the premolar region is illustrated. When taking an occlusal radiograph to localize an unerupted maxillary canine, clinical situations are presented where modification of the vertical angulation of the tube of 70 degrees to 75 degrees or of the horizontal position of the tube is warranted. The limitations of axial (true, cross-sectional, vertex) occlusal radiographs are also explored.

A previously unreported association between Nance-Horan syndrome and spontaneous dental abscesses.

PubMed

Hibbert, Sally

2005-02-01

Atypical dentofacial structures may be the first indicator of other anomalies linked to a syndrome. This case describes the management of a 9-year-old girl referred for the routine management of supernumerary teeth. The anomalous form of her teeth, together with multiple supernumerary units and a history of congenital cataracts, were suggestive of a diagnosis of Nance-Horan syndrome. This is an X-linked disorder, in which females usually demonstrate mild expression; this case was unusual in respect to the marked phenotype expressed. Unusually, the girl developed 2 spontaneous abscesses of her noncarious upper incisor teeth; a feature never previously described in this syndrome. This report details the patient's dental management and discusses the possible pathogenesis of the dental abscesses, together with the genetic implications of this syndrome.

Employing Tip-Edge brackets on canines to simplify straight-wire mechanics.

PubMed

Rocke, R T

1994-10-01

The straight-wire appliance was developed in part to reduce wire bending and therefore make treatment results more predictable. Because tip prescription is built into the bracket slots, teeth are held at their final crown angulations throughout treatment. Straight-wire brackets are used in an attempt to produce bodily tooth movement. However, teeth tend to tip when a force is applied. This tipping, especially when canines are retracted, can deflect the arch wire causing supereruption of the incisors with a resultant increase in anterior overbite and an open bite in the canine/premolar area. Placing Tip-Edge brackets (TP Orthodontics, Inc., LaPorte, Ind.) on canines and employing tipping and uprighting mechanics on these teeth can overcome these problems. Two cases are presented to illustrate this approach to treatment.

Radiographic, computed tomographic, gross pathological and histological findings with suspected apical infection in 32 equine maxillary cheek teeth (2012-2015).

PubMed

Liuti, T; Smith, S; Dixon, P M

2018-01-01

Equine maxillary cheek teeth apical infections are a significant disorder because of frequent spread of infection to the supporting bones. The accuracy of computed tomographic imaging (CT) of this disorder has not been fully assessed. To compare the radiographic and CT findings in horses diagnosed with maxillary cheek teeth apical infections with pathological findings in the extracted teeth to assess the accuracy of these imaging techniques. Observational clinical study. Thirty-two maxillary cheek teeth (in 29 horses) diagnosed with apical infections by clinical, radiographic and principally by CT examinations, were extracted orally. The extracted teeth were subjected to further CT, gross pathological and histological examinations. Four normal teeth extracted from a cadaver served as controls. Pulpar and apical changes highly indicative of maxillary cheek teeth apical infection were present in all 32 teeth on CT, but in just 17/32 teeth (53%) radiographically. Gross pulpar/apical abnormalities and histological pulpar/periapical changes were present in 31/32 (97%) extracted teeth. On CT, one tooth contained small gas pockets in the apical aspect of one pulp and adjacent periodontal space, however no pathological changes were found following its extraction. The study is descriptive and is confined to a small number of cases. This study showed a 97% agreement between CT diagnosis of maxillary cheek teeth apical infection and the presence of pathological changes in the extracted teeth, confirming the diagnostic accuracy of CT compared with radiography for this disorder. © 2017 EVJ Ltd.

Dental fluorosis in children in areas with fluoride-polluted air, high-fluoride water, and low-fluoride water as well as low-fluoride air: a study of deciduous and permanent teeth in the Shaanxi province, China.

PubMed

Ruan, Jian Ping; Bårdsen, Asgeir; Astrøm, Anne Nordrehaug; Huang, Rui Zhe; Wang, Zhi Lun; Bjorvatn, Kjell

2007-04-01

The aim of the study was to assess dental fluorosis (DF) in the deciduous and permanent teeth of children in areas with high-F coal (area A) and high-F water (area C) compared to children from area B, with low-F water and coal. 596 children were examined. DF was assessed by TF-score. F-content of indoor air, drinking water, coal, tea, rice, and maize was analyzed. F-content of air and coal ranged from 3.2 microg/m(3) and 25.8 mg/kg (area B), 3.8 microg/m(3) and 36.3 mg/kg (area C) to 56.8 microg/m(3) and 713.1 mg/kg (area A). Likewise, mean F-content of water ranged from approximately 0.50 mg/l (areas A and B) to 3.64 mg/l (area C). F-content of tea leaves was similar in all three areas. Maize and rice contained <5 mg F/kg. Prevalence of primary teeth with DF was 49.1%, 2.0%, and 66.8% in areas A, B, and C, respectively. Similarly, DF was found in 96.7% (area A), 19.6% (area B), and 94.4% (area C) of the permanent teeth. Severe fluorosis (TF > or = 5) was found in area A (47.0%) and area C (36.1%) (p<0.01). Early erupting teeth had slightly higher mean TF-scores in area A than in area C. DF was prevalent in both dentitions in areas A and C. Similarity in percentages of DF may indicate that indoor air with approximately 60 microg F/m(3) and drinking water with 3.6 mg F/L are similarly toxic to developing permanent teeth. The percentage of deciduous teeth with DF was significantly lower in area A compared to area C. Where low-F coal and low-F water were used (area B), approximately 20% of permanent teeth had DF, indicating a relatively low tolerance to fluoride in Chinese children brought up under the present living conditions.

Pulpal safety of 9.6 microm TEA CO2 laser used for caries prevention.

PubMed

Goodis, Harold E; Fried, Daniel; Gansky, Stuart; Rechmann, Peter; Featherstone, John D B

2004-01-01

Lasers are used for several procedures involving hard and soft tissues of the oral cavity. A potential future application is the use of the CO2 laser to alter the surface structure of tooth enamel to render it more resistant to caries. A new 9.6 microm wavelength transverse excited atmospheric pressure (TEA) CO2 laser (Argus Photonics, Jupiter, FL) has been investigated as a device that can be used for this purpose without harming the dental pulp. Erupted caries- and restoration-free third molars (n = 24 participants; 74 teeth) were used in the study. Teeth were irradiated at an incident fluence of 1.5 J/cm2, a repetition rate of 10 Hz and a spot size 1 mm in diameter. At the low and high settings, 200-400 pulses at 5-8 microseconds pulse duration were delivered at 12 mJ per pulse for a total energy of 2.4 or 4.8 J delivered for 20 or 40 seconds, respectively. Other teeth were subjected to a sham dental procedure (positive control) or no procedure (negative control). Prior to testing, radiographs were taken of all teeth, and they were assessed pulpally using heat, cold, and electricity to determine vitality. The teeth were removed either immediately or at 1 week or 1 month after testing. Teeth were bioprepared and examined histologically for signs of inflammation. Only one tooth developed symptoms of sensitivity to cold for 10 days following exposure to the high power level. The sensitivity was of fleeting duration and was judged to be reversible pulpitis. All teeth tested responded normally at pre-testing and pre-extraction time periods. Histological examination of all teeth disclosed no indication of an inflammatory response in the pulp tissue at any time point. All sections appeared normal with no changes seen in the normal pulpal morphology. We conclude that the 9.6 microm wavelength laser causes no permanent/serious pulpal damage at the energy levels used and can be used safely for caries prevention treatments in humans.

Root morphology and development of labial inversely impacted maxillary central incisors in the mixed dentition: a retrospective cone-beam computed tomography study.

PubMed

Sun, Hao; Wang, Yi; Sun, Chaofan; Ye, Qingsong; Dai, Weiwei; Wang, Xiuying; Xu, Qingchao; Pan, Sisi; Hu, Rongdang

2014-12-01

The aim of this study was to analyze 3-dimensional data of root morphology and development in labial inversely impacted maxillary central incisors. Cone-beam computed tomography images from 41 patients with impacted incisors were divided into early and late dental age groups according to their dental age. Sagittal slices in which the labiolingual width of the tooth was the widest in the axial view were evaluated. The inverse angle, the dilaceration angle, and the length of both impacted and homonym teeth were evaluated with SimPlant Pro software (version 13.0; Materialise Dental NV, Leuven, Belgium). The Student t test indicated that the lengths of the impacted teeth were significantly shorter than those of the homonym teeth (P <0.05), and the root lengths of the early dental age group were significantly shorter than those of the late dental age group. The results from chi-square tests indicated that the incidence of dilacerations was significantly higher in the late dental age group when compared with the early dental age group. Multiple regression analyses indicated that the independent variables for root length of the impacted teeth were dental age (β = 0.958; P <0.001) and length of the nondilacerated part of the root (β = 0.435; P <0.001). Dilaceration was more common in the late dental age group. The roots of labial inversely impacted maxillary central incisors continue developing, but their potential is limited. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

[Three-dimensional computer aided design for individualized post-and-core restoration].

PubMed

Gu, Xiao-yu; Wang, Ya-ping; Wang, Yong; Lü, Pei-jun

2009-10-01

To develop a method of three-dimensional computer aided design (CAD) of post-and-core restoration. Two plaster casts with extracted natural teeth were used in this study. The extracted teeth were prepared and scanned using tomography method to obtain three-dimensional digitalized models. According to the basic rules of post-and-core design, posts, cores and cavity surfaces of the teeth were designed using the tools for processing point clouds, curves and surfaces on the forward engineering software of Tanglong prosthodontic system. Then three-dimensional figures of the final restorations were corrected according to the configurations of anterior teeth, premolars and molars respectively. Computer aided design of 14 post-and-core restorations were finished, and good fitness between the restoration and the three-dimensional digital models were obtained. Appropriate retention forms and enough spaces for the full crown restorations can be obtained through this method. The CAD of three-dimensional figures of the post-and-core restorations can fulfill clinical requirements. Therefore they can be used in computer-aided manufacture (CAM) of post-and-core restorations.

Effect of magnetic attachment with stress breaker on lateral stress to abutment tooth under overdenture.

PubMed

Gonda, T; Ikebe, K; Ono, T; Nokubi, T

2004-10-01

Recently, a newly developed magnetic attachment with stress breaker was used in retentive components in overdentures. Excessive lateral stress has a more harmful effect on natural teeth than axial stress, and the magnetic attachment with stress breaker is expected to reduce lateral forces on abutment teeth and protect it teeth from excessive stress. However, the properties of this retainer have not yet been determined experimentally. This study compares the lateral forces on abutment teeth for three retainers under loading on the denture base in a model study. A mandibular simulation model is constructed to measure lateral stress. Three types of retentive devices are attached to the canine root. These devices include the conventional root coping, the conventional magnetic attachment and the new magnetic attachment with stress breaker. For each retentive device, load is generated on the occlusal table of the model overdenture, and the lateral stress on the canine root and the displacement of the overdenture measured. The magnetic attachment with stress breaker does not displace the denture and exhibits lower lateral stress in the canine root than conventional root coping and magnetic attachments.

Evidence from tooth surface morphology for a posterior maxillary origin of the proteroglyph gang

USGS Publications Warehouse

Jackson, K.; Fritts, T.H.

1995-01-01

Although the front-fanged venom delivery system of the Elapidae is believed to be derived from an aglyphous or opisthoglyphous colubroid ancestor, opinion is divided as to the end of the maxilla on which the proteroglyph fang originated. This study was undertaken to determine whether the evolutionary precursor of the proteroglyph fang was (a) a grooved posterior fang which migrated anteriorly, or (b) an enlarged anterior tooth which secondarily developed a groove for the conduction of venom. The surface morphology of the maxillary teeth of colubrid genera was examined using scanning electron microscopy. Ridges present on the lingual and labial surfaces of anterior maxillary teeth and on the anterior and posterior surfaces of posterior maxillary teeth were identified as morphological markers of potential value in distinguishing the anterior and posterior maxillary teeth of colubrid snakes, and in determining the origin of the proteroglyph fang. Patterns of ridges on the surfaces of elapid fangs examined were found to be consistent with the hypothesis that the evolutionary precursor of the proteroglyph fang was an opisthoglyph fang which migrated anteriorly.

Clinical outcomes for teeth treated with electrospun poly(ε-caprolactone) fiber meshes/mineral trioxide aggregate direct pulp capping.

PubMed

Lee, Li-Wan; Hsiao, Sheng-Huang; Hung, Wei-Chiang; Lin, Yun-Ho; Chen, Po-Yu; Chiang, Chun-Pin

2015-05-01

Mineral trioxide aggregate (MTA) is a biocompatible material for direct pulp capping. This study was designed to compare the clinical outcomes of pulp-exposed teeth treated with either poly(ε-caprolactone) fiber mesh (PCL-FM) as a barrier for MTA (so-called PCL-FM/MTA) or MTA direct pulp capping. Sixty human vital teeth were evenly divided into 4 groups (n = 15 in each group). Teeth in groups 1 and 3 had pulp exposure <1 mm in diameter, whereas teeth in groups 2 and 4 had pulp exposure of 1-1.5 mm in diameter. Teeth in groups 1 and 2 were treated with PCL-FM/MTA direct pulp capping, and those in groups 3 and 4 were treated with MTA direct pulp capping. Teeth treated with PCL-FM/MTA direct pulp capping needed a significantly shorter mean duration for dentin bridge formation than teeth treated with MTA direct pulp capping. Moreover, teeth with pulp exposure <1.0 mm in diameter needed a significantly shorter mean duration for dentin bridge formation than teeth with pulp exposure of 1-1.5 mm in diameter after either PCL-FM/MTA or MTA direct pulp capping treatment. In addition, teeth treated with PCL-FM/MTA direct pulp capping formed an approximately 3-fold thicker dentin bridge than teeth treated with MTA direct pulp capping 8 weeks or 3 months later. Furthermore, none of the teeth treated with PCL-FM/MTA direct pulp capping showed tooth discoloration after treatment for 3 months. PCL-FM/MTA is a better combination material than MTA alone for direct pulp capping of human permanent teeth. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

[The statistical analysis for the use of the 55,787 finished resin teeth].

PubMed

Wu, Shu-hong; Yu, Hai-yang; Wang, Lu; Xu, Ling; Xiao, Zhi-li

2010-08-01

To analyze the use situation of finished resin teeth for the different location, and to provide reference for manufacturers of finished resin teeth and all the buyers. To analyze the use situation of finished resin teeth in the Dental Laboratory of the Affiliated Hospital of Stomatology of Chongqing Medical University from January 2006 to December 2008 by using statistic methods. During the use of 55,787 finished resin teeth, the study found some rules. (1) The top use of finished resin teeth was D6 with the percentage of 5.31%, and the lowest use of finished resin teeth was D3 with the percentage of 1.94%. (2) Except the maxillary canines and the mandibular lateral incisors, there was no significant difference between the usage of other same name finished resin teeth (P > 0.05). (3) Among all finished resin teeth, the usage of section B exceeded section A, and the usage of maxillary finished resin teeth exceeded mandibular finished resin teeth (P < 0.05). (4) The use of the complete denture and single complete denture was about 1/3 of the total usage of finished resin teeth. (5) Except the use situation of complete denture and single complete denture, the frequency of simultaneously using mandibular left and right central incisors was the most with the percentage of 81.46%, for the frequency of simultaneously using maxillary left and right canines was 43.26% of the total, which was the lowest. There is significant difference in the use frequency of finished resin teeth for different location. For such reason, the manufacturers should produce finished resin teeth pro rata as well as the buyers for their purchase.

Relationship of Number of Missing Teeth to Hip Fracture in Elderly Patients: A Cohort Pilot Study.

PubMed

Priebe, Jennifer; Wermers, Robert A; Sems, Stephen A; Viozzi, Christopher F; Koka, Sreenivas

2017-09-15

To determine the relationship between the number of missing natural teeth or remaining natural teeth and osteoporotic hip fracture in elderly patients and to determine the relationship between the number of missing teeth or remaining teeth and osteoporotic fracture risk assessment (FRAX) probability. Number of missing teeth was determined by clinical oral exam on a total of 100 subjects, 50 with hip fractures and 50 without. Ten-year fracture risk and hip fracture risk probabilities were calculated using the FRAX tool. Statistical analyses were performed to determine strength of associations between number of missing natural teeth and likelihood of experiencing a fracture. Degree of correlation between number of missing natural teeth and FRAX probabilities were calculated. There appears to be an association between the number of missing natural teeth and hip fractures. For every 5-tooth increase in the number of missing teeth, the likelihood of being a subject in the hip fracture group increased by 26%. Number of missing natural teeth was positively correlated with FRAX overall fracture and hip fracture probability. Number of missing natural teeth may be a valuable tool to assist members of medical and dental teams in identifying patients with higher FRAX scores and higher likelihood of experiencing a hip fracture. Additional research is necessary to validate these findings. © 2017 by the American College of Prosthodontists.

Skeletal and dental effects on rats following in utero/lactational exposure to the non-dioxin-like polychlorinated biphenyl PCB 180

PubMed Central

Romero, Ashly N.; Herlin, Maria; Finnilä, Mikko; Korkalainen, Merja; Håkansson, Helen; Viluksela, Matti

2017-01-01

Polychlorinated biphenyls (PCBs) are a large class of persistent organic pollutants that are potentially harmful to human and wildlife health. Although a small number of dioxin-like (DL) PCBs are well characterized, the majority of PCBs have non-dioxin-like (NDL) modes of action and biological effects that are less understood. We conducted a dose-response study of the skeletal and dental effects of in utero/lactational exposure to 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180), a NDL PCB congener that is abundantly present in the environment and foods, including mother’s milk. In a sample of 35- and 84-day-old male and female offspring from pregnant rats exposed to different doses of PCB 180 (0, 10, 30, 100, 300, and 1000 mg/kg bw), we measured the three-dimensional (3D) coordinates of 27 landmarks on the craniofacial skeleton with a Microscribe G2X system, the buccolingual width of all molars with digital sliding calipers, and a variety of tibial parameters with peripheral quantitative computed tomography (pQCT) and a biomechanical testing apparatus. The landmark coordinates were analyzed for variation in size, shape, and fluctuating asymmetry (FA) using MorphoJ software, showing no effects on cranial size, on FA in females only (i.e., decreased asymmetry), and on shape in both sexes (i.e., decreased facial length and shift in the palatal suture). In the maxillary teeth, females in the highest dose group showed a significant decrease of 0.1 mm (p = 0.033) of the second molar only, whereas males in most dose groups showed average increases of 0.1 mm (p = 0.006–0.044) in all three molars. In the mandibular teeth, the only significant response to PCB 180 exposure was the average increase of 0.1 mm (p = 0.001–0.025) in the third molars of males only. Males also shower greater sensitivity in postcranial effects of increased tibial length and decreased cortical bone mass density, although only females showed significant effects on tibial bone area and thickness. These results demonstrate marked sex differences in effects of PCB 180, which can be attributed to differences in their underlying biological mechanisms of toxicity. Furthermore, although tooth and bone development are targets of both DL and NDL compounds, this study shows that there are marked differences in their mechanisms and effects. PMID:28957439

Skeletal and dental effects on rats following in utero/lactational exposure to the non-dioxin-like polychlorinated biphenyl PCB 180.

PubMed

Romero, Ashly N; Herlin, Maria; Finnilä, Mikko; Korkalainen, Merja; Håkansson, Helen; Viluksela, Matti; Sholts, Sabrina B

2017-01-01

Polychlorinated biphenyls (PCBs) are a large class of persistent organic pollutants that are potentially harmful to human and wildlife health. Although a small number of dioxin-like (DL) PCBs are well characterized, the majority of PCBs have non-dioxin-like (NDL) modes of action and biological effects that are less understood. We conducted a dose-response study of the skeletal and dental effects of in utero/lactational exposure to 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180), a NDL PCB congener that is abundantly present in the environment and foods, including mother's milk. In a sample of 35- and 84-day-old male and female offspring from pregnant rats exposed to different doses of PCB 180 (0, 10, 30, 100, 300, and 1000 mg/kg bw), we measured the three-dimensional (3D) coordinates of 27 landmarks on the craniofacial skeleton with a Microscribe G2X system, the buccolingual width of all molars with digital sliding calipers, and a variety of tibial parameters with peripheral quantitative computed tomography (pQCT) and a biomechanical testing apparatus. The landmark coordinates were analyzed for variation in size, shape, and fluctuating asymmetry (FA) using MorphoJ software, showing no effects on cranial size, on FA in females only (i.e., decreased asymmetry), and on shape in both sexes (i.e., decreased facial length and shift in the palatal suture). In the maxillary teeth, females in the highest dose group showed a significant decrease of 0.1 mm (p = 0.033) of the second molar only, whereas males in most dose groups showed average increases of 0.1 mm (p = 0.006-0.044) in all three molars. In the mandibular teeth, the only significant response to PCB 180 exposure was the average increase of 0.1 mm (p = 0.001-0.025) in the third molars of males only. Males also shower greater sensitivity in postcranial effects of increased tibial length and decreased cortical bone mass density, although only females showed significant effects on tibial bone area and thickness. These results demonstrate marked sex differences in effects of PCB 180, which can be attributed to differences in their underlying biological mechanisms of toxicity. Furthermore, although tooth and bone development are targets of both DL and NDL compounds, this study shows that there are marked differences in their mechanisms and effects.

Early Childhood Caries: A Review.

