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Sample records for bovine permanent teeth

  1. Dental fluorosis in bovine temporary teeth

    SciTech Connect

    Suttie, J.W.; Clay, A.B.; Shearer, T.R.

    1985-02-01

    Deciduous incisors from calves born to dams fed an average of 40 mg of fluoride/kg of forage ration (40 ppm) were compared with incisors from calves born to dams fed a normal dairy ration. Skeletal fluoride concentration in the calves born to fluoride-fed dams was increased 5 to 8 fold, but enamel mottling and hypoplasia, typical of permanent bovine incisor dental fluorosis were not seen by gross, histologic, or radiologic examination. Decreases in the amount of enamel on the tooth or hardness of the enamel were not observed. These data do not support recent reports of widespread dental fluorosis of deciduous bovine teeth as a clinical sign of fluoride toxicity.

  2. Radiodensity and hardness of enamel and dentin of human and bovine teeth, varying bovine teeth age.

    PubMed

    Fonseca, R B; Haiter-Neto, F; Carlo, H L; Soares, C J; Sinhoreti, M A C; Puppin-Rontani, R M; Correr-Sobrinho, L

    2008-11-01

    Studies have evaluated dental hard tissues characteristics from animal species in order to be used as a substitute for human teeth. The aim of this study was to evaluate the radiodensity and hardness of human and bovine enamel and dentin, varying bovine teeth age. Five specimens (1mm thick) were obtained from animals aged 20 (B20), 30 (B30), 38 (B38) and 48 (B48)months and from 20 to 30-years-old human third molars (H). The radiographic images were taken with a phosphor plaque digital system (Digora Optime). The radiodensity was obtained and Knoop hardness (KHN) was recorded (100g for 15s--5 indentations per specimen). Data were analyzed by one-way ANOVA following Tukey's HSD test and Dunnet's two-sided t-test. Radiodensity was similar within enamel groups, but bovine dentin presented higher radiodensity than human one regardless of age groups. Enamel-KHN showed differences between B20-B30 and B38-B48-H, and dentin-KHN was similar within all groups. Enamel was always more radiodense than dentin and also presented higher KHN (p=0.001). The use of bovine enamel or dentin should take into consideration the teeth age, but as a general rule it should be recommended to select older bovine teeth due to better chances to find greater similarity with human teeth.

  3. Characterization of primary and permanent teeth using terahertz spectroscopy

    PubMed Central

    Yetimoĝlu, N Ö; Altan, H

    2014-01-01

    Objectives: To analyse teeth samples by using terahertz time-domain spectroscopy (THz-TDS) system that was developed in the laboratory to measure the properties of sliced teeth sections in transmission mode. Methods: Using home-built THz-TDS system, we analysed a total of 25 teeth samples (9 primary and 16 permanent teeth). For transmission measurements, the refractive index and absorptive properties of the teeth sections were calculated. Difference between groups was tested using Mann–Whitney U-test statistics at the specific frequency of 0.5 THz, which was at the midpoint of the bandwidth. Median and minimum–maximum values were given as descriptive statistics. Type-I error rate was taken as α = 0.05. Results: Median refractive index values for permanent and primary teeth were found to be 2.53 and 2.54, respectively. Median absorption coefficient values for permanent and primary teeth were found to be 26.29 and 29.67, respectively. Median refractive index values for both healthy and carious teeth were found to be 2.54. Median absorption coefficient values for healthy and carious teeth were found to be 26.52 and 27.13, respectively. Although higher median absorption coefficient values were found for primary and carious teeth than those of permanent and healthy teeth, the differences were insignificant (p > 0.05). In addition, no statistical differences were found for refractive index values among different groups (p > 0.05). Conclusions: THz imaging has the potential to be used in assessing dental structures. PMID:24940807

  4. The effects of impacted premaxillary supernumerary teeth on permanent incisors

    PubMed Central

    Jung, Yun-Hoa; Kim, Ji-Yeon

    2016-01-01

    Purpose The aim of this study was to examine the radiographic features associated with impacted premaxillary supernumerary teeth, to determine the relationship between their characteristics and their effects on permanent incisors, and to investigate the types of orthodontic treatment that patients received after the extraction of impacted supernumerary teeth. Materials and Methods The clinical records and radiographs of 193 patients whose impacted premaxillary supernumerary teeth were removed were retrospectively reviewed, and 241 impacted supernumerary teeth were examined. Cone-beam computed tomographic images and panoramic radiographs were examined to determine the number, location, sagittal position, orientation, and morphology of the supernumerary teeth. Their effects on permanent incisors and the orthodontic treatment received by patients after the extraction of the supernumeraries were also investigated. Results Supernumerary teeth were most frequently observed in the central incisor region, in the palatal position, in the inverted orientation, and were most commonly conical in shape. The most common complication was median diastema, followed by displacement and delayed eruption of the adjacent incisors. Ten (71.4%) of the 14 odontomas showed delayed eruption of the adjacent incisors. Displacement of the incisors was more frequently observed in association with supernumerary teeth with tuberculate or supplemental shapes. Orthodontic traction was most frequently performed after the removal of odontomas. In 32 cases (13.3%), permanent incisors erupted after the orthodontic creation of sufficient space. Conclusion Median diastema was most common complication. The delayed eruption of incisors was common in supernumerary teeth with a vertical orientation and an odontoma shape. PMID:28035303

  5. Partial pulpotomy in young permanent teeth with deep carious lesions.

    PubMed

    Mejàre, I; Cvek, M

    1993-12-01

    The material comprised 37 young posterior teeth with deep carious lesions and exposed pulps, treated with partial pulpotomy and dressed with calcium hydroxide. The teeth were divided into two groups. Group 1 consisted of 31 teeth with no clinical or radiographic symptoms before treatment, Group 2 of 6 teeth with temporary pain, widened periodontal space periapically and/or productive osteitis, i.e. increased density of the surrounding alveolar bone. After an observation time of 24 to 140 months (mean = 56 months), healing had occurred in 29 of 31 teeth in Group 1 (93.5%) and in 4 of 6 teeth in Group 2. It was concluded that the present, as well as previously reported results indicate that partial pulpotomy may be an adequate treatment for young permanent molars with a carious exposure, although more studies are needed before the treatment can be recommended for routine clinical use.

  6. Bovine teeth as substitute for human teeth in dental research: a review of literature.

    PubMed

    Yassen, Ghaeth H; Platt, Jeffrey A; Hara, Anderson T

    2011-09-01

    The aim of this paper was to review in vitro and in situ studies that directly compared the use of bovine teeth as a substitute for human teeth in dental experiments. A PubMed search was conducted for papers published from 1953 to December 30, 2010 using the following keywords: "human bovine enamel" or "human bovine dentin" or "human bovine teeth". The abstracts of the studies resulting from the keyword search were read, and all papers that compared human and bovine teeth were fully read. Only original articles written in English and directly comparing human and bovine substrates were included in the review. The search was supplemented by manual searches of the reference lists from each identified paper. Out of 76 studies initially selected, 68 fulfilled the selection criteria for inclusion. The studies covered seven categories: dental morphology, chemical composition, physical properties, dental caries, dental erosion/abrasion, bonding/adhesive strength, and marginal microleakage. Inconsistent data exist regarding whether bovine teeth can be considered an appropriate substitute for human teeth in dental research. Morphological, chemical compostion and physical property differences between the two substrates must be considered when interpreting results obtained from any experiment using bovine tooth substrate.

  7. Factors influencing permanent teeth eruption. Part one--general factors.

    PubMed

    Almonaitiene, Ruta; Balciuniene, Irena; Tutkuviene, Janina

    2010-01-01

    Variation in the normal eruption of teeth is a common finding, but significant deviation from established norms should alert the clinician to take some diagnostic procedures in order to evaluate patient health and development. Disturbance in tooth eruption time could be a symptom of general condition or indication of altered physiology and craniofacial development. The aim of this review is to analyze general factors that could influence permanent teeth eruption. The articles from 1965 to 2009 in English related to topic were identified. 84 articles were selected for data collection. Although permanent teeth eruption is under significant genetic control, various general factors such as gender, socioeconomic status, craniofacial morphology, body composition can influence this process. Most significant disturbance in teeth emergence is caused by systemic diseases and syndromes.

  8. Comparative analysis of human and bovine teeth: radiographic density.

    PubMed

    Tanaka, Jefferson Luis Oshiro; Medici Filho, Edmundo; Salgado, José Antônio Pereira; Salgado, Miguel Angel Castillo; Moraes, Luiz Cesar de; Moraes, Mari Eli Leonelli de; Castilho, Julio Cezar de Melo

    2008-01-01

    Since bovine teeth have been used as substitutes for human teeth in in vitro dental studies, the aim of this study was to compare the radiographic density of bovine teeth with that of human teeth to evaluate their usability for radiographic studies. Thirty bovine and twenty human teeth were cut transversally in 1 millimeter-thick slices. The slices were X-rayed using a digital radiographic system and an intraoral X-ray machine at 65 kVp and 7 mA. The exposure time (0.08 s) and the target-sensor distance (40 cm) were standardized for all the radiographs. The radiographic densities of the enamel, coronal dentin and radicular dentin of each slice were obtained separately using the 'histogram' tool of Adobe Photoshop 7.0 software. The mean radiographic densities of the enamel, coronal dentin and radicular dentin were calculated by the arithmetic mean of the slices of each tooth. One-way ANOVA demonstrated statistically significant differences for the densities of bovine and human enamel (p < 0.05) and for bovine and human coronal dentin (p < 0.05). No statistically significant differences were found for the bovine and human radicular dentin (p > 0.05). Based on the results, the authors concluded that: a) the radiographic density of bovine enamel is significantly higher than that of human enamel; b) the radiodensity of bovine coronal dentin is statistically lower than the radiodensity of human coronal dentin; bovine radicular dentin is also less radiodense than human radicular dentin, although this difference was not statistically significant; c) bovine teeth should be used with care in radiographic in vitro studies.

  9. Congenital oligodontia of the deciduous teeth and anodontia of the permanent teeth in a cat.

    PubMed

    Vieira, Ana Luiza S; Ocarino, Natalia de M; Boeloni, Jankerle N; Serakides, Rogeria

    2009-02-01

    This report describes a rare case of congenital oligodontia of the deciduous teeth and anodontia of the permanent teeth in a cat. According to cat's veterinarian, the patient had only two deciduous upper canines and no permanent teeth had ever erupted. Post-mortem evaluation showed a complete absence of teeth in the oral cavity and inflammatory lesions were not found on the gums. Histopathological analysis of serial sections of maxilla and mandible revealed absence of odontogenic epithelium, inflammatory cells and odontoclastic resorptive lesions. Diagnosis was confirmed after both the establishment that there were no remaining dental structures and the exclusion of other relevant diseases that lead to tooth loss, such as periodontal disease, renal fibrous osteodystrophy, odontoclastic resorptive lesions, ectodermal dysplasia and trauma.

  10. New Approaches in Vital Pulp Therapy in Permanent Teeth

    PubMed Central

    Ghoddusi, Jamileh; Forghani, Maryam; Parisay, Iman

    2014-01-01

    Vitality of dental pulp is essential for long-term tooth survival. The aim of vital pulp therapy is to maintain healthy pulp tissue by eliminating bacteria from the dentin-pulp complex. There are several different treatment options for vital pulp therapy in extensively decayed or traumatized teeth. Pulp capping or pulpotomy procedures rely upon an accurate assessment of the pulp status, and careful management of the remaining pulp tissue. The purpose of this review is to provide an overview of new approaches in vital pulp therapy in permanent teeth. PMID:24396371

  11. Developmental disturbances of permanent teeth following trauma to the primary dentition.

    PubMed

    von Arx, T

    1993-02-01

    The topographic relationship of the apices of the primary teeth to the permanent tooth germs explains the potential for possible developmental disturbances of the permanent teeth after injuries to their predecessors. The anatomical, histologic and clinical aspects of permanent tooth malformation following trauma to the primary teeth are described. One hundred and fourteen children with originally 255 traumatized primary teeth have been re-examined (with an average period of 5.1 years after the trauma) to assess any developmental disturbances of the corresponding permanent teeth. Twenty-three per cent of partially or completely erupted permanent teeth showed developmental disturbances. The most frequent malformation was enamel hypoplasia including enamel discoloration and/or enamel defects. The highest prevalence of developmental disturbances of permanent teeth was found after intrusive injuries of primary teeth.

  12. Brief communication: Emergence chronology of permanent teeth in Nigerian children.

    PubMed

    Oziegbe, Elizabeth O; Esan, Temitope A; Oyedele, Titus A

    2014-03-01

    This study measured the mean age, duration, and sequence of the emergence of permanent dentition in Nigerian children and compared the findings with other population groups. The cross-sectional study involved 1,078 Nigerian children, aged 4-16 years old, from selected primary and secondary schools in the Ife Central local government area in Ile-Ife, Osun State. In general, compared to boys, girls had an earlier mean age of emergence of all the permanent teeth. Children from high socioeconomic class had an earlier mean age of emergence for the maxillary incisors (6.43 and 7.58 years) and mandibular incisors (5.28 and 6.44 years) compared to children from middle and low socioeconomic classes, although socioeconomic effects were more mixed for premolars and molars. Compared to their counterparts in the USA, Australia, Belgium, and Iran, Nigerian children showed an earlier mean age of emergence of all the permanent teeth studied except for Pakistani boys, who had an earlier mean age of emergence of the maxillary premolars and second molar. Poorer economic status has been associated with delayed dental development; however, when compared to other populations, the Nigerian children in this study have earlier mean emergence ages than children from wealthier countries such as the USA and Australia.

  13. Shear Bond Strength and Fracture Analysis of Human vs. Bovine Teeth

    PubMed Central

    Rüttermann, Stefan; Braun, Anika; Janda, Ralf

    2013-01-01

    Purpose To evaluate if bovine enamel and dentin are appropriate substitutes for the respective human hard tooth tissues to test shear bond strength (SBS) and fracture analysis. Materials and Methods 80 sound and caries-free human erupted third molars and 80 freshly extracted bovine permanent central incisors (10 specimens for each group) were used to investigate enamel and dentine adhesion of one 2-step self-etch (SE) and one 3-step etch and rinse (E&R) product. To test SBS the buccal or labial areas were ground plane to obtain appropriate enamel or dentine areas. SE and E&R were applied and SBS was measured prior to and after 500 thermocycles between +5 and +55°C. Fracture analysis was performed for all debonded areas. Results ANOVA revealed significant differences of enamel and dentin SBS prior to and after thermocycling for both of the adhesives. SBS- of E&R-bonded human enamel increased after thermocycling but SE-bonded did not. Bovine enamel SE-bonded showed higher SBS after TC but E&R-bonded had lower SBS. No differences were found for human dentin SE- or E&R-bonded prior to or after thermocycling but bovine dentin SE-bonded increased whereas bovine dentine E&R-bonded decreased. Considering the totalized and adhesive failures, fracture analysis did not show significances between the adhesives or the respective tooth tissues prior to or after thermocycling. Conclusion Although SBS was different on human and bovine teeth, no differences were found for fracture analysis. This indicates that solely conducted SBS on bovine substrate are not sufficient to judge the perfomance of adhesives, thus bovine teeth are questionnable as a substrate for shear bond testing. PMID:23527125

  14. [Spontaneous loss of permanent teeth in children is never innocent].

    PubMed

    Wit, M A; van der Meij, E H; Hooimeijer, L H; de Vries, T W

    2013-06-01

    A 13-year-old patient spontaneously lost tooth 47. In addition, he had for several weeks experienced numbness of the lower lip and the chin on the right side, fatigue, weakness, loss of appetite, and weight loss. After extensive investigation he seemed to be suffering from a Burkitt lymphoma. Spontaneous loss of permanent teeth in children has an extensive differential diagnosis. Dentists should be familiar with this differential diagnosis as all possible diagnoses are related to serious pathologies. The differential diagnosis includes infectious, metabolic, naplastic, and odontogenic causes. Systematic history taking, physical examination and laboratory investigations will lead to a proper diagnosis.

  15. Clinical complications in the revascularization of immature necrotic permanent teeth.

    PubMed

    Dabbagh, Basma; Alvaro, Emanuel; Vu, Duy-Dat; Rizkallah, Jean; Schwartz, Stephane

    2012-01-01

    The purpose of this case series was to report on the use of a technique of revascularization for necrotic immature permanent teeth, several problems encountered, and solutions to those problems. Eighteen pulp revascularizations were performed in 2009 using the original protocol of revascularization (adapted from the AAE/AAPD joint meeting in 2007 in Chicago). The protocol consisted of opening the canal and disinfecting it with sodium hypochlorite, sealing in a triple antibiotic paste for 2-6 weeks, re-opening, re-irrigating, creating a blood clot in the canal, and sealing with an MTA barrier over the clot. Three problems were encountered during the treatment: (1) bluish discoloration of the crown; (2) failure to produce bleeding; and (3) collapse of the mineral trioxide aggregate (MTA) material into the canal. Modifications to solve these problems included: changing one of the antibiotics, using a local anesthesia without epinephrine, and adding collagen matrix to the blood clot.

  16. Boon of MTA Apexification in Young Permanent Posterior Teeth

    PubMed Central

    Kumar, Vinod; Prasad, Vijaya; Mahantesh, T.

    2014-01-01

    Single visit apexification using mineral trioxide aggregate (MTA) is a new boon in effective management of nonvital tooth with an open apex which has steadily gained popularity with clinicians; also it shortens the treatment period and improves patient compliance. Importance of this approach lies in expedient cleaning and shaping of the root canal system, followed by its apical seal with MTA. There are several case reports available describing the use of MTA as an apexification agent in incisors and premolar, but presented cases are the unique case reports demonstrating successful apexification procedure using MTA in young permanent mandibular molars. After eight-month follow-up, teeth were without any abnormal clinical symptoms; rather there were radiographic resolution of the periapical lesion and induction of root end closure with new hard tissue formation over MTA. PMID:25431690

  17. On the linearization of eruption series of the permanent teeth.

    PubMed

    Kanno, R

    1997-11-01

    In order to confirm the linearization of permanent eruption, Masuyama's linearization method was applied to the data of Kitamura's study. At first, we considered the eruption age t alpha i of permanent teeth T alpha, where alpha corresponds a tooth of every description, and examined the linear regression of Y alpha i = log10 t alpha i on m(y) alpha (the mean of Y alpha i with respect to i), but the result was not good. For the correlation coefficient r between two variables in linear regression, the percentage of subjects with r > or = 0.970 was only 10.3% in males and 28.8% in females in Kitamura's study. Next we took notice of the eruption age u beta i of each tooth, which is the beta-th in order of eruption. The fitness of the linear regression of Z beta i = log10 u beta i on mz beta (the mean of Z beta i) was very good. The percentage of subjects with r > or = 0.970 increased to 80.0% in males and 86.0% in females. Then we used m(y) (beta) (rearranged m(y) alpha in order of increasing size) instead of mz beta as an independent variable in the linear regression. The degree of the linearization was slightly inferior to that using mz beta. In every linearization, a quasi-fixed point with coordinates (C, C) existed on the linearized dentition plot, where the value of C was almost equal in each way, i.e., C = 10.23 (years) for males and C = 8.91 (years) for females in Kitamura's data. This linearized dentition plot will be useful in detecting certain growth disturbances. The existence of a quasi-fixed point may be useful in forecasting the age of the eruption of subsequent teeth, once the first eruption is observed.

  18. Mesiodistal crown diameters of the primary and permanent teeth in southern Chinese--a longitudinal study.

    PubMed

    Yuen, K K; So, L L; Tang, E L

    1997-12-01

    The mesiodistal crown diameters of the primary and permanent teeth were measured on serial casts of 112 Hong Kong Southern Chinese (61 males and 51 females) taken at 5.68 and 12.31 years of age. None of the teeth showed significant sex difference in bilateral asymmetry, and significant bilateral asymmetry was found only for the upper primary second molars. The asymmetries were small and the sizes of the antimeres were averaged. Posterior teeth were generally less variable than anterior teeth in both dentitions in Chinese, which is contrary to other reports, but the anterior tooth of each morphological class was, in general, less variable than the posterior member. Male teeth were larger than those of females except for the lower central and lateral incisors in both dentitions, but the difference was not statistically significant. None of the primary teeth nor three of the permanent teeth were found to have significant sex differences in size. Percentage sexual dimorphism ranged from 0.06 to 1.97 per cent for the primary teeth and from 0.36 to 5.27 per cent for the permanent teeth. In the primary dentition, molars were the most dimorphic teeth in both arches, while upper incisors and lower canine were the least dimorphic teeth in their own arch. Among the permanent teeth, the canines were the most dimorphic and the incisors were among the least dimorphic teeth in both arches. Tooth sizes in both dentitions were, in general, larger than those of the Caucasians, comparable with Northern Chinese, but smaller than those of Australian Aboriginals.

  19. Supragingival Microbial Profiles of Permanent and Deciduous Teeth in Children with Mixed Dentition

    PubMed Central

    Shi, Weihua; Qin, Man; Chen, Feng; Xia, Bin

    2016-01-01

    Objectives The present study was designed to investigate the microbial profiles of teeth in different locations in mixed-dentition-stage children, and to compare the microbiomes of permanent and deciduous teeth in the same healthy oral cavity. Methods Supragingival plaque samples of teeth in various locations—the first permanent molars, deciduous molars, deciduous canines and incisors and permanent incisors—were collected from 20 healthy mixed-dentition-stage children with 10–12 permanent teeth erupted. Plaque DNA was extracted, and the V3–V4 hypervariable region of the bacterial 16S rRNA gene was amplified and subjected to sequencing. Results On average, 18,051 high-quality sequences per sample were generated. Permanent tooth sites tended to host more diverse bacterial communities than those of deciduous tooth sites. A total of 12 phyla, 21 classes, 38 orders, 66 families, 74 genera were detected ultimately. Five predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria and Actinobacteria) were highly variable among sites. Of 26 genera with a mean relative abundance of >0.1%, 16 showed significant differences in relative abundance among the groups. More than 20% of the total operational taxonomical units were detected only in permanent or deciduous teeth. The variation in the microbial community composition was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema. The core microbiome of supragingival plaque in mixed dentition comprised 19 genera with complex correlationships. Conclusion Our results suggest differences in microbial diversity and composition between permanent and deciduous teeth sites in mixed dentition. Moreover, the core microbiome of these sites was determined. These findings enhance our understanding of the development of the native oral microbiota with age. PMID:26752284

  20. Dental Age and Tooth Development in Orthodontic Patients with Agenesis of Permanent Teeth

    PubMed Central

    Badrov, Jozo; Lauc, Tomislav; Nakaš, Enita

    2017-01-01

    Objective. To compare the development of permanent teeth in a group of children with the congenitally missing permanent teeth (CMPT) and corresponding nonaffected group. Methods. The formation stages of all developing permanent teeth were determined on 345 panoramic radiographs (OPTs) by the method of Haavikko (1970), and dental age was calculated. The paired samples t-test was used to compare the differences between dental age (DA) and chronological age (CA) in those with CMPT and those not affected. Spearman test was used to evaluate the correlation between DA-CA and the number of missing teeth. The Wilcoxon signed rank test was used to compare the development of the teeth adjacent to the place of the agenesis with matched pair in corresponding nonaffected group. Results. Dental age was significantly delayed in CMPT children compared to the nonaffected group (p < 0.001). The mean differences were −0.57 ± 1.20 years and −0.61 ± 1.23 years in males and females, without difference between sexes (p = 0.763). The number of missing teeth affected the delay only in females (p = 0.024). Only mesial teeth in females were significantly delayed in development when compared to the nonaffected group (p = 0.007). Conclusion. Our findings show that the development of the permanent teeth is delayed when compared to the nonaffected group of the same sex and age. PMID:28331854

  1. Correlation between the strength of glass ionomer cements and their bond strength to bovine teeth.

    PubMed

    Hibino, Yasushi; Kuramochi, Ken-ichi; Harashima, Atsushi; Honda, Muneaki; Yamazaki, Atsushi; Nagasawa, Yuko; Yamaga, Taniichiro; Nakajima, Hiroshi

    2004-12-01

    This study examined the possible correlation between the strength of glass ionomers and their adhesive strength to bovine teeth. The shear bond strengths of three different brands of glass ionomer mixed at four different P/L ratios to bovine teeth were measured 24 hours after the cement specimens were prepared. The correlation between shear bond strength and mechanical strength reported in our previous study was also examined. No significant (p > 0.05) increases in the bond strength to bovine teeth were found in any of the cements when the mixing ratio increased. The present study showed no significant (p > 0.05) correlation between mechanical strength of cement and its bond strength to bovine teeth. Rather than trying to increase the strength of the cement, it would be more effective to enhance the adhesive bond strength through procedures such as surface conditioning or cleaning of the tooth structure when glass ionomers are used as luting agents.

  2. Educational material of dental anatomy applied to study the morphology of permanent teeth.

    PubMed

    Siéssere, Selma; Vitti, Mathias; de Sousa, Luiz Gustavo; Semprini, Marisa; Regalo, Simone Cecílio Hallak

    2004-01-01

    The purpose of this report is to present educational material that would allow the dental student to learn to easily identify the morphologic characteristics of permanent teeth, and how they fit together (occlusion). In order to do this, macro models of permanent teeth with no attrition were carved in wax and later molded with alginate. These molds were filled with plaster, dental stone and/or cold-cured acrylic resin. The large individual dental stone tooth models were mounted on a wax base, thus obtaining maxillary and mandibular arches which were occluded. These dental arches were molded with plaster or dental stone. The authors suggest that these types of macro models allow an excellent visualization of the morphologic characteristics of permanent teeth and occlusion. Dental students are able to carve the permanent dentition in wax with great facility when they can observe macro models.

  3. Vascular endothelial growth factor receptor-2 expression in the pulp of human primary and young permanent teeth.

    PubMed

    Grando Mattuella, Leticia; Poli de Figueiredo, José Antonio; Nör, Jacques E; de Araujo, Fernando Borba; Medeiros Fossati, Anna Christina

    2007-12-01

    The purpose of this study was to evaluate the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) in endothelial cells within the dental pulp of human primary and young permanent teeth and the spatial distribution of VEGFR-2-positive cells. Nine sound primary teeth and 4 sound young permanent teeth were evaluated by immunohistochemistry with a human anti-VEGFR-2 antibody. Stained tissue sections were analyzed qualitatively under light microscopy. Here we observed that endothelial cells of both primary and permanent teeth showed positive immunostaining for VEGFR-2. Notably, VEGFR-2-positive cells in the primary teeth tended to be found close to the subodontoblastic layer, whereas the spatial distribution of VEGFR-2 immunostaining in the permanent teeth was more uniform. In conclusion, VEGFR-2 was expressed in the microvascular endothelial cells of both primary and young permanent teeth, which suggests that these cells are capable of responding to the morphogenetic and survival signals mediated by VEGF.

  4. Mesiodistal root angulation of permanent teeth in children with mixed dentition and normal occlusion

    PubMed Central

    JESUINO, Flávia A. S.; COSTA, Luciane R.; VALLADARES-NETO, José

    2010-01-01

    Objective There is little information regarding the mesiodistal angulation of permanent teeth in mixed dentition. The aim of this study was to evaluate mesiodistal root angulation of permanent incisors, canines and first molars of 100 Brazilian children, using a new horizontal reference plane based on the midpoint of the intercuspation of primary canines and permanent first molars in panoramic radiographs during the mixed-dentition phase. Material and methods Children were equally divided between the genders with a mean age of 8.9 years (SD=0.76), normal occlusion and no eruptive disturbances. Results The angulation of the permanent maxillary first molars was close to the vertical, whereas the mandibular molars presented approximately 25 degrees of distal root angulation. The maxillary canines were the most distally angulated teeth, whereas the permanent mandibular canines were vertically positioned. The evaluation of the anterior maxillary area showed vertical position of permanent lateral, and central incisors with a slight distal angulation, whereas the permanent mandibular incisors tended to a mesial radicular convergence. Conclusions The proposed reference line could be useful in mixed dentition root angulation evaluation; there was a slight asymmetry in the mesiodistal angulation among homologous teeth, and also a small variation between the male and the female groups, but no difference between 8-and 10-year-old children. PMID:21308295

  5. Agenesis of Multiple Primary and Permanent Teeth Unilaterally and its Possible Management

    PubMed Central

    Ephraim, Rena; Rajamani, T; Feroz, TP Mohammed; Abraham, Sajith

    2015-01-01

    Oligodontia is the agenesis of numerous teeth (more than six teeth). Agenesis of teeth in primary and permanent dentition is a rare incidence and very few are reported in the dental literature. Although the etiology of congenital agenesis of teeth is unclear, several factors such as a tendency toward genetic predilection, metabolic disorders, trauma, infection, radiation or idiopathic reasons are found to be responsible. Available literature reports agenesis most often of third molars, maxillary lateral incisors, mandibular central and lateral incisors, and mandibular second premolars in decreasing order of frequency of occurrence. Males are more often affected than females. Maxillary primary teeth are more often found affected by agenesis than mandibular primary teeth. Available literature reports missing teeth to be found unilaterally or orbilaterally with a predisposition toward a similar phenomenon occurring in the permanent dentition. In congenital agenesis impaired growth of the alveolar process, reduced lower facial height, speech impairment, deep bite, restriction in the movement of the tongue due to ankyloglossia, asymmetry of the affected side of the face are clinical features evident. There has been no report of complete agenesis of primary and permanent teeth in a whole mandibular quadrant in conjunction with the absence of maxillary second and third molars on the affected side. Here, we report an incidence of a rare occurrence of complete agenesis of more than 10 primary and permanent teeth, unilaterally, in the right mandibular quadrant, in a child of 10 years presenting with a chief complaint of several missing primary teeth and difficulty in speech due to its complete absence. Treatment strategies included various orthodontic and restorative procedures to improve esthetics and function. The orthodontic procedures involved expansion of the narrow maxillary arch to obtain a functionally adapted occlusion and creation of space for future alignment, and

  6. Agenesis of multiple primary and permanent teeth unilaterally and its possible management.

    PubMed

    Ephraim, Rena; Rajamani, T; Feroz, Tp Mohammed; Abraham, Sajith

    2015-05-01

    Oligodontia is the agenesis of numerous teeth (more than six teeth). Agenesis of teeth in primary and permanent dentition is a rare incidence and very few are reported in the dental literature. Although the etiology of congenital agenesis of teeth is unclear, several factors such as a tendency toward genetic predilection, metabolic disorders, trauma, infection, radiation or idiopathic reasons are found to be responsible. Available literature reports agenesis most often of third molars, maxillary lateral incisors, mandibular central and lateral incisors, and mandibular second premolars in decreasing order of frequency of occurrence. Males are more often affected than females. Maxillary primary teeth are more often found affected by agenesis than mandibular primary teeth. Available literature reports missing teeth to be found unilaterally or orbilaterally with a predisposition toward a similar phenomenon occurring in the permanent dentition. In congenital agenesis impaired growth of the alveolar process, reduced lower facial height, speech impairment, deep bite, restriction in the movement of the tongue due to ankyloglossia, asymmetry of the affected side of the face are clinical features evident. There has been no report of complete agenesis of primary and permanent teeth in a whole mandibular quadrant in conjunction with the absence of maxillary second and third molars on the affected side. Here, we report an incidence of a rare occurrence of complete agenesis of more than 10 primary and permanent teeth, unilaterally, in the right mandibular quadrant, in a child of 10 years presenting with a chief complaint of several missing primary teeth and difficulty in speech due to its complete absence. Treatment strategies included various orthodontic and restorative procedures to improve esthetics and function. The orthodontic procedures involved expansion of the narrow maxillary arch to obtain a functionally adapted occlusion and creation of space for future alignment, and

  7. [Molar incisor hypomineralisation in the first permanent teeth].

    PubMed

    Ivanović, Mirjana; Zivojinović, Vesna; Sindolić, Mirjana; Marković, Dejan

    2007-01-01

    The aim of this study was to point out the prevalence of hypomineralised molars and incisors and emphasize importance of this condition in paediatric dentistry. This condition is defined as hypomineralisation of one or more first permanent molars frequently affecting incisors and referred to as molar incisor hypomineralisation (MIH). Aetiology of MIH has not been fully clarified and numerous aetiological factors have been cited. Hypomineralised molars are more prone to caries, cause severe restorative problems and are frequently extracted due to serious damage and caries complications. Incisors can present demarcated enamel opacities, while enamel breakdown is uncommon. Considering the fact that permanent first molars with severe defects demand complex treatment, they represent a serious problem for the patient as well as for the dentist.

  8. The potential of deciduous and permanent bovine enamel as substitute for deciduous and permanent human enamel: Erosion-abrasion experiments.

    PubMed

    Attin, Thomas; Wegehaupt, Florian; Gries, David; Wiegand, Annette

    2007-10-01

    Aim of the present study was to compare toothbrushing abrasion of eroded human and bovine enamel utilizing a toothpaste slurry. The surfaces of each 36 teeth from cattle and calves and from each 36 human wisdom teeth and deciduous teeth were polished. Each 12 specimens from the respective tooth type were used for assessing toothbrushing abrasion only (A), erosion only (E) and the combination of erosion and toothbrushing abrasion (EA). The EA samples were subjected to 20 cycles comprising a demineralization/remineralization procedure directly followed by toothbrushing abrasion (100 strokes, 300 g load, toothpaste slurry: 3 ml artificial saliva mixed with 1g dentifrice). Demineralization in form of erosion was performed with 1% citric acid (1 min), remineralization with artificial saliva (15 min). Between the cycles, the samples were stored in artificial saliva. Wear of the treated surfaces with reference to untreated areas was determined profilometrically. The samples subjected to abrasion only (A) did not show a significantly different wear between the different kinds of teeth. The comparisons of substance loss between teeth of different species revealed that hard tissue loss of the human deciduous teeth was significantly lower as compared to calves' teeth after both erosion and erosion-abrasion. Also, both erosion only and erosion-abrasion caused higher enamel loss in cattle's teeth than in human wisdom teeth. It is concluded that human eroded enamel offers better resistance against brushing than bovine enamel.

  9. Pulpotomy of Symptomatic Permanent Teeth with Carious Exposure Using Mineral Trioxide Aggregate

    PubMed Central

    Barngkgei, Imad Hassan; Halboub, Esam Saleh; Alboni, Roula Safouh

    2013-01-01

    Introduction To evaluate the clinical and radiographic outcomes of pulpotomy treatment with mineral trioxide aggregate (MTA) in symptomatic mature permanent teeth with carious exposure. Materials and Methods Ten patients aged 27-54 years presented with 11 symptomatic permanent teeth (n=11). Each offending carious tooth was clinically and radiographically determined. We removed caries as conservatively as possible; however pulp exposure was inevitable. ProRoot MTA pulpotomy was performed on these teeth. The patients were followed-up clinically and radiographically for 24-42 months. Results Immediate relief of patients` symptoms occurred. Moreover, teeth responses to the electric pulp tester were within normal range on follow-up appointment and the radiographs did not reveal any abnormality/lesion in the periapical areas. Conclusion Pulpotomy using MTA could be a good alternative for root canal therapy (RCT) for managing symptomatic mature permanent teeth with carious exposure, however further large-scale multicenter clinical trials are highly encouraged to confirm this hypothesis. PMID:23717332

  10. Torque ripple minimization in a doubly salient permanent magnet motors by skewing the rotor teeth

    NASA Astrophysics Data System (ADS)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-09-01

    This paper presents the effects of skewing the rotor teeth on the performance of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the 2-D FE analysis. The optimum skewing angle is obtained as 12-15° for the least ripple torque without much reduction in the back-emf.

  11. Treatments for intrusive luxation in permanent teeth: a systematic review and meta-analysis.

    PubMed

    Costa, L A; Ribeiro, C C C; Cantanhede, L M; Santiago Júnior, J F; de Mendonça, M R; Pereira, A L P

    2017-02-01

    Intrusive luxation is a severe form of dental trauma and there is no consensus regarding its management for permanent teeth. A systematic review and meta-analysis was performed to identify the appropriate treatment for teeth with intrusive luxation. The PubMed/MEDLINE, Embase, US Clinical Trials, and ISRCTN Registry electronic databases were used to search for articles in English and unpublished studies without a date limit. Eligible studies evaluated periodontal results (root resorption as the primary outcome; marginal bone defects and/or pulpal changes as secondary outcomes) after spontaneous re-eruption (SRE), orthodontic repositioning (ORP), or surgical repositioning (SRP) for patients with one or more traumatically intruded permanent teeth. Risk ratios with 95% confidence intervals were used to compare treatments. The meta-analysis revealed no significant difference (P>0.05) between SRP and SRE for root resorption. For secondary outcomes, SRE was significantly better than SRP and ORP (P<0.05). Subgroup analyses showed no significant differences among treatments in teeth with completely formed roots (P>0.05) and a better prognosis when SRE was performed in teeth with incompletely formed roots (P<0.05). The available evidence does not allow us to conclude on the best treatment for traumatically intruded teeth. More reliable evidence is needed.

  12. Root lengths in 47,XYY males' permanent teeth.

    PubMed

    Lähdesmäki, R; Alvesalo, L

    2004-10-01

    Studies on individuals with sex chromosome anomalies have demonstrated the promoting effect of the Y chromosome on tooth crown enamel and dentin growth. The present research investigated permanent tooth root lengths in 47,XYY males. The measurements were made from panoramic radiographs. The results indicate longer tooth roots in 47,XYY males compared with those in control males and females. The promoting effect of the Y chromosome on dental growth thus continues in the form of root dentin after the completion of crown growth. The results, together with those on tooth crown sizes in 47,XYY males, suggest that growth excesses are evident and final, beginning a few months after birth and continuing up to the age of 14 years, at least. The excess root dentin growth in 47,XYY males, as well as sexual dimorphism in the growth of crown and root dentin, might be caused by the same factor on the Y chromosome.

  13. Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth

    PubMed Central

    Bhagavatula, Pradeep; Levy, Steven M; Broffitt, Barbara; Weber-Gasparoni, Karin; Warren, John J

    2015-01-01

    Objective Very few studies have examined the relationship between timing of fluoride intake and development of dental fluorosis on late-erupting permanent teeth using period-specific fluoride intake information. This study examined this relationship using longitudinal fluoride intake information from the Iowa Fluoride Study. Methods Participants’ fluoride exposure and intake (birth to 10 years) from water, beverages, selected food products, dietary fluoride supplements and fluoride toothpaste was collected using questionnaires sent to parents at 3- and 4- month intervals from birth to age 48 months, and every six months thereafter. Three trained and calibrated examiners used the Fluorosis Risk Index (FRI) categories to assess 16 late-erupting teeth among 465 study participants. A tooth was defined as having definitive fluorosis if any of the zones on that tooth had an FRI score of 2 or 3. Participants with questionable fluorosis were excluded from analyses. Descriptive and logistic regression analyses were performed to assess the importance of fluoride intake during different time periods. Results Most dental fluorosis in the study population was mild, with only 4 subjects (1%) having severe fluorosis (FRI Score 3). The overall prevalence of dental fluorosis was 27.8%. Logistic regression analyses showed that fluoride intake from each of the individual years from age 2 to 8 years plays an important role in determining the risk of dental fluorosis for most late-erupting permanent teeth. The strongest association for fluorosis on the late-erupting permanent teeth was with fluoride intake during the sixth year of life. Conclusion Late-erupting teeth may be susceptible to fluorosis for an extended period from about age 2 to 8 years. Although not as visually prominent as the maxillary central incisors, some of the late-erupting teeth are esthetically important and this should be taken into consideration when making recommendations about dosing of fluoride intake. PMID

  14. Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials

    PubMed Central

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Galafassi, Daniel; Borsatto, Maria Cristina

    2015-01-01

    Objectives: The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials. Materials and Methods: Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield®), a glass ionomer based fissure sealant (Vitremer®), and two microhybrid composite resins (Filtek Z250 and P90®). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P < 0.05). Results: No difference in hardness was encountered between deciduous and permanent teeth (P < 0.05) or modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested. Conclusions: Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load. PMID:26929700

  15. Time of mineralization of permanent teeth in children and adolescents in Gaborone, Botswana.

    PubMed

    Cavrić, Jelena; Vodanović, Marin; Marušić, Ana; Galić, Ivan

    2016-01-01

    The mineralization sequence of permanent dentition can be used to assess the stage of development and age of individuals. The most commonly used methods are based on the assessment of developmental stages of target groups of teeth on one side of the lower jaw. When compared with the rest of the world, fewer studies have been done on dental age in Sub-Saharan Africa, particularly in the region of Southern Africa. The aim of this study was to determine the chronology of mineralization of permanent teeth by the evaluation of developmental stages according to the Demirjian's method from 1973 and to evaluate dental age by using sex-specific self-weighted scores for dental stages and 50th percentile conversion tables of total maturity scores of seven mandibular teeth. We used a sample of panoramic radiographs (OPTs) of black African children and adolescents from the city of Gaborone, Botswana, with the aim of forming an appropriate sample to evaluate the development of the teeth in this socio-geographic environment. The final sample consisted of 1760 OPTs (807 males and 953 females) of individuals aged 6-23 years. The developmental stages of the all permanent teeth in the left side of the maxilla and the mandible were evaluated. Comparing the maxilla and the mandible, we found similar development within different stages for most of the teeth. In comparison to the average age at each stage of development, including the third molars between males and females, it is evident that females are slightly faster in developing permanent teeth, but without statistical significance for most of the developmental stages. Applying 50th percentile conversion tables for calculating the dental age for the first seven mandibular teeth, 616 OPTs of the children (299 males and 317 females), aged 6.08-16.80 years, were evaluated and their dental age was calculated. Mean dental age was overestimated in comparison to chronological age by 1.25±1.11 years and 0.72±1.02 years for males and

  16. Development of the permanent mandibular cheek teeth in fallow deer (Dama dama).

    PubMed

    Kierdorf, H; Hommelsheim, S; Kierdorf, U

    2012-12-01

    The study describes crown and root formation of the permanent mandibular cheek teeth of fallow deer from a gestational age of 22-23 weeks up to a post-natal age of 33 months. Tooth development was recorded using a scoring scheme based on morphological criteria ranging from crypt formation to completion of root growth. The morphological appearance of the enamel surface during three different stages (secretory-stage enamel, maturation-stage enamel and mature enamel) was described, and the approximate age at termination of the secretory stage of amelogenesis in the deciduous and permanent mandibular cheek teeth was determined. The data enable an age estimation of fallow deer up to 3 years of age and provide a basis for assessing the timing of stress episodes that affect tooth crown formation. This information is useful for the management of the species as well as in bioarchaeological and bioindication studies.

  17. Effect of skewing the rotor teeth on the performance of doubly salient permanent magnet motors

    NASA Astrophysics Data System (ADS)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-04-01

    This paper presents the effects of skewing the rotor teeth on the performance characteristics such as flux linkage, back emf, phase inductance, and reluctance torque of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the two-dimensional finite element analysis. The optimum skewing angle is obtained as 12°-15° for the least ripple torque without much reduction in the back emf. Skewing the rotor teeth of an 8/6 doubly salient permanent magnet motor by 12°-15° will reduce the total harmonic distortion of the back emf profile to 29.69% from the original value of 44.69%. The reduction in the amplitude of the back emf in this case will be 18.79% only.

  18. Coronal microleakage of permanent lingual access restorations in endodontically treated anterior teeth.

    PubMed

    Wilcox, L R; Diaz-Arnold, A

    1989-12-01

    Forty-six intact extracted human anterior teeth were treated endodontically with laterally condensed gutta-percha and sealer. The teeth were restored with a base of either zinc phosphate or temporary stopping and a permanent restoration of either acid etched composite resin with GLUMA as the dentin bonding agent or with Ketac-Fil glass ionomer. The teeth were thermocycled, coated with nail varnish (except for the access), immersed in silver nitrate, developed, and sectioned longitudinally. The linear dye penetration was measured. All restorations permitted leakage into the base. All groups had specimens which leaked into the gutta-percha. There was a tendency for the glass ionomer/zinc phosphate group to leak least, but there were no statistically significant differences among the groups.

  19. Contribution of prosthetic treatment considerations for dental extractions of permanent teeth.

    PubMed

    Fernández-Barrera, Miguel Ángel; Medina-Solís, Carlo Eduardo; Casanova-Rosado, Juan Fernando; Mendoza-Rodríguez, Martha; Escoffié-Ramírez, Mauricio; Casanova-Rosado, Alejandro José; Navarrete-Hernández, José de Jesús; Maupomé, Gerardo

    2016-01-01

    Background. Tooth loss is an easily identifiable outcome that summarizes a complex suite of factors in an individual's history of dental disease and its treatment by dental services over a lifetime. Assessment of overall tooth loss data is essential for epidemiologically evaluating the adequacy of dental care provided at a systems level, as well as for placing in context tooth loss for non-disease causes. For example, when derived from prosthetic treatment planning, the latter may unfortunately lead to some teeth being extracted (pulled) for the sake of better comprehensive clinical results. The objective of the present manuscript was to identify the contribution to overall tooth loss, by extraction of permanent teeth because of prosthetic treatment reasons. Material and Methods. A cross-sectional study included sex, age, total number of extractions performed by subject, sextant (anterior vs. posterior), group of teeth (incisors, canines, premolars and molars), upper or lower arch, and the main reason underlying extraction (extraction for any reason vs. prosthetic treatment), in patients 18 years of age and older seeking care at a dental school clinic in Mexico. A multivariate logistic regression model was generated. Results. A total of 749 teeth were extracted in 331 patients; 161 teeth (21.5% of total) were extracted for explicit prosthetic treatment indications. As age increased, the likelihood of having an extraction for prosthetic reasons increased 3% (OR = 1.03, p < 0.001). Women (OR = 1.57, p < 0.05) were more likely to be in this situation, and molars (OR = 2.70, p < 0.001) were most at risk. As the total number of extractions increased, the risk of having an extraction for prosthetic reasons decreased (OR = 0.94, p < 0.05). Conclusions. A significant amount (21.5%) of the extractions of permanent teeth were performed for prosthetic reasons in this dental school clinical environment; age, sex, type of tooth, and the total number of extractions moderated

  20. Contribution of prosthetic treatment considerations for dental extractions of permanent teeth

    PubMed Central

    Fernández-Barrera, Miguel Ángel; Casanova-Rosado, Juan Fernando; Mendoza-Rodríguez, Martha; Escoffié-Ramírez, Mauricio; Casanova-Rosado, Alejandro José; Navarrete-Hernández, José de Jesús; Maupomé, Gerardo

    2016-01-01

    Background. Tooth loss is an easily identifiable outcome that summarizes a complex suite of factors in an individual’s history of dental disease and its treatment by dental services over a lifetime. Assessment of overall tooth loss data is essential for epidemiologically evaluating the adequacy of dental care provided at a systems level, as well as for placing in context tooth loss for non-disease causes. For example, when derived from prosthetic treatment planning, the latter may unfortunately lead to some teeth being extracted (pulled) for the sake of better comprehensive clinical results. The objective of the present manuscript was to identify the contribution to overall tooth loss, by extraction of permanent teeth because of prosthetic treatment reasons. Material and Methods. A cross-sectional study included sex, age, total number of extractions performed by subject, sextant (anterior vs. posterior), group of teeth (incisors, canines, premolars and molars), upper or lower arch, and the main reason underlying extraction (extraction for any reason vs. prosthetic treatment), in patients 18 years of age and older seeking care at a dental school clinic in Mexico. A multivariate logistic regression model was generated. Results. A total of 749 teeth were extracted in 331 patients; 161 teeth (21.5% of total) were extracted for explicit prosthetic treatment indications. As age increased, the likelihood of having an extraction for prosthetic reasons increased 3% (OR = 1.03, p < 0.001). Women (OR = 1.57, p < 0.05) were more likely to be in this situation, and molars (OR = 2.70, p < 0.001) were most at risk. As the total number of extractions increased, the risk of having an extraction for prosthetic reasons decreased (OR = 0.94, p < 0.05). Conclusions. A significant amount (21.5%) of the extractions of permanent teeth were performed for prosthetic reasons in this dental school clinical environment; age, sex, type of tooth, and the total number of extractions moderated

  1. Miniature Pulpotomy of Symptomatic Mature Permanent Teeth: A Report of Two Cases

    PubMed Central

    Asgary, Saeed; Nourzadeh, Mahdieh; Eghbal, Mohammad Jafar

    2016-01-01

    Human dental pulp inflammation can progress to periapical lesion formation and conventional root canal treatment (RCT) has been the traditional method for disease management. This observational study presents two cases of vital pulp therapy in mature molars diagnosed with irreversible pulpitis and associated with apical periodontitis. In these two clinical cases, the involved teeth had deep carious lesions with a history of spontaneous/lingering pain and radiographic examinations revealed the presence of apical radiolucencies. A conservative miniature pulpotomy (MP) using calcium-enriched mixture (CEM) was performed and the teeth were permanently restored with amalgam. Clinical evaluations indicated resolution of pain 24 hours after treatment; the teeth showed normal vitality, remained asymptomatic and maintained normal function after recall examinations. Furthermore, the 18-month radiographic evaluation showed healing of the apical lesions. Vital pulp therapy using the MP technique with CEM appeared successful in avoiding RCT intervention. These two reports of case outcome suggest that simple MP using a CEM bioregenerative technique may provide a favorable outcome for permanent teeth diagnosed with irreversible pulpitis and associated with apical periodontitis. PMID:26843883

  2. MARGINAL ADAPTATION AND PERFORMANCE OF BIOACTIVE DENTAL RESTORATIVE MATERIALS IN DECIDUOUS AND YOUNG PERMANENT TEETH

    PubMed Central

    Gjorgievska, Elizabeta; Nicholson, John W.; Iljovska, Snezana; Slipper, Ian J.

    2008-01-01

    Objective: The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glass-ionomers, though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resin-based materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits. PMID:19089281

  3. Root maturation and dentin–pulp response to enamel matrix derivative in pulpotomized permanent teeth

    PubMed Central

    Darwish, Sherif S; Abd El Meguid, Shadia H; Wahba, Nadia A; Mohamed, Ahmed A-R; Chrzanowski, Wojciech

    2014-01-01

    The success of pulpotomy of young permanent teeth depends on the proper selection of dressing materials. This study aimed to evaluate the histological and histomorphometric response of dentin–pulp complex to the enamel matrix derivative (Emdogain® gel) compared to that of calcium hydroxide when used as a pulp dressing in immature young permanent dogs’ teeth. Dentin-like tissues bridging the full width of the coronal pulp at the interface between the injured and healthy pulp tissues were seen after 1 month in both groups. With time, the dentin bridge increased in thickness for calcium hydroxide but disintegrated and fully disappeared for Emdogain-treated group. Progressive inflammation and total pulp degeneration were only evident with Emdogain-treated group. The root apices of Emdogain-treated teeth became matured and closed by cementum that attached to new alveolar bone by a well-oriented periodontal ligament. In young permanent dentition, Emdogain could be a good candidate for periodontium but not dentino–pulpal complex regeneration. PMID:24551447

  4. 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

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

    SciTech Connect

    Lan, Shoujen; Yen, Yeayin; Ko, Yingchin; Chen, Engrin )

    1989-06-01

    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 eleven 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.

  6. Orthodontic Management with Traction and Asymmetric Extraction for Multiple Impacted Permanent Maxillary Teeth – A Case Report

    PubMed Central

    Niu, Qiannan; Zhang, Liang; Dai, Juan; Li, Feifei; Feng, Xue

    2016-01-01

    Multiple impacted teeth are a rare eruption disturbance that increases the case complexity. In this article, we described a 13-year-old boy whose 5 permanent maxillary teeth were not erupted although their root formation was complete. The orthodontic treatment with traction and asymmetric extraction was performed to achieve a significantly improved functional and esthetic result. PMID:27857816

  7. Outcomes of Different Vital Pulp Therapy Techniques on Symptomatic Permanent Teeth: A Case Series

    PubMed Central

    Asgary, Saeed; Fazlyab, Mahta; Sabbagh, Sedigheh; Eghbal, Mohammad Jafar

    2014-01-01

    In modern endodontics, vital pulp therapy (VPT) has been considered an ultra-conservative treatment modality. Based on the level of pulp preservation, VPT includes stepwise excavation, indirect pulp capping (IDPC), direct pulp capping (DPC), miniature pulpotomy (MP), partial/Cvek pulpotomy and coronal/complete pulpotomy (CP). The present article reviews the treatment outcomes of 94 permanent teeth with irreversible pulpitis treated with either IDPC (n=28), DPC (n=28), MP (n=29) or CP (n=9) using calcium-enriched mixture (CEM) cement. After a mean follow-up time of 12.3 months, 93 treated teeth were radiographic/clinically successful; only one radiographic failure was observed in the DPC group. PMID:25386213

  8. Effect of needle insertion depth and apical diameter on irrigant extrusion in simulated immature permanent teeth.

    PubMed

    Aksel, Hacer; Askerbeyli, Sevinc; Canbazoglu, Cigdem; Serper, Ahmet

    2014-01-01

    The aim of this study was to compare the amount of irrigant extrusion in simulated immature permanent teeth when the apical diameter and needle insertion depth were varied. Thirty single-rooted maxillary incisors with straight root canals were selected. The root length was standardized to a length of 9 mm. The teeth were divided into two experimental groups according to the degree of apical enlargement (n = 15). The apices were enlarged to a diameter of 1.10 mm or 1.70 mm by using a #3 or #6 peeso reamer, respectively, to simulate immature teeth. The irrigation solution was applied 2 or 4 mm short of the working length (WL) in each experimental group. The glass vial model was used for the collection of extruded irrigant beyond the root apex. A two-way repeated measures analysis of variance test showed that there was no significant difference between different needle insertion depths (2 and 4 mm short of the WL) in the group with an apical diameter of 1.70 mm (p > 0.05). In the group with an apical diameter of 1.10 mm, a 32% increase in irrigant extrusion was observed when the needle was positioned at 2 mm (p < 0.05). Regarding the effect of apical diameter, the group with a diameter of 1.70 mm showed more apical extrusion of the irrigant (34% increase for the needle positioned at 2 mm and 68% increase for the needle positioned at 4 mm). It was observed that the needle insertion depth and apical diameter have a significant effect on irrigant extrusion in immature permanent teeth.

