Unusual extraction treatment in Class II division 1 using C-orthodontic mini-implants.

PubMed

Chung, Kyu-Rhim; Cho, Jae-Hee; Kim, Seong-Hun; Kook, Yoon-Ah; Cozzani, Mauro

2007-01-01

This paper describes the treatment of a female patient, aged 23 years and 5 months, with a Class II division 1 malocclusion, who showed severe anterior protrusion and lower anterior crowding. Specially-designed orthodontic mini-implants were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. Both lower first molars showed severe apical lesions. Therefore, the treatment plan consisted of extraction of both upper first premolars and lower first molars, en masse retraction of the upper six anterior teeth, lower anterior alignment, and protraction of all the lower molars. C-implants(R) were used as substitutes for maxillary posterior anchorage teeth during anterior retraction and as hooks for mandibular molar protraction. The correct overbite and overjet were obtained by intruding and retracting the upper six anterior teeth into their proper positions. The dentition was detailed using conventional orthodontic appliances. The upper C-implants contributed to an improvement in facial balance, and the lower C-implants made it possible to protract the lower second and third molars with less effect on the axis of the lower anterior teeth. The active treatment period was 29 months and the patient's teeth continued to be stable 11 months after debonding.

[Three-dimensional finite element analysis of maxillary anterior teeth retraction force system in light wire technique].

PubMed

Zhang, Xiangfeng; Wang, Chao; Xia, Xi; Deng, Feng; Zhang, Yi

2015-06-01

This study aims to construct a three-dimensional finite element model of a maxillary anterior teeth retraction force system in light wire technique and to investigate the difference of hydrostatic pressure and initial displacement of upper anterior teeth under different torque values of tip back bend. A geometric three-dimensional model of the maxillary bone, including all the upper teeth, was achieved via CT scan. To construct the force model system, lingual brackets and wire were constructed by using the Solidworks. Brackets software, and wire were assembled to the teeth. ANASYS was used to calculate the hydrostatic pressure and the initial displacement of maxillary anterior teeth under different tip-back bend moments of 15, 30, 45, 60, and 75 Nmm when the class II elastic force was 0.556 N. Hydrostatic pressure was concentrated in the root apices and cervical margin of upper anterior teeth. Distal tipping and relative intrusive displacement were observed. The hydrostatic pressure and initial displacement of upper canine were greater than in the central and lateral incisors. This hydrostatic pressure and initial intrusive displacement increased with an increase in tip-back bend moment. Lingual retraction force system of maxillary anterior teeth in light wire technique can be applied safely and controllably. The type and quantity of teeth movement can be controlled by the alteration of tip-back bend moment.

Site specific mineral composition and microstructure of human supra-gingival dental calculus.

PubMed

Hayashizaki, Junko; Ban, Seiji; Nakagaki, Haruo; Okumura, Akihiko; Yoshii, Saori; Robinson, Colin

2008-02-01

Dental calculus has been implicated in the aetiology of several periodontal conditions. Its prevention and removal are therefore desirable clinical goals. While it is known that calculus is very variable in chemical composition, crystallinity and crystallite size little is known about site specific variability within a dentition and between individuals. With this in mind, a study was undertaken to investigate the comparative site specific nature and composition of human dental supra-gingival dental calculus obtained from 66 male patients visiting for their dental check-up using fluorescent X-ray spectroscopy, X-ray diffractometry and Fourier transform infrared spectroscopy. The supra-gingival dental calculus formed on the lingual surfaces of lower anterior teeth and the buccal surfaces of upper molar teeth were classified into four types based on calcium phosphate phases present. There was significant difference in composition of the crystal phase types between lower and upper teeth (p<0.01). There was no significant difference in crystal size between dental calculus on anterior or molar teeth of all samples. The degree of crystallinity of dental calculus formed on the upper molar teeth was higher than that formed on the lower anterior teeth (p<0.01). The CO(3)(2-) contents in dental calculus formed on the lower anterior teeth were higher than on upper molar teeth (p<0.05) which might explain the difference in crystallinity. Magnesium and Si contents and Ca:P ratio on the other hand showed no significant difference between lower and upper teeth. It was concluded that the crystal phases, crystallinity and CO(3)(2-) contents of human dental supra-gingival dental calculus is related to its location in the mouth.

Enamel Demineralization during Fixed Orthodontic Treatment - Incidence and Correlation to Various Oral-hygiene Parameters.