PubMed

Alazmah, Abdulfatah

2017-08-01

To review and update the current knowledge about early childhood caries (ECC) and its etiology, prevalence, risk factors, management, and preventive strategies. Early childhood caries is a disease affecting significantly both well-developed and industrial nations. The ECC can significantly affect the child's quality of life, as it may lead to infection, swelling, pain, and other symptoms. The ECC affects children after eruption of primary teeth until age of around 5 years. The ECC affects all parts of the tooth including the smooth surface. Upper anterior teeth and primary molars are usually affected. The lower anterior teeth are less likely affected. The risk factors for ECC are diet, bacteria, and host susceptibility. The additional factors, such as presence of enamel defect and the feeding practices also contribute to the initiation and progress of ECC. Dentists must focus on utilizing existing techniques to distinguish indications of right on time and propelled caries and give guidance on the best way to counteract and control caries in children. Approaches should be directed to preventive caries control strategies among children. Preventing and controlling the development of ECC among children is important to maintain effective eating, speech development, and formation of a positive self-image.

Teething troubles?

PubMed

McIntyre, G T; McIntyre, G M

2002-03-09

The relationship between the eruption of the deciduous teeth and the general health of infants has been documented for over 5,000 years. A variety of physical disturbances (anything from minor upsets to potentially fatal illnesses) have historically been attributed to teething, however a number of recent publications have alluded to a clarification of some of the disputed features of teething. It is now accepted that the localised symptoms of teething vary between individuals, however, 'teething' continues to be an inappropriate diagnosis proffered by both healthcare professionals and lay people. Severe systemic upsets are unrelated to teething and, if present, the infant should be promptly referred to a physician for an accurate diagnosis and appropriate treatment. The treatment modalities used in teething have been diverse throughout the ages, frequently depending on the tenets of the medical profession and lay people, but now principally involve pain relief. This article examines the signs and symptoms frequently attributed to teething and their possible alternative causes. The contemporary principles of the management of teething are discussed, including supportive measures, the diverse range of available topical and systemic pharmacological preparations and the 'alternative' holistic therapies.

Regenerative endodontics: a true paradigm shift or a bandwagon about to be derailed?

PubMed

Nazzal, H; Duggal, M S

2017-02-01

Regenerative endodontic techniques (RETs) have been hailed as a paradigm shift for the management of traumatised non-vital immature permanent anterior teeth. In this article the aim was to critically appraise the literature with regards to the outcome of regenerative endodontics on root development. Critical review of the literature where regenerative endodontic techniques have been used in the management of immature non-vital teeth with continuation of root development as the main outcome reported. Most studies published were in the form of case reports and series with very few randomised controlled trials with a high risk of bias. Continuation of root development following the use of RET has been shown to be unpredictable at best with lower success in those teeth losing vitality as a result of dental trauma. Despite the high success of regenerative endodontics in terms of periodontal healing including resolution of clinical and radiographic signs and symptoms of infection, continuation of root development remains an unpredictable outcome. The use of a blood clot as a scaffold in regenerative endodontics should be reviewed carefully as that might offer an environment for repair rather than regeneration. In addition, preservation of structures, such as Hertwig's epithelial root sheath, may have an important bearing on the success of this approach and should be further investigated.

N-cadherin is required for cytodifferentiation during zebrafish odontogenesis.

PubMed

Verstraeten, B; van Hengel, J; Sanders, E; Van Roy, F; Huysseune, A

2013-04-01

N-cadherin is a well-studied classic cadherin involved in multiple developmental processes and is also known to have a signaling function. Using the zebrafish (Danio rerio) as a model, we tested the hypothesis that tooth morphogenesis is accompanied by dynamic changes in N-cadherin distribution and that absence of N-cadherin disturbs tooth development. N-cadherin, encoded by the gene cdh2, is absent during the initiation and morphogenesis stages of both primary (first-generation) and replacement teeth, as demonstrated by immunohistochemistry. However, N-cadherin is up-regulated at the onset of differentiation of cells of the inner dental epithelium and the dental papilla, i.e., the ameloblasts and odontoblasts, respectively. In the inner dental epithelium, N-cadherin is co-expressed with E-cadherin, excluding the occurrence of cadherin switching such as observed during human tooth development. While early lethality of N-cadherin knockout mice prevents any functional study of N-cadherin in mouse odontogenesis, zebrafish parachute (pac) mutants, deficient for N-cadherin, survive beyond the age when primary teeth normally start to form. In these mutants, the first tooth forms, but its development stops at the early cytodifferentiation stage. N-cadherin deficiency also completely inhibits the development of the other first-generation teeth, possibly due to the absence of N-cadherin signaling once the first tooth has differentiated.

Quantitative analysis of trace metal accumulation in teeth using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Samek, O.; Beddows, D. C. S.; Telle, H. H.; Morris, G. W.; Liska, M.; Kaiser, J.

The technique of laser ablation is receiving increasing attention for applications in dentistry, specifically for the treatment of teeth (e.g. drilling of micro-holes and plaque removal). In the process of ablation a luminous micro-plasma is normally generated which may be exploited for elemental analysis. Here we report on quantitative Laser-Induced Breakdown Spectroscopy (LIBS) analysis to study the presence of trace minerals in teeth. A selection of teeth of different age groups has been investigated, ranging from the first teeth of infants, through the second teeth of children, to adults to trace the influence of environmental factors on the accumulation of a number of elements in teeth. We found a close link between elements detected in tooth fillings and toothpastes with those present in teeth.

Software and Algorithms for Biomedical Image Data Processing and Visualization

NASA Technical Reports Server (NTRS)

Talukder, Ashit; Lambert, James; Lam, Raymond

2004-01-01

A new software equipped with novel image processing algorithms and graphical-user-interface (GUI) tools has been designed for automated analysis and processing of large amounts of biomedical image data. The software, called PlaqTrak, has been specifically used for analysis of plaque on teeth of patients. New algorithms have been developed and implemented to segment teeth of interest from surrounding gum, and a real-time image-based morphing procedure is used to automatically overlay a grid onto each segmented tooth. Pattern recognition methods are used to classify plaque from surrounding gum and enamel, while ignoring glare effects due to the reflection of camera light and ambient light from enamel regions. The PlaqTrak system integrates these components into a single software suite with an easy-to-use GUI (see Figure 1) that allows users to do an end-to-end run of a patient s record, including tooth segmentation of all teeth, grid morphing of each segmented tooth, and plaque classification of each tooth image. The automated and accurate processing of the captured images to segment each tooth [see Figure 2(a)] and then detect plaque on a tooth-by-tooth basis is a critical component of the PlaqTrak system to do clinical trials and analysis with minimal human intervention. These features offer distinct advantages over other competing systems that analyze groups of teeth or synthetic teeth. PlaqTrak divides each segmented tooth into eight regions using an advanced graphics morphing procedure [see results on a chipped tooth in Figure 2(b)], and a pattern recognition classifier is then used to locate plaque [red regions in Figure 2(d)] and enamel regions. The morphing allows analysis within regions of teeth, thereby facilitating detailed statistical analysis such as the amount of plaque present on the biting surfaces on teeth. This software system is applicable to a host of biomedical applications, such as cell analysis and life detection, or robotic applications, such as product inspection or assembly of parts in space and industry.

Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy.

PubMed

McGuire, J D; Gorski, J P; Dusevich, V; Wang, Y; Walker, M P

2014-10-01

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy. © International & American Associations for Dental Research.

Type IV Collagen is a Novel DEJ Biomarker that is Reduced by Radiotherapy

PubMed Central

McGuire, J.D.; Gorski, J.P.; Dusevich, V.; Wang, Y.; Walker, M.P.

2014-01-01

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy – teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy. PMID:25146181

Bovine teeth as a novel matrix for the control of the food chain: liquid chromatography-tandem mass spectrometry detection of treatments with prednisolone, dexamethasone, estradiol, nandrolone and seven β2-agonists.

PubMed

Chiesa, Luca Maria; Nobile, Maria; Panseri, Sara; Biolatti, Bartolomeo; Cannizzo, Francesca Tiziana; Pavlovic, Radmila; Arioli, Francesco

2017-01-01

Veterinary drugs usually have rapid clearance rates in the liver and kidney, hampering their detection in conventional matrices such as the liver or urine. Pharmacological principles such as esterification may be applied to facilitate the administration of veterinary drugs and increase drug half-life. Prednisolone, whose therapeutic administration is regulated for food producing animals in the EU, is available in its acetate form as well as nandrolone, a banned anabolic steroid, which may be obtained as nandrolone phenylpropionate and estradiol as a benzoyl ester. While the distribution and accumulation of lipophilic and hydrophilic substances in human teeth have been well documented, studies on residues in bovine teeth are lacking. We hypothesised that analysis of bovine teeth could be used to detect both regulated and banned veterinary drugs. Steroids may be illegally used as growth promoters in food producing animals, alone or combined with β2-agonists; therefore, we developed, and validated, in accordance with the Commission Decision 2002/657/EC, two analytical confirmatory LC-MS/MS methods to detect these classes of compounds following a unique liquid extraction procedure. Finally, we analysed teeth from three male Friesian veal calves treated with intramuscular estradiol benzoate, oral prednisolone acetate or intramuscular nandrolone phenylpropionate in combination with oral ractopamine, respectively, and from seven bovines from the food chain. Teeth from treated animals were positive for their respective drugs, with the exception of nandrolone phenylpropionate. One sample from a food chain bovine was positive for isoxsuprine, one of the seven β2-agonists studied. Non-esterified forms of the steroids were not found. These results demonstrate that bovine teeth are a suitable matrix for the determination of pseudoendogenous substances or illicit administration of veterinary drugs.

Impact of birth characteristics, breast feeding and vital statistics on the eruption of primary teeth among healthy infants in Saudi Arabia: an observational study.

PubMed

Alnemer, Kholoud Abdullah; Pani, Sharat Chandra; Althubaiti, Alaa M; Bawazeer, Manal

2017-12-15

This study aimed to explore the impact of gender, birth weight, maternal age, type of delivery, gestational age and feeding practices on the eruption of teeth in children with no underlying medical conditions or developmental defects in their first year of life. A cross-sectional observational study design was used. A primary healthcare setting in Riyadh, Saudi Arabia. All children in their first year of life attending a vaccination clinic (n=422) were included in the study. Infants with chronic childhood illnesses, those who were below the 5th percentile in height or weight, infants with congenital birth defects and chronic illnesses, infants who were born preterm and low birth weight infants were excluded from the study. The type of delivery, birth weight, age of mother, height and weight percentile for age (as plotted on the WHO growth chart for infants) and feeding practices were recorded by the examiner, and this was followed by a clinical examination to determine the presence or absence of each tooth. Regression models were developed to determine the effect of the different variables on the presence of primary teeth. There was a significant association between the weight percentile of the child (adjusted for age) and the number of erupted primary teeth, suggesting that heavier children have an earlier eruption of teeth. No association was observed between birth weight, height percentile for age or maternal age at the time of birth and the number of erupted primary teeth. Children who were exclusively breast fed were significantly more likely to have an erupted first primary tooth earlier than non-breastfed group. Breast feeding and the weight of the child may have an influence on the eruption of primary teeth in the first year of life. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The prognosis of root canal therapy: a 10-year retrospective cohort study on 411 patients with 1175 endodontically treated teeth.

PubMed

Fonzar, Federica; Fonzar, Alberto; Buttolo, Piercarlo; Worthington, Helen V; Esposito, Marco

2009-01-01

To evaluate the 10-year prognosis of consecutively endodontically treated or retreated teeth and to investigate some of the prognostic factors which could predict the long-term outcome of endodontic therapy. This retrospective cohort study included any patient who had endodontically treated or retreated teeth from 1986 to 1998 by a single operator in a private practice. Outcome measures were clinical and radiographic success assessed by the operator, radiographic success assessed by an independent outcome assessor and complications evaluated 10 years after treatment. Descriptive statistics, life table, Kaplan-Meier and Cox regression analyses for success were fitted. A total of 411 patients with 1175 endodontically treated teeth were identified. Ten years after treatment 102 patients (24.8%) with 223 (19.0%) teeth were lost at the follow-up. The number of teeth that were originally treated and retreated were 704 and 471, respectively. Thirty-two teeth (2.7%) had one complication, which was successfully treated. A total of 988 (84.1%) teeth were considered a complete success, 46 (3.9%) a partial success, 52 (4.4%) a partial failure and 68 (5.8%) had to be extracted according to the treating clinician. For 21 teeth (1.8%) there was no follow-up information. The radiographic healing of 1086 teeth was evaluated by an independent assessor: 980 (90.2%) showed complete healing, 52 (4.8%) improvement, and 54 (5.0%) no change or worsening. The life-table analysis showed 93% of teeth surviving at 10 years after endodontic treatment. There were no differences for survival rates between teeth treated for the first time and those that were retreated (Kaplan-Meier). Teeth retreated because of symptoms or for a periapical/lateral radiolucency were more likely to fail. Approximately 7% of endodontically treated teeth were extracted 10 years after treatment. Symptoms and radiolucency of teeth needing retreatment may be important predictors for failure.

Arresting rampant dental caries with silver diamine fluoride in a young teenager suffering from chronic oral graft versus host disease post-bone marrow transplantation: a case report.

PubMed

Chu, Chun-Hung; Lee, Angeline Hui-Cheng; Zheng, Liwu; Mei, May Lei; Chan, Godfrey Chi-Fung

2014-01-03

Rampant caries is an advanced and severe dental disease that affects multiple teeth. This case describes the management of rampant caries in a young teenager suffering from chronic oral graft versus host disease after allogeneic bone marrow transplantation. A 14-year-old Chinese boy suffering from β-thalassemia major was referred to the dental clinic for the management of rampant dental caries. An oral examination revealed pale conjunctiva, bruising of lips, and depapillation of tongue indicating an underlying condition of anemia. The poor oral condition due to topical and systemic immunosuppressants was seriously aggravated, and rampant caries developed rapidly, affecting all newly erupted, permanent teeth. The teeth were hypersensitive and halitosis was apparent. Strategies for oral health education and diet modification were given to the patient. Xylitol chewing gum was used to stimulate saliva flow to promote remineralization of teeth. Silver diamine fluoride was topically applied to arrest rampant caries and to relieve pain from hypersensitivity. Carious teeth with pulpal involvement were endodontically treated. Stainless steel crowns were provided on molars to restore chewing function, and polycarbonate crowns were placed on premolars, upper canines and incisors. This case report demonstrates success in treating a young teenager with severe rampant dental decay by contemporary caries control and preventive strategy.

The evaluation of endodontic flare-ups and their relationship to various risk factors.

PubMed

Onay, Emel Olga; Ungor, Mete; Yazici, A Canan

2015-11-14

To evaluate the incidence of flare-ups and identify the risk factors including age, gender, tooth type, number of root canals, initial diagnosis, the type of irrigation regimen, treatment modality and the number of visits, in patients who received root canal treatment from January 2002 to January 2008. Records of 1819 teeth belonging to 1410 patients treated by 1 endodontics specialist during 6-year period were kept. Patient, tooth, and treatment characteristics were evaluated and the relationships between these characteristics and flare-ups were studied. Statistical analysis was carried out by using Pearson Chi-square test, Fisher's Exact test, and Binary Logistic regression analyses. The incidence of flare-ups was 59 (3.2 %) out of 1819 teeth that received endodontic therapy. Pulpal necrosis without periapical pathosis was the most common indication for flare-up (6 %) (p < 0.01). Teeth undergoing multiple visits had a higher risk of developing flare-ups compared to those with single appointments (OR: 3.14, CI: 1.414-7.009, p < 0.01). There were also no statistically significant differences in the incidence of flare-ups regarding to age, gender, tooth type, number of root canals, treatment modality, and the irrigation solutions that used during the treatment. The incidence of flare-up is minimal when teeth are treated in one visit. Absence of a periapical lesion in necrotic teeth is a significant risk factor for flare-ups.

Effects of ultrasonic dental scaling on pulp vitality in dogs: an experimental study.

PubMed

Vérez-Fraguela, J L; Vives Vallés, M A; Ezquerra Calvo, L J

2000-06-01

We investigated whether dental pulpal damage is produced as a result of the application of an ultrasonic scaler commonly used in clinical veterinary dentistry. Using methods developed in preliminary studies, we examined six dogs. The radiographic thickness of the dentin and pulp cavity was measured. The ultrasonic scaler was applied to maxillary and mandibular premolar teeth for 30, 60, or 90 seconds, without the use of water as a coolant. The temperatures of the room, the pulp canal on untreated incisor teeth, the cheek, the gingival sulcus, and the dentin of the affected teeth were recorded using a probe with a thermistor attached to a resistivity meter and inserted in the dentin to a depth of 1 mm. Two weeks following scaling, the teeth were extracted for microscopic examination. In another dog serving as a control, the temperature of the dentin was increased to between 45 degrees C (113 degrees F) and 47 degrees C (117 degrees F) and the premolar teeth were removed for microscopic examination 15 days later. We concluded that the application of an uncooled ultrasonic scaler for 90 seconds did not increase the temperature of the dentin. However, damage comparable with acute pulpitis resulted as a consequence of the ultrasonic effect, similar to the effects produced by the 45-47 degrees C heat applied in the control animal.

Development of horizontal tooth wear in maxillary anterior teeth from five to 18 years of age.

PubMed

Nyström, M; Könönen, M; Alaluusua, S; Evälahti, M; Vartiovaara, J

1990-11-01

Sizes of horizontal wear facets of maxillary anterior teeth were studied longitudinally from the primary dentition at age five to the young adult dentition at the age of 18 years. By a planimetric method, we calculated the wear areas on dental casts taken at the ages of five, ten, 14, and 18 years from the dentition of 39 healthy, orthodontically untreated subjects with good morphological occlusion. For young adults, we also studied the association between the amount of wear and reported parafunctions, maximal bite force, salivary buffer capacity, salivary flow rate, and some cephalometric variables. Size of wear facets on all anterior teeth increased with age. Significant correlations were found between the total wear areas of the six anterior primary teeth at five years of age and those of their permanent successors at age 14 (r = 0.44) and 18 (r = 0.39). For an individual, tooth wear at five years of age was, however, of low predictive value for tooth wear in young adulthood, whereas tooth wear at 14 years of age predicted it well (r = 0.89). Highest correlations between tooth wear and background factors at 18 years of age were found for maximal anterior bite force (r = 0.44) and for the size of the gonial angle (r = -0.31). Wear of anterior teeth was not associated with reported parafunctions in young adulthood.

Impacted Wisdom Teeth

MedlinePlus

Impacted wisdom teeth Overview Impacted wisdom teeth are third molars at the back of the mouth that don' ... with an impacted wisdom tooth. Causes Wisdom teeth (third molars) become impacted because they don't have enough ...

Estimation of age from teeth by amino acid racemization: influence of fixative.

PubMed

Ohtani, S; Ohhira, H; Watanabe, A; Ogasawara, A; Sugimoto, H

1997-01-01

To determine the age of a subject from teeth accurately utilizing the racemization rates of amino acids, standard samples of the same tooth species from the same jaw are necessary as controls, as well as data for identification. However, standard teeth are generally stored in fixatives such as ethanol and formalin. We investigated and compared the degree of progression of racemization of dentinal aspartic acid in teeth stored in 95% ethanol, 10% formalin, or 10% neutral formalin fixatives. The racemization rate of dentinal aspartic acid in teeth stored in 10% neutral formalin was the highest, followed by that for teeth stored in 10% formalin then that for teeth stored in 95% ethanol. Teeth stored in these fixatives at 15 degrees C showed almost no progression of racemization. The racemization ratio (D/L ratio) in teeth extracted 10 years previously was almost unchanged from that at the time of extraction, and allowed an accurate evaluation of the subjects age at tooth extraction.

[Relationship between orthodontics root resorption following experimental tooth movement and the level of dentin sialoph-osphoprotein and dentin sialoprotein in gingival crevicular fluid].

PubMed

Zuo, Zhi-Gang; Hu, Min; Jiang, Huan; Tian, Li

2011-06-01

To investigate the relationship of expression of dentin sialoph-osphoprotein (DSPP) and dentin sialoprotein (DSP) in gingival crevicular fluid (GCF) with root resorption following experimental tooth movement in rats. 36 Wistar rats were divided into 3 groups on average randomly: Control group, light force group and heavy force group. The experimental teeth were drawn-off mesially by the force of 0.392 N in light force group and 0.98 N in heavy force group, with both of the maxillary central incisors as the tooth of anchorage. At the 7th day, the gingival crevicular fluid of rats were collected; the histological slices were made, including the experimental tooth and periodontal tissue; the tissues was stained with hematoxylin-eosin (HE) staining and tartrate resistant acid phosphatase (TRAP) staining to observe the histological changes of the root resorption of rats. Then the expression of DSPP and DSP were assayed by using biochemistry techniques of Western blot. Histological observation: There was not root resorption in control group. Neither root resorption nor cementoclast was observed in light force group. And in heavy force group visible root resorption came out in pressure zone. Western blot results: There was expression of DSPP and no DSP in control group, and there was the expression of DSPP and DSP in both light force group and heavy force group. The result of statistical analysis showed that there were significant differences in the expression of DSPP and DSP among three groups. The highest one was heavy force group, followed by the light force group and control group with the least amount of proteins. There is the expression of DSPP and DSP in gingival crevicular fluid following experimental tooth movement with root resorption.

Effects of incisor extraction on jaw and tongue motor representations within face sensorimotor cortex of adult rats.