  9. An Evaluation of Various Permanent Restorative Materials’ Effect on the Shade of Bleached Teeth.

    DTIC Science & Technology

    1981-12-28

    O AD-Alt 9 628 ARMY INST OF DENTAL RESEARCH WASHINGTON DC F/G 6/5 AN EVALUATION OF VARIOUS PERMANENT RESTORATIVE MATER! S’ EFFFC--ETC (U) DEC A1 W F... Materials ’ Effect on the Shade of Bleached Teeth William F. Freccia, BS, DDS, MS Donald D. Peters, BA, DDS, MS Lewis Lorton, BA, DDS, MSD Commercial materials ...or that the materials and equip- ment are necessarily the best available for the purpose. The opinions contained herein are the private views of the

  10. Effect of bleaching agents on enamel surface of bovine teeth: A SEM study

    PubMed Central

    Pimenta-Dutra, Ana-Cristina; Albuquerque, Rodrigo-de Castro; Morgan, Luís-Fernando-dos Santos-Alves; Pereira, Geraldo-Magela; Nunes, Eduardo; Horta, Martinho-Campolina-Rebello

    2017-01-01

    Background This study aimed to evaluate changes in the enamel surface of bovine teeth after whitening with exogenous bleaching agents: 10% carbamide peroxide (group 1), 16% carbamide peroxide (group 2) and 35% hydrogen peroxide activated by a light-emitting diode (LED) (group 3). The evaluations were performed by scanning electron microscopy (SEM). Material and Methods Ninety bovine teeth were divided into five groups (n = 18). The bleaching agents 10% and 16% carbamide peroxide were applied for eight hours a day for 14 consecutive days. The third agent, LED-activated 35% hydrogen peroxide, was used four times at seven-day intervals. Each of the four time points consisted of three applications of 10 minutes each. A 37% phosphoric acid solution and artificial saliva were used as positive and negative controls, respectively. Results The evaluations by SEM showed changes in the enamel surfaces of the specimens. Based on the Mann-Whitney statistical test, the data showed significant differences (p<0.05) between groups 1 and 2 and between groups 2 and 3. However, no significant difference (p>0.05) was observed between groups 1 and 3. Conclusions Based on these results, it can be concluded that bleaching agents can cause changes in the structure of tooth enamel and that these changes are related to the concentration and the duration of contact with the tooth surface. Key words:Bovine teeth, carbamide peroxide, enamel, hydrogen peroxide, scanning electronic microscopy. PMID:28149462

  11. Comparative Gene Expression Analysis of the Human Periodontal Ligament in Deciduous and Permanent Teeth

    PubMed Central

    Kim, Seong-Oh; Jeon, Mijeong; Choi, Byung-Jai; Jung, Han-Sung; Moon, Seok Jun; Park, Wonse; Choi, Hyung-Jun

    2013-01-01

    There are histological and functional differences between human deciduous and permanent periodontal ligament (PDL) tissues. The aim of this study was to determine the differences between these two types of tissue at the molecular level by comparing their gene expression patterns. PDL samples were obtained from permanent premolars (n = 38) and anterior deciduous teeth (n = 31) extracted from 40 healthy persons. Comparative cDNA microarray analysis revealed several differences in gene expression between the deciduous and permanent PDL tissues. These findings were verified by qRT-PCR (quantitative reverse-transcription–polymerase chain reaction) analysis, and the areas where genes are expressed were revealed by immunohistochemical staining. The expressions of 21 genes were up-regulated in deciduous relative to PDL tissues, and those of 30 genes were up-regulated in permanent relative to deciduous PDL tissues. The genes that were up-regulated in deciduous PDL tissues were those involved in the formation of the extracellular matrix (LAMC2, LAMB3, and COMP), tissue development (IGF2BP, MAB21L2, and PAX3), and inflammatory or immune reactions leading to tissue degradation (IL1A, CCL21, and CCL18). The up-regulated genes in permanent PDL tissues were related to tissue degradation (IL6 and ADAMTS18), myocontraction (PDE3B, CASQ2, and MYH10), and neurological responses (FOS, NCAM2, SYT1, SLC22A3, DOCK3, LRRTM1, LRRTM3, PRSS12, and ARPP21). The analysis of differential gene expressions between deciduous and permanent PDL tissues aids our understanding of histological and functional differences between them at the molecular level. PMID:23593441

  12. Pulp Revascularization on Permanent Teeth with Open Apices in a Middle-aged Patient.

    PubMed

    Wang, Yu; Zhu, Xiaofei; Zhang, Chengfei

    2015-09-01

    Pulp revascularization is a promising procedure for the treatment of adolescents' immature permanent teeth with necrotic pulp and/or apical periodontitis. However, the ability to successfully perform pulp revascularization in a middle-aged patient remains unclear. A 39-year-old woman was referred for treatment of teeth #20 and #29 with necrotic pulp, extensive periapical radiolucencies, and incomplete apices. Pulp revascularization procedures were attempted, including root canal debridement, triple antibiotic paste medication, and platelet-rich plasma transplantation to act as a scaffold. Periapical radiographic and cone-beam computed tomographic examinations were used to review the changes in the apical lesions and root apex configuration. The patient remained asymptomatic throughout the 30-month follow-up. Periapical radiographic examination revealed no change in the apical lesions of either tooth at 8 months. The periapical radiolucency disappeared on tooth #20 and significantly decreased on tooth #29 by the 30-month follow-up, findings that were also confirmed by cone-beam computed tomographic imaging. No evidence of root lengthening or thickening was observed. Successful revascularization was achieved in a middle-aged patient's teeth.

  13. Clinical and Radiographic Outcomes of Traumatized Immature Permanent Necrotic Teeth after Revascularization/Revitalization Therapy

    PubMed Central

    Saoud, Tarek Mohamed A.; Zaazou, Ashraf; Nabil, Ahmed; Moussa, Sybel; Lin, Louis M.; Gibbs, Jennifer L.

    2014-01-01

    Introduction Revascularization treatment is rapidly becoming an accepted alternative for the management of endodontic pathology in immature permanent teeth with necrotic dental pulps. However, the success and timing of clinical resolution of symptoms and of radiographic outcomes of interest, such as continued hard tissue deposition within the root, are largely unknown. Methods In this prospective cohort study, 20 teeth were treated with a standardized revascularization treatment protocol, and monitored for clinical and radiographic changes for one year. Standardized radiographs were collected at regular intervals and radiographic changes were quantified. Results All 20 treated teeth survived during the 12 month follow up period and all 20 also met the clinical criteria for success at 12 months. As a group, the treated teeth demonstrated a statistically significant increase in radiographic width and length, and a decrease in apical diameter, although the changes in many cases were quite small such that the clinical significance is unclear. The within-case percent change in apical diameter after 3 months was 16% and had increased to 79% by 12 months, with 55% (11/20) showing complete apical closure. The within-case percent change in root length averaged less than 1% at 3 months and increased to 5% at 12 months. The within-case percent change in root thickness averaged 3% at 3 months and 21% at 12 months. Conclusions Although clinical success was highly predictable with this procedure, clinically meaningful radiographic root thickening and lengthening is less predictable at one year of follow up. Apical closure is the most consistent radiographic finding. PMID:25443280

  14. Prevalence of enamel defects in primary and permanent teeth in a group of schoolchildren from Granada (Spain)

    PubMed Central

    Robles, Maria J.; Bravo-Perez, Manuel; González, Encarnación; Peñalver, Maria A.

    2013-01-01

    Objective: The purpose of this study was to determine and compare the prevalence and presentations of developmental defects of the enamel (DDE) in the primary and permanent dentitions of a group of healthy schoolchildren residing in Granada (Spain). Study Design: A total of 1,414 healthy schoolchildren were examined using modified DDE criteria for recording enamel defects. Results: The prevalence of DDE of any type was 40.2% in primary dentition and 52% in permanent dentition (p<0.033). Of the 31,820 primary and permanent teeth examined in the study, 699 (4.1%) primary and 1,232 (8.3%) permanent teeth had some form of DDE. Diffuse opacity was the most common type of DDE observed in primary teeth, and demarcated opacity in the permanent teeth. Enamel hypoplasia was the least prevalent defect in both dentition types. Conclusions: The study population showed a high prevalence of DDE in primary as well as in permanent dentition, reflecting the current increasing trend of this condition, which should be considered as a significant public health problem. Key words:Developmental enamel defects, enamel hypoplasia, demarcated opacity, diffuse opacity. PMID:23229271

  15. Vertical root fracture resistance of simulated immature permanent teeth filled with MTA using different vehicles

    PubMed Central

    Askerbeyli-Örs, Sevinc; Deniz-Sungur, Derya

    2017-01-01

    Background The aim of the study is to evaluate the resistance vertical root fracture (VRF) of mineral trioxide aggregate (MTA) filled-immature permanent roots by using three different vehicles. Material and Methods Forty-extracted human single-rooted mandibular premolars were selected and the root length was standardized to the length of 9 mm. For simulation of immature tooth apices, peeso reamers were introduced into the root canals and the prepared roots were assigned into three experimental groups according the used vehicle (distilled water-DW, prophylene glycol-PG, chlorhexidine-CHX) and control group (n=10). To simulate a periodontal membrane, the apical 7 mm of all roots was covered with wax to obtain a 0.2- to 0.3-mm-thick layer before embedding the roots into acrylic cylinders. A vertical force was applied (1mm/min) using a universal testing machine and the maximum load (F-max) that fracture occurred and the fracture mode (splint or comminuted) was recorded. Data were presented as mean and standard deviations. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney U Test was used for multiple comparisons. Results There were significant differences between fracture strength of experimental groups with that of control group (p<0.05). However, no statistically significant differences were found amongst the fracture strength values of the experimental groups (p>0.05). In all groups, split fracture was the most common fracture mode. Conclusions MTA increases resistance of immature permanent teeth to VRF. Based on the results of this study, it can be concluded that mixing MTA with CHX or PG as the vehicle do not alter VRF resistance of simulated immature permanent roots. Key words:Immature teeth, MTA, vehicle, vertical root fracture. PMID:28210431

  16. The combined effect of xylitol and fluoride in varnish on bovine teeth surface microhardness.

    PubMed

    Vongsavan, Kadkao; Surarit, Rudee; Rirattanapong, Praphasri

    2014-03-01

    The aim of this study was to evaluate the combined effect of xylitol and fluoride in varnish on bovine tooth surface microhardness. Thirty caries-free bovine teeth were sectioned and embedded in self-cured acrylic resin and the buccal enamel surfaces were ground flat. Each tooth was then placed in demineralization solution for 40 hours. After demineralization, the teeth were randomly divided into 3 equal groups: group 1 was the control group (no treatment); group 2 was treated with fluoride varnish (Duraphat); group 3 was treated with a xylitol and fluoride varnish (Flor-Opal). All the specimens were then subjected to pH-cycling for 7 days, consisting of demineralization for 6 hours and remineralization for 18 hours repeated daily for five days followed by remineralization for 2 days. Surface microhardness was checked in each tooth at baseline, after demineralization and after pH-cycling. The results were recorded and the data were analyzed with the one-way ANOVA and Tukey tests. A p-value < 0.05 was considered significant. The mean surface microhardness values of the teeth treated with the fluoride varnish and the fluoride with xylitol varnish were not significantly different from each other and showed significantly better remineralization than control group. The fluoride and xylitol varnish combination was beneficial for preventing enamel demineralization but no better than in fluoride varnish alone in vitro. Adding xylitol to fluoride tooth varnish does not appear to give any significant benefit in vitro.

  17. Sealing Ability of MTA Used in Perforation Repair of Permanent Teeth; Literature Review

    PubMed Central

    Baroudi, Kusai; Samir, Samah

    2016-01-01

    There were several materials used to seal different types of perforation defects. MTA is one of these restorative materials that is considered the most effective, biocompatible, non-toxic, and non-irritant; promote bone healing and cementum regeneration. The objective of this article was to review and summarize the sealing ability of MTA compared with the other materials used for sealing different types of root perforations of permanent teeth. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2005 to 2015 searching for articles related to sealing ability of MTA. This study found that factors affecting prognosis are the size, site of the perforation and time elapsed as well as the repair material. MTA is an important filling material to be used for sealing different types of perforations when perforated sites sealed immediately with MTA. PMID:27347231

  18. Sealing Ability of MTA Used in Perforation Repair of Permanent Teeth; Literature Review.

    PubMed

    Baroudi, Kusai; Samir, Samah

    2016-01-01

    There were several materials used to seal different types of perforation defects. MTA is one of these restorative materials that is considered the most effective, biocompatible, non-toxic, and non-irritant; promote bone healing and cementum regeneration. The objective of this article was to review and summarize the sealing ability of MTA compared with the other materials used for sealing different types of root perforations of permanent teeth. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2005 to 2015 searching for articles related to sealing ability of MTA. This study found that factors affecting prognosis are the size, site of the perforation and time elapsed as well as the repair material. MTA is an important filling material to be used for sealing different types of perforations when perforated sites sealed immediately with MTA.

  19. [The effect of Kaviner and the smear layer on dentin permeability of permanent teeth in children].

    PubMed

    Tadmiscija, H; Kobaslija, S; Ganibegović, M; Jusufagić, H; Huseinbegović, A

    1996-01-01

    The dentin permeability is defined as a moving of fluid, of chemical substances and microbial products as well through the dentin. The clinical protection of children permanent teeth in other words the protection of pulp-dentin complex after their preparation makes a big problem into the restorative stomatology. Caviner is one of the newer means which is used in the protection of pulp-dentin complex which represents the components of powder dispersing within the ethyl-acetate mixture of polystirol. The important variable in this study is the presence or absence of smearing layer which has the important influence onto the dentin permeability. In order to confirm the Caviner and smearing layer working onto the dentin permeability of the children permanent teeth in vitro experiment was designed. We used for it the dentin disks made of the intact first premolar, extracted because of orthodontic reasons at the ten years old children. They were put into the split chamber which represents a part of apparatus made at our Faculty, which is, in fact, a modified apparatus which was formed by prof. D.H. Pashley (Georgia, USA), and it is used for measuring of dentin permeability with the help of hydraulic conductance (Lp) of dentin. The dentin permeability is expressed by the hydraulic conductance term, but the measures are still expressed as the Lp percentage maximum because of better survey of results. Comparing the obtained results with the other authors results we have come to the similar conclusions, and that is in fact, that the smearing layer significantly reduces the dentin permeability, and that the Caviner, as the other layners, reduces the dentin permeability. If we compare the reduction of dentin permeability at the dentin covered with the smearing layer and with the Caviner, it has been noticed that the smearing layer reduces more significantly. It should be accented that the Caviner reduces the dentin permeability less than the most earlier researched means for

  20. Tooth mobility changes subsequent to root fractures: a longitudinal clinical study of 44 permanent teeth.

    PubMed

    Andreasen, Jens Ove; Ahrensburg, Søren Steno; Tsilingaridis, Georgios

    2012-10-01

    The purpose of this study was to analyze tooth mobility changes in root-fractured permanent teeth and relate this to type of interfragment healing (hard tissue healing (HT), interfragment healing with periodontal ligament (PDL) and nonhealing with interposition of granulation tissue (GT) because of pulp necrosis in the coronal fragment. Furthermore, the effect of age, location of the fracture on the root, and observation period on mobility values was analyzed. Mobility values were measured for 44 of 95 previous reported root-fractured permanent incisors. Mobility changes were measured with a Mühlemanns periodontometer and noninjured incisors served as controls. The mobility values represented the labial-lingual excursion of the root measured in μm when the tooth received a frontal and a palatal impact of 100 g force. In 18 cases of hard tissue healing (HT), a slightly increased mobility was seen after 3 months and 1 year, and a normalization of mobility value was usually found after 5 and 10 years. In 17 cases of PDL healing, generally a higher mobility was found in comparison with root fractures healing with hard tissue, and a consistent decrease in mobility value was found in the course of the 10 year observation period. A tendency for reduced mobility over time was found, a relation that could possibly be explained by the known general decrease in tooth mobility with increasing age. Finally, nine cases of nonhealing with initial interposition of granulation tissue (GT) because of pulp necrosis in the coronal fragment resulted in increasing mobility values possibly related to a lateral breakdown of the PDL in relation to the fracture line. In control teeth, a lowering of mobility was found over the course of a 10-year observation period. In conclusion, mobility changes appeared to reflect the radiographic healing stages and known age effects upon tooth mobility.

  1. Prevalence and Pattern of Accessory Teeth (Hyperdontia) in Permanent Dentition of Iranian Orthodontic Patients

    PubMed Central

    Amini, Fariborz; Rakhshan, Vahid; Jamalzadeh, Sanaz

    2013-01-01

    Abstract Background Awareness of hyperdontia pattern/prevalence can be useful in early diagnosis and prevention by general practitioners, pediatric dentists, and orthodontists. Since the previous results regarding the pattern of hyperdontia (supernumerary teeth) are controversial, this study aimed to assess this subject among Iranian orthodontic patients. Methods All approved panoramic radiographs of 3374 orthodontic patients (aged 10 to 20 years old) who had visited orthodontic departments of all Tehran dentistry universities and 10 private clinics during the years 1999-2009 were investigated to establish the prevalence/pattern of hyperdontia in permanent dentition (excluding third molars). The data were analyzed using a chi-square, a chi-square goodness-of-fit, and a Fisher exact test (α=0.05). Results Of the patients, 2012 were female and 1362 were male. The prevalence of hyperdontia was 0.72% (14 females [0.69% of females], 10 males [0.73% of males], female-to-male ratio=1:1.055). The difference between the genders was not significant (P = 0.896). No double or multiple supernumeraries were found. The most common accessory teeth were mesiodens (58.3%), maxillary laterals (25%), and maxillary premolars (16.7%). Hyperdontia was significantly more common (P=0.000) in maxilla (there was only one mandibular accessory tooth). It was more frequent in the anterior segment (P=0.000). However the occurrence was not significantly different between bimaxillary right and left quadrants (P=0.6). Conclusion Hyperdontia was more common in premaxilla, and the most common accessory tooth was mesiodens. Unlike earlier studies, no bilateral accessory teeth were found. Also no gender dimorphism was discerned. PMID:26171338

  2. Genetic determinants and dynamics of permanent teeth emergence in Northwest Indian twins: a chronogenetic study.

    PubMed

    Sharma, Krishan

    2014-12-01

    The understanding of the role of genetic factors in phenotypic variation in the emergence of secondary teeth in humans remains is incomplete. Dental emergence data based on a mixed longitudinal study were collected on 111 twin pairs from an urban population of Chandigarh. The observations over time on a single individual varied from one to nine, thus giving a total of 595 entities. Female twins manifested emergence priority over males. The differences between zygosities in mean emergence ages were significant for only 6 of 16 (37%) instances. Magnitude of variations seen between twins and singletons in their mean emergence timings and duration of the hiatus between two dental phases of emergence were of the order observed among different samples from the same population/ethnic group. Heritability estimates for the specified number of the teeth emerged showed age variations. These estimates were highest in the first two age groups (from 5 to 7 years), when the first molars and incisors emerged. Maxilla-mandible differences were seen for tooth emergence timings and sequence patterns. Heritability for tooth emergence timings was higher in maxilla than in mandible. Multifactorial model of inheritance was the best fit model to explain variations observed in dental emergence timings and dental sequence pattern polymorphisms and there were significant genetic components of variation for both of these. There were sex differences in heritability; females had higher estimates than males. Genetic factors accounted for about 60% of the total phenotypic variation in the length of hiatus interval between two active stages of permanent teeth emergence.

  3. Health Instruction Packages: Permanent Teeth, Dental Deposits, and Dental Instruments. Dientes Permanentes, Depositos Dentales y Instrumentos Dentales.

    ERIC Educational Resources Information Center

    Lind, Patricia; Germano, Catherine

    These five learning modules use text interspersed with illustrations and reinforcement exercises to instruct dental aide and dental hygiene students about jaw bones and gums, dental deposits, and dental instruments. The first four modules were prepared by Patricia Lind in both Spanish and English. "The Gum and Bone of Permanent Teeth"…

  4. Multidisciplinary approach on rehabilitation of primary teeth traumatism repercussion on the permanent successor: 6-year follow-up case report.

    PubMed

    Mello-Moura, A C V; Bonini, G A V C; Suga, S S; Navarro, R S; Wanderley, M T

    2009-01-01

    Traumatic lesions in primary teeth are frequent in pediatric patients and can cause problems both to the deciduous tooth and permanent successor. The impact strength on deciduous tooth can reach the growing permanent tooth, affecting its morphology, structure and position, or even hampering its proper development. This report describes an aesthetic-functional rehabilitation process in an 8 year 10 month old boy during a multidisciplinary treatment held at the Clinical Center of Dental Trauma in Primary Teeth of the Pediatric Dentistry of Dental College of University of São Paulo, Brazil. The patient presented bilateral posterior cross bite and the permanent left upper central incisor with ectopic eruption and enamel hypoplasy, preceded by avulsion of element 61, occurred when the patient was 1.6 years old. After diagnosis and treatment planning, a quick expansion of jaws was recommended with Hass-type rapid expander and orthodontic leveling with fixed braces. Due to the ectopic eruption, the gingival contour had been altered and hypertrophia was found, compromising aesthetics and avoiding local hygienic procedures. Gingivoplasty was carried out with high-intensity Diode Laser, followed by aesthetic restoration with compound resin. It was concluded that after deciduous teeth traumatism it is important that the patient undergoes clinic and radiographic assistance until the permanent teeth erupt so that an adequate multidisciplinary treatment can be offered to the patient.

  5. Marginal Microleakage of Conventional Fissure Sealants and Self-Adhering Flowable Composite as Fissure Sealant in Permanent Teeth

    PubMed Central

    Rahimian-Imam, Sara; Fayazi, Mohammad Reza

    2015-01-01

    Objectives: Application of sealants is a safe and effective way to prevent occlusal caries in the posterior teeth. A successful sealant therapy depends on good isolation. Decreased steps of adhesive application may enable proper isolation and use of self-adhering flowable composites for sealant therapy. This study sought to compare the marginal microleakage of fissure sealants and self-adhering flowable composites in permanent teeth. Materials and Methods: This in vitro, experimental study was conducted on 60 extracted human premolar teeth. The teeth were divided randomly into two groups of 30. In the first group, fissure sealant (Clinpro, 3M ESPE, USA) was placed on the teeth. In the second group, self-adhering flowable composite (Vertise Flow, Kerr, USA) was applied as the sealant. Then, both groups were immersed in 0.5% fuchsin dye solution for 24 hours. Sectioned samples were observed with a stereomicroscope for the extent of dye penetration. Data were analyzed using SPSS 21 and the Mann-Whitney test (P<0.05). Results: Microleakage in the fissure sealant group was significantly higher than that in the self-adhering flowable composite group (P<0.001). Conclusion: Microleakage was less using self-adhering flowable composite compared to conventional fissure sealant; therefore, self-adhering flowable composite can be used as a suitable fissure sealant in permanent teeth. PMID:26884777

  6. Prevalence of sequelae in the permanent anterior teeth after trauma in their predecessors: a longitudinal study of 8 years.

    PubMed

    do Espírito Santo Jácomo, Diana Ribeiro; Campos, Vera

    2009-06-01

    The aim of this study was to determine the prevalence of sequelae in the permanent anterior teeth following trauma in their predecessors, and also to verify the existence of association between the sequelae in the permanent teeth and the type of injury in their predecessors according to the age group at the time of injury. This study was performed based on data from the records of 169 boys and 138 girls who received assistance at the dental clinic of the State University of Rio de Janeiro from March 1996 to December 2004. The sample was collected from 753 traumatized deciduous teeth of children aged 0-10 years. The number of boys and girls with dental trauma corresponded to 55.0% and 45.0%, respectively. The more affected age period was between 1 and 4 years (75.3%). The most common type of traumatic injury was the intrusion (29.3%), followed by avulsion (14.1%). Concerning permanent dentition, the most common developmental disturbances were discoloration of enamel and/or enamel hypoplasia (46.08%) and eruption disturbances (17.97%) due to the traumatic injury in their predecessors. It was not possible to find an association between the type of injury in primary teeth and sequelae in their successors in the studied age groups (P permanent dentition and that there was no significant statistical association between the occurrence of sequelae in the permanent teeth and the type of traumatic injury in their predecessors in the studied age groups.

  7. Teething

    MedlinePlus

    ... provider. Tips to ease your child's teething discomfort: Wipe your baby's face with a cloth to remove the drool ... NOT use homeopathic remedies, as they may contain ingredients that are not safe for infants.

  8. Teething.

    PubMed

    Leung, A K

    1989-02-01

    Teething does not appear to cause diarrhea, fever, rashes, seizures or bronchitis. It may be associated with some daytime restlessness, thumb sucking, gum rubbing, drooling and temporary loss of appetite. It is not clear whether these signs are developmental in origin or are actually related to tooth eruption. Illness occurring with teething should be thoroughly evaluated so that a serious systemic disturbance is not overlooked.

  9. An evaluation of microleakage of various glass ionomer based restorative materials in deciduous and permanent teeth: An in vitro study

    PubMed Central

    Singla, Teena; Pandit, I.K.; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

    2011-01-01

    Aim To evaluate the microleakage of recently available glass ionomer based restorative materials (GC Fuji IX GP, GC Fuji VII, and Dyract) and compare their microleakage with the previously existing glass ionomer restorative materials (GC Fuji II LC) in primary and permanent teeth. Method One hundred and fifty (75 + 75) non-carious deciduous and permanent teeth were restored with glass ionomer based restorative materials after making class I cavities. Samples were subjected to thermocycling after storing in distilled water for 24 h. Two coats of nail polish were applied 1 mm short of restorative margins and samples sectioned buccolingually after storing in methylene blue dye for 24 h. Microleakage was assessed using stereomicroscope. Result Significant differences (P < 0.05) were found when inter group comparisons were done. Except when GC Fuji VII (Group III) was compared with GC Fuji II LC (Group II) and Dyract (Group IV), non-significant differences (P > 0.05) were observed. It was found that there was no statistically significant difference when the means of microleakage of primary teeth were compared with those of permanent teeth. Conclusions GC Fuji IX GP showed maximum microleakage and GC Fuji VII showed least microleakage. PMID:23960526

  10. The effect of low-level laser therapy (810 nm) on root development of immature permanent teeth in dogs.

    PubMed

    Fekrazad, Reza; Seraj, Bahman; Ghadimi, Sara; Tamiz, Parvin; Mottahary, Pouriya; Dehghan, Mohammad-Mehdi

    2015-05-01

    Traumatic injuries and dental caries can be a big challenge to immature teeth. In these cases, the main purpose of treatment is to maintain the pulp vitality. The purpose of this study was to investigate the effect of low-level laser therapy on accelerating the rate of dentinogenesis in pulpotomy of immature permanent teeth (apexogenesis). Three dogs, 4-6 months old, were used in this study. One jaw in each dog was randomly assigned to laser irradiation group. All selected teeth were pulpotomized with mineral trioxide aggregate (MTA) and restored with amalgam. In the laser group, the Ga-Al-As laser (810 nm, 0.3 W, 4 J/cm(2), 9 s) was used on buccal and lingual gingiva of each tooth in 48 h intervals for 2 weeks. In order to observe the newly formed dentine, tetracycline was injected on the 1st, 3rd, 7th, and 14th day after the operation. Then, ground sections of teeth were observed under a fluorescence microscope. The data was analyzed with Generalized Estimating Equations (GEE) test. The mean distance between the lines of tetracycline formed on the 1st and 14th day was significantly higher in the laser group (P = 0.005). Within the limitation of this study, irradiation of Ga-Al-As laser (810 nm) can accelerate the rate of dentinogenesis in apexogenesis of immature permanent teeth with MTA in dogs.

  11. Comparative study of substance P and neurokinin A in gingival crevicular fluid of healthy and painful carious permanent teeth

    PubMed Central

    Heidari, Alireza; Shahrabi, Mahdi; Rokouei, Mehrak; Amirzargar, Aliakbar; Rahbar, Pegah

    2017-01-01

    Background: It is shown that neuropeptides can be transported from pulp chamber to periodontal ligament through apical foramen and accessory canals. Therefore, clinical pulpal pain leads to expression of preinflammatory neuropeptides such as substance P (SP) and neurokinin A (NKA) in gingival crevicular fluid (GCF). This study aimed to evaluate levels of SP and NKA in GCF of carious and healthy permanent teeth, comparatively. Materials and Methods: This cross-sectional study was performed on twenty children referred to Department of Pediatric Dentistry, Tehran University of Medical Sciences, who had a painful permanent first molar. Sampling was done by sterile paper cone from GCF of the mentioned teeth and the intact tooth of the other side of the jaw in the same patient. Values of SP and NKA were measured by ELISA test. Results: The mean concentration of SP in GCF of painful carious and healthy teeth was 2.65 ± 0.56 and 1.83 ± 0.65 pcgr/ml, respectively. This value was 2.29 ± 0.29 and 1.61 ± 0.35 pcgr/ml for NKA concentration in carious and healthy teeth as well. Conclusion: Significant higher levels of both SP and NKA in GCF of painful carious teeth were observed, which is in line with previous studies’ findings. PMID:28348619

  12. Teeth number anomalies in permanent dentition among non-syndromic dental patients.

    PubMed

    Aslan, Belma Işik; Akarslan, Zühre Zafersoy

    2013-03-01

    The aim of this study was to establish teeth number anomalies in relation to gender, tooth type, location, distribution pattern and the association between frequently missing teeth among a group of dental patients in Turkey. A total of 378 non-syndromic patients (240 females and 138 males) with an age range of 7-45 (x +/- SD = 22.07 +/- 3.6) having evidence of absent or excess teeth were evaluated in the study. Pearson Chi-square, Fisher's exact, McNemar and Kappa coefficients were used for statistical analysis. 237 patients had a total of 546 congenitally missing teeth and 141 had 185 excess teeth. Congenitally missing teeth were more commonly seen rather than the presence of supernumerary teeth. Difference was determined in the frequent locations of congenital missing and supernumerary teeth. The most frequent missing tooth type was found to be the mandibular second premolar (26.6%), while the majority of supernumerary teeth were located in the anterior region of the maxillary arch (37.9%). Both teeth number anomalies were more commonly seen among females. In hypodontia cases the occurrence of symmetrical agenesis of laterals and second premolars in maxilla; centrals and second premolars in mandible was notable. Agenesis of mandibular centrals was found to be associated with maxillary lateral agenesis in males. Also higher prevalence of molar teeth agenesis was determined in the occurrence of at least 4 teeth agenesis. These findings will serve as information about the contemporary demographic pattern of teeth number anomalies among non-syndromic Turkish dental patients and can provide evidence that agenesis of some teeth symmetrically or together are the products of the same genetic mechanisms.

  13. Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique.

    PubMed

    Camargo, Samira Esteves Afonso; Valera, Marcia Carneiro; Camargo, Carlos Henrique Ribeiro; Gasparoto Mancini, Maria Nadir; Menezes, Marcia Maciel

    2007-09-01

    This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 microg) and human (2.27 +/- 0.41 microg) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth.

  14. Micro-computed tomographic analysis of progression of artificial enamel lesions in primary and permanent teeth after resin infiltration.

    PubMed

    Ozgul, Betul Memis; Orhan, Kaan; Oz, Firdevs Tulga

    2015-09-01

    We investigated inhibition of lesion progression in artificial enamel lesions. Lesions were created on primary and permanent anterior teeth (n = 10 each) and were divided randomly into two groups with two windows: Group 1 (window A: resin infiltration; window B: negative control) and Group 2 (window A: resin infiltration + fluoride varnish; window B: fluoride varnish). After pH cycling, micro-computed tomography was used to analyze progression of lesion depth and changes in mineral density. Resin infiltration and resin infiltration + fluoride varnish significantly inhibited progression of lesion depth in primary teeth (P < 0.05). Inhibition of lesion depth progression in permanent teeth was significantly greater after treatment with resin infiltration + fluoride varnish than in the negative control (P < 0.05). Change in mineral density was smaller in the resin infiltration and resin infiltration + fluoride varnish groups; however, the difference was not significant for either group (P > 0.05). Resin infiltration is a promising method of inhibiting progression of caries lesions.

  15. Prediction of canine and premolar size using the widths of various permanent teeth combinations: A cross-sectional study

    PubMed Central

    Vanjari, Kalasandhya; Nuvvula, Sivakumar; Kamatham, Rekhalakshmi

    2015-01-01

    Aims: To suggest the best predictor/s for determining the mesio-distal widths (MDWs) of canines (C) and premolars (Ps), and propose regression equation/s for hitherto unreported population. Methods: Impressions of maxillary and mandibular arches were made for 201 children (100 boys and 101 girls; age range: 11–15 years) who met the inclusion criteria and poured with dental stone. The maximum MDWs of all the permanent teeth were measured using digital vernier caliper. Thirty-three possible combinations (patterns) of permanent maxillary and mandibular first molars, central and lateral incisors were framed and correlated with MDWs of C and Ps using Pearson correlation test. Results: There were significant correlations between the considered patterns and MDWs of C and Ps, with difference noted between girls (range of r: 0.34–0.66) and boys (range of r: 0.28–0.77). Simple linear and multiple regression equations for boys, girls, and combined sample were determined to predict MDW of C and Ps in both the arches. Conclusions: The accuracy of prediction improved considerably with the inclusion of as many teeth as possible in the regression equations. The newly proposed equations based on the erupted teeth may be considered clinically useful for space analysis in the considered population. PMID:26604576

  16. Mineral trioxide aggregate (MTA) apexification: a novel approach for traumatised young immature permanent teeth

    PubMed Central

    Vijayran, Manisha; Chaudhary, Seema; Manuja, Naveen; Kulkarni, Adwait Uday

    2013-01-01

    Here, we report a case of 9-year-old boy who came with a chief complaint of pain and fractured upper front teeth. Significant history of trauma was revealed 6 months before reporting, during playing at his school time. Proper diagnosis was made with the help of radiological investigations. The available treatment options were discussed with the patient's parents and root canal therapy, using mineral trioxide aggregate, as an apical barrier was carried out in his upper right front teeth. However, later on, the boy was aesthetically rehabilitated in relation to his fractured upper front teeth with the help of post and core and acrylic crown. PMID:23314456

  17. Posttraumatic displacement management: lateral luxation and alveolar bone fracture in young permanent teeth with 5 years of follow-up.

    PubMed

    Honório, Heitor Marques; de Alencar, Catarina Ribeiro Barros; Pereira Júnior, Edmer Silvestre; de Oliveira, Daniela Silva Barroso; de Oliveira, Gabriela Cristina; Rios, Daniela

    2015-01-01

    Dental trauma is an important public health problem due to high prevalence and associated limitations. The external impact accounting for trauma may result in different injury types to teeth and supporting structures. This paper describes a clinical case of tooth trauma in an 8-year-old patient exhibiting the displacement of three permanent teeth with open root apexes. Although the traumatic impact resulted in two injury types to teeth and supporting tissues (lateral luxation and alveolar bone fracture), the therapeutic approach was the same in both situations. The bone and teeth were repositioned by digital pressure, stabilized by semirigid splint, and followed up at every week. After six weeks, the splint was removed. At that moment, the clinical and radiographic findings indicated normal soft/hard tissues and absence of pulp/periodontal pathologies. At the fifth year of follow-up, the treatment success of the case was confirmed, although it has been observed that all lower incisors exhibited pulp obliteration as a consequence of the dental trauma.

  18. Comparison of lead levels in human permanent teeth from Strasbourg, Mexico City, and rural zones of Alsace.

    PubMed

    Frank, R M; Sargentini-Maier, M L; Turlot, J C; Leroy, M J

    1990-01-01

    A comparative study of the mean lead concentrations in enamel and dentin of human premolars and permanent molars was conducted by means of a systematic sampling procedure with energy-dispersive x-ray fluorescence analysis. In a first series of analyses, no significant statistical differences in mean lead concentrations at various levels of enamel and dentin were noted between young patients of Strasbourg and those of small villages of Alsace, nor between elderly patients living in these two locations, despite the fact that motor traffic was significantly lower in the rural zones. However, in both locations, a significantly higher concentration of lead was observed in enamel and dentin in relation to age. In a second series of analyses, the mean lead concentrations of both dental hard tissues of premolars and permanent molars of young individuals from Strasbourg, rural Alsace, and Mexico City were compared. Significantly higher mean lead concentrations were found in enamel and dentin samples from Mexico City. This was most evident for inner coronal dentin (5.7 and 6.1 times greater than in teeth of Strasbourg and rural zones of Alsace, respectively) and for pulpal root dentin (6.9 and 8.9 times greater than in teeth of Strasbourg and rural zones of Alsace). It is proposed that the higher lead concentrations are related to the higher lead content of motor gasoline and to more intense traffic conditions. The dental hard tissues appear to be of value for the study of environmental lead pollution.

  19. Outcomes of vital pulp therapy in permanent teeth with different medicaments based on review of the literature

    PubMed Central

    Akhlaghi, Najmeh; Khademi, Abbasali

    2015-01-01

    Vital pulp therapy (VPT) is a biologic and conservative treatment modality to preserve the vitality and function of the coronal or remaining radicular pulp tissue in vital permanent teeth. A search was conducted via the Cochrane database, PubMed, MEDLINE, and Ovid for any articles with the criteria for “pulp-capping,” or “pulp-capping materials” and “VPT outcomes” from 1978 to mid 2014. All articles were evaluated and the valid papers were selected. The outcomes of various VPT techniques, including indirect pulp treatment, direct pulp treatment, partial pulpotomy, and complete pulpotomy in vital permanent teeth were extracted. Although various studies have different research approach, most studies noted a favorable treatment outcome. Mineral trioxide aggregate (MTA) appears to be more effective than calcium hydroxide (Ca(OH)2) for maintaining long-term pulp vitality after indirect and direct pulp-capping. However, it seems that the success rate for partial pulpotomy and pulpotomy with Ca(OH)2 is similar to MTA. PMID:26604953

  20. Comparison of lead levels in human permanent teeth from Strasbourg, Mexico City, and rural zones of Alsace

    SciTech Connect

    Frank, R.M.; Sargentini-Maier, M.L.; Turlot, J.C.; Leroy, M.J. )

    1990-01-01

    A comparative study of the mean lead concentrations in enamel and dentin of human premolars and permanent molars was conducted by means of a systematic sampling procedure with energy-dispersive x-ray fluorescence analysis. In a first series of analyses, no significant statistical differences in mean lead concentrations at various levels of enamel and dentin were noted between young patients of Strasbourg and those of small villages of Alsace, nor between elderly patients living in these two locations, despite the fact that motor traffic was significantly lower in the rural zones. However, in both locations, a significantly higher concentration of lead was observed in enamel and dentin in relation to age. In a second series of analyses, the mean lead concentrations of both dental hard tissues of premolars and permanent molars of young individuals from Strasbourg, rural Alsace, and Mexico City were compared. Significantly higher mean lead concentrations were found in enamel and dentin samples from Mexico City. This was most evident for inner coronal dentin (5.7 and 6.1 times greater than in teeth of Strasbourg and rural zones of Alsace, respectively) and for pulpal root dentin (6.9 and 8.9 times greater than in teeth of Strasbourg and rural zones of Alsace). It is proposed that the higher lead concentrations are related to the higher lead content of motor gasoline and to more intense traffic conditions. The dental hard tissues appear to be of value for the study of environmental lead pollution.

  1. 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.

  2. Pulp Revascularization of Immature Permanent Teeth: A Review of the Literature and a Proposal of a New Clinical Protocol

    PubMed Central

    Namour, Mélanie

    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. PMID:25383384

  3. Radiographic and Clinical Outcomes of the Treatment of Immature Permanent Teeth by Revascularization or Apexification: A Pilot Retrospective Cohort Study

    PubMed Central

    Alobaid, Adel S.; Cortes, Lina M.; Lo, Jeffery; Nguyen, Thuan T.; Albert, Jeffery; Abu-Melha, Abdulaziz S; Lin, Louis M.; Gibbs, Jennifer L.

    2014-01-01

    Introduction This retrospective cohort study compared clinical and radiographic outcomes of endodontic treatment performed in immature non-vital permanent teeth, by apexification (calcium hydroxide or apical barrier with Mineral Trioxide Aggregate (MTA)), versus revascularization. Methods A comprehensive chart review was performed to obtain a cohort of sequential previously completed cases with recalls. Clinical and radiographic data were collected for 31 treated teeth (19 revascularization and 12 apexification) with an average follow up time of 17 months and a recall rate of 63%. Tooth survival, success rate, and adverse events were analyzed. Changes in radiographic root length, width and area were quantified. Results The majority of treated teeth survived throughout the study period with 30/31 (97%) teeth surviving (18/19 (95%) revascularization, 12/12 apexification). Most cases were also clinically successful with 27/31 (87%) meeting criteria for success, (15/19 (78%) revascularization and 12/12 apexification; non-significant difference). A greater incidence of adverse events was observed in the revascularization group (8/19 (42%) versus 1/12 (11%) in apexification (Risk Ratio= 5.1, p=0.04, 95%CI (0.719, 35.48)). Although more revascularization cases than apexification cases demonstrated an increase in radiographic root area and width, the effect was not statistically significant. Conclusion In this study, revascularization was not superior to other apexification techniques in either clinical or radiographic outcomes. Studies with large subject cohorts, and long follow up periods are needed to evaluate outcomes of revascularization and apexification, while accounting for important co-variants relevant to clinical success. PMID:25069909

  4. Secretome Profiling of Periodontal Ligament from Deciduous and Permanent Teeth Reveals a Distinct Expression Pattern of Laminin Chains.

    PubMed

    Giovani, Priscila A; Salmon, Cristiane R; Martins, Luciane; Paes Leme, Adriana F; Rebouças, Pedro; Puppin Rontani, Regina M; Mofatto, Luciana S; Sallum, Enilson A; Nociti, Francisco H; Kantovitz, Kamila R

    2016-01-01

    It has been suggested that there are histological and functional distinctions between the periodontal ligament (PDL) of deciduous (DecPDL) and permanent (PermPDL) teeth. Thus, we hypothesized that DecPDL and PermPDL display differences in the constitutive expression of genes/proteins involved with PDL homeostasis. Primary PDL cell cultures were obtained for DecPDL (n = 3) and PermPDL (n = 3) to allow us to perform label-free quantitative secretome analysis. Although a highly similar profile was found between DecPDL and PermPDL cells, comparative secretome analysis evidenced that one of the most stickling differences involved cell adhesion molecules, including laminin subunit gamma 1 (LAMC1) and beta 2 (LAMB2). Next, total RNA and protein extracts were obtained from fresh PDL tissues of deciduous (n = 6) and permanent (n = 6) teeth, and Western blotting and qPCR analysis were used to validate our in vitro findings. Western blot analysis confirmed that LAMC1 was increased in DecPDL fresh tissues (p<0.05). Furthermore, qPCR data analysis revealed that mRNA levels for laminin subunit beta 1 (LAMB1), beta 3 (LAMB3), LAMC1, and gamma 2 (LAMC2) were higher in DecPDL fresh tissues, whereas transcripts for LAMB2 were increased in PermPDL (p<0.05). In conclusion, the differential expression of laminin chains in DecPDL and PermPDL suggests an involvement of laminin-dependent pathways in the control of physiological differences between them.

  5. Secretome Profiling of Periodontal Ligament from Deciduous and Permanent Teeth Reveals a Distinct Expression Pattern of Laminin Chains

    PubMed Central

    Giovani, Priscila A.; Salmon, Cristiane R.; Martins, Luciane; Paes Leme, Adriana F.; Rebouças, Pedro; Puppin Rontani, Regina M.; Mofatto, Luciana S.; Sallum, Enilson A.; Nociti, Francisco H.; Kantovitz, Kamila R.

    2016-01-01

    It has been suggested that there are histological and functional distinctions between the periodontal ligament (PDL) of deciduous (DecPDL) and permanent (PermPDL) teeth. Thus, we hypothesized that DecPDL and PermPDL display differences in the constitutive expression of genes/proteins involved with PDL homeostasis. Primary PDL cell cultures were obtained for DecPDL (n = 3) and PermPDL (n = 3) to allow us to perform label-free quantitative secretome analysis. Although a highly similar profile was found between DecPDL and PermPDL cells, comparative secretome analysis evidenced that one of the most stickling differences involved cell adhesion molecules, including laminin subunit gamma 1 (LAMC1) and beta 2 (LAMB2). Next, total RNA and protein extracts were obtained from fresh PDL tissues of deciduous (n = 6) and permanent (n = 6) teeth, and Western blotting and qPCR analysis were used to validate our in vitro findings. Western blot analysis confirmed that LAMC1 was increased in DecPDL fresh tissues (p<0.05). Furthermore, qPCR data analysis revealed that mRNA levels for laminin subunit beta 1 (LAMB1), beta 3 (LAMB3), LAMC1, and gamma 2 (LAMC2) were higher in DecPDL fresh tissues, whereas transcripts for LAMB2 were increased in PermPDL (p<0.05). In conclusion, the differential expression of laminin chains in DecPDL and PermPDL suggests an involvement of laminin-dependent pathways in the control of physiological differences between them. PMID:27149379

  6. Sexual dimorphism in teeth: discriminatory effectiveness of permanent lower canine size observed in a XVIIIth century osteological series.

    PubMed

    Pettenati-Soubayroux, Isabelle; Signoli, Michel; Dutour, Olivier

    2002-05-23

    Recent studies have shown that the most dimorphic tooth is the mandibular canine. We have carried out a study on a random sample of 146 skeletons dating from the plague outbreak in Marseilles (1722). We studied 1284 maxillary and 1432 mandibular permanent teeth. Sexual dimorphism was tested on 89 individuals. We selected a set of four dental indices and calculated the dimorphism percentage by ratio expression male/female. Dimorphic ranking was made, by allotting the first rank to the tooth presenting the highest dimorphism and the last rank to the one presenting the lowest ratio. Comparisons of means were made on both sexes (sex determined by post-cranial data) through a Student's test (t-test). We noted that lower canines and lateral incisor are the most interesting teeth in the dimorphic dental determination. The lower index presented the highest relative risk with RR = 1.56 [1.04-2.32]. In 58% of the cases, the lower dental index enabled a correct sex determination (determined on the basis of the post-cranial skeleton). These results showed the existence of a relative dental dimorphism (male > female mesiodistal diameters) with humans. In conclusion, this method, using dental measurements, may be used as an additional technique to determine sex on fragmentary adult skeletons, immature material, missing pieces or ambiguities on post-cranial remains.

  7. An assessment of coronal leakage of permanent filling materials in endodontically treated teeth: An in vitro study

    PubMed Central

    Shetty, Kishore; Habib, V. Ashiq; Shetty, S. Vidhyadhara; Khed, Jaishri N.; Prabhu, Vishnudas Dinesh

    2015-01-01

    Introduction: The present in vitro study was undertaken to evaluate and compare the sealing ability of hybrid composite, glass ionomer cement type II, silver amalgam and Ketac molar as permanent filling material in root canal treated teeth. Methodology: Hundred maxillary central incisors were selected for the study. After cleaning all the teeth, root canal treatment was carried out on all of them. The crown portion was cut-off at the cervical level. Three millimeter of coronal Gutta-percha was replaced by four different restorative materials. Then after thermocycling, samples were immersed in dye for 2 weeks. The amount of dye penetration was measured using stereomicroscope. Data were collected and analyzed statistically with ANOVA test and Student–Newman–Keuls test. Results: Coronal leakage was seen in all groups. Composite hybrid showed least amount of microleakage as compared to the other three experimental groups, and Ketac molar showed more leakage compared to other experimental groups. Conclusion: This study showed that hybrid composites offer better sealing ability compared to other materials tested in this study. PMID:26538928

  8. Fatigue resistance of bovine teeth restored with resin-bonded fiber posts: effect of post surface conditioning.

    PubMed

    Zamboni, Sandra C; Baldissara, Paolo; Pelogia, Fernanda; Bottino, Marco Antonio; Scotti, Roberto; Valandro, Luiz Felipe

    2008-01-01

    This study evaluated the effect of post surface conditioning on the fatigue resistance of bovine teeth restored with resin-bonded fiber-reinforced composite (FRC). Root canals of 20 single-rooted bovine teeth (16 mm long) were prepared to 12 mm using a preparation drill of a double-tapered fiber post system. Using acrylic resin, each specimen was embedded (up to 3.0 mm from the cervical part of the specimen) in a PVC cylinder and allocated into one of two groups (n = 10) based on the post surface conditioning method: acid etching plus silanization or tribochemical silica coating (30 pm SiO(x) + silanization). The root canal dentin was etched (H2PO3 for 30 seconds), rinsed, and dried. A multi-step adhesive system was applied to the root dentin and the fiber posts were cemented with resin cement. The specimens were submitted to one million fatigue cycles. After fatigue testing, a score was given based on the number of fatigue cycles until fracture. All of the specimens were resistant to fatigue. No fracture of the root or the post and no loss of retention of the post were observed. The methodology and the results of this study indicate that tribochemical silica coating and acid etching performed equally well when dynamic mechanical loading was used.

  9. In vitro antimicrobial activity of sodium hypochlorite, chlorhexidine gluconate and octenidine dihydrochloride in elimination of microorganisms within dentinal tubules of primary and permanent teeth.

    PubMed

    Tirali, Resmiye-Ebru; Bodur, Haluk; Ece, Gülden

    2012-05-01

    The aim of this study was to evaluate the effectiveness of different irrigation solutions at different time intervals for the elimination of E. faecalis and C. albicans penetrated into the dentine tubules of primary and permanent teeth in vitro. The 4 mm primary and permanent teeth sections were sterilized and contaminated with a mixture of E. faecalis and C. albicans strains. After the application of different irrigation solutions (Sodium hypochlorite, Chlorhexidine gluconate, Octenidine Dihydrochloride, saline) to the contaminated tooth sections according to study groups, neutralizers were applied for inactivation of the solutions after 30 sec, 1 min and 5 min. Dentine shavings were placed into TSB and 10 µL from each tube was inoculated on agar plates, followed by an incubation period of 24 h at 37°C. The colonies were counted macroscopically. The results were compared by using Kruskal-Wallis and Mann Whitney U tests, with a significance level at p<0.05. Among the irrigation solutions that were tested against E. faecalis on primary and permanent teeth, the most effective one was found as 5-minute application of 0.1% Octenidine Dihydrochloride. The antibacterial effects of the tested solutions on the same time periods against C. albicans revealed no significant difference. There were no statistically significant differences between primary and permanent teeth with respect to the antimicrobial activity of the tested solutions. Moreover, Octenidine Dihydrochloride may be used as an alternative endodontic irrigant.

  10. Distinguishing between enamel fluorosis and other enamel defects in permanent teeth of children

    PubMed Central

    Sabokseir, Aira

    2016-01-01

    Background. The inconsistent prevalence of fluorosis for a given level of fluoride in drinking water suggests developmental defects of enamel (DDEs) other than fluorosis were being misdiagnosed as fluorosis. The imprecise definition and subjective perception of fluorosis indices could result in misdiagnosis of dental fluorosis. This study was conducted to distinguish genuine fluorosis from fluorosis-resembling defects that could have adverse health-related events as a cause using Early Childhood Events Life-grid method (ECEL). Methods. A study was conducted on 400 9-year-old children from areas with high, optimal and low levels of fluoride in the drinking water of Fars province, Iran. Fluorosis cases were diagnosed on the standardized one view photographs of the anterior teeth using Dean’s and TF (Thylstrup and Fejerskov) Indices by calibrated dentists. Agreements between examiners were tested. Early childhood health-related data collected retrospectively by ECEL method were matched with the position of enamel defects. Results. Using both Dean and TF indices three out of four dentists diagnosed that 31.3% (115) children had fluorosis, 58.0%, 29.1%, and 10.0% in high (2.12–2.85 ppm), optimal (0.62–1.22 ppm), and low (0.24–0.29 ppm) fluoride areas respectively (p < 0.001). After matching health-related events in the 115 (31.3%) of children diagnosed with fluorosis, 31 (8.4%) of children had fluorosis which could be matched with their adverse health-related events. This suggests that what was diagnosed as fluorosis were non-fluoride related DDEs that resemble fluorosis. Discussion. The frequently used measures of fluorosis appear to overscore fluorosis. Use of ECEL method to consider health related events relevant to DDEs could help to differentiate between genuine fluorosis and fluorosis-resembling defects. PMID:26966672

  11. Radiopacity of different resin-based and conventional luting cements compared to human and bovine teeth.

    PubMed

    Pekkan, Gürel; Ozcan, Mutlu

    2012-02-03

    This study evaluated the radiopacity of different resin-based luting materials and compared the results to human and bovine dental hard tissues. Disc specimens (N=130, n=10 per group) (diameter: 6 mm, thickness: 1 mm) were prepared from 10 resin-based and 3 conventional luting cements. Human canine dentin (n=10), bovine enamel (n=10), bovine dentin (n=10) and Aluminium (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted and equivalent Al thickness values were determined for radiopacity measurements of each material. The radiopacity values of conventional cements and two resin luting materials (Rely X Unicem and Variolink II), were significantly higher than that of bovine enamel that could be preferred for restorations cemented on enamel. Since all examined resin-based luting materials showed radiopacity values equivalent to or greater than that of human and bovine dentin, they could be considered suitable for the restorations cemented on dentin.

  12. Influence of effective number of pulses on the morphological structure of teeth and bovine femur after femtosecond laser ablation.

    PubMed

    Nicolodelli, Gustavo; Lizarelli, Rosane de Fátima Zanirato; Bagnato, Vanderlei Salvador

    2012-04-01

    Femtosecond lasers have been widely used in laser surgery as an instrument for contact-free tissue removal of hard dental, restorative materials, and osseous tissues, complementing conventional drilling or cutting tools. In order to obtain a laser system that provides an ablation efficiency comparable to mechanical instruments, the laser pulse rate must be maximal without causing thermal damage. The aim of this study was to compare the different morphological characteristics of the hard tissue after exposure to lasers operating in the femtosecond pulse regime. Two different kinds of samples were irradiated: dentin from human extracted teeth and bovine femur samples. Different procedures were applied, while paying special care to preserving the structures. The incubation factor S was calculated to be 0.788±0.004 for the bovine femur bone. These results indicate that the incubation effect is still substantial during the femtosecond laser ablation of hard tissues. The plasma-induced ablation has reduced side effects, i.e., we observe less thermal and mechanical damage when using a superficial femtosecond laser irradiation close to the threshold conditions. In the femtosecond regime, the morphology characteristics of the cavity were strongly influenced by the change of the effective number of pulses.

  13. Study of Root Canal Anatomy in Human Permanent Teeth in A Subpopulation of Brazil's Center Region Using Cone-Beam Computed Tomography - Part 1.

    PubMed

    Estrela, Carlos; Bueno, Mike R; Couto, Gabriela S; Rabelo, Luiz Eduardo G; Alencar, Ana Helena G; Silva, Ricardo Gariba; Pécora, Jesus Djalma; Sousa-Neto, Manoel Damião

    2015-10-01

    The aim of this study was to evaluate the frequency of roots, root canals and apical foramina in human permanent teeth using cone beam computed tomography (CBCT). CBCT images of 1,400 teeth from database previously evaluated were used to determine the frequency of number of roots, root canals and apical foramina. All teeth were evaluated by preview of the planes sagittal, axial, and coronal. Navigation in axial slices of 0.1 mm/0.1 mm followed the coronal to apical direction, as well as the apical to coronal direction. Two examiners assessed all CBCT images. Statistical data were analyzed including frequency distribution and cross-tabulation. The highest frequency of four root canals and four apical foramina was found in maxillary first molars (76%, 33%, respectively), followed by maxillary second molars (41%, 25%, respectively). The frequency of four root canals in mandibular first molars was 51%. Mandibular first premolars had two root canals and two apical foramina in 29% and 20% of the cases, respectively. Mandibular central and lateral incisors and canines presented two root canals in 35%, 42% and 22% of the cases, respectively. The navigation strategy in CBCT images favors a better identification of frequency and position of roots, root canals and apical foramina in human permanent teeth.

  14. Combined Orthodontic-surgical Treatment for Skeletal Class III Malocclusion with Multiple Impacted Permanent and Supernumerary Teeth: Case Report

    PubMed Central

    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. PMID:24893948

  15. Radiopacity of different shades of resin-based restorative materials compared to human and bovine teeth.

    PubMed

    Pekkan, Gurel; Ozcan, Mutlu

    2012-01-01

    This study evaluated the radiopacity of different shades of resin-based restorative materials and compared the results to human and bovine dental hard tissues. Disk specimens 6 mm in diameter and 1 mm thick (N = 220, n = 10) were prepared from the following restorative materials: · eight shades of nanofilled composite (Aelite Aesthetic Enamel), · seven shades of nanohybrid composite (Grandio Universal), · six shades of photopolymerized polyacid modified compomer (Glasiosite), and · one shade of hybrid composite (X-tra fil U). Human canine dentin (n = 10), bovine enamel (n = 10), and an aluminum (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted, and equivalent Al thickness (eq Al) values were determined for radiopacity measurements of each material. The data were analyzed using a non-parametric one-way ANOVA (Kruskal-Wallis), and multiple comparisons were made with a Student-Newman-Keuls post hoc test (a = 0.05). Different shades of resin-based restorative materials tested did not reveal statistically significant differences within each material group (p > 0.05). Radiopacity values of the resin-based restorative materials investigated varied depending on their types; however, within different shades of one material type, radiopacity values were comparable. Every shade of nanocomposite material other than Aelite Aesthetic Enamel Incisal LT Gray showed comparable radiopacity to human dentin. Other materials tested demonstrated higher radiopacity compared to human dentin and bovine enamel.

  16. Keeping Your Child's Teeth Healthy

    MedlinePlus

    ... prevent decay by applying a thin wash of resin (called a sealant) to the back teeth, where ... permanent teeth. But now, other materials like composite resins are becoming popular. Resins bond to the teeth ...

  17. Diffusion analysis of one photosensitizer in bovine teeth using fluorescence optical imaging

    NASA Astrophysics Data System (ADS)

    Montanha, S.; Pratavieira, S.; Jacomassi, D. P.; Rastelli, A. N. S.; Bagnato, V. S.

    2012-01-01

    Some photosensitizers (PSs) used for PACT (Antimicrobial Photodynamic Therapy) show an affinity for bacterial walls and can be photo-activated to cause the desired damage. However, on dentine bacterias may be less susceptible to PACT as a result of limited penetration of the PS. The aim of this study was to evaluate the diffusion of one PS based on hematoporphyrin on dentine structures. Twelve bovine incisors were used. Class III cavities (3 x 3 x 1mm) were prepared on the mesial or distal surfaces using a diamond bur. Photogem® solution at 1 mg/mL (10 uL for each cavity) was used. The experimental Groups were divided according to thickness of dentine remaining and etched or no-etched before the PS application. The fluorescence excitation source was a VelScope® system. For image capture a scientific CCD color camera PixelFly® was coupled to VelScope. For image acquisition and processing, a computational routine was developed at Matlab®. Fick's Law was used to obtain the average diffusion coefficient of PS. Differences were found between all Groups. The longitudinal temporal diffusion was influenced by the different times, thickness and acid etching.

  18. Cone-beam computed tomography study of the root and canal morphology of mandibular permanent anterior teeth in a Chongqing population

    PubMed Central

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

    2016-01-01

    Objective To investigate the root and canal morphology of permanent mandibular anterior teeth in a Chongqing population using cone-beam computed tomography (CBCT). Methods CBCT images of 1,725 patients in a Chongqing population were selected, and a total of 9,646 mandibular anterior teeth were analyzed. The number of root canals and the canal configurations were investigated. Results In total, 0.3% (11/3,257) of lateral incisors and 0.8% (26/3,014) of canines had double roots, and 3.8% (127/3,375) of central incisors, 10.6% (345/3,257) of lateral incisors, and 4.2% (127/3,014) of canines had multi-root canals. The difference in the incidence of multi-canals in lateral incisors between female and male was statistically significant. The frequency of multi-canals in the different age groups was 5.0% for central incisors for ages 21–30 years, 14.7% for lateral incisors for ages 41–50 years, and 8.1% for canines for ages 41–50 years. Conclusion With the limitations of the current study, we found that a high percentage of mandibular anterior teeth had multiple canals in the studied Chinese Chongqing population. The current data may provide clinicians practicing in Chongqing with a more thorough understanding of root canal morphology. PMID:26730198

  19. Comparison of Clinical Success of Applying a Kind of Fissure Sealant on the Lower Permanent Molar Teeth in Dry and Wet Conditions

    PubMed Central

    Eskandarian, Tahereh; Baghi, Saeid; Alipoor, Abbas

    2015-01-01

    Statement of the Problem Fissure sealant therapy is among the most effective methods of preventing dental caries. However, it is lengthy and isolation of the teeth is difficult in this procedure especially in young children. Using new hydrophilic fissure sealant may reduce such problems. Purpose This study aimed to evaluate the clinical success of a hydrophilic fissure sealant on the lower permanent molar teeth in dry and wet conditions. Materials and Method This clinical trial assessed 31 patients (mean age 8.13±1.77 years) who needed fissure sealant therapy on their first or second mandibular permanent molar. Having performed dental prophylaxis, the teeth were etched and rinsed. Then one of the two was randomly selected and sealed with smartseal & loc in isolated and dry conditions; while, the other was wetted on the etched enamel by using a saliva-contaminated micro brush, and was then sealed with the same fissure as the first tooth. Six and 12 months later, two independent observers examined the clinical success of sealant through checking the marginal integrity, marginal discoloration, and anatomical form. Data were analyzed by using SPSS software, version 16. The bivariate Chi-square and Exact Fisher tests were used to compare the clinical success of the two treatment methods. Results There was a high interpersonal reliability between the two examiners (K= 0.713). After 12 months, 90.3% clinical success was observed in dry conditions and 83.9% in wet conditions for smartseal & loc; however, the difference was not statistically significant (p= 0.0707). Conclusion According to the results of this study, it seems that using new hydrophilic fissure sealant can reduce technical sensitivities and consequently decreases the apprehensions on saliva contamination of etched enamel during treatment procedures. PMID:26331144

  20. Immunohistological Evaluation of Revascularized Immature Permanent Necrotic Teeth Treated by Platelet-Rich Plasma: An Animal Investigation

    PubMed Central

    Moradi, Saeed; Talati, Ali; Forghani, Maryam; Jafarian, Amir Hossein; Naseri, Mandana; Shojaeian, Shiva

    2016-01-01

    Objective Pulp regeneration within the root canal of necrotic teeth is considered an ideal treatment to allow for continued root development and recover teeth vitality. This study aims to evaluate the inductive effect of platelet-rich plasma (PRP) on expression of angiogenesis factors and pulpal revascularization of immature necrotic teeth. Materials and Methods In this experimental animal study, we randomly divided 28 immature premolars from two mixed breed dogs into four groups, two experimental, negative and a positive control. Premolars in negative control group were left intact to develop normally. In the positive control and experimental groups, we removed the pulps and induced pulp necrosis, after which the chambers were sealed. Then, we applied the revascularization protocol in the experimental teeth located in the right quadrant. Two months later, the same protocol was applied to the left quadrant. The root canals were disinfected by irrigation with sodium hypochlorite (NaOCl) solution and application a triple antibiotic past. Following the induction of a blood clot (BC) inside the canal space, the coronal portion of the canals was assigned to either of two experimental groups: group 1 [BC+PRP+ mineral trioxide aggregate (MTA)], group 2 (BC+MTA). Access cavities were sealed with a Glass Ionomer. The jaws that held the teeth were processed for histologic analysis of newly formed tissue and immunohistochemical evaluation according to vascular endothelial growth factor (VEGF) and factor VIII expressions in the canals. Results Histological analysis demonstrated no significant difference in the formation of new vital tissue inside the root canals between groups1 (42.8%) and 2 (43.5%, P>0.05). Based on immunohistochemical evaluation, micro-vessel density (MVD) of the granulation tissues in both groups were similar and were higher compared with the normal pulp. We observed strongly positive expressions of VEGF and factor VIII in the stromal and endothelial cells

  1. Influence of water-layer thickness on Er:YAG laser ablation of enamel of bovine anterior teeth.

    PubMed

    Mir, Maziar; Meister, Joerg; Franzen, Rene; Sabounchi, Shabnam S; Lampert, Friedrich; Gutknecht, Norbert

    2008-10-01

    Different ideas have been presented to describe the mechanism of augmented laser ablation of dental enamel with different shapes by adding water to the working environment. In this study, the influence of water-laser interaction on the surface of enamel during ablation was investigated at a wavelength of 2.94 microm with different distances between the laser tip and the enamel surface. A motion-control system was used to produce linear incisions uniformly on flat enamel surfaces of bovine anterior teeth, with free-running Er:YAG laser very short pulses (pulse length = 90-120 micros, repetition rate = 10 pulses per second). Four different output energies (100, 200, 300 and 400 mJ) were radiated on samples under distilled water from different distances (0.5, 0.75, 1, 1.25, 1.75 and 2.00 mm). The tooth slices were prepared with a cutting machine, and the surfaces of the ablated areas were measured with software under a light microscope. The average and standard deviation of all cut areas in different groups were reported. There was no significant difference when using a different pulse ablation speed (cm(3)/J) and a water-layer thickness between the tip and enamel surface of 0.5-1.25 mm with energy densities of 30-60 J/cm(2) (200-400 mJ). However, using an output energy of 15 J/cm(2) (100 mJ) and a thicker water layer than 1 mm, a linear ablation did not take place. This information led to a clearer view of the efficiency of Er:YAG laser in the conditions of this study. There are several hypotheses which describe a hydrokinetic effect of Er,Cr:YSGG. These basic studies could guide us to have a correct attitude regarding hydro-mechanical effects of water, although the wavelength of 2.78 microm has a better absorption in hydroxyl branch of water molecules. Therefore, our results do not directly interrupt with the series of investigations done with Er,Cr:YSGG. Water propagation and channel formation under water are investigated during the ablation of tooth enamel with

  2. Determination of Frequency of the Second Mesiobuccal Canal in the Permanent Maxillary First Molar Teeth with Magnification Loupes (× 3.5)

    PubMed Central

    Hasan, Muhammad; Raza Khan, Farhan

    2014-01-01

    INTRODUCTION: The mesiobuccal root of the maxillary first molar has generated more research and clinical investigation than any root. An inability to detect and treat a second mesiobuccal (MB2) canal is a reason for endodontic failure in maxillary first molars. Modifications in the endodontic access and detection techniques, along with advancements in illumination and magnification technology, have aided in the location and treatment with the second mesiobuccal canal of maxillary first molars. OBJECTIVE: To determine the frequency of the second mesiobuccal canal in the permanent maxillary first molars with magnification loupes (× 3.5). MATERIALS AND METHODS: A total of 53 teeth were assessed using a moderate magnification for second mesiobuccal canal in mesiobuccal root of first permanent maxillary molars in vivo. Detection of this canal in maxillary first molars was done through a clinical access cavity preparation under magnification loupes (× 3.5). Data was analyzed using SPSS 15.0. Frequency distribution of variables was determined and the level of significance was kept at 0.05. RESULTS: We were able to detect second mesiobuccal canal in 27 out of 53 (50.9%) of the permanent maxillary first molars that were studied. It was found that the males tend to have a higher proportion of second mesiobuccal canals (up to 31%) as compared to the females in whom the second mesiobuccal canals could be identified only 19% of the time. Whilst, there was no association found between age, gender and chamber obliteration with the presence of second mesiobuccal canal. CONCLUSIONS: In conclusion, within its limitations, this study suggested that the use of magnification loupes enhanced both the detection (50.9%) and negotiation (86.8%) of the second mesiobuccal canals in the permanent maxillary first molars beyond what could be achieved with naked eye. PMID:25324702

  3. Minimization of cogging torque in permanent magnet motors by teeth pairing and magnet arc design using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Eom, Jae-Boo; Hwang, Sang-Moon; Kim, Tae-Jong; Jeong, Weui-Bong; Kang, Beom-Soo

    2001-05-01

    Cogging torque is often a principal source of vibration and acoustic noise in high precision spindle motor applications. In this paper, cogging torque is analytically calculated using energy method with Fourier series expansion. It shows that cogging torque is effectively minimized by controlling airgap permeance function with teeth pairing design, and by controlling flux density function with magnet arc design. For an optimization technique, genetic algorithm is applied to handle trade-off effects of design parameters. Results show that the proposed method can reduce the cogging torque effectively.

  4. Immature permanent teeth with apical periodontitis and abscess treated by regenerative endodontic treatment using calcium hydroxide and MTA: a report of two cases.

    PubMed

    Park, Mirae; Ahn, Byung Duk

    2014-01-01

    Regenerative endodontic techniques have been introduced to overcome the limits of the traditional apexification approach and allow continued root development after treatment of infected immature permanent teeth. The purpose of this report was to describe two cases with severe apical periodontitis and abscess that were successfully treated by regenerative endodontic treatment using calcium hydroxide. The report involves treatment of two patients who developed apical periodontitis and abscesses on their immature premolars affected by dens evaginatus. Regenerative endodontic treatment was performed using calcium hydroxide. The treatment procedures have been shown to result in increased thickening of root walls and encourage continued root development. Different outcomes were observed when calcium hydroxide was placed past and within the coronal half of the canal. Calcium hydroxide can be used as an effective medicament in regenerative endodontic technique, and successful regeneration can be expected even in severe cases of apical periodontitis or abscess.

  5. A comparative evaluation of the blood clot, platelet-rich plasma, and platelet-rich fibrin in regeneration of necrotic immature permanent teeth: A clinical study

    PubMed Central

    Narang, Isha; Mittal, Neelam; Mishra, Navin

    2015-01-01

    Introduction: This study was designed as a clinical trial to evaluate and compare the regenerative potential of platelet-rich fibrin (PRF), platelet-rich plasma (PRP), and blood clot in immature necrotic permanent teeth with or without associated apical periodontitis. Methods: Access preparation was done under rubber dam isolation. Copious irrigation was done with 2.5% NaOCl and triple antibiotic paste was placed as an intracanal medicament. After 4 weeks, the cases were divided into four groups with five patients in each group. The study design had three test arms and one control arm. Group I in which mineral trioxide aggregate apexification was carried out and it was kept as control group to evaluate the regenerative potential of blood clot and platelet concentrates, Group II in which blood clot was used as scaffold in the canal, Group III in PRF was used as scaffold, and Group IV in which PRP carried on collagen was used as a scaffold. Results: The clinical and radiographic evaluation after 6 and 18 months was done by two independent observers who were blinded from the groups. The scoring was done as: None score was denoted by, Fair by 1, Good by 2, and Excellent by 3. The data were then analyzed statistically by Fisher's exact test using Statistics and Data 11.1(PRP Using harvest Smart PReP2) which showed statistically significant values in Group III as compared to other Groups. Conclusion: PRF has huge potential to accelerate the growth characteristics in immature necrotic permanent teeth as compared to PRP and blood clot. PMID:25684914

  6. Failure Rate of Direct High-Viscosity Glass-Ionomer Versus Hybrid Resin Composite Restorations in Posterior Permanent Teeth - a Systematic Review

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2015-01-01

    Purpose Traditionally, resin composite restorations are claimed by reviews of the dental literature as being superior to glass-ionomer fillings in terms of restoration failures in posterior permanent teeth. The aim of this systematic review is to answer the clinical question, whether conventional high-viscosity glass-ionomer restorations, in patients with single and/or multi-surface cavities in posterior permanent teeth, have indeed a higher failure rate than direct hybrid resin composite restorations. Methods Eight databases were searched until December 02, 2013. Trials were assessed for bias risks, in-between datasets heterogeneity and statistical sample size power. Effects sizes were computed and statistically compared. A total of 55 citations were identified through systematic literature search. From these, 46 were excluded. No trials related to high-viscosity glass-ionomers versus resin composite restorations for direct head-to-head comparison were found. Three trials related to high-viscosity glass-ionomers versus amalgam and three trials related to resin composite versus amalgam restorations could be included for adjusted indirect comparison, only. Results The available evidence suggests no difference in the failure rates between both types of restoration beyond the play of chance, is limited by lack of head-to-head comparisons and an insufficient number of trials, as well as by high bias and in-between-dataset heterogeneity risk. The current clinical evidence needs to be regarded as too poor in order to justify superiority claims regarding the failure rates of both restoration types. Sufficiently large-sized, parallel-group, randomised control trials with high internal validity are needed, in order to justify any clinically meaningful judgment to this topic. PMID:26962372

  7. Recombinant Amelogenin Protein Induces Apical Closure and Pulp Regeneration in Open-apex, Non-vital Permanent Canine Teeth

    PubMed Central

    Mounir, Maha M.F.; Matar, Moustafa A.; Lei, Yaping; Snead, Malcolm L.

    2015-01-01

    Introduction Recombinant DNA produced amelogenin protein was compared to calcium hydroxide in a study of immature apex closure conducted in 24 young mongrel dogs. Methods Root canals of maxillary and mandibular right premolars (n = 240) were instrumented and left open for 14 days. Canals were cleansed, irrigated and split equally for treatment with recombinant mouse amelogenin (n = 120) or calcium hydroxide (n = 120). Results After 1, 3, and 6 months, the animals were sacrificed and the treated teeth recovered for histological assessment and immunodetection of protein markers associated with odontogenic cells. After 1 month, amelogenin-treated canals revealed calcified tissue formed at the apical foramen and a pulp chamber containing soft connective tissue and hard tissue; amelogenin-treated canals assessed after 3 and 6 month intervals further included apical tissue functionally attached to bone by a periodontal ligament. In contrast, calcified apical tissue was poorly formed in the calcium hydroxide group and soft connective tissue within the pulp chamber was not observed. Conclusions The findings from this experimental strategy suggest recombinant amelogenin protein can signal cells to enhance apex formation in non-vital immature teeth and promote soft connective tissue regeneration. PMID:26709200

  8. Apical Extrusion of Irrigants in Immature Permanent Teeth by Using EndoVac and Needle Irrigation: An In Vitro Study

    PubMed Central

    Velmurugan, N; Sooriaprakas, C; Jain, Preetham

    2014-01-01

    Objective: Immature teeth have a large apical opening and thin divergent or parallel dentinal walls; hence, with conventional needle irrigation there is a very high possibility of extrusion. This study was done to compare the apical extrusion of NaOCl in an immature root delivered using EndoVac and needle irrigation. Materials and Methods: Eighty freshly extracted maxillary central incisors were decoronated followed by access cavity preparation. Modified organotypic protocol was performed to create an open apex; then, the samples were divided into four groups (n=20): EndoVac Microcannula (group I), EndoVac Macrocannula (group II), NaviTip irrigation needle (group III) and Max-i-Probe Irrigating needle (group IV); 9.0 ml of 3% sodium hypochlorite was delivered slowly over a period of 60 seconds. Extruded irrigants were collected in a vial and analysed statistically. Results: Group I, group III and group IV showed 100% extrusion (20/20) but group II showed only 40% extrusion (8/20). The difference in this respect between group II and other groups was statistically significant (P<0.001). With regards to the volume of extrusion, group II had only 0.23 ml of extruded irrigant. Group I extruded 7.53ml of the irrigant. Group III and group IV extruded the entire volume of irrigant delivered. Conclusion: EndoVac Macrocannula resulted in the least extrusion of irrigant in immature teeth when compared to EndoVac Microcannula and conventional needle irrigation. PMID:25584055

  9. COMPARISON OF CHILDREN'S FOLLOW-ON INSTANT POWDERED COW'S MILK FORMULA, BUFFALO MILK FORMULA AND CHICKEN-BASED FORMULA ON ENAMEL MICROHARDNESS OF BOVINE TEETH IN VITRO.

    PubMed

    Vongsavan, Kadkao; Rirattanapong, Praphasri; Surarit, Rudee

    2016-03-01

    Dental caries are a major public health problem worldwide. The aim of this study was to compare the effects of children's follow-on instant powdered cow's milk formula, buffalo milk formula and a chicken-based formula on microhardness of bovine enamel with artificial caries-like lesions. Forty bovine teeth were each placed in acrylic blocks and the enamel surfaces were polished to create flat 5 x 5 millimeter surfaces. The teeth surfaces were then demineralized using 0.1M lactic acid (pH 4.5) to achieve an enamel microhardness of 35-65 Vickers Hardness Numbers (VHN). All specimens were then randomly allocated into one of 4 groups (n=10/group). For remineralization, each group was soaked in a different kind of milk formula for 2 hours at 37°C except group 1 which was a negative control (artificial saliva) group. Group 2 was soaked in Murrah™ buffalo milk formula (a positive control ), group 3 in S-26-Promil-Gold™ (cow's milk formula) and group 4 in a chicken-based formula (Siriraj Hospital, Mahidol University). The microhardness of the specimens was then measured again. Data were analyzed using a one-way ANOVA and paired t-test with a 95% confidence interval. After exposure to the formula, the mean VHN for each study group was significantly higher (paired t-test, p < 0.05) except for group 1 (p = 0.345). The mean VHN for the the Murrah™ buffalo milk formula, the chicken-based formula and the S-26-Promil-Gold™ formula group were not significantly different from each other (one-way ANOVA, p > 0.05). In conclusion, S-26-Promil-Gold™ follow-on cow milk formula, Murrah™ buffalo milk formula and the chicken-based formula all increased bovine enamel microhardness after soaking for 2 hours.

  10. Clinical and radiographic assessment of mineral trioxide aggregate and calcium hydroxide as apexification agents in traumatized young permanent anterior teeth: A comparative study

    PubMed Central

    Damle, S. G.; Bhattal, Hiteshwar; Damle, Dhanashree; Dhindsa, Abhishek; Loomba, Ashish; Singla, Sumit

    2016-01-01

    Background: To evaluate and compare the efficacy of mineral trioxide aggregate (MTA) and traditionally used calcium hydroxide (Ca(OH)2) in inducing root end formation of immature roots of traumatized young permanent anterior teeth. Materials and Methods: The study was carried out on 22 nonvital, immature permanent maxillary incisors. Samples were allotted into two groups - Group I MTA and Group II Ca(OH)2 Success rate was determined based upon the time duration required for apical barrier formation. The canals were obturated using gutta-percha points in MTA group, after 24 h, whereas in Ca(OH)2 group, obturation was carried out after radiographic confirmation of the apical barrier. The clinical and radiographic evaluation was carried out at a follow-up periods of 3, 6, and 9 months and statistical analysis was carried out by SPSS version 15.0 statistical analysis software (Chi-square test and fisher exact test). Results: In MTA Group, barrier formation was observed in 90.90% of the patients after 9 months whereas in Ca(OH)2 Group, the same was observed in 81.81%. The mean time required for barrier formation in MTA group was 4.90 months and 5.33 months in Ca(OH)2 group. Conclusion: MTA and Ca(OH)2, as medicaments for apexification, were comparable in terms of the evaluation parameters. However, MTA was beneficial in terms of immediate obturation of immature roots with wide open apices. PMID:27274351

  11. Comparative Study of the Shear Bond Strength of Flowable Composite in Permanent Teeth Treated with Conventional Bur and Contact or Non-Contact Er:YAG Laser

    PubMed Central

    Parhami, Parisa; Pourhashemi, Seyed Jalal; Ghandehari, Mehdi; Mighani, Ghasem; Chiniforush, Nasim

    2014-01-01

    Introduction: The aim of this study was to evaluate and compare the in vitro effect of the Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser with different radiation distances and high-speed rotary treatment on the shear bond strength of flowable composite to enamel of human permanent posterior teeth. Methods: freshly extracted human molar teeth with no caries or other surface defects were used in this study (n=45). The teeth were randomly divided into 3 groups. Group 1: treated with non-contact Er:YAG Laser and etched with Er:YAG laser, Group 2: treated with contact Er:YAG Laser and etched with Er:YAG laser, Group 3 (control): treated with diamond fissure bur and etched with acid phosphoric 37%. Then the adhesive was applied on the surafces of the teeth and polymerized using a curing light appliance. Resin cylinders were fabricated from flowable composite. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. Results: The amount of Shear Bond Strength (SBS) in the 3 treatment groups was not the same (P<0.05).The group in which enamel surfaces were treated with diamond fissure bur and etched with acid (conrtol group) had the highest mean shear bond strength (19.92±4.76) and the group in which the enamel surfaces were treated with contact Er:YAG laser and etched with Er:YAG laser had the lowest mean shear bond strength (10.89±2.89). Mann-whitney test with adjusted P-value detected significant difference in shear bond strength between the control group and the other 2 groups (P < 0.05). Conclusion: It was concluded that both contact and non-contact Er:YAG laser treatment reduced shear bond strength of flowable resin composite to enamel in comparison with conventional treatment with high speed rotary. Different Er:YAG laser distance irradiations did not influence the shear bond strength of flowable composite to enamel. PMID:25653813

  12. 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.

  13. Differential Neuronal Plasticity of Dental Pulp Stem Cells From Exfoliated Deciduous and Permanent Teeth Towards Dopaminergic Neurons.

    PubMed

    Majumdar, Debanjana; Kanafi, Mohammad; Bhonde, Ramesh; Gupta, Pawan; Datta, Indrani

    2016-09-01

    Based on early occurrence in chronological age, stem-cells from human exfoliated deciduous teeth (SHED) has been reported to possess better differentiation-potential toward certain cell-lineage in comparison to stem-cells from adult teeth (DPSCs). Whether this same property between them extends for the yield of functional central nervous system neurons is still not evaluated. Hence, we aim to assess the neuronal plasticity of SHED in comparison to DPSCs toward dopaminergic-neurons and further, if the difference is reflected in a differential expression of sonic-hedgehog (SHH)-receptors and basal-expressions of tyrosine-hydroxylase [TH; through cAMP levels]. Human SHED and DPSCs were exposed to midbrain-cues [SHH, fibroblast growth-factor8, and basic fibroblast growth-factor], and their molecular, immunophenotypical, and functional characterization was performed at different time-points of induction. Though SHED and DPSCs spontaneously expressed early-neuronal and neural-crest marker in their naïve state, only SHED expressed a high basal-expression of TH. The upregulation of dopaminergic transcription-factors Nurr1, Engrailed1, and Pitx3 was more pronounced in DPSCs. The yield of TH-expressing cells decreased from 49.8% to 32.16% in SHED while it increased from 8.09% to 77.47% in DPSCs. Dopamine release and intracellular-Ca(2+) influx upon stimulation (KCl and ATP) was higher in induced DPSCs. Significantly lower-expression of SHH-receptors was noted in naïve SHED than DPSCs, which may explain the differential neuronal plasticity. In addition, unlike DPSCs, SHED showed a down-regulation of cyclic adenosine-monophosphate (cAMP) upon exposure to SHH; possibly another contributor to the lesser differentiation-potential. Our data clearly demonstrates for the first time that DPSCs possess superior neuronal plasticity toward dopaminergic-neurons than SHED; influenced by higher SHH-receptor and lower basal TH expression. J. Cell. Physiol. 231: 2048-2063, 2016. © 2016

  14. Efficacy of Biodentine as an Apical Plug in Nonvital Permanent Teeth with Open Apices: An In Vitro Study

    PubMed Central

    Bani, Mehmet; Sungurtekin-Ekçi, Elif; Odabaş, Mesut Enes

    2015-01-01

    The aim of this study was to evaluate the apical microleakage of Biodentine and MTA orthograde apical plugs and to compare the effect of thickness of these biomaterials on their sealing ability. A total of eighty maxillary anterior teeth were used. The apices were removed by cutting with a diamond disc (Jota, Germany) 2 mm from the apical root end in an attempt to standardize the working length of all specimens to 15 ± 1 mm. Both materials were placed in 1–4 mm thickness as apical plugs root canal. Root canal leakage was evaluated by the fluid filtration technique. One-way ANOVA was used in order to determine normality of dispersal distribution of parameters; thereafter, results were analyzed by Kolmogorov-Smirnov test. Overall, between microleakage values of MTA and Biodentine regardless of apical plug thickness, no difference was observed. In terms of plug thickness, a statistically significant difference was observed between the subgroups of MTA and Biodentine (p < 0.05). The apical sealing ability of Biodentine was comparable to MTA at any apical plug thickness. PMID:26436090

  15. Effects of the diamond grit sizes of the commercial dental diamond points on the weight-load cutting of bovine enamel and glass-ceramic Typodont teeth.

    PubMed

    Taira, M; Wakasa, K; Yamaki, M; Matsui, A

    1990-12-01

    To evaluate the effect of the diamond grit size of commercial dental diamond points on the dental cutting, we conducted weight-load cutting tests on bovine enamel and glass-ceramic typodont teeth using 3 different diamond grit sizes and air-bearing and ball-bearing air-turbine driven handpieces. With the transverse load applied on the diamond point varied between 20 and 80 g, we measured rotational cutting speed and cutting volume. Generally, increases in applied load caused decreases in rotational cutting speed and increases in cutting volume. The intensity of this trend, however, differed between grit sizes. Regular grit diamond points most strongly showed this tendency, while super-fine grit diamond points were least affected. Fine grit diamond points behaved in a manner similar to regular grit points.

  16. Caries-Preventive Effect of High-Viscosity Glass Ionomer and Resin-Based Fissure Sealants on Permanent Teeth: A Systematic Review of Clinical Trials

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2016-01-01

    Background Glass-ionomers are traditionally regarded to be inferior to resin as fissure sealants in protecting teeth from dental caries, due to their comparatively lower retention rate. Unlike low-viscosity glass-ionomers, high-viscosity glass-ionomer cements (HVGIC) are placed as sealants by pressing the material into pits and fissures with a petroleum-jelly-coated index finger. Hence, HVGIC sealants are assumed to penetrate pits and fissures deeper, resulting in a higher material retention rate, which may increase its caries-preventive effect. Methods The aim of this review was to answer the question as to whether, in patients with fully erupted permanent molar teeth, HVGIC based fissure sealants are less effective to protect against dental carious lesions in occlusal pits and fissures than resin-based fissure sealants? A systematic literature search in eight databases was conducted. Heterogeneity of accepted trials and imprecision of the established evidence were assessed. Extracted sufficiently homogenous datasets were pooled by use of a random-effects meta-analysis. Internal trial validity was evaluated. The protocol of this systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO / Nr.: CRD42015016007). Results Seven clinical trials were provisionally included for further review. Of these, one was excluded. Seven trial reports reporting on six trials were accepted. From these, 11 datasets were extracted and pooled in four meta-analyses. The results suggest no statistically significant differences after up to 48 months and borderline significant differences in favour of HVGIC sealants after 60 months (RR 0.29; 95% CI: 0.09–0.95; p = 0.04 / RD -0.07; 95% CI: -0.14, -0.01). The point estimates and upper confidence levels after 24, 36, 48 and 60 months of RR 1.36; RR 0.90; RR 0.62; RR 0.29 and 2.78; 1.67; 1.21; 0.95, respectively, further suggest a chronological trend in favour of HVGIC above resin

  17. New teeth from old: treatment options for retained primary teeth.

    PubMed

    Robinson, S; Chan, M F W-Y

    2009-10-10

    Retention of primary teeth beyond their expected exfoliation date is encountered relatively frequently. Most commonly this is due to absence of the permanent successor. In this article patient assessment and the restorative treatment options are discussed with particular emphasis on retention of the primary tooth/teeth in the medium to long-term. The restorative techniques that may be used to improve aesthetics and function of retained primary teeth are illustrated. Consideration of this minimally invasive approach is commended in such cases.

  18. Facial and dental injuries due to dog bite in a 15-month-old child with sequelae in permanent teeth: a case report.

    PubMed

    Cunha, Robson Frederico; Delbem, Alberto Carlos Botazzo; Correia, Adriana Sales Cunha; Novais, Renata Zoccal

    2008-12-01

    This article reports a longitudinal follow-up of a 15-month-old child with dental trauma resulting from an attack by a dog. The injury consisted of laceration of the facial tissues and loss of the upper central deciduous incisors, in addition to loss of bone tissue in the same area. A malformation of the crown of the right central permanent incisor and complete change of the shape of the left central permanent incisor were observed. The etiological factors of childhood injuries as well as the importance of dental emergency care are discussed and the 14-year clinical and radiographic follow up of the case is presented.

  19. Bovine dentine organic matrix down-regulates osteoclast activity.

    PubMed

    Sriarj, Wantida; Aoki, Kazuhiro; Ohya, Keiichi; Takagi, Yuzo; Shimokawa, Hitoyata

    2009-01-01

    Physiological root resorption is a phenomenon that normally takes place in deciduous teeth; root resorption of permanent teeth occurs only under pathological conditions. The molecular mechanisms underlying these processes are still unclear. Our previous study showed that osteoclasts cultured on deciduous dentine exhibited a higher degree of resorption and higher levels of cathepsin K and MMP-9 mRNA than osteoclasts cultured on permanent dentine. These results could be because of different susceptibilities to acid and the different organic matrices between deciduous and permanent dentine. Thus, the purpose of this study was to investigate the effect of dentine extracts from bovine deciduous and permanent dentine on osteoclast activity. Osteoclasts, obtained from mouse bone marrow cells co-cultured with an osteoblast-rich fraction in the presence of 1,25-(OH)(2)-vitamin D3 and PGE2, were incubated with or without 0.6 M HCl extracts from bovine deciduous or permanent dentine for 48 h. TRAP positive cell number, TRAP activity, the areas of resorption pits, and mRNA levels of TRAP, v-ATPase, calcitonin receptor, cathepsin K, and MMP-9 were examined. The results illustrated that TRAP activity, the resorbed area, and the mRNA levels of osteoclast marker genes seemed to be suppressed by both deciduous and permanent dentine extracts. These findings indicate that some factors that suppress osteoclast activity are contained in both deciduous and permanent dentine extracts. Although there was no significant difference in osteoclast activity between deciduous and permanent dentine extracts, osteoclasts incubated with permanent dentine extracts tend to exhibit less resorption activity than those incubated with deciduous dentine extracts. However, we could not clearly explain the causes of this.

  20. A practice-based study on stepwise excavation of deep carious lesions in permanent teeth: a 1-year follow-up study.

    PubMed

    Bjørndal, L; Thylstrup, A

    1998-04-01

    This study reports results from a practice-based study in which deep carious lesions were treated by general dental practitioners using stepwise excavation. The material comprised 94 teeth with deep carious lesions which the clinicians considered would result in pulp perforation if treated by a single and terminal excavation. At the first visit excavation of the peripheral dentine was completed. The outermost part of the central and necrotic dentine was gently removed with a sharp excavator. Standardized assessments of the dentine colour and consistency were made before application of a calcium hydroxide-containing base material and temporary filling. The final excavation was completed after a treatment interval ranging from 2 to 19 months, with a median of 6 months. Reassessments of the dentine colour and consistency were made before complete removal of demineralized dentine. The central dentine was significantly browner and less softened after the sealing period. After removal of the dark-brownish dentine during the final excavation, the colour and consistency of the exposed central dentine was found to resemble that of the completely excavated peripheral dentine. Only five cases resulted in pulp perforation during the final excavation. The high success rate of teeth surviving the final treatment without pulp exposure after 1 year of observation shows that it was possible for dentists in general practice to administer and manage the treatment of deep carious lesions, a process which may prolong tooth survival compared with conventional endodontic techniques.

  1. Endodontic management of nonvital permanent teeth having immature roots with one step apexification, using mineral trioxide aggregate apical plug and autogenous platelet-rich fibrin membrane as an internal matrix: Case series

    PubMed Central

    Sharma, Vivek; Sharma, Sarang; Dudeja, Pooja; Grover, Shibani

    2016-01-01

    A tooth with blunderbuss canal and open apex can be an endodontic challenge because of difficulty in obtaining an apical seal, and existing thin radicular walls which are susceptible to fracture. To overcome the limitations of traditional long-term calcium hydroxide apexification procedures, nonsurgical one step apexification using an array of materials such as mineral trioxide aggregate (MTA) has been suggested. However, adequate compaction of MTA in teeth with wide open apices can be an arduous task, and an internal matrix is required for controlled placement of MTA against which obturating material can be condensed. Platelet-rich fibrin (PRF), a second generation platelet concentrate containing several growth factors that promotes hard and soft-tissue healing, has been used as an internal matrix to create an apical plug of MTA and hence prevent extrusion of filling materials. This case series presents the endodontic management of immature permanent teeth with open apices using internal matrix of autologous PRF membrane and one step apical barrier placement of MTA. PMID:27041904

  2. Teething Tots

    MedlinePlus

    ... Your 1- to 3-Month-Old Feeding Your 4- to 7-Month-Old Feeding Your 8- to 12-Month-Old Feeding Your 1- to 2-Year-Old Teething ... en español La dentición en los niños Teething, the emergence of the first teeth through ...

  3. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    PubMed Central

    Agrawal, Nikita; Shashikiran, N. D.; Singla, Shilpy; Ravi, K. S.; Kulkarni, Vinaya Kumar

    2014-01-01

    Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks. PMID:24808700

  4. Interrelationships in the Variability of Root Canal Anatomy among the Permanent Teeth: A Full-Mouth Approach by Cone-Beam CT

    PubMed Central

    Peters, Ove A.; Maury, Elisabeth; Telmon, Norbert; Georgelin-Gurgel, Marie; Maret, Delphine

    2016-01-01

    Objectives In endodontic practice, clinicians should be aware of possible root canal anatomic variations. The aim of this study was to assess using CBCT acquisitions regarding whether one root canal anatomy of a tooth is associated with a specific anatomy of another tooth. Methods A total of 106 CBCT acquisitions were obtained using a CBCT scanner with 200μm voxel size. Numbers of roots and canals of the entire dentition were described. Bivariate analyses and logistic regressions were conducted to explore root canal anatomy on one tooth according to age, gender, jaw, side and the others teeth. Multiple correspondence analysis (MCA) was performed to correlate the different numbers of canals profiles. Results A total of 2424 teeth were analyzed. Independently from the other variables, the presence of an additional root canal on a mandibular incisor increases the risk of having an additional root canal on a mandibular premolar (OR [95%] 3.7 [1.0;13.2]). The mandibular molar variability increases in women compared to men (OR [95%] 0.4 [0.1; 0.9]). MCA showed correspondence between 2-canals maxillary incisor and canines and 5-canals maxillary molars, and some correlation between additional canal on maxillary and mandibular premolars. Conclusions Although CBCT examinations are conducted in the first intention of making a diagnosis or prognostic evaluation, medium FOV acquisitions could be used as an initial database thus furnishing preliminary evaluations and information. In endodontic practice, clinicians should be aware of possible root canal anatomic variations. The visualization of all canals is considered essential in endodontic therapy. The use of multi-correspondence analysis for statistics in endodontic research is a new approach as a prognostic tool. PMID:27764246

  5. Orthodontic movement in deciduous teeth

    PubMed Central

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption? PMID:25992982

  6. Orthodontic movement in deciduous teeth.

    PubMed

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?

  7. Variations in the vestibular cortical bone of permanent canine teeth in orthodontic patients. a comparative study: linear tomography vs. cbct (3d accuitomo).

    PubMed

    Mateu, María E; Martínez, M E; Dagum, H; Benítez Rogé, Sandra C; Bruno, Gabriela I; Hecht, Pedro; Folco, Alejandra A

    2014-01-01

    The aim of this study was to compare the results of measuring the height of the vestibular cortical bone of canine teeth by linear tomography (LT) and 3-D Accuitomo cone beam computed tomography (CBCT) before and after aligning dental arches by orthodontic treatment. LT and CBCT were performed before and after orthodontic alignment on 12 canines in three patients undergoing orthodontic treatment, and the height of the canine vestibular cortical bones measured in mm. Measurements were taken by double-blinded operators. The mean variation in height of the vestibular cortical bone with orthodontic treatment was - 0,33 mm} 0.233 standard error using CBCT and -0,08mm } 0.55 standard error using LT. Analysis of variance (ANOVA) was performed to compare the techniques, the patients and upper and lower canines. No significant difference was found for any of the cases. Using LT to evaluate vestibular crest cortical bone in canines is comparable in efficiency to using CBCT. Height in millimeters is less in LT because image resolution is lower and when it is very thin it is not appreciable by this method.

  8. PREFORMED METAL CROWNS FOR THE PERMANENT DENTITION.

    PubMed

    Millar, Lynsey M; Cairns, Alison M; Fowler, Lauren

    2015-11-01

    Preformed metal crowns have a range of uses in paediatric dentistry in both the primary and permanent dentition. This article provides an overview of their use in permanent teeth, including teeth that have been affected by molar incisor hypomineralisation, caries, developmental defects and tooth surface loss. The indications for use are described, along with the clinical technique for placement

  9. Teething Tots

    MedlinePlus

    ... the first set of teeth will fall out, tooth decay makes them fall out more quickly, leaving gaps ... brush and floss. Another important tip for preventing tooth decay: Don't let your baby fall asleep with ...

  10. Your Teeth

    MedlinePlus

    ... used by people millions of years ago when humans had larger jaws and ate food that needed a lot of chewing. It's believed that they're called wisdom teeth because they come in later in life, when ...

  11. 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.

  12. Oxalic acid in saliva, teeth and tooth tartar.

    PubMed

    Wahl, R; Kallee, E

    1994-11-01

    Oxalic acid was determined in human saliva, teeth, tartar, and in animal teeth. Saliva from dentally healthy male subjects contained 0.10 +/- 0.09 mmol/l (n = 41) and those of dentally healthy female subjects 0.18 +/- 0.17 mmol/l (n = 40). Oxalic acid in tartar from 16 patients was 3.3 +/- 1.2 mmol/kg tartar. In human teeth, oxalic acid was 1.0 +/- 0.3 mmol/kg in milk teeth (n = 12) and 0.9 +/- 0.6 mmol/kg in permanent teeth (n = 60). Human teeth were sorted into age groups and into molars, incisors and premolars. In animal teeth, oxalic acid content varied widely. The formed calcium oxalate is proposed to be a 'physiological' protective mechanism for teeth.

  13. Preservation of Involved Teeth Associated with Large Dentigerous Cysts

    PubMed Central

    Guven, Yeliz; Kasimoglu, Yelda; Soluk Tekkesin, Merva; Ulug, Dicle; Cankaya, Abdulkadir Burak; Tuna, Elif Bahar; Gencay, Koray; Aktoren, Oya

    2014-01-01

    Dentigerous cysts (DCs) are benign odontogenic cysts that are associated with the crowns of permanent teeth. The purpose of this study is to describe the management of DCs in four children. Four boys aged between 7 and 9 years were referred to our clinics with the complaints of intraoral alveolar swelling or facial asymmetry on the affected area. The panoramic radiographies showed large, well-defined radiolucent lesions associated with the deciduous teeth and displaced tooth buds. The treatment consisted of the extraction of the involved deciduous tooth and marsupialization of the cyst to allow eruption of the permanent tooth. Permanent teeth displaced by the DCs in three cases erupted spontaneously within one-year period. The case with horizontally displaced permanent tooth was managed by replantation. This is the first time that underlying permanent tooth in a DC case was intentionally replanted. PMID:27355026

  14. Late Developing Supernumeraries in a Case of Nonsyndromic Multiple Supernumerary Teeth

    PubMed Central

    Bozkurt, Mine; Tüzüner Öncül, Ayşegül; Göçer, Rukiye; Sarı, Şaziye

    2015-01-01

    Objective. This case report presents 3-year follow-up of a case of nonsyndromic multiple supernumerary teeth (NSMST) with 11 supernumerary teeth, 2 of which showed subsequent formation. Case Report. A 10-year-old girl was referred to the dental clinic with the chief complaint of delayed eruption. Radiographic examination showed 9 retained supernumerary teeth. The treatment plan consisted of extraction of the supernumerary teeth and associated primary teeth in order to allow the permanent teeth to erupt. After 2 years of follow-up, 2 additional supernumerary teeth were observed. Conclusion. Regular follow-up for late forming supernumeraries is crucial for NSMST cases. PMID:25649422

  15. An evaluation of factors associated with persistent primary teeth.

    PubMed

    Aktan, Ali Murat; Kara, Isa; Sener, Ismail; Bereket, Cihan; Celik, Salih; Kirtay, Mustafa; Ciftçi, Mehmet Ertugrul; Arici, Nursel

    2012-04-01

    The aim of the present study was to investigate the reasons for the persistence of primary teeth and also use panoramic radiography to determine the characteristics of persistence teeth. Four-hundred and twenty-six panoramic radiographies, which diagnosed one or more retained primary teeth, were selected from 100,577 panoramic radiographic image files from nine clinics and six different cities in Turkey. The selected radiographies were evaluated to determine the reasons for the persistence of primary teeth; furthermore, this study analyzed the characteristics of the retained primary teeth including tooth type, number, location, and root resorption, and whether, or not, the primary teeth showed evidence of pathological conditions, such as periodontal problems, caries, ankylosis, infra-occlusions, or tipping of the adjacent permanent teeth. Six hundred and seventy-seven retained primary teeth were determined in 426 patients (148 males and 278 females). Retained primary teeth were found most frequently in the mandible rather than the maxilla and the left side was more frequently affected than the right side. Level 1 was found as a most frequently encountered root resorption level. Within the limitation of the present study, the most common type of persistent primary teeth seen on the dental arch were mandibular primary second molars, followed by maxillary primary canines. The most frequent reason for the persistence was the congenital absence of successors to the primary teeth, followed by impaction of the successor teeth.

  16. Strontium in 19th century Australian children's teeth

    NASA Astrophysics Data System (ADS)

    Williams, A.-M. M.; Donlon, D. A.; Bennett, C. M.; Siegele, R.

    2002-05-01

    The enamel of teeth from 57 children, who died in the mid to late 1800s, were analysed to investigate strontium (Sr) concentrations in historic teeth. Teeth were analysed using proton induced X-ray emission at the Australian Nuclear Science and Technology Organisation (ANSTO). Where available, multiple teeth were analysed for each individual including permanent (molars and premolars) and deciduous teeth (molars). Preliminary results show that Sr does not appear to be affected by the postmortem environment. Sr levels in permanent molars strongly correlate with levels in the premolars but not with the deciduous molars. Concerns are raised over the large variation seen in Sr levels and the effect it would have on the interpretation of Sr levels in studies with small sample sizes.

  17. Factors influencing trace element composition in human teeth

    SciTech Connect

    Tandon, L.; Iyengar, G.V.

    1997-12-01

    The authors recently compiled and reviewed the literature published in or after 1978 for 45 major, minor, and trace elements in human teeth as a part of an International Atomic Energy Agency (IAEA) study. The purpose of this paper is to discuss the various factors that influence the concentration levels of certain trace elements in human teeth. The sampling practices and analytical techniques that are applicable for trace element analysis are also discussed. It is also our intention to identify reference range of values, where data permit such conclusions. The scrutiny was designed to identify only the healthy permanent teeth, and values from teeth with fillings, caries, or periodontal diseases were eliminated.

  18. Impacted Wisdom Teeth

    MedlinePlus

    ... Wisdom%20teeth&alt=sh. Accessed March 9, 2015. Toothache and infection. The Merck Manual Professional Edition. http:// ... dental_disorders/symptoms_of_dental_and_oral_disorders/toothache_and_infection.html?qt=Wisdom%20teeth&alt=sh. ...

  19. Brushing Your Child's Teeth

    MedlinePlus

    ... gov/ency/patientinstructions/000769.htm Brushing Your Child’s Teeth To use the sharing features on this page, ... how to brush their teeth on their own. Tooth and Gum Care for Young Children You should ...

  20. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth

    PubMed Central

    Ata-Ali, Fadi; Peñarrocha-Oltra, David; Peñarrocha-Diago, Miguel

    2014-01-01

    The aim of this article was to review the literature on supernumerary teeth, analyzing their prevalence, etiology, diagnosis, treatment and possible complications. An electronic search was made in the Pubmed-Medline database up to January 2014 using the key search terms “multiple supernumerary teeth” (n=279), “prevalence supernumerary teeth” (n=361), and “supernumerary teeth” (n=2412). In addition to the articles initially identified, others were included in the review proceeding from a manual search and from any references considered of relevance. Supernumerary teeth are those that exceed the normal dental formula. They are more common in men, more common in the upper maxilla, and more prevalent in permanent dentition. Complications associated with supernumerary teeth include dental impaction, delayed eruption, ectopic eruption, overcrowding, spacing anomalies and the formation of follicular cysts. The treatment of supernumerary teeth depends on their type, position, and possible complications, detected clinically and radiographically. No clear consensus exists as to the best time to extract unerupted supernumerary teeth. Key words:Hyperdoncia, supernumerary teeth, impacted teeth, treatment, permanent teeth, deciduous teeth. PMID:25593666

  1. Malocclusion (Misaligned Teeth)

    MedlinePlus

    ... misaligned. People who habitually suck their thumb or push their tongue up against their front teeth may cause the upper ... bands that apply force to slowly and gradually pull teeth into proper ... slightly ground down or built up so they meet better. After the teeth are ...

  2. Replacement of hopeless retained primary teeth by immediate dental implants: a case report.

    PubMed

    de Oliveira, Rafael R; Macedo, Guilherme O; Muglia, Valdir A; Souza, Sérgio L S; Novaes, Arthur B; Taba, Mário

    2009-01-01

    Hopeless retained primary teeth without permanent successors represent a restorative challenge for clinicians, along with esthetic and functional problems for patients. While various treatment approaches for congenitally missing teeth have been proposed, the replacement of a missing tooth with a dental implant offers specific advantages, such as preservation of the alveolar crest and elimination of the need to restore the adjacent teeth, over other options for tooth replacement. The aim of this article was to illustrate the surgical and prosthetic treatment with implants of a patient with primary teeth without permanent successors.

  3. Natal teeth: a review.

    PubMed Central

    Leung, Alexander K. C.; Robson, William Lane M.

    2006-01-01

    The incidence of natal teeth is approximately 1:2,000 to 1:3,000 live births. The most commonly affected teeth are the lower primary central incisors. Natal teeth usually occur in pairs. The eruption of more than two natal teeth is rare. The majority of natal teeth represent the early eruption of normal primary deciduous dentition. Less than 10% of natal teeth are supernumerary. Natal teeth might resemble normal primary dentition in size and shape; however, the teeth are often smaller, conical and yellowish, and have hypoplastic enamel and dentin with poor or absent root formation. Complications include discomfort during suckling, sublingual ulceration, laceration of the mother's breasts and aspiration of the teeth. A dental roentgenogram is indicated to differentiate the premature eruption of a primary tooth from a supernumerary tooth. Tooth extraction is indicated if the tooth is supernumerary or excessively mobile. If the tooth does not interfere with breastfeeding and is otherwise asymptomatic, no treatment is necessary. Images Figure 1 PMID:16708508

  4. A Novel Technique in Restoring Fractured Anterior Teeth

    PubMed Central

    K, Rajavardhan; Sankar, A.J. Sai; Shaik, Tanveer Ahmed; V, Naveen Kumar; K, Raj Kumar

    2014-01-01

    Trauma to the anterior teeth is a common phenomenon in young children and in adolescents. Uncomplicated crown fracture to the permanent teeth has an intense effect not only on the patient’s appearance, but also on function and speech. This case report describes a novel technique in restoring an uncomplicated fractured maxillary anterior tooth in a young patient with direct composite, which is economical and requires less chair side time. PMID:24701546

  5. Physiologic root resorption in primary teeth: molecular and histological events.

    PubMed

    Harokopakis-Hajishengallis, Evlambia

    2007-03-01

    Root resorption is a physiologic event for the primary teeth. It is still unclear whether odontoclasts, the cells which resorb the dental hard tissue, are different from the osteoclasts, the cells that resorb bone. Root resorption seems to be initiated and regulated by the stellate reticulum and the dental follicle of the underlying permanent tooth via the secretion of stimulatory molecules, i.e. cytokines and transcription factors. The primary root resorption process is regulated in a manner similar to bone remodeling, involving the same receptor ligand system known as RANK/RANKL (receptor activator of nuclear factor-kappa B/ RANK Ligand). Primary teeth without a permanent successor eventually exfoliate as well, but our current understanding on the underlying mechanism is slim. The literature is also vague on how resorption of the pulp and periodontal ligament of the primary teeth occurs. Knowledge on the mechanisms involved in the physiologic root resorption process may enable us to delay or even inhibit exfoliation of primary teeth in those cases that the permanent successor teeth are not present and thus preservation of the primary teeth is desirable.

  6. Is bovine dentine an appropriate substitute for human dentine in erosion/abrasion tests?

    PubMed

    Wegehaupt, F; Gries, D; Wiegand, A; Attin, T

    2008-05-01

    The study aimed to compare the dentine wear of primary and permanent human and bovine teeth because of erosion/abrasion and evaluate if bovine dentine is an appropriate substitute for human dentine in further erosion/abrasions tests. Dentine samples from deciduous molars and human third molars as well as from calves' and cattle's lower incisors were prepared and baseline surface profiles were recorded. Each day all samples were demineralized in 1% citric acid, tooth brushed with 100 brushing strokes with toothpaste slurry and stored in artificial saliva for the rest of the day. This cycle was run for 20 days. Afterwards, new surface profiles were recorded and dentine wear was calculated by a customized computer program. Dentine wear because of erosion/abrasion was not statistically, significantly different for human third molars and cattle's lower incisors (P = 0.7002). The dentine wear because of erosion/abrasion of deciduous molars and calves' lower incisors was significantly different (P < 0.0000). No statistically significant difference in the dentine wear of human third molars and cattle's lower incisors was observed, so that the use of cattle's lower incisors as substitute for adult human teeth for further investigations in erosion/abrasion studies could be accepted.

  7. A multi-disciplinary approach to congenitally missing anterior teeth.

    PubMed

    Galler, David; Quiong, Caroline; Galler, Jeffrey

    2009-01-01

    Congenitally missing teeth are not an unusual occurrence. What makes this case study unique is the combination of restorative challenges offered. The patient presented with the permanent upper right cuspid and lower anterior right and left central incisors congenitally missing, and with an underdeveloped upper right lateral incisor. Distinctive existing occlusion and tooth alignment difficulties precluded a simple approach of merely extracting the residual primary teeth and replacing the missing teeth prosthetically. Using orthodontics to create ideal interocclusal and interarch space was critical in preparing this case for prosthetic restoration.

  8. Treatment of avulsed teeth with Emdogain--a case report.

    PubMed

    Caglar, Esber; Tanboga, Ilknur; Süsal, Seckin

    2005-02-01

    The present case report describes the reimplantation of avulsed teeth with the treatment of Emdogain. Case was avulsed right maxillary permanent central and lateral incisor in a 9-year-old girl suffering from a traumatic injury. After pretreatment of avulsed teeth, Emdogain was applied to the root surface and into the extraction socket with subsequent replantation of the tooth. Evaluation parameters included horizontal and vertical percussion sound and periapical radiographs. At 1-2-6-12-month follow-up period, the clinical and radiographic appearance of the teeth showed resolution of mobility and no signs of replacement resorbption.

  9. Mouth and Teeth (For Parents)

    MedlinePlus

    ... system , but it does much more than get digestion started. The mouth — especially the teeth, lips, and ... Mouth and Teeth Do The first step of digestion involves the mouth and teeth. Food enters the ...

  10. Report of a case with 19 supernumerary teeth in a non-syndromic patient

    PubMed Central

    Yan, Lei; Yu, Long Wang; Bhandari, Kishor; Shan, Chang Li

    2014-01-01

    Supernumerary teeth occur frequently in human dentition, but presence of multiple supernumerary teeth in patients without any associated syndrome or systemic disorder is a rare phenomenon. Presence of supernumerary teeth in itself is not a problem and may not require removal in all cases but in certain conditions, they may be associated with several clinical complications and require removal. Here, we present a 14 year old female who complained of non emergence of permanent teeth. Orthopantomogram initially showed presence of fifteen impacted supernumerary teeth distributed in all quadrants, but later, cone-beam computed tomography further revealed four additional teeth, totaling to nineteen supernumerary teeth. Consultation with concerned specialists ruled out any syndromes or systemic disorders which led us to the diagnosis of “non-syndromic multiple supernumerary teeth” and this probably is the highest number of supernumerary teeth reported in a single non-syndromic patient till date. PMID:25565732

  11. Sequential Supernumerary Teeth Development in a Non-Syndromic Patient; Report of a Rare Case

    PubMed Central

    Jafarian, Mohammad; Nazemi, Bahareh; Bargrizan, Majid; Ramezani, Jamileh; Ansari, Ghassem

    2013-01-01

    Isolated impacted supernumerary teeth are quite rare, but they can be seen associated with several syndromes such as cleidocranial dysostosis or Gardner’s syndrome. This article aims to discuss a case of sequential formation of supernumerary teeth with no other associated disease or syndrome. A 17-year-old Iranian male with 8 impacted supernumerary teeth was referred to the department of pediatric dental clinic at Shahid Beheshti Medical University in Tehran with a history of several impacted unerupted teeth. Repeated and periodical clinical and radiographic examinations revealed newly formed teeth buds in unusual dental ages. All extra teeth were associated with generalized enamel hypoplasia to some degree on their relative permanent adjacent teeth. The patient did not have any record of a systemic disease or any syndromic condition to relate his dental problem to. This rare condition involved repeated and continued formation of extra teeth out of the normal numbers and dental age evident in serial radiographs. PMID:24910667

  12. [The cervical third of deciduous teeth. An ultrastructural study of the heard tissues by SEM].

    PubMed

    Leonardi, R; Loreto, C; Caltabiano, R; Caltabiano, C

    1996-03-01

    As information on amelocemental junction of deciduous teeth is limited, this topographical area was investigated by scanning electron microscopy (SEM) to verify differences from that of permanent teeth. Twenty-six carious and non-carious human maxillary and mandibular primary teeth were placed in a fixative immediately after extraction. Pulpal tissue was removed from the pulpal chambers and root. The primary teeth blocked onto stubs and all specimens were platinum coated and examined by SEM. In these specimens an overlapping of cementum onto to enamel and an edge to edge relationship was dominant. No gaps between enamel and cementum were observed. The amelocemental junction of deciduous teeth seem to differ to that described for permanent teeth.

  13. Dental fluorosis prevalence and severity using Dean's index based on six teeth and on 28 teeth.

    PubMed

    Medina-Solis, Carlo Eduardo; Pontigo-Loyola, América Patricia; Maupome, Gerardo; Lamadrid-Figueroa, Hector; Loyola-Rodríguez, Juan Pablo; Hernández-Romano, Jesús; Villalobos-Rodelo, Juan José; de Lourdes Marquez-Corona, Ma

    2008-09-01

    To contrast the sensitivity, specificity, and positive-negative predictive values between dental fluorosis prevalence scored on 28 (DF28) and on six permanent teeth (DF6), we undertook a cross-sectional study on 1,538 adolescents (12 and 15 years old) residing in Hidalgo State, Mexico, a naturally fluoridated (>0.7 ppm) area at an elevated altitude (>2,500 m above sea level). Dental fluorosis was scored using Deans modified index. Using the scores obtained for all teeth present (DF28) as a gold standard, we calculated the sensitivity, specificity, positive-negative predictive values, and receiver operating characteristic and concordance index pertaining to the scores based on six teeth (upper incisors and canines). DF28 fluorosis prevalence was 81.7%; based on DF6, it was 58.7% (23% difference). Among 12 year olds, the difference between DF28 and DF6 was 20.1% (84.5 vs. 64.4%); among 15 year olds, it was 25.4% (79.4 vs. 54%). Among girls, it was 23.2% (81.1 vs. 57.9%) and among boys, 22.8% (82.2 vs. 59.4%). The fluorosis community indices were 1.75 (DF28) and 1.11 (DF6). All positive predictive values reached 100% while negative predictive values were below 45%. Concordance between DF28 and DF6 was 53.9%, and kappa coefficient was 0.40. Partial scoring of fluorosis based on esthetically important permanent teeth underestimated prevalence, compared to full-mouth scoring. The decision to use an abridged Dean's index protocol must take into account the number of teeth examined, and which specific teeth are examined, to appraise the benefit of reduced data collection effort against possible information loss.

  14. Bruxism (Teeth Grinding)

    MedlinePlus

    ... anger, frustration or tension Aggressive, competitive or hyperactive personality type Abnormal alignment of upper and lower teeth ( ... it usually goes away by the teen years. Personality type. Having a personality type that is aggressive, ...