PubMed

Avivi-Arber, Limor; Lee, Jye-Chang; Sessle, Barry J

2010-04-01

Loss of teeth is associated with changes in somatosensory inputs and altered patterns of mastication, but it is unclear whether tooth loss is associated with changes in motor representations within face sensorimotor cortex of rats. We used intracortical microstimulation (ICMS) and recordings of cortically evoked muscle electromyographic (EMG) activities to test whether changes occur in the ICMS-defined motor representations of the left and right jaw muscles [masseter, anterior digastric (LAD, RAD)] and tongue muscle [genioglossus (GG)] within the cytoarchitectonically defined face primary motor cortex (face-M1) and adjacent face primary somatosensory cortex (face-S1) 1 week following extraction of the right mandibular incisor in anesthetized (ketamine-HCl) adult male Sprague-Dawley rats. Under local and general anesthesia, an "extraction" group (n = 8) received mucoalveolar bone surgery and extraction of the mandibular right incisor. A "sham-extraction" group (n = 6) received surgery with no extraction. A "naive" group (n = 6) had neither surgery nor extraction. Data were compared by using mixed-model repeated-measures ANOVA. Dental extraction was associated with a significantly increased number of sites within face-M1 and face-S1 from which ICMS evoked RAD EMG activities, a lateral shift of the RAD and LAD centers of gravity within face-M1, shorter onset latencies of ICMS-evoked GG activities within face-M1 and face-S1, and an increased number of sites within face-M1 from which ICMS simultaneously evoked RAD and GG activities. Our novel findings suggest that dental extraction may be associated with significant neuroplastic changes within the rat's face-M1 and adjacent face-S1 that may be related to the animal's ability to adapt to the altered oral state. (c) 2009 Wiley-Liss, Inc.

The effects of blocking N/OFQ receptors on orofacial pain following experimental tooth movement in rats.

PubMed

Shan, Di; He, Yuwei; Long, Hu; Zhou, Yang; Liu, He; Xu, Rui; Huang, Renhuan; Lai, Wenli

2016-11-01

The aim of this study was to determine the effects of nociceptin/orphanin FQ peptide receptor (N/OFQ receptor) antagonist on orofacial pain induced by experimental tooth movement in rats. A total of 36 male Sprague-Dawley rats weighing 200-300 g were divided into six groups: a control group, force group, force+saline intraperitoneal group, force+saline periodontal group, force+UFP-101 ([Nphe¹,Arg¹⁴,Lys¹⁵]N/OFQ-NH ₂ antagonist for N/OFQ receptor) intraperitoneal group, and force+UFP-1 01 periodontal group. Closed coil springs were ligated between the upper incisors and first molar to exert an orthodontic force (40 g) between the teeth. Injectable administration dosages were 30 μl saline or 30 μl saline containing 0.03 mg/kg UFP-1 01. Following the injections, orofacial pain levels were assessed through directed face grooming (mouth wiping). Statistical analyses were performed in SPSS 17.0 (Statistical Package for the Social Sciences) and p values less than 0.05 were considered as statistically significant. Orofacial pain levels were significantly higher in the force group than in the control group. Orofacial pain levels differed significantly between the force)group, force+saline periodontal group and force+UFP-101 periodontal group, but were similar between the control group, force+UFP-101 intraperitoneal group and force+saline intraperitoneal group. Moreover, orofacial pain levels did not differ between the force group, force+saline intraperitoneal group and force+UFP-1 01 intraperitoneal group. Periodontal, but not intraperitoneal, administration of UFP-101 could alleviate orofacial pain induced by experimental tooth movement in rats, suggesting that periodontal N/OFQ receptors participate in orofacial pain induced by experimental tooth movement.

Human dental pulp stem cells transplantation combined with treadmill training in rats after traumatic spinal cord injury

PubMed Central

Nicola, F.C.; Rodrigues, L.P.; Crestani, T.; Quintiliano, K.; Sanches, E.F.; Willborn, S.; Aristimunha, D.; Boisserand, L.; Pranke, P.; Netto, C.A.

2016-01-01

Spinal cord injury (SCI) is a disabling condition resulting in deficits of sensory and motor functions, and has no effective treatment. Considering that protocols with stem cell transplantation and treadmill training have shown promising results, the present study evaluated the effectiveness of stem cells from human exfoliated deciduous teeth (SHEDs) transplantation combined with treadmill training in rats with experimental spinal cord injury. Fifty-four Wistar rats were spinalized using NYU impactor. The rats were randomly distributed into 5 groups: Sham (laminectomy with no SCI, n=10); SCI (laminectomy followed by SCI, n=12); SHEDs (SCI treated with SHEDs, n=11); TT (SCI treated with treadmill training, n=11); SHEDs+TT (SCI treated with SHEDs and treadmill training; n=10). Treatment with SHEDs alone or in combination with treadmill training promoted functional recovery, reaching scores of 15 and 14, respectively, in the BBB scale, being different from the SCI group, which reached 11. SHEDs treatment was able to reduce the cystic cavity area and glial scar, increase neurofilament. Treadmill training alone had no functional effectiveness or tissue effects. In a second experiment, the SHEDs transplantation reduced the TNF-α levels in the cord tissue measured 6 h after the injury. Contrary to our hypothesis, treadmill training either alone or in combination, caused no functional improvement. However, SHEDs showed to be neuroprotective, by the reduction of TNF-α levels, the cystic cavity and the glial scar associated with the improvement of motor function after SCI. These results provide evidence that grafted SHEDs might be an effective therapy to spinal cord lesions, with possible anti-inflammatory action. PMID:27509306

Human dental pulp stem cells transplantation combined with treadmill training in rats after traumatic spinal cord injury.

PubMed

Nicola, F C; Rodrigues, L P; Crestani, T; Quintiliano, K; Sanches, E F; Willborn, S; Aristimunha, D; Boisserand, L; Pranke, P; Netto, C A

2016-08-08

Spinal cord injury (SCI) is a disabling condition resulting in deficits of sensory and motor functions, and has no effective treatment. Considering that protocols with stem cell transplantation and treadmill training have shown promising results, the present study evaluated the effectiveness of stem cells from human exfoliated deciduous teeth (SHEDs) transplantation combined with treadmill training in rats with experimental spinal cord injury. Fifty-four Wistar rats were spinalized using NYU impactor. The rats were randomly distributed into 5 groups: Sham (laminectomy with no SCI, n=10); SCI (laminectomy followed by SCI, n=12); SHEDs (SCI treated with SHEDs, n=11); TT (SCI treated with treadmill training, n=11); SHEDs+TT (SCI treated with SHEDs and treadmill training; n=10). Treatment with SHEDs alone or in combination with treadmill training promoted functional recovery, reaching scores of 15 and 14, respectively, in the BBB scale, being different from the SCI group, which reached 11. SHEDs treatment was able to reduce the cystic cavity area and glial scar, increase neurofilament. Treadmill training alone had no functional effectiveness or tissue effects. In a second experiment, the SHEDs transplantation reduced the TNF-α levels in the cord tissue measured 6 h after the injury. Contrary to our hypothesis, treadmill training either alone or in combination, caused no functional improvement. However, SHEDs showed to be neuroprotective, by the reduction of TNF-α levels, the cystic cavity and the glial scar associated with the improvement of motor function after SCI. These results provide evidence that grafted SHEDs might be an effective therapy to spinal cord lesions, with possible anti-inflammatory action.

Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy

NASA Astrophysics Data System (ADS)

Porto, Isabel Maria; Saiani, Regina Aparecida; Chan, K. L. Andrew; Kazarian, Sergei G.; Gerlach, Raquel Fernanda; Bachmann, Luciano

2010-09-01

Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45 ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors were removed and prepared for analysis by two FTIR techniques namely, transmission and micro-ATR. For the first technique, the enamel was powdered, whereas in the second case one fluorotic incisor was cut longitudinally for micro-ATR. Using transmission and powdered samples, FTIR showed a higher C-H content in the fluorotic enamel compared with control enamel ( p < 0.05, n = 4 in the flurotic, and n = 5 in the control group). Results from the micro-ATR-FTIR spectroscopic analysis on one longitudinally cut incisor carried out at six points reveal a higher C-H bond content at the surface of the enamel, with values decreasing toward the dentine-enamel junction, and reaching the lowest values at the subsuperficial enamel. These results agree with the morphological data, which indicate that in the rat incisor the fluorotic lesion is superficial, rather than subsuperficial, as in the case of human enamel. The results also suggest that the increased C-H bond content may extend toward the more basal enamel (intraosseous), indicating that fluorotic enamel may intrinsically contain more protein. Finally, particularly when coupled to ATR, FTIR is a suitable tool to study the rat incisor enamel, which is a largely used model of normal and abnormal amelogenesis. Further studies along this line may definitely answer some questions regarding protein content in fluorotic enamel as well as their origin.

Teeth Injuries (For Parents)

MedlinePlus

... Videos for Educators Search English Español First Aid: Teeth Injuries KidsHealth / For Parents / First Aid: Teeth Injuries ... or young child injures the gums or baby teeth: Apply pressure to the area (if it's bleeding) ...

Partial tooth gear bearings

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2010-01-01

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Management of a rare case of idiopathic multiple unerupted impacted permanent teeth in an adult female patient

PubMed Central

Shetty, Karunakar; Kumar, Mahesh; Amanna, Susan; Sridharan, Srirangarajan; Reddy, Satyanarayan

2016-01-01

This clinical case report describes the multi-disciplinary approach in the management of an unusual presentation of idiopathic multiple unerupted impacted permanent teeth in a 20-year-old female patient. The case was unique in that, not only were there multiple missing permanent teeth, but also over retained deciduous teeth and attrited existing permanent teeth with loss of vertical dimension of occlusion. Since the patient was young, it was decided to retain all the erupted permanent teeth and extract the infected deciduous teeth with the objective of fabricating overlay complete dentures. This is a simple, reversible and an economical treatment modality, which satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated and, in addition, provides a stable occlusion. PMID:27621553

Comparison of the microhardness of primary and permanent teeth after immersion in two types of carbonated beverages.

PubMed

Haghgou, Hamid R; Haghgoo, Roza; Asdollah, Fatemah Molla

2016-01-01

The consumption of carbonated beverages is one of the etiological factors that cause dental erosion. The purpose of this research was to compare changes in the microhardness of permanent and primary teeth after immersion in two types of carbonated beverages. This investigation was done on 30 healthy permanent molars and 30 healthy primary canines. Each group of primary and permanent teeth was subdivided into three groups of 10 teeth. The teeth was immersed in 40 ml of each of the three beverages for 5 min. One subgroup was immersed in water (as a control). The next was immersed in Lemon Delster and the last subgroup was immersed in Coca-Cola. The microhardness of enamel was measured using the Vickers method before and after immersion. Finally, the data was analyzed by paired t-test, one-way analysis of variance, and t-test. Microhardness reduction in the primary teeth was significant in both the Lemon Delster and Coca-Cola groups (P < 0.05). This reduction was also statistically significant in the permanent teeth (P < 0.05). A comparison of the enamel changes in the primary teeth with permanent teeth after immersion in both beverages showed a greater microhardness reduction in the primary teeth in both the experimental groups. Coca-Cola and Lemon Delster caused a significant reduction of microhardness in tooth enamel. This reduction was greater in primary teeth than in permanent teeth, and was also greater after immersion in Coca-Cola than after immersion in Lemon Delster.

Replantation of 45 avulsed permanent teeth: a 1-year follow-up study.

PubMed

Chappuis, Vivianne; von Arx, Thomas

2005-10-01

Thirty-four patients with 45 avulsed and replanted permanent teeth were followed for 1 year. All teeth were soaked in tetracycline before replantation. In addition, enamel matrix derivative was used in teeth with dry storage times exceeding 30 min. Splinting was carried out with a non-rigid titanium splint and was limited to 7-10 days. Within that period, root canal treatment was begun in all teeth with a closed apex, whereas teeth with an open apex and ideal post-traumatic storage were not instrumented. All patients were given tetracycline systematically for 10 days. The survival rate of replanted avulsed permanent teeth was 95.6% at the 1-year follow-up. In 82.2%, root canal treatment was performed. Pulp survival was never observed, but three teeth had pulp canal obliteration. Normal periodontal healing was observed in 57.7% of teeth; 42.3% of teeth showed external root resorption (28.9% replacement resorption, 6.7% infection-related resorption, 6.7% surface resorption). The occurrence of replacement resorption correlated with the period of extraoral dry storage. Compared with other clinical studies on avulsed and replanted teeth, the present study reports a higher percentage of periodontal healing. The favorable treatment outcome may be associated with a strict protocol to enforce endodontic treatment, the use of topical and systemic tetracycline, and the relatively high number of ideally stored teeth following avulsion. In contrast, the present study has a follow-up period limited to 1 year.

Micromorphological differentiation of left and right stridulatory apparatus in crickets (Orthoptera: Gryllidae).

PubMed

Li, Xiaoqiang; Zhang, Xue; Luo, Wenqi; Wang, Yinliang; Ren, Bingzhong

2016-06-24

The present study compared micromorphological differentiation of stridulatory apparatus between the functional right tegmen and non-functional left tegmen, analyzed under scanning electron microscope (SEM), among eight Gryllidae species. The results showed that the main differences were found on the length and shape of files and teeth. The length of stridulatory file and teeth number were lower on the left stridulatory apparatus than that on right stridulatory apparatus in all species. However, the ratio between the length of stridulatory teeth and the interval of stridulatory teeth was significantly higher on the left stridulatory apparatus than that on right stridulatory apparatus in Dianemobius fascipes, Polionemobius taprobanensis, Pteronemobius gifuensis, Teleogryllus occipitalis and Oecanthus longicauda. In addition, the length of stridulatory teeth was positively related to number of stridulatory teeth, however, the interval of stridulatory teeth was negatively related to the ratio between the length of stridulatory teeth and the interval of stridulatory teeth for left and right stridulatory apparatus. Our result illustrated that the length of left and right stridulatory file and teeth length could be an effective character to distinguish species. Left stridulatory apparatus was not entirely degraded than right stridulatory apparatus.

Dental Anomalies in Permanent Teeth after Trauma in Primary Dentition.

PubMed

Bardellini, Elena; Amadori, Francesca; Pasini, Stefania; Majorana, Alessandra

This retrospective study aims to evaluate the prevalence of dental anomalies in permanent teeth as a result of a trauma concerning the predecessor primary teeth. A total of 241 records of children (118 males and 123 females, mean age 3.62 ± 1.40) affected by trauma on primary teeth were analyzed. All patients were recalled to evaluate the status of the permanent successor teeth by clinical and radiographic investigations. Out of 241 patients, 106 patients (for a total of 179 traumatized primary teeth) presented at the recall. Dental anomalies on successor permanent teeth were detected in 21 patients (19.8%), for a total of 26 teeth (14.5%) and 28 anomalies. Anomalies of the eruptive process were the most observed disturbances (60.7%), followed by enamel hypoplasia (25%) and white spots (14.3%). A higher percentage of anomalies on permanent teeth was observed when trauma occurred at an age less than 36 months (38.5% of cases). Intrusive and extrusive luxation were related with the most cases of clinical disturbances in the successor permanent teeth. The results of this study highlight the risk of dental anomalies after a trauma in primary dentition, especially in early-aged children and in case of intrusive luxation.

Success of Maxillary Alveolar Defect Repair in Rats Using Osteoblast-Differentiated Human Deciduous Dental Pulp Stem Cells.

PubMed

Jahanbin, Arezoo; Rashed, Roozbeh; Alamdari, Daryoush Hamidi; Koohestanian, Niloufar; Ezzati, Atefeh; Kazemian, Mojgan; Saghafi, Shadi; Raisolsadat, Mohammad Ali

2016-04-01

The use of cell-based therapies represents one of the most advanced methods for enhancing the regenerative response in craniofacial abnormalities. The main aim of this study was to evaluate the regenerative potential of human dental pulp stem cells, isolated from deciduous teeth, for reconstructing maxillary alveolar defects in Wistar rats. Human deciduous dental pulp stem cells were isolated and stimulated to differentiate into osteoblasts in culture media. Maxillary alveolar defects were created in 60 Wistar rats by a surgical procedure. Then, on the basis of the type of graft used to repair the bone defect, the rats were divided into 6 equal groups: groups 1 and 2, transplantation of iliac bone graft; groups 3 and 4, transplantation of stem cells derived from deciduous dental pulp in addition to collagen matrix; groups 5 and 6, transplantation of just collagen matrix. Then, fetal bone formation, granulation tissue, fibrous tissue, and inflammatory tissue were evaluated by hematoxylin-eosin staining at 1 month (groups 1, 3, and 5) and 2 months (groups 2, 4, and 6) after surgery, and data were analyzed and compared using the Fisher exact test. Maximum fetal bone formation occurred in group 2, in which iliac bone graft was inserted into the defect area for 2 months; there also were significant differences among the groups for bone formation (P = .009). In the 1-month groups, there were no significant differences between the control and stem cell-plus-scaffold groups. There were significant differences between the 2-month groups for fetal bone formation only between the control and scaffold groups (P = .026). The study showed that human dental pulp stem cells are an additional cell resource for repairing maxillary alveolar defects in rats and constitute a promising model for reconstruction of human maxillary alveolar defects in patients with cleft lip and palate. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Co-exposure to methylmercury and inorganic arsenic in baby rice cereals and rice-containing teething biscuits.

PubMed

Rothenberg, Sarah E; Jackson, Brian P; Carly McCalla, G; Donohue, Alexis; Emmons, Alison M

2017-11-01

Rice is an important dietary source for methylmercury (MeHg), a potent neurotoxin, and inorganic arsenic (As), a human carcinogen. Rice baby cereals are a dietary source of inorganic As; however, less is known concerning MeHg concentrations in rice baby cereals and rice teething biscuits. MeHg concentrations were measured in 36 rice baby cereals, eight rice teething biscuits, and four baby cereals manufactured with oats/wheat (n = 48 total). Arsenic (As) species, including inorganic As, were determined in rice baby cereals and rice teething biscuits (n = 44/48), while total As was determined in all products (n = 48). Rice baby cereals and rice teething biscuits were on average 61 and 92 times higher in MeHg, respectively, and 9.4 and 4.7 times higher in total As, respectively, compared to wheat/oat baby cereals. For a 15-g serving of rice baby cereal, average MeHg intake was 0.0092μgday -1 (range: 0.0013-0.034μgday -1 ), while average inorganic As intake was 1.3μgday -1 (range: 0.37-2.3μgday -1 ). Inorganic As concentrations in two brands of rice baby cereal (n = 12/36 boxes of rice cereal) exceeded 100ng/g, the proposed action level from the U.S. Food and Drug Administration. Log 10 MeHg and inorganic As concentrations in rice baby cereals were strongly, positively correlated (Pearson's rho = 0.60, p < 0.001, n = 36). Rice-containing baby cereals and teething biscuits were a dietary source of both MeHg and inorganic As. Studies concerning the cumulative impacts of MeHg and inorganic As on offspring development are warranted. Copyright © 2017 Elsevier Inc. All rights reserved.

Cumulative costs for the prosthetic reconstructions and maintenance in young adult patients with birth defects affecting the formation of teeth.

PubMed

Incici, Erol; Matuliene, Giedre; Hüsler, Jürg; Salvi, Giovanni E; Pjetursson, Bjarni; Brägger, Urs

2009-07-01

To assess retrospectively the cumulative costs for the long-term oral rehabilitation of patients with birth defects affecting the development of teeth. Patients with birth defects who had received fixed reconstructions on teeth and/or implants > or =5 years ago were asked to participate in a comprehensive clinical, radiographic and economic evaluation. From the 45 patients included, 18 were cases with a cleft lip and palate, five had amelogenesis/dentinogenesis imperfecta and 22 were cases with hypodontia/oligodontia. The initial costs for the first oral rehabilitation (before the age of 20) had been covered by the Swiss Insurance for Disability. The costs for the initial rehabilitation of the 45 cases amounted to 407,584 CHF (39% for laboratory fees). Linear regression analyses for the initial treatment costs per replaced tooth revealed the formula 731 CHF+(811 CHF x units) on teeth and 3369 CHF+(1183 CHF x units) for reconstructions on implants (P<.001). Fifty-eight percent of the patients with tooth-supported reconstructions remained free from failures/complications (median observation 15.7 years). Forty-seven percent of the patients with implant-supported reconstructions remained free from failures/complications (median observation 8 years). The long-term cumulative treatment costs for implant cases, however, were not statistically significantly different compared with cases reconstructed with tooth-supported fixed reconstructions. Twenty-seven percent of the initial treatment costs were needed to cover supportive periodontal therapy as well as the treatment of technical/biological complications and failures. Insurance companies should accept to cover implant-supported reconstructions because there is no need to prepare healthy teeth, fewer tooth units need to be replaced and the cumulative long-term costs seem to be similar compared with cases restored on teeth.

Comparison of endotoxin levels found in primary and secondary endodontic infections.

PubMed

Gomes, Brenda P F A; Endo, Marcos S; Martinho, Frederico C

2012-08-01

This clinical study was conducted to compare the levels of endotoxins (lipopolysaccharides [LPSs]) found in primary and secondary endodontic infections with apical periodontitis by correlating LPS contents with clinical/radiographic findings. In addition, the presence of target gram-negative anaerobic bacteria was also investigated. Samples were taken from 15 root canals with primary infections and 15 with secondary infections by using paper points. The limulus amebocyte lysate assay was used to quantify endotoxins, and the polymerase chain reaction technique (16S rDNA) was used for bacterial investigation. Endotoxins were detected in 100% of the root canal samples collected from primary (15/15) and secondary (15/15) infections with median values of 7.49 EU/mL and 3.96 EU/mL, respectively (P < .05). The median value of endotoxins found in the presence of clinical symptoms was significantly higher than in asymptomatic teeth with primary infections (P < .05). A positive correlation was found between endotoxin contents and a larger size of the radiolucent area (>3 mm) (P < .05). Prevotella nigrescens (10/15, 4/15), Fusobacterium nucleatum (5/15, 1/15), Treponema denticola (3/15, 1/15), and Treponema socranskii (5/15, 1/15) were detected in teeth with primary and secondary infections, respectively. P. endodontalis was present only in teeth with primary infections (5/15). Teeth with primary endodontic infections had higher contents of endotoxins and a more complex gram-negative bacterial community than teeth with secondary infections. Moreover, the levels of endotoxins were related to the severity of bone destruction in periapical tissues as well as the development of clinical features in teeth with primary infections. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Inherited retarded eruption in the permanent dentition.

PubMed

Rasmussen, P; Kotsaki, A

1997-01-01

The term retarded eruption, may be used in cases where eruption is inhibited, causing an interruption in the coordination of tooth formation and tooth eruption. The phenomenon may be local or general, and several etiological factors for retarded eruption have been listed, comprising a lack of space, ankylosis, cysts, supernumerary teeth, hormone and vitamin deficiencies and several developmental disturbances and syndromes. The present paper describes several cases of retarded eruption where no factors other than inheritance have been evident. So far 14 cases have been evaluated, 9 boys and 5 girls. In addition several cases have been registered among parents and grandparents of the probands. Typical features are: retarded eruption, defined as more than 3 SD beyond mean eruption figures, comprises all teeth in the permanent dentition, and in 5 cases also second primary molars. The chronology of tooth formation are within normal limits. Consequently the teeth finish development still laying deeply buried in the jaws, often in aberrant positions and with curves or hooks on the roots. When the teeth finally get the "signal" for eruption, 5-15 years beyond normal eruption time, they move rather quickly into right positions, despite the long eruption paths and the hooked roots. Permanent teeth without, as well as with predecessors, are affected. Extraction of predecessors does not seem to provoke eruption. The main features in management are to take care of the primary teeth, to improve-esthetics, and offer surgery and orthodontics when needed. Analyses of pedigrees indicates that the genetic transmittance may be autosomal dominant as both sexes are affected, about half of the siblings show the trait, and the trait shows continuity through generations.

Evaluation of fracture resistance in simulated immature teeth using Resilon and Ribbond as root reinforcements--an in vitro study.

PubMed

Hemalatha, Hiremath; Sandeep, Metgud; Kulkarni, Sadanand; Yakub, Shoeb Sheikh

2009-08-01

To compare the reinforcement and strengthening ability of resilon, gutta-percha, and ribbond in endodontically treated roots of immature teeth. Sixty five freshly extracted human maxillary anterior teeth were prepared with a Peeso no. 6 to simulate immature teeth (Cvek's stage 3 root development). After instrumentation, each root was irrigated with sodium hypochlorite and with ethylene diamino tetra acetic acid to remove the smear layer. To simulate single visit apexification technique a 4-5 mm white Pro Root mineral trioxide aggregate plug was placed apically using schilder carrier. The teeth were divided into three experimental groups and one control group. Group I--control group (root canals instrumented but not filled); Group II--backfilled with thermoplastisized gutta-percha using AH plus sealer; Group III--reinforced with Resilon using epiphany sealer; Group IV--reinforced with Ribbond fibers using Panavia F luting cement. A Universal Testing Machine was used to apply a load, at the level of the lingual cementoenamel junction with a chisel-shaped tip The peak load to fracture was recorded and statistical analysis was completed using student's t-test. Values of peak load to fracture were 1320.8, 1604.88, 1620, and 1851 newtons for Group I to Group IV respectively. The results of student's t-test, revealed no significant difference (P > 0.05,) between Group II and Group III. Comparison between Group IV and Group III and between Group IV and Group II revealed highly significant difference (P > 0.001). Teeth reinforced with Ribbond fibers using Panavia F luting cement showed the highest resistance to fracture. Resilon could not strengthen the roots and showed no statistically significant difference when compared with thermoplastisized gutta-percha in reinforcing immature tooth when tested with universal testing machine in an experimental model of immature tooth.

Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation: A Preliminary Assessment of Real-Time Cephalometry as Part of the Computer-Assisted Planning and Execution Workstation for Craniomaxillofacial Surgery.

PubMed

Murphy, Ryan J; Basafa, Ehsan; Hashemi, Sepehr; Grant, Gerald T; Liacouras, Peter; Susarla, Srinivas M; Otake, Yoshito; Santiago, Gabriel; Armand, Mehran; Gordon, Chad R

2015-08-01

The aesthetic and functional outcomes surrounding Le Fort-based, face-jaw-teeth transplantation have been suboptimal, often leading to posttransplant class II/III skeletal profiles, palatal defects, and "hybrid malocclusion." Therefore, a novel technology-real-time cephalometry-was developed to provide the surgical team instantaneous, intraoperative knowledge of three-dimensional dentoskeletal parameters. Mock face-jaw-teeth transplantation operations were performed on plastic and cadaveric human donor/recipient pairs (n = 2). Preoperatively, cephalometric landmarks were identified on donor/recipient skeletons using segmented computed tomographic scans. The computer-assisted planning and execution workstation tracked the position of the donor face-jaw-teeth segment in real time during the placement/inset onto recipient, reporting pertinent hybrid cephalometric parameters from any movement of donor tissue. The intraoperative data measured through real-time cephalometry were compared to posttransplant measurements for accuracy assessment. In addition, posttransplant cephalometric relationships were compared to planned outcomes to determine face-jaw-teeth transplantation success. Compared with postoperative data, the real-time cephalometry-calculated intraoperative measurement errors were 1.37 ± 1.11 mm and 0.45 ± 0.28 degrees for the plastic skull and 2.99 ± 2.24 mm and 2.63 ± 1.33 degrees for the human cadaver experiments. These results were comparable to the posttransplant relations to planned outcome (human cadaver experiment, 1.39 ± 1.81 mm and 2.18 ± 1.88 degrees; plastic skull experiment, 1.06 ± 0.63 mm and 0.53 ± 0.39 degrees). Based on this preliminary testing, real-time cephalometry may be a valuable adjunct for adjusting and measuring "hybrid occlusion" in face-jaw-teeth transplantation and other orthognathic surgical procedures.

Cryopreserved Dental Pulp Tissues of Exfoliated Deciduous Teeth Is a Feasible Stem Cell Resource for Regenerative Medicine

PubMed Central

Yamaza, Haruyoshi; Akiyama, Kentaro; Hoshino, Yoshihiro; Song, Guangtai; Kukita, Toshio; Nonaka, Kazuaki; Shi, Songtao; Yamaza, Takayoshi

2012-01-01

Human exfoliated deciduous teeth have been considered to be a promising source for regenerative therapy because they contain unique postnatal stem cells from human exfoliated deciduous teeth (SHED) with self-renewal capacity, multipotency and immunomodulatory function. However preservation technique of deciduous teeth has not been developed. This study aimed to evaluate that cryopreserved dental pulp tissues of human exfoliated deciduous teeth is a retrievable and practical SHED source for cell-based therapy. SHED isolated from the cryopreserved deciduous pulp tissues for over 2 years (25–30 months) (SHED-Cryo) owned similar stem cell properties including clonogenicity, self-renew, stem cell marker expression, multipotency, in vivo tissue regenerative capacity and in vitro immunomodulatory function to SHED isolated from the fresh tissues (SHED-Fresh). To examine the therapeutic efficacy of SHED-Cryo on immune diseases, SHED-Cryo were intravenously transplanted into systemic lupus erythematosus (SLE) model MRL/lpr mice. Systemic SHED-Cryo-transplantation improved SLE-like disorders including short lifespan, elevated autoantibody levels and nephritis-like renal dysfunction. SHED-Cryo amended increased interleukin 17-secreting helper T cells in MRL/lpr mice systemically and locally. SHED-Cryo-transplantation was also able to recover osteoporosis bone reduction in long bones of MRL/lpr mice. Furthermore, SHED-Cryo-mediated tissue engineering induced bone regeneration in critical calvarial bone-defect sites of immunocompromised mice. The therapeutic efficacy of SHED-Cryo transplantation on immune and skeletal disorders was similar to that of SHED-Fresh. These data suggest that cryopreservation of dental pulp tissues of deciduous teeth provide a suitable and desirable approach for stem cell-based immune therapy and tissue engineering in regenerative medicine. PMID:23251621

Management of a child with severe hypodontia in the mixed dentition stage of development.

PubMed

Tong, H J; Tahmassebi, J F

2014-12-01

Severe hypodontia is a condition characterized by developmental absence of six or more teeth and affects 0.14-0.3% of the overall population. Hypodontia can have a marked psychosocial effect and functional implications for a growing child. A 10-year-old girl with a medical history of hypothyroidism and repaired spinal bifida was referred to the Leeds Dental Institute as she was becoming increasingly concerned about her appearance. On clinical examination, the patient had severe wear of her over-retained maxillary primary central incisors, microdontia of mandibular anterior teeth (32, 34, 41, 42, 43), and loss of anterior vertical dimension. Radiographic examination revealed that the patient had 11 missing permanent teeth (14, 13, 12, 11, 21, 22, 23, 24, 31, 35, 44), an ectopic mandibular left canine and taurodontism of the permanent molars. Management of the patient included an intensive preventive programme with placement of fissure sealants; scaling of calculus deposition on microdont teeth; composite resin reconstruction of microdont teeth; fabrication of removable partial overdentures tailored aesthetically to match the patient's age; orthodontic consultation and monitoring for the eruption of ectopic canine and permanent dentition. The patient and her parents reported marked improvement in self-esteem following dental treatment. After 2 years of follow-up, a new pair of dentures were made and designed to allow ease of eruption of the existing permanent dentition. All permanent teeth have erupted. The patient is ready for further assessment and planning for future orthodontic and restorative/implant treatment. This case illustrates the essential role of the paediatric dentist in the management of hypodontia in the mixed dentition stage.

Microscopic study of dental hard tissues in primary teeth with Dentinogenesis Imperfecta Type II: Correlation of 3D imaging using X-ray microtomography and polarising microscopy.

PubMed

Davis, Graham R; Fearne, Janice M; Sabel, Nina; Norén, Jörgen G

2015-07-01

The aim of this study was to examine the histological appearance of dental hard tissues in primary teeth from children with DI using conventional polarised light microscopy and correlate that with 3D imaging using X-ray microtomograpy (XMT) to gain a further understanding of the dentine structure of teeth diagnosed with dentinogenesis imperfecta. Undecalcified sections of primary teeth from patients diagnosed with Dentinogenesis Imperfecta Type II were examined using polarised light microscopy. XMT was employed for 3D-imaging and analysis of the dentine. The polarised light microscopy and XMT revealed tubular structures in the dentine seen as vacuoles coinciding with the path of normal dentinal tubules but not continuous tubules. The size of the tubules was close to that of capillaries. The largest tubular structures had a direction corresponding to where the pulp tissue would have been located during primary dentine formation. The dysfunctional mineralisation of the dentine and obliteration of the pulp evidently leaves blood vessels in the dentine which have in the main been tied off and, in the undecalcified sections, appear as vacuoles. Although from radiographs, the pulp in teeth affected by Dentinogenesis Imperfect type II appears to be completely obliterated, a network of interconnected vessels may remain. The presence of large dentinal tubules and blood vessels, or the remnants of blood vessels, could provide a pathway for bacteria from the oral cavity. This might account for why some of these teeth develop periapical abscesses in spite of apparently having no pulp. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inferring chronological age from DNA methylation patterns of human teeth.

PubMed

Giuliani, Cristina; Cilli, Elisabetta; Bacalini, Maria Giulia; Pirazzini, Chiara; Sazzini, Marco; Gruppioni, Giorgio; Franceschi, Claudio; Garagnani, Paolo; Luiselli, Donata

2016-04-01

Current methods to determine chronological age from modern and ancient remains rely on both morphological and molecular approaches. However, low accuracy and the lack of standardized protocols make the development of alternative methods for the estimation of individual's age even more urgent for several research fields, such as biological anthropology, biodemography, forensics, evolutionary genetics, and ancient DNA studies. Therefore, the aim of this study is to identify genomic regions whose DNA methylation level correlates with age in modern teeth. We used MALDI-TOF mass spectrometry to analyze DNA methylation levels of specific CpGs located in the ELOVL2, FHL2, and PENK genes. We considered methylation data from cementum, dentin and pulp of 21 modern teeth (from 17 to 77 years old) to construct a mathematical model able to exploit DNA methylation values to predict age of the individuals. The median difference between the real age and that estimated using DNA methylation values is 1.20 years (SD = 1.9) if DNA is recovered from both cementum and pulp of the same modern teeth, 2.25 years (SD = 2.5) if DNA is recovered from dental pulp, 2.45 years (SD = 3.3) if DNA is extracted from cementum and 7.07 years (SD = 7.0) when DNA is recovered from dentin only. We propose for the first time the evaluation of DNA methylation at ELOVL2, FHL2, and PENK genes as a powerful tool to predict age in modern teeth for anthropological applications. Future studies are needed to apply this method also to historical and relatively ancient human teeth. © 2015 Wiley Periodicals, Inc.

Influence of Teaching Strategies and its Order of Exposure on Pre-Clinical Teeth Arrangement – A Pilot Study

PubMed Central

Mani, Uma Maheswari; Christian, Jayanth; Seenivasan, Madhan Kumar; Natarajan, Parthasarathy; Vaidhyanathan, Anand Kumar

2016-01-01

Introduction Teeth arrangement is a vital skill for the undergraduate dental student. The attainment of skills depends largely on the methodology of teaching. In a dental curriculum, the students are exposed to a wide variety of inputs and teaching methodologies from different sources. The educational unit in dental school must identify the sequence of teaching methods that enhance the learning and practising ability of students. Aim The aim of this study was to evaluate the effectiveness of three different teaching methodologies for teeth arrangement and compare the differences between the orders of exposure to each teaching methodology on the development of teeth arrangement skills. Materials and Methods The first year B.D.S students were study participants and were divided into three groups A, B, C. They were exposed to three teaching patterns namely live demonstration with video assisted teaching, group discussion with hand-outs and lectures with power point presentation. After each teaching methodology, their skill was assessed. The groups were exposed to three methodologies in different order for three arrangements. The scores obtained were analysed using Kruskal Wallis rank sum test and Dunn test for statistical significance. Results Significantly higher scores in the teeth arrangement procedure were obtained by the Group A students who were exposed initially to live demonstration with video-assisted teaching. Difference in the scores was noted among and within the groups. The difference between Group A and Group C was statistically significant after both first and third teeth arrangement (p=0.0031, p=0.0057). Conclusion The study suggests each pre-clinical practice should begin with a live demonstration to enhance immediate learning absorption followed by lectures with power point presentation and group discussion for retention of knowledge and memory retrieval. PMID:27891468

Influence of Teaching Strategies and its Order of Exposure on Pre-Clinical Teeth Arrangement - A Pilot Study.

PubMed

Jeyapalan, Karthigeyan; Mani, Uma Maheswari; Christian, Jayanth; Seenivasan, Madhan Kumar; Natarajan, Parthasarathy; Vaidhyanathan, Anand Kumar

2016-10-01

Teeth arrangement is a vital skill for the undergraduate dental student. The attainment of skills depends largely on the methodology of teaching. In a dental curriculum, the students are exposed to a wide variety of inputs and teaching methodologies from different sources. The educational unit in dental school must identify the sequence of teaching methods that enhance the learning and practising ability of students. The aim of this study was to evaluate the effectiveness of three different teaching methodologies for teeth arrangement and compare the differences between the orders of exposure to each teaching methodology on the development of teeth arrangement skills. The first year B.D.S students were study participants and were divided into three groups A, B, C. They were exposed to three teaching patterns namely live demonstration with video assisted teaching, group discussion with hand-outs and lectures with power point presentation. After each teaching methodology, their skill was assessed. The groups were exposed to three methodologies in different order for three arrangements. The scores obtained were analysed using Kruskal Wallis rank sum test and Dunn test for statistical significance. Significantly higher scores in the teeth arrangement procedure were obtained by the Group A students who were exposed initially to live demonstration with video-assisted teaching. Difference in the scores was noted among and within the groups. The difference between Group A and Group C was statistically significant after both first and third teeth arrangement (p=0.0031, p=0.0057). The study suggests each pre-clinical practice should begin with a live demonstration to enhance immediate learning absorption followed by lectures with power point presentation and group discussion for retention of knowledge and memory retrieval.

The radular apparatus of cephalopods

PubMed Central

Messenger, J. B.

1999-01-01

This paper describes the ontogeny, breakdown and absorption of the radular teeth of cephalopods and, for the first time, considers the function of the 'bolsters' or radular support muscles. The radular ribbon, which bears many regularly arranged transverse rows of teeth one behind the other, lies in a radular canal that emerges from the radular sac. Here the radular teeth are formed by a set of elongate cells with microvilli, the odontoblasts. These are organized into two layers, the outer producing the radular membrane and the bases of the teeth, the inner producing the cusps. The odontoblasts also secrete the hyaline shield and the teeth on the lateral buccal palps, when these are present. At the front end of the radular ribbon the teeth become worn in feeding and are replaced from behind by new ones formed continuously in the radular sac, so that the whole ribbon moves forward during ontogeny. Removal of the old teeth is achieved by cells in the radular organs; these cells, which are formed from modified odontoblasts ('odontoclasts'), dissolve the teeth and membranes and absorb them. There is a subradular organ in all cephalopods. In Octopus vulgaris, which bores into mollusc shells and crustacean carapaces, it is especially well-developed and there is also a supraradular organ. A characteristic feature of the cephalopod radular apparatus is the pair of large radular support muscles or 'bolsters'. Their function seems never to have been investigated, but experiments reported here show that when they elongate, the radular teeth become erect at the bending plane and splayed, presumably enhancing their ability to rake food particles into the pharynx. The bolsters of Octopus function as muscular hydrostats: because their volume is fixed, contraction of their powerful transverse muscles causes them to elongate. In decapods and in nautiloids each bolster contains a 'support rod' of semi-fluid material, as well as massive transverse musculature. This rod may elongate to erect the radular teeth. At the extreme front end of the bolsters in Octopus there are many nerve fibres that may constitute a receptor organ signalling the movements of the radula against hard material. Such nerves are absent from decapods and from octopods that do not bore holes. The buccal mass of Nautilus is massive, with heavily calcified tips to the beaks and a wide radular ribbon, with 13 rather than nine elements in each row. Nevertheless all the usual coleoid features are present in the radular apparatus and the teeth are formed and broken down in the same way. However, Nautilus has a unique structure, the radular appendage. This comprises a papillate mass extending over the palate in the mid-line and forming paired lateral masses that are in part secretory. The organ is attached to the front of the radula by muscles and connective tissue. Its function is unknown.

Taking Care of Your Teeth

MedlinePlus

... Educators Search English Español Taking Care of Your Teeth KidsHealth / For Kids / Taking Care of Your Teeth ... they help you look your best. Why Healthy Teeth Are Important How does taking care of your ...

Mouth and Teeth (For Parents)

MedlinePlus

... Videos for Educators Search English Español Mouth and Teeth KidsHealth / For Parents / Mouth and Teeth What's in ... daily lives. Basic Anatomy of the Mouth and Teeth The entrance to the digestive tract, the mouth ...

Take Care of Your Child's Teeth

MedlinePlus

... Topic En español Take Care of Your Child’s Teeth Browse Sections The Basics Overview Tooth Decay Take ... the toothpaste instead of swallowing it Make brushing teeth fun. Getting kids to brush their teeth can ...

Keeping Your Child's Teeth Healthy

MedlinePlus

... for Educators Search English Español Keeping Your Child's Teeth Healthy KidsHealth / For Parents / Keeping Your Child's Teeth ... and guidelines. When Should Kids Start Brushing Their Teeth? Good dental care begins before a baby's first ...

INVESTIGATING THE MANAGEMENT OF CARIOUS PRIMARY TEETH IN GENERAL DENTAL PRACTICE: AN OVERVIEW OF THE DEVELOPMENT AND CONDUCT OF THE FICTION TRIAL.

PubMed

Stewart, Matthew; Keightley, Alexander; Maguire, Anne; Chadwick, Barbara; Vale, Luke; Homer, Tara; Douglas, Gail; Deery, Chris; Marshman, Zoe; Ryan, Vicky; Innes, Nicola

2015-11-01

The management of carious primary teeth is a challenge for patients, parents and clinicians. Most evidence supporting different management strategies originates from a specialist setting and therefore its relevance to the primary care setting is questionable. The UK National Institute for Health Research (NIHR) Health Technology Assessment (HTA) has commissioned the FiCTION (Filling Children's Teeth: Indicated Or Not?) trial; a multi-centre primary dental care randomised controlled trial (RCT) to determine the most clinically and cost- effective approach to managing caries in the primary dentition in the UK. This large trial began in 2012, is due to be completed in late 2017 and involves 72 practices and 1,124 children initially aged three to seven years with dentine caries, following randomisation to one of three caries management strategies. Clinical, radiographic, quality of life, treatment acceptability and health economics data are collected during the three-year follow up period. This article provides an overview of the development and conduct of FiCTION and discusses some approaches adopted to manage challenges and achieve the patient recruitment target.