  15. Teeth Injuries (For Parents)

    MedlinePlus

    ... Lessons? Visit KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding Your 1- to 3-Month-Old Feeding Your 4- to 7-Month-Old Feeding Your 8- to 12-Month-Old Feeding Your 1- to 2-Year-Old First Aid: Teeth Injuries ... Parents > First Aid: Teeth Injuries Print A A A ...

  16. Genetic influences on dental enamel that impact caries differ between the primary and permanent dentitions

    PubMed Central

    Bayram, Merve; Deeley, Kathleen; Reis, Maria Fernanda; Trombetta, Vanessa M.; Ruff, Timothy D.; Sencak, Regina C.; Hummel, Michael; Dizak, Piper M.; Washam, Kelly; Romanos, Helena F.; Lips, Helena F.; Alves, Gutemberg; Costa, Marcelo C.; Granjeiro, José M.; Antunes, Leonardo S.; Küchler, Erika C.; Seymen, Figen; Vieira, Alexandre R.

    2015-01-01

    Clinically, primary and permanent teeth are distinct anatomically and the presentation of caries lesions differs between the two dentitions. However, the possibility exists that genetic contributions to tooth formation of the two dentitions are different. The purpose of this study was to test the hypothesis that genetic associations with an artificial caries model will not be the same between primary and permanent dentitions. Enamel samples from primary and permanent teeth were tested for microhardness at baseline, after carious lesion creation, and after fluoride application to verify association with genetic variants of selected genes. Associations were found between genetic variants of ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, and matrix metalloproteinase 20 and enamel from permanent teeth but not with enamel from primary teeth. In conclusion, our data continue to support that genetic variation may impact enamel development and consequently individual caries susceptibility. These effects may be distinct between primary and permanent dentitions. PMID:26283008

  17. Molecular Analysis of the Caries Biofilm in Young Permanent Teeth

    DTIC Science & Technology

    2006-01-01

    iv V ita ............................................................................................. . . v L is t o f F ig u re s...1 1 A p p e n d ix: F ig u re s .............................................................................. 15 B ib lio g ra p h y...genetically different from the probiotic counterparts, and identify specific oral bacteria distributed on various tooth surfaces. Understanding the

  18. Delayed Replantation of Avulsed Teeth: Two Case Reports

    PubMed Central

    Savas, Selcuk; Kucukyilmaz, Ebru; Akcay, Merve; Koseoglu, Serhat

    2015-01-01

    This case report presents two cases of delayed replantation of avulsed maxillary central incisors after an extended dry extra-alveolar period. Eight-year-old boy and 10-year-old boy presented with avulsed maxillary central incisors due to trauma occurring 27 and 7 hours earlier, respectively. Treatment guidelines for avulsed mature/immature permanent teeth with prolonged extra-oral time were carried out for the teeth and the extra-oral endodontic treatment was completed. After having been repositioned, the teeth were stabilized for 4 weeks and prophylactic antibiotic was prescribed. Clinical and radiographic controls were done after 18 months for Case I and 12 months for Case II. During the follow-up periods the teeth reported in these cases have remained in a stable, functional position but revealed clinical initial replacement resorption and ankylosis. PMID:25810928

  19. Surface condition of primary teeth after approximal grinding and polishing.

    PubMed

    Jost-Brinkmann, P G; Otani, H; Nakata, M

    1991-01-01

    Mesiodistal reduction of primary teeth is necessary in cases with mild or moderate primary crowding, in patients treated with Fränkel appliance type I or II or in those who need to keep a primary molar as long as possible due to congenitally missing premolars. In order to minimize the risks of periodontal destruction and caries, the tooth surface should be polished after grinding. A technique for stripping permanent teeth, recently proven successful in achieving smoother enamel than untreated tooth surfaces, was slightly varied and applied to primary teeth. By means of scanning electron micrographs, it could be shown that application of this technique produces smooth surfaces on primary teeth as well. The procedure is described in detail and cases in which it should be used are presented.

  20. Age-Dependent Changes in Pb Concentration in Human Teeth.

    PubMed

    Fischer, Agnieszka; Wiechuła, Danuta

    2016-09-01

    The result of exposure to Pb is its accumulation in mineralized tissues. In human body, they constitute a reservoir of approx. 90 % of the Pb reserve. The conducted research aimed at determining the accumulation of Pb in calcified tissues of permanent teeth. The concentration of Pb in 390 samples of teeth taken from a selected group of Polish people was determined using the AAS method. Average concentration of Pb in teeth amounted to 14.3 ± 8.18 μg/g, range of changes: 2.21-54.8 μgPb/g. Accumulation of Pb in human body was determined based on changes in Pb concentration in teeth of subjects aged 13-84 years. It was found that in calcified tissues of teeth, the increase in concentration of Pb that occurs with age is a statistically significant process (p = 0.02, the ANOVA Kruskal-Wallis test). It was determined that the annual increase in concentration of Pb in tissues of teeth is approx. 0.1 μg/g. Moreover, a different course of changes in Pb concentration in tissues of teeth in people born in different years was observed. The level of Pb concentration in teeth of the oldest subjects (>60 years) decreased for those born in the 1930s compared to those in the 1950s. Teeth from younger persons (<60 years) were characterized by an increasing level of Pb concentration. The analysis of changes of Pb indicates that for low exposure, a relatively greater accumulation of Pb concentration in calcified tissues of teeth can occur.

  1. 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.

  2. Reasons for permanent tooth extractions in Taiwan.

    PubMed

    Lee, Chen-Yi; Chang, Yong-Yuan; Shieh, Tien-Yu; Chang, Chin-Shun

    2015-03-01

    There has been no study in Taiwan on reasons for extraction of permanent teeth. This study aimed to determine the reasons for permanent teeth extraction in Taiwan. This study performed a secondary data analysis based on the National Health Insurance Research Database. The 2009 database was adopted and there are 131 104 records of dental visits in the database; among them, 4958 visits (from 4811 patients) have a coding of extraction. The results showed that dental caries (55.3%) was the main reason for tooth extraction, followed by periodontal disease (22.1%). Extraction because of dental caries was commonly observed in all age-groups, and extractions because of periodontal disease increased in those older than 35 years. Maxillary and mandibular third molar were the most frequently removed tooth types, and most were extracted because of dental caries and impaction respectively.

  3. The post-mortem pink teeth phenomenon: a case report.

    PubMed

    Soriano, Evelyne-Pessoa; Carvalho, Marcus-Vitor-Diniz de; Santos, Francisco-Bernardo Dos; Mendoza, Clóvis-César de; Araújo, Maria-do Socorro-Dantas de; Campello, Reginaldo-Inojosa-Carneiro

    2009-07-01

    This study presents the case of the post-mortem pink teeth phenomenon observed during an autopsy procedure performed on the body of a man who was kidnapped and murdered approximately 30 days before the examination. The corpse was in an advanced stage of decomposition and putrefaction. Both maxillary and jaw bones were intact, as well as the permanent teeth which presented the "pink teeth phenomenon", probably due to a haemorrhage in the pulp chambers. The pink discolouration was most pronounced at the neck of the teeth. The cause of death was asphyxia. Although the examiners stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining the cause of death, the results of other studies have shown that the pink teeth phenomenon is a common finding related to cases of asphyxia such as strangulation, drowning or suffocation. Thus, the pink teeth phenomenon must be studied in order to determine its role as a post-mortem finding. As of now, an exact relationship between the cause of death and this phenomenon remains unknown.

  4. Essure Permanent Birth Control

    MedlinePlus

    ... and Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Essure System Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

  5. About Kids' Teeth

    MedlinePlus

    ... of your baby getting the bacteria that cause tooth decay. Make sure you take good care of your baby’s teeth – this reduces the number of bacteria in your baby’s mouth. Decay Prevention Tips Don’t share saliva with your baby ...

  6. Mercury Amalgam Diffusion in Human Teeth Probed Using Femtosecond LIBS.

    PubMed

    Bello, Liciane Toledo; da Ana, Patricia Aparecida; Santos, Dário; Krug, Francisco José; Zezell, Denise Maria; Vieira, Nilson Dias; Samad, Ricardo Elgul

    2017-01-01

    In this work the diffusion of mercury and other elements from amalgam tooth restorations through the surrounding dental tissue (dentin) was evaluated using femtosecond laser-induced breakdown spectroscopy (fs-LIBS). To achieve this, seven deciduous and eight permanent extracted human molar teeth with occlusal amalgam restorations were half-sectioned and analyzed using pulses from a femtosecond laser. The measurements were performed from the amalgam restoration along the amalgam/dentin interface to the apical direction. It was possible to observe the presence of metallic elements (silver, mercury, copper and tin) emission lines, as well as dental constituent ones, providing fingerprints of each material and comparable data for checking the consistence of the results. It was also shown that the elements penetration depth values in each tooth are usually similar and consistent, for both deciduous and permanent teeth, indicating that all the metals diffuse into the dentin by the same mechanism. We propose that this diffusion mechanism is mainly through liquid dragging inside the dentin tubules. The mercury diffused further in permanent teeth than in deciduous teeth, probably due to the longer diffusion times due to the age of the restorations. It was possible to conclude that the proposed femtosecond-LIBS system can detect the presence of metals in the dental tissue, among the tooth constituent elements, and map the distribution of endogenous and exogenous chemical elements, with a spatial resolution that can be brought under 100 µm.

  7. Taking Care of Your Teeth

    MedlinePlus

    ... re choosing a toothpaste, make sure it contains fluoride . Fluoride makes your teeth strong and protects them from ... MORE ON THIS TOPIC Movie: Teeth How Does Fluoride Work? Bad Breath Going to the Dentist Going ...

  8. Mouth and Teeth (For Parents)

    MedlinePlus

    ... infection, a dentist might need to remove them. Human teeth are made up of four different types of ... previous continue Normal Development of the Mouth and Teeth Humans are diphyodont, meaning that they develop two sets ...

  9. The effects of periradicular inflamation and infection on a primary tooth and permanent successor.

    PubMed

    Cordeiro, Mabel Mariela Rodriguez; Rocha, Maria Jose de Carvalho

    2005-01-01

    Primary teeth and the permanent successors must be understood as interdependent units, where each one of them interacts with and depends on each other. Pulpal inflammation/infection of a primary tooth and the spread of this condition over the periradicular tissues can lead to alterations in the dental germ of the permanent successor and to the surrounding structures if no therapy is done, i.e. endodontics or extraction. This work will present cases of permanent teeth that showed alteration in eruption and / or in development, as a consequence of inflammation / infection of the preceding primary teeth, such as: hypoplasia, morphological alteration on the dental crown or total arrest of. radicular formation. The teeth analysed in this study belong to patients who attended the Universidade Federal de Santa Catarina Children's Dentistry Clinic. The earlier these lesions are diagnosed, the less were the destructive effects and the consequences on the primary tooth/permanent germ unit.

  10. 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.

  11. Dental anomalies in the primary dentition and their repetition in the permanent dentition: a diagnostic performance study.

    PubMed

    Marinelli, Andrea; Giuntini, Veronica; Franchi, Lorenzo; Tollaro, Isabella; Baccetti, Tiziano; Defraia, Efisio

    2012-01-01

    This study investigated the recurrence in the permanent dentition of dental anomalies of the primary dentition. A sample of 189 subjects (100 males, 89 females, mean age of 5 years and 7 months) with anomalies of primary teeth (tooth hypodontia, supernumerary teeth, geminated teeth, and fused teeth) was selected and re-analyzed at a mean age of 11 years and 2 months for the recurrence of the dental anomalies in the permanent dentition. As a control group, 271 subjects (123 males, 148 females) without dental anomalies in the primary dentition were selected. The recurrence in the permanent dentition of the dental anomalies in the primary dentition was evaluated by measures of diagnostic performance. The results showed high values for the repetition of hypodontia (positive likelihood ratio = 102.0); low score for the repetition of hyperdontia (positive likelihood ratio = 6.5); low positive likelihood ratio (9.1) for gemination of primary teeth resulting in supernumerary permanent teeth; high positive likelihood ratio (47.0) for fusion of primary teeth followed by missing permanent teeth. Dental anomalies in the primary dentition are associated with an increased likelihood of anomalies of the succedaneous permanent.

  12. Remarkable resilience of teeth

    PubMed Central

    Chai, Herzl; Lee, James J.-W.; Constantino, Paul J.; Lucas, Peter W.; Lawn, Brian R.

    2009-01-01

    Tooth enamel is inherently weak, with fracture toughness comparable with glass, yet it is remarkably resilient, surviving millions of functional contacts over a lifetime. We propose a microstructural mechanism of damage resistance, based on observations from ex situ loading of human and sea otter molars (teeth with strikingly similar structural features). Section views of the enamel implicate tufts, hypomineralized crack-like defects at the enamel–dentin junction, as primary fracture sources. We report a stabilization in the evolution of these defects, by “stress shielding” from neighbors, by inhibition of ensuing crack extension from prism interweaving (decussation), and by self-healing. These factors, coupled with the capacity of the tooth configuration to limit the generation of tensile stresses in largely compressive biting, explain how teeth may absorb considerable damage over time without catastrophic failure, an outcome with strong implications concerning the adaptation of animal species to diet. PMID:19365079

  13. Odontomas—silent tormentors of teeth eruption, shedding and occlusion

    PubMed Central

    Kulkarni, Vinaya Kumar; Deshmukh, Jeevanand; Banda, Naveen Reddy; Banda, Vanaja Reddy

    2012-01-01

    Odontomas are the most common odontogenic tumours of the jaws, characterised by their slow growth and non-aggressive behaviour. They usually remain asymptomatic, and are diagnosed on routine radiographs. Clinically, they are often associated with delayed eruption or impaction of permanent teeth and retained primary teeth. The purpose of this paper is to review the literature and report two cases of odontomas. In the first case, a compound odontoma was associated with an unerupted maxillary permanent right central incisor, in an 11-year-old boy. In the second case, a 12-year-old girl had retained mandibular primary left central incisor and its unerupted successor was associated with a compound odontoma, a site considered rare for compound odontoma to occur. The clinical features, diagnosis and treatment of these cases have been discussed. PMID:23242095

  14. Bilateral agenesis of maxillary permanent canines: Review of the literature

    PubMed Central

    Borzabadi-Farahani, Ali

    2015-01-01

    Oligodontia, or agenesis of six or more teeth, excluding third molars, which involves canine agenesis is rare, and restorative management can be challenging. Bilateral agenesis of a permanent canine in the general population often indicates a several missing adult teeth. The most common sign of it is the primary canine retention beyond its exfoliation age. The multistage restorative management includes the early diagnosis, excluding associated medical problems as well as assessment of patient's malocclusion and facial skeletal pattern, life span of deciduous teeth, possibility of premolar substitution, minimum required number of prosthetic units, patient's preferences, and the cost of treatment. A 10-year-old boy with bilateral agenesis of maxillary permanent canines is described. Some thoughts on the multidisciplinary restorative management of this case are discussed. PMID:25657989

  15. Incremental enamel development in modern human deciduous anterior teeth.

    PubMed

    Mahoney, Patrick

    2012-04-01

    This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age-at-death estimates. Regression equations for reconstructing formation time in worn incisors are given.

  16. Bilateral distal ectopic eruption of the permanent mandibular central incisors: a case report.

    PubMed

    Portela, Maristela Barbosa; Sanchez, Ana Lúcia Freire; Gleiser, Rogério

    2003-02-01

    A 7-year-old female patient presented with a rare case of bilateral distal ectopic eruption of the mandibular permanent central incisors. Treatment instituted was extraction of the retained primary teeth and placement of a fixed appliance for alignment and repositioning of the mandibular permanent incisors.

  17. Specialized stem cell niche enables repetitive renewal of alligator teeth.

    PubMed

    Wu, Ping; Wu, Xiaoshan; Jiang, Ting-Xin; Elsey, Ruth M; Temple, Bradley L; Divers, Stephen J; Glenn, Travis C; Yuan, Kuo; Chen, Min-Huey; Widelitz, Randall B; Chuong, Cheng-Ming

    2013-05-28

    Reptiles and fish have robust regenerative powers for tooth renewal. However, extant mammals can either renew their teeth one time (diphyodont dentition) or not at all (monophyodont dentition). Humans replace their milk teeth with permanent teeth and then lose their ability for tooth renewal. Here, we study tooth renewal in a crocodilian model, the American alligator, which has well-organized teeth similar to mammals but can still undergo life-long renewal. Each alligator tooth is a complex family unit composed of the functional tooth, successional tooth, and dental lamina. Using multiple mitotic labeling, we map putative stem cells to the distal enlarged bulge of the dental lamina that contains quiescent odontogenic progenitors that can be activated during physiological exfoliation or artificial extraction. Tooth cycle initiation correlates with β-catenin activation and soluble frizzled-related protein 1 disappearance in the bulge. The dermal niche adjacent to the dermal lamina dynamically expresses neural cell adhesion molecule, tenascin-C, and other molecules. Furthermore, in development, asymmetric β-catenin localization leads to the formation of a heterochronous and complex tooth family unit configuration. Understanding how these signaling molecules interact in tooth development in this model may help us to learn how to stimulate growth of adult teeth in mammals.

  18. Congenital adrenal hyperplasia: a case report with premature teeth exfoliation and bone resorption.

    PubMed

    Angelopoulou, Matina V; Kontogiorgos, Elias; Emmanouil, Dimitris

    2015-06-01

    Congenital adrenal hyperplasia (CAH) is an inherited autosomal recessive disorder characterized by insufficient production of cortisol. The aim of this case report was to present a child with CAH, premature exfoliation of primary teeth and accelerated eruption of his permanent teeth related to bone resorption. A 4.5-year-old Caucasian boy with CAH and long-term administration of glucocorticoids was referred for dental restoration. Clinical examination revealed primary molars with worn stainless steel crowns, severe attrition of the upper canines, and absence of the upper incisors. Before the completion of treatment, abnormal mobility of the first upper primary molars and the lower incisors was detected, and a few days later the teeth exfoliated prematurely. Histologic examination revealed normal tooth structure. Alkaline phosphatase and blood cells values were normal. Eruption of the permanent dentition was also accelerated. Tooth mobility was noticed in the permanent teeth as soon as they erupted, along with bone destruction. Examination revealed an elevated level of receptor activator of nuclear factor-κB ligand and lower-than-normal osteoprotegerin and vitamin D levels. The patient was treated with vitamin D supplements, and his teeth have been stable ever since. CAH is a serious chronic disorder appearing in children with accelerated dental development and possibly premature loss of primary teeth.

  19. Sterilization of Extracted Human Teeth.

    ERIC Educational Resources Information Center

    Pantera, Eugene A., Jr.; Schuster, George S.

    1990-01-01

    At present, there is no specific recommendation for sterilization of extracted human teeth used in dental technique courses. The purpose of this study was to determine whether autoclaving would be effective in the sterilization of extracted teeth without compromising the characteristics that make their use in clinical simulations desirable. (MLW)

  20. Histological and Ultrastructure Analysis of Dentin Dysplasia Type I in Primary Teeth: A Case Report.

    PubMed

    Pintor, Andrea; Alexandria, Adilis; Marques, Andrea; Abrahao, Aline; Guedes, Fabio; Primo, Laura

    2015-01-01

    Dentin dysplasia type I (DD-I) is a rare human dentin disorder that may affect both the primary and permanent dentitions. The teeth present crowns with normal morphology but short or absent roots. Pulp chamber obliteration and early exfoliation of primary teeth are also observed. We describe herein the typical and atypical features of DD-I presented by a 6-year-old patient, the diagnostic rationale and assessment emphasizing the histological and scanning electron microscopic analysis and the therapeutic approach. The DD-I diagnosis in patients in the mixed dentition period is challenging, especially when only some teeth are affected.

  1. Adjuncts to traditional local anesthesia techniques in instance of hypomineralized teeth.

    PubMed

    Discepolo, Keri E; Baker, Suher

    2011-11-01

    Molar incisor hypomineralization (MIH) is a defect in the enamel of permanent and/or primary molars and incisors. This disorder allows for rapid breakdown of the teeth and often calls for extensive restorative procedures. Due to the chronic pulpitis condition that is often associated with hypomineralized teeth, local anesthesia complications can result. This paper is a systematic review of the literature for the purpose of investigating adjuncts to traditional local anesthesia techniques in the case of hyper-responsive, hypomineralized-involved teeth during restorative procedures.

  2. Triple Teeth: Report of an Unusual Case

    PubMed Central

    Babaji, Prashant; Prasanth, M. A.; Gowda, Ajith R.; Ajith, Soumya; D'Souza, Henston; Ashok, K. P.

    2012-01-01

    Fusion or synodontia is a union of two or more than two developing teeth. Commonly fusion occurs between teeth of the same dentition, mixed dentition, or between normal and supernumerary teeth. Fused primary teeth present with several clinical problems like caries, periodontal problem, arch asymmetry, delayed eruption, ectopic eruption of succedaneous teeth, aesthetic, and other complications. This paper presents a rare and unusual case of triple teeth in mandibular primary dentition. PMID:23346424

  3. Periodontal ligament stem cells modulate root resorption of human primary teeth via Runx2 regulating RANKL/OPG system.

    PubMed

    Li, Bei; Zhang, Yu; Wang, Qingchao; Dong, Zhiwei; Shang, Linjuan; Wu, Lizheng; Wang, Xiaojing; Jin, Yan

    2014-10-15

    Physiological primary teeth exfoliation is a normal phenomenon during teeth development. However, retained primary teeth can often be observed in the patients with cleidocranial dysplasia (CCD) caused by mutation of Runx2. The potential regulative mechanism is still unknown. In the present study, periodontal ligament stem cells (PDLSCs) were derived from different resorbed stages of primary teeth and permanent teeth from normal patients and primary teeth from CCD patient. The proliferative, osteogenic and osteoclast-inductive capacities of PDLSCs from each group were detected. We demonstrated here that the proliferative ability of PDLSCs was reduced while the osteogenic and the osteoclast-inductive capacity of PDLSCs were enhanced during root resorption. The results also showed that PDLSCs from permanent teeth and CCD patient expressed low level of Runx2 and RANKL while high level of OPG. However, expression of Runx2 and RANKL were increased while expression of OPG was decreased in PDLSCs derived from resorbed teeth. Furthermore, Runx2 regulating the expression of RANKL and OPG and the osteoclast-inductive capacity of PDLSCs were confirmed by gain or loss of function assay. These data suggest that PDLSCs promote osteoclast differentiation via Runx2 upregulating RANKL and downregulating OPG, leading to enhanced root resorption that results in physiological exfoliation of primary teeth.

  4. Relationship of cheek tooth abrasion to fluoride-induced permanent incisor lesions in livestock.

    PubMed

    Shupe, J L; Christofferson, P V; Olson, A E; Allred, E S; Hurst, R L

    1987-10-01

    Teeth from cattle, sheep, and horses that ingested various fluoride intakes and teeth from field studies of these species plus deer, elk, and bison were examined for abnormalities. Approximately 99,000 animals in 322 herds were examined for fluorosis. From field studies, 988 cattle of various ages and with different degrees of dental fluorosis were slaughtered and necropsied. The severity of fluoride-induced mottling, hypoplasia, and abnormal abrasion of paired permanent incisor teeth was correlated with abrasion of premolar and molar (cheek) teeth that form and mineralize at approximately the same age. Severe irregular wear of cheek teeth impaired mastication and resulted in poor utilization of feed and unthriftiness. Excessive amounts of fluoride during tooth formation and mineralization induce characteristic dental changes. Offspring from the fluoride-affected animals did not have discernible fluoride-induced lesions in the deciduous teeth.

  5. Disinclusion of unerupted teeth by mean of self-ligating brackets: Effect of blood contamination on shear bond strength

    PubMed Central

    Sfondrini, Maria F.; Gatti, Sara; Gandini, Paola

    2013-01-01

    Objectives: The aim of this study was to assess the effect of blood contamination on the shear bond strength and failure site of three different orthodontic self-ligating brackets. Study Design: 240 bovine permanent mandibular incisors were randomly divided into 12 groups of 20 specimens each. Orthodontic self-ligating brackets were tested under four different enamel surface conditions: a) dry, b) blood contamination before priming, c) blood contamination after priming, d) blood contamination before and after priming. Brackets were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values), and Chi squared test (ARI Scores). Results: Non-contaminated enamel surfaces showed highest bond strengths for all self ligating brackets. Under blood-contamination shear bond strengths lowered for all brackets tested. Groups contaminated before and after primer application showed the lowest shear bond strength. Significant differences in debond locations were found among the groups under the various enamel surface conditions. Conclusions: Blood contamination of enamel during the bonding procedure lowers bond strength values of self ligating brackets, expecially when contamination occur in different times of the bonding procedure. Key words:Disinclusion, self ligating brackets, blood, contamination, enamel, orthodontics, oral surgery. PMID:23229253

  6. Supernumerary Teeth in Nepalese Children

    PubMed Central

    Singh, Varun Pratap

    2014-01-01

    Objective. The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth in a patient sample of Nepalese children. Study Design. A survey was performed on 2684 patients (1829 females and 1035 males) ranging in age from 6 to 14 for the presence of supernumerary teeth. For each patient with supernumerary teeth the demographic variables (age and sex), number, location, eruption status, and morphology were recorded. Descriptive statistics were performed. Results. Supernumerary teeth were detected in 46 subjects (1.6%), of which 26 were males and 20 were females with a male : female ratio of 1.3 : 1. The most commonly found supernumerary tooth was mesiodens followed by maxillary premolars, maxillary lateral incisor, and mandibular lateral incisor. Of the 55 supernumerary teeth examined, 58.18% (n = 32) had conical morphology, followed by tuberculate (30.90%, n = 17) and supplemental (10.90%, n = 6) forms. The majority of the supernumerary teeth were erupted (56.36%, n = 31). Conclusion. The prevalence of supernumerary teeth in Nepalese children was found to be 1.6%, the most frequent type being mesiodens. Conical morphology was found to be the most common form of supernumerary tooth. PMID:25506609

  7. Permanent Contraception for Women.

    PubMed

    Patil, Eva; Jensen, Jeffrey T

    2016-05-01

    Permanent contraception is a highly desired and commonly used contraceptive option for women around the world who desire never to become pregnant. Current methods of female permanent contraception require surgery. Postpartum tubal ligation and interval surgical tubal ligation are safe and effective, do not interfere with menstrual cycles, and require no ongoing cost or medical checkups. Hysteroscopic tubal occlusion offers a less invasive surgical approach, but requires an imaging study for verification of correct placement. However, not all women have access to a surgeon trained to provide permanent contraception, or they may face other prohibitive logistic or financial burdens. The development of novel permanent contraception methods that are immediately effective and/or nonsurgical could help improve access to and acceptability of permanent contraception. The expansion of permanent contraception options could help women achieve their family planning goals and reduce unintended pregnancies.

  8. Oscillating Permanent Magnets.

    ERIC Educational Resources Information Center

    Michaelis, M. M.; Haines, C. M.

    1989-01-01

    Describes several ways to partially levitate permanent magnets. Computes field line geometries and oscillation frequencies. Provides several diagrams illustrating the mechanism of the oscillation. (YP)

  9. Comparison of the mechanical effects of a toothbrush and standard abrasive on human and bovine dentine in vitro.

    PubMed

    Imfeld, T

    2001-01-01

    Dentine abrasion is an important possible side effect of individually used mechanical oral hygiene products. Since human teeth are sometimes not available in sufficient numbers for research purposes, bovine teeth are often used as a substitute for in vitro tests of dentine abrasion. The aim of the present comparative study was to determine the mechanical effects of a manual toothbrush and a standard abrasive on human and bovine dentine under standardized conditions. Roots of human and bovine teeth were radioactivated and subjected to standardized machine brushing using a manual toothbrush and a standard abrasive slurry. Dentine abrasion was assessed by measuring radioactive phosphorus contained in the slurry after brushing. Non-radioactive human and bovine roots were brushed in the same machine, and the generated surface roughness was assessed using profilometry. Artificially stained human and bovine roots were brushed as described, and the cleaning effect was expressed as the extent of stain-free surfaces after different brushing times. The results for abrasion and surface roughening found with bovine and human dentine suggest that if standardized methods are used, roots of bovine mandibular front teeth can be used in place of human roots for in vitro studies of the mechanical effects of toothbrushes and toothpastes on dentine. The use of bovine dentine for measuring the cleaning effects of these products is, however, not recommended.

  10. Dovetail spoke internal permanent magnet machine

    DOEpatents

    Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Shah, Manoj Ramprasad; VanDam, Jeremy Daniel

    2011-08-23

    An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

  11. Do Fluoride Ions Protect Teeth?

    ERIC Educational Resources Information Center

    Parkin, Christopher

    1998-01-01

    Begins with the procedure and results from an investigation on the effect of fluoride on the reaction between eggshell (substitute teeth) and dilute ethanoic acid. Describes an elegantly modified and improvised apparatus. (DDR)

  12. 77 FR 29914 - Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... RIN 0579-AC68 Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products AGENCY... live bovines and products derived from bovines with regard to bovine spongiform encephalopathy. This... with regard to bovine spongiform encephalopathy. Comments on the proposed rule were required to......

  13. Restoring primary anterior teeth.

    PubMed

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen.

  14. Permanent magnet assembly

    DOEpatents

    Chell, Jeremy; Zimm, Carl B.

    2006-12-12

    A permanent magnet assembly is disclosed that is adapted to provide a magnetic field across an arc-shaped gap. Such a permanent magnet assembly can be used, for example, to provide a time-varying magnetic field to an annular region for use in a magnetic refrigerator.

  15. Method and apparatus for assembling permanent magnet rotors

    DOEpatents

    Hsu, J.S.; Adams, D.J.

    1999-06-22

    A permanent magnet assembly for assembly in large permanent magnet motors and generators includes a two-piece carrier that can be slid into a slot in the rotor and then secured in place using a set screw. The invention also provides an auxiliary carrier device with guide rails that line up with the teeth of the rotor, so that a permanent magnet assembly can be pushed first into a slot, and then down the slot to its proper location. An auxiliary tool is provided to move the permanent magnet assembly into position in the slot before it is secured in place. Methods of assembling and disassembling the magnet assemblies in the rotor are also disclosed. 2 figs.

  16. Method and apparatus for assembling permanent magnet rotors

    DOEpatents

    Hsu, John S.; Adams, Donald J.

    1999-01-01

    A permanent magnet assembly (22) for assembly in large permanent magnet (PM) motors and generators includes a two-piece carrier (23, 24) that can be slid into a slot (13) in the rotor (10) and then secured in place using a set screw (37). The invention also provides an auxiliary carrier device (50) with guide rails (51) that line up with the teeth (12) of the rotor, so that a permanent magnet assembly (22) can be pushed first into a slot (13), and then down the slot (13) to its proper location. An auxiliary tool (50) is provided to move the permanent magnet assembly (22) into position in the slot (13) before it is secured in place. Methods of assembling and disassembling the magnet assemblies (22) in the rotor (10) are also disclosed.

  17. 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.

  18. Concentration of {sup 226}Ra in human teeth

    SciTech Connect

    Yamamoto, Masayoishi; Ueno, Kaoru; Hinoide, Moriyo; Ohkubo, Yoshiteru

    1994-11-01

    {sup 226}Ra concentrations in human teeth from several cities, mainly Tokyo, Japan, were determined with emphasis on the measurement of low-level {sup 226}Ra by alpha-ray spectrometry following chemical separation. No appreciable differences in {sup 226}Ra concentration were found among various permanent teeth samples of different age groups in Tokyo. The mean {sup 226}Ra concentration for Tokyo was 0.51 {+-} 0.06 mBq (g CA){sup -1}. {sup 226}Ra concentration [mean: 0.67 {+-} 0.11 mBq (g Ca){sup -1}] in teeth in western regions of the country was statistically higher than that [mean: 0.48 {+-} 0.09 mBq (g Ca){sup -1}] in eastern ones. The mean {sup 226}Ra concentration [0.51 mBq (g CA){sup -1}] in teeth from Tokyo was less than the concentration [1.11 mBq (g CA){sup -1}] reported for vertebral bone samples of this city. 27 refs., 1 fig., 5 tabs.

  19. Fracture resistance of weakened teeth restored using accessory glass fiber posts.

    PubMed

    da Rosa, Ricardo Abreu; Barreto, Mirela Sangoi; da Rosa, Tiago Abreu; Reis, Katia Rodrigues; Kaizer, Osvaldo Bazzan

    2013-01-01

    This study used differential root weakening to evaluate the fracture resistance of bovine teeth restored using glass fiber posts (with or without accessory glass fiber posts). Fifty bovine mandibular incisors were sectioned 14 mm from the apex, fixed in acrylic resin blocks, and divided into 5 groups: healthy roots with a glass fiber post (Group 1), partially weakened teeth with a glass fiber post (Group 2), partially weakened teeth with a glass fiber post and 2 accessory glass fiber posts (Group 3), extensively weakened teeth with a glass fiber post (Group 4), and extensively weakened teeth with a glass fiber post and 5 accessory glass fiber posts (Group 5). Posts were luted with resin cement, cores were prepared using composite resin, and metallic crowns were cemented. The specimens were stored in distilled water at 37°C for more than 72 hours until the fracture resistance test. Specimens were loaded at 135 degrees relative to the long axis of the tooth at a crosshead speed of 0.5 mm/minute in a universal testing machine. All groups predominantly exhibited favorable failure patterns and there were no statistically significant differences between groups (two-way ANOVA, α = 0.05).

  20. Non-syndromic concomitant hypodontia and supernumerary teeth in an orthodontic population.

    PubMed

    Varela, Margarita; Arrieta, Patricia; Ventureira, Cesar

    2009-12-01

    The simultaneous occurrence of hypodontia and supernumerary teeth in the same individual is termed 'concomitant hypo-hyperodontia' (CHH). There appears to be a correlation between CHH and some syndromes, but this anomaly is very rare in the general population. The aim of this study was to investigate the frequency of CHH in a large sample of non-syndromic orthodontic patients. The records of 2108 consecutive non-syndromic orthodontic patients aged from 7 to 16 years were examined retrospectively. Every patient had at least one panoramic radiograph. When the diagnosis of hypodontia and/or hyperodontia was made in a child under 10 years of age, a second panoramic film was taken 2-4 years later. Statistical analysis of the data was undertaken using a chi-square test. Single or multiple hypodontia was diagnosed in 137 patients (6.5 per cent), 62 males and 75 females. One or more supernumerary teeth were found in 42 patients (2 per cent), 22 males and 20 females. CHH was diagnosed in seven subjects (0.33 per cent), four males and three females. In the CHH subpopulation, the total number of absent and supernumerary teeth was nine and eight, respectively. Hypodontia always occurred in the permanent dentition and was more frequent in the mandible than in the maxilla (four versus three teeth). Supernumerary teeth were more frequent in the permanent than in the primary dentition (six versus two teeth). Five supernumeraries were located in the maxilla and three in the mandible.

  1. Determination of working length for teeth with wide or immature apices: a review.

    PubMed

    Kim, Y J A; Chandler, N P

    2013-06-01

    Practitioners face several challenges during the root canal treatment of teeth with wide or immature apices, one of which is working length determination. There is relatively little data regarding the value of radiography and electronic apex locator (EAL) use when root formation is incomplete, and supplementary measurement techniques may be helpful. This review considers length determination for canals with wide or completely open apices in permanent and primary teeth. The Ovid Medline, Web of Science and Scopus databases were searched individually and in combinations to August 2012 using the subject headings 'working length determination' and 'open apex' and revealed only one article. Further headings, 'tooth apex', 'apical constriction', 'resorption', 'foramen size', 'mature root apex', 'immature root apex', 'working length determination', 'apexification', 'open apices', 'open apex', 'open apical foramina', 'canal length determination', 'immature teeth', 'apical diameters', 'electronic apex locators', 'primary teeth', 'treatment outcome' and 'clinical outcome' were entered. Potentially useful articles were chosen for a manual search of bibliography as well as a forward search of citations. Other investigations revealed case reports and some research related to open apices and laboratory studies evaluating EALs, radiography and tactile methods. Some involved permanent teeth of various apical diameters and primary teeth with and without resorption. There is a need to define the term 'open apex'. Clinicians should be aware of the benefits and limitations of all canal measuring techniques involved in managing this problem.

  2. A Case Report of Dilacerated Crown of a Permanent Mandibular Central Incisor.

    PubMed

    Bolhari, Behnam; Pirmoazen, Salma; Taftian, Ensieh; Dehghan, Somayeh

    2016-11-01

    Trauma to primary teeth can lead to devastating sequels in development of permanent successors. The disturbance may range from enamel hypoplasia and/or hypo-calcification to arrest of dental bud development. Crown dilaceration of permanent teeth is one of the consequences of trauma to deciduous teeth mainly due to intrusion or avulsion. This report presents a mandibular central incisor with dilacerated crown and yellowish discoloration with symptomatic apical abscess. History revealed avulsion of primary mandibular central incisors. The purpose of this report is to present: 1. Reasons of dilacerated crown, yellowish discoloration and necrotic pulp in this case, 2. Treatment options in different types of crown dilacerations and also in this case. The tooth was successfully managed by nonsurgical root canal therapy and restoration with composite resin to restore esthetics. We emphasize that trauma to deciduous teeth should not be understated, and regular follow up is essential.

  3. A Case Report of Dilacerated Crown of a Permanent Mandibular Central Incisor

    PubMed Central

    Bolhari, Behnam; Pirmoazen, Salma; Taftian, Ensieh

    2016-01-01

    Trauma to primary teeth can lead to devastating sequels in development of permanent successors. The disturbance may range from enamel hypoplasia and/or hypo-calcification to arrest of dental bud development. Crown dilaceration of permanent teeth is one of the consequences of trauma to deciduous teeth mainly due to intrusion or avulsion. This report presents a mandibular central incisor with dilacerated crown and yellowish discoloration with symptomatic apical abscess. History revealed avulsion of primary mandibular central incisors. The purpose of this report is to present: 1. Reasons of dilacerated crown, yellowish discoloration and necrotic pulp in this case, 2. Treatment options in different types of crown dilacerations and also in this case. The tooth was successfully managed by nonsurgical root canal therapy and restoration with composite resin to restore esthetics. We emphasize that trauma to deciduous teeth should not be understated, and regular follow up is essential. PMID:28243307

  4. Biodentine Pulpotomy in Mature Permanent Molar: A Case Report

    PubMed Central

    2016-01-01

    Irreversible pulpitis is the most common reason for endodontic treatment in primary and permanent teeth. Root canal therapy and extraction are the two viable and most documented treatment options for the same. Studies with regards to management of mature permanent teeth with carious exposure and treatment with vital pulp therapies such as adult permanent tooth pulpotomy are scarce. However, permanent tooth pulpotomy with the new calcium-silicate based cements (Mineral Trioxide Aggregate and Biodentine) can help preserve the tooth pulp vitality and promote healing and repair foregoing the more invasive root canal therapy procedure. A 12-year old male patient with irreversible pulpitis in right mandibular first permanent molar was treated with complete coronal pulpotomy with placement of Biodentine in the pulp chamber and a full coronal coverage using stainless steel crown. Clinical and radiographic examinations were performed at three, six, twelve and eighteen months. At the end of 18 months, the patient was completely asymptomatic and the tooth was free of any clinical and radiographic signs of inflammation and infection. PMID:27630966

  5. Restoration of endodontically treated anterior teeth: an evaluation of coronal microleakage of glass ionomer and composite resin materials.

    PubMed

    Diaz-Arnold, A M; Wilcox, L R

    1990-12-01

    A glass ionomer material was evaluated for coronal microleakage in permanent lingual access restorations of endodontically treated anterior teeth. The material was tested as a restoration, placed over a zinc oxide-eugenol base, and as a base with an acid-etched composite resin veneer and a dentinal bonding agent. Restored teeth were thermocycled, immersed in silver nitrate, developed, and sectioned to assess microleakage. Significant coronal leakage was observed with all materials used.

  6. Performance comparison of three-phase flux reversal permanent magnet motors in BLDC and BLAC operation mode

    NASA Astrophysics Data System (ADS)

    Štumberger, B.; Štumberger, G.; Hadžiselimović, M.; Hamler, A.; Goričan, V.; Jesenik, M.; Trlep, M.

    The paper presents a comparison of torque capability and flux-weakening performance of three-phase flux reversal permanent magnet motors with surface and inset permanent magnets. Finite element analysis is employed to determine the performance of each motor in BLDC and BLAC operation mode. It is shown that the torque capability and flux-weakening performance of surface or inset permanent magnet configuration is strongly dependent on the stator teeth number/rotor pole number combination.

  7. Clinical and radiological evaluation of inverse impaction of supernumerary teeth

    PubMed Central

    Kurklu, Esma; Gencay, Koray; Ak, Gulsum

    2013-01-01

    Objective: To describe the clinical and radiological features of children with inverted supernumerary teeth. Study Design: Thirty eight patients with inverted supernumerary teeth (ST) were enrolled in this descriptive and restrospective study. Data from patient records including age, gender, status of dentition, number of ST, number of ST in inverted position, coexistence of ST in inverted and normal direction of eruption, location, orientation, morphology, clinical complications, management and radiography were assessed during 3-years period. Results: Thirty eight patients with a mean age of 9.10±1.97 years (range:6-13) and a strong male preponderance of 3.7:1 (male:30, female:8) had a total of 69 ST, of which 41 were in inverted position. Thirty five patients had one (92.1%) inverted tooth, whereas 3 patients had two inverted teeth per case (7.9%). All cases were located in the maxilla. Midline was the most frequent site for the single inverted supernumerary tooth in 18 (47.4%) patients, followed equally by the right and left premaxillary region in 10 patients each (26.3%). Regarding morphology, 30 patients had conical (78.9%) and 8 (21.1%) had incisiform ST. No tuberculate shaped ST was detected. There was no statistically significant difference between number of inverted teeth and delayed tooth eruption, diastema, local malocclusion, palatinal swelling (p>0.05). There was no statistically significant difference between complications and age (p>0.05). Surgical removal at the time of diagnosis with subsequent follow-up during completion of permanent dentition was the treatment approach in all cases. Conclusions: Thorough clinical examination followed by a comprehensive radiographic screening is the crucial determinant of an accurate diagnosis of an impacted ST. Early diagnosis and timely management are key factors to prevent or minimize the complications, which may influence function and esthetics of the teeth and even psychological condition of the growing

  8. Preprosthetic movement of anterior teeth.

    PubMed

    Melsen, B

    1982-05-01

    Preprosthetic movement of anterior teeth is often performed on patients with missing anterior teeth, providing a better basis for subsequent bridgework. This can often be achieved by horizontal tooth movements of a tipping or translatory art whilst other patients present problems of a vertical nature with a deep overbite inconsistent with a healthy periodontal status. Intrusive tooth movements are needed as changes in facial height are not tolerated. The importance of understanding the biological basis for tooth movements in the planning of the biomechanics is stressed. Forces should be monitored according to the amount of general and local bone loss.

  9. Elemental Analysis of Asian Elephant (Elephas maximus) Teeth Using X-ray Fluorescence and a Comparison to Other Species.

    PubMed

    Nganvongpanit, Korakot; Brown, Janine L; Buddhachat, Kittisak; Somgird, Chaleamchat; Thitaram, Chatchote

    2016-03-01

    Elemental composition in bone of the different species has variation depending on genetic and environmental factors especially their food habitat. The aims of this study were to conduct an elemental analysis of Asian elephant teeth, both deciduous (first molar, second molar, and tusk) and permanent (molar and tusk), and compare the elemental composition of permanent teeth among 15 species, mostly mammalian. These teeth were analyzed using X-ray fluorescence at two voltages: 15 and 50 kV. In Asian elephants, deciduous tusk showed a lower Ca/Zn ratio compared to permanent tusk, because of the lack of Zn in permanent molars. Ca/Fe ratio was higher in deciduous than permanent molars. For permanent teeth, elephant molars presented a high Ca/Pb ratio but no Ca/Zn, Ca/Sr, and Zn/Fe ratios because of the lack of Zn and Sr in the samples tested. The key elemental ratios for differentiating elephant deciduous and permanent tusk were Ca/P and Ca/Zn. The considerable variation in elemental ratio data across 15 species was observed. All tooth samples contained Ca and P, which was not surprising; however, Pb also was present in all samples and Cd in a large majority, suggesting exposure to environmental contaminants. From discriminant analysis, the combination of Ca/P+Ca/Zn+Ca/Pb+Ca/Fe+Ca/Sr+Zn/Fe can generate two equations that successfully classified six (dog, pig, goat, tapir, monkey, and elephant) out of 15 species at 100 % specificity. In conclusion, determining the elemental profile of teeth may serve as a tool to identify the tooth "type" of elephants and to potentially classify other species.

  10. Clinical survey of fractured teeth.

    PubMed

    Gher, M E; Dunlap, R M; Anderson, M H; Kuhl, L V

    1987-02-01

    Through a standardized procedure using clinical examination, interviews, and dental history, this 2-year study documents 100 cases of tooth fracture in 98 patients. For comparison, pertinent information was also recorded for more than 2,000 teeth in a randomly selected sample population. Two chief types of fracture were found: incomplete crown-root fractures and root fractures associated with earlier endodontic therapy.

  11. Apoptosis in pulp elimination during physiological root resorption in human primary teeth.

    PubMed

    Rodrigues, Luciana Villela; Vasconcelos, Anilton César; Campos, Pedro Alves; Brant, Juliana Massote Caldeira

    2009-01-01

    Pulp samples of 50 healthy human teeth with indication for extraction were examined to evaluate the role of apoptosis in pulp elimination during physiological root resorption. Two groups were formed: a test group (n=30) composed of pulp samples of primary teeth with physiological root resorption and a control group (n=20) composed of pulp samples of permanent maxillary third molars. Morphological evidence of apoptosis as well as in situ detection of cellular DNA fragmentation by TUNEL assay and detection of internucleosomal pattern of fragmentation of the genomic DNA by electrophoresis were observed. The apoptotic index of the primary tooth group was significantly higher than that of the permanent tooth group (51.01 +/- 0.52 versus 25.32 +/- 0.68) (p<0.001). TUNEL reaction showed intense and diffuse labeling in the pulp samples of primary teeth, which were discrete in the controls. Intense DNA internucleosomal fragmentation, a specific pattern for apoptosis, was observed in primary tooth pulps DNA by electrophoresis, in the permanent tooth pulps this pattern fragmentation of the genomic DNA for apoptosis were not present. These results seem to indicate a role of apoptosis in pulp elimination during the physiological root resorption of human primary teeth.

  12. Take Care of Your Child's Teeth

    MedlinePlus

    ... This Topic En español Take Care of Your Child’s Teeth Browse Sections The Basics Overview Tooth Decay ... can cause cavities (holes) in teeth. Is my child at risk for tooth decay? Tooth decay is ...

  13. Management of a Nonvital Young Permanent Tooth by Pulp Revascularization

    PubMed Central

    Chandran, Vidya; Sivadas, G

    2014-01-01

    ABSTRACT% This report presents the case of a 10-year-old patient with a nonvital young permanent tooth which was managed by pulp revascularization. Following disinfection of the canal by irrigation with NaOCl and use of a triantibiotic paste, a scaffold was created by inducing the formation of a blood clot within the canal. At the subsequent follow-up visits, the patient was asymptomatic, with normal response to percussion, normal periodontal probing depths, and no abnormal mobility. The radiographs showed evidence of continued apical root development with increase in root length, signs of apical closure and increase in thickness of dentinal walls. Thus, this case adds to the growing evidence supporting the revascularization approach as an option for management of nonvital young permanent teeth. How to cite this article: Chandran V, Chacko V, Sivadas G. Management of a Nonvital Young Permanent Tooth by Pulp Revascularization. Int J Clin Pediatr Dent 2014;7(3):213-216. PMID:25709305

  14. First permanent molar root development arrest associated with compound odontoma.

    PubMed

    Gunda, Sachin A; Patil, Anil; Varekar, Aniruddha

    2013-07-04

    Trauma or infection to the primary tooth may have deleterious effects on the underlying developing tooth buds. Anatomically the root apices of primary teeth are in close proximity to the developing permanent tooth buds; hence spread of infection originating from pulp necrosis of primary tooth may not only affect the underlying tooth bud but may also affect the adjacent tooth buds. The extent of malformation depends on the developmental stage of tooth or the age of patient. Presented here is a rare case of complete arrest of maxillary first permanent molar root growth due to spread of periapical infection originating from second primary molar leading to failure of its eruption and finally extraction. Histopathlogical analysis revealed compound odontoma associated with maxillary first permanent molar.

  15. Ectopic eruption of the maxillary central permanent incisors and mandibular first permanent molars: report of an unusual case.

    PubMed

    Pomarico, Luciana; Primo, Laura Guimarães; Noce, Denise

    2006-10-01

    Ectopic eruption is a disturbance in which the tooth does not follow its usual course. Among its more important etiologic factors are macrodontism, shortened arch length, posterior positioning of the maxilla, atypical eruption angle, and genetic factors. This article reports a rare case of ectopic eruption of 4 permanent teeth, maxillary central incisors and mandibular first molars, in a child aged 7 years and 11 months, in which the treatment consisted of extracting the maxillary primary central incisors and making an orthodontic intervention on the mandibular arch. A bilateral fixed appliance containing 2 hooks with loops, 1 buccal and the other lingual, was placed on the mandibular primary first molars. The hooks were activated in a niche made of light-curing resin on the occlusal surface of the mandibular permanent molars, to bring about the distal drift of these teeth. After 6 months, complete eruption of the mandibular permanent molars occurred, and a slight displacement of the maxillary permanent central incisors toward the median line was noted. The importance of early, adequate treatment is discussed.

  16. Cracked Teeth: A Review of the Literature

    PubMed Central

    Lubisich, Erinne B.; Hilton, Thomas J.; FERRACANE, JACK

    2013-01-01

    Although cracked teeth are a common problem for patients and dentists, there is a dearth of evidence-based guidelines on how to prevent, diagnose, and treat cracks in teeth. The purpose of this article is to review the literature to establish what evidence exists regarding the risk factors for cracked teeth and their prevention, diagnosis, and treatment. PMID:20590967

  17. Analysis of colored teeth from Precolumbian Tlatelolco: postmortem transformation or intravitam processes?

    PubMed

    Mansilla, J; Solis, C; Chávez-Lomeli, M E; Gama, J E

    2003-01-01

    The etiological basis of the abnormal coloration of archaeological teeth has been an unsolved question for a long time. Differences in the appearance of some archaeological teeth from Precolumbian adult and infant skeletons, detected by external optical inspection, led us to study this problem. A blue stain is visible in a few of the deciduous erupted teeth, and a brown color in various unerupted teeth in the collection, while brown spots appear on some permanent teeth. Several processes or factors that may occur during one's life, others around the time of death, and still others resulting from postmortem alterations have been reported as potential causes of abnormal tooth coloration.A sample of 35 colored teeth and two soil layers taken from Tlatelolco were analyzed by particle-induced X-ray emission (PIXE) as well as selective dissolution techniques. Concentrations of total and extractable elements in enamel and soil layers (Cg1-Cg2) were obtained. This paper describes the occurrence and implications of a substantial secondary concentration of Zinc (Zn), manganese (Mn), strontium (Sr), and iron (Fe) in the deciduous erupted and nonerupted teeth as compared to that in the adult teeth. Our interpretation is that, in this archaeological context, the brown spots and blue stains on the teeth are due to differences in tooth enamel porosity and to a postmortem biogeochemical process. The alterations involve cumulization and diagenesis of iron, manganese, and organic matter solutions that were eluviated from the soil and are not the result of antemortem or perimortem conditions such as trauma or disease.

  18. Removal of Supernumerary Teeth Utilizing a Computer-Aided Design/Computer-Aided Manufacturing Surgical Guide.

    PubMed

    Jo, Chanwoo; Bae, Doohwan; Choi, Byungho; Kim, Jihun

    2016-11-12

    Supernumerary teeth need to be removed because they can cause various complications. Caution is needed because their removal can cause damage to permanent teeth or tooth germs in the local vicinity. Surgical guides have recently been used in maxillofacial surgery. Because surgical guides are designed through preoperative analysis by computer-aided design software and fabricated using a 3-dimensional printer applying computer-aided manufacturing technology, they increase the accuracy and predictability of surgery. This report describes 2 cases of removal of a mesiodens-1 from a child and 1 from an adolescent-using a surgical guide; these would have been difficult to remove with conventional surgical methods.

  19. A study of sub-occlusal secondary dentine thickness in overgrown equine cheek teeth.

    PubMed

    Marshall, R; Shaw, D J; Dixon, P M

    2012-07-01

    The presence of cheek tooth loss or defects, with subsequent overgrowth of the opposing teeth, is common in horses. Little is known about the factors that control the deposition of sub-occlusal secondary dentine (SO2D) in normal equine teeth, but these are likely to include stimulation of the occlusal surface. There appears to be no information on the possible alterations to this process when teeth develop overgrowths and, consequently, of the net effect on SO2D thickness caused by reduced stimulation of the occlusal surface and of absent/reduced normal occlusal wear (attrition). Knowledge of the likely thickness of SO2D in overgrown teeth may help reduce the risks of pulp horn exposure or thermal damage during therapeutic reduction of overgrowths. This study utilised 24 permanent cheek teeth (CT) with overgrowths (mean overgrowth height: 9.5 mm; range, 3.4-17.9 mm), and 18 control CT obtained from 15 horses of different breeds and ages. The thickness of SO2D was measured above 94 matched pulp horns in control and overgrown CT and showed a mean value of 12.14 mm (range 1.87-36.02 mm) in overgrown teeth and of 10.25 mm (range 2.64-17.26 mm) in controls. There was no significant difference between SO2D thickness in overgrown (mean 11.38 mm) and control (11.41 mm) mandibular CT, but SO2D was significantly thicker in overgrown (mean 12.57 mm) as compared to control maxillary (9.41 mm) CT. A comparison of SO2D thickness above the 94 matched pulp horns in overgrown and control teeth showed that 49% (46/94) of pulps in overgrown teeth had less SO2D overlying them than had control teeth. Of major clinical relevance was that the height of dental overgrowths was greater than SO2D thickness over one or more pulp horns in 14/24 overgrown teeth. Consequently, reduction of these overgrown teeth to the level of adjacent normal-height teeth would cause occlusal pulp exposure in 58% of teeth, in addition to possible thermal damage to additional pulp horns. It was concluded that

  20. Natal Teeth: A Case Report and Reappraisal

    PubMed Central

    Malki, Ghadah A.; Al-Badawi, Emad A.; Dahlan, Mohammad A.

    2015-01-01

    The presence of teeth at birth (natal teeth) or within a month after delivery (neonatal teeth) is a rare condition. Natal and neonatal teeth are conditions of significant importance to pediatric dentists and pediatricians. This report discusses a case in which a five-day-old infant required extraction of a mobile mandibular natal tooth to avoid the risk of aspiration and interference with feeding. Also, a review of the literature was conducted to discuss the etiology, clinical features, complications, and management of natal and neonatal teeth. PMID:25722895

  1. Genetic background of supernumerary teeth

    PubMed Central

    Subasioglu, Asli; Savas, Selcuk; Kucukyilmaz, Ebru; Kesim, Servet; Yagci, Ahmet; Dundar, Munis

    2015-01-01

    Supernumerary teeth (ST) are odontostomatologic anomaly characterized by as the existence excessive number of teeth in relation to the normal dental formula. This condition is commonly seen with several congenital genetic disorders such as Gardner's syndrome, cleidocranial dysostosis and cleft lip and palate. Less common syndromes that are associated with ST are; Fabry Disease, Ellis-van Creveld syndrome, Nance-Horan syndrome, Rubinstein-Taybi Syndrome and Trico–Rhino–Phalangeal syndrome. ST can be an important component of a distinctive disorder and an important clue for early diagnosis. Certainly early detecting the abnormalities gives us to make correct management of the patient and also it is important for making well-informed decisions about long-term medical care and treatment. In this review, the genetic syndromes that are related with ST were discussed. PMID:25713500

  2. 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.

  3. Analysis of developmental processes possibly related to human dental sexual dimorphism in permanent and deciduous canines.

    PubMed

    Moss, M L; Moss-Salentijn, L

    1977-05-01

    Analysis of published odontometric data on human dental sexual dimorphism indicates that this characteristic is most clearly expressed by the canine teeth. Review of the several processes involved in coronal odontogenesis suggests that such dimorphism is related to an absolutely longer period of amelogenesis for both deciduous and permanent dentitions.