Molecular Genetics of Supernumerary Tooth Formation

PubMed Central

Wang, Xiu-Ping; Fan, Jiabing

2011-01-01

Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

Clinical performance of dental fiberscope image guided system for endodontic treatment.

PubMed

Yamazaki, Yasushi; Ogawa, Takumi; Shigeta, Yuko; Ikawa, Tomoko; Kasama, Shintaro; Hattori, Asaki; Suzuki, Naoki; Yamamoto, Takatsugu; Ozawa, Toshiko; Arai, Takashi

2011-01-01

We developed a dental fiberscope that can be navigated. As a result we are able to better grasp the device position relative to the teeth, aiming at the lesion more precisely. However, the device position and the precise target setting were difficult to consistently ascertain. The aim of this study is to navigate the position of tip of the dental fiberscope fiber in the root canal with our navigation system. A 3D tooth model was made from the raw dental CT data. In addition, the optical position of the measurement device, OPTOTRAK system was used for registration of the 3D model and actual teeth position and to chase the scope movement. We developed exclusive software to unify information. We were subsequently able to precisely indicate the relation of the position between the device and the teeth on the 3D model in the monitor. This allowed us to aim at the lesion more precisely, as the revised endoscopic image matched the 3D model. The application of this endoscopic navigation system could increase the success rate for root canal treatments with recalcitrant lesion.

Remineralization of primary tooth enamel from individuals with Down syndrome.

PubMed

Okamoto, Takuma; Shibata, Munenori; Tsuboi, Shinji; Nakagaki, Haruo; Fukuta, Osamu; Kusabe, Yoshitaka; Inukai, Junko

2011-01-01

The purpose of this study was to clarify the characteristics of primary tooth enamel of Down syndrome patients (DSPs). We examined 9 primary teeth of Down syndrome children and 11 primary teeth of normally developed children to investigate the remineralization processes of enamel by transverse microradiography and X ray micro analyzer (XMA). Mineral loss, lesion depth, maximum mineral value, minimum mineral value, depth of maximum mineral value, and depth of minimum mineral value were used to analyze transverse microradiography (TMR). In addition, we calculated the percentage of enamel remineralization. All the parameters in the 2 groups showed marked recovery. The results indicated that the Down syndrome group was significantly remineralized the same way as the control group. According to the comparison of mineral content distribution by XMA, the content distribution of magnesium was different between the 2 groups. While recovery through remineralization of primary teeth was similar between Down syndrome children and normally developed children, the mechanism of remineralization process may be different between the 2 groups; consequently, magnesium may be considered as one of the factors affecting recovery.

Nonsyndromic tooth agenesis patterns and associated developmental dental anomalies: a literature review with radiographic illustrations.

PubMed

Agarwal, P; Vinuth, D P; Dube, G; Dube, P

2013-01-01

Tooth agenesis is one of the most intriguing phenomena, because it is frequently associated with other oral anomalies, structural variations and malformations of other teeth, late eruption, transposition and crowding. The diagnosis can be quite challenging as radiographic examination is critical for the diagnosis but not always possible and the late developing teeth may be sometimes scored developmentally missing. Accurate diagnosis therefore requires radiographic, clinical, and dental cast examinations. It is an important clinical and public health problem. Patients with missing permanent teeth may suffer from a reduced chewing ability, inarticulate pronunciation, and an unfavorable aesthetic appearance. Clinically, early diagnosis of a dental anomaly can alert the clinician to the possible development of other associated dental anomalies in the same patient or family, and avoid the possible sequelae. Understanding of tooth agenesis patterns and their impact on diagnosis, prevention, and eventually therapeutics are becoming integral parts of comprehensive dental care. Dental examination with radiographic screening of hypodontia in early childhood should be emphasized as part of public oral health policy to allow early diagnosis and timely intervention.

Clinical Characteristics of Abutment Teeth with Gingival Discoloration.

PubMed

Ristic, Ljubisa; Dakovic, Dragana; Postic, Srdjan; Lazic, Zoran; Bacevic, Miljana; Vucevic, Dragana

2017-04-06

The grey-bluish discoloration of gingiva (known as "amalgam tattoo") does not appear only in the presence of amalgam restorations. It may also be seen in cases of teeth restored with cast dowels and porcelain-fused-to-metal (PFM) restorations. The aim of this article was to determine the clinical characteristics of abutment teeth with gingival discoloration. This research was conducted on 25 patients referred for cast dowel and PFM restorations. These restorations were manufactured from Ni-Cr alloys. Ninety days after cementing the fixed prosthodontic restorations, the abutment teeth (n = 61) were divided into a group with gingival discoloration (GD) (n = 25) and without gingival discoloration (NGD) (n = 36). The control group (CG) comprised the contralateral teeth (n = 61). Plaque index, gingival index, clinical attachment level, and probing depth were assessed before fabrication and also 90 days after cementation of the PFM restorations. The gingival index, clinical attachment level, and probing depths of the abutment teeth that had GD were statistically higher before restoration, in comparison with the abutment teeth in the NGD and control groups. Ninety days after cementation, the abutment teeth with GD had significantly lower gingival indexes and probing depths, compared to the abutment teeth in the NGD group. Both abutment teeth groups (GD and NGD) had significantly higher values of clinical attachment levels when compared to the control group. There were no statistically significant differences in plaque index values between the study groups. The results of this study indicated that impairment of periodontal status of abutment teeth seemed to be related to the presence of gingival discolorations. Therefore, fabrication of fixed prosthodontic restorations requires careful planning and abutment teeth preparation to minimize the occurrence of gingival discolorations. With careful preparation of abutment teeth for cast dowels and crown restorations it may be possible to decrease the frequency of gingival discolorations adjacent to abutment teeth. © 2017 by the American College of Prosthodontists.

Bioceramic/poly (glycolic)-poly (lactic acid) composite induces mineralized barrier after direct capping of rat tooth pulp tissue.

PubMed

Gala-Garcia, Alfonso; Teixeira, Karina Imaculada Rosa; Wykrota, Francisco Henrique Lana; Sinisterra, Rubén Dario; Cortés, Maria Esperanza

2010-01-01

The aim of this study was to observe the histopathological pulp response following direct pulp capping of mechanically exposed teeth in rats with a composite of beta-tricalcium phosphate-hydroxyapatite bioceramic (BC) and poly (glycolic)-poly (lactic acid) (PLGA) material or a calcium hydroxide [Ca(OH)2] material, compared to BC alone and a negative control of water. Pulp of the maxillary molars was exposed, followed by capping with the experimental material. The pulpal tissue response was assessed post-operatively at 1, 7, 14 and 30 d, followed by histological analysis. The Ca(OH)2 group exhibited severe acute inflammatory cell infiltration at day 14. However after 30 d, a new hard tissue with macro porous obliteration of the pulp chamber and a characteristic necrotic area had appeared. BC and Ca(OH)2 capping were associated with moderate inflammation and dentinal bridge similar. Meanwhile, in the BC/PLGA composite group, there was moderate inflammatory infiltrate and formation of a dense and complete dentinal bridge. In conclusion, the BC/PLGA composite material showed a large zone of tertiary dentin, and effectively reorganized the dentin-pulp complex.

Iron deposition in modern and archaeological teeth

NASA Astrophysics Data System (ADS)

Williams, A.-M. M.; Siegele, R.

2014-09-01

Iron surface concentrations and profile maps were measured on the enamel of archaeological and modern teeth to determine how iron is deposited in tooth enamel and if it was affected by the post-mortem environment. Teeth from Australian children who died in the second half of the 19th century were compared with contemporary teeth extracted for orthodontic purposes. Surface analysis of the teeth was performed using the 3 MV Van Der Graff Accelerator at The Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia. A small sample of teeth were then cut in the mid sagittal plane and analysed using ANSTO High Energy Heavy Ion Microprobe. Maps and linear profiles were produced showing the distribution of iron across the enamel. Results show that both the levels and distribution of iron in archaeological teeth is quite different to contemporary teeth, raising the suggestion that iron has been significantly altered by the post-mortem environment.

[Clinical application of IPS-empress 2 pressable all-ceramic crowns].

PubMed

Wang, Ai-jun; He, Xiao-ming; Liu, Li-xia; Zhang, Chao-biao; Zhang, Min; Shen, Bei-yong

2007-02-01

To evaluate the clinical prosthetic effect of IPS-Empress 2 pressahie ceramic crowns. 198 teeth of 70 patients were restored with IPS-Empress 2 pressahie ceramic crowns. The patients were asked to return in one week and every half year. The clinical prosthetic effect was evaluated. Through follow-up of 3-38 months, the veneer porcelain crowns of 3 teeth were broken. 2 crowns fall off due to teeth fracture, gingivitis occurred in 2 teeth, pulpitis or periapical periodontitis occurred in 3 teeth. The shades of 3 crowns were darkening. The prosthetic effect of 185 teeth was satisfied. The rate of satisfaction was 93.4%. IPS-Empress 2 pressable all-ceramic crown has the advantages of aesthetic effect, good hiocompatihility and simple fabrication. But its strength is not enough for posterior teeth and it can not cover the deep color of non-vital teeth and metal materials.

The epidemiology of supernumerary teeth and the associated molecular mechanism

PubMed Central

Lu, Xi; Yu, Fang; Liu, Junjun; Cai, Wenping; Zhao, Yumei; Zhao, Shouliang; Liu, Shangfeng

2017-01-01

ABSTRACT Supernumerary teeth are common clinical dental anomalies. Although various studies have provided abundant information regarding genes and signaling pathways involved in tooth morphogenesis, which include Wnt, FGF, BMP, and Shh, the molecular mechanism of tooth formation, especially for supernumerary teeth, is still unclear. In the population, some cases of supernumerary teeth are sporadic, while others are syndrome-related with familial hereditary. The prompt and accurate diagnosis of syndrome related supernumerary teeth is quite important for some distinctive disorders. Mice are the most commonly used model system for investigating supernumerary teeth. The upregulation of Wnt and Shh signaling in the dental epithelium results in the formation of multiple supernumerary teeth in mice. Understanding the molecular mechanism of supernumerary teeth is also a component of understanding tooth formation in general and provides clinical guidance for early diagnosis and treatment in the future. PMID:28598258

An overlay partial denture to restore worn mandibular anterior teeth.

PubMed

Samant, Asha; DeSciscio, Peter

2014-01-01

Restoring worn anterior mandibular teeth is a challenge, especially when teeth are small, esthetics are a concern, the long-term prognosis is questionable, and/or patient finances are an issue. This article describes an alternate treatment for a patient with a collapsed bite, missing posterior mandibular teeth, an ill-fitting complete maxillary denture with poor esthetics, and irregular, worn mandibular anterior teeth.

Comparison of the microhardness of primary and permanent teeth after immersion in two types of carbonated beverages

PubMed Central

Haghgou, Hamid R.; Haghgoo, Roza; Asdollah, Fatemah Molla

2016-01-01

Objectives: The consumption of carbonated beverages is one of the etiological factors that cause dental erosion. The purpose of this research was to compare changes in the microhardness of permanent and primary teeth after immersion in two types of carbonated beverages. Materials and Methods: This investigation was done on 30 healthy permanent molars and 30 healthy primary canines. Each group of primary and permanent teeth was subdivided into three groups of 10 teeth. The teeth was immersed in 40 ml of each of the three beverages for 5 min. One subgroup was immersed in water (as a control). The next was immersed in Lemon Delster and the last subgroup was immersed in Coca-Cola. The microhardness of enamel was measured using the Vickers method before and after immersion. Finally, the data was analyzed by paired t-test, one-way analysis of variance, and t-test. Results: Microhardness reduction in the primary teeth was significant in both the Lemon Delster and Coca-Cola groups (P < 0.05). This reduction was also statistically significant in the permanent teeth (P < 0.05). A comparison of the enamel changes in the primary teeth with permanent teeth after immersion in both beverages showed a greater microhardness reduction in the primary teeth in both the experimental groups. Conclusions: Coca-Cola and Lemon Delster caused a significant reduction of microhardness in tooth enamel. This reduction was greater in primary teeth than in permanent teeth, and was also greater after immersion in Coca-Cola than after immersion in Lemon Delster. PMID:27583223

In vitro study of heat production during power reduction of equine mandibular teeth.

PubMed

Allen, Martin L; Baker, Gordon J; Freeman, David E; Holmes, Kenneth R; Marretta, Sandra Manfra; Scoggins, R Dean; Constable, Peter

2004-04-01

To measure the amount of heat generated during 3 methods of equine dental reduction with power instruments. In vitro study. 30 premolar and molar teeth removed from mandibles of 8 equine heads collected at an abbatoir. 38-gauge copper-constantan thermocouples were inserted into the lingual side of each tooth 15 mm (proximal) and 25 mm (distal) from the occlusal surface, at a depth of 5 mm, which placed the tip close to the pulp chamber. Group-NC1 (n = 10) teeth were ground for 1 minute without coolant, group-NC2 (10) teeth were ground for 2 minutes without coolant, and group-C2 (10) teeth were ground for 2 minutes with water for coolant. Mean temperature increase was 1.2 degrees C at the distal thermocouple and 6.6 degrees C at the proximal thermocouple for group-NC1 teeth, 4.1 degrees C at the distal thermocouple and 24.3 degrees C at the proximal thermocouple for group-NC2 teeth, and 0.8 degrees C at the distal thermocouple and -0.1 degrees C at the proximal thermocouple for group-C2 teeth. In general, an increase of 5 degrees C in human teeth is considered the maximum increase before there is permanent damage to tooth pulp. In group-NC2 teeth, temperature increased above this limit by several degrees, whereas in group-C2 teeth, there was little or no temperature increase. Our results suggest that major reduction of equine teeth by use of power instruments causes thermal changes that may cause irreversible pulp damage unless water cooling is used.

Non-masticatory uses of anterior teeth of Sima de los Huesos individuals (Sierra de Atapuerca, Spain).

PubMed

Lozano, Marina; Bermúdez de Castro, José M; Carbonell, Eudald; Arsuaga, Juan Luis

2008-10-01

In this study we examine the labial and occlusal surfaces of incisors and canines of hominins recovered from the Sima de los Huesos (SH), middle Pleistocene site, in order to establish the possible extra-masticatory use of anterior teeth. We have compared the microwear of these fossils with microwear from the anterior teeth of Australian Aborigines, a population characterized by ethnographic evidence of the use of their teeth as a third hand. These two samples of teeth were microscopically analyzed using Scanning Electron Microscopy (SEM). Our results support the "cultural" origin of microwear observed on fossil teeth: we conclude that the SH hominins used their anterior teeth as a "third hand" for para- or extra-masticatory activities.

Tissue reaction to a triantibiotic paste used for endodontic tissue self-regeneration of nonvital immature permanent teeth.

PubMed

Gomes-Filho, João Eduardo; Duarte, Paulo Carvalho Tobias; de Oliveira, Claudiel Batista; Watanabe, Simone; Lodi, Carolina Simonetti; Cintra, Luciano Tavares Ângelo; Bernabé, Pedro Felício Estrada

2012-01-01

The endodontic regenerative procedure (ERP), which is an alternative to calcium hydroxide-induced apexification, involves the use of a triple antibiotic paste (TAP) as a dressing material. The aim of this study was to evaluate the response of rat subcutaneous tissue to implanted polyethylene tubes that were filled with TAP or calcium hydroxide. Thirty rats received 2 individual implants of polyethylene tubes filled with TAP or calcium hydroxide paste (CHP) and another empty tube as a control. Thirty additional rats received 2 individual implants consisting of polyethylene tubes filled with dressing material carriers (macrogol and propylene glycol) and a sham procedure. After 7, 15, 30, 60, and 90 days, 12 animals were euthanized, and the tubes and surrounding tissue were removed and processed for histology by using glycol methacrylate and stained with hematoxylin and eosin. The histological score ranged from 0 to 3 depending on the content of inflammatory cells; the fibrous capsule was considered thin or thick, and necrosis and calcification were recorded as present or absent. The results were analyzed using the Kruskal-Wallis test. Both dressing materials induced moderate reactions at 7 and 15 days. These reactions were similar to the control (P > .05) and reduced in intensity (to mild) from day 30 onward (P > .05). The carriers did not interfere with the reaction of the dressing materials. TAP and CHP were biocompatible over the different experimental periods examined. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Single-visit endodontic treatment of mature teeth with chronic apical abscesses using mineral trioxide aggregate cement: a randomized clinical trial.

PubMed

Alsulaimani, Reem Siraj

2016-08-23

Mature teeth with chronic apical abscesses characterized by intermittent discharge of pus through an associated sinus tract. This communication between oral mucosa and periapical inflammation is challenging for the sealing ability of root canal obturation material. Therefore, the study aim was to compare the outcomes of endodontic treatment using mineral trioxide aggregate (MTA) cement to the conventional gutta-percha cone and root canal sealer as an obturation material in mature teeth with chronic apical abscesses. Mature teeth with chronic apical abscesses referred to our clinic for root canal treatment between 2010 and 2012 were treated in a single visit and distributed among treatment (T) and control (C) groups using a predetermined randomization block (TCTC). After chemo-mechanical preparation, teeth in group T received MTA cement mixed in a 0.26 water to powder ratio, and teeth group C received gutta-percha and root canal sealer using the warm vertical technique. The treatment outcomes were defined as obturation length, periapical healing, resorption of extruded material, and survival rate at least 2.5 years after treatment. Three endodontists blinded to the type of obturation material documented treatment outcomes. Statistical analysis at P < 0.05 was conducted to measure difference between the groups. Thirty-six teeth were treated between 2010 and 2012, and 32 teeth were evaluated in 2015. Complete periapical healing was observed in 87.5 % of MTA-treated teeth and 75.0 % of gutta-percha-treated teeth. Adequate obturation length was reported in 50.0 % of MTA-treated and 37.5 % of gutta-percha-treated teeth. Complete resorption of extruded material was evident in 83.3 % MTA-treated teeth and 100.0 % gutta-percha-treated teeth. The survival rate of MTA-treated teeth was 100 % at 3, and 5 years, while the survival rate of gutta-percha-treated teeth was 83.3 % at 3, and 5 years. There was no significant difference between the groups in term of periapical healing, survival rate, obturation length, or resorption of extruded material. The outcomes of single-visit endodontic treatment of mature teeth with chronic apical abscesses using MTA cement were better, but not statistically significant, compared to conventional treatment. ISRCTN15285974 . Registered retrospectively 23 June 2015.

[Effect of revascularization treatment of immature permanent teeth with endodontic infection].

PubMed

Huang, Yibin; Chen, Ke; Zhang, Ying; Xiong, Huacui; Liu, Caiqi

2013-05-01

To observe the effect of revascularization for treatment of immature teeth with endodontic infection mediated by calcium hydroxide. Seventeen pediatric patients with endodontic infections of the permanent teeth were treated with routine root canal and pulp cavity irrigation and disinfection followed by application of calcium hydroxide paste to the root canal orifice to induce revascularization. Another 17 patients received conventional apexification procedures to serve as the control group. The patients were followed up to observe the therapeutic effect of the treatments. In the revascularization treatment group, 4 cases showed healed periapical lesions 6 to 18 months after the surgery with thickened root canal walls and closure of the apical foramen; in 10 cases, the periapical lesions healed 12 to 18 months postoperatively with lengthened root, thickened root canal wall, and narrowed apical foramen. One patient reported pain and swelling at 2 months, and 2 patients showed the formation of gum fistula and ceased development of the roots at 7 and 8 months. In the control group, the periapical lesions healed in 1 cases at 12 months postoperatively with apical foramen closure; in 11 cases, hard tissues formed in the root apex without obviously lengthened roots 6 to 8 months after the surgery; in 5 cases, no apical barrier formed even 12 to 18 months after the surgery. The overall effective rates were similar between the two groups (P>0.05). Revascularization by calcium hydroxide sealing can promote root development of immature permanent teeth with pulpitis or periradicular periodontitis.

Role of basic biological sciences in clinical orthodontics: a case series.

PubMed

Davidovitch, Ze'ev; Krishnan, Vinod

2009-02-01

Orthodontic therapy is based on interaction between mechanics and biology. Basic biologic research aims at developing a better understanding of the mechanism of transformation of mechanical energy into biologic reactions, and exposing the reasons for iatrogenic tissue damage in orthodontics. Previous research has shown that inflammation is a major part of the biologic response to orthodontic forces. In inflammation, signal molecules that originate in remote diseased organs can reach strained paradental tissues and exacerbate the inflammatory process, leading to tissue damage. Our case series includes 3 patients, each having had systemic diseases and malocclusion. One had diabetes mellitus, Hashimoto's thyroiditis, and depression. Concern about the possible effect of these conditions on the well-being of the teeth and their surrounding tissues compelled the orthodontist to choose not to treat this patient. The other 2 patients had allergies, and 1 also had bronchial asthma and bruises. Although these conditions are thought to be risk factors for root resorption, these patients received orthodontic treatment for 2 and 3.5 years, respectively. At the end of treatment, both had excessive root resorption of many teeth. In 1 patient, this damage led to the loss of most maxillary teeth. Basic research should continue to address questions related to the biologic mechanisms of tooth movement on tissue, cellular, and molecular levels. Moreover, this research should continue to identify risk factors that might jeopardize the longevity of treated teeth. Such basic research should promote the development of new tissue-friendly and patient-friendly therapeutic methods.