  4. First Permanent Molar Restoration Differences between Those with or without Dental Sealants.

    ERIC Educational Resources Information Center

    Kuthy, Raymond A.; And Others

    1990-01-01

    The study examined differences in the number of restorations in permanent, posterior teeth for those children receiving dental sealants with cost sharing when compared to children who do not receive sealants. Results indicated a 51 percent reduction in restoration rates for each quadrant sealed. Findings have implications for cost savings and…

  5. Multiple pulp stones in primary and developing permanent dentition: a report of 4 cases.

    PubMed

    Marwaha, Mohita; Chopra, Radhika; Chaudhuri, Payal; Gupta, Atul; Sachdev, Jayna

    2012-01-01

    Pulp stones are foci of calcification or discrete calcifications in the dental pulp. They are frequently found on bitewing and periapical radiographs, but their occurrence in entire dentition is unusual. We are reporting four cases in which the occurrence of pulp stones ranged from their presence in just primary teeth (Cases 1 and 2) to involvement of young permanent teeth also (Case 3) and even unerupted permanent teeth (Case 4). In all the cases, dental, medical, and family histories as well as the findings from the clinical examination of the patient were not contributory. Histopathological report revealed true denticle. Metabolic evaluation of patients through liver function test, kidney function test, and blood investigation did not show any metabolic disorders. Patients were also evaluated for any systemic, syndromic, or genetic involvement, but this was also noncontributing. Therefore, it is suggested that these unusual cases may be of idiopathic origin.

  6. Bovine coronavirus associated syndromes.

    PubMed

    Boileau, Mélanie J; Kapil, Sanjay

    2010-03-01

    Bovine coronaviruses, like other animal coronaviruses, have a predilection for intestinal and respiratory tracts. The viruses responsible for enteric and respiratory symptoms are closely related antigenically and genetically. Only 4 bovine coronavirus isolates have been completely sequenced and thus, the information about the genetics of the virus is still limited. This article reviews the clinical syndromes associated with bovine coronavirus, including pneumonia in calves and adult cattle, calf diarrhea, and winter dysentery; diagnostic methods; prevention using vaccination; and treatment, with adjunctive immunotherapy.

  7. A case report of a rare finding of supernumerary primary and permanent canines

    PubMed Central

    Parker, Kate; Hay, Norman

    2014-01-01

    A supernumerary tooth is a tooth that is additional to the normal series of teeth. These can occur anywhere in the primary or permanent dentition and are most commonly found in the anterior maxilla. Supernumerary canines are rare with little available literature and case reports in this area. This case presents a patient with a unilateral maxillary supernumerary deciduous and permanent canine associated with an unusual cleft of the alveolus. How to cite the article: Parker K, Hay N. A case report of a rare finding of supernumerary primary and permanent canines. J Int Oral Health 2014;6(2):129-131. PMID:24876714

  8. Characterization of the calcium biomineral in the radular teeth of Chiton pelliserpentis.

    PubMed

    Evans, L A; Alvarez, R

    1999-04-01

    The radula in a group of molluscan invertebrates, the chitons (Polyplacophora), is a ribbon-like apparatus used for feeding and which bears a series of distinctive mineralized teeth called the major lateral teeth. While some chiton species deposit only iron biominerals in these teeth, many others deposit both iron and calcium. In this study, the calcium biomineral in the teeth of one of the latter types of species, the Australian east-coast chiton, Chiton pelliserpentis, has been isolated and examined for the first time. Spectroscopic and crystallographic techniques have identified the biomineral as a carbonate-substituted apatite with significant fluoride substitution also likely. Fourier-transform infrared and laser Raman spectroscopy indicated that the carbonate content was less than that of either bovine tibia cortical bone or human tooth enamel. X-ray diffraction analysis showed the biomineral to be poorly crystalline due to small crystal size and appreciable anionic substitution. The lattice parameters were calculated to be a = 9.382 A and c = 6.883 A, which are suggestive of a fluorapatite material. It is postulated that structural and biochemical differences in the tooth organic matrix of different chiton species will ultimately determine if the teeth become partly calcified or iron mineralized only.

  9. Variable Permanent Magnet Quadrupole

    SciTech Connect

    Mihara, T.; Iwashita, Y.; Kumada, M.; Spencer, C.M.; /SLAC

    2007-05-23

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

  10. [Orthodontic effects of tooth injury to the permanent and temporary incisors of children and the adolescent [corrected].

    PubMed

    Bassigny, F

    1990-01-01

    Traumatisms on the deciduous upper incisors could induce orthodontic indirect consequences on the permanent germ, dependent on his growth level and his malleability, dependent on connection between the root of deciduous incisor and the crown of permanent germ and according to the type of traumatism. According to those various data, it should be observed on the permanent incisor: germination of two germs, multiple odontoma, crown dilaceration, severe tipping of the crown with facial angulation, retention of the permanent germ with lack of root resorption of the deciduous teeth or simple cross-bite, without speaking of enamel defect.

  11. Managing Permanent Objects

    DTIC Science & Technology

    1984-11-01

    sorage me hanism is the Chunk Management System ( CMS ). CMS provides a database-like interface for POMW. On first reference to a permanent object POMS...19] M.P. Atkinson, K.J. Chisholm, and W.P. Cockshott. CMS - A Chunk Management System . Technical Report CSR-110-82, Department of Computer Science...database manager . Creating and using emibedded systems is not always bad. In most large programming projets one ends up constructing and using some sort

  12. Permanent magnet design methodology

    NASA Technical Reports Server (NTRS)

    Leupold, Herbert A.

    1991-01-01

    Design techniques developed for the exploitation of high energy magnetically rigid materials such as Sm-Co and Nd-Fe-B have resulted in a revolution in kind rather than in degree in the design of a variety of electron guidance structures for ballistic and aerospace applications. Salient examples are listed. Several prototype models were developed. These structures are discussed in some detail: permanent magnet solenoids, transverse field sources, periodic structures, and very high field structures.

  13. Postoperative permanent pressure alopecia.

    PubMed

    Chang, Zi Yun; Ngian, Jan; Chong, Claudia; Chong, Chin Ted; Liew, Qui Yin

    2016-04-01

    A 49-year-old Chinese female underwent elective laparoscopic assisted Whipple's surgery lasting 12 h. This was complicated by postoperative pressure alopecia at the occipital area of the scalp. Pressure-induced hair loss after general anaesthesia is uncommon and typically temporary, but may be disconcerting to the patient. We report this case of postoperative permanent pressure alopecia due to its rarity in the anaesthesia/local literature, and review the risk factors for its development.

  14. [Approach to pulpal and pulpo-periodontal lesions of the temporary teeth using therapeutic endodontics].

    PubMed

    Demars-Fremault, C; Pilipili, M C; Roupa, M

    1992-01-01

    The anatomical and physiological properties of deciduous teeth make them susceptible to caries and inflammatory and infectious complications. This specificity, the proximity of the germ of the underlaying permanent tooth, and the relation of the last one to the deciduous tooth, make delicate its conservation by endodontal therapeutics after a pulpal or pulpo-periodontal affection. The success of this attempt is related to a good case-selection, based on the general condition of the child, his and his parents motivation, the condition of cariogenicity of the mouth, the analysis of the unity deciduous tooth/germ of the underlaying permanent tooth, the follow-up of the case. A success spares young children extraction of the deciduous teeth before the physiological period of permutation.

  15. Intrusion and uprighting teeth for fixed prosthesis with temporary anchorage device.

    PubMed

    Palencar, Adrian J

    2012-01-01

    The mandibular first permanent molar is usually first to erupt around the age of six. Therefore, if the oral hygiene is not impeccable, it is usually also the first permanent tooth decayed in a child's mouth. A plethora of circumstances may lead to pulpal involvement, periapical pathosis, and endodontic treatment and in unfortunate situations, removal of this tooth. If this tooth is not replaced, or the extraction space is not retained for a considerable amount of time, the posterior occlusion will collapse. The most common occurrence is tipping of teeth in juxtaposition to the extraction site and extrusion of at least one opposing tooth. This article will describe efficient uprighting and intrusion of offending teeth prior to placement of fixed prosthesis. The author will explain the procedure step by step, first on acrylic models and then on the actual patient.

  16. Evaluation and Comparison of Changes in Microhardness of Primary and Permanent Enamel on Exposure to Acidic Center-filled Chewing Gum: An in vitro Study

    PubMed Central

    Muppa, Radhika; Srinivas, NCH; Kumar, Duddu Mahesh

    2014-01-01

    ABSTRACT Objectives: The study is to evaluate changes in microhardness of enamel after exposure to acidic center filled chewing gum on primary and permanent teeth. Methods: Thirty primary and 30 permanent molar extracted teeth were painted with acid resistant varnish except a small window over buccal surface. Teeth were divided into four groups according to type of teeth and type of chewing gum (Center fresh and Bubbaloo) (D1, P1, D2 and P2); each tooth was exposed to whole chewing gum mashed with 5 ml of artificial saliva for five minutes at room temperature twice a day for 5 days. After the exposure, teeth were stored in deionized water and submitted for microhardness tests. Results: Paired t-test and independent sample t-test were used for statistical analysis. A significant reduction in microhardness was found between exposed and unexposed areas in all groups. There was no statistically significant difference in reduction of microhardness to chewing gums, and between primary and permanent enamel. Conclusion: There is a definite reduction in microhardness in all groups exposed to chewing gums. Both the chewing gums are equally erosive; both permanent and primary teeth were affected. How to cite this article: Mudumba VL, Muppa R, Srinivas NCH, Kumar DM. Evaluation and Comparison of Changes in Microhardness of Primary and Permanent Enamel on Exposure to Acidic Center-filled Chewing Gum: An in vitro Study. Int J Clin Pediatr Dent 2014;7(1):24-29. PMID:25206233

  17. 77 FR 20319 - Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-04

    ...; ] DEPARTMENT OF AGRICULTURE Animal and Plant Health Inspection Service 9 CFR Part 93 RIN 0579-AC68 Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products Correction In proposed rule...

  18. 78 FR 73993 - Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-10

    ... Health Inspection Service 9 CFR Parts 92, 93, 94, 95, 96, and 98 RIN 0579-AC68 Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products Corrections In rule document 2013-28228 appearing...

  19. Mineral trioxide aggregate as a pulpotomy agent in immature teeth: Long-term case report

    PubMed Central

    Subay, Rustem Kemal; Ilhan, Banu; Ulukapi, Hasmet

    2013-01-01

    This case report aimed to present the long-term clinical performance of mineral trioxide aggregate (MTA) pulpotomies in immature permanent teeth. Four patients with complicated crown fractures of five maxillary immature central incisor teeth were treated with pulpotomy using gray MTA. An immature mandibular first molar showing signs of reversible pulpitis that was exposed mechanically during cavity preparation was also treated with MTA pulpotomy. Four of the 6 immature teeth were diagnosed vitally with complete root maturation and with the presence of dentin bridges after 55 months (mean time of follow-ups). MTA pulpotomy was assessed unsuccessfully in two fractured central incisors. Severe discoloration in the crowns was present in all 6 cases. MTA may induce pulp healing with dentin bridge formation and prevent necrosis at long-term periods in most of the pulpotomy cases. However, discoloration following MTA pulpotomy is a significant clinical complication. PMID:23408174

  20. Permanent Maxillary Canine Agenesis: A Rare Case Report

    PubMed Central

    Jain, Somya; Patil, Raju Umaji; Asokan, Alexander; Kambalimath, Deepashri

    2015-01-01

    ABSTRACT Congenitally missing teeth (CMT) are among one of the commonly known dental anomalies. The most frequently missing teeth in the permanent dentition, excluding the third molars, are mandibular second premolars and maxillary lateral incisors. Exclusive agenesis of both maxillary canines is an extremely rare occurrence and only a few cases have been reported. Previous studies showed that the prevalence of maxillary canine agenesis varies between 0.07 and 0.13%. In recent studies on Indian population, no cases of maxillary canine agenesis have been documented. This paper reports a case of non-syndromic bilateral agenesis of permanent maxillary canines, along with agenesis of both mandibular central incisors in a healthy 13-year-old Indian female patient; and a brief literature review on prevalence, etiology and treatment modalities of the condition. How to cite this article: Kambalimath HV, Jain S, Patil RU, Asokan A, Kambalimath D. Permanent Maxillary Canine Agenesis: A Rare Case Report. Int J Clin Pediatr Dent 2015; 8(3):242-246. PMID:26604546

  1. Vital Pulp Therapy of a Symptomatic Immature Permanent Molar with Long-Term Success

    PubMed Central

    Sabbagh, Sedigheh; Sarraf Shirazi, Alireza; Eghbal, Mohammad Jafar

    2016-01-01

    Vital pulp therapy (VPT) is the preferred conservative treatment for preservation of symptomatic pulps in immature permanent teeth. The present case report summarizes VPT of an immature permanent molar with irreversible pulpitis associated with apical periodontitis in a 9-year-old boy. Cervical pulpotomy was performed and radicular pulp stumps were covered with calcium-enriched mixture (CEM) cement; the tooth was then restored with stainless steel crown. After a 50-month follow-up period, the pulpotomized molar was clinically functional and asymptomatic. Moreover, radiographic evaluation revealed evidence of complete root development as well as normal periodontal ligament around the roots. The successful outcome achieved through VPT using CEM biomaterial in the reported case suggests that this method may produce favorable outcome for vital immature permanent teeth with irreversible pulpitis and periapical disease. PMID:27790270

  2. Apexogenesis of a symptomatic mandibular first permanent molar with calcium hydroxide pulpotomy.

    PubMed

    Kontham, Ujwal R; Tiku, Amita M; Damle, Satyawan G; Kalaskar, Ritesh R

    2005-09-01

    Vital pulp therapy of immature, symptomatic permanent posterior teeth presents a challenge in pediatric endodontics. A case report is presented in which cervical pulpotomy with calcium hydroxide was performed on a cariously exposed mandibular first permanent molar. The patient was seen every 3 months for a total of 18 months for a clinical and radiographic follow up. During the follow-up period, root development, as evidenced by root lengthening, was observed. Apical closure was evident at the end of 19 months. As the root canals showed a tendency toward calcification, root canal treatment was carried out, followed by restoration of the tooth with a stainless-steel crown. The success of this single-visit apexogenesis procedure supports the contention that young pulp possesses remarkable reparative capacity, as well as resistance to bacterial infection due to greater vascularity, and that apexogenesis with calcium hydroxide apical closure pulpotomy can be attempted for continued root development of symptomatic, vital, permanent teeth.

  3. Physiological Root End Closure in a Traumatized Young Permanent Tooth Using Collagen Particles as Pulpal Dressing

    PubMed Central

    Gaur, Divya; Kumar, CH Santosh; Shilpa, G

    2017-01-01

    The management of traumatized young permanent teeth has always been a challenge to the clinician, considering the importance of retaining the vitality of the tooth. Recently, collagen particles have been successfully used as pulpotomy medicaments in primary teeth. This case report shows the use of collagen particles as pulpal dressing in a traumatized young permanent tooth of a nine-year-old child presenting with complicated fracture of young permanent left maxillary central incisor. Partial pulpotomy was performed with collagen particles (Biofil-AB) as pulpal dressing. At six months follow up, apexogenesis was found to be nearly complete. Thus, collagen can be considered as a potential pulpal medicament for apexogenesis procedures. PMID:28274076

  4. [Esthetic restorations of primary anterior teeth].

    PubMed

    Elqadir, A Jamil; Shapira, J; Ziskind, K; Ram, D

    2013-04-01

    Esthetic treatment of primary teeth is one of the greatest challenges to pediatric dentists. A variety of restorative options using full coverage are available for anterior primary teeth. In the last half century the emphasis on treatment of severely decayed primary teeth shifted from extraction to restoration. In the past, restorations consisted of placement of stainless steel crowns on severely decayed teeth. However, they are esthetically unacceptable today. Over the last decade parents expect a higher esthetic standard for their children's primary teeth. Thus, the restoration should provide esthetic appearance and durability in addition to restoring function. The purpose of this review is to describe the types of full coverage options for anterior primary teeth currently available.

  5. Unlocking the bovine genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The draft genome sequence of cattle (Bos taurus) has now been analyzed by the Bovine Genome Sequencing and Analysis Consortium and the Bovine HapMap Consortium, which together represent an extensive collaboration involving more than 300 scientists from 25 different countries. ...

  6. Liquids with permanent porosity

    NASA Astrophysics Data System (ADS)

    Giri, Nicola; Del Pópolo, Mario G.; Melaugh, Gavin; Greenaway, Rebecca L.; Rätzke, Klaus; Koschine, Tönjes; Pison, Laure; Gomes, Margarida F. Costa; Cooper, Andrew I.; James, Stuart L.

    2015-11-01

    Porous solids such as zeolites and metal-organic frameworks are useful in molecular separation and in catalysis, but their solid nature can impose limitations. For example, liquid solvents, rather than porous solids, are the most mature technology for post-combustion capture of carbon dioxide because liquid circulation systems are more easily retrofitted to existing plants. Solid porous adsorbents offer major benefits, such as lower energy penalties in adsorption-desorption cycles, but they are difficult to implement in conventional flow processes. Materials that combine the properties of fluidity and permanent porosity could therefore offer technological advantages, but permanent porosity is not associated with conventional liquids. Here we report free-flowing liquids whose bulk properties are determined by their permanent porosity. To achieve this, we designed cage molecules that provide a well-defined pore space and that are highly soluble in solvents whose molecules are too large to enter the pores. The concentration of unoccupied cages can thus be around 500 times greater than in other molecular solutions that contain cavities, resulting in a marked change in bulk properties, such as an eightfold increase in the solubility of methane gas. Our results provide the basis for development of a new class of functional porous materials for chemical processes, and we present a one-step, multigram scale-up route for highly soluble ‘scrambled’ porous cages prepared from a mixture of commercially available reagents. The unifying design principle for these materials is the avoidance of functional groups that can penetrate into the molecular cage cavities.

  7. Permanent Turbidity-Standards

    PubMed Central

    Roessler, William G.; Brewer, Carl R.

    1967-01-01

    Permanent turbidity reference standards suitable for measurement of microbial suspensions were prepared by suspending finely divided titanium dioxide in aryl sulfonamide-formaldehyde or methylstyrene resins. Turbidities of these standards, adjusted to a useful range for microbiological and immunological studies, were compared with other reference standards in use today. Tube holders for a Coleman Photonephelometer and a Nepho-Colorimeter were modified to eliminate the water well and to allow use of optically standardized 10-, 16-, or 18-mm test tubes. The standards and the tube holders have been used satisfactorily for more than 12 years. Images Fig. 5 Fig. 6 PMID:6077410

  8. Permanence can be Defended.

    PubMed

    McGee, Andrew; Gardiner, Dale

    2017-03-01

    In donation after the circulatory-respiratory determination of death (DCDD), the dead donor rule requires that the donor be dead before organ procurement can proceed. Under the relevant limb of the Uniform Determination of Death Act 1981 (USA), a person is dead when the cessation of circulatory-respiratory function is 'irreversible'. Critics of current practice in DCDD have argued that the donor is not dead at the time organs are procured, and so the procurement of organs from these donors violates the dead donor rule. We offer a new argument here in defence of current DCDD practice, and, in particular, of the interpretation of the requirement of 'irreversibility' as permanence.

  9. Cryogenic Permanent Magnet Undulators

    SciTech Connect

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-06-23

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm{sub 2}Co{sub 17} or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  10. [Influence of food quality and quantity on children's teeth].

    PubMed

    Oka, A E; N'Cho, K J; Kattie, A L; Koffi, N A; Bakayoko-Ly, R

    2003-06-01

    Sugar and tooth decays are bound closely. The mechanisms of destruction of the tooth from the glycolyse are known. The role played by the food in the development of the caries is unique. Foods sweetened of all ways, rich in sucrose are responsible of the intervening of the carious lesions. The transformation of the fermentable sugars in lactic with the absence of hygiene and the action conjugated of the bacteria leads to tooth decays in temporary and permanent denture that evolve very quickly in the absence of treatment. Reasons for which the authors put in evidence in this survey, the influence of the food sweetened on the teeth at the children while showing the cases of caries and its complications due to the excessive consumption of fermentable hydrates of carbon.

  11. Management and Sequelae of Intruded Anterior Primary Teeth: A Systematic Review

    PubMed Central

    Murugan, Muthu; Somasundaram, Sujatha

    2016-01-01

    Objective The objective of this systematic review is to analyze the various treatment modalities and sequelae of intruded anterior primary teeth. Materials and methods Electronic search in PubMed, Cochrane, and Science Direct databases was done. Hand search was performed using the reference list of chosen articles from electronic search. Three reviewers analyzed the articles independently, assessed the quality of the studies, and derived data. Results Ten case series were identified from the electronic and hand search. No randomized control studies were available. In the observational studies treatment of intruded primary teeth ranged from conservative management, which includes waiting for spontaneous re-eruption as well as repositioning to invasive procedure, such as extraction. Conclusion Spontaneous eruption is a treatment option of intruded primary teeth in absence of damage to a permanent tooth. Surgical repositioning of intruded primary teeth has also shown as a viable alternative treatment modality. Extraction to be performed if complications develop. How to cite this article Gurunathan D, Murugan M, Somasundaram S. Management and Sequelae of Intruded Anterior Primary Teeth: A Systematic Review. Int J Clin Pediatr Dent 2016;9(3):240-250. PMID:27843257

  12. Banking stem cells from human exfoliated deciduous teeth (SHED): saving for the future.

    PubMed

    Arora, Vipin; Arora, Pooja; Munshi, A K

    2009-01-01

    Tooth derived cells are readily accessible and provide an easy and minimally invasive way to obtain and store stem cells for future use. Banking ones own tooth-derived stem cells is a reasonable and simple alternative to harvesting stem cells from other tissues. Obtaining stem cells from human exfoliated deciduous teeth (SHED) is simple and convenient, with little or no trauma. Every child loses primary teeth, which creates the perfect opportunity to recover and store this convenient source of stem cells--should they be needed to treat future injuries or ailments and presents a far better alternative to simply discarding the teeth or storing them as mementos from the past. Furthermore, using ones own stem cells poses few, if any, risks for developing immune reactions or rejection following transplantation and also eliminates the potential of contracting disease from donor cells. Stem cells can also be recovered from developing wisdom teeth and permanent teeth. Individuals have different opportunities at different stages of their life to bank these valuable cells. It is best to recover stem cells when a child is young and healthy and the cells are strong and proliferative. The purpose of this review is to discuss the present scenario as well as the technical details of tooth banking as related to SHED cells.

  13. Permanent molar pulpotomy with a new endodontic cement: A case series

    PubMed Central

    Asgary, Saeed; Ehsani, Sara

    2009-01-01

    The aim of this case series was to determine the clinical and radiographic success rate of pulpotomy, with new endodontic cement (NEC), in human mature permanent molar teeth. Twelve molars with established irreversible pulpitis were selected from patients 14 – 62 years old. The selection criteria included carious pulp exposure with a positive history of lingering pain. After isolation, caries removal, and pulp exposure, pulpotomy with NEC was performed and a permanent restoration was immediately placed. At the first recall (+1 day) no patients reported postoperative pain. One wisdom tooth had been extracted after two months because of failure in coronal restoration. Eleven patients were available for the second recall, with a mean time of 15.8 months. Clinical and radiographic examination revealed that all teeth were functional and free of signs and symptoms. Histological examination of the extracted teeth revealed complete dentin bridge formation and a normal pulp. Although the results favored the use of NEC, more studies with larger samples and a longer recall period were suggested, to justify the use of this novel material for treatment of irreversible pulpitis in human permanent molar teeth. PMID:20379438

  14. An alternative impression technique for mobile teeth.

    PubMed

    Lampraki, Evangelia; Chochlidakis, Konstantinos M; Rossopoulos, Evangelos; Ercoli, Carlo

    2016-10-01

    The impression technique described combines elastomeric impression materials and irreversible hydrocolloid to make an accurate preliminary impression of extremely mobile and misaligned teeth. Upon setting, the materials are removed from the mouth in 3 different directions and reassembled extraorally. This technique provides an alternative, easy, accurate, and safe way to make a preliminary impression of mobile, periodontally involved teeth.

  15. 21 CFR 872.5550 - Teething ring.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Teething ring. 872.5550 Section 872.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... divice intended for use by infants for medical purposes to soothe gums during the teething process....

  16. Disinfection of Human Teeth for Educational Purposes.

    ERIC Educational Resources Information Center

    Tate, William H.; White, Robert S.

    1991-01-01

    A study investigated the efficacy of glutaraldehyde and several other disinfectants for disinfecting teeth to be used for teaching and research, as an alternative to autoclaving for teeth with amalgam restorations. Results indicate that formalin was the only disinfectant that penetrated tooth pulp chambers in effective antimicrobial…

  17. Transplantation of Cryopreserved Teeth: A Systematic Review

    PubMed Central

    Osathanon, Thanaphum

    2010-01-01

    The aim of this article was to examine the research articles regarding biological and mechanical properties of cryopreserved teeth for potential use in tooth transplantation. A systematic review of literatures was performed by Pubmed searching with assigned key words from January 1, 1990 to June 8, 2009. All articles were examined for inclusion criteria. Secondary search was conducted by hand-search through references of included articles from primary search. A total of 24 articles were obtained from both primary and secondary search and used as fundamental articles in this review. Periodontal ligament tissues of cryopreserved teeth were able to maintain their biological properties resulted in a satisfactory healing of periodontium. Dental pulp tissues, however, may be compromised by limitation of permeability of cryopreservative agent into pulp cavity. Therefore, an endodontic treatment of transplanted cryopreserved teeth was recommended. Cryopreserved teeth had comparable mechanical properties to those of normal teeth. Importantly, the success of cryopreserved tooth transplantation treatment in orthodontic patients was reported. The cryopreserved teeth for tooth banking have a potential clinical application for treatment of missing teeth. Case selection, however, is critical for treatment success. More studies and data regarding masticatory function and periodontal healing of transplanted cryopreserved teeth are needed. PMID:20737931

  18. Loss of Permanent First Molars in the Mixed Dentition: Circumstances Resulting in Extraction and Requiring Orthodontic Management.

    PubMed

    Mathu-Muju, Kavita R; Kennedy, David B

    2016-10-15

    Extraction of significantly compromised permanent first molars may be indicated during the mixed dentition stage of occlusal development. The purpose of this article was to review circumstances that can result in the loss of a permanent first molar-including dental caries, molar incisor hypomineralization, eruption disturbances of permanent teeth, and failure of restorative treatment to affirm that a complete dental arch is not necessary for the existence of a functional dental arch. The extraction of permanent first molar(s) with subsequent orthodontic treatment in a young patient can be considered a cost-effective alternative to placing complex restorations that require replacement over the lifespan. Approaches to establish a functional dental arch in the event of the loss of a permanent first molar(s) are outlined. Additionally, orthodontic diagnostic and treatment principles are reviewed. Case histories are provided to illustrate the clinical management of permanent first molar extractions to achieve a functional dental arch.

  19. The prevalence and treatment of dental caries among Israeli permanent force military personnel.

    PubMed

    Sgan-Cohen, H D; Horev, T; Zusman, S P; Katz, J; Eldad, A

    1999-08-01

    A survey was conducted to determine dental caries prevalence and treatment among 1,095 25- to 44-year-old permanent force Israeli military personnel. Caries experience, by decayed, missing, and filled permanent teeth (DMFT), was 11.66, with an average of 1.37 untreated caries, 2.40 extracted teeth, and 7.90 treated teeth. Caries was positively associated with age (p < 0.001). Females demonstrated statistically higher DMFT levels than males (p = 0.009). Negative associations were detected for education levels and untreated and extracted components (p < 0.001), and a positive association was detected for the treated caries component (p < 0.001). Permanent military personnel treated by private dentists exhibited 17.6% untreated caries, compared with 9.4% among personnel treated in the army. Officers had lower levels of untreated caries (8.6%) than others (13.3%). Among the present population, 77% had attended a dental clinic in the preceding 2 years. Permanent force personnel are offered free, comprehensive, and accessible dental treatment. The data emphasize a need for further dental health education.

  20. Achieving permanency for LGBTQ youth.

    PubMed

    Jacobs, Jill; Freundlich, Madelyn

    2006-01-01

    This article brings together two significant efforts in the child welfare field: achieving permanence for youth in out-of-home care and meeting the needs of lesbian, gay, bisexual, transgender and questioning (LGBTQ) youth. During the past several years, a national movement has taken place to assure all children and youth have a permanent family connection before leaving the child welfare system; however, LGBTQ youth are not routinely included in the permanency discussions. At the same time, efforts in addressing the needs of LGBTQ youth have increased, but permanency is rarely mentioned as a need. This article offers models of permanence and practices to facilitate permanence with LGBTQ youth and their families. It also offers a youth-driven, individualized process, using youth development principles to achieve relational, physical, and legal permanence. Reunification efforts are discussed, including services, supports, and education required for youth to return to their family of origin. For those who cannot return home, other family resources are explored. The article also discusses cultural issues as they affect permanence for LGBTQ youth, and, finally, addresses the need for ongoing support services to sustain and support permanency.

  1. Primary retention of first permanent mandibular molars in 29 subjects.

    PubMed

    Nielsen, Signe Hauberg; Becktor, Karin Binner; Kjaer, Inger

    2006-12-01

    This study consisted of two parts: the first part describes the aetiology behind primary retention of first permanent mandibular molars by comparing the affected molar region with the contralateral region, and the second the follow-up of the retained molars. The material comprised dental pantomograms from 29 patients (17 males and 12 females; aged 6 years 2 months to 12 years 5 months) which were sent by Danish public dental clinics to the Department of Orthodontics at Copenhagen Dental School for treatment guidance (Part 1). Questionnaires were later sent to the dentists for follow-up information regarding the affected teeth (Part 2). Part 1-aetiological evaluation: From each radiograph, the number and location of the molars, maturity of individual molars, and deviations from normal morphology were recorded. The findings showed that, in an affected region, disruption of normal dental development and eruption had occurred, causing a delay in dental maturity as well as arrested eruption of the first molar. Part 2-follow-up of eruption: Completed questionnaires and radiographs were returned for 25 subjects. In 10, eruption had occurred, six after surgical removal of mucosa covering the retained first molar. In eight patients the molar had been removed while in seven the observation time from first diagnosis was too short to evaluate eruption. The results indicate that retained first permanent mandibular molars have the ability to erupt and suggest that a unilaterally retained first permanent mandibular molar may represent a temporary delay in eruption rather than permanent failure.

  2. Orthodontics Align Crooked Teeth and Boost Self-Esteem

    MedlinePlus

    ... desktop! more... Orthodontics Align Crooked Teeth and Boost Self- esteem Article Chapters Orthodontics Align Crooked Teeth and Boost Self- esteem Orthodontics print full article print this chapter email ...

  3. Romundina and the evolutionary origin of teeth

    PubMed Central

    Rücklin, Martin; Donoghue, Philip C. J.

    2015-01-01

    Theories on the origin of vertebrate teeth have long focused on chondrichthyans as reflecting a primitive condition—but this is better informed by the extinct placoderms, which constitute a sister clade or grade to the living gnathostomes. Here, we show that ‘supragnathal’ toothplates from the acanthothoracid placoderm Romundina stellina comprise multi-cuspid teeth, each composed of an enameloid cap and core of dentine. These were added sequentially, approximately circumferentially, about a pioneer tooth. Teeth are bound to a bony plate that grew with the addition of marginal teeth. Homologous toothplates in arthrodire placoderms exhibit a more ordered arrangement of teeth that lack enameloid, but their organization into a gnathal, bound by layers of cellular bone associated with the addition of each successional tooth, is the same. The presence of enameloid in the teeth of Romundina suggests that it has been lost in other placoderms. Its covariation in the teeth and dermal skeleton of placoderms suggests a lack of independence early in the evolution of jawed vertebrates. It also appears that the dentition—manifest as discrete gnathal ossifications—was developmentally discrete from the jaws during this formative episode of vertebrate evolution. PMID:26109615

  4. 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.

  5. Permanent-Magnet Meissner Bearing

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  6. Agenesis of Multiple Primary Teeth and

    PubMed Central

    Gokhale, Niraj; Sivakumar, N; Quadar, Md Akhil

    2013-01-01

    ABSTRACT Agenesis of multiple primary teeth is rare. A 6-year-old girl visited our department, in the absence of any other systemic abnormalities, on clinical and radiographic evaluation, it was revealed that she had only 6 primary teeth in her mouth. Maxillary and mandibular removable partial dentures were fabricated for prosthodontic rehabilitation. At the 6 months follow-up nutrition of the patient as well as self-confident appearance was improved. How to cite this article: Nirmala SVSG, Gokhale N, Sivakumar N, Quadar MA. Agenesis of Multiple Primary Teeth and Its Rehabilitation: A Case Report. Int J Clin Pediatr Dent 2013; 6(1):55-57. PMID:25206190

  7. Rugometric and microtopographic inspection of teeth enamel

    NASA Astrophysics Data System (ADS)

    Costa, Manuel F.; Pereira, Pedro B.

    2013-06-01

    The roughness of teeth' enamel is an important parameter in orthodontics. One example is the application in the process of decreasing tooth-size by reducing the interproximal enamel surfaces (stripping) of teeth. In order to achieve smooth surfaces clinicians have been testing various methods and progressively improved this therapeutic technique. The evaluation the surface roughness following teeth interproximal reduction is fundamental in the process. In general tooth' surface is not flat presenting a variety of complex geometries. In this communication we will report on the metrological procedure employed on the rugometric and microtopographic inspection by optical active triangulation of raw and processed (interproximal stripping) tooth surfaces.

  8. MTA pulpotomy of human permanent molars with irreversible pulpitis.

    PubMed

    Eghbal, Mohammad Jafar; Asgary, Saeed; Baglue, Reza Ali; Parirokh, Masoud; Ghoddusi, Jamileh

    2009-04-01

    The histological success of mineral trioxide aggregate (MTA) pulpotomy for treatment of irreversible pulpitis in human teeth as an alternative treatment was investigated in this study. Fourteen molars which had to be extracted were selected from patients 16-28 years old. The selection criteria include carious pulp exposure with a history of lingering pain. After isolation, caries removal and pulp exposure, MTA was used in pulpotomy treatment. Patients were evaluated for pain after 24 h. Two patients were lost from this study. Twelve teeth were extracted after 2 months and were assessed histologically. Recall examinations confirmed that none of the patients experienced pain after pulpotomy. Histological observation revealed that all samples had dentin bridge formation completely and that the pulps were vital and free of inflammation. Although the results favour the use of MTA as a pulpotomy material, more studies with larger samples and a longer recall period are suggested to justify the use of MTA for treatment of irreversible pulpitis in human permanent teeth.

  9. Diagnosis and Management of a Patient with Congenitally Missing Maxillary First Permanent Molars: A Rare Case Report

    PubMed Central

    Panda, Suman; Kariri, Fahad Musawi Mohammed

    2016-01-01

    Congenitally missing teeth are the most commonly seen dental anomalies. Agenesis of the permanent first molar has the least frequency of all the tooth types, and it usually occurs in association with oligodontia or anodontia. Thus, agenesis of the bilateral maxillary first permanent molar is an extremely rare occurrence, and no such case has been reported in ethnic Saudi Arabian population. We hereby report a case of nonsyndromic bilateral congenitally missing maxillary first permanent molar in an eight-year-old Saudi female patient. Comprehensive oral rehabilitation was done for the patient. The implications of the tooth agenesis are also discussed. The prognosis of this case is presented. PMID:27525130

  10. Nonsurgical endodontic retreatment of fused teeth with transposition: a case report

    PubMed Central

    Noites, Rita Brandão; Martins, Miguel André Duarte; Paulo, Manuel Pedro da Fonseca

    2016-01-01

    Tooth transposition is a disorder in which a permanent tooth develops and erupts in the normal position of another permanent tooth. Fusion and gemination are developmental disturbances presenting as the union of teeth. This article reports the nonsurgical retreatment of a very rare case of fused teeth with transposition. A patient was referred for endodontic treatment of her maxillary left first molar in the position of the first premolar, which was adjacent to it on the distobuccal side. Orthopantomography and periapical radiography showed two crowns sharing the same root, with a root canal treatment and an associated periapical lesion. Tooth fusion with transposition of a maxillary molar and a premolar was diagnosed. Nonsurgical endodontic retreatment was performed. At four yr follow-up, the tooth was asymptomatic and the radiolucency around the apical region had decreased, showing the success of our intervention. The diagnosis and treatment of fused teeth require special attention. The canal system should be carefully explored to obtain a full understanding of the anatomy, allowing it to be fully cleaned and obturated. Thermoplastic techniques were useful in obtaining hermetic obturation. A correct anatomical evaluation improves the set of treatment options under consideration, leading to a higher likelihood of esthetically and functionally successful treatment. PMID:27200284

  11. Take Care of Your Teeth and Gums

    MedlinePlus

    ... En español Take Care of Your Teeth and Gums Browse Sections The Basics Overview Take Action! Brushing ... only in moderation. What causes tooth decay and gum disease? Plaque (“plak”) is a sticky substance that ...

  12. [A Rare Case of Neonatal Teeth].

    PubMed

    Martins, Andreia A; Ferraz, Cláudia; Vaz, Rute

    2015-01-01

    Neonatal teeth is a rare disorder of tooth eruption, arising in the oral cavity, usually in the anterior mandible, in the first month of life. Its etiology is unknown. This condition can cause breastfeeding difficulties, besides aspiration or swallowing of the teeth. We describe the case of a premature infant in the second day of life presented with gingival edema, redness and discrete swelling in the region of the mandibular central incisors. Ten days later, two small teeth with hypermobility were detected. Extraction of those teeth was performed. With this clinical case we intend to show the rarity of this entity, especially in premature infants, the possible association with various syndromes and the need for a multifactorial approach to the treatment decision (extraction / conservative treatment).

  13. Bruxism (Teeth Grinding or Clenching) (For Parents)

    MedlinePlus

    ... to other family members because of the grinding sound. In some cases, nighttime grinding and clenching can wear down tooth enamel, chip teeth, increase temperature sensitivity, and cause severe facial pain and jaw ...

  14. 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.

  15. 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.

  16. The etch-bleach-seal technique for managing stained enamel defects in young permanent incisors.

    PubMed

    Wright, J Timothy

    2002-01-01

    Hypomineralized enamel defects frequently are manifest as a mottled-white appearance and can be associated with variable degrees of discrete yellow-brown intrinsic staining. Numerous treatment approaches have been proposed, ranging from bleaching to enamel reduction to restorative techniques. Bleaching of hypomineralized enamel lesions, using 1 to 2 applications (10 to 15 minutes each) of 5% sodium hypochlorite, has been applied clinically. Treatment using this approach has proven successful in removing yellow-brown discolorations from lesions in young permanent teeth. Young permanent incisors with yellow-brown intrinsic discolorations can often be treated by a simple and conservative bleaching protocol using sodium hypochlorite.

  17. Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation.

    PubMed

    Hernandéz-Gatón, Patrícia; Serrano, César Ruiz; Nelson Filho, Paulo; De Castañeda, Esther Ruiz; Lucisano, Marília P; Silva, Raquel A B da; Silva, Léa A B da

    2015-01-01

    This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis.

  18. Prevalence of prematurely lost primary teeth in 5–10-year-old children in Thamar city, Yemen: A cross-sectional study

    PubMed Central

    Murshid, Sakhr A.; Al-Labani, Mohammed A.; Aldhorae, Khalid A.; Rodis, Omar M. M.

    2016-01-01

    Objectives: The premature loss of primary teeth is a potential risk factor for poor arch length development. Adequate arch length is important to the progression of the permanent teeth. Poor arch length can lead to crowding, ectopic eruption, or impaction of these teeth. This study is designed to assess the prevalence of premature loss of primary teeth in the 5-10-year-old age group. Materials and Methods: The study group included 185 children, that is, 91 boys and 94 girls. The dental examination was conducted by an experienced examiner under sufficient artificial light. Data including patient age and missing teeth were collected. Descriptive statistics were applied for data analysis, and from the results, Chi-square tests were used at a level of significance of 5% (P < 0.05). Results: We observed a 40.54% prevalence of premature loss of primary teeth with no statistically significant difference between genders. The lower left primary second molar was the most commonly absent tooth in the dental arch (13.5%). Conclusion: The status of premature loss of primary teeth was high in the study group. Implementation of efficient educational and preventive programs to promote oral health would help children maintain a healthy primary dentition and eventually prevent the disturbances in the future development of normal occlusion. Early detection and management of the space problems associated with the early loss of primary teeth would help in reducing malocclusion problems. PMID:27652244

  19. Reestablishing the Function and Esthetics in Traumatized Permanent Teeth with Large Apical Lesion

    PubMed Central

    Cocco, Alexandra Rubin; Bobrowski, Ângelo Niemczewski; Baldissera, Rudimar Antônio; Machado Silveira, Luiz Fernando

    2016-01-01

    Dental trauma is a challenge for dental integrity and can lead to pulp necrosis. The clinical case reports the diagnosis of a maxillary right central incisor traumatized and its multidisciplinary treatment. Calcium hydroxide material was used to perform the processing apexification. An apical surgery was carried out to remove the apical periodontitis and to return the aesthetics to the patient; internal and external tooth whitening in maxillary right central incisor was performed. We conclude that surgery associated with the root filling in the central incisor led to a successful completion. Moreover, it is of utmost importance to demonstrate the interaction between the various areas of dentistry. PMID:28078147

  20. Background factors affecting dental caries in permanent teeth of Finnish and Soviet children.

    PubMed

    Honkala, E; Kolmakow, S; Nyyssönen, V; Kuzmina, E; Vasina, S

    1992-01-01

    The aim of this study was to analyze the association between some general background factors and caries experience in two groups of Finnish children (from Helsinki and Kuopio) and Soviet children (Moscow and Leningrad). A total of 1187 schoolchildren, ages seven, nine and twelve years, were examined and information about their health habits was gathered by questionnaire. Questions included use of sweets, cakes, soft drinks, sugar-sweetened coffee and tea, toothbrushing frequency and mother's education. Except for age, the factors that explain caries experience clearly differ in Finnish and Soviet children.

  1. 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

  2. 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.

  3. Straight, white teeth as a social prerogative.

    PubMed

    Khalid, Abeer; Quiñonez, Carlos

    2015-06-01

    A distinguishing feature of North American society is preoccupation with self-image, as seen in the ritualistic nature of bodily practices aimed at constantly improving the body. Nowhere is this more apparent than in the prevailing fixation with straight, white teeth. While there is an ever-expanding literature on the sociology of body, very little has been written on teeth in this context. Using literature from anthropology, biology, dentistry, sociology and social psychology, this study attempts to answer: (1) Why have straight, white teeth become a beauty ideal in North American society? (2) What is the basis for this ideal? (3) How is this ideal propagated? It demonstrates that dental aesthetic tendencies are biologically, culturally and socially patterned. Concepts from the works of Pierre Bourdieu and Michel Foucault are used to illustrate how straight, white teeth contribute towards reinforcing class differences and how society exercises a disciplinary power on individuals through this ideal. It is concluded that modified teeth are linked to self and identity that are rooted in social structure. Moreover, teeth demonstrate the ways in which class differences are embodied and projected as symbols of social advantage or disadvantage. Implications on professional, public health, sociological and political levels are considered.

  4. Apexogenesis and revascularization treatment procedures for two traumatized immature permanent maxillary incisors: a case report.

    PubMed

    Forghani, Maryam; Parisay, Iman; Maghsoudlou, Amir

    2013-08-01

    Traumatic injuries to an immature permanent tooth may result in cessation of dentin deposition and root maturation. Endodontic treatment is often complicated in premature tooth with an uncertain prognosis. This article describes successful treatment of two traumatized maxillary central incisors with complicated crown fracture three months after trauma. The radiographic examination showed immature roots in maxillary central incisors of a 9-year-old boy with a radiolucent lesion adjacent to the right central incisor. Apexogenesis was performed for the left central incisor and revascularization treatment was considered for the right one. In 18-month clinical and radiographic follow-up both teeth were asymptomatic, roots continued to develop, and periapical radiolucency of the right central incisor healed. Considering the root development of these contralateral teeth it can be concluded that revascularization is an appropriate treatment method in immature necrotic teeth.

  5. Apexogenesis and revascularization treatment procedures for two traumatized immature permanent maxillary incisors: a case report

    PubMed Central

    Forghani, Maryam; Maghsoudlou, Amir

    2013-01-01

    Traumatic injuries to an immature permanent tooth may result in cessation of dentin deposition and root maturation. Endodontic treatment is often complicated in premature tooth with an uncertain prognosis. This article describes successful treatment of two traumatized maxillary central incisors with complicated crown fracture three months after trauma. The radiographic examination showed immature roots in maxillary central incisors of a 9-year-old boy with a radiolucent lesion adjacent to the right central incisor. Apexogenesis was performed for the left central incisor and revascularization treatment was considered for the right one. In 18-month clinical and radiographic follow-up both teeth were asymptomatic, roots continued to develop, and periapical radiolucency of the right central incisor healed. Considering the root development of these contralateral teeth it can be concluded that revascularization is an appropriate treatment method in immature necrotic teeth. PMID:24010086

  6. [Prevalence of first permanent molar loss in 6 to 12-year-old students of both sexes in Ribeirão Preto].

    PubMed

    Ferlin, L H; Daruge, A D; Daruge, R J; Rancan, S V

    1989-01-01

    The authors study the prevalence of lost of the first permanent molars in 6 to 12 years old schoolchildren of medium and low social-economic levels, in both sexes, from Ribeirão Preto, SP., on right and left hemiarcs, and both maxilars. The results indicate that teeth los was significantly higher in females, and in both sexes the teeth lost was higher in the lower maxilar. No differences were also observed between hemiarchs.

  7. Periodic permanent magnet focused klystron

    DOEpatents

    Ferguson, Patrick; Read, Michael; Ives, R Lawrence

    2015-04-21

    A periodic permanent magnet (PPM) klystron has beam transport structures and RF cavity structures, each of which has permanent magnets placed substantially equidistant from a beam tunnel formed about the central axis, and which are also outside the extent of a cooling chamber. The RF cavity sections also have permanent magnets which are placed substantially equidistant from the beam tunnel, but which include an RF cavity coupling to the beam tunnel for enhancement of RF carried by an electron beam in the beam tunnel.

  8. Autotransplantation of Ectopic Permanent Maxillary Incisors

    PubMed Central

    Abd Jalil, Laila; Muhd Noor, Nurhidayah

    2017-01-01

    The report presents examples of successful cases of autotransplantation of ectopic teeth as donor in the treatment of clinically missing maxillary anterior teeth in young patients. The transplanted teeth were either severely ectopic, inverted, rotated or in an unfavourable position that they are commonly sacrificed as a result. Details of surgical technique as well as clinical and radiographic assessments were discussed. PMID:28352481

  9. Ferric sulfate as pulpotomy agent in primary teeth: twenty month clinical follow-up.

    PubMed

    Ibricevic, H; al-Jame, Q

    2000-01-01

    Seventy primary molar teeth, carious exposed, symptom free, without any sign of root resorption in children aged from 3 to 6 years (main age 4.3 yr) were treated with conventional pulpotomy procedures. Ferric sulfate 15.5% solution (applied for 15 second for 35 teeth) and formocresol solution (five minute procedure of Buckley's formula for next 35 teeth) have been used as pulpotomy agents. In both groups, pulp stumps were covered with zinc-oxide eugenol paste. Permanent restorations were stainless steel crowns. Clinical check up was every three-months and radiographic follow-up time was six and twenty months after treatment. Our results within this period revealed 100% clinical success rate in both groups. Radiographic success rate was in both groups 97.2%, while in 2.8% cases has shown internal root resorption. On the basis of these results, we can recommend ferric sulfate as a pulpotomy agent in primary teeth in substitution for formocresol at the moment.

  10. Computer-assisted intraosseous anaesthesia for molar and incisor hypomineralisation teeth. A preliminary study.

    PubMed

    Cabasse, C; Marie-Cousin, A; Huet, A; Sixou, J L

    2015-03-01

    Anesthetizing MIH (Molar and Incisor Hypomineralisation) teeth is one of the major challenges in paediatric dentistry. Computer-assisted IO injection (CAIO) of 4% articaine with 1:200,000 epinephrine (Alphacaine, Septodont) has been shown to be an efficient way to anesthetize teeth in children. The aim of this study was to assess the efficacy of this method with MIH teeth. This preliminary study was performed using the Quick Sleeper system (Dental Hi Tec, Cholet, France) that allows computer-controlled rotation of the needle to penetrate the bone and computer-controlled injection of the anaesthetic solution. Patients (39) of the department of Paediatric Dentistry were included allowing 46 sessions (including 32 mandibular first permanent molars) to be assessed. CAIO showed efficacy in 93.5% (43/46) of cases. Failures (3) were due to impossibility to reach the spongy bone (1) and to achieve anaesthesia (2). This prospective study confirms that CAIO anaesthesia is a promising method to anesthetize teeth with MIH that could therefore be routinely used by trained practitioners.

  11. Maxillary versus mandibular arch form differences in human permanent dentition assessed by Euclidean-distance matrix analysis.

    PubMed

    Ferrario, V F; Sforza, C; Miani, A; Tartaglia, G

    1994-02-01

    Euclidean-distance matrix analysis (EDMA) was used to analyse the dental arch form in 50 men and 45 women aged 20-27 yr with sound dentitions. Fourteen landmarks, corresponding to the centres of gravity (centroids) of the occlusal surfaces of all permanent teeth (right second molar to left second molar), were identified on the dental casts of subjects. All the possible linear distances between pairs of teeth were computed and maxillary/mandibular arch differences within sex were tested by EDMA. In both sexes, the maxillary arch was larger than the mandibular arch; arch shape was also significantly different. All teeth contributed to the shape difference between arches regardless of gender. EDMA also separated the influence of anterior and posterior teeth in the determination of upper/lower arch characteristics.

  12. [Furcation lesions in deciduous teeth].

    PubMed

    Demars-Fremault, C; Pilipili Muhima, C

    1991-03-01

    The area of furcation of temporary molars constitutes a zone of exchanges and rearrangements relating to the evolution of the sub-adjacent permanent tooth. It is subjected to the eruption of the latter and to the physiological modifications of the temporary tooth. Moreover, this area is the site of above-mentioned inflammatory or infections conditions, maintained or aggravated by anatomical factors (accessory canals, thin pulpar floor, with little calcified dentine and broad tubuli), physiological factors (multiplication of accessory canals, decrease in the floor and migration of the epithelial attachment), endodontic factors (pulpal involvement and its complications) and periodontal factors (septum syndrome). The pathology of furcation is an evolving lesion. When discovered early it can be treated by endodontic therapy, while, in a later phase, it will require the extraction of the tooth. The assessment is made on the basis of a X-Ray examination which permits the temporary tooth to be situated in its stable or labile phase, the condition of the pulpal floor to be evaluated and the stage of sub-adjacent germ mineralisation to be estimated. A periodontal arrangement, by coronal reconstitution, conditions the reliability of the endodontic therapies.

  13. Parsonage-Turner syndrome associated with anti-bovine viral diarrhoea virus antibodies.

    PubMed

    Giangaspero, M; Cominardi, P F

    2006-01-01

    The Parsonage-Turner syndrome, a rare form of neuralgic amyotrophy of unknown aetiology, was diagnosed in a patient involved in an outbreak of bovine viral diarrhoea virus (BVDV). The patient, suffering from inflammation of the right shoulder with a permanent atrophy, developed anti-BVDV antibody titres which remained very high during the four following years of monitoring.

  14. The effect of a partial bite-raising splint on the inclination of upper and lower front teeth.

    PubMed

    Dahl, B L; Krogstad, O

    1983-10-01

    In a previous paper it was maintained that the effect of the permanent use of an anterior partial bite-raising splint was an intrusion of the front teeth and an eruption of the others. However, the effect might have been merely a change in the inclination of the front teeth. The present study comprised the same material as earlier. Linear and angular changes in the position of upper and lower incisors were measured on cephalometric radiographs. In the upper jaw a possible average proclination occurred, whereas in the lower jaw no or only a very small retroclination took place. The values were well within the method error, and it was concluded that the effect of the splint had been one of intrusion of the upper and lower front teeth and not merely a change in their inclination.

  15. Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment

    PubMed Central

    Rakhshan, Vahid

    2015-01-01

    Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insufficient alveolar bone growth, reduced chewing ability, inarticulate pronunciation and other problems. Treatment might be usually expensive and multidisciplinary. This highly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fields such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacial surgery, anatomy, anthropology and even the insurance industry. This essay reviews the findings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible. PMID:25709668

  16. Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment.

    PubMed

    Rakhshan, Vahid

    2015-01-01

    Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insufficient alveolar bone growth, reduced chewing ability, inarticulate pronunciation and other problems. Treatment might be usually expensive and multidisciplinary. This highly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fields such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacial surgery, anatomy, anthropology and even the insurance industry. This essay reviews the findings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible.

  17. Orthodontic treatment of impacted anterior teeth due to odontomas: a report of two cases.

    PubMed

    Batra, Puneet; Duggal, Ritu; Kharbanda, Om Prakash; Parkash, Hari

    2004-01-01

    Two cases are presented where the odontomas had caused the impaction of the anterior teeth and required a combined surgical and orthodontic treatment to bring these teeth into the arch. In the first case a large a complex odontome had caused the impaction of the right central incisor, lateral incisor and canine. In the second case a compound odontome blocked the eruption pathway of the right central incisor. It is emphasised that radiographic examination of all pediatric patients that present clinical evidence of delayed permanent tooth eruption or temporary tooth displacement with or without a history of previous dental trauma should be performed. Early diagnosis of odontomas allows adoption of a less complex and less expensive treatment and ensures a better prognosis.

  18. Fatigue resistance of teeth restored with fiber posts and different post cementation strengths.

    PubMed

    Valandro, Luiz Felipe; Zardin, Lucas Wadas; de Villa, Marco Antonio; Amaral, Marina; Galhano, Graziela; Baldissara, Paolo; Bottino, Marco Antonio

    2009-01-01

    This study sought to evaluate how different post cementation strategies affected the fatigue resistance of bovine teeth restored with glass fiber posts. The canals of 63 single-rooted bovine teeth (each 16 mm in length) were prepared to 9 mm using a preparation drill from a double-tapered fiber post system. Each specimen was embedded in a PVC cylinder using acrylic resin up to 3 mm of the most coronal portion of the specimen and was allocated into one of seven groups (n = 9) based on the strategies for cementation. After cementation, a standard core build-up was made with composite resin. The specimens were stored for seven days and submitted to mechanical cycling (50 N, 8 Hz, 37 degrees C). After fatigue testing, a score was given to each specimen, based on the number of fatigue cycles required to fracture the specimens; the scores were submitted to statistic analysis (Kruskal-Wallis, alpha = 0.05). The strategy for post cementation did not affect the resistance to fatigue (P = 0.8669). Based on the results, the resistance to fatigue does not appear to depend on the post cementation strategy.

  19. Forensic identification in teeth with caries.

    PubMed

    Alia-García, Esther; Parra-Pecharromán, David; Sánchez-Díaz, Ana; Mendez, Susy; Royuela, Ana; Gil-Alberdi, Laura; López-Palafox, Juan; del Campo, Rosa

    2015-12-01

    Human teeth are biological structures that resist extreme conditions thus becoming a useful source of DNA for human forensic identification purposes. When it is possible, forensic prefer only non-damaged teeth whereas those with cavities are usually rejected to avoid both external and internal bacterial contamination. Cavities are one of the most prevalent dental pathology and its incidence increases with ageing. The aim of this study was to validate the use of teeth with cavities for forensic identification. A total of 120 individual teeth from unrelated patients (60 healthy and 60 with cavities, respectively) extracted by a dentist as part of the normal process of treatment, were submitted for further analysis. Dental pulp was obtained after tooth fragmentation, complete DNA was extracted and the corresponding human identification profile was obtained by the AmpFlSTR® NGM SElect™ kit. Cariogenic microbiota was determined by PCR-DGGE with bacterial universal primers and bands were excised, re-amplified and sequenced. From the 120 dental pieces analyzed, a defined genetic profile was obtained in 81 (67.5%) of them, with no statistical differences between the healthy and the cavities-affected teeth. Statistical association between teeth status, DNA content and genetic profiles was not observed. Complex bacterial communities were only detected in the cavities group, being the Streptococcus/Enterococcus, and Lactobacillus genera the most represented. We conclude that teeth with cavities are as valid as healthy dental pieces for forensic human identification. Moreover, the severity of the cariogenic lesion as well as associated bacterial communities seems not to influence the establishment of human dental profiles.

  20. Bovine milk exosome proteome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exosomes are 40-100 nm membrane vesicles of endocytic origin and are found in blood, urine, amniotic fluid, bronchoalveolar lavage (BAL) fluid, as well as human and bovine milk. Exosomes are extracellular organelles important in intracellular communication/signaling, immune function, and biomarkers ...

  1. Bovine Spongiform Encephalopathy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine spongiform encephalopathy (BSE), also referred to as “mad cow disease” is a chronic, non-febrile, neuro-degenerative disease affecting the central nervous system. The transmissible spongiform encephalopathies (TSEs) of domestic animals, of which BSE is a member includes scrapie of sheep...

  2. Bovine Spongiform Encephalopathy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine spongiform encephalopathy (BSE) is caused by a novel contagion, known to as a prion. Prions are proteins capable of converting a normal cellular protein into a prion, thereby propagating an infection. BSE is the first known prion zoonotic. As such it has attracted broad scientific and, to a r...

  3. Protein Crystal Bovine Insulin

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The comparison of protein crystal, Bovine Insulin space-grown (left) and earth-grown (right). Facilitates the incorporation of glucose into cells. In diabetics, there is either a decrease in or complete lack of insulin, thereby leading to several harmful complications. Principal Investigator is Larry DeLucas.

  4. Genotyping bovine coronaviruses.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine coronaviruses (BoCV) are enveloped, single-stranded, positive-sense RNA viruses of the Coronaviridae family. Infection is associated with enteritis and pneumonia in calves and Winter Dysentery in adult cattle. Strains, isolated more than 50 years ago, are used in vaccines and as laboratory ...

  5. Effects of PAX9 and MSX1 gene variants to hypodontia, tooth size and the type of congenitally missing teeth.

    PubMed

    Kirac, D; Eraydin, F; Avcilar, T; Ulucan, K; Özdemir, F; Guney, A I; Kaspar, E Ç; Keshi, E; Isbir, T

    2016-11-30

    ooth agenesis, affecting up to 20% of human population, is one of the most common congenital disorder. The most frequent form of tooth agenesis is known as hypodontia, which is characterized by the absence of one to five permanent teeth excluding third molars. It was considered that hypodontia is especially related with gene mutations which play role in tooth formation. Additionally mutations in PAX9 and/or MSX1 have been identified as the defects responsible for missing permanent molars and second premolars. In some studies it was also found that PAX9 and MSX1 gene mutations may change tooth size. Therefore  in this study all of these factors were investigated. Thirty one patients and 30 controls were enrolled to the study. Information about tooth sizes and type of congenitally missing teeth were collected. MSX1 and PAX9 gene mutations were investigated by direct sequencing. Results were evaluated statistically. As a result, 22 variations were detected in PAX9 in which 18 of them are novel. In addition, 7 variations were found in MSX1 in which 5 of them are novel and one of them lead to amino acid change. Statistically significant relations were found between detected variations and tooth sizes. Any relation between mutations and type of congenitally missing teeth were not detected. In conclusion, especially new mutations which may cause hypodontia, effect tooth size and type of congenitally missing teeth, should be investigated with other researchers for clarifying the mechanism.

  6. Efficacy of enamel matrix derivatives (Emdogain) in treatment of replanted teeth--a systematic review based on animal studies.

    PubMed

    Wiegand, Annette; Attin, Thomas

    2008-10-01

    The objective of the current systematic review was to evaluate the efficacy of enamel matrix derivative (EMD) (Emdogain) on healing of replanted or autotransplanted permanent teeth. A review of the published literature [search term: (Emdogain OR enamel matrix derivative OR enamel matrix protein] AND [avulsion OR replantation OR autotransplantation)] was conducted by two independent investigators according to defined selection criteria. For data extraction of the identified animal studies, the following histomorphometric findings were considered: (i) healed PDL, (ii) surface resorption, (iii) inflammatory resorption and (iv) replacement resorption. The heterogeneity of data collection and the small amount of identified publications did not allow for statistical analysis. Four controlled trials (CT) conducted in animals, but no randomized controlled trials (RCT) or clinical controlled trials (CCT) could be received from the systematic search. From the selected studies, two CT gave evidence of EMD treatment to be effective in inducing healing of replanted teeth, while one CT found no differences between EMD treated teeth and controls. Finally, one CT compared EMD and sodium fluoride application, but revealed no differences between the treatments. The data of controlled trials available are limited and conflicting. No firm conclusion regarding the efficacy of EMD application on healing of replanted or autotransplanted permanent teeth can be drawn because of lack of RCT and CCT.

  7. Solid modeling of fossil small mammal teeth

    NASA Astrophysics Data System (ADS)

    Marschallinger, Robert; Hofmann, Peter; Daxner-Höck, Gudrun; Ketcham, Richard A.

    2011-09-01

    This paper presents an approach to create solid models of fossil small mammal teeth using a combination of microcomputed tomography, object based image analysis and voxel modeling. Small mammal teeth, because of their durability, are widely found in Cenozioc sediments the world over and play a key role in stratigraphy as well as in researching the rapid evolution and the paleogeographic spreading of small mammals. Recent advances in microcomputed tomography make this non-destructive analysis method an ideal data source for high-resolution 3D models of fossil small animal teeth. To derive internally consistent solid models of such fossils from micro-CT imagery, we propose a combination of 3D object based image analysis and solid modeling. Incorporating paleontological expert knowledge in the image processing cycle, object based image analysis yields topologically consistent image stacks classified by the main tooth components—enamel, dentine and pulp. Forwarding these data to a voxel modeling system, they can be quantitatively analyzed in an unprecedented manner: going beyond the possibilities of the state-of-art surface models, solid models are capable of unambiguously portraying the entire object volume—teeth can be peeled by material properties, subvolumes can be extracted and automatically analyzed by Boolean operations. The proposed method, which can be flexibly extended to handle a range of paleontological and geological micro-objects, is demonstrated with two typical fossil small mammal teeth.

  8. Translucency measurements in teeth and dental materials

    NASA Astrophysics Data System (ADS)

    Rawicz, Andrew H.; Melnyk, Ivan; Kowalski, Pawel

    2003-06-01

    Exact color matching of dental restorative materials to vital teeth is a difficult task. There are several reasons for this difficulty and they will be elaborated upon in the presentation. One of the most important reasons is the fact that teeth, as well as dental restorative materials are translucent, and thus the color impression is a product of light scattering, back scattering, transmission, and spectral modifications inside of these objects. Classic colorimetry is insufficient to provide an exact color match. Additional information about the translucency factor of the considered object (material and geometry) is necessary to provide full reproducibility. Translucency has a direct effect on perceived brightness. In this article we describe the TransluDent, a complementary product to ColorDent, which measures translucency of teeth and dental materials. TransluDent determines translucency by measuring light transmitted through an object and light scattered inside of the object. The translucency measurements were performed on two groups of subjects. One group consisted of people in their twenties and the second group of subjects was in fifties. For comparison several sets of dental shade-guides were also tested. The great discrepancy in translucency factor between human teeth and popular on the market shades may explain difficulty in color matching of dental restorative materials to teeth.

  9. Wear and surface roughness of bovine enamel submitted to bleaching.

    PubMed

    Mondelli, Rafael Francisco Lia; Azevedo, Juliana Felippi David E Góes De; Francisconi, Paulo Afonso Silveira; Ishikiriama, Sérgio Kiyoshi; Mondelli, José

    2009-01-01

    The present study evaluated surface roughness and wear of bovine enamel following three different bleaching techniques and simulated brushing. Initial surface roughness (Ra) was evaluated and teeth were randomly divided into 4 groups (n = 10): Group 1, control; Group 2, 35% hydrogen peroxide (HP) activated by a hybrid light; Group 3, 35% HP activated by a halogen light; and Group 4, 16% carbamide peroxide. After bleaching, surface roughness was measured and teeth were subjected to 100,000 cycles of simulated brushing. After brushing, the final roughness and wear was determined. Data were statistically analyzed by ANOVA and Tukey test (P < 0.05). There were no significant differences among groups comparing initial and postbleaching roughness. After brushing, significant differences were found between the control and experimental groups. Group 4 showed a significant increase in roughness values compared with Group 2. The control group showed significantly less wear than other groups. Bleaching techniques promoted increased roughness and wear of bovine enamel, when submitted to simulated brushing. Tooth enamel after bleaching can present a larger alteration in the amount of roughness due to brushing.

  10. Extreme strength observed in limpet teeth

    PubMed Central

    Barber, Asa H.; Lu, Dun; Pugno, Nicola M.

    2015-01-01

    The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GPa and was independent of sample size. These observations highlight an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres. This considerable tensile strength of limpet teeth is attributed to a high mineral volume fraction of reinforcing goethite nanofibres with diameters below a defect-controlled critical size, suggesting that natural design in limpet teeth is optimized towards theoretical strength limits. PMID:25694539

  11. Nonlinear viscoelastic characterization of bovine trabecular bone.

    PubMed

    Manda, Krishnagoud; Wallace, Robert J; Xie, Shuqiao; Levrero-Florencio, Francesc; Pankaj, Pankaj

    2017-02-01

    The time-independent elastic properties of trabecular bone have been extensively investigated, and several stiffness-density relations have been proposed. Although it is recognized that trabecular bone exhibits time-dependent mechanical behaviour, a property of viscoelastic materials, the characterization of this behaviour has received limited attention. The objective of the present study was to investigate the time-dependent behaviour of bovine trabecular bone through a series of compressive creep-recovery experiments and to identify its nonlinear constitutive viscoelastic material parameters. Uniaxial compressive creep and recovery experiments at multiple loads were performed on cylindrical bovine trabecular bone samples ([Formula: see text]). Creep response was found to be significant and always comprised of recoverable and irrecoverable strains, even at low stress/strain levels. This response was also found to vary nonlinearly with applied stress. A systematic methodology was developed to separate recoverable (nonlinear viscoelastic) and irrecoverable (permanent) strains from the total experimental strain response. We found that Schapery's nonlinear viscoelastic constitutive model describes the viscoelastic response of the trabecular bone, and parameters associated with this model were estimated from the multiple load creep-recovery (MLCR) experiments. Nonlinear viscoelastic recovery compliance was found to have a decreasing and then increasing trend with increasing stress level, indicating possible stiffening and softening behaviour of trabecular bone due to creep. The obtained parameters from MLCR tests, expressed as second-order polynomial functions of stress, showed a similar trend for all the samples, and also demonstrate stiffening-softening behaviour with increasing stress.

  12. Variation in Cuspal Morphology in Maxillary First Permanent Molar with Report of 3 Cusp Molar- A Prevalence Study

    PubMed Central

    2016-01-01

    Introduction Human teeth has always been known for morphological variations in both the crown and root structures. The corono-morphological variations can be in the form of extra cusp or missing cusp. Permanent maxillary first molars are the biggest teeth in maxillary arch and have a high anchorage value and are known for their four cusp and five cusp patterns, if present with cusp of Carebelli. Aim The aim of this study was to determine the prevalence of cuspal variations and quantification of cusps of permanent maxillary first molar in Malwa population. Materials and Methods A total of 1249 individuals were studied at Government College of Dentistry, Indore, Madhya Pradesh, India, to evaluate the number of cusps in permanent maxillary first molars. Results Of the studied 1249 individuals, permanent maxillary first molars had five cusps in 407 (32.6%) cases while 838 (67.08%) cases had four cusp and four (0.32%) cases had three cusps. The four cases having three cusp permanent maxillary first molars were present unilaterally and only in females. Conclusion This article emphasizes the presence of permanent maxillary first molar with only three cusps in the Malwa population of India. It also reviews the literature in respect to this rare anomaly and calls for continuous and close monitoring to report such cases in the future. PMID:27790576

  13. ESR dating of teeth from Brazilian megafauna

    NASA Astrophysics Data System (ADS)

    Oliveira, L. C.; Kinoshita, A.; Barreto, A. M. F.; Figueiredo, A. M.; Silva, J. L. L.; Baffa, O.

    2010-11-01

    The study of radiation defects created in biomaterials, such as bone and teeth, can be used in dating with importance to palaeontology and archaeology. Two Stegomastodon teeth (AL1 and AL2) from north-eastern Brazilian megafauna were studied by electron spin resonance (ESR) spectroscopy. The samples were collected in Fazenda Ovo da Ema, (913349 / 3714965) UTM, Alagoas state, Brazil. The dating of these samples can contribute to the better knowledge of megafauna presence in this region as well as to the events associated to the extinction of these species.

  14. Frequency and distribution of early tooth loss and endodontic treatment needs of permanent first molars in a Turkish pediatric population

    PubMed Central

    Demirbuga, Sezer; Tuncay, Oznur; Cantekin, Kenan; Cayabatmaz, Muhammed; Dincer, Asiye Nur; Kilinc, Halil İbrahim; Sekerci, Ahmet Ercan

    2013-01-01

    Objectives: The objective of this study is to evaluate the frequency and distribution of early tooth loss and endodontic treatment needs of permanent first molars in a Turkish pediatric population. Materials and Methods: A total of 7,895 panoramic radiographs taken for routine dental examination at the Department of Oral Maxillofacial Radiology between 2008 and 2012 years were investigated. Two independent specialists evaluated early tooth loss and endodontic treatment needs of permanent first molars using panoramic radiography and patient anamnesis forms. The teeth were classified according to the following data: (a) Missing teeth, (b) teeth requiring extraction, (c) endodontically treated teeth (ETT), (d) teeth requiring endodontic therapy. The data also classified according to four factors: Age group (6-12 and 13-16), gender (boy and girl), jaw (mandible and maxilla) and side (right and left). A Chi-square test was used for statistical analyses. Results: A total of 19,488 and 12,092 teeth were evaluated in the child group and adolescent group respectively. All data were higher in adolescents than children (P < 0.001). For gender factor, only ETT was higher in girls than it was in boys (P < 0.001). For the jaw factor, all data were higher (P < 0.001) in mandible than in the maxilla. For the side factor, no statistical difference existed between right and left. Conclusions: Early tooth loss and endodontic treatment needs of permanent first molars showed variability according to age groups and jaws. When the results were compared according to the side and gender factors, no statistical difference was found (P > 0.05) except with the data of ETT in gender groups. PMID:24966738

  15. Morphology of the occlusal surfaces of premolar and molar teeth as an indicator of age in the horse.

    PubMed

    Carmalt, J L; Allen, A L

    2008-09-01

    The purpose of this study was to investigate the use of cheek tooth occlusal surface morphology as an indicator of age in the horse using a blinded cross-sectional design. Twenty horses of varying age, breed and sex were used. Horses of known age (foaling date) were euthanized for reasons other than dental disease. Following disarticulation of the head and sectioning of the mandibles, cheek teeth were cleaned using running water and photographs were taken of each arcade. Using a computer-based program, the total surface area of each premolar and molar, the outer enamel ridge perimeter distance, infundibular surface areas and perimeter distances were measured. Further anatomical data were calculated from these measurements and a statistical analysis of the relationship between horse age and cheek tooth occlusal morphology was performed. Results indicated that multiple anatomical regions within the occlusal surface of the equine cheek tooth can be used as an indicator of age. There are important differences between mandibular and maxillary teeth as well as between teeth in the same dental arcade. Horse size is also of significance. The mesial infundibular surface area as a percentage of the total surface area of tooth 111, and the mesiodistal length of 1/2/3/4 09 teeth, most closely approximates age within our mathematical model. Cheek tooth morphological data can be used to predict age in horses that possess all their permanent dentition. In cases in which the age of horses cannot be accurately determined from incisor examination, cheek teeth may be used.

  16. Lodestone: Nature's own permanent magnet

    NASA Technical Reports Server (NTRS)

    Wasilewski, P.

    1976-01-01

    Magnetic hysteresis and microstructural details are presented which explain why the class of magnetic iron ores defined as proto-lodestones, can behave as permanent magnets, i.e. lodestones. Certain of these proto-lodestones which are not permanent magnets can be made into permanent magnets by charging in a field greater than 1000 oersted. This fact, other experimental observations, and field evidence from antiquity and the middle ages, which seems to indicate that lodestones are found as localized patches within massive ore bodies, suggests that lightning might be responsible for the charging of lodestones. The large remanent magnetization, high values of coercive force, and good time stability for the remanent magnetization are all characteristics of proto-lodestone iron ores which behave magnetically as fine scale ( 10 micrometer) intergrowths when subjected to magnetic hysteresis analysis. The magnetic results are easily understood by analysis of the complex proto lodestone microstructural patterns observable at the micrometer scale and less.

  17. A Novel approach of Esthetic Management and preserving Vitality of Dilacerated Permanent Maxillary Lateral Incisor

    PubMed Central

    Ravi, GR

    2016-01-01

    ABSTRACT Dilaceration of the permanent tooth usually is a consequence of traumatic injuries to the primary teeth. Although it may appear anywhere in the long axis of the tooth, i.e., crown, cementoenamel junction, or root, most often the root is involved. However, crown dilaceration is a rare condition representing 3% of the total injuries. Maxillary incisors are more susceptible to such injury and affected tooth may either erupt buccally or lingually or remain impacted. Hitherto, the treatment options also differ as per the clinical scenario. This article proposes a novel technique of restoring esthetic function of the affected permanent maxillary lateral incisor with crown-root dilaceration while preserving the vitality of tooth. How to cite this article: Achary RC, Ravi GR. A Novel approach of Esthetic Management and preserving Vitality of Dilacerated Permanent Maxillary Lateral Incisor. Int J Clin Pediatr Dent 2016;9(2):152-155. PMID:27365939

  18. Heritable bovine fetal abnormalities.

    PubMed

    Whitlock, B K; Kaiser, L; Maxwell, H S

    2008-08-01

    The etiologies for congenital bovine fetal anomalies can be divided into heritable, toxic, nutritional, and infectious categories. Although uncommon in most herds, inherited congenital anomalies are probably present in all breeds of cattle and propagated as a result of specific trait selection that inadvertently results in propagation of the defect. In some herds, the occurrence of inherited anomalies has become frequent, and economically important. Anomalous traits can affect animals in a range of ways, some being lethal or requiring euthanasia on humane grounds, others altering structure, function, or performance of affected animals. Veterinary practitioners should be aware of the potential for inherited defects, and be prepared to investigate and report animals exhibiting abnormal characteristics. This review will discuss the morphologic characteristics, mode of inheritance, breeding lines affected, and the availability of genetic testing for selected heritable bovine fetal abnormalities.

  19. 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

  20. Selenium in bovine spermatozoa.

    PubMed

    Niemi, S M; Kuzan, F B; Senger, P L

    1981-05-01

    This study investigated the association of selenium with ejaculated bovine spermatozoa. Over 75% of the radioactive spermatozoa. Over 75% of the radioactive selenium-75 was released after 30 min of incubation in 2 X 10(-3) dithiothreitol. Of the selenium-75 released by dithiothreitol, 85% was associated with spermatozoal protein. Protein containing selenium-75 was found predominantly in a single band after polyacrylamide gel electrophoresis. Molecular weight was approximately 21,500 daltons.

  1. A double-sided linear primary permanent magnet vernier machine.

    PubMed

    Du, Yi; Zou, Chunhua; Liu, Xianxing

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed.

  2. A Double-Sided Linear Primary Permanent Magnet Vernier Machine

    PubMed Central

    2015-01-01

    The purpose of this paper is to present a new double-sided linear primary permanent magnet (PM) vernier (DSLPPMV) machine, which can offer high thrust force, low detent force, and improved power factor. Both PMs and windings of the proposed machine are on the short translator, while the long stator is designed as a double-sided simple iron core with salient teeth so that it is very robust to transmit high thrust force. The key of this new machine is the introduction of double stator and the elimination of translator yoke, so that the inductance and the volume of the machine can be reduced. Hence, the proposed machine offers improved power factor and thrust force density. The electromagnetic performances of the proposed machine are analyzed including flux, no-load EMF, thrust force density, and inductance. Based on using the finite element analysis, the characteristics and performances of the proposed machine are assessed. PMID:25874250

  3. Torque Characteristics of Saturated Permanent-Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Takahashi, Akeshi; Kikuchi, Satoshi; Wakui, Shinichi; Mikami, Hiroyuki; Ide, Kazumasa; Shima, Kazuo

    The evaluation of torque characteristics in a saturated magnetic field for permanent-magnet (PM) synchronous motors is presented. The torque saturation characteristics of non-salient and salient pole machines are investigated by finite element analysis and measurement. Thus, it is found that the torque saturation originates in the magnetic saturation in both the stator teeth, which are located on the leading position toward the direct axis, and in the stator back yoke, which is located on the lagging position toward the direct axis. This mechanism can also explain the reason for the significant torque saturation in the salient-pole machine; the higher inductance of the quadrature axis of the salient-pole machine causes a significant magnetic saturation in the stator back yoke. Therefore, less saliency or a wider back yoke can improve the torque saturation.

  4. Sterilisation of extracted human teeth for educational use.

    PubMed

    Kumar, M; Sequeira, P S; Peter, S; Bhat, G K

    2005-10-01

    Sixty intact, non-carious and unrestored teeth extracted due to periodontal disease were used to determine the most effective method of sterilisation. The teeth were divided into six groups, each containing 10 teeth. Group 1 teeth were immersed in 10% formalin for seven days, group 2 teeth were immersed in 3% hydrogen peroxide for seven days, group 3 teeth were immersed in 2.6% sodium hypochlorite for seven days, group 4 teeth were boiled in water at 100 degrees C for 20 minutes, group 5 teeth were autoclaved at 121 degrees C at 15 lbs psi for 30 minutes, and group 6 teeth were immersed in normal saline for seven days. After the treatment, the teeth were individually inoculated into trypticase soy broth and incubated for 48 hours. A questionnaire survey was also conducted to determine the awareness of dental students regarding infection due to extracted human teeth and the common disinfection/sterilisation methods used. Autoclaving at 121 degrees C, 15 lbs psi for 30 minutes and immersion in 10% formalin for seven days were effective in disinfecting/sterilising extracted human teeth. Chemicals such as 2.6% sodium hypochlorite, 3% hydrogen peroxide and boiling in water were not effective. The results indicate that autoclaving for 30 minutes or immersion in 10% formalin for seven days could be effectively used for disinfection/sterilisation of extracted human teeth.

  5. Dynamic characterization of teeth by laser vibrometry

    NASA Astrophysics Data System (ADS)

    Castellini, Paolo; Miglietta, G.; Revel, Gian M.; Scalise, Lorenzo

    1998-06-01

    The use of air compressed, high rotational velocity drill and of ultrasound devices in the dentist practice can cause pain for the patient and damage to the tooth structure. The authors in this paper have investigated the possible cause of these problems: the vibrations caused by the drill exciting the tooth. Particular attention has been dedicated to the frequency behavior of teeth, in order to individualize their frequency resonances. A method for the investigation of human teeth dynamic response, in terms of natural frequencies and modal shapes has been proposed. Very short laser pulses have been used to excite teeth vibrations and a scanning laser doppler vibrometer to measure the dynamic response. An assessment of the amplitude of the characteristics of the excitation has been done using the theory of the impulse response function in such a way as to calculate the frequency response of the teeth. The results measured have been compared. Results permit to extract information extremely useful for the design of devices used in the dentist practice.

  6. Hierarchical structure and biomineralization in cricket teeth

    NASA Astrophysics Data System (ADS)

    Xing, Xue-Qing; Gong, Yu; Cai, Quan; Mo, Guang; Du, Rong; Chen, Zhong-Jun; Wu, Zhong-Hua

    2013-02-01

    The cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of cricket teeth are always interesting. Synchrotron radiation X-ray fluorescence, X-ray diffraction, and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. A scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of a cricket tooth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. The interior of the tooth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points towards the top of the tooth cusp. The microfibrils aggregate randomly into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp is proposed and a detailed discussion is given in this paper.

  7. Treatment rationale of fractured posterior teeth.

    PubMed

    Silvestri, A R; Singh, I

    1978-11-01

    The four types of fractures most frequently encountered in posterior teeth--obliquely directed complete fractures, vertically directed complete fractures, obliquely directed incomplete fractures, and vertically directed incomplete fractures--have been described. A detailed treatment approach for each type has been presented.

  8. Elephant teeth from the atlantic continental shelf.

    PubMed

    Whitmore, F C; Emery, K O; Cooke, H B; Swift, D J

    1967-06-16

    Teeth of mastodons and mammoths have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, anz relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25,000 years.

  9. 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.

  10. Elephant teeth from the atlantic continental shelf

    USGS Publications Warehouse

    Whitmore, F.C.; Emery, K.O.; Cooke, H.B.S.; Swift, D.J.P.

    1967-01-01

    Teeth of mastodons and mastodons have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, and relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25.000 years.

  11. Simulation of a flow around biting teeth

    NASA Astrophysics Data System (ADS)

    Narusawa, Hideaki; Yamamoto, Eriko; Kuwahara, Kunio

    2008-11-01

    We simulated a flow around biting teeth. The decayed tooth is a disease that a majority of people are annoyed. These are often generated from a deep groove at occlusal surface. It is known that a person who bites well doesn't suffer from a decayed tooth easily. Biting forces reach as much as 60 kg/cm^2 by an adult male, and when chewing, upper and lower teeth approach to bite by those forces. The crushed food mixed with saliva becomes high viscosity fluid, and is pushed out of ditches of teeth in the direction of the cheek or the tongue. Teeth with complex three dimension curved surface are thought to form venturi at this time, and to generate big pressure partially. An excellent dental articulation will possibly help a natural generation of a flow to remove dental plaque, i.e. the cause of the decayed tooth. Moreover, the relation of this flow with the destruction of the filled metal or the polymer is doubted. In this research, we try to clarify the pressure distributions by this flow generation as well as its dynamics when chewing. One of our goals is to enable an objective design of the shape of the dental fillings and the artificial tooth. Tooth has a very small uneven ground and a bluff body. In this case, to calculate a computational numerical simulation to solve the Navier-Stokes equations three dimension Cartesian coordinate system is employed.

  12. Modification Of Gear Teeth To Reduce Vibrations

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Oswald, Fred B.; Lin, Hsiang Hsi

    1990-01-01

    Computer simulations yield data useful in designing for low noise. Effects of modifications in shape of gear teeth upon static transmission error and dynamic loading of gears now analyzed systematically. Design curves generated by conducting numerical simulations of dynamic effects at successive incremental modifications of gear systems operated at various applied loads. Modifications that result in minimum dynamic effect determined from design curves.

  13. Computing Contact Stresses In Gear Teeth

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Somprakit, Paisan; Huston, Ronald L.

    1995-01-01

    Improved method of computing contact stresses in gear teeth accounts for complicating effects like those of static and sliding friction. Provides iterative procedure for determination of contact region and nodal contact forces along with contact stresses. Method based on equations and computational procedure incorporating these effects routinely.

  14. Do We Need National Standards with Teeth?

    ERIC Educational Resources Information Center

    Usiskin, Zalman

    2007-01-01

    The author, director of the University of Chicago School Mathematics Project, tackles the following question: Should the United States have national standards with teeth, that is, a single set of standards tied to assessments and agreed to by the states? Proponents advance five main arguments for implementing such a standard. In his rebuttal, the…

  15. How to Care for Your Baby's Teeth

    MedlinePlus

    ... can use a wet washcloth or gauze to clean your baby’s teeth and gums. Start using a soft baby toothbrush and a small dab of toothpaste that does not have fluoride in it when your baby is between 1 ...

  16. Diagnostic imaging in bovine orthopedics.

    PubMed

    Kofler, Johann; Geissbühler, Urs; Steiner, Adrian

    2014-03-01

    Although a radiographic unit is not standard equipment for bovine practitioners in hospital or field situations, ultrasound machines with 7.5-MHz linear transducers have been used in bovine reproduction for many years, and are eminently suitable for evaluation of orthopedic disorders. The goal of this article is to encourage veterinarians to use radiology and ultrasonography for the evaluation of bovine orthopedic disorders. These diagnostic imaging techniques improve the likelihood of a definitive diagnosis in every bovine patient but especially in highly valuable cattle, whose owners demand increasingly more diagnostic and surgical interventions that require high-level specialized techniques.

  17. Magnetic Fields: Visible and Permanent.

    ERIC Educational Resources Information Center

    Winkeljohn, Dorothy R.; Earl, Robert D.

    1983-01-01

    Children will be able to see the concept of a magnetic field translated into a visible reality using the simple method outlined. Standard shelf paper, magnets, iron filings, and paint in a spray can are used to prepare a permanent and well-detailed picture of the magnetic field. (Author/JN)

  18. [Calcium hydroxide in the treatment of traumatized teeth].

    PubMed

    Cvek, M

    1989-09-01

    Calcium hydroxide is used in the treatment of different traumatized teeth. New concepts about the effects of calcium hydroxide on vital pulps and immature non vital teeth are developed. Some clinical techniques and their results are described.

  19. The large superpredators' teeth from Middle Triassic of Poland

    NASA Astrophysics Data System (ADS)

    Surmik, Dawid; Brachaniec, Tomasz

    2013-09-01

    An unusual large teeth, finding from time to time in marine sediments of Muschelkalk, Silesia, Poland indicate the superpredators occurrence. According to size and morphological features the teeth are similar to archosaurs or giant marine reptiles.

  20. Natal teeth: Case report and review of literature

    PubMed Central

    Rao, Roopa S; Mathad, Sudha V

    2009-01-01

    The presence of teeth at birth or within a month post-delivery is a rare condition. A newborn, a 2 days old female, with two mandibular incisor natal teeth was examined. The teeth were mobile and were extracted because of the fear of aspiration and refusal to feed. The purpose of this report is to review the literature related to natal teeth epidemiology and discuss their possible etiology and treatment. PMID:21886998

  1. Something to sink your teeth into: The presence of teeth augments ERPs to mouth expressions.

    PubMed

    daSilva, Elizabeth B; Crager, Kirsten; Geisler, Danika; Newbern, Powell; Orem, Benjamin; Puce, Aina

    2016-02-15

    If the whites of the sclera can impact neural processing of eye expressions (Hardee, Thompson, & Puce, 2008; Whalen et al., 1998), do seen teeth affect neural responses to mouth expressions? Twenty participants (10 females; ages 22-31) viewed avatar mouth images depicting grimaces, smiles and open mouth expressions that were presented with and without teeth. A continuous 256 channel electroencephalogram (EEG) was recorded while subjects completed two tasks: an implicit task evaluating stimulus color and an explicit task evaluating mouth expression valence. Event related potential (ERP) peak amplitudes and latencies and area under the curve (AUC) were measured in individual subject averaged ERPs. Statistical testing revealed a main effect of the presence of Teeth for P100, N170, and vertex positive potential (VPP) amplitudes and for slow positive wave (SPW) AUC. Task by teeth interactions occurred for P250 amplitude, underscoring how explicit task demands can influence neural processing. Arousal ratings co-varied with teeth presence, suggesting that low-level visual features such as teeth may drive the saliency of emotional expressions, and lie at the core of differences in neural processing to different emotional expressions.

  2. Bovine Intestinal Alkaline Phosphatase Reduces Inflammation After Induction of Acute Myocardial Infarction in Mice

    PubMed Central

    Fiechter, Danielle; Kats, Suzanne; Brands, Ruud; van Middelaar, Ben; Pasterkamp, Gerard; de Kleijn, Dominique; Seinen, Willem

    2011-01-01

    Background There has been increasing evidence suggesting that lipopolysaccharide or endotoxin may be an important activator of the innate immune system after acute myocardial infarction. Bovine intestinal alkaline phosphatase reduces inflammation in several endotoxin mediated diseases by dephosphorylation of the lipid A moiety of lipopolysaccharide. The aim of this study was to investigate the effect of bovine intestinal alkaline phosphatase on reducing inflammation after acute myocardial infarction. Methods Just before permanent ligation of the left anterior descending coronary (LAD) artery to induce acute myocardial infarction in Balb/c mice, bovine intestinal alkaline phosphatase (bIAP) was administrated intravenously. After 4 hours, mice were sacrificed and the inflammatory response was assessed. Acute myocardial infarction induced the production of different cytokines, which were measured in blood. Results Treatment with bovine intestinal alkaline phosphatase resulted in a significant reduction of the pro-inflammatory cytokines IL-6, IL-1β and the chymase mouse mast cell protease-1. No difference in the production of the anti-inflammatory cytokine IL-10 was observed between the control group and the bovine intestinal alkaline phosphatase treated group. Conclusion In a mouse model of permanent LAD coronary artery ligation, bIAP diminishes the pro-inflammatory responses but does not have an effect on the anti-inflammatory response in the acute phase after acute myocardial infarction.

  3. Analyses of the Erosive Effect of Dietary Substances and Medications on Deciduous Teeth.

    PubMed

    Lussi, Adrian; Carvalho, Thiago Saads

    2015-01-01

    This study aimed at analysing the erosive potential of 30 substances (drinks, candies, and medicaments) on deciduous enamel, and analyse the associated chemical factors with enamel dissolution. We analysed the initial pH, titratable acidity (TA) to pH 5.5, calcium (Ca), inorganic phosphate (Pi), and fluoride (F) concentration, and degree of saturation ((pK -pI)HAP, (pK -pI)FAP, and (pK-pI)CaF2) of all substances. Then, we randomly distributed 300 specimens of human deciduous enamel into 30 groups (n = 10 for each of the substances tested. We also prepared 20 specimens of permanent enamel for the sake of comparison between the two types of teeth, and we tested them in mineral water and Coca-Cola®. In all specimens, we measured surface hardness (VHN: Vickers hardness numbers) and surface reflection intensity (SRI) at baseline (SH baseline and SRI baseline), after a total of 2 min (SH2 min) and after 4 min (SH4 min and SRI4 min) erosive challenges (60 ml of substance for 6 enamel samples; 30°C, under constant agitation at 95 rpm). There was no significant difference in SH baseline between deciduous and permanent enamel. Comparing both teeth, we observed that after the first erosive challenge with Coca-Cola®, a significantly greater hardness loss was seen in deciduous (-90.2 ± 11.3 VHN) than in permanent enamel (-44.3 ± 12.2 VHN; p = 0.007), but no differences between the two types of teeth were observed after two challenges (SH4 min). After both erosive challenges, all substances except for mineral water caused a significant loss in relative surface reflectivity intensity, and most substances caused a significant loss in surface hardness. Multiple regression analyses showed that pH, TA and Ca concentration play a significant role in initial erosion of deciduous enamel. We conclude that drinks, foodstuffs and medications commonly consumed by children can cause erosion of deciduous teeth and erosion is mainly associated with pH, titratable acidity and calcium

  4. Analyses of the Erosive Effect of Dietary Substances and Medications on Deciduous Teeth

    PubMed Central

    Lussi, Adrian; Carvalho, Thiago Saads

    2015-01-01

    This study aimed at analysing the erosive potential of 30 substances (drinks, candies, and medicaments) on deciduous enamel, and analyse the associated chemical factors with enamel dissolution. We analysed the initial pH, titratable acidity (TA) to pH 5.5, calcium (Ca), inorganic phosphate (Pi), and fluoride (F) concentration, and degree of saturation ((pK -pI)HAP, (pK -pI)FAP, and (pK−pI)CaF2) of all substances. Then, we randomly distributed 300 specimens of human deciduous enamel into 30 groups (n = 10 for each of the substances tested. We also prepared 20 specimens of permanent enamel for the sake of comparison between the two types of teeth, and we tested them in mineral water and Coca-Cola®. In all specimens, we measured surface hardness (VHN: Vickers hardness numbers) and surface reflection intensity (SRI) at baseline (SHbaseline and SRIbaseline), after a total of 2 min (SH2min) and after 4 min (SH4min and SRI4min) erosive challenges (60 ml of substance for 6 enamel samples; 30°C, under constant agitation at 95 rpm). There was no significant difference in SHbaseline between deciduous and permanent enamel. Comparing both teeth, we observed that after the first erosive challenge with Coca-Cola®, a significantly greater hardness loss was seen in deciduous (−90.2±11.3 VHN) than in permanent enamel (−44.3±12.2 VHN; p = 0.007), but no differences between the two types of teeth were observed after two challenges (SH4min). After both erosive challenges, all substances except for mineral water caused a significant loss in relative surface reflectivity intensity, and most substances caused a significant loss in surface hardness. Multiple regression analyses showed that pH, TA and Ca concentration play a significant role in initial erosion of deciduous enamel. We conclude that drinks, foodstuffs and medications commonly consumed by children can cause erosion of deciduous teeth and erosion is mainly associated with pH, titratable acidity and calcium

  5. 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...

  6. 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...

  7. [Extraction of 56 horizontally impacted teeth using dental implanter].

    PubMed

    Zhang, Yan-ping; Liang, Na

    2005-06-01

    50 cases, totally 56 horizontally impacted teeth were extracted using dental implanter to remove the alveolar bone. Another 56 horizontally impacted teeth were extracted using high speed turbine.It's concluded that is a safe and easy way using the dental implanter to remove the horizontally impacted teeth, and the reaction and the complications could be minimized.

  8. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (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 Food and Drugs 8 2014-04-01 2014-04-01 false Heat source for bleaching teeth. 872.6475...

  9. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (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 Food and Drugs 8 2012-04-01 2012-04-01 false Heat source for bleaching teeth. 872.6475...

  10. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (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 Food and Drugs 8 2013-04-01 2013-04-01 false Heat source for bleaching teeth. 872.6475...

  11. Palatal displacement of canine is genetic and related to congenital absence of teeth.

    PubMed

    Pirinen, S; Arte, S; Apajalahti, S

    1996-10-01

    The palatally displaced canine is a harmful complication of dental development. It appears in 1 to 2% of the Western population. According to our clinical experience, this anomaly is seen in families in which missing and peg-shaped teeth are common. It could be caused by the same genetic component that causes incisor-premolar hypodontia. We examined 106 patients who had been operated on and treated orthodontically for palatally impacted canine(s). The patients and their family members were examined for dental anomalies. One hundred and ten first- and 93 second-degree relatives were clinically and radiologically examined, and 35 pedigrees were constructed. Thirty-six percent of the patients had congenitally missing permanent teeth (hypodontia), which is 4.5 times the population prevalence. Hypodontia was noted in 19 to 20% of both the first- and second-degree relatives. This is 2.5 times the population prevalence. Frequency of missing teeth, analyzed by tooth groups, was of the same order as that shown for incisor-premolar hypodontia in the Western population. In six of the 35 pedigrees, a palatally impacted canine was noted in several generations of the same family. Prevalence of this anomaly was 4.9% in the studied group, which is 2.5 times the population prevalence. From the findings, we conclude that the palatally displaced canine belongs to the spectrum of dental abnormalities related to hypodontia.

  12. Longitudinal Evaluation of the Structural Integrity of Teeth Affected by Molar Incisor Hypomineralisation.

    PubMed

    Bullio Fragelli, Camila Maria; Jeremias, Fabiano; Feltrin de Souza, Juliana; Paschoal, Marco Aurélio; de Cássia Loiola Cordeiro, Rita; Santos-Pinto, Lourdes

    2015-01-01

    The aim of this prospective cohort study was to evaluate the risk of posteruptive breakdown and the development of caries lesions in teeth with molar incisor hypomineralisation (MIH). A total of 367 permanent incisors and first molars, affected and not affected by MIH lesions, of 45 children with MIH from Araraquara, São Paulo, Brazil, were evaluated at intervals from 6 to 12 months by assessing the severity of MIH, the presence of tooth caries lesions and the treatment needed. During the study period, all patients received preventive care. The data were analysed using Fisher's exact test and actuarial method survival analysis. Significant associations were also found in teeth between the presence of MIH and a DMFT index >0 in all periods and also between the need for treatment and the presence of MIH. The teeth affected by MIH opacities were healthy in 99% of incisors and 93% of molars at the end of the 12-month period. Due to the high likelihood of maintaining the tooth structure in opacities, the complete or premature removal of the affected area is not justified.

  13. Cleidocranial dysplasia case report: remodeling of teeth as aesthetic restorative treatment.

    PubMed

    da Cunha, Leonardo Fernandes; Caetano, Isabela Maria; Dalitz, Fernando; Gonzaga, Carla Castiglia; Mondelli, José

    2014-01-01

    Cleidocranial dysplasia (CCD), is an autosomal dominant disorder with a prevalence of 1 in 1,000,000 individuals. It is generally characterized by orofacial manifestations, including enamel hypoplasia, retained primary teeth, and impacted permanent and supernumerary teeth. The successful treatment involving a timing intervention (orthodontic-maxillofacial surgeons-restorative) is already described. However, the restorative treatment might improve the aesthetic final result in dentistry management for patients with cleidocranial dysplasia. Objective. Therefore, this clinical report presents a conservative restorative management (enamel microabrasion, dental bleaching, and direct composite resin) for aesthetic solution for a patient with CCD. Clinical Considerations. The cosmetic remodeling is a conservative, secure, and low cost therapy that can be associated with other procedures such as enamel microabrasion and dental bleaching to achieve optimal outcome. Additionally, the Golden Proportion can be used to guide dental remodeling to improve the harmony of the smile and the facial composition. Conclusions. Thus, dentists must know and be able to treat dental aesthetic problems in cleidocranial dysplasia patients. The intention of this paper is to describe a restorative approach with the cosmetic remodeling teeth (by grinding or addicting material) associated with enamel microabrasion and dental bleaching to reestablish the form, shape, and color of smile for patients with cleidocranial dysplasia.

  14. Cone-beam computed tomography as a surgical guide to impacted anterior teeth

    PubMed Central

    Jeremias, Fabiano; Fragelli, Camila Maria Bullio; Mastrantonio, Simone Di Salvo; dos Santos-Pinto, Lourdes; dos Santos-Pinto, Ary; Pansani, Cyneu Aguiar

    2016-01-01

    Surgical procedure for removal of impacted teeth is a challenge for clinicians as it involves accuracy in the diagnosis and localization of the dental elements. The cone-beam computed tomography (CBCT), compared to the conventional radiography, has a greater potential to provide complementary information because of its three-dimensional (3D) images, reducing the possibility of failures in surgical procedures. Two 10-year-old boys presented with aesthetic issues associated with the juxtaposition of ectopic teeth with the permanent ones. Both two-dimensional and 3D preoperative radiographic diagnostic sets were produced. The occlusal and panoramic radiographs were not enough for proper localization of impacted incisors. Thus, the CBCT was used as a surgical guide. After 2 years of longitudinal following, no lesion was recorded, and the orthodontic treatment has proven successful. In all cases, CBCT contributed to both diagnosis and correct localization of supernumerary teeth, aiding the professional in the treatment planning, and consequently in the clinical success. The surgeries were completely safe, avoiding damage in noble structures, and providing a better recovering of the patients. PMID:26962322

  15. Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.; Scharrer, Joseph K.

    1987-01-01

    An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

  16. Modified cuspal relationships of mandibular molar teeth in children with Down's syndrome

    PubMed Central

    PERETZ, BENJAMIN; SHAPIRA, JOSEPH; FARBSTEIN, HANNA; ARIELI, ELIAHU; SMITH, PATRICIA

    1998-01-01

    A total of 50 permanent mandibular 1st molars of 26 children with Down's syndrome (DS) were examined from dental casts and 59 permanent mandibular 1st molars of normal children were examined from 33 individuals. The following measurements were performed on both right and left molars (teeth 46 and 36 respectively): (a) the intercusp distances (mb-db, mb-d, mb-dl, db-ml, db-d, db-dl, db-ml, d-dl, d-ml, dl-ml); (b) the db-mb-ml, mb-db-ml, mb-ml-db, d-mb-dl, mb-d-dl, mb-dl-d angles; (c) the area of the pentagon formed by connecting the cusp tips. All intercusp distances were significantly smaller in the DS group. Stepwise logistic regression, applied to all the intercusp distances, was used to design a multivariate probability model for DS and normals. A model based on 2 distances only, mb-dl and mb-db, proved sufficient to discriminate between the teeth of DS and the normal population. The model for tooth 36 for example was as follows: formula here A similar model for tooth 46 was also created, as well as a model which incorporated both teeth. With respect to the angles, significant differences between DS and normals were found in 3 out of the 6 angles which were measured: the d-mb-dl angle was smaller than in normals, the mb-d-dl angle was higher, and the mb-dl-d angle was smaller. The dl cusp was located closer to the centre of the tooth. The change in size occurs at an early stage, while the change in shape occurs in a later stage of tooth formation in the DS population. PMID:10029186

  17. Bovine leukocyte adhesion deficiency (BLAD): a review.

    PubMed

    Nagahata, Hajime

    2004-12-01

    Bovine leukocyte adhesion deficiency (BLAD) in Holstein cattle is an autosomal recessive congenital disease characterized by recurrent bacterial infections, delayed wound healing and stunted growth, and is also associated with persistent marked neutrophilia. The molecular basis of BLAD is a single point mutation (adenine to guanine) at position 383 of the CD18 gene, which caused an aspartic acid to glycine substitution at amino acid 128 (D128G) in the adhesion molecule CD18. Neutrophils from BLAD cattle have impaired expression of the beta2 integrin (CD11a,b,c/CD18) of the leukocyte adhesion molecule. Abnormalities in a wide spectrum of adherence dependent functions of leukocytes have been fully characterized. Cattle affected with BLAD have severe ulcers on oral mucous membranes, severe periodontitis, loss of teeth, chronic pneumonia and recurrent or chronic diarrhea. Affected cattle die at an early age due to the infectious complications. Holstein bulls, including carrier sires that had a mutant BLAD gene in heterozygote were controlled from dairy cattle for a decade. The control of BLAD in Holstein cattle by publishing the genotypes and avoiding the mating between BLAD carriers was found to be successful. This paper provides an overview of the genetic disease BLAD with reference to the disease in Holstein cattle.

  18. Replantation of permanent incisors in children using Emdogain.

    PubMed

    Barrett, Edward J; Kenny, David J; Tenenbaum, Howard C; Sigal, Michael J; Johnston, Douglas H

    2005-10-01

    The aim of this study was to determine whether application of an enamel matrix protein derivative, Emdogain (Biora AB Malmo, Sweden) to the root surface of avulsed permanent incisors would improve postreplantation outcomes in a pediatric population. Between June 1999 and May 2002, 25 avulsed permanent maxillary incisors (22 centrals and three laterals) were treated with Emdogain and followed for up to 32 months, mean duration 20.6 months (range: 6.9-32.5 months). Mean patient age at the time of treatment was 12.0 years (range: 7.7-17.6 years) and mean extra-alveolar duration was 185 min (range: 100-300 min). At the end of their follow-up each of the replanted incisors demonstrated radiographic evidence of replacement root resorption and clinical evidence of ankylosis. None of the replanted teeth were affected by inflammatory root resorption and there was no evidence of infection. When compared with the control samples from Barrett and Kenny (Endod Dent Traumatol 1997;15:269-72.) and Andersson et al. (Endod Dent Traumatol 1989;5:38-47.) this sample treated with the Emdogain protocol demonstrated significantly less root resorption than either of the control samples (anova, P < 0.0001). Although the Emdogain protocol did not produce periodontal regeneration, it did eliminate inflammatory resorption and infection and led to significantly less root resorption compared with the two historical controls.

  19. Is Malnutrition Associated with Crowding in Permanent Dentition?

    PubMed Central

    Thomaz, Erika B. A. F.; Cangussu, Maria Cristina T.; da Silva, Antônio Augusto M.; Assis, Ana Marlúcia O.

    2010-01-01

    Evidence suggests that energy-protein malnutrition is associated with impaired growth and development of facial bones. The objective of this study was to investigate the association between nutritional status and reduced space for dental eruption (crowding) in permanent dentition. A cross-sectional study with probabilistic sampling design was used. We evaluated 2,060 students aged 12 to 15 years enrolled in schools in the northeast of Brazil. Crowding was defined according to World Health Organization (WHO) as misalignment of teeth due to lack of space for them to erupt in the correct position. Nutritional status was evaluated by means of body mass index and height-for-age, using the WHO’s reference curves. Parents and adolescents responded to a questionnaire about demographic, socioeconomic, biological and behavioral characteristics. The associations were estimated by odds ratio (OR) in multivariate logistic regression analysis (alpha = 0.05). Confounding and effect-modification were taken into account. An association between low height-for-age (z-score < −1SD) and crowding was only observed in adolescents with a prolonged history of mouth breathing (OR = 3.1). No association was observed between underweight and crowding. Malnutrition is related to crowding in permanent dentition among mouth-breathing adolescents. Policy actions aimed at reducing low height-for-age and unhealthy oral habits are strongly recommended. However, further studies are needed to increase the consistency of these findings and improve understanding of the subject. PMID:20948941

  20. Linear Odontometric Analysis of Permanent Dentition as A Forensic Aid: A Retrospective Study

    PubMed Central

    Nair, Sunil Sukumaran; Gopakumar, Devi; Kurian, Nisha; Parameswar, Arjun; Baby, Tibin Kaithappillil

    2016-01-01

    Introduction Sex determination in forensic anthropology is an essential step for medico-legal purposes and crucial for identification as the number of possible matches is reduced to 50%. Teeth are an excellent material for anthropological, genetic, odontological and forensic investigations as they are known to resist a variety of ante-mortem and post-mortem insults. Sexual dimorphism in tooth size and the accuracy of odontometric sex prediction is found to vary in different population and therefore it is necessary to determine specific population values in order to make identification possible. Hence, the present study was undertaken to evaluate the existence of sexual dimorphism in South Kerala population. Aim To evaluate and estimate the degree of odontometric sexual dimorphism in all permanent teeth except third molars and the variations in odontometric dimensions between the left and right side teeth of the maxillary and mandibular arches in male and female groups. Materials and Methods The MesioDistal (MD) and BuccoLingual (BL) measurements of 28 teeth were estimated from the preorthodontic casts of 132 subjects; male group (66 males) and female group (66 females) of age range 15-25 years using digital Verniers’ Caliper. The data obtained were analysed using SPSS version 17 and the Students’ t-test for two independent samples. Results The MesioDistal (MD) and BuccoLingual (BL) parameters of all permanent teeth in the study group showed sexual dimorphism. Over 39% of the tooth variables showed reverse dimorphism. The comparison of mean values of MD and BL diameters of the maxillary and mandibular, right and left side teeth in male and female groups showed statistical significance in males whereas females show non-significant values in both MD and BL diameters. Conclusion The study showed a varied percentage of sexual dimorphism and variation in the mean values of MD and BL dimensions in males, but not in females between right and left side teeth of the

  1. Some Considerations on Simple Non-Linear Magnetic Analysis-Based Optimum Design of Multi-Pole Permanent Magnet Machines

    NASA Astrophysics Data System (ADS)

    Kano, Yoshiaki; Kosaka, Takashi; Matsui, Nobuyuki

    This paper presents a simple non-linear magnetic analysis-based optimum design of a multi-pole permanent magnet machine as an assistant design tool of 3D-FEM. The proposed analysis is based on the equivalent magnetic circuit and the air gap permeance model between the stator and rotor teeth of the motor, taking into account the local magnetic saturation in the pointed end of teeth. The availability of the proposed analysis is verified by comparing with 3D-FEM analysis from the standpoints of the torque calculation accuracy for the variations of design free parameter and the computation time. After verification, the proposed analysis-based optimum design of the dimensions of permanent magnet is examined, by which the minimization of magnet volume is realized while keeping torque/current ratio at the specified value.

  2. Tattoos and Permanent Make-Up

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Tattoos and Permanent Make-up Share Tweet Linkedin Pin ... Risks FDA's Role Tattoo Removal Options Types of Tattoos Permanent Tattoo : A needle inserts colored ink into ...

  3. Genetics Home Reference: permanent neonatal diabetes mellitus

    MedlinePlus

    ... Facebook Share on Twitter Your Guide to Understanding Genetic Conditions Search MENU Toggle navigation Home Page Search ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions permanent neonatal diabetes mellitus permanent ...

  4. An unusual case of black teeth.

    PubMed

    Schuurs, A H; Abraham-Inpijn, L; van Straalen, J P; Sastrowijoto, S H

    1987-10-01

    Loss of enamel and a deep black stain of the teeth in a 40-year-old diabetic patient are strongly suggested to be caused by the daily consumption of a cheap white wine and, possibly, by the chewing of cayenne. The wine proved to be rather acid, thereby promoting abrasion as a result of gnashing, and to contain a high concentration of tannin. The exact role of the tannins is described.

  5. Bleaching non vital primary teeth: case report.

    PubMed

    Bussadori, Sandra Kalil; Roth, Faynna; Guedes, Carolina Cardoso; Fernandes, Kristiane Porta; Domingues, Manoela Martins; Wanderley, Márcia Turolla

    2006-01-01

    Trauma and pulpal infections in primary dentition are part of the routine of the pediatric dentist. Common consequences in these cases are alterations in dental color, compromising patient's esthetics and his interaction in social environment. Bleaching intends to preserve dental structure already weakened and to show immediate esthetic results. This clinical case shows a bleaching technique in devitalized primary teeth using bleaching agent with 35% hydrogen peroxide activated by photo polymerizer. This technique is simple and shows immediate satisfactory results.

  6. ["Carious" and "noncarious" lesions of the hard dental tissues. Ultrastructural (SEM) and microanalytical (EDS) analyses of teeth from the 3rd century B.C].

    PubMed

    Caltabiano, C; Leonardi, R; Martinez, G; Viscuso, O; Romeo, M; Caltabiano, R

    1996-05-01

    The study was carried out on 80 teeth (70 of permanent dentition and 10 of primary one) of mandibular and maxillary bones. The teeth owned to subjects lived in the III c.b.C. in Sicily, and they were found in Naxos necropolis. The teeth were examined as far as carious and non carious lesions, then they were prepared for instrumental analyses by Scanning Electron Microscopy (SEM) and Energy dispersed X ray spectrometry (EDS). To an objective examination of the sample no caries were detected in the teeth sample apart one tooth, on the other hand there was an extensive occlusal abrasion, from a macroscopic point of view there were no difference as far teeth morphology. SEM examination pointed out all around dentinal tubules a circle of sclerotic dentin as reaction to occlusal wear. The amelocemental junction showed from a ultramicroscopic point of view an overlap of cementum onto enamel. EDS analysis pointed out a higher P concentration on the crown versus the root in all the teeth of the sample.

  7. Natal and Neonatal Teeth: An Overview of the Literature

    PubMed Central

    Mhaske, Shubhangi; Yuwanati, Monal B.; Mhaske, Ashok; Ragavendra, Raju; Kamath, Kavitha; Saawarn, Swati

    2013-01-01

    The occurrence of natal and neonatal teeth is an uncommon anomaly, which for centuries has been associated with diverse superstitions among different ethnic groups. Natal teeth are more frequent than neonatal teeth, with the ratio being approximately 3 : 1. It must be considered that natal and neonatal teeth are conditions of fundamental importance not only for a dental surgeon but also for a paediatrician since their presence may lead to numerous complications. Early detection and treatment of these teeth are recommended because they may induce deformity or mutilation of tongue, dehydration, inadequate nutrients intake by the infant, and growth retardation, the pattern and time of eruption of teeth and its morphology. This paper presents a concise review of the literature about neonatal teeth. PMID:24024038

  8. Eruption of third permanent molars after the extraction of second permanent molars. Part 2: Functional occlusion and periodontal status.

    PubMed

    Orton-Gibbs, S; Orton, S; Orton, H

    2001-03-01

    Functional occlusion and periodontal health were investigated after orthodontic treatment that involved extraction of second molars and after eruption of the third molars in 37 patients (25 female, 12 male). The mean age was 21 years 9 months (range, 16 years 1 month-30 years 5 months). The third permanent molars invariably erupted into a position that maintained good functional occlusion. Sixty-three percent of patients had canine guidance in lateral excursion; the remainder of patients had satisfactory group function. There were only 2 non-working side interferences in the sample, 1 from a recently erupted mandibular third molar. The periodontal health of the sample was generally excellent. Plaque score and bleeding on probing was very low (1.7% of sites). Periodontal health around both maxillary and mandibular teeth was extremely good. When attachment loss was assessed, 2238 of 2240 sites were clinically healthy. One patient, who had generally poor oral hygiene, had a 4-mm probing depth interproximally on the maxillary first and third molar contact. There was no correlation between periodontal health and mandibular third molar position. Therefore, both functional occlusion and periodontal health in the sample were good after loss of second permanent molars and eruption of the third molars.

  9. [The closed eruption technique in cases of impaction of permanent maxillary canines].

    PubMed

    van Schijndel, J E; de Lange, J; Baas, E M; Broers, P C

    2010-11-01

    The impaction of permanent maxillary canines occurs frequently. In recent decades, research has led to 2 methods of treatment: the modified window technique and the closed eruption technique. Although these methods have been described in detail, it is still not clear which method is most effective. In a study involving 73 orthodontic patients with an impacted, palatally displaced permanent maxillary canine, this cuspid was exposed by means of a gingival flap and an orthodontic bracket was immediately fixed on the exposed canine, after which the gingival flap was repositioned using sutures. The patients were clinically and radiographically examined 3 months after the orthodontic treatment. In a control group consisting of 93 orthodontic patients, there were no cases of impacted permanent maxillary cuspids. The overall success rate for the treatment in the study group was 63%. Problems in adjacent teeth were correlated significantly with older age among the patients. There was a significant difference in the number of pockets around the teeth adjacent to the canines in the study group and in the control group.

  10. Teaching Object Permanence: An Action Research Study

    ERIC Educational Resources Information Center

    Bruce, Susan M.; Vargas, Claudia

    2013-01-01

    "Object permanence," also known as "object concept" in the field of visual impairment, is one of the most important early developmental milestones. The achievement of object permanence is associated with the onset of representational thought and language. Object permanence is important to orientation, including the recognition of landmarks.…

  11. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  12. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  13. 21 CFR 886.4445 - Permanent magnet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove...