Histobacteriologic Conditions of the Apical Root Canal System and Periapical Tissues in Teeth Associated with Sinus Tracts.

PubMed

Ricucci, Domenico; Loghin, Simona; Gonçalves, Lucio S; Rôças, Isabela N; Siqueira, José F

2018-03-01

This histobacteriologic study described the pattern of intraradicular and extraradicular infections in teeth with sinus tracts and chronic apical abscesses. The material comprised biopsy specimens from 24 (8 untreated and 16 treated) roots of teeth associated with apical periodontitis and a sinus tract. Specimens were obtained by periradicular surgery or extraction and were processed for histobacteriologic and histopathologic methods. Bacteria were found in the apical root canal system of all specimens, in the main root canal (22 teeth) and within ramifications (17 teeth). Four cases showed no extraradicular infection. Extraradicular bacteria occurred as a biofilm attached to the outer root surface in 17 teeth (5 untreated and 12 treated teeth), as actinomycotic colonies in 2 lesions, and as planktonic cells in 2 lesions. Extraradicular calculus formation (mineralized biofilm) was evident in 10 teeth. Teeth with chronic apical abscesses and sinus tracts showed a very complex infectious pattern in the apical root canal system and periapical lesion, with a predominance of biofilms. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Gear Crack Propagation Path Studies-- Guidelines Developed for Ultrasafe Design

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2002-01-01

Effective gear designs balance strength, durability, reliability, size, weight, and cost. However, unexpected gear failures may occur even with adequate gear tooth design. To design an extremely safe system, the designer must ask and address the question "What happens when a failure occurs?" With regard to gear-tooth bending fatigue, tooth or rim fractures may occur. For aircraft, a crack that propagated through a rim would be catastrophic, leading to the disengagement of a rotor or propeller, the loss of an aircraft, and possible fatalities. This failure mode should be avoided. However, a crack that propagated through a tooth might or might not be catastrophic, depending on the design and operating conditions. Also, early warning of this failure mode might be possible because of advances in modern diagnostic systems. An analysis was performed at the NASA Glenn Research Center to develop design guidelines to prevent catastrophic rim fracture failure modes in the event of gear-tooth bending fatigue. The finite element method was used with principles of linear elastic fracture mechanics. Crack propagation paths were predicted for a variety of gear tooth and rim configurations. The effects of rim and web thicknesses, initial crack locations, and gear-tooth geometry factors such as diametral pitch, number of teeth, pitch radius, and tooth pressure angle were considered. Design maps of tooth and rim fracture modes, including the effects of gear geometry, applied load, crack size, and material properties were developed. The occurrence of rim fractures significantly increased as the backup ratio (rim thickness divided by tooth height) decreased. The occurrence of rim fractures also increased as the initial crack location was moved down the root of the tooth. Increased rim and web compliance increased the occurrence of rim fractures. For gears with constant-pitch radii, coarser-pitch teeth increased the occurrence of tooth fractures over rim fractures. Also, 25 degree pressure angle teeth increased the occurrence of tooth fractures over rim fractures in comparison to 20 pressure angle teeth. For gears with a constant number of teeth or for gears with constant diametral pitch, varying size had little or no effect on crack propagation paths.

Implant site development by orthodontic forced extraction: a preliminary study.

PubMed

Amato, Francesco; Mirabella, A Davide; Macca, Ugo; Tarnow, Dennis P

2012-01-01

To evaluate the soft and hard tissue response to orthodontic implant site development (OISD) (ie, forced extraction), to measure the amount of tissue that was regenerated and its relationship to the amount of orthodontic vertical tooth movement, to evaluate the tissue response in teeth with different degrees of periodontal attachment loss, to understand the limits of OISD, and to evaluate the implant survival rate. A total of 32 hopeless teeth were treated with OISD, and 27 implants were placed in 13 patients consecutively. The level of periodontal attachment on the teeth to be extracted, amount of augmented alveolar bone, changes in soft tissue volume, and the rate of orthodontic tooth movement were recorded. Mean values after OISD were as follows: orthodontic extrusive movement, 6.2 ± 1.4 mm; bone augmentation, 4 ± 1.4 mm; coronal movement of the gingival margin, 3.9 ± 1.5 mm; coronal movement of the mucogingival junction, 2.1 ± 1.3 mm; keratinized gingival augmentation, 1.8 ± 1.1 mm; gingival thickness (buccolingual dimension) augmentation, 0.7 ± 0.4 mm; recession, 1.8 ± 1.2 mm; bone augmentation/orthodontic movement ratio (efficacy), 68.9% ± 17.3%; gingival augmentation/orthodontic movement ratio (efficacy), 65.2% ± 19.9%; and pocket depth reduction, 1.8 ± 0.9 mm. The implant survival rate was 96.3%. OISD was a viable treatment for these hopeless teeth to regenerate hard and soft tissues. Its efficacy was about 70% for bone regeneration and 60% for gingival augmentation. The residual attachment level on the tooth was not a limitation. OISD might be a valuable treatment option to regenerate tissues for implant site development in patients in need of conventional orthodontic therapy.

Tissue Engineering Considerations in Dental Pulp Regeneration

PubMed Central

Nosrat, Ali; Kim, Jong Ryul; Verma, Prashant; S. Chand, Priya

2014-01-01

Regenerative endodontic procedure is introduced as a biologically based treatment for immature teeth with pulp necrosis. Successful clinical and radiographic outcomes following regenerative procedures have been reported in landmark case reports. Retrospective studies have shown that this conservative treatment allows for continued root development and increases success and survival rate of the treated teeth compared to other treatment options. Although the goal of treatment is regeneration of a functional pulp tissue, histological analyses show a different outcome. Developing predictable protocols would require the use of key elements for tissue engineering: stem cells, bioactive scaffolds, and growth factors. In this study we will review the evidence based steps and outcomes of regenerative endodontics. PMID:24396373

Mouth and Teeth: How To Keep Them Healthy

MedlinePlus

... and Wellness Staying Healthy Healthy Living Mouth and Teeth: How to Keep Them Healthy Mouth and Teeth: How to Keep Them Healthy Share Print Taking good care of your mouth and teeth throughout your whole life can help prevent problems ...

[Research on the designing method of a special shade guide for tooth whitening].

PubMed

Xu, Yingxin

2015-10-01

To investigate a method of designing an accurate and scientific shade guide, especially used for judging the effect of tooth whitening, by analyzing the colorimetric values of discolored teeth statistically. One hundred thirty-six pictures of patients who had been receiving the Beyond cold light whitening treatment from February 2009 to July 2014 were analyzed, including 25 tetracycline teeth, 61 mottled-enamel teeth, and 50 yellow teeth. The colorimetric values of discolored teeth were measured. The L* values of shade tabs were calculated by hierarchical clustering of those of discolored teeth. The a* and b* values of shade tabs were the mean of those observed for discolored teeth. Accordingly, different shade guides were designed for each type of discolored teeth, and the effects were evaluated. A statistically significant difference in colorimetric values was found among the three types of discolored teeth. Compared with the Vitapan Classical shade guide, the shade guides designed through the present method were more scientific and accurate in judging the effect of tooth whitening. Moreover, the arrangement of shade tabs was more logical, and the color difference between shade tabs and discolored teeth was smaller. The proposed designing method is theoretically feasible, although its clinical effect has yet to be proven.

Influence of growth hormone therapy on selected dental and skeletal system parameters.

PubMed

Partyka, Małgorzata; Chałas, Renata; Dunin-Wilczyńska, Izabella; Drohomyretska, Myroslava; Klatka, Maria

2018-03-14

Growth hormone deficiency (GHD) is one of the main indications for growth hormone therapy. One characteristic of this disease is bone age delay in relation to the chronological age. Pituitary dysfunction negatively affects the growth and development of the jaws and teeth of the child. The secretion of endocrine glands regulates growth, development, and gender differentiation. It also controls the growth of bones and teeth, regulates metabolism of calcium and phosphate, proteins, lipids and carbohydrates. The primary role in the endocrine system is played by the pituitary gland which is responsible for the production of somatotropin [1]. Dysfunction of the pituitary gland has a negative effect on the growth and development of long bones in the body, and may have an adverse effect on the development of maxilla, mandible and dentition of a child. There is some information in the literature that dental age is delayed in short stature children; the replacement of deciduous teeth by permanent teeth is also delayed, and newly erupted permanent teeth often require orthodontic treatment. Applying hormonal therapy positively affects the process of replacement of dentition [2, 3, 4, 5, 6]. The aim of the study was to assess bone and dental age, as well as analyze the state of dentition in children diagnosed with GH deficiency treated with growth hormone, depending on the duration of treatment. The study material consisted of 110 children (27 males, 83 females), hospitalized for somatotropin hypopituitarism in the Department of Paediatric Endocrinology and Diabetology at the Medical University of Lublin, Poland. The mean birth age was 13 years (156 months) with a standard deviation of 2 years and 6 months (30 months). 47 children (43%) started treatment with the growth hormone (group starting treatment) and 63 children (57%) whose treatment was started 2-3 years previously (group in the course of treatment). The control group consisted of 41 generally healthy children (15males, 25 females) with ENT problems, such as hypoacusis and a condition after nasal injury, hospitalized in the Department of Paediatric Otolaryngology at the Medical University of Lublin, Poland. The mean age was 11 years and 5 months (137 months) with standard deviation of 2 years and 5 months (29 months). Informed consent was obtained from the parents. The study was approved by the Bioethical Committee at the Medical University of Lublin (Resolution No. KE-0254 /216 /2012).

A 12-Year Retrospective Study of Avulsion Cases in a Public Brazilian Dental Trauma Service.

PubMed

Mesquita, Gabriela Campos; Soares, Priscilla Barbosa Ferreira; Moura, Camilla Christian Gomes; Roscoe, Marina Guimarães; Paiva, Saul Martins; Soares, Carlos José

2017-01-01

This study assessed the epidemiological characteristics and management of the permanent teeth avulsion cases attended in a Brazilian dental trauma service from December 2005 to August 2016. A retrospective study was conducted of case records of 93 patients involving 139 avulsed teeth. Data included sex, age, trauma etiology, location of the accident, number and position of avulsed teeth, and presence and type of associated traumatic lesions. Management of the avulsed teeth was addressed as: time elapsed until teeth were retrieved from the accident's location; teeth's cleaning method and storage media; time elapsed until seeking treatment and replantation. The majority of the patients were children from 6-10 (31.2%) and 11-15 years old (26.9%). Male patients were more affected than female. Bicycle accident was the main etiological factor (31.2%). In 56 (60.2%) cases, traumatic lesions to neighboring teeth were present. In 55 (59.1%) cases, lesions to adjacent soft tissues were reported. In 82 (88.2%) cases, patients requested treatment at the same day of the accident. Sixty-four teeth (46.0%) were immediately retrieved and 28 (20.1%) were not found. Forty-two teeth (30.2%) were kept dry. Only one tooth (0.7%) was immediately replanted at the accident's site, while 51 teeth (36.7%) were not replanted. Numerous avulsed teeth were inappropriately managed and immediate replantation was not frequent. Public policies must be created to raise awareness towards the particularities of avulsion cases.

Characteristics of dental pulp in human upper first premolar teeth based on immunohistochemical and morphometric examinations.

PubMed

Tomaszewska, Joanna Maria; Miskowiak, Bogdan; Matthews-Brzozowska, Teresa; Wierzbicki, Piotr

2013-01-01

Teeth extracted for orthodontic reasons are commonly considered as healthy. Therefore, it is possible to examine structure of the dental pulp can be fully recognized and how it is affected by malocclusion. The aim of the study was to evaluate by immunohistochemistry (IHC) and morphometry dental pulp in human upper first premolar teeth extracted for orthodontic reasons. The material comprised 36 teeth of 20 patients in the age range 16-26 years. By the use of IHC markers the presence of immunocompetent cells (CD20, CD45RO, and CD68), blood vessels (CD31) and nerves (PGP9.5) were examined in the pulp. Inflammatory infiltrates and tissue atrophy were observed in 24 and 10 teeth, respectively. Strong positive correlation between the width of the odontoblastic layer, the number of rows of odontoblast nuclei and the increase of MVA (microvessel area) in the pulp of atrophic teeth was found. The cellular infiltrations found in H&E-stained sections were identified by IHC as memory T cells (CD45RO+) and B lymphocytes (CD20+) with macrophages (CD68+) present at the periphery. The CD20 antigen was intensively expressed in 13 teeth, CD45RO in 33 teeth, and CD68 in 20 teeth. Thus, despite the lack of any clinical signs of pulp disease many teeth extracted for orthodontic reasons show focal pulp inflammation and atrophy which probably results from the malocclusion stress accompanying teeth crowding.

Assessing the association of taurodontism with numeric dentition anomalies in an adult central Indian population.

PubMed

Puttalingaiah, Vinuth Dundanahalli; Agarwal, Poonam; Miglani, Rohit; Gupta, Puneet; Sankaran, Abilash; Dube, Gunjan

2014-07-01

To study the association between taurodontism and numeric anomalies in adult population. Out of 1,012; 946 panoramic radiographs and dental records were retrospectively assessed to determine the presence of dental agenesis and supernumerary and taurodont teeth. Taurodontism of one or more teeth was observed in 164 cases (97 females and 67 males). Hypodontia was observed in 148 patients (84 females and 64 males) with 62 patients having associated taurodontism (38 females, 24 males), oligodontia in 12 patients (five females and seven males) of whom nine patients also had taurodontism of one or more teeth (five females and four males). Forty-five patients (32 females and 13 males) presented with 57 supernumerary teeth (ST) with 12 patients having simultaneous presence of taurodontic tooth (seven females and five males). Our study suggests a preferential association between tooth agenesis and taurodontism; however, such association was not observed in individuals with hyperdontia. Understanding the nature of this preferential association may be of importance in determining the etiology of both conditions. This association may also define a subphenotype for future genetic studies on dental development. Further molecular studies are necessary to verify the etiology and mechanism of taurodontism associated with tooth agenesis.

Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects.

PubMed

Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

2013-07-01

This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simplified, probing pocket depth, clinical attachment level and number of teeth present, teeth with active carious lesions were recorded. Salivary flow rate and pH was recorded and subjected to biochemical investigation. Estimation of inorganic calcium and phosphate was performed by colorimetric method. Results showed statistically significant increase in salivary inorganic calcium and phosphate levels, poor oral hygiene status, pH and salivary flow rate in patients with periodontitis when compared with dental caries group and controls. Individuals who have increased salivary inorganic calcium, phosphate, pH, flow rate and maintain poor oral hygiene could be at a higher risk for developing periodontitis and may have less dental caries and more number of intact teeth.

Emergency Dose Estimation Using Optically Stimulated Luminescence from Human Tooth Enamel.

PubMed

Sholom, S; Dewitt, R; Simon, S L; Bouville, A; McKeever, S W S

2011-09-01

Human teeth were studied for potential use as emergency Optically Stimulated Luminescence (OSL) dosimeters. By using multiple-teeth samples in combination with a custom-built sensitive OSL reader, (60)Co-equivalent doses below 0.64 Gy were measured immediately after exposure with the lowest value being 27 mGy for the most sensitive sample. The variability of OSL sensitivity, from individual to individual using multiple-teeth samples, was determined to be 53%. X-ray and beta exposure were found to produce OSL curves with the same shape that differed from those due to ultraviolet (UV) exposure; as a result, correlation was observed between OSL signals after X-ray and beta exposure and was absent if compared to OSL signals after UV exposure. Fading of the OSL signal was "typical" for most teeth with just a few of incisors showing atypical behavior. Typical fading dependences were described by a bi-exponential decay function with "fast" (decay time around of 12 min) and "slow" (decay time about 14 h) components. OSL detection limits, based on the techniques developed to-date, were found to be satisfactory from the point-of-view of medical triage requirements if conducted within 24 hours of the exposure.

Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects

PubMed Central

Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

2013-01-01

Background and Objectives: This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. Materials and Methods: The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simplified, probing pocket depth, clinical attachment level and number of teeth present, teeth with active carious lesions were recorded. Salivary flow rate and pH was recorded and subjected to biochemical investigation. Estimation of inorganic calcium and phosphate was performed by colorimetric method. Results: Results showed statistically significant increase in salivary inorganic calcium and phosphate levels, poor oral hygiene status, pH and salivary flow rate in patients with periodontitis when compared with dental caries group and controls. Interpretation and Conclusion: Individuals who have increased salivary inorganic calcium, phosphate, pH, flow rate and maintain poor oral hygiene could be at a higher risk for developing periodontitis and may have less dental caries and more number of intact teeth. PMID:24174724

Pulp revascularization of immature permanent teeth: a review of the literature and a proposal of a new clinical protocol.

PubMed

Namour, Mélanie; Theys, Stephanie

2014-01-01

Tissue engineering is a growing field. In the near future, it will probably be possible to generate a complete vital tooth from a single stem cell. Pulp revascularization is dependent on the ability of residual pulp and apical and periodontal stem cells to differentiate. These cells have the ability to generate a highly vascularized and a conjunctive rich living tissue. This one is able to colonize the available pulp space. Revascularization is a new treatment method for immature necrotic permanent teeth. Up to now, apexification procedures were applied for these teeth, using calcium dihydroxide or MTA to produce an artificial apical barrier. However, the pulp revascularization allows the stimulation of the apical development and the root maturation of immature teeth. Two pulp revascularization techniques are used in the literature, one using calcium dihydroxide and the second using a triple antibiotic paste. Based on these two different pulp revascularization protocols, which obtain the desired therapeutic success, the literature will be reviewed and analyzed according to the relevance of their choice of materials. Based on the literature, we propose a new relevant protocol and a new mixture of antibiotics.

Prevalence of crown trauma in free-ranging maned wolves (Chrysocyon brachyurus) in central Brazil.

PubMed

Furtado, Mariana Malzoni; Kashivakura, Cyntia Kayo; Ferro, Claudia; Jácomo, Anah Tereza de Almeida; Silveira, Leandro; Astete, Samuel; Lopes, Fernanda Maria

2007-12-01

Nineteen free-ranging maned wolves (Chrysocyon brachyurus) were captured in central Brazil from April through November 2003. Oral cavity examination revealed 34 teeth with crown trauma in twelve animals. Canine teeth were most commonly affected (44.2%), followed by premolar (29.4%) and incisor teeth (26.5%). Trauma to maxillary teeth (67.7%) was more frequent compared with mandibular teeth (32.3 %). The majority of dental fractures were located at the cuspid portion of the crown (56.0%). Slab fractures were the most frequent type (37.0%), followed by horizontal (24.0%), oblique (24.0%) and longitudinal fractures (15.0%). Complicated crown fracture (pulp exposure) was diagnosed in 13 (38.2%) of these teeth while pulpitis noted by tooth discoloration was diagnosed in 8 (23.5%) teeth.

Biomechanical evaluation of the natural abutment teeth in combined tooth-implant-supported telescopic prostheses: a three-dimensional finite element analysis.

PubMed

Chen, Yu; Wang, Chao; Huang, Yuanding; Feng, Tianming; Zou, Huawei; Fan, Yubo

2017-07-01

Telescopic overdentures supported by the combination of natural teeth and implants have been thought a valuable treatment for the severely compromised partially edentulous patients. But the combination of teeth and implants involves highly complex biomechanical problems. This study is to evaluate biomechanical behaviors of the natural abutment teeth with the treatment of combined tooth-implant supported telescopic crown prostheses in mandible through 3D FEA. According to this study, the prosthetic option supported by a combination of teeth and implants and retained by double crowns could protect teeth and their periodontal support tissues acting as a rigid splint, and may be a valuable treatment option for partially edentulous patients with severely reduced remaining teeth in mandible.

Association Between Missing Posterior Teeth and Occurrence of Temporomandibular Joint Condylar Erosion: A Cone Beam Computed Tomography Study.

PubMed

Bertram, Felix; Hupp, Linus; Schnabl, Dagmar; Rudisch, Ansgar; Emshoff, Rüdiger

To determine a possible association between asymptomatic temporomandibular joint (TMJ) condylar erosion and the number of missing posterior teeth and their location, as well as the number of dental quadrants with missing posterior teeth. This case-control study involved 210 patients (male to female ratio = 98:112) aged 16-74 years, with 105 asymptomatic patients with TMJ condylar erosion and a control group of 105 patients without TMJ condylar erosion. Cone beam computed tomography images were evaluated to classify the severity of TMJ condylar erosion as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion). The number of missing posterior teeth (mean ± standard deviation [SD]; 2.7 ± 2.4 vs 0.7 ± 1.2) (P < .001), number of dental quadrants with missing posterior teeth (1.5 ± 1.3 vs 0.6 ± 0.9) (P < .001), and bilateral location of missing posterior teeth (41 ± 39.0 vs 10 ± 9.5) (P < .001) were all significantly higher in patients with erosion than in those without erosion. The condylar erosion grade was significantly associated with the number of missing posterior teeth (odds ratio [OR] = 1.24; P = .006), the number of dental quadrants with missing posterior teeth (OR = 1.36; P = .006), and the bilateral occurrence of missing posterior teeth (OR = 3.03; P = .002). The findings from this study suggest a possible association between TMJ condylar erosion grades and the number of missing posterior teeth, the number of quadrants with missing posterior teeth, and the bilateral occurrence of missing posterior teeth.