  14. Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth

    PubMed Central

    Kianimanesh, Nasrin; Shayeghi, Bahareh

    2014-01-01

    Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application. PMID:25110641

  15. Microleakage of CEM Cement and ProRoot MTA as Furcal Perforation Repair Materials in Primary Teeth

    PubMed Central

    Haghgoo, Roza; Arfa, Sara; Asgary, Saeed

    2013-01-01

    Introduction: Iatrogenic furcal perforation is a procedural accident in endodontic treatments of primary/permanent teeth; prognosis may be favorable if a complete seal with biomaterial is immediately established. The purpose of this in vitro study was to evaluate microleakage of calcium enriched mixture (CEM) cement and ProRoot mineral trioxide aggregate (MTA) for sealing primary molar furcal perforations. Materials and Methods This study was conducted on 38 extracted human primary molars. Furcation perforations were created in the pulp chamber floor. The teeth were divided randomly in two experimental groups (n=17) and two positive and negative controls (n=2). Perforations were then repaired with biomaterials. After 72 h, the teeth were submerged in 2% fuchsin dye solution for 24h. The samples were sectioned longitudinally and evaluated for dye leakage. Data analyzed statistically using ANOVA test. Results: The negative and positive controls behaved as expected. Dye microleakage was observed in all experimental samples; however, there was no statistically significant difference between the microleakage of MTA (4.411±2.042 mm) and CEM (3.647±1.040 mm) groups (P>0.05). Conclusion: Based on the findings of this in vitro study, CEM and tooth-colored ProRoot MTA have similar sealing ability for furcal perforation repair of primary molar teeth. PMID:24171027

  16. Permanent-File-Validation Utility Computer Program

    NASA Technical Reports Server (NTRS)

    Derry, Stephen D.

    1988-01-01

    Errors in files detected and corrected during operation. Permanent File Validation (PFVAL) utility computer program provides CDC CYBER NOS sites with mechanism to verify integrity of permanent file base. Locates and identifies permanent file errors in Mass Storage Table (MST) and Track Reservation Table (TRT), in permanent file catalog entries (PFC's) in permit sectors, and in disk sector linkage. All detected errors written to listing file and system and job day files. Program operates by reading system tables , catalog track, permit sectors, and disk linkage bytes to vaidate expected and actual file linkages. Used extensively to identify and locate errors in permanent files and enable online correction, reducing computer-system downtime.

  17. Plate-like permanent dental laminae of upper jaw dentition in adult gobiid fish, Sicyopterus japonicus.

    PubMed

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

    2010-04-01

    Sicyopterus japonicus (Teleostei, Gobiidae) possesses a unique upper jaw dentition different from that known for any other teleosts. In the adults, many (up to 30) replacement teeth, from initiation to attachment, are arranged orderly in a semicircular-like strand within a capsule of connective tissue on the labial side of each premaxillary bone. We have applied histological, ultrastructural, and three-dimensional imaging from serial sections to obtain insights into the distribution and morphological features of the dental lamina in the upper jaw dentition of adult S. japonicus. The adult fish has numerous permanent dental laminae, each of which is an infolding of the oral epithelium at the labial side of the functional tooth and forms a thin plate-like structure with a wavy contour. All replacement teeth of a semicircular-like strand are connected to the plate-like dental lamina by the outer dental epithelium and form a tooth family; neighboring tooth families are completely separated from each other. The new tooth germ directly buds off from the ventro-labial margin of the dental lamina, whereas no distinct free end of the dental lamina is present, even adjacent to this region. Cell proliferation concentrated at the ventro-labial margin of the dental lamina suggests that this region is the site for repeated tooth initiation. During tooth development, the replacement tooth migrates along a semicircular-like strand and eventually erupts through the dental lamina into the oral epithelium at the labial side of the functional tooth. This unique thin plate-like permanent dental lamina and the semicircular-like strand of replacement teeth in the upper jaw dentition of adult S. japonicus probably evolved as a dental adaptation related to the rapid replacement of teeth dictated by the specialized feeding habit of this algae-scraping fish.

  18. Root resorption of primary molars without successor teeth. An experimental study in the beagle dog.

    PubMed

    Lin, Bi-Chen; Zhao, Yu-Ming; Yang, Jie; Ge, Li-Hong

    2012-04-01

    Tooth agenesis is a common craniofacial congenital malformation in humans, but little is known about the mechanisms of root resorption in this condition. The purpose of this study was to investigate the mechanisms of root resorption in primary molars without successors. An animal model without permanent tooth germs was established by surgery in beagles. The times of onset of primary molar root resorption, with and without successors, were compared. The distribution of immune cells, odontoclasts, and their activating factors were determined by histochemistry and immunohistochemistry. Root resorption of primary mandibular molars without successors began later than physiological resorption. In primary molars without permanent germs, odontoclasts and immune cells were present mainly in the apical pulp at the start of root resorption, whereas in control teeth receptor activator of nuclear factor-κB ligand (RANKL)-positive cells were found mainly in the region of the periodontal ligament. CD14(+) and CD3(+) cells were found in both the pulp and the periodontal ligament region. These results suggest that the dental pulp of primary molars, as well as immune cells, may play an important role in root resorption in primary molars without permanent tooth germs.

  19. Spectrophotometric color evaluation of permanent incisors, canines and molars. A cross-sectional clinical study

    PubMed Central

    POP-CIUTRILA, IOANA-SOFIA; COLOSI, HORATIU ALEXANDRU; DUDEA, DIANA; BADEA, MANDRA EUGENIA

    2015-01-01

    Background and aims An accurate color reproduction represents the final validation level of an esthetic anterior or posterior restoration. The aim of this study was to evaluate the color of permanent maxillary incisors, canines and molars, using a clinical spectrophotometer. Methods The Vita Easyshade Advance 4.0® intraoral spectrophotometer was used by one clinician to determine the color of 369 permanent maxillary incisors, canines and molars. The best matches to Vitapan Classical® and 3D-Master® shade guides were recorded. A one-way analysis of variance and Kruskal-Wallis test were used to compare L*, a*, b*, c* and h* color coordinates among the 3 types of teeth. Differences between the mean values of all color coordinates were evaluated by use of Bonferroni corrections. Color difference (ΔE*) between incisors, canines and molars was calculated from ΔL*, Δa* and Δb* data and the results were compared to ΔE*=3.3 acceptability threshold. Results Except for Δa* and Δh* between canines and molars, statistically significant differences among the mean differences of all color coordinates were found when the 3 types of teeth were compared by pairs. The most frequently measured shades were A1 (48.4%), respectively 1M1 (31.5%) for incisors, B3 (36.6%), respectively 2M3 (39.8%) for canines and B3 (44.7%), respectively 2M3 (52%) for molars. Incisors had the highest lightness values, followed by canines and molars. Molars were the most chromatic with the highest a* and b* values. Conclusions Despite the limitations of this study, color differences among incisors, canines and molars were found to be statistically significant, above the clinical acceptability threshold established. In conclusion, successful esthetic restorations of permanent teeth of the same patient need an individual color assessment and reproduction of every type of tooth. PMID:26733753

  20. Method of making permanent magnets

    DOEpatents

    McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

    1993-09-07

    A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles. Wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties. 13 figures.

  1. Method of making permanent magnets

    DOEpatents

    McCallum, R. William; Dennis, Kevin W.; Lograsso, Barbara K.; Anderson, Iver E.

    1993-09-07

    A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties.

  2. Comparative outcome of revascularization in bilateral, non-vital, immature maxillary anterior teeth supplemented with or without platelet rich plasma: A case series.

    PubMed

    Jadhav, Ganesh Ranganath; Shah, Naseem; Logani, Ajay

    2013-11-01

    Loss of pulp vitality in an immature permanent tooth arrests root development. This leads to tooth with open apex and weak lateral dentinal walls. Management of such necrotic teeth with immature roots poses several treatment challenges. The documented study was performed to evaluate and compare apexogenesis induced by revascularization, with and without platelet rich plasma (PRP) in non-vital, immature anterior teeth. Three patients having bilateral, non-vital, immature maxillary central incisors with apical periodontitis were recruited after institutional ethical clearance. Subsequent to chemo-mechanical preparation, revascularization with and without PRP was randomly induced in either of the tooth. The cases were followed-up clinically and radiographically at 6 and 12 months. There was a marked difference in periapical healing, apical closure and dentinal wall thickening of teeth treated by revascularization with PRP.

  3. Correlation of calcification of permanent mandibular canine, mandibular premolars, and permanent mandibular first and second molars with skeletal maturity in Indian population

    PubMed Central

    Motghare, Pawan C.; Bedia, Aarti S.; Degwekar, Shirish S.; Indurkar, Atul D.; Bedia, Sumit

    2016-01-01

    Context: Morphological variation in children can be understood by the knowledge of growth and development. The state of dental development can be used in forensic odontology to ascertain the age of an unidentified child. Aims: This study aims to investigate the relationship of the stages of calcification of the permanent mandibular canine, mandibular premolars, and permanent mandibular first and second molars with skeletal maturity using panoramic and hand–wrist radiographs. Settings and Design: This descriptive work was designed as a cross-sectional study. Materials and Methods: The study was conducted on 300 healthy subjects (150 males and 150 females) ranging 7–20 years of age. Demirjian's method and Björk, Grave, and Brown's method were used to correlate teeth calcification and skeletal maturity, respectively. Statistical Analysis Used: Descriptive statistics and Spearman's rank correlation coefficient were used. Results: 1. Correlation coefficients between the skeletal maturity stages and the developmental stages of the five teeth ranged 0.461–0.877 for females and 0.480–0.790 for males. 2. The second molar showed the highest and the first molar showed the lowest relationship for female and male subjects in the Indian population. Conclusions: The findings of this study indicate that tooth calcification stages might be clinically used as a maturity indicator of the pubertal growth period. PMID:27555721

  4. Calcium biomineralization in the radular teeth of the chiton, Acanthopleura hirtosa.

    PubMed

    Evans, L A; Macey, D J; Webb, J

    1992-07-01

    A method has been devised for isolating the calcium biomineral from the iron biominerals and organic components present in the major lateral teeth of the chiton Acanthopleura hirtosa. Fourier-transform infrared spectroscopy of the calcium biomineral indicated that it was an apatite material containing carbonate and fluoride ions. Carbonate was not found to be present as a separate phase. The apatite was further separated into low and high density fractions, both of which showed crystallinity intermediate between that of bovine tibia cortical bone and human tooth enamel, as indicated by powder X-ray diffraction analysis. The calcified region of the major lateral teeth was also studied in situ using transmission electron microscopy and electron diffraction analysis, revealing a close spatial relationship between the mineral apatite phase and underlying organic matrix. It is suggested that the architectural arrangement of apatite biomineral and fibrous organic constituents imparts specialized mechanical properties to the tooth making it ideally suited for the task of obtaining food from hard surfaces.

  5. Thermographic analysis of surface damage in teeth

    NASA Astrophysics Data System (ADS)

    Conde-Contreras, M.; Bante-Guerra, J.; Hernandez-Garcia, E.; Hernandez, A. M.; Trujillo, S.; Quintana, P.; Alvarado-Gil, J. J.

    2008-02-01

    The analysis of the surface of teeth is an important field of research and technological development due to the importance of dental pieces in health and aesthetics. The presence of cracks as well as the etching effects on teeth surface, due to different chemical agents, affects not only the appearance of teeth but its integrity. In this work, laser thermography analysis of dental pieces with damage in the form of cracks is presented. The technique consists in the illumination of the surface at the center of the sample, using a 300 mW pulsed solid state laser beam focused with a gradium lens, and monitoring the spatial and temporal distribution of the temperature field. The heating of the sample is monitored using a focal plane array infrared camera, sensitive in the spectral range 7.5-13 μm with a noise equivalent temperature difference of 0.12°C. The data acquisition was performed by the PC firewire port using a PCI-8254R card and a home-made program in Labview 8.0 was used for data acquisition. The images were processed in a home-made linux program to obtain the experimental table values. Our results are compared with position and frequency scans obtained by infrared photothermal radiometry. It is shown that the crack in the tooth appears as an increase in the photothermal signal. In contrast, the thermographic image shows a more detailed structure in which close to the crack the temperature increases, but at the crack the signal falls.

  6. Comprehensive treatment of traumatic fracture and luxation injuries in the anterior permanent dentition.

    PubMed

    Blatz, M B

    2001-05-01

    The increased incidence of traumatic injuries in anterior teeth is a consequence of modern leisure activities. The key factors to successful functional and aesthetic rehabilitation of such injuries are proper diagnosis and adequate primary and subsequent treatment. In severe cases, sequential multidisciplinary treatment is required. All-ceramic crown and post-and-core systems allow for superior aesthetics without compromising function. This article addresses fractures and luxation injuries in the anterior permanent dentition and discusses updated treatment options. The multidisciplinary rehabilitation of a clinical case for optimal function and aesthetics is presented.

  7. A Compound Composite Odontoma Associated with Unerupted Permanent Incisor: A Case Report

    PubMed Central

    Das, Usha Mohan; Viswanath, Deepak; Azher, Umme

    2009-01-01

    Odontomas are the most common type of odontogenic tumors and are generally asymptomatic. Frequently they interfere with the eruption of the teeth. This is the case report of a compound composite odontoma in an 11 years old girl, which resulted in failure of eruption of the permanent maxillary right central incisor while the contralateral tooth had erupted. A calcified mass was seen in the radiograph and was provisionally diagnosed as odontoma following which the odontoma was enucleated. Routine follow-up was done for 1½ years and no recurrence was seen. PMID:25206112

  8. A study of sexual dimorphism in permanent mandibular canines and its implications in forensic investigations.

    PubMed

    Vishwakarma, N; Guha, R

    2011-06-01

    Teeth are well preserved after death and they exhibit remarkable sexual dimorphism. Hence, they provide excellent materials for forensic investigations intended for identification of sex. Present study was undertaken on permanent mandibular canines of 90 male and 90 female subjects of age group 17-23 years. The mesiodistal width for right and left mandibular canines and intercanine distance were measured. Subsequently, canine index was calculated for both sides. Significant sexual dimorphism was found in all parameters except intercanine distance. All the results were compared with previous studies and discussed in the light of genetic, evolutionary and metabolic reasons for sexual dimporhism.

  9. Clinical and radiographic diagnosis of underlying dark shadow from dentin (ICDAS 4) in permanent molars.

    PubMed

    Bertella, N; Moura, Dos S; Alves, L S; Damé-Teixeira, N; Fontanella, V; Maltz, M

    2013-01-01

    This study investigated the radiographic pattern of underlying dark shadow from dentin (ICDAS 4) in permanent molars and assessed the association between enamel breakdown and radiographic features. Ninety-five teeth (54 patients) were clinically and radiographically assessed. The majority of ICDAS 4 caries lesions presented enamel breakdown (n = 78, 82.1%) and no radiographic image (n = 64, 67.4%) or a radiolucent zone restricted to the enamel-dentin junction (n = 17, 17.9%). No association was found between enamel breakdown and radiographic features. This study suggests that a radiographic examination is needed prior to the decision making process for underlying dark shadows from dentin.

  10. Design considerations of electromagnetic force in a direct drive permanent magnet brushless motor

    NASA Astrophysics Data System (ADS)

    Chen, H. S.; Tsai, M. C.

    2008-04-01

    In this paper, a numerical study of electromagnetic force associated with the width of stator teeth, width of rotor back iron, and slot opening for a ten-pole nine-slot direct drive permanent magnet brushless motor is presented. The study calculates the amplitude of the electromagnetic force on the rotating rotor by using the finite-element method. The results show that the amplitude of electromagnetic force, which may cause the noise and vibration of motors, changes with the variation of these above mentioned three factors. The relationship between the considerations of output torque and the minimization of noise and vibration is also established in this paper.

  11. [Complications of injuries to deciduous teeth].

    PubMed

    Oka, A E; N'Cho, K J; Bakayoko-Ly, R

    2003-03-01

    The traumatisms of the temporary teeth are very frequent. They are bound to the acquirement of the march, to the games, to the sport and to the accidents of the public way. Favoured by the presence one improved proalveoly, they constitute a dental emergency of makes some important risks of complications. Indeed, these traumatisms, in case of belated conference and/or of maladjusted treatment or conducted pain, could induce some complications and have some aesthetic and functional after effects on the dental germ underlying. Some of these complications observed in some patients are stakes in evidence by some iconographic illustrations.

  12. Numerical Simulation Of Cutting Of Gear Teeth

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Huston, Ronald L.; Mavriplis, Dimitrios

    1994-01-01

    Shapes of gear teeth produced by gear cutters of specified shape simulated computationally, according to approach based on principles of differential geometry. Results of computer simulation displayed as computer graphics and/or used in analyses of design, manufacturing, and performance of gears. Applicable to both standard and non-standard gear-tooth forms. Accelerates and facilitates analysis of alternative designs of gears and cutters. Simulation extended to study generation of surfaces other than gears. Applied to cams, bearings, and surfaces of arbitrary rolling elements as well as to gears. Possible to develop analogous procedures for simulating manufacture of skin surfaces like automobile fenders, airfoils, and ship hulls.

  13. High-performance permanent magnets.

    PubMed

    Goll, D; Kronmüller, H

    2000-10-01

    High-performance permanent magnets (pms) are based on compounds with outstanding intrinsic magnetic properties as well as on optimized microstructures and alloy compositions. The most powerful pm materials at present are RE-TM intermetallic alloys which derive their exceptional magnetic properties from the favourable combination of rare earth metals (RE = Nd, Pr, Sm) with transition metals (TM = Fe, Co), in particular magnets based on (Nd.Pr)2Fe14B and Sm2(Co,Cu,Fe,Zr)17. Their development during the last 20 years has involved a dramatic improvement in their performance by a factor of > 15 compared with conventional ferrite pms therefore contributing positively to the ever-increasing demand for pms in many (including new) application fields, to the extent that RE-TM pms now account for nearly half of the worldwide market. This review article first gives a brief introduction to the basics of ferromagnetism to confer an insight into the variety of (permanent) magnets, their manufacture and application fields. We then examine the rather complex relationship between the microstructure and the magnetic properties for the two highest-performance and most promising pm materials mentioned. By using numerical micromagnetic simulations on the basis of the Finite Element technique the correlation can be quantitatively predicted, thus providing a powerful tool for the further development of optimized high-performance pms.

  14. High-performance permanent magnets

    NASA Astrophysics Data System (ADS)

    Goll, D.; Kronmüller, H.

    High-performance permanent magnets (pms) are based on compounds with outstanding intrinsic magnetic properties as well as on optimized microstructures and alloy compositions. The most powerful pm materials at present are RE-TM intermetallic alloys which derive their exceptional magnetic properties from the favourable combination of rare earth metals (RE=Nd, Pr, Sm) with transition metals (TM=Fe, Co), in particular magnets based on (Nd,Pr)2Fe14B and Sm2(Co,Cu,Fe,Zr)17. Their development during the last 20 years has involved a dramatic improvement in their performance by a factor of >15 compared with conventional ferrite pms therefore contributing positively to the ever-increasing demand for pms in many (including new) application fields, to the extent that RE-TM pms now account for nearly half of the worldwide market. This review article first gives a brief introduction to the basics of ferromagnetism to confer an insight into the variety of (permanent) magnets, their manufacture and application fields. We then examine the rather complex relationship between the microstructure and the magnetic properties for the two highest-performance and most promising pm materials mentioned. By using numerical micromagnetic simulations on the basis of the Finite Element technique the correlation can be quantitatively predicted, thus providing a powerful tool for the further development of optimized high-performance pms.

  15. Longitudinal clinical and radiographic evaluation of severely intruded permanent incisors in a pediatric population.

    PubMed

    Neto, José Jeová Siebra Moreira; Gondim, Juliana Oliveira; de Carvalho, Fernanda Matias; Giro, Elisa Maria Aparecida

    2009-10-01

    Intrusion is defined as the axial dislodgment of the tooth into its socket and is considered one of the most severe types of dental trauma. This longitudinal outcome study was undertaken to evaluate clinically and radiographically severely intruded permanent incisors in a population of children and adolescents. All cases were treated between September 2003 and February 2008 in a dental trauma service. Clinical and radiographic data were collected from 12 patients (eight males and four females) that represented 15 permanent maxillary incisors. Mean age at the time of injury was 8 years and 9 months (range 7-14 years and 8 months). Mean time elapsed to follow-up was 26.6 months (range 10-51 months). The analysis of data showed that tooth intrusion was twice as frequent in males. The maxillary central incisors were the most commonly intruded teeth (93.3%), and falling at home was the main etiologic factor (60%). More than half of the cases (53.3%) were multiple intrusions, 73.3% of the intruded teeth had incomplete root formation and 66.6% of the teeth suffered other injuries concomitant to intrusion. Immediate surgical repositioning was the treatment of choice in 66.7% of the cases, while watchful waiting for the tooth to return to its pre-injury position was adopted in 33.3% of the cases. The teeth that suffered additional injuries to the intrusive luxation presented a fivefold increased relative risk of developing pulp necrosis. The immature teeth had six times more chances of presenting pulp canal obliteration that the mature teeth and a lower risk of developing root resorption. The most frequent post-injury complications were pulp necrosis (73.3%), marginal bone loss (60%), inflammatory root resorption (40%), pulp canal obliteration (26.7%) and replacement root resorption (20%). From the results of this study, it was not possible to determine whether the type immediate treatment had any influence on the appearance of sequelae like pulp necrosis and root

  16. Histological appearance of postmortem pink teeth: Report of two cases.

    PubMed

    Gowda, Bk Charan; Sivapathasundharam, B; Chatterji, Ananjan; Chatterji, B L

    2015-01-01

    This article presents images and histological changes in the dentin of two cases involving posmortem pink teeth. Postmortem pink teeth were noted among two deceased male individuals. Pink teeth were noted during autopsy examination after twelve days in one corpse, and eight days following death in the second case. During the examination decomposition and putrefaction of the body was noted. Cause of death was drowning in one case and haemorrhages and shock in another. A central incisor tooth was obtained from each body. Both teeth exhibited a pink appearance and the intensity was more pronounced in the cervical region. Although pink teeth can be noted in death due to asphyxia, carbon monoxide poisoning and so on, it is necessary to study the exact role behind the appearance of pink teeth and try to incorporate the finding medico legally.

  17. Coronal reconstruction following anterior teeth traumatism: multidisciplinary treatment.

    PubMed

    Cohen-Carneiro, Flavio; Sponchiado, Emilio Carlos; Garcia, Lucas do Fonseca Roberti; Yurtsever, Fikriye Viga; Pontes, Danielson Guedes; Sena, Amilen

    2013-08-01

    This study describes how periodontology, endodontology, and dentistry were integrated for the coronal reconstruction of anterior teeth extensively destroyed by dental trauma. A 15-year-old girl suffered a bicycle accident that resulted in the fracture of teeth No. 8 and 9. Clinical and radiographic examinations confirmed coronal fracture in both teeth, in addition to compromised pulp vitality, invasion of the biologic periodontal space, and loss of coronal space due to mesialization of the neighboring teeth. The protocol consisted of endodontic treatment for the fractured teeth, periodontal surgery to augment the clinical crown and gingival recontouring, intracanal cementation of esthetic glass fiber posts, and coronal reconstruction with resin composite. At a longitudinal follow-up visit 1 year later, clinical and radiographic examinations revealed successful rehabilitation of the fractured teeth.

  18. Characteristics of stem cells from human exfoliated deciduous teeth (SHED) from intact cryopreserved deciduous teeth.

    PubMed

    Lee, Hyo-Seol; Jeon, Mijeong; Jeon, Mi Jung; Kim, Seong-Oh; Kim, Seung-Hye; Lee, Jae-Ho; Lee, Jea-Ho; Ahn, Su-Jin; Shin, Yooseok; Song, Je Seon

    2015-12-01

    The aim of this study is to compare the characteristics of stem cells derived from human exfoliated deciduous teeth (SHED) from cryopreserved intact deciduous teeth with those of fresh SHED. In total, 20 exfoliated deciduous teeth were randomly divided into a fresh group (f-SHED; n = 11) and cryopreserved group (c-SHED; n = 9; stored for 1-8 months). Following thawing and separation of the pulp, the SHED cells were cultured, and the characteristics as mesenchymal stem cells were investigated using proliferation assays, cell-cycle analysis, colony-forming unit-fibroblast (CFU-F) assays, and flow cytometry analyses. Furthermore, differentiation into adipogenic and osteogenic lineages was investigated in vitro as well as in vivo via transplantation in mice. We found no significant differences between the two groups in the proliferation analyses, in the expression of mesenchymal stem cell markers, or in the adipogenic and osteogenic differentiation in vitro (p < 0.05). Furthermore, the in vivo transplantation results showed no significant differences in the quantity of bone tissue that formed or in histochemistry performance (p < 0.05). In conclusion, cryopreservation of intact exfoliated deciduous teeth appears to be a useful method for preserving SHED.

  19. Inhibition of rat and bovine trypsins and chymotrypsins by soybean, bovine basic pancreatic, and bovine colostrum trypsin inhibitors.

    PubMed

    Esparza, I; Brock, J H

    1978-01-01

    1. Bovine (Bos taurus) trypsin and trypsin activity in rat (Rattus norvegicus) pancreatic extract were inhibited by soybean trypsin inhibitor and by bovine basic pancreatic and colostrum inhibitors. 2. Bovine alpha-chymotrypsin was inhibited by soybean and bovine basic pancreatic inhibitors but only weakly by colostrum inhibitor. 3. Chymotrypsin activity in rat pancreatic extract was due to at least three different components against all of which the inhibitors were largely ineffective. 4. It is concluded that bovine colostrum inhibitor has a more limited inhibition spectrum than the phylogenetically related basic pancreatic inhibitor which, in turn, is less active against rat than against bovine enzymes.

  20. [Professional teeth cleaning is more than plaque removal].

    PubMed

    van Foreest, Andries

    2006-12-15

    Telephone enquiries about the cost of cleaning the teeth of cats or dogs cannot be answered without clinical investigation of the animal and oral examination under sedation or anaesthesia. This article describes the procedures used during the professional cleaning of the teeth of companion animals. An itemized list of procedures and their cost means that the era of "shopping around" for teeth cleaning is past.

  1. Root Canal Morphology of Mandibular First Permanent Molars in an Indian Population

    PubMed Central

    Chourasia, Hemant Ramesh; Meshram, Ganesh K.; Warhadpande, Manjusha; Dakshindas, Darshan

    2012-01-01

    An in vitro study was performed to determine the number of roots, root canals per tooth, root canal configurations, and frequency of isthmi and apical deltas in mandibular first permanent molars in an Indian population. Hundred and fifty mandibular first permanent molars were collected and subjected to clearing technique. The cleared teeth were examined in a stereomicroscope under 7.5x magnifications. The canal configurations were categorized using Vertucci's classification. Overall 94.6% of the mandibular first molars had two roots, and 5.3% had extradistal roots (distolingual root). In addition, 64% of the specimens had three root canals, and 36% had four root canals. The most common canal configurations of mesial and distal roots were Vertucci type IV (54%) and type I (65.3%), respectively. Clinician should be aware of the complex root canal morphology of mandibular first molars among the Indian population before and during the root canal treatment. PMID:22287965

  2. Root Canal Morphology of Permanent Maxillary and Mandibular Canines in Indian Population Using Cone Beam Computed Tomography

    PubMed Central

    Somalinga Amardeep, Nikhita; Raghu, Sandhya; Natanasabapathy, Velmurugan

    2014-01-01

    Aim. To investigate the root canal anatomy of single-rooted permanent maxillary and mandibular canines in an Indian population using cone beam computed tomography (CBCT). Methodology. A total of 250 permanent maxillary canines and 250 permanent mandibular canines were selected and scanned using CBCT. The root anatomy of each tooth was evaluated for the following parameters: the pattern of the root canals, anatomic length of the crown and the root, the presence of accessory canals, the shape of the access cavity, the position of the apical foramina, root diameter, and dentin thickness of the root. Results. Majority of the teeth had a Type I canal configuration in both maxillary canines (81.6%) and mandibular canines (79.6%). In maxillary canine the other canal patterns found were Type III (11.6%), Type II (2.8%), Type V (2%), Type XIX (1.2%), and Type IV (0.8%). In mandibular canines the various other canal patterns found were Type III (13.6%), Type II (3.2%), Type V (2%), and Type XIX (1.6%). Apical foramina were laterally positioned in the majority of the teeth, 70.4% and 65.6% in maxillary and mandibular canines, respectively. 12% of the maxillary canines and 12.8% of the mandibular canines had accessory canals. Conclusion. The root canal anatomy of permanent maxillary and mandibular canines varied widely in an Indian population. PMID:24895538

  3. The bleaching efficiency of KTP and diode 810 nm lasers on teeth stained with different substances: An in vitro study.

    PubMed Central

    Lagori, G; Vescovi, P; Merigo, E; Meleti, M.; Fornaini, C

    2014-01-01

    Background and aims: The purpose of this study was to evaluate the bleaching efficiency of two different lasers (KTP and diode 810 nm) on teeth, randomly divided by means an Excel function (Microsoft Excel 2010 “Fx causale”) and stored in physiological solution, that were previously stained with different substances commonly considered as a cause of tooth discoloration, such as coffee, tea and red fruits and to investigate the role of laser irradiation in an experimental model, during the dental bleaching process. Methods: Three groups of 45 bovine teeth were created and immersed for one week in a solution of tea, coffee or red fruits respectively. Each group was divided into three sub-groups of fifteen teeth. One was bleached with a 30% hydrogen peroxide gel for 30 min only as control, another 15 teeth group was bleached with the gel plus 810 nm diode laser irradiation and the last group was bleached with the gel plus KTP irradiation. The lasers were applied in three cycles of 30 sec each with a power of 1.5 W localized on a 10 mm spot on the teeth. The temperature of the gel was checked during the bleaching procedure using a thermometer and the colour of each tooth was measured by a spectrophotometer. Results: Statistical analysis of the collected data was performed using Graph Pad Prism, version 6.01 software, Kruskal-Wallis test and Dunn's multiple comparison test and Mann-Whitney test. P value <0.0001 was considered extremely significant (***), P value between 0.001 to 0.01 very significant (**), P value between 0.01 to 0.05 significant (*) and P value >0.05 not significant (ns). By these tests diode laser was effective only at bleaching teeth stained with coffee meanwhile the KTP laser was efficient at bleaching teeth with coffee, tea and red fruits stains. Conclusion: This study suggests that a relation between the laser wavelength and the type of staining on the dental enamel and the efficacy of the whitening treatment exists. PMID:24771968

  4. Restoring primary anterior teeth: updated for 2014.

    PubMed

    Waggoner, William F

    2015-01-01

    The purpose of this paper was to review the current literature associated with the techniques and materials for the restoration of primary anterior teeth and make clinical recommendations based upon the available literature. A variety of esthetic restorative materials are available to utilize for restoring primary incisors. Awareness of the specific strengths, weakness, and properties of each material can enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and crowns that are luted onto the tooth and are either some type of stainless steel or zirconia crown. There is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. Operator preferences, esthetic demands by parents, the child's behavior, the amount of tooth structure remaining, and moisture and hemorrhage control are all variables that affect the decision and ultimate outcome of whatever restorative solution is chosen.

  5. Applying tribology to teeth of hoofed mammals.

    PubMed

    Schulz, Ellen; Calandra, Ivan; Kaiser, Thomas M

    2010-01-01

    Mammals inhabit all types of environments and have evolved chewing systems capable of processing a huge variety of structurally diverse food components. Surface textures of cheek teeth should thus reflect the mechanisms of wear as well as the functional traits involved. We employed surface textures parameters from ISO/DIS 25178 and scale-sensitive fractal analysis (SSFA) to quantify dental wear in herbivorous mammals at the level of an individual wear enamel facet. We evaluated cheek dentitions of two grazing ungulates: the Blue Wildebeest (Connochaetes taurinus) and the Grevy's Zebra (Equus grevyi). Both inhabit the east African grassland savanna habitat, but they belong to fundamentally different taxonomic units. We tested the hypothesis that the foregut fermenting wildebeest and the hindgut fermenting zebra show functional traits in their dentitions that relate to their specific mode of food-composition processing and digestion. In general, surface texture parameters from SSFA as well as ISO/DIS 25178 indicated that individual enamel ridges acting as crushing blades and individual wear facets of upper cheek teeth are significantly different in surface textures in the zebra when compared with the wildebeest. We interpreted the complexity and anisotropy signals to be clearly related to the brittle, dry grass component in the diet of the zebra, unlike the wildebeest, which ingests a more heterogeneous diet including fresh grass and herbs. Thus, SSFA and ISO parameters allow distinctions within the subtle dietary strategies that evolved in herbivorous ungulates with fundamentally different systematic affinities but which exploit a similar dietary niche.

  6. Soft dentin results in unique flexible teeth in scraping catfishes.

    PubMed

    Geerinckx, Tom; Huysseune, Ann; Boone, Matthieu; Claeys, Myriam; Couvreur, Marjolein; De Kegel, Barbara; Mast, Peter; Van Hoorebeke, Luc; Verbeken, Kim; Adriaens, Dominique

    2012-01-01

    Teeth are generally used for actions in which they experience mainly compressive forces acting toward the base. The ordered tooth enamel(oid) and dentin structures contribute to the high compressive strength but also to the minor shear and tensile strengths. Some vertebrates, however, use their teeth for scraping, with teeth experiencing forces directed mostly normal to their long axis. Some scraping suckermouth catfishes (Loricariidae) even appear to have flexible teeth, which have not been found in any other vertebrate taxon. Considering the mineralized nature of tooth tissues, the notion of flexible teeth seems paradoxical. We studied teeth of five species, testing and measuring tooth flexibility, and investigating tooth (micro)structure using transmission electron microscopy, staining, computed tomography scanning, and scanning electron microscopy-energy-dispersive spectrometry. We quantified the extreme bending capacity of single teeth (up to 180°) and show that reorganizations of the tooth (micro)structure and extreme hypomineralization of the dentin are adaptations preventing breaking by allowing flexibility. Tooth shape and internal structure appear to be optimized for bending in one direction, which is expected to occur frequently when feeding (scraping) under natural conditions. Not all loricariid catfishes possess flexible teeth, with the trait potentially having evolved more than once. Flexible teeth surely rank among the most extreme evolutionary novelties in known mineralized biological materials and might yield a better understanding of the processes of dentin formation and (hypo)mineralization in vertebrates, including humans.

  7. Premature loss of primary anterior teeth due to trauma--potential short- and long-term sequelae.

    PubMed

    Holan, Gideon; Needleman, Howard L

    2014-04-01

    Traumatic dental injuries (TDIs) can result in the premature loss of primary anterior teeth due to an immediate avulsion, extraction later after the injury because of poor prognosis or late complications, or early exfoliation. There are a number of potential considerations or sequelae as a result of this premature loss that have been cited in the dental literature, which include esthetics, quality of life, eating, speech development, arch integrity (space loss), development and eruption of the permanent successors, and development of oral habits. This article provides a comprehensive review of the dental literature on the possible consequences of premature loss of maxillary primary incisors following TDI.

  8. Occurrence of dental caries in primary and permanent dentition, oral health status and treatment needs among 12-15 year old school children of Jorpati VDC, Kathmandu.

    PubMed

    Shrestha, N; Acharya, J; Sagtani, A R; Shrestha, R; Shrestha, S

    2014-12-01

    Dental caries occurrence, distribution, oral health status and corresponding treatment needs in 12 - 15 year old children are useful tools for evaluation of oral health. Dental caries status along with its treatment needs was recorded according to World Health Organization (WHO) index (1997) in 366 children from five schools within Jorpati Village Development Committee (VDC), Kathmandu. Dental caries was diagnosed in 156 (42.6%) children, out of which 122 (78.21%) had caries in permanent teeth, 26 (16.67%) had caries in primary teeth, and 8 (5.13%) had caries in both dentition. The age wise distribution of dental caries showed the highest prevalence among 12 year old students (23.8%) and the lowest among 15 year olds (3.8%). Among the female students (177), 43.5% showed presence of dental caries, while the prevalence among male students (179) was 41.8%.Out of the total number of teeth affected by dental caries (336), 273 (81.25%) were permanent teeth and 63 (18.75%) were primary teeth. The intra arch distribution of dental caries in permanent as well as primary dentition was statistically significant (P < 0.05). Restorative treatment (89.38%) was the main need in permanent dentition, and endodontic treatment (60.32%) in primary dentition. Chronologic enamel hypoplasia was found in 14 (3.83%) of the total population, and 62 (16.94%) required oral prophylaxis. These findings are significant as they can initiate further research in this area, which may help establish reliable baseline data for implementation of preventive oral health programs.

  9. Influence of ferrule preparation with or without glass fiber post on fracture resistance of endodontically treated teeth

    PubMed Central

    de LIMA, Alexandra Furtado; SPAZZIN, Aloísio Oro; GALAFASSI, Daniel; CORRER-SOBRINHO, Lourenço; CARLINI-JÚNIOR, Bruno

    2010-01-01

    Objective This study evaluated the effect of ferrule preparation (Fp) on the fracture resistance of endodontically treated teeth, restored with composite resin cores with or without glass fiber posts. Material and Methods Forty-four bovine teeth were sectioned 19 or 17 mm (2 mm ferrule) from the apex, endodontically treated and assigned to four groups (n = 11): Group 1: Fp and post; Group 2: Fp and without post; Group 3: without Fp and with post; Group 4: without Fp and without post. All specimens were restored with composite resin core and metal crown. Specimens were subjected to fracture resistance testing in a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey’s tests (α=0.05). Results The mean fracture resistance values were as follows: Group 1: 573.3 N; Group 2: 552.5 N; Group 3: 275.3 N; Group 4: 258.6 N. Significantly higher fracture resistance was found for the groups with Fp (p<0.001). Conclusion There was no statistically significant interaction between the "Fp" and "post" factors (p = 0.954). The ferrule preparation increased the fracture resistance of endodontically treated teeth. However, the use of glass fiber post showed no significant influence on the fracture resistance. PMID:20835570

  10. In vitro assessment of a gel base containing 2% chlorhexidine as a sodium perborate's vehicle for intracoronal bleaching of discolored teeth.

    PubMed

    Oliveira, Daniel Pinto de; Gomes, Brenda Paula Figueiredo de Almeida; Zaia, Alexandre Augusto; Souza-Filho, Francisco José de; Ferraz, Caio Cezar Randi

    2006-07-01

    The purpose of this study was to assess a gel base containing 2% chlorhexidine (CHX) as a vehicle to be mixed with sodium perborate for intracoronal bleaching of discolored teeth, comparing its bleaching efficacy to sodium perborate mixed with other vehicles; 37% carbamide peroxide and 30% hydrogen peroxide. There were 110 fresh bovine incisors artificially stained using whole blood. The samples were divided into 11 groups and the intracoronal bleaching was performed using the "walking bleach technique". The bleaching agents were replaced three times at 7-day intervals. Using digital photos and a shade guide created for bovine teeth, the samples were evaluated at day 0, 7, 14, 21, and 28. On evaluation day, the photos were examined by three endodontists giving scores from 1 to 5 based on the shade guide created. Data were analyzed statistically by Kruskall-Wallis test. After 28 days, all evaluated teeth received scores that were statistically similar. Groups that used sodium perborate and a liquid vehicle bleached faster than those that used a gel based vehicle. The CHX gel allowed dissociation for the bleaching agent. The 2% CHX gel exhibited a good potential for use as a vehicle for sodium perborate or as a complement for carbamide peroxide.

  11. The gothic arch tracing and the upper canine teeth as guides in the positioning of upper posterior teeth.

    PubMed

    el-Gheriani, A S; Davies, A L; Winstanley, R B

    1989-09-01

    The relationship between the position of the buccal cusps of the natural upper posterior teeth and the distance between the lateral arms of the Gothic arch tracing or the distance between the upper canine teeth has been found to be constant to within +/- 2 mm. This may be of value when setting up artificial teeth for denture patients, enabling them to be positioned close to the natural predecessors.

  12. New permanent magnets; manganese compounds.

    PubMed

    Coey, J M D

    2014-02-12

    The exponential growth of maximum energy product that prevailed in the 20th century has stalled, leaving a market dominated by two permanent magnet materials, Nd2Fe14B and Ba(Sr)Fe12O19, for which the maximum theoretical energy products differ by an order of magnitude (515 kJ m(-3) and 45 kJ m(-3), respectively). Rather than seeking to improve on optimized Nd-Fe-B, it is suggested that some research efforts should be devoted to developing appropriately priced alternatives with energy products in the range 100-300 kJ m(-3). The prospects for Mn-based hard magnetic materials are discussed, based on known Mn-based compounds with the tetragonal L10 or D022 structure or the hexagonal B81 structure.

  13. Is CO2 ice permanent?

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1992-01-01

    Carbon dioxide ice has been inferred to exist at the south pole in summertime, but Earth based measurements in 1969 of water vapor in the Martian atmosphere suggest that all CO2 ice sublined from the southern polar cap and exposed underlying water ice. This implies that the observed summertime CO2 ice is of recent origin. It appears possible to construct an energy balance model that maintains seasonal CO2 ice at the south pole year round and still reasonably simulates the polar cap regression and atmospheric pressure data. This implies that the CO2 ice observed in the summertime south polar cap could be seasonal in origin, and that minor changes in climate could cause CO2 ice to completely vanish, as would appear to have happened in 1969. However, further research remains before it is certain whether the CO2 ice observed in the summertime south polar cap is seasonal or is part of a permanent reservoir.

  14. Storage media for avulsed teeth: a literature review.

    PubMed

    Poi, Wilson Roberto; Sonoda, Celso Koogi; Martins, Christine Men; Melo, Moriel Evangelista; Pellizzer, Eduardo Pizza; de Mendonça, Marcos Rogério; Panzarini, Sônia Regina

    2013-01-01

    wide array of types of wet storage media have been evaluated in laboratory studies and clinical reports, including cell and tissue culture solutions like Hank's Balanced Salt Solution (HBSS); medical/hospital products developed specifically for organ storage purposes, such as Viaspan® and Euro-Collins®; culture media, like Minimum Essential Medium (MEM); saline; natural products like water, saliva, bovine milk and its variations, propolis, green tea, Morus rubra (red mulberry), egg white and coconut water; rehydrating solutions, like Gatorade® and Ricetral, and even contact lens solutions. Based on the literature, it could be stated that, so far, apart from Based on the literature, it could be stated that, so far, apart from solutions designed specifically for storage and culture purposes, regular pasteurized whole milk is the most frequently recommended and with the best prognosis among other solutions that are likely to be available at the scene of an accident, such as water, saline or saliva. Its advantages include its high availability, ready accessibility, physiologically compatible pH and osmolality (fluid pressure) with the root-surface adhered PDL cells, presence of nutrients and growth factors. However, there is not yet a single solution that fulfills all requirements to be considered as the ideal medium for temporary storage of avulsed teeth, and research on this field should carry on.

  15. Vaccination against bovine babesiosis.

    PubMed

    De Vos, A J; Bock, R E

    2000-01-01

    Bovine babesiosis is an important disease caused by Babesia bovis, B. bigemina, and B. divergens. Solid immunity develops after infection and this feature has been exploited with the use of live attenuated organisms as immunogens. Attributes of live vaccines include a durable immunity to heterologous challenge after one vaccination. To overcome disadvantages relating to poor quality control (risk of contamination and adverse reactions), production procedures have been modified to meet the requirements of codes of good manufacturing practice. This includes development of methods to allow production of cryopreserved vaccine and limit antigenic drift. Killed vaccines have also been used on a limited basis and consist of antigens extracted from cultured material or blood of infected calves, and given with adjuvant. The degree and duration of immunity against heterologous challenge is not well documented. Attempts are being made to develop subunit vaccines but the progress has been slow. A better understanding of the mechanisms involved in the expression of protective immunity against Babesia spp will aid in the identification of protective antigens.

  16. Pathology of bovine tuberculosis.

    PubMed

    Domingo, M; Vidal, E; Marco, A

    2014-10-01

    Bovine tuberculosis (bTB) is a chronic granulomatous caseous-necrotising inflammatory process that mainly affects the lungs and their draining lymph nodes (Ln.). The pathological changes associated with bTB infection reflect the interplay between the host defence mechanisms and the mycobacterial virulence factors and the balance between the immunologic protective responses and the damaging inflammatory processes. Inhalation is the most common infection route and causes lesions of the nasopharynx and lower respiratory tract, including its associated lymph nodes. The initial infection (primary complex) may be followed by chronic (post-primary) tuberculosis or may be generalised. Goat tuberculosis often produces liquefactive necrosis and caverns, similarly to human TB. The assessment of the severity of TB lesions is crucial for vaccine trials. Semi-quantitative gross lesion scoring systems have been developed for cattle, but imaging technology has allowed the development of more standardised, objective, and quantitative methods, such as multi-detector computed tomography (MDCT), which provides quantitative measures of lesion volume.

  17. Accessing Developmental Information of Fossil Hominin Teeth Using New Synchrotron Microtomography-Based Visualization Techniques of Dental Surfaces and Interfaces

    PubMed Central

    Le Cabec, Adeline; Tang, Nancy; Tafforeau, Paul

    2015-01-01

    Quantification of dental long-period growth lines (Retzius lines in enamel and Andresen lines in dentine) and matching of stress patterns (internal accentuated lines and hypoplasias) are used in determining crown formation time and age at death in juvenile fossil hominins. They yield the chronology employed for inferences of life history. Synchrotron virtual histology has been demonstrated as a non-destructive alternative to conventional invasive approaches. Nevertheless, fossil teeth are sometimes poorly preserved or physically inaccessible, preventing observation of the external expression of incremental lines (perikymata and periradicular bands). Here we present a new approach combining synchrotron virtual histology and high quality three-dimensional rendering of dental surfaces and internal interfaces. We illustrate this approach with seventeen permanent fossil hominin teeth. The outer enamel surface and enamel-dentine junction (EDJ) were segmented by capturing the phase contrast fringes at the structural interfaces. Three-dimensional models were rendered with Phong’s algorithm, and a combination of directional colored lights to enhance surface topography and the pattern of subtle variations in tissue density. The process reveals perikymata and linear enamel hypoplasias on the entire crown surface, including unerupted teeth. Using this method, highly detailed stress patterns at the EDJ allow precise matching of teeth within an individual’s dentition when virtual histology is not sufficient. We highlight that taphonomical altered enamel can in particular cases yield artificial subdivisions of perikymata when imaged using X-ray microtomography with insufficient resolution. This may complicate assessments of developmental time, although this can be circumvented by a careful analysis of external and internal structures in parallel. We further present new crown formation times for two unerupted canines from South African Australopiths, which were found to form

  18. Effect of Er:YAG Laser on Shear Bond Strength of Composite to Enamel and Dentin of Primary Teeth

    PubMed Central

    Bahrololoomi, Zahra; Kabudan, Mona; Gholami, Leila

    2015-01-01

    Objectives: Bond strength of composite resin to enamel and dentin of primary teeth is lower than that to permanent teeth; therefore, it may compromise the adhesive bonding. New methods, such as laser application have been recently introduced for tooth preparation. The purpose of this study was to evaluate the effect of tooth preparation with bur and Er:YAG laser on shear bond strength of composite to enamel and dentin of primary teeth. Materials and Methods: Seventy-five primary molar teeth were collected and 150 specimens were obtained by mesiodistal sectioning of each tooth. In each of the enamel and dentin groups, the teeth were randomly assigned to 3 subgroups with the following preparations: bur preparation + etching (37% H3PO4), laser preparation + etching, and laser preparation without etching. Single Bond adhesive and Z250 composite were applied to all samples. After thermocycling, the shear bond strength testing was preformed using the Instron Testing Machine. Data were analysed using SPSS-17 and two-way ANOVA. Results: The bond strength of enamel specimens was significantly higher than that of dentin specimens, except for the laser-non-etched groups. The enamel and dentin laser-non-etched groups had no significant difference in bond strength. In both enamel and dentin groups, bur preparation + etching yielded the highest bond strength, followed by laser preparation + etching, and the laser preparation without etching yielded the lowest bond strength (P < 0.001). Conclusion: In both enamel and dentin groups, laser preparation caused lower shear bond strength compared to bur preparation. PMID:26622267

  19. Accessing developmental information of fossil hominin teeth using new synchrotron microtomography-based visualization techniques of dental surfaces and interfaces.

    PubMed

    Le Cabec, Adeline; Tang, Nancy; Tafforeau, Paul

    2015-01-01

    Quantification of dental long-period growth lines (Retzius lines in enamel and Andresen lines in dentine) and matching of stress patterns (internal accentuated lines and hypoplasias) are used in determining crown formation time and age at death in juvenile fossil hominins. They yield the chronology employed for inferences of life history. Synchrotron virtual histology has been demonstrated as a non-destructive alternative to conventional invasive approaches. Nevertheless, fossil teeth are sometimes poorly preserved or physically inaccessible, preventing observation of the external expression of incremental lines (perikymata and periradicular bands). Here we present a new approach combining synchrotron virtual histology and high quality three-dimensional rendering of dental surfaces and internal interfaces. We illustrate this approach with seventeen permanent fossil hominin teeth. The outer enamel surface and enamel-dentine junction (EDJ) were segmented by capturing the phase contrast fringes at the structural interfaces. Three-dimensional models were rendered with Phong's algorithm, and a combination of directional colored lights to enhance surface topography and the pattern of subtle variations in tissue density. The process reveals perikymata and linear enamel hypoplasias on the entire crown surface, including unerupted teeth. Using this method, highly detailed stress patterns at the EDJ allow precise matching of teeth within an individual's dentition when virtual histology is not sufficient. We highlight that taphonomical altered enamel can in particular cases yield artificial subdivisions of perikymata when imaged using X-ray microtomography with insufficient resolution. This may complicate assessments of developmental time, although this can be circumvented by a careful analysis of external and internal structures in parallel. We further present new crown formation times for two unerupted canines from South African Australopiths, which were found to form over

  20. Evaluation of antimicrobial efficacy of various root canal filling materials used in primary teeth: a microbiological study.

    PubMed

    Reddy, S; Ramakrishna, Y

    2007-01-01

    The primary goal of endodontic treatment in primary teeth is to eliminate infection, and to retain the tooth in a functional state until their nornal exfoliation time without endangering the permanent dentition or the general health of the child. The complexity of the pulp canal system in primary teeth presents a discerning problem for chemo-mechanical preparation. One of the factors determining the success of endodontic treatment in infected primary teeth is the sealing material that should encompass among other factors a potent bactericidal effect and the capacity to resorb along with the roots of primary teeth. This study evaluated the antimicrobial effectiveness of 5 root canal filing materials and a negative control agent against 23 strains of bacteria isolated from infected root canals of primary molar teeth and 3 non standard bacterial strains using agar diffusion assay. The materials were Zinc oxide and Eugenol (ZOE), Zinc oxide-Eugenol and Formocresol (ZOE+FC), Calcium hydroxide and sterile water (CAOH+H2O), Zinc oxide and Camphorated phenol (ZO+CP), Calcium hydroxide and Iodoform (Metapex) and Vaseline (Control). All the materials except Vaseline showed varied antimicrobial activity against the test bacteria. The zones of inhibition were ranked into 4 inhibition categories based on the proportional distribution of the data. All the 26 bacterial isolates were classified under 4 groups based on Aerobic/Anaerobic and Gram positive/Gram negative. Statistical analysis was carried out to compare the antimicrobial effectiveness between materials tested with each of the bacterial groupings. ZOE+FC produced strong inhibtion against most bacteria when compared to ZOE, ZO+CP and CAOH+H2O. Metapex and Vaseline were found to be non inhibitory

  1. Long-Term Fracture Resistance of Simulated Immature Teeth Filled with Various Calcium Silicate-Based Materials

    PubMed Central

    Dincol, M. Emir; Ozel, Emre; Yilmaz, Bulent; Aktoren, Oya

    2016-01-01

    Objective. The aim of this in vitro study was to evaluate the long-term fracture resistance of simulated human immature permanent teeth filled with BioAggregate™ (BA), mineral trioxide aggregate (MTA), and EndoSequence® Root Repair Material (ERRM). Material and Methods. 40 teeth, simulated to average root length of 13 ± 1 mm (Cvek's stage 3), were included in the study. The teeth were randomly divided into four groups: Group 1: DiaRoot® BA, Group 2: MTA-Plus™ (MTA-P), Group 3: MTA-Angelus (MTA-A), and Group 4: ERRM. The root canal filling materials were applied according to the manufacturers' instructions. After 24 months of incubation, the roots of the teeth were embedded in acrylic blocks and subjected to fracture testing. The resultant data were analyzed statistically by Kruskal-Wallis and Mann-Whitney U tests. Results. Mean (±SD) failure loads (MPa) were 20.46 ± 2.53 for BA, 18.88 ± 5.13 for MTA-P, 14.12 ± 1.99 for MTA-A, and 17.65 ± 4.28 for ERRM groups. BA group exhibited the highest and MTA-A group showed the lowest resistance to fracture. Significant differences in fracture resistance were found between the groups of BA and MTA-A (p < 0.001), MTA-P and MTA-A (p < 0.05), and ERRM and MTA-A (p < 0.05). Conclusion. Within the limitations of this study, data suggests that BA-filled immature teeth demonstrate higher fracture resistance than other groups at 24 months appearing to be the most promising material tested. PMID:27382564

  2. Permanence of Stochastic Lotka-Volterra Systems

    NASA Astrophysics Data System (ADS)

    Liu, Meng; Fan, Meng

    2017-04-01

    This paper proposes a new definition of permanence for stochastic population models, which overcomes some limitations and deficiency of the existing ones. Then, we explore the permanence of two-dimensional stochastic Lotka-Volterra systems in a general setting, which models several different interactions between two species such as cooperation, competition, and predation. Sharp sufficient criteria are established with the help of the Lyapunov direct method and some new techniques. This study reveals that the stochastic noises play an essential role in the permanence and characterize the systems being permanent or not.

  3. Management of fused supernumerary teeth in children using guided tissue regeneration: long-term follow up of 2 cases.

    PubMed

    Olsen, Christopher B; Johnston, Timothy; Desai, Mala; Peake, Gregory G

    2002-01-01

    Surgical separation of supernumerary teeth fused to permanent incisor teethhas typically given rise to residual post surgical periodontal defects, induding loss of attachment and deep periodontal pocketing with persistent inflammation. Other complications include devitalisation of the retained tooth section, ankylosis, external and replacement resorption. A unique technique of using guided tissue regeneration has been successfully employed to promote periodontal healing, after 2 cases of surgical removal of a supernumerary tooth fused to a permanent maxillary lateral incisor tooth. In the first case, a 2-stage guided tissue regeneration technique was completed with a nonresorbable Gor-Tex membrane, and was followed up after 9 years. The second case was completed using a resorbable Vicryl membrane, in a single-stage guided tissue regenerative technique; and was followed up after 5 years.

  4. National clinical guidelines for the extraction of first permanent molars in children.

    PubMed

    Cobourne, M T; Williams, A; Harrison, M

    2014-12-05

    This article summarises recently updated guidelines produced by the Clinical Governance Directorate of the British Orthodontic Society through the Clinical Standards Committee of the Faculty of Dental Surgery, Royal College of Surgeons of England (FDSRCS) on the extraction of first permanent molars in children. The first permanent molar is susceptible to chronological enamel defects, molar-incisor hypomineralisation and caries, which may necessitate enforced extraction in the developing dentition. In the right circumstances, the extraction of these teeth can be followed by successful eruption of the second permanent molar and ultimately, third molar eruption to complete the molar dentition. For this reason, elective extraction of first permanent molars with a questionable long-term prognosis should be considered when planning enforced extractions. However, a number of factors can influence the decision-making process, including the necessity for a general anaesthetic to allow extraction, potential cooperation with restorative or orthodontic treatment and likely future preventative practice within the family. Moreover, the presence of any underlying malocclusion also needs to be evaluated within the context of extraction planning. The current available evidence has been evaluated and awarded a grade based upon those recommended by the Scottish Intercollegiate Guidelines Network.

  5. High speed internal permanent magnet machine and method of manufacturing the same

    DOEpatents

    Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi; Lokhandwalla, Murtuza; Shah, Manoj Ramprasad; VanDam, Jeremy Daniel

    2011-09-13

    An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple permanent magnets for generating a magnetic field, which interacts with the stator magnetic field to produce torque. The permanent magnets are disposed between the stacks. The rotor assembly also includes multiple bottom wedges disposed on the bottom structures of the shaft and configured to hold the multiple stacks and the multiple permanent magnets.