External root resorption during orthodontic treatment in root-filled teeth and contralateral teeth with vital pulp: A clinical study of contributing factors.

PubMed

Lee, Yun Ju; Lee, Tae Yeon

2016-01-01

There is a lack of research to support the belief that root canal treatment can be considered for stopping or decreasing external apical root resorption (EARR). There is conflicting evidence as to whether root-filled teeth are more or less likely to experience EARR after orthodontic treatment. The purpose of this study was to compare the degree of EARR of root-filled teeth with that of contralateral teeth with vital pulp after fixed orthodontic treatment. The study sample consisted of 35 patients aged 25.23 ± 4.92 years who had at least 1 root-filled tooth before orthodontic treatment. Digital panoramic radiographs of each patient taken before and after orthodontic treatment were used to measure the EARR. The Student t test for matched pairs and the Pearson correlation analysis were applied. The mean EARR values were 0.22 (0.14, 0.35) for root-filled teeth and 0.87 (0.59, 1.31) for contralateral teeth with vital pulp, indicating significantly less EARR for root-filled teeth compared with the contralateral teeth with vital pulp after orthodontic treatment. EARR was influenced by the patient's age, treatment duration, treatment type, and periapical pathosis, but not by tooth type and sex. Root-filled teeth appear to be associated with significantly less EARR than are contralateral teeth with vital pulp. This study suggests that the possible complication of EARR in root-filled teeth may not be an important consideration in orthodontic treatment planning, and root canal treatment can be considered for stopping or decreasing EARR when severe EARR occurs during orthodontic treatment. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Application of laser speckle displacement analysis to clinical dentistry

NASA Astrophysics Data System (ADS)

Cumberpatch, G. K. D.; Hood, J. A. A.

1997-03-01

Success of dental restorations is dependent on the integrity of the tooth/restoration interface. Distortion of teeth due to operative procedures has previously been measured using LVDT's and strain-gauges and has provided useful but limited information. This paper reports on the verification of a system for laser speckle photography and its use to quantitative distortions in teeth from matrix band application and the use of bonded composite resin restorations. Tightening of matrix bands around teeth results in an inward deformation of the cusps, increasing incrementally as the band is tightened. Deflections of 50 micrometer/cusp were recorded. A delayed recovery was noted consistent with the viscoelastic behavior of dentine. For bonded restorations recovery will place the adhesion interface in a state of tension when the band is released and may cause premature failure. Premolar teeth restored with bonded resin restorations exhibited inward displacement of cusps of 12 - 15 micrometer. Deformation was not within the buccal-lingual axis as suggested by prior studies. Molar teeth bonded with composite resin restoration exhibit complex and variable cusp displacement in both magnitude (0 - 30 micrometer) and direction. Complete and partial debonding could be detected. Interproximal cusp bending could be quantitated and lifting of the restoration from the cavity floor was detectable. Deformations evidenced indicate the tooth/restoration interface is in a stressed state and this may subsequently lead to failure. The technique has the potential to aid in development of restoration techniques that minimize residual stress.

Selection and constraint underlie irreversibility of tooth loss in cypriniform fishes

PubMed Central

Aigler, Sharon R.; Jandzik, David; Hatta, Kohei; Uesugi, Kentaro; Stock, David W.

2014-01-01

The apparent irreversibility of the loss of complex traits in evolution (Dollo’s Law) has been explained either by constraints on generating the lost traits or the complexity of selection required for their return. Distinguishing between these explanations is challenging, however, and little is known about the specific nature of potential constraints. We investigated the mechanisms underlying the irreversibility of trait loss using reduction of dentition in cypriniform fishes, a lineage that includes the zebrafish (Danio rerio) as a model. Teeth were lost from the mouth and upper pharynx in this group at least 50 million y ago and retained only in the lower pharynx. We identified regional loss of expression of the Ectodysplasin (Eda) signaling ligand as a likely cause of dentition reduction. In addition, we found that overexpression of this gene in the zebrafish is sufficient to restore teeth to the upper pharynx but not to the mouth. Because both regions are competent to respond to Eda signaling with transcriptional output, the likely constraint on the reappearance of oral teeth is the alteration of multiple genetic pathways required for tooth development. The upper pharyngeal teeth are fully formed, but do not exhibit the ancestral relationship to other pharyngeal structures, suggesting that they would not be favored by selection. Our results illustrate an underlying commonality between constraint and selection as explanations for the irreversibility of trait loss; multiple genetic changes would be required to restore teeth themselves to the oral region and optimally functioning ones to the upper pharynx. PMID:24821783

Incidence of post-operative pain following single visit endodontics in vital and non-vital teeth: An in vivo study

PubMed Central

Bhagwat, Sumita; Mehta, Deepil

2013-01-01

This clinical study was conducted to compare the post-operative pain following single visit endodontics in vital and non-vital teeth, with and without periapical radiolucency. A total of 60 adult patients requiring root canal therapy in anterior and premolar teeth were selected for this study. Single sitting root canal treatment was carried out and the subjects were recalled after 2 weeks and instructed to fill out a series of self-report questionnaires for responses about pain in the interim after 1 day, 2 day, 3 day, 1 week and 2 weeks. In vital teeth (Group I) 60% of the treated cases had pain, of which 36% had mild pain (non-significant) and 24% had moderate pain (significant). In non-vital teeth without periapical radiolucency (Group II) 64% of cases had pain, of which 48% had mild pain (non-significant) and 16% had moderate pain (significant). In non-vital teeth with periapical radiolucency (Group III) 32% of the cases had pain of which 24% had mild pain (non-significant) and 8% had moderate pain (significant). None of the teeth in any of the groups had severe pain. There was no statistical difference between incidence of pain in vital and non-vital teeth without periapical radiolucency. Non-vital teeth with periapical radiolucency exhibited relatively less pain as compared with non-vital teeth without periapical radiolucency, but the pain continued in a significant percent of teeth even after 2 weeks. Pain incidence dropped significantly within a period of 1 day to 2 weeks in vital teeth and non-vital teeth without periapical radiolucency. There was a tendency for less incidence of significant pain after a single visit root canal treatment in these groups. Results obtained were comparable with those obtained by several investigators. PMID:24124293

Development of elements of the condition monitoring system of turbo generators of thermal power stations and nuclear power plants

NASA Astrophysics Data System (ADS)

Kumenko, A. I.; Kostyukov, V. N.; Kuz'minykh, N. Yu.; Boichenko, S. N.; Timin, A. V.

2017-08-01

The rationale is given for the improvement of the regulatory framework for the use of shaft sensors for the in-service condition monitoring of turbo generators and the development of control systems of shaft surfacing and misalignments of supports. A modern concept and a set of methods are proposed for the condition monitoring of the "shaft line-thrust bearing oil film-turbo generator supports" system elements based on the domestic COMPACS® technology. The system raw data are design, technology, installation, and operating parameters of the turbo generator as well as measured parameters of the absolute vibration of supports and mechanical quantities, relative displacements and relative vibration of the rotor teeth in accordance with GOST R 55263-2012. The precalculated shaft line assembly line in the cold state, the nominal parameters of rotor teeth positions on the dynamic equilibrium curve, the static and dynamic characteristics of the oil film of thrust bearings, and the shaft line stiffness matrix of unit support displacements have been introduced into the system. Using the COMPACS-T system, it is planned to measure positions and oscillations of rotor teeth, to count corresponding static and dynamic characteristics of the oil film, and the static and dynamic loads in the supports in real time. Using the obtained data, the system must determine the misalignments of supports and corrective alignments of rotors of coupling halves, voltages in rotor teeth, welds, and bolts of the coupling halves, and provide automatic conclusion if condition monitoring parameters correspond to standard values. A part of the methodological support for the proposed system is presented, including methods for determining static reactions of supports under load, the method for determining shaft line stiffness matrices, and the method for solving the inverse problem, i.e., the determination of the misalignments of the supports by measurements of rotor teeth relative positions in bearing housings. The procedure for calculating misalignments of turbo generator shaft line supports is set out.

Retention of Moisture-tolerant and Conventional Resin-based Sealant in Six- to Nine-year-old Children.

PubMed

Khatri, Sachin G; Samuel, Srinivasan Raj; Acharya, Shashidhar; Patil, Snehal; Madan, Kavita

2015-01-01

The purpose of this study was to evaluate and compare the retention rates and development of caries in permanent molars in children sealed with moisture-tolerant, resin-based (Embrace WetBond), and conventional resin-based (Helioseal) sealant over a period of one year. This was a double blind, split-mouth, randomized controlled trial among six- to nine-year-olds. Sixty-eight permanent mandibular first molars in 34 children were randomly assigned to be sealed with Embrace WetBond or Helioseal sealant. The final sample was 32 children with 64 teeth. At 12 months, 23 of 32 (72 percent) sealants were completely retained in Embrace WetBond, whereas only 16 of 32 (50 percent) were retained in the Helioseal group. There was a statistically significant difference in retention rates of Embrace WetBond and Helioseal sealants at 12 months (P<.05). At 12 months follow-up, only two teeth developed caries in Embrace WetBond; in the Helioseal group, five teeth developed caries (two initial and three enamel caries). Embrace WetBond was superior to Helioseal sealant, as Embrace exhibited higher retention and lower caries scores. Embrace WetBond can be preferred over conventional resin-based sealants for community and outreach sealant programs where use of rubber dam for moisture control is difficult to practice.

Autotransplantation of immature third molars using a computer-aided rapid prototyping model: a report of 4 cases.

PubMed

Jang, Ji-Hyun; Lee, Seung-Jong; Kim, Euiseong

2013-11-01

Autotransplantation of immature teeth can be an option for premature tooth loss in young patients as an alternative to immediately replacing teeth with fixed or implant-supported prostheses. The present case series reports 4 successful autotransplantation cases using computer-aided rapid prototyping (CARP) models with immature third molars. The compromised upper and lower molars (n = 4) of patients aged 15-21 years old were transplanted with third molars using CARP models. Postoperatively, the pulp vitality and the development of the roots were examined clinically and radiographically. The patient follow-up period was 2-7.5 years after surgery. The long-term follow-up showed that all of the transplants were asymptomatic and functional. Radiographic examination indicated that the apices developed continuously and the root length and thickness increased. The final follow-up examination revealed that all of the transplants kept the vitality, and the apices were fully developed with normal periodontal ligaments and trabecular bony patterns. Based on long-term follow-up observations, our 4 cases of autotransplantation of immature teeth using CARP models resulted in favorable prognoses. The CARP model assisted in minimizing the extraoral time and the possible Hertwig epithelial root sheath injury of the transplanted tooth. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Selection criteria of the addendum modification coefficients of spur gear pairs with smaller number of pinion teeth

NASA Astrophysics Data System (ADS)

Atanasiu, V.; Oprişan, C.; Leohchi, D.

2016-08-01

A design procedure for the optimum distribution of the addendum modification coefficients of spur gear pairs with smaller number of pinion teeth is presented for the case of a fixed centred distance. The geometrical, kinematics and load capacity criteria are considered in the design analysis. The geometric and kinematics criteria are used to prevent the negative phenomena of the generating and engagement processes. The relation between the contact pressure of meshing teeth and specific sliding are analysed in relation with addendum modification coefficients. A dynamic model is developed to simulate the load sharing characteristics through a mesh cycle. The specific phenomenon of contact tooth pairs alternation during mesh cycle is integrated in this dynamic load modelling. A comparative study is included, which shows the effects of the distribution factor of the addendum modification coefficients on the contact surface characteristics of the gear pairs.

Colour stability of denture teeth submitted to different cleaning protocols and accelerated artificial aging.

PubMed

Freire, T S; Aguilar, F G; Garcia, L da Fonseca Roberti; Pires-de-Souza, F de Carvalho Panzeri

2014-03-01

Acrylic resin is widely used for artificial teeth manufacturing due to several important characteristics; however, this material do not present acceptable colour stability over the course of time. This study evaluated the effect of different cleaning protocols and accelerated artificial aging on colour stability of denture teeth made of acrylic resin. Sixty denture teeth in dark and light shades were used, and separated according to the treatment to which they were submitted. Results demonstrated that colour stability of artificial teeth is influenced by the cleaning solution and artificial aging, being dark teeth more susceptible to colour alteration than lighter ones.

Targeted traction of impacted teeth with C-tube miniplates.

PubMed

Chung, Kyu-Rhim; Kim, Yong; Ahn, Hyo-Won; Lee, Dongjoo; Yang, Dong-Min; Kim, Seong-Hun; Nelson, Gerald

2014-09-01

Orthodontic traction of impacted teeth has typically been performed using full fixed appliance as anchorage against the traction force. This conventional approach can be difficult to apply in the mixed dentition if the partial fixed appliance offers an insufficient anchor unit. In addition, full fixed appliance can induce unwanted movement of adjacent teeth. This clinical report presents 3 cases where impacted teeth were recovered in the mixed or transitional dentition with skeletal anchorage on the opposite arch without full fixed appliance. Instead, intermaxillary traction was used to bring the impacted teeth into position. With this approach, side effects on teeth and periodontal tissues adjacent to the impaction were minimized.

Endoscopic root canal treatment.

PubMed

Moshonov, Joshua; Michaeli, Eli; Nahlieli, Oded

2009-10-01

To describe an innovative endoscopic technique for root canal treatment. Root canal treatment was performed on 12 patients (15 teeth), using a newly developed endoscope (Sialotechnology), which combines an endoscope, irrigation, and a surgical microinstrument channel. Endoscopic root canal treatment of all 15 teeth was successful with complete resolution of all symptoms (6-month follow-up). The novel endoscope used in this study accurately identified all microstructures and simplified root canal treatment. The endoscope may be considered for use not only for preoperative observation and diagnosis but also for active endodontic treatment.

Minimally Invasive Dentistry: A Conservative Approach to Smile Makeover.

PubMed

Rosenberg, Jeffrey M

2017-01-01

The concept of minimally invasive dentistry is based on preserving tooth structure, especially enamel. A conservative method to treat discolored teeth that have diastemas is a freehand additive technique using composite resin. While selecting the correct shade of resin can be challenging, newer composite resin formulations are being developed with optical properties that enable the material to more effectively blend into the dentition. This case report describes the use of conservative approaches and materials to treat discolored, unevenly spaced teeth and restore harmony and balance to a patient's smile.

Oral Rehabilitation of a Patient with Amelogenesis Imperfecta

PubMed Central

Cogulu, Dilsah; Becerik, Sema; Emingil, Gülnur; Hart, P. Suzanne; Hart, Thomas C.

2014-01-01

Amelogenesis imperfecta is a hereditary disorder that causes defective enamel development in the primary and permanent teeth. Clinical treatment is important to address the esthetic appearance of affected teeth, reduce dentinal sensitivity, preserve tooth structure, and optimize masticatory function. The purpose of this case report was to describe the diagnosis, treatment planning, and dental rehabilitation of a patient with autosomal recessive amelogenesis imperfecta. The patient was followed for 5 years, and evaluation 3 years after restorations revealed no pathology associated with the rehabilitation. The patient’s esthetic and functional expectations were satisfied. PMID:20108745

Distribution of bacterial morphotypes around natural teeth and titanium implants ad modum Brånemark.

PubMed

Quirynen, M; Listgarten, M A

1990-12-01

The subgingival plaque around both teeth and implants was analysed by means of differential phase-contrast microscopy. It was noted that, in comparison to natural teeth, the subgingival samples from implants were more frequently too small to provide adequate bacterial counts. In 24 partially edentulous patients (with implants and teeth in the same jaw), no significant differences in the distribution of bacterial morphotypes could be found between implants and natural teeth. The %s of coccoid cells, motile rods, spirochetes and other bacteria were 65.8, 2.3, 2.1, and 29.8 for implants and 55.6, 4.9, 3.6, and 34.9 for teeth, respectively. However, when the plaque composition on the implants of fully edentulous patients was compared with those of teeth or implants of partially edentulous patients (with teeth and implants in the same and/or opposite jaw), significant differences appeared. In fully edentulous patients, more coccoid cells (71.3%) and significant fewer motile rods (0.4%) and spirochetes (0.0) were found around the implants. The results suggest that teeth may serve as a reservoir for the bacterial colonisation of titanium implants in the same mouth.

Anesthetic efficacy of the supplemental intraosseous injection for teeth with irreversible pulpitis.

PubMed

Parente, S A; Anderson, R W; Herman, W W; Kimbrough, W F; Weller, R N

1998-12-01

The purpose of this study was to determine the efficacy of a supplemental intraosseous injection (IOI) of 2% lidocaine with 1:100,000 epinephrine using the Stabident device, after conventional anesthetic methods had failed. Patients who experienced pain during endodontic access and required a supplemental IOI using 0.45 to 0.90 ml of the local anesthetic were identified. All 37 of the patients treated had teeth diagnosed with irreversible pulpitis. Thirty-four of the teeth were mandibular posterior teeth, 2 were maxillary posterior teeth, and 1 was a maxillary anterior tooth. Patients with maxillary teeth had received infiltration anesthesia, and those with mandibular teeth had received an inferior alveolar nerve block in conjunction with long buccal infiltration. A minimum of 3.6 ml of local anesthetic was used with the conventional techniques. Modified visual analogue scales, coupled with operator evaluations, were used to measure success. The Stabident IOI was an effective supplemental anesthetic technique in 89% (+/- 5.1) or 33/37 patients evaluated. The 95% confidence interval was 74 to 97%. The IOI was successful in 91% (+/- 4.9) of the mandibular posterior teeth (31/34), and 67% of the maxillary teeth (2/3).

Association between anticonvulsant drugs and teeth-grinding in children and adolescents with cerebral palsy.

PubMed

Ortega, A O L; Dos Santos, M T B R; Mendes, F M; Ciamponi, A L

2014-09-01

The relation between teeth-grinding and the use of drugs acting on the central nervous system of cerebral palsy (CP) patients has not yet been described. The aim of this research was to evaluate the presence or absence of teeth-grinding (sleep and/or awake periods) in normal and in CP children and adolescents, as well as the association of teeth-grinding and use of anticonvulsant drugs. The sample consisted of 207 children and adolescents, divided into three groups: G1, individuals with CP who did not take anticonvulsant drugs; G2, individuals with CP administered medications on a regular basis; and CG, normal individuals. Logistic regression analyses were performed to evaluate the association of teeth-grinding with some variables. No significant statistical differences were observed regarding the presence or absence of teeth-grinding when G1 and G2 were compared. However, compared with the CG, a statistically significant difference was determined, with the CG showing fewer children presenting teeth-grinding (P < 0·001). Among those children/adolescents prescribed drug therapy, the barbiturate group showed a greater frequency of teeth-grinding. CP children and adolescents show a greater and significant presence of grinding of the teeth compared with normal individuals. Subjects taking barbiturate drugs showed greater presence of teeth-grinding, than those who were taking medications from the other groups of anticonvulsant drugs. © 2014 John Wiley & Sons Ltd.

Root length in the permanent teeth of women with an additional X chromosome (47,XXX females).

PubMed

Lähdesmäki, Raija E; Alvesalo, Lassi J

2010-07-01

Previous studies have demonstrated differential effects of the X and Y chromosomes on dental development. The expression of sexual dimorphism in terms of tooth size, shape, number and developmental timing has been explained especially by Y chromosome influence. The Y chromosome promotes enamel, crown and root dentin development. The X chromosome has an effect on enamel deposition. The aim of this research is to study the influence of the extra X chromosome on the development of permanent tooth root length. The study subjects (all of whom were from the Kvantti Dental Research Project) were seven 47,XXX females, five female relatives and 51 and 52 population control men and women, respectively. Measurements were made from panoramic radiographs on available permanent teeth by a digital calliper according to established procedures. The results showed that the maxillary root lengths of the 47,XXX females were of the same magnitude as those in normal women, but the mandibular root lengths were longer in 47,XXX females than in normal men or women. Increased enamel thickness in the teeth of 47,XXX females is apparently caused by the active enamel gene in all X chromosomes having no increased influence on crown dentin formation. These results in 47,XXX females indicate an increase in root dentin development, at least in the mandible, which together with the data on crown formation reflects a continuous long-lasting effect of the X chromosome on dental development.

[DNA extraction from bones and teeth using AutoMate Express forensic DNA extraction system].

PubMed

Gao, Lin-Lin; Xu, Nian-Lai; Xie, Wei; Ding, Shao-Cheng; Wang, Dong-Jing; Ma, Li-Qin; Li, You-Ying

2013-04-01

To explore a new method in order to extract DNA from bones and teeth automatically. Samples of 33 bones and 15 teeth were acquired by freeze-mill method and manual method, respectively. DNA materials were extracted and quantified from the triturated samples by AutoMate Express forensic DNA extraction system. DNA extraction from bones and teeth were completed in 3 hours using the AutoMate Express forensic DNA extraction system. There was no statistical difference between the two methods in the DNA concentration of bones. Both bones and teeth got the good STR typing by freeze-mill method, and the DNA concentration of teeth was higher than those by manual method. AutoMate Express forensic DNA extraction system is a new method to extract DNA from bones and teeth, which can be applied in forensic practice.

The effect of long-term disinfection procedures on hardness property of resin denture teeth.

PubMed

Campanha, Nara Hellen; Pavarina, Ana Cláudia; Jorge, Janaina Habib; Vergani, Carlos Eduardo; Machado, Ana Lucia; Giampaolo, Eunice Teresinha

2012-06-01

The aim of the study was to evaluate the effect of long-term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth. Five acrylic resin denture teeth (Vipi Dent Plus-V, Trilux-T, Biolux-B, Postaris-P and Artiplus-A) and one composite resin denture teeth (SR-Orthosit-O) were embedded in heat-polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01). Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p < 0.001). Immersion for 7 days in 4% chlorhexidine gluconate or distilled water had significant effect on the hardness of the acrylic resin denture teeth A (p < 0.01), and 1% sodium hypochlorite on teeth T (p < 0.01). All disinfection procedures decrease the hardness of the composite resin denture teeth (p < 0.01). Teeth O exhibited the highest and teeth V the lowest hardness values in the control group (p < 0.01). Disinfection procedures changed the hardness of resin denture teeth. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Open bite as a risk factor for orthodontic root resorption.

PubMed

Motokawa, Masahide; Terao, Akiko; Kaku, Masato; Kawata, Toshitsugu; Gonzales, Carmen; Darendeliler, M Ali; Tanne, Kazuo

2013-12-01

The purpose of the present study was to clarify the prevalence and degree of root resorption induced by orthodontic treatment in patients with and without open bite. One hundred and eleven patients treated with multibracket appliances were retrospectively selected from the patients and divided into non-open bite (NOB) and open bite (OB) groups. The severity of root resorption and the root shape were classified into five groups on periapical radiographs before and after treatment. Moreover, only in the OB group, all teeth were sub-divided into functional and hypofunctional ones that are occluding and non-occluding. As the results of multiple linear regression analysis of patient characteristics and clinical variables with the number of overall root resorption, the independent variables that were found to contribute significantly to root resorption were bite and abnormal root shape. The prevalences of root resorption evaluated in the number of patients were significantly higher in OB group than in NOB group, and those in the number of teeth were significantly higher in OB group than in NOB group, in particular anterior and premolar teeth. The prevalence of resorbed teeth with abnormal root shapes was also significantly higher in OB group than in NOB group. On the other hand, in OB group, the prevalences of root resorption and teeth with abnormal root shape were significantly greater in hypofunctional teeth than in normal functional teeth. There are more teeth with root resorption and abnormal root shape in open bite cases than in normal bite cases, and more teeth with abnormal root shapes and root resorption in hypofunctional teeth than in functional teeth.

21 CFR 872.5550 - Teething ring.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Teething ring. 872.5550 Section 872.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5550 Teething ring. (a) Identification. A teething ring is a...

A 57-year follow-up study of occlusion. Part 3: Oral health and attitudes to teeth among individuals with crossbite at the age of 8 years.

PubMed

Berg, Rolf Elling; Espeland, Lisen; Stenvik, Arild

2008-11-01

To analyze occlusal changes occurring between the ages of 8 and 65 years in persons with anterior and/or posterior crossbite at the age of 8; to examine their attitudes toward dental appearance and their experiences related to their own teeth. Of the 81 people we contacted who had been documented as having crossbite as 8-year-olds in 1950, 21 agreed to participate in this follow-up study. Their occlusal conditions had been documented initially by intraoral photographs in 1950, and a clinical examination including facial photographs, further occlusal photographs and an interview took place in 2007. For comparison, we also had available similarly-documented examples of individuals (n = 18) of the same age and with normal occlusion in 1950. Oral hygiene was good or excellent in all individuals and all but one visited their dentist regularly. The average number of missing teeth was 3.8, whereas in the normal occlusion sample that number was 1.6. Of the eight persons who had undergone minor orthodontic treatment during childhood, five had an anterior crossbite resolved. Four persons who had initially presented a posterior crossbite later developed an anterior crossbite as well. In 2007, eleven individuals had a posterior and eight an anterior crossbite. At 65, four persons remembered that they had been teased in childhood because of their teeth, and could still remember the terms that had been used. Eighteen persons were satisfied with their teeth although two had severe anterior crossbite; three were dissatisfied, and their reasons were general health problems, mild crowding, and dentofacial asymmetry. Seven persons had TMJ symptoms with various types of history. With three exceptions, they all considered good tooth position to be important or very important. In those not orthodontically treated, malocclusion tended to worsen, although 18 of the 21 persons expressed satisfaction with their teeth as adults. They had a higher average number of missing teeth, and more had TMJ problems than the control group with normal occlusion.

The owner-animal-environment triad in the treatment of canine periodontal disease.

PubMed

Hale, Fraser A

2003-06-01

In a perfect world, all veterinarians and veterinary dental technicians would understand periodontal disease as well as the dental specialist. They would all be able to recognize the early signs of periodontal disease and recommend treatment to prevent its progression. The owners would have the financial resources, time, and desire to maintain their pet's oral health. The dogs would all be calm and compliant with home care and have no particular anesthetic risks. Unfortunately, this is not a perfect world. Some veterinarians do not understand periodontal disease any better that I understand cosmic string theory. Some owners have limited financial resources and are not particularly committed to their pet's oral health. Some animals will not tolerate any type or manner of home care. Given that animals, their mouths, and their owners come in an infinite variety of shapes and sizes (figuratively and literally), how can we talk about the treatment of periodontal disease as if it is a single condition with a single treatment, or even only a few treatment options? Each owner, animal, and its environment must be assessed on an individual basis to develop a treatment plan that is reasonable and attainable based on the unique circumstances of each case. So, what should be the goal when treating periodontal disease? Is it the preservation of all teeth at all costs? Is it the preservation of important teeth if the costs can be kept reasonable? I would suggest that the overriding goal of periodontal treatment should be the elimination and prevention of oral infection and oral pain. In the domestic environment, dogs have no real need to defend territory. They have no need to prehend and kill live prey animals. In short, the domesticated pet dog does not need teeth at all. This may seem like an odd statement for a veterinary dentist to make, but I feel quite strongly that a dog is far better off having no teeth than having bad teeth. My preference is that a dog should have a full set of healthy, functional teeth, but preserving bad teeth in the face of a poor or questionable prognosis serves no positive purpose.

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth.

PubMed

Lin, Hung-Pin; Tu, Han-Ping; Hsieh, Yu-Ping; Lee, Bor-Shiunn

2017-01-01

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide- co -glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA-lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV-Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA-lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA-lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA-lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA-lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA-lovastatin (100 μg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA-lovastatin (100 μg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA-lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA-lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.

Absence of αvβ6 Integrin Is Linked to Initiation and Progression of Periodontal Disease

PubMed Central

Ghannad, Farzin; Nica, Daniela; Garcia Fulle, Maria I.; Grenier, Daniel; Putnins, Edward E.; Johnston, Sarah; Eslami, Ameneh; Koivisto, Leeni; Jiang, Guoqiao; McKee, Marc D.; Häkkinen, Lari; Larjava, Hannu

2008-01-01

Integrin αvβ6 is generally not expressed in adult epithelia but is induced in wound healing, cancer, and certain fibrotic disorders. Despite this generalized absence, we observed that αvβ6 integrin is constitutively expressed in the healthy junctional epithelium linking the gingiva to tooth enamel. Moreover, expression of αvβ6 integrin was down-regulated in human periodontal disease, a common medical condition causing tooth loss and also contributing to the development of cardiovascular diseases by increasing the total systemic inflammatory burden. Remarkably, integrin β6 knockout mice developed classic signs of spontaneous, chronic periodontal disease with characteristic inflammation, epithelial down-growth, pocket formation, and bone loss around the teeth. Integrin αvβ6 acts as a major activator of transforming growth factor-β1 (TGF-β1), a key anti-inflammatory regulator in the immune system. Co-expression of TGF-β1 and αvβ6 integrin was observed in the healthy junctional epithelium. Moreover, an antibody that blocks αvβ6 integrin-mediated activation of TGF-β1 initiated inflammatory periodontal disease in a rat model of gingival inflammation. Thus, αvβ6 integrin is constitutively expressed in the epithelium sealing the gingiva to the tooth and plays a central role in protection against inflammatory periodontal disease through activation of TGF-β1. PMID:18385522

Supernumerary Teeth in Primary Dentition and Early Intervention: A Series of Case Reports

PubMed Central

Bahadure, Rakesh N.; Thosar, Nilima; Jain, Eesha S.; Kharabe, Vidhi; Gaikwad, Rahul

2012-01-01

Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stages. They are of great concern to the dentists and parents because of the eruption, occlusal, and esthetic problems they can cause. Supernumerary teeth occur more frequently in the permanent dentition but rarely in primary dentition. Mesiodens is the most common type of supernumerary teeth but rarely seen in lower arch. Early recognition and diagnosis of supernumerary teeth is important to prevent further complications in permanent dentition. Four cases of supernumerary teeth with mesiodens in upper and lower arch in primary dentition and their management have been discussed. PMID:22888456

Clinical and radiographic evaluation of one- and two-visit endodontic treatment of asymptomatic necrotic teeth with apical periodontitis: a randomized clinical trial.

PubMed

Molander, Anders; Warfvinge, Johan; Reit, Claes; Kvist, Thomas

2007-10-01

The present investigation recorded the 2-year clinical and radiographic outcome of one- and two visit endodontic treatment and studied the significance of the bacteriologic sampling results on the outcome. A randomization procedure allocated 53 teeth to one-visit treatment and 48 teeth to two-visit treatment. At the end of the study period, 32 teeth (65%) in the one-visit group and 30 teeth (75%) in the two-visit group were classified as healed. The statistical analysis of the healing results did not show any significant difference between the groups (p = 0.75). Forty-nine (80%) of the 61 teeth that were obturated after a negative micobiologic sample were classified as healed. Teeth sealed after positive samples healed in 44%. The present study gave evidence that similar healing results might be obtained through one- and two-visit antimicrobial treatment.

Combined Orthodontic-surgical Treatment for Skeletal Class III Malocclusion with Multiple Impacted Permanent and Supernumerary Teeth: Case Report.

PubMed

Xue, Dai Juan And Feng

2014-01-01

In this report we describe a combined orthodontic and surgical treatment for a 14-year-old boy with severe skeletal class III deformity and dental problem. His upper posterior primary teeth in the left side were over-retained and 6 maxillary teeth (bilateral central incisors and canines, left first and second premolars) were impacted, together with 5 supernumerary teeth in both arches. The treatment protocol involved extraction of all the supernumerary and deciduous teeth, surgical exposure and orthodontic traction of the impacted teeth, a bimaxillary orthognathic approach including Lefort I osteotomy. Bilateral sagittal split ramus osteotomy (BSSRO) and genioplasty was performed to correct skeletal problem. After treatment, all of the impacted teeth were brought to proper alignment in the maxillary arch. A satisfied profile and good posterior occlusion was achieved. Treatment mechanics and consideration during different stages are discussed.

Autotransplantation donor tooth site harvesting using piezosurgery.

PubMed

Ylikontiola, Leena P; Sándor, George K

2016-01-01

The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes.

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

A Curriculum Vitae of Teeth: Evolution, Generation, Regeneration

PubMed Central

Koussoulakou, Despina S.; Margaritis, Lukas H.; Koussoulakos, Stauros L.

2009-01-01

The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration. PMID:19266065

Study on stability of rake teeth inserting soil of chain rake type mulching film recovery machine based on Adams

NASA Astrophysics Data System (ADS)

Guo, Wensong; Jian, Jianming; San, Yunlong; Lui, Rui; Li, Gang; Hou, Shulin

2017-08-01

Traditional rake type mulching film recycling machine has the problem of difficulty in unloading and packing film, poor continuity of the work. In order to solve such problems, this paper designs a kind of chain rake type mulching film recycling machine which can realize continuous raking film, collecting film, transporting film, shaking off soil, unloading film. Rake teeth is the basic part of chain rake mulching recycling machine. The stability of rake teeth's inserting soil is an important factor to ensure recovery efficiency of the plastic film recovery. By virtual prototype simulation, this paper study the influence of different factors on the stability of rake teeth inserting soil. The results are as follows: The speed of chain rake has no significant effect on the stability of rake teeth inserting soil; Reducing resistance of rake teeth in the process of working, is conducive to improve the stability of rake teeth inserting soil; Appropriate increasing elastic modulus of chain rake, is helpful to enhance the stability of rake teeth inserting soil.

Periodontal response to all-ceramic crowns (IPS Empress) in general practice.

PubMed

Al-Wahadni, A M; Mansour, Y; Khader, Y

2006-02-01

The purpose of this study was to investigate the periodontal response to the presence of all-ceramic crowns (IPS Empress) in general practice patients. The convenience sample included 82 IPS Empress crowns placed in 64 patients. These crowns had been in place for an average of 16.27 (SD 9.26) months and ranged from 6.2 to 48.87 months at the time of clinical examination. Periodontal health status (as determined by dental plaque, gingival health status, periodontal pockets) was assessed around all crowned teeth and around matched contralateral teeth by one calibrated examiner. Periodontal indices utilized included the Plaque Index (PI), Gingival Index (GI) and pocket depth (PD) with calibrated probes graduated in millimetres. Plaque, gingival and PD values for crowned teeth were compared with those for control teeth using Wilcoxon signed-rank test for each clinical parameters. Chi-square was used to test the significance of the difference in their distribution between crowns and control teeth. Statistically, PI (0.35), GI (0.41) and mean PD scores (1.42) of IPS Empress crowned teeth compared less favourably with scores of the control teeth (0.27, 0.23 and 0.86 respectively). Teeth with IPS Empress crowns had poorer periodontal health and more clinically evident plaque than uncrowned teeth.

The prevalence of dental anomalies in the Western region of saudi arabia.

PubMed

Afify, Ahmed R; Zawawi, Khalid H

2012-01-01

Objective. The aim of this cross-sectional study was to investigate the prevalence of dental anomalies that could be a cause of malocclusion in the western region of Saudi Arabia. Materials and Methods. A retrospective study of 878 digital orthopantomograms (OPGs) taken of patients, age ranging between 12 and 30 years, who presented to treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia between 2002 and 2011. The OPGs and dental records were reviewed for congenitally missing teeth, supernumerary teeth, impactions, ectopic eruption, transposition, germination, fusion, dilacerations, taurodontism, dens in dent, and any other unusual conditions that can be assessed with OPG. Results. The prevalence of patient that exhibited at least one dental anomaly was 396 (45.1%) patients. The prevalence of congenitally missing teeth was 226 (25.7%), impacted teeth 186 (21.1%), dilacerated teeth 10 (1.1%), supernumerary teeth 3 (0.3%), odontoma 1 (0.1%), and taurodontism was also 1 case (0.1%) of the total radiographs reviewed. Conclusions. Congenitally missing teeth were found to be the most prevalent anomaly (25.7%), and the second frequent anomaly was impacted teeth (21.1%), whereas root dilacerations, supernumerary teeth, and taurodontism were the least frequent anomalies (1.1%, 0.3% and 0.1%, resp.).

A construction of standardized near infrared hyper-spectral teeth database: a first step in the development of reliable diagnostic tool for quantification and early detection of caries

NASA Astrophysics Data System (ADS)

Bürmen, Miran; Usenik, Peter; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

2011-03-01

Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentin and pulp. If left untreated, the disease can lead to pain, infection and tooth loss. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Several papers reported on near infrared (NIR) spectroscopy to be a potentially useful noninvasive spectroscopic technique for early detection of caries lesions. However, the conducted studies were mostly qualitative and did not include the critical assessment of the spectral variability of the sound and carious dental tissues and influence of the water content. Such assessment is essential for development and validation of reliable qualitative and especially quantitative diagnostic tools based on NIR spectroscopy. In order to characterize the described spectral variability, a standardized diffuse reflectance hyper-spectral database was constructed by imaging 12 extracted human teeth with natural lesions of various degrees in the spectral range from 900 to 1700 nm with spectral resolution of 10 nm. Additionally, all the teeth were imaged by digital color camera. The influence of water content on the acquired spectra was characterized by monitoring the teeth during the drying process. The images were assessed by an expert, thereby obtaining the gold standard. By analyzing the acquired spectra we were able to accurately model the spectral variability of the sound dental tissues and identify the advantages and limitations of NIR hyper-spectral imaging.

Assessment of Demirjian's 8-teeth technique of age estimation and Indian-specific formulas in an East Indian population: A cross-sectional study.

PubMed

Rath, Hemamalini; Rath, Rachna; Mahapatra, Sandeep; Debta, Tribikram

2017-01-01

The age of an individual can be assessed by a plethora of widely available tooth-based techniques, among which radiological methods prevail. The Demirjian's technique of age assessment based on tooth development stages has been extensively investigated in different populations of the world. The present study is to assess the applicability of Demirjian's modified 8-teeth technique in age estimation of population of East India (Odisha), utilizing Acharya's Indian-specific cubic functions. One hundred and six pretreatment orthodontic radiographs of patients in an age group of 7-23 years with representation from both genders were assessed for eight left mandibular teeth and scored as per the Demirjian's 9-stage criteria for teeth development stages. Age was calculated on the basis of Acharya's Indian formula. Statistical analysis was performed to compare the estimated and actual age. All data were analyzed using SPSS 20.0 (SPSS Inc., Chicago, Illinois, USA) and MS Excel Package. The results revealed that the mean absolute error (MAE) in age estimation of the entire sample was 1.3 years with 50% of the cases having an error rate within ± 1 year. The MAE in males and females (7-16 years) was 1.8 and 1.5, respectively. Likewise, the MAE in males and females (16.1-23 years) was 1.1 and 1.3, respectively. The low error rate in estimating age justifies the application of this modified technique and Acharya's Indian formulas in the present East Indian population.

Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates.

PubMed

Smith, Timothy D; Muchlinski, Magdalena N; Jankord, Kathryn D; Progar, Abbigal J; Bonar, Christopher J; Evans, Sian; Williams, Lawrence; Vinyard, Christopher J; Deleon, Valerie B

2015-12-01

In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate. © 2015 Wiley Periodicals, Inc.

Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates

PubMed Central

Smith, Timothy D.; Muchlinksi, Magdalena N.; Jankord, Kathryn D.; Progar, Abbigal J.; Bonar, Christopher J.; Evans, Sian; Williams, Lawrence; Vinyard, Christopher J.; DeLeon, Valerie B.

2015-01-01

In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate. PMID:26425925

Prenatal metal exposure in the Middle East: imprint of war in deciduous teeth of children.

PubMed

Savabieasfahani, M; Ali, S Sadik; Bacho, R; Savabi, O; Alsabbak, M

2016-09-01

In war zones, the explosion of bombs, bullets, and other ammunition releases multiple neurotoxicants into the environment. The Middle East is currently the site of heavy environmental disruption by massive bombardments. A very large number of US military bases, which release highly toxic environmental contaminants, have also been erected since 2003. Current knowledge supports the hypothesis that war-created pollution is a major cause of rising birth defects and cancers in Iraq. We created elemental bio-imaging of trace elements in deciduous teeth of children with birth defects from Iraq. Healthy and naturally shed teeth from Lebanon and Iran were also analyzed for trace elements. Lead (Pb) was highest in teeth from children with birth defects who donated their teeth from Basra, Iraq (mean 0.73-16.74 (208)Pb/(43)Ca ppm, n = 3). Pb in healthy Lebanese and Iranian teeth were 0.038-0.382 (208)Pb/(43)Ca ppm (n = 4) and 0.041-0.31 (208)Pb/(43)Ca ppm (n = 2), respectively. Our hypothesis that increased war activity coincides with increased metal levels in deciduous teeth is confirmed by this research. Lead levels were similar in Lebanese and Iranian deciduous teeth. Deciduous teeth from Iraqi children with birth defects had remarkably higher levels of Pb. Two Iraqi teeth had four times more Pb, and one tooth had as much as 50 times more Pb than samples from Lebanon and Iran.

Further Treatments of Root-filled Teeth in the Swedish Adult Population: A Comparison of Teeth Restored with Direct and Indirect Coronal Restorations.

PubMed

Dawson, Victoria S; Isberg, Per-Erik; Kvist, Thomas; Fransson, Helena

2017-09-01

The aim of this study was to evaluate the frequencies of nonsurgical retreatment, root-end surgery, extraction, and further restoration of root-filled teeth in Sweden in 2009 during a follow-up period of 5 years and to compare the outcomes in teeth restored with direct or indirect restorations. Data from the Swedish Social Insurance Agency were analyzed, and the frequencies of nonsurgical retreatment, root-end surgery, extractions, and further restoration were calculated for all teeth registered as root filled during 2009. Chi-square tests were applied to detect any significant differences in the frequency of further treatment in teeth registered as restored with either a direct or an indirect restoration within 6 months of root filling. Of the 248,299 teeth reported root filled in Sweden in 2009, nonsurgical retreatment was registered in 2.2%, root-end surgery in 1.0%, and extractions in 9.2% during the follow-up period. Of the teeth restored with a direct restoration within 6 months after the root filling, 30.3% were registered as having undergone at least 1 further direct restoration; the corresponding percentage of teeth with indirect restorations was 6.4%. A statistically significant difference in the frequency of nonsurgical retreatment, extraction, and further restoration was found; teeth restored with an indirect restoration within 6 months of root filling had fewer of these treatments than those restored by direct restoration. Low frequencies of nonsurgical retreatment and root-end surgery were reported 5 years after root filling, whereas extraction was more common. Fewer additional treatment procedures were registered for teeth with indirect restorations than for those with direct restorations. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.