  6. Preliminary surface analysis of etched, bleached, and normal bovine enamel

    SciTech Connect

    Ruse, N.D.; Smith, D.C.; Torneck, C.D.; Titley, K.C. )

    1990-09-01

    X-ray photoelectron spectroscopic (XPS) and secondary ion-mass spectroscopic (SIMS) analyses were performed on unground un-pumiced, unground pumiced, and ground labial enamel surfaces of young bovine incisors exposed to four different treatments: (1) immersion in 35% H2O2 for 60 min; (2) immersion in 37% H3PO4 for 60 s; (3) immersion in 35% H2O2 for 60 min, in distilled water for two min, and in 37% H3PO4 for 60 s; (4) immersion in 37% H3PO4 for 60 s, in distilled water for two min, and in 35% H2O2 for 60 min. Untreated unground un-pumiced, unground pumiced, and ground enamel surfaces, as well as synthetic hydroxyapatite surfaces, served as controls for intra-tooth evaluations of the effects of different treatments. The analyses indicated that exposure to 35% H2O2 alone, besides increasing the nitrogen content, produced no other significant change in the elemental composition of any of the enamel surfaces investigated. Exposure to 37% H3PO4, however, produced a marked decrease in calcium (Ca) and phosphorus (P) concentrations and an increase in carbon (C) and nitrogen (N) concentrations in unground un-pumiced specimens only, and a decrease in C concentration in ground specimens. These results suggest that the reported decrease in the adhesive bond strength of resin to 35% H2O2-treated enamel is not caused by a change in the elemental composition of treated enamel surfaces. They also suggest that an organic-rich layer, unaffected by acid-etching, may be present on the unground un-pumiced surface of young bovine incisors. This layer can be removed by thorough pumicing or by grinding. An awareness of its presence is important when young bovine teeth are used in a model system for evaluation of resin adhesiveness.

  7. Bovine respiratory disease model based on dual infections with infection with bovine viral diarrhea virus and bovine corona virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine respiratory disease complex (BRDC) is the leading cause of economic loss in the U.S. cattle industry. BRDC likely results from simultaneous or sequential infections with multiple pathogens including both viruses and bacteria. Bovine viral diarrhea virus (BVDV) and bovine corona virus (BoCV...

  8. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier.

  9. Transposition of teeth: A forensic perspective

    PubMed Central

    Nambiar, Supriya; Mogra, Subraya; Shetty, Surendra

    2014-01-01

    Dental identification plays a key role in mass casualties and is usually based on disturbances of tooth eruption, malocclusions and/or previous dental treatments, changes brought about by age, pathological conditions and developmental disturbances. Tooth transposition is a disturbance of tooth eruption and is defined as change in the position of two adjacent teeth within the same quadrant. This review aims to discuss the prevalence and the etiology of transposition through a literature survey and to discuss its importance and implications as pertaining to the field of forensics. In summary, transposition is a rare and severe positional anomaly that represents a challenge for a dentist. It requires a keen eye on the part of the forensic pathologist to identify the condition. PMID:25177135

  10. Infundibula of equine maxillary cheek teeth: Part 2: Morphological variations and pathological changes.

    PubMed

    Suske, A; Pöschke, A; Müller, P; Wöber, S; Staszyk, C

    2016-03-01

    Incomplete cemental filling of the infundibula of equine maxillary cheek teeth (CT) is a common feature. Depending on the extent of the defect, three stages of infundibular decay have been suggested. However, histomorphological criteria to identify non-pathological abnormalities and destructive changes have not been defined. Six hundred and eighty eight CT with no evidence of dental diseases and 55 diseased permanent, fully erupted maxillary CT were evaluated on a macroscopic level by assessing the occlusal surface and horizontal sections, including porphyrin assays to detect residual blood within the infundibular cementum. Selected specimens were investigated on a microscopic level using routine and immunohistological staining methods to identify possible routes for the spread of infectious agents from the infundibulum into the endodontic system. Infundibular cemental hypoplasia was defined as a non-pathological developmental abnormality and was detected in >50% of CT with no evidence of dental diseases and in >70% of diseased CT. The first molar (Triadan 09) showed the highest prevalence (75%) of infundibular cemental hypoplasia. The mesial infundibulum was more often affected than the distal infundibulum. Infundibular erosion was considered as the most appropriate term to describe destructive infundibular changes. Infundibular erosion was present in <6% of CT with no evidence of dental diseases, but was detected in >27% of diseased teeth, always accompanied by endodontic disease. This suggests that teeth affected by infundibular cemental hypoplasia are prone to destructive erosion, which possibly leads to endodontic disease. Morphological factors that supplement this ethological hypothesis were described. In 74% of infundibula residual blood was identified, although no vital blood vessels were detected. It is assumed that this content of blood remained in the ample infundibular cemental blood system after tooth eruption and creates a favorable environment for

  11. Modified anchor shaped post core design for primary anterior teeth.

    PubMed

    Rajesh, R; Baroudi, Kusai; Reddy, K Bala Kasi; Praveen, B H; Kumar, V Sumanth; Amit, S

    2014-01-01

    Restoring severely damaged primary anterior teeth is challenging to pedodontist. Many materials are tried as a post core but each one of them has its own drawbacks. This a case report describing a technique to restore severely damaged primary anterior teeth with a modified anchor shaped post. This technique is not only simple and inexpensive but also produces better retention.

  12. Modified Anchor Shaped Post Core Design for Primary Anterior Teeth

    PubMed Central

    Rajesh, R.; Baroudi, Kusai; Reddy, K. Bala Kasi; Praveen, B. H.; Kumar, V. Sumanth; Amit, S.

    2014-01-01

    Restoring severely damaged primary anterior teeth is challenging to pedodontist. Many materials are tried as a post core but each one of them has its own drawbacks. This a case report describing a technique to restore severely damaged primary anterior teeth with a modified anchor shaped post. This technique is not only simple and inexpensive but also produces better retention. PMID:25379294

  13. Endodontic and restorative management of incompletely fractured molar teeth.

    PubMed

    Gutmann, J L; Rakusin, H

    1994-11-01

    The treatment of fractured teeth poses significant problems for the practitioner. However, once the treatment planning decision has been made to attempt to retain the tooth, various practical regimens are available to effect this goal. This paper addresses the specific use of glass ionomer in the restorative management of incompletely, vertically fractured molar teeth integrated with specific root canal treatment techniques.

  14. Molar incisor hypomineralization (MIH): conservative treatment management to restore affected teeth.

    PubMed

    Fragelli, Camila Maria Bullio; Souza, Juliana Feltrin de; Jeremias, Fabiano; Cordeiro, Rita de Cássia Loiola; Santos-Pinto, Lourdes

    2015-01-01

    The purpose of this study was to evaluate the 12-month clinical performance of glass ionomer restorations in teeth with MIH. First permanent molars affected by MIH (48) were restored with glass ionomer cement (GIC) and evaluated at baseline, at 6 and at 12 months, by assessing tooth enamel breakdown, GIC breakdown and caries lesion associations. The data were analyzed using the chi-square test and actuarial survival analysis. The likelihood of a restored tooth remaining unchanged at the end of 12 months was 78%. No statistically significant difference was observed in the association between increased MIH severity and caries at baseline (p > 0.05) for a 6-month period, or between increased MIH severity and previous unsatisfactory treatment at baseline (p > 0.05) for both a 6- and 12-month period. A statistically significant difference was observed in the association between increased MIH severity and extension of the restoration, involving 2 or more surfaces (p < 0.05) at both periods, and between increased MIH severity and caries at baseline (p < 0.05) at a 12-month period. Because the likelihood of maintaining the tooth structures with GIC restorations is high, invasive treatment should be postponed until the child is sufficiently mature to cooperate with the treatment, mainly of teeth affected on just one face.

  15. [Clinical anatomy of the horse: teeth and dentition].

    PubMed

    Staszyk, C

    2015-01-01

    The routine inspection of the equine oral cavity allows a numerical assessment of the teeth and provides information about positional changes within the dentition. By use of appropriate dental equipment, the occlusal surfaces of all teeth can be inspected and diagnosed. However, neither the teeth nor their occlusal surfaces are constant structures. Instead, equine teeth and, in particular, their occlusal surfaces are subjected to continuous morphological and positional changes due to the effects of aging and the equine-specific high amount of occlusal wear. Therefore, it is mandatory to define anatomical criteria, which allow us to distinguish between anatomical variations and pathological conditions. Moreover, an unambiguous nomenclature with regard to the equine-specific dental anatomy is essential. This article provides a tutorial overview of the equine dental anatomy as well as recent findings in the field of equine dentistry. Special attention is paid to dynamic changes within both individual teeth and dentition.

  16. Improvement in properties of plastic teeth by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Sano, Yuko; Ishikawa, Shun-ichi; Seguchi, Tadao

    2011-11-01

    Improvement of the comfort and esthetics of artificial plastic teeth is desirable for the recently increasing numbers of elderly in society. Plastic teeth made of polycarbonate (PC) were modified by electron beam (EB) irradiation under specific conditions, and the change in the chemical properties of the PC was investigated. The water absorption, glucose attachment, level of bis-phenol-A (BPA) extraction, maltose adhesion, and mucin adhesion on the PC teeth were measured before and after EB irradiation. EB irradiation to a dose of 3.5 kGy at 150 °C in a nitrogen gas atmosphere reduced the water absorption by 20%, glucose absorption by 40%, maltose adhesion by 20%, and the amount of various amino acids, formed as the hydrolysis products of mucin, adhering on the PC teeth were reduced by 60-99%. The BPA content was lower than the detection limit for analysis of both the original and the EB irradiated PC teeth.

  17. Esthetic rehabilitation of discolored anterior teeth with porcelain veneers

    PubMed Central

    Kamble, Vaibhav D.; Parkhedkar, Rambhau D.

    2013-01-01

    The common man is bombarded by the media extolling the virtues of “the perfect smile.” In the 21st century of esthetic dentistry, fractured, malformed, malposed, and discolored teeth can be changed and restored to highly desirable form due to introduction of wide range of esthetic materials and techniques. Porcelain veneers is a conservative method of restoring the appearance of discolored, pitted teeth, and teeth with diastemas that provide extremely good esthetic results. A 21-year-old female patient with staining in anterior teeth had reported to the Department of Prosthodontics for esthetic rehabilitation. The patient was treated with porcelain veneers on maxillary anterior teeth. The patient was satisfied with the enhanced esthetic appearance. PMID:23853471

  18. Interim restorative approach for the management of congenitally missing permanent mandibular incisors: presentation of three cases.

    PubMed

    Prakash, Prashanth; Hallur, Jayadev M; Gowda, Rachana Narse

    2011-01-01

    Congenital missing of mandibular permanent incisors with retained primary incisors may jeopardize the esthetic appearance and psychological development of children, especially during the years of transition into adolescence. The retained primary teeth are necessary for the maintenance and normal development of alveolar bone, which in turn is essential for future definitive rehabilitation. In such situations, an interim restoration may be provided before any definitive treatment is given to comfort the young patient during this transition period. Interim restorations may include resin-modified additions to the existing teeth as well as more sophisticated restorations such as resin-retained bridge and removable partial dentures. However, this restoration differs for different clinical situations based on various factors such as age and patient compliance, and also consideration has to be given for the growth changes of the child. The aim of this present paper is to discuss the esthetic management of three cases with bilateral agenesis of permanent mandibular incisors and retained primary incisors with composite interim restoration.

  19. Interim Restorative Approach for the Management of Congenitally Missing Permanent Mandibular Incisors: Presentation of Three Cases

    PubMed Central

    Prakash, Prashanth; Hallur, Jayadev M.; Gowda, Rachana Narse

    2011-01-01

    Congenital missing of mandibular permanent incisors with retained primary incisors may jeopardize the esthetic appearance and psychological development of children, especially during the years of transition into adolescence. The retained primary teeth are necessary for the maintenance and normal development of alveolar bone, which in turn is essential for future definitive rehabilitation. In such situations, an interim restoration may be provided before any definitive treatment is given to comfort the young patient during this transition period. Interim restorations may include resin-modified additions to the existing teeth as well as more sophisticated restorations such as resin-retained bridge and removable partial dentures. However, this restoration differs for different clinical situations based on various factors such as age and patient compliance, and also consideration has to be given for the growth changes of the child. The aim of this present paper is to discuss the esthetic management of three cases with bilateral agenesis of permanent mandibular incisors and retained primary incisors with composite interim restoration. PMID:22567446

  20. CBCT evaluation of multiple idiopathic internal resorptions in permanent molars: case report

    PubMed Central

    2014-01-01

    Background Internal inflammatory root resorption is a rare condition in permanent teeth, which requires the presence of necrotic and infected pulp tissue within the coronal portion of the root canal system as well as inflamed pulp tissue apical to the resorptive defect. The aetiology of internal root resorption is not completely understandable, trauma and chronic pulpitis are considered the main risk factors. Case presentation We report a rare case of the multiple idiopathic resorption in the permanent maxillary and mandibular molars in a healthy 33-year-old female patient. In addition to clinical examination the patient was imaged using conventional radiography techniques and cone beam computed tomography (CBCT).The patient had recurrent throbbing pain in her # 46. The radiographic examination including “panoramic radiography and CBCT” revealed that radiographic evidence of internal resorption in #37 #36 #35 #34 #33 #47 #46 #45 #44 #43 #16 #15 #14 #13 and also including in unerupted #17, #26, #27, #28 teeth. The definitive diagnosis was made with the histopathological examination of the extracted tooth. Conclusions Internal root resorption is a rare clinical process that should be examined using different radiographic modalities. CBCT seems to be useful in evaluation of the lesions with superior diagnostic performance. PMID:24739085

  1. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District of... of the Commission shall have full charge and control of said offices, respectively....

  2. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District of... of the Commission shall have full charge and control of said offices, respectively....

  3. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District of... of the Commission shall have full charge and control of said offices, respectively....

  4. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District of... of the Commission shall have full charge and control of said offices, respectively....

  5. 22 CFR 401.3 - Permanent offices.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE General § 401.3 Permanent offices. The permanent offices of the Commission shall be at Washington, in the District of... of the Commission shall have full charge and control of said offices, respectively....

  6. First permanent molars with molar incisor hypomineralisation.

    PubMed

    Fitzpatrick, Laura; O'Connell, Anne

    2007-01-01

    Molar incisor hypomineralisation (MIH) is a common enamel defect presenting in the first permanent molars (FPM) and permanent incisors. This article presents the clinical findings and management considerations for the FPM with MIH to the general practitioner. The various treatment options are described with emphasis placed on early diagnosis as the most important prognostic factor.

  7. Finite element modeling of permanent magnet devices

    NASA Astrophysics Data System (ADS)

    Brauer, J. R.; Larkin, L. A.; Overbye, V. D.

    1984-03-01

    New techniques are presented for finite element modeling of permanent magnets in magnetic devices such as motors and generators. These techniques extend a previous sheet-current permanent magnet model that applies only for straight line B-H loops and rectangular-shaped magnets. Here Maxwell's equations are used to derive the model of a permanent magnet having a general curved B-H loop and any geometric shape. The model enables a nonlinear magnetic finite element program to use Newton-Raphson iteration to solve for saturable magnetic fields in a wide variety of devices containing permanent magnets and steels. The techniques are applied to a brushless dc motor with irregular-shaped permanent magnets. The calculated motor torque agrees well with measured torque.

  8. Permanent magnet multipole with adjustable strength

    DOEpatents

    Halbach, Klaus

    1985-01-01

    Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling therebetween. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

  9. Permanent-magnet multipole with adjustable strength

    DOEpatents

    Halbach, K.

    1982-09-20

    Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling there between. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

  10. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  11. Leadership in a (permanent) crisis.

    PubMed

    Heifetz, Ronald; Grashow, Alexander; Linsky, Marty

    2009-01-01

    The current economic crisis is not just another rough spell. Today's mix of urgency, high stakes, and uncertainty will continue even after the recession ends. The immediate crisis--which we will get through with policy makers' expert technical adjustments--sets the stage for a sustained, or even permanent, crisis, a relentless series of challenges no one has encountered before. Instead of hunkering down and relying on their familiar expertise to deal with the sustained crisis, people in positions of authority--whether they are CEOs or managers heading up a company initiative--must practice what the authors call adaptive leadership. They must, of course, tackle the underlying causes of the crisis, but they must also simultaneously make the changes that will allow their organizations to thrive in turbulent environments. Adaptive leadership is an improvisational and experimental art, requiring some new practices. Like Julie Gilbert, who overcame internal resistance to reorient Best Buy toward female purchasers, adaptive leaders get things done to meet today's challenges and then modify those things to thrive in tomorrow's world. They also embrace disequilibrium, using turbulence as an opportunity to build crucial new capacities, as Paul Levy did to rescue Beth Israel Deaconess Medical Center from a profound financial crisis. Finally, adaptive leaders, such as Egon Zehnder, the founder of an executive search firm, draw out the leadership skills that reside deep in the organization, recognizing the interdependence of all employees and mobilizing everyone to generate solutions.

  12. Sex discrimination potential of permanent maxillary molar cusp diameters.

    PubMed

    Macaluso, P J

    2010-12-01

    The purpose of the present investigation was to assess the potential usefulness of permanent maxillary molar cusp diameters for sex discrimination of poorly preserved skeletal remains. Cusp diameters were measured from standardized occlusal view photographs in a sample of black South Africans consisting of 130 males and 105 females. Results demonstrated that all cusp dimensions for both first and second maxillary molars exhibited significant sexual dimorphism (p < 0.001). Univariate and multivariate discriminant function equations permitted low to moderate classification accuracy in discriminating sex (58.3%-73.6%). The allocation accuracies for cusp diameter measurements were as high as, and even surpassed, those observed for conventional crown length and breadth dimensions of the same teeth. The most accurate result (73.6%, with a sex bias of only 0.5%) was obtained when all cusp diameters from both maxillary molars were used concurrently. However, only slightly less accurate results (~70.0%) were achieved when selected dimensions from only one of the molars, or even a single cusp, were utilized. Although not as reliable at predicting sex as other skeletal elements in black South Africans, the derived odontometric standards can be used with highly fragmentary skeletal material, as well as immature remains in which crown formation of the maxillary molars is complete.

  13. Material Properties of Inorganic Bovine Cancellous Bovine: Nukbone

    NASA Astrophysics Data System (ADS)

    Piña, Cristina; Palma, Benito; Munguía, Nadia

    2006-09-01

    In this work, inorganic cancellous bovine bone implants prepared in the Instituto de Investigaciones en Materiales — UNAM were characterized. Elementary chemical analysis was made, toxic elements concentration were measured and the content of organic matter also. These implants fulfill all the requirements of the ASTM standards, and therefore it is possible their use in medical applications.

  14. Development and evaluation of a standardized method and atlas for contouring primary and permanent dentition

    PubMed Central

    Fang, P; Batra, S; Hollander, A B; Lin, A; Hill-Kayser, C E; Levin, L M; Mupparapu, M

    2015-01-01

    Objectives: Radiation toxicity of the dentition may present significant treatment-related morbidity in the paediatric head and neck cancer population. However, clear dose–effect relationships remain undetermined and must be predicated upon accurate structure delineation and dosimetry at the individual tooth level. Radiation oncologists generally have limited familiarity or experience with relevant dental anatomy. Methods: We therefore developed a detailed CT atlas of permanent and primary dentition. After studying this atlas, five radiation oncology clinicians delineated all teeth for each of eight different cases (selected for breadth of dental maturity and anatomical variability). They were asked to record confidence in their contours on a per-tooth basis as well as the duration of time required per case. Contour accuracy and interclinician variability were assessed by Hausdorff distance and Dice similarity coefficient. All analyses were performed using R v. 3.1.1 and the RadOnc v. 1.0.9 package. Results: Participating clinicians delineated teeth with varying degrees of completeness and accuracy, stratified primarily by the age of the subject. On a per-tooth basis, delineation of permanent dentition was feasible for incisors, canines, premolars and first molars among all subjects, even at the youngest ages. However, delineation of second and third molars was less consistent, commensurate with approximate timing of tooth development. Within each tooth contour, uncertainty was the greatest at the level of the dental roots. Conclusions: Delineation of individual teeth is feasible and serves as a necessary precursor for dental dose assessment and avoidance. Among the paediatric radiation oncology community in particular, this atlas may serve as a useful tool and reference. PMID:25812046

  15. The ins and outs of the evolutionary origin of teeth.

    PubMed

    Donoghue, Philip C J; Rücklin, Martin

    2016-01-01

    The role of teeth and jaws, as innovations that underpinned the evolutionary success of living jawed vertebrates, is well understood, but their evolutionary origins are less clear. The origin of teeth, in particular, is mired in controversy with competing hypotheses advocating their origin in external dermal denticles ("outside-in") versus a de novo independent origin ("inside-out"). No evidence has ever been presented demonstrating materially the traditional "outside-in" theory of teeth evolving from dermal denticles, besides circumstantial evidence of a commonality of structure and organogenesis, and phylogenetic evidence that dermal denticles appear earlier in vertebrate phylogeny that do teeth. Meanwhile, evidence has mounted in support of "inside-out" theory, through developmental studies that have indicated that endoderm is required for tooth development, and fossil studies that have shown that tooth-like structures evolved before dermal denticles (conodont dental elements), that tooth replacement evolving before teeth (thelodont pharyngeal denticles), and that teeth evolved many times independently through co-option of such structures. However, the foundations of "inside-out" theory have been undermined fatally by critical reanalysis of the evidence on which it was based. Specifically, it has been shown that teeth develop from dermal, endodermal or mixed epithelia and, therefore, developmental distinctions between teeth and dermal denticles are diminished. Furthermore the odontode-like structure of conodont elements has been shown to have evolved independently of dermal and internal odontodes. The tooth-like replacement encountered in thelodont pharyngeal odontodes has been shown to have evolved independently of teeth and tooth replacement and teeth have been shown to have evolved late within the gnathostome stem lineage indicating that it is probable, if not definitive, that teeth evolved just once in gnathostome evolution. Thus, the "inside-out" hypothesis

  16. 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.

  17. The Use of Glass-fibers Ribbon and Composite for Prosthetic Restoration of Missing Primary Teeth-Laboratory and Clinical Research.

    PubMed

    Zilberman, Uri; Lasilla, Lippo

    2014-01-01

    Very few modalities can be used for restoring missing primary anterior teeth, although the impact of missing anterior teeth during early childhood can be harmful. In the permanent dentition the use of glass-fibers ribbon and composite materials are frequently used for restoring missing teeth with no or minimal preparation. The purpose of this study was to examine the possibility to use the glass-fibers ribbon (ever-Stick from GC Corporation, Japan) together with esthetic composite materials (G-aenial A1 from GC Corporation, Japan) for restoring anterior primary teeth and to determine the best methodology and bonding system to be used. The effect of etching time was analyzed using 20-80 sec on primary buccal enamel with SEM and the results showed that at least 60 second is necessary in order to remove the prismless layer and to affect the prismatic layer similar (as observed by SEM) to the 20 sec etching time on permanent enamel. Three bonding systems (SE Bond by Kurary, Japan, Scotchbond Universal by 3M/ESPE, Germany and G-aenial bond by GC Company, Japan) were compared for bonding the glass-fibers ribbon to the primary enamel and microtensile strength analyses were performed. Mean tensile strength ranged from 10.9 to 13 MPa with no statistically significant differences between all three systems. Based on the laboratory results it can be concluded that the glass-fibers ribbon together with the composite material can be used clinically to restore missing primary teeth for esthetic and functional reasons. Two clinical cases are presented that show favorable results.

  18. Efficacy of revascularization to induce apexification/apexogensis in infected, nonvital, immature teeth: a pilot clinical study.

    PubMed

    Shah, Naseem; Logani, Ajay; Bhaskar, Uday; Aggarwal, Vivek

    2008-08-01

    Endodontic treatment options for immature, nonvital teeth conventionally include surgical endodontics, apexification with calcium hydroxide, or single visit mineral trioxide aggregate plug. A new treatment option of revascularization has recently been introduced. It involves disinfecting the root canal system, providing a matrix of blood clot into which cells could grow, and sealing of the coronal access. The present pilot clinical study was undertaken to evaluate the efficacy of revascularization in 14 cases of infected, immature teeth. Endodontic treatment was initiated, and after infection control, revascularization was performed. The access cavity was sealed with glass ionomer cement. The cases were followed up at regular intervals of 3 months; the range in follow-up was 0.5-3.5 years. The outcomes were as follows. Radiographic resolution of periradicular radiolucencies was judged to be good to excellent in 93% (13 of 14) of the cases. In the majority of cases, a narrowing of the wide apical opening was evident. In 3 cases, thickening of apical dentinal walls and increased root length were observed. The striking finding was complete resolution of clinical signs and symptoms and appreciable healing of periapical lesions in 78% (11 of 14) of cases. Thickening of lateral dentinal walls was evident in 57% (8/14) of cases, and increased root length was observed in 71% (10/14) of cases. None of the cases presented with pain, reinfection, or radiographic enlargement of preexisting apical pathology. This pilot study documented a favorable outcome of revascularization procedures conducted in immature nonvital, infected permanent teeth.

  19. A curriculum vitae of teeth: evolution, generation, regeneration.

    PubMed

    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.

  20. Sterilization of extracted human teeth: A comparative analysis

    PubMed Central

    Sandhu, Simarpreet V.; Tiwari, Rajiv; Bhullar, RamanPreet K.; Bansal, Himanta; Bhandari, Rajat; Kakkar, Tushaar; Bhusri, Ridhima

    2012-01-01

    Background Extracted human teeth are regularly used for practice and educational purposes in dental institutions at undergraduate and postgraduate levels. Different materials and methods are used for sterilizing extracted teeth to avoid infection from them. Aims The present study was done to determine the efficacy of some frequently used methods for disinfection/sterilization of extracted human teeth. Materials and methods A total of 120 intact, non-carious teeth extracted due to periodontal or orthodontic purpose were divided randomly into 8 groups consisting of 15 teeth in each group. Agents used for sterilization included 10% formalin, 0.1% thymol in distilled water, 5.25% sodium hypochlorite, 2% glutaraldehyde, 3% hydrogen peroxide, boiled in water (100 °C), autoclave (121 °C, 15 lbs psi), normal saline. Samples were collected with the help of inoculating loop and then streaked over the surface of Mc-Conkey agar medium and Blood agar medium. The media were then incubated at 37 °C for 24 h. No visible growth in the culture medium was considered as the method of effective sterilization. Results 10% formalin, autoclaving, 5.25% sodium hypochlorite could be efficiently used for sterilization and disinfection of extracted human teeth. Conclusion Extracted teeth should be handled with extreme care as these are potential source of infection and need to be disinfected before they are used in the laboratories. PMID:25737861

  1. Application of biomimetic mineralization: a prophylactic therapy for cracked teeth?

    PubMed

    Lin, Yixin; Zheng, Ren; He, Hao; Du, Huali; Lin, Yinghe

    2009-10-01

    Cracked teeth are usually found and easily ignored in clinic. If not found in time, they can lead to pulpitis and teeth fractures, which even can make the cracked teeth pulled out. The current treatments for cracked teeth include occlusal adjustments or preventive fillings, and the root canal therapy or complete crown restoration, which is decided according to the depth of cracks. However, the successful rate of preserving cracked teeth is less than 50% through occlusal adjustments and preventive fillings. Although the successful rate can reach 80% through the root canal therapy and complete crowns, the pulp and normal tooth can not be reserved. So the harms are very serious that prevention of its further development is extremely important. Nanobacteria have a very unique role in biological mineralization, which can produce crystalline apatites in the conditions of physiological calcium and phosphorus concentrations. Therefore, a hypothesis is put forward that application of nanobacteria may mineralize the cracks of teeth. Then the development of cracked teeth would be completely stopped.

  2. Indirect pulp therapy: an alternative to pulpotomy in primary teeth.

    PubMed

    Seale, N Sue

    2010-11-01

    Preservation of the primary teeth until their normal exfoliation is essential for normal oral function and facial growth of the child. To that end, treatment of primary teeth with large carious lesions approximating the pulp should be aimed at preserving the tooth. Currently, the pulpotomy is the most frequently used pulp treatment for cariously involved primary teeth. The purpose of this manuscript is to describe the use of an alternative to the pulpotomy, indirect pulp therapy (IPT), for the treatment of vital, primary teeth with carious involvement approaching the pulp. Accurate diagnosis of the vitality status of the pulp is critical to the success of IPT and involves careful radiographic and clinical assessment of the teeth to be sure they are healthy or at worst, reversibly inflamed. The indications for IPT are the same as for pulpotomy. The technique involves one appointment, requires that some carious dentin be left to avoid pulp exposure and requires the placement of a biologically sealing base and sealing final restoration. Teeth treated with IPT have success rates at least as good as those treated with pulpotomies, and IPT offers an acceptable alternative to pulpotomy as a treatment for vital, asymptomatic, cariously involved primary teeth.

  3. Permanency and the Foster Care System.

    PubMed

    Lockwood, Katie K; Friedman, Susan; Christian, Cindy W

    2015-10-01

    Each year over 20,000 youth age out of the child welfare system without reaching a permanent placement in a family. Certain children, such as those spending extended time in foster care, with a diagnosed disability, or adolescents, are at the highest risk for aging out. As young adults, this population is at and increased risk of incarceration; food, housing, and income insecurity; unemployment; educational deficits; receipt of public assistance; and mental health disorders. We reviewed the literature on foster care legislation, permanency, outcomes, and interventions. The outcomes of children who age out of the child welfare system are poor. Interventions to increase permanency include training programs for youth and foster parents, age extension for foster care and insurance coverage, an adoption tax credit, and specialized services and programs that support youth preparing for their transition to adulthood. Future ideas include expanding mentoring, educational support, mental health services, and post-permanency services to foster stability in foster care placements and encourage permanency planning. Children in the child welfare system are at a high risk for physical, mental, and emotional health problems that can lead to placement instability and create barriers to achieving permanency. Failure to reach the permanency of a family leads to poor outcomes, which have negative effects on the individual and society. Supporting youth in foster care throughout transitions may mediate the negative outcomes that have historically followed placement in out-of-home care.

  4. Development of teeth and jaws in the earliest jawed vertebrates.

    PubMed

    Rücklin, Martin; Donoghue, Philip C J; Johanson, Zerina; Trinajstic, Kate; Marone, Federica; Stampanoni, Marco

    2012-11-29

    Teeth and jaws constitute a model of the evolutionary developmental biology concept of modularity and they have been considered the key innovations underpinning a classic example of adaptive radiation. However, their evolutionary origins are much debated. Placoderms comprise an extinct sister clade or grade to the clade containing chondrichthyans and osteichthyans, and although they clearly possess jaws, previous studies have suggested that they lack teeth, that they possess convergently evolved tooth-like structures or that they possess true teeth. Here we use synchrotron radiation X-ray tomographic microscopy (SRXTM) of a developmental series of Compagopiscis croucheri (Arthrodira) to show that placoderm jaws are composed of distinct cartilages and gnathal ossifications in both jaws, and a dermal element in the lower jaw. The gnathal ossification is a composite of distinct teeth that developed in succession, polarized along three distinct vectors, comparable to tooth families. The teeth are composed of dentine and bone, and show a distinct pulp cavity that is infilled centripetally as development proceeds. This pattern is repeated in other placoderms, but differs from the structure and development of tooth-like structures in the postbranchial lamina and dermal skeleton of Compagopiscis and other placoderms. We interpret this evidence to indicate that Compagopiscis and other arthrodires possessed teeth, but that tooth and jaw development was not developmentally or structurally integrated in placoderms. Teeth did not evolve convergently among the extant and extinct classes of early jawed vertebrates but, rather, successional teeth evolved within the gnathostome stem-lineage soon after the origin of jaws. The chimaeric developmental origin of this model of modularity reflects the distinct evolutionary origins of teeth and of component elements of the jaws.

  5. First fossil evidence for the advance of replacement teeth coupled with life history evolution along an anagenetic mammalian lineage.

    PubMed

    Jordana, Xavier; Marín-Moratalla, Nekane; Moncunill-Solé, Blanca; Bover, Pere; Alcover, Josep Antoni; Köhler, Meike

    2013-01-01

    In mammals that grow up more slowly and live longer, replacement teeth tend to appear earlier in sequence than in fast growing mammals. This trend, known as 'Schultz's Rule', is a useful tool for inferring life histories of fossil taxa. Deviations from this rule, however, suggest that in addition to the pace of life history, ecological factors may also drive dental ontogeny. Myotragus balearicus is an extinct insular caprine that has been proved to be an excellent test case to correlate morphological traits with life history. Here we show that Myotragus balearicus exhibits a slow signature of dental eruption sequence that is in agreement with the exceptionally slow life history of this species, thus conforming to 'Schultz's Rule'. However, our results also show an acceleration of the absolute pace of development of the permanent incisors in relation to that of the posterior teeth. The rodent-like incisors of Myotragus balearicus erupted early not only in relative but also in absolute terms (chronological age), suggesting that feeding characteristics also plays an important role in dental ontogeny. This is in agreement with ecological hypotheses based on primates. Our study documents a decoupling of the pace of development of teeth in mammals that is triggered by different selection pressures on dental ontogeny. Moreover, we show that Myotragus kopperi from the early Pleistocene (a direct ancestor of the late Pleistocene-Holocene M. balearicus) follows the pattern of first incisor replacement known in living bovids. Hence, the advance in the eruption sequence of the first incisors occurs along the Myotragus evolutionary lineage over a period of about 2.5 Myr. To our knowledge, this is the first fossil evidence of an advance of the emergence of the permanent first incisor along an anagenetic mammalian lineage.

  6. First Fossil Evidence for the Advance of Replacement Teeth Coupled with Life History Evolution along an Anagenetic Mammalian Lineage

    PubMed Central

    Jordana, Xavier; Marín-Moratalla, Nekane; Moncunill-Solé, Blanca; Bover, Pere; Alcover, Josep Antoni; Köhler, Meike

    2013-01-01

    In mammals that grow up more slowly and live longer, replacement teeth tend to appear earlier in sequence than in fast growing mammals. This trend, known as ‘Schultz's Rule’, is a useful tool for inferring life histories of fossil taxa. Deviations from this rule, however, suggest that in addition to the pace of life history, ecological factors may also drive dental ontogeny. Myotragus balearicus is an extinct insular caprine that has been proved to be an excellent test case to correlate morphological traits with life history. Here we show that Myotragus balearicus exhibits a slow signature of dental eruption sequence that is in agreement with the exceptionally slow life history of this species, thus conforming to ‘Schultz's Rule’. However, our results also show an acceleration of the absolute pace of development of the permanent incisors in relation to that of the posterior teeth. The rodent-like incisors of Myotragus balearicus erupted early not only in relative but also in absolute terms (chronological age), suggesting that feeding characteristics also plays an important role in dental ontogeny. This is in agreement with ecological hypotheses based on primates. Our study documents a decoupling of the pace of development of teeth in mammals that is triggered by different selection pressures on dental ontogeny. Moreover, we show that Myotragus kopperi from the early Pleistocene (a direct ancestor of the late Pleistocene-Holocene M. balearicus) follows the pattern of first incisor replacement known in living bovids. Hence, the advance in the eruption sequence of the first incisors occurs along the Myotragus evolutionary lineage over a period of about 2.5 Myr. To our knowledge, this is the first fossil evidence of an advance of the emergence of the permanent first incisor along an anagenetic mammalian lineage. PMID:23936247

  7. Minimally invasive treatment of dental caries in primary teeth using an Er:YAG Laser

    PubMed Central

    Rashkova, Maya; Rocca, Jean-Paul

    2014-01-01

    Introduction: Maintaining deciduous teeth as long as possible represents a goal in pediatric dentistry and avoids a plethora of health problems. Er:YAG carious decay treatment may help for prevention as well as during the curative processes. Materials and Methods: An Er:YAG laser was used to ablate 30 carious lesions on primary teeth. Diagnosis being conventionally dressed, treatment was conducted in respect of the following parameters: Er:YAG laser (Lite Touch, Syneron): output power from 300 mJ (enamel) to 200 mJ (dentine), frequency 20 Hz, sapphire tip (diameter 1.3 mm), air water spray ratio 8 (39 ml/min), pulse duration 50 µsec., theoretical fluence ranging from 15.08 J/cm2 for dentin to 22.61 J/cm2 for enamel. Then cavity depth was controlled (observation + probe). Glass-ionomer cement (GC Fuji Triage capsule) or flowable composite resin or compomer were used to fill the cavities. Children's acceptance to Er-YAG laser treatment was evaluated. According to predefined criteria, each case was followed up for one month after treatment and then with further monthly follow-ups for one year. Results: Clinical cases illustrate the validity of this clinical approach. The benefit of laser dental treatment has been shown to be the greatest in children. However, the lack of studies evaluating laser ablation capability in primary teeth restrains the adoption of this technology. The interaction between the Er:YAG laser and primary enamel and dentin depends on the composition of the tissues - a higher presence of water and lower presence of minerals- comparative to the permanent enamel and dentin. Thus, photoablation of primary enamel and dentin requires lower energy. This study shows that the laser parameters used (300 mJ/20 Hz for enamel and 200 mJ/20 Hz for dentin) are efficient enough for the ablation of tissues of deciduous teeth and moreover demonstrates to be well accepted by young patients. PMID:25705080

  8. Permanent Magnetic Bearing for Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    Morales, Winfredo; Fusaro, Robert; Kascak, Albert

    2008-01-01

    A permanent, totally passive magnetic bearing rig was designed, constructed, and tested. The suspension of the rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. The rig was successfully operated to speeds of 5500 rpm using an air impeller. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated.

  9. Permanent multipole magnets with adjustable strength

    SciTech Connect

    Halbach, K.

    1983-03-01

    Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrupole will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented.

  10. Macroscopic simulation of isotropic permanent magnets

    NASA Astrophysics Data System (ADS)

    Bruckner, Florian; Abert, Claas; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

    2016-03-01

    Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the hysteresis of the magnetic material. Strayfield measurements of an isotropic permanent magnet and simulation results are in good agreement and highlight the importance of a proper description of the isotropic material.

  11. Prospects for nanoparticle-based permanent magnets

    SciTech Connect

    Balamurugan, B; Sellmyer, DJ; Hadjipanayis, GC; Skomski, R

    2012-09-01

    Magnetic nanoparticles smaller than similar to 15 nm in diameter and with high magnetocrystalline anisotropies K-1 >= 1 MJ m(-3) can be used as building blocks for next-generation permanent magnets. Advances in processing steps are discussed, such as self-assembly, alignment of the easy axes and appropriate nanostructuring that will enable the fabrication of densely packed nanopartide assemblies with improved permanent-magnet properties. This study also proposes an idealized nanocomposite structure for nanoparticle-based future permanent magnets with enhanced energy products. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. Current aspects of restoring traumatically fractured teeth.

    PubMed

    Krastl, Gabriel; Filippi, Andreas; Zitzmann, Nicola U; Walter, Clemens; Weiger, Roland

    2011-01-01

    Endodontic and restorative considerations are of primary significance in the treatment of tooth fractures. Since exposed dentinal tubules permit invasion of bacteria into the endodontic system, a protective dressing must be applied as part of the emergency treatment. Provided the dentin wound has been sealed, restorative treatment can also be carried out at a later stage. The fractured tooth fragment can be reattached using adhesive protocols in order to restore function and esthetic appearance. If reattachment is difficult or impossible, eg, in cases of multiple or missing fragments, current composite materials enable excellent esthetic results. Minimally-invasive direct composite restorations are preferred over the more invasive indirect restorations, at least in immature teeth with an extensive coronal pulp dimension. Restorative treatment of crown-root fractures is frequently demanding due to inaccessible subgingival fracture margins. Extrusion of the remaining root is an alternative method to surgical crown lengthening for re-establishing the biological width. This can be carried out either orthodontically (forced eruption), or surgically (intra-alveolar transplantation). Although the treatment of crown-root fractures is one of the most technically sensitive procedures in dental traumatology and is frequently considered as a long-term temporary restoration, tooth conservation up to the age at which implants can be placed may be regarded as a success.

  13. The determination of lead in human teeth

    NASA Astrophysics Data System (ADS)

    Fremlin, J. H.; Edmonds, M. I.

    1980-06-01

    The effects of lead poisoning may be much more extensive than had been realised until recently. Industrial workers and the inhabitants of big cities are continuously absorbing small quantities and it is important to be able to detect excessive amounts over long periods. This can be done by examining teeth which have been extracted for other reasons. Tooth sections have been bombarded with 3He ions from the Birmingham 152 cm cyclotron. Several alpha-emitting isotopes of polonium are produced from any lead present. After bombardment the sections are held against an alpha-sensitive plastic track detector for a few days. Examination of the plastic then shows a distribution of tracks proportional to the distribution of lead in the tooth. Standards irradiated at the same time enable us to determine the absolute concentration. It is found that the concentration in the absorbed enamel records the lead absorbed during the time of the formation of the tooth while that in pulpal dentine shows the integrated take-up during the life of the tooth.

  14. Endodontic therapy of traumatised teeth in children.

    PubMed

    Winter, G B

    1977-09-01

    One of the most difficult problems met with in endodontic therapy for children is the traumatized anterior tooth whose root is still incomplete. In cases where the pulp is vital, treatment by pulp capping or pulpotomy is directed to preserving the vitality of the radicular pulp to ensure completion of root formation. Calcium hydroxide remains the material of choice in both forms of treatment. Once root formation is complete, removal of the pulp residue and filling of the root canal may be performed as a preliminary to restoration by means of a post retained crown. Where the pulp is non vital, attempts to fill the funnel shaped apical part of the canal, whether from a coronal approach or by open operation for retrograde filling, have proved unsatisfactory. Many workers have shown however that a number of root filling materials and root dressings are capable of inducing either continued root growth or a closure of the apical region by a calcific scar. A detailed survey of 34 teeth treated by this method has been made and the important principles which appear to influence the success of the technique are enumerated.

  15. Frequency of supernumerary teeth in Mexican population.

    PubMed

    Salcido-García, Juan Francisco; Ledesma-Montes, Constantino; Hernández-Flores, Florentino; Pérez, Diego; Garcés-Ortíz, Maricela

    2004-01-01

    Supernumerary teeth (ST) are a not uncommon developmental anomaly which appears in 0.3 to 3.8 percent of the population. We studied the corresponding radiographs from 2241 patients, both sexes who seeked dental attention at the Outpatient Clinic of the División de Estudios de Posgrado e Investigación, Facultad de Odontología, UNAM in Mexico City. Of them, we found 72 patients (3.2%) with 102 ST. Of the 72 patients, 39 were males (54.2%) and 33 females (45.8%). Mesiodens was the most common ST (48.6%), followed by supernumerary premolars (26.4%), supernumerary laterals (11.1%) and fourth molars (9.7%). This series includes cases with one, two and three ST and one case comprising 10 ST. Our results suggest that frequency of ST in the population studied differs in some aspects with previously reported series and that frequency of ST shows different rates depending the population studied. As our results demonstrate, it is encouraged the need to have panoramic radiographs of all patients attended in dental offices, clinics and schools of Dentistry in order to detect and diagnose undiscovered pathologies.

  16. Comparison of Periodontal Ligament Stem Cells Isolated from the Periodontium of Healthy Teeth and Periodontitis-Affected Teeth

    PubMed Central

    Soheilifar, Sara; Amiri, Iraj; Bidgoli, Mohsen; Hedayatipanah, Morad

    2016-01-01

    Objectives: Stem cell (SC) therapy is a promising technique for tissue regeneration. This study aimed to compare the viability and proliferation ability of periodontal ligament stem cells (PDLSCs) isolated from the periodontium of healthy and periodontitis-affected teeth to obtain an autologous, easily accessible source of SCs for tissue regeneration in periodontitis patients. Materials and Methods: The PDLSCs were isolated from the roots of clinically healthy premolars extracted for orthodontic purposes and periodontally involved teeth with hopeless prognosis (with and without phase I periodontal treatment). Cells were cultured and viability and proliferation ability of third passage cells in each group were evaluated using the methyl thiazol tetrazolium assay. The results were statistically analyzed using t-test. Results: No SCs could be obtained from periodontitis-affected teeth without phase I periodontal treatment. The viability of cells was 0.86±0.13 OD/540 in healthy group and 0.4±0.25 OD/540 in periodontitis-affected group (P=0.035). The proliferation ability (population doubling time) of cells obtained from healthy teeth was 4.22±1.23 hours. This value was 2.3±0.35 hours for those obtained from periodontitis-affected teeth (P=0.02). Conclusions: Viability and proliferation ability of cells isolated from the periodontium of healthy teeth were significantly greater than those of cells isolated from the periodontitis-affected teeth. PMID:28127319

  17. 30 CFR 817.132 - Cessation of operations: Permanent.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS PERMANENT PROGRAM PERFORMANCE STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.132 Cessation of operations: Permanent. (a) The person who conducts underground mining... equipment, structures, or other facilities not required for continued underground mining activities...

  18. 30 CFR 817.132 - Cessation of operations: Permanent.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS PERMANENT PROGRAM PERFORMANCE STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.132 Cessation of operations: Permanent. (a) The person who conducts underground mining... equipment, structures, or other facilities not required for continued underground mining activities...

  19. Gemination and Twinning in Permanent Dentition.

    DTIC Science & Technology

    1981-09-11

    tooth, 15 linking tooth,16 synodonia17 and schizodontla,11 mirror image double tooth,18 fused teeth, 19 and geminated composite odontoma . 20...normal fashion, whereas, in an odontoma ,ameloblasts and odontoblasts lay down enamel and dentin in small rudimentary tooth-like structures during

  20. 78 FR 72979 - Bovine Spongiform Encephalopathy; Importation of Bovines and Bovine Products

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-04

    ... the United States, while allowing the importation of additional animals and animal products into this... continue to guard against the introduction of bovine spongiform encephalopathy (BSE) into the United States... commitment of the United States to base its BSE regulations on internationally accepted scientific...

  1. Size and placement of developing anterior teeth in immature Neanderthal mandibles from Dederiyeh Cave, Syria: implications for emergence of the modern human chin.

    PubMed

    Fukase, Hitoshi; Kondo, Osamu; Ishida, Hajime

    2015-03-01

    Evolutionary and functional significance of the human chin has long been explored from various perspectives including masticatory biomechanics, speech, and anterior tooth size. Recent ontogenetic studies have indicated that the spatial position of internally forming anterior teeth partially constrains adult mandibular symphyseal morphology. The present study therefore preliminarily examined the size and placement of developing anterior teeth in immature Neanderthal mandibles of Dederiyeh 1 and 2, compared with similarly-aged modern humans (N = 16) and chimpanzees (N = 7) whose incisors are comparatively small and large among extant hominids, respectively. The Dederiyeh 1 mandible is described as slightly presenting a mental trigone and attendant mental fossa, whereas Dederiyeh 2 completely lacks such chin-associated configurations. Results showed that, despite symphyseal size being within the modern human range, both Dederiyeh mandibles accommodated overall larger anterior dentition and displayed a remarkably wide bicanine space compared to those of modern humans. Dederiyeh 2 had comparatively thicker deciduous incisor roots and more enlarged permanent incisor crypts than Dederiyeh 1, but both Dederiyeh individuals exhibited a total dental size mostly intermediate between modern humans and chimpanzees. These findings potentially imply that the large deciduous/permanent incisors collectively distended the labial alveolar bone, obscuring an incipient mental trigone. It is therefore hypothesized that the appearance of chin-associated features, particularly of the mental trigone and fossa, can be accounted for partly by developmental relationships between the sizes of the available mandibular space and anterior teeth. This hypothesis must be, however, further addressed with more referential samples in future studies.

  2. Design and analysis of new fault-tolerant permanent magnet motors for four-wheel-driving electric vehicles

    NASA Astrophysics Data System (ADS)

    Liu, Guohai; Gong, Wensheng; Chen, Qian; Jian, Linni; Shen, Yue; Zhao, Wenxiang

    2012-04-01

    In this paper, a novel in-wheel permanent-magnet (PM) motor for four-wheel-driving electrical vehicles is proposed. It adopts an outer-rotor topology, which can help generate a large drive torque, in order to achieve prominent dynamic performance of the vehicle. Moreover, by adopting single-layer concentrated-windings, fault-tolerant teeth, and the optimal combination of slot and pole numbers, the proposed motor inherently offers negligible electromagnetic coupling between different phase windings, hence, it possesses a fault-tolerant characteristic. Meanwhile, the phase back electromotive force waveforms can be designed to be sinusoidal by employing PMs with a trapezoidal shape, eccentric armature teeth, and unequal tooth widths. The electromagnetic performance is comprehensively investigated and the optimal design is conducted by using the finite-element method.

  3. 78 FR 14122 - Revocation of Permanent Variances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-04

    ... Occupational Safety and Health Administration Revocation of Permanent Variances AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of revocation. SUMMARY: With this notice, OSHA is... into consideration these newly corrected cross references. DATES: The effective date of the...

  4. Nonuniform radiation damage in permanent magnet quadrupoles

    SciTech Connect

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

    2014-08-15

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  5. Characterizing hydrologic permanence in headwater streams

    EPA Science Inventory

    The presentation will be an overview of research to inform jurisdictional determinations for the Clean Water Act, in particular research that hydrographic comparisons of the extent and hydrologic permanence of headwater streams, indicator development, and an evaluation of a rapid...

  6. Micromachined permanent magnets and their MEMS applications

    NASA Astrophysics Data System (ADS)

    Cho, Hyoung Jin

    2002-01-01

    In this research, new micromachined permanent magnets have been proposed, developed and characterized for MEMS applications. In realizing micromachined permanent magnets, a new electroplating technique using external magnetic field and a bumper filling technique using a photolithographically defined mold with resin bonded magnetic particles have been developed. The newly developed micromachining techniques allow thick film-type permanent magnet components to be integrated to magnetic MEMS devices with dimensional control and alignment. Permanent magnet arrays with the dimensions ranging from 30 mum to 200 mum have been developed with an energy density up to 2.7 kJ/m3 in precisely defined forms in the micro scale. For the applications of the permanent magnets developed in this work, three novel magnetic MEMS devices such as a bi-directional magnetic actuator, a magnetically driven optical scanner, and a magnetic cell separator have been successfully realized. After design and modeling, each device has been fabricated and fully characterized. The bi-directional actuator with the electroplated permanent magnet array has achieved bi-directional motion clearly and shown good agreement with the analytical and simulated models. The optical scanner has shown linear bi-directional response under static actuation and stable bi-directional scanning performance under dynamic actuation. As a potential BioMEMS application of the developed permanent magnet, the prototype magnetic cell separator using the electroplated permanent magnet strip array has been proposed and demonstrated for magnetic bead patterning. In conclusion, new thick film-type, electroplated CoNiMnP and epoxy resin bonded Sr-ferrite permanent magnets have been developed and characterized, and then, three new magnetic MEMS devices using the permanent magnets such as a bi-directional magnetic actuator, an optical scanner and a magnetic cell separator have been realized in this research. The new micromachined

  7. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, Roman O.

    1997-01-01

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

  8. Permanent education in health: a review

    PubMed Central

    Miccas, Fernanda Luppino; Batista, Sylvia Helena Souza da Silva

    2014-01-01

    OBJECTIVE To undertake a meta-synthesis of the literature on the main concepts and practices related to permanent education in health. METHODS A bibliographical search was conducted for original articles in the PubMed, Web of Science, LILACS, IBECS and SciELO databases, using the following search terms: “public health professional education”, “permanent education”, “continuing education”, “permanent education health”. Of the 590 articles identified, after applying inclusion and exclusion criteria, 48 were selected for further analysis, grouped according to the criteria of key elements, and then underwent meta-synthesis. RESULTS The 48 original publications were classified according to four thematic units of key elements: 1) concepts, 2) strategies and difficulties, 3) public policies and 4) educational institutions. Three main conceptions of permanent education in health were found: problem-focused and team work, directly related to continuing education and education that takes place throughout life. The main strategies for executing permanent education in health are discussion, maintaining an open space for permanent education, and permanent education clusters. The most limiting factor is mainly related to directly or indirect management. Another highlight is the requirement for implementation and maintenance of public policies, and the availability of financial and human resources. The educational institutions need to combine education and service aiming to form critical-reflexive graduates. CONCLUSIONS The coordination between health and education is based as much on the actions of health services as on management and educational institutions. Thus, it becomes a challenge to implement the teaching-learning processes that are supported by critical-reflexive actions. It is necessary to carry out proposals for permanent education in health involving the participation of health professionals, teachers and educational institutions. PMID:24789649

  9. Permanent magnet edge-field quadrupole

    DOEpatents

    Tatchyn, R.O.

    1997-01-21

    Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

  10. Restoration of primary anterior teeth: review of the literature.

    PubMed

    Lee, Jacob K

    2002-01-01

    This paper reviews the published data on restorations of primary anterior teeth. The discussion includes Class III restorations, Class V restorations, various forms of full coronal restorations, atraumatic restorative technique (ART) and recommendations for future research.

  11. 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

  12. [Teeth decoration back after a long and forgotten history].

    PubMed

    Dijs, F

    2004-09-01

    After the last ice-age modern man started to remove, file, dye and inlay teeth. The teeth had such a central role in the imagination that the habit of more or less ritual decoration by incurable manipulation of the teeth spread all over the world. The most skillful and artistic work was done by craftsmen of the Maya. Between 1500 and 1900 modern researchers classified the habits as primitive and barbarian but during the twentieth century some of them took the question seriously. In the last decennium tooth jewelery is sold more and more often. In two articles the history of teeth decoration is outlined. In this article the significance of the manipulations is emphasized. The second will focus on the changing appreciation of the phenomenon.

  13. Chediak-Higashi syndrome and premature exfoliation of primary teeth.

    PubMed

    Rezende, Karla Mayra; Canela, Alfredo Hiram Carrillo; Ortega, Adriana Oliveira Lira; Tintel, Claudia; Bönecker, Marcelo

    2013-01-01

    The Chediak-Higashi syndrome (CHS) is a rare hereditary fatal disease, if not treated. These changes are associated with various diseases and syndromes that mainly cause periodontal disease and thus the premature loss of teeth. This paper describes the monitoring of premature loss of primary teeth that began when the child was 5 years old. On presentation his teeth were mobile and there was a history of gingival bleeding. Panoramic radiography revealed generalized and severe bone loss, and the teeth showed no bony support enough for their stability. Blood test was ordered to assess the overall health of the child and giant cells with cytoplasmic granules were found, confirming the diagnosis of CHS. The management of periodontal disease focused on the control of infection and bacterial plaque by mechanical and chemical methods.

  14. A review on vital pulp therapy in primary teeth.

    PubMed

    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.

  15. Detail from roadbed showing sprocket teeth in rolling segment and ...

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

    Detail from roadbed showing sprocket teeth in rolling segment and typical lateral bracing. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  16. Astronauts Culbertson and Bursch brush their teeth on Discovery's middeck

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronauts Frank L. Culbertson (right), mission commander, and Daniel W. Bursch, mission specialist, brush their teeth on Discovery's middeck. Two sleep restraints form part of the backdrop for the photograph.

  17. Accuracy of three-dimensional printing for manufacturing replica teeth

    PubMed Central

    Lee, Keun-Young; Cho, Jin-Woo; Chang, Na-Young; Chae, Jong-Moon; Kang, Kyung-Hwa; Kim, Sang-Cheol

    2015-01-01

    Objective Three-dimensional (3D) printing is a recent technological development that may play a significant role in orthodontic diagnosis and treatment. It can be used to fabricate skull models or study models, as well as to make replica teeth in autotransplantation or tooth impaction cases. The aim of this study was to evaluate the accuracy of fabrication of replica teeth made by two types of 3D printing technologies. Methods Fifty extracted molar teeth were selected as samples. They were scanned to generate high-resolution 3D surface model stereolithography files. These files were converted into physical models using two types of 3D printing technologies: Fused deposition modeling (FDM) and PolyJet technology. All replica teeth were scanned and 3D images generated. Computer software compared the replica teeth to the original teeth with linear measurements, volumetric measurements, and mean deviation measurements with best-fit alignment. Paired t-tests were used to statistically analyze the measurements. Results Most measurements of teeth formed using FDM tended to be slightly smaller, while those of the PolyJet replicas tended to be slightly larger, than those of the extracted teeth. Mean deviation measurements with best-fit alignment of FDM and PolyJet group were 0.047 mm and 0.038 mm, respectively. Although there were statistically significant differences, they were regarded as clinically insignificant. Conclusions This study confirms that FDM and PolyJet technologies are accurate enough to be usable in orthodontic diagnosis and treatment. PMID:26445716

  18. Teeth in the cerebellopontine angle: an unusual dermoid tumour.

    PubMed

    Amirjamshidi, A; Ghodsi, M; Edraki, K

    1995-01-01

    An hour-glass-shaped multidensity lesion found by CT in a 6-year-old boy who had been admitted to the emergency department after a mild car accident. This lesion turned out to be a congenital dermoid tumour of the right cerebellopontine angle-tentorial notch region containing 12 mature teeth and 14 pseudocarilagenous structures. This is the first case of dermoid tumour containing so many teeth, reported in an asymptomatic person and located off the midline.

  19. Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

    PubMed

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  20. Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

    PubMed Central

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions. PMID:25202746