PubMed

Lovrov, Sylvia; Hertrich, Klaus; Hirschfelder, Ursula

2007-09-01

To investigate the incidence of white spot lesions (WSLs) around brackets and molar bands during orthodontic therapy, and establish whether a correlation to indices of dental and gingival health, fluoride application and oral hygiene could be demonstrated. Fifty-three patients with fixed orthodontic appliances were included at random in this study at the Department of Orthodontics of Erlangen-Nuremberg University. Dental health (DMFS), plaque index, papillary bleeding index, sulcus probing depth (SPD), gingival recession (GR), clinical attachment level (as sum of SPD and GR), oral hygiene, and fluoride use were evaluated. WSLs were graded from intraoral photographs taken before and after treatment. 97.5% of teeth before and 73.6% after treatment were free of WSLs. Of all teeth, 24.9% developed new WSLs or a rise in their number. New or more numerous WSLs were more common in upper and lower premolars (34.4%) and front teeth (28.1%) than molars (11.8%). WSL incidence during therapy correlated with clinical attachment level, and the oral hygiene and fluoride-use scores. Despite improvements in materials and preventive efforts, orthodontic treatment continues to carry the considerable risk of enamel demineralization. Each patient's prophylactic efforts, including fluoride use, are of paramount importance in preventing WSLs.

At first glance: social meanings of dental appearance.

PubMed

Eli, I; Bar-Tal, Y; Kostovetzki, I

2001-01-01

An important factor in social interaction is physical appearance. Major elements in the evaluation of physical appearance are the mouth and teeth. The purpose of this study was to evaluate the effect of tooth appearance on the development of a first impression of the other person, with regard to the sex of both the respondent and the target. Eight facial photographs of individuals with intact upper teeth were manipulated: one set was left untouched and the other was professionally altered so that the front anterior teeth appeared decayed. The photographs were randomly aligned in sets of eight, each set consisting of four individuals with an original, intact dentition and four other individuals with a "decayed" dentition. The sets of photographs were then presented to 115 respondents (65 males and 50 females). Evaluations were made according to three categories of traits--esthetic, social, and professional. For all three evaluation categories, the difference in scores between decayed and intact dentition given to targets were significantly higher when participants of one sex evaluated targets of the opposite sex, as compared to evaluating targets of their own sex. The effect of tooth appearance on the physical attractiveness stereotype is more evident when males evaluate females and vice versa, rather than when evaluating their own sex.

"All I want for Christmas is my two front teeth" (the story behind the song).

PubMed

Christen, Arden G; Christen, Joan A

2006-01-01

During his long and productive career, Donald Yetter Gardner (1913-2004) played various musical instruments, directed church choirs, wrote contemporary church anthems and led many community-sponsored choral events. Additionally, he penned a number of popular spirituals, including "Man Shall Not Live By Bread Alone," and "O Give Thanks Unto the Lord". He was noted for his varied musical accomplishments, but he was best known for composing what was to become an international childrens holiday favorite, "All I Want For Christmas Is My Two Front Teeth".

[Torque control evaluated by lateral cephalometric radiography and cone-beam CT after retraction of the upper anterior teeth].

PubMed

Yang, Xue; Qian, Yu-Fen

2016-08-01

To investigate the relationship between torque control and movement type of the teeth and to investigate the correlation between reconstruction of the alveolar bone and retraction of the upper anterior teeth. Cephalograms of pre-treatment and post-treatment of 111 cases and cone-beam computed tomography of pre-retraction and post-retraction of 7 cases were collected. The inclination degree of the upper anterior teeth, the horizontal and vertical displacement of edge and apex,and the thickness of the alveolar bone at the apex level were measured. Student's t test and Pearson χ2 test were performed for statistical analysis with SAS 8.02 software package. Cases who received torque control during the period of retraction displayed less change of inclination degree of the upper anterior teeth, less lingual displacement of the edge, more lingual displacement of the apex. The total thickness of the alveolar bone at the apex level and the length of the teeth significantly decreased after retraction(P<0.05). The amount of the alveolar bone rebuilt after retraction was less than that of the tooth movement, and there was no significant difference between teenagers and adults. During retraction of the upper anterior teeth, cases who received torque control showed less inclination degree change of the upper anterior teeth, less lingual displacement of the edge, more lingual displacement of the apex. More bodily movement and partially controlled tipping movement as well as higher incident rate of severe root resorption would also arise. There was correlation between reconstruction of the alveolar bone and the tooth movement. Since the amount of adaptive reconstruction of the lingual alveolar bone was limited, and there was no difference between teenagers and adults, excessive lingual displacement would surpass its adaption ability, and gave rise to alveolar bone and tooth damage.

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

PubMed

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

2017-04-01

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

[Comparative study of the fracture resistance of sound upper premolars and upper premolars restored with bonded amalgam].

PubMed

Minto, André Marcelo Peruchi; Dinelli, Welingtom; Nonaka, Tomio; Thome, Luis Henrique de Camargo

2002-01-01

The purpose of this in vitro study was to determine the fracture resistance of upper premolars which had received class II preparations (conservative and extensive) and were restored with bonded amalgam, with two different adhesive systems. Seventy teeth were divided in four groups: group 1 (control), with ten sound teeth; group 2, with twenty prepared teeth (10 teeth received conservative cavities and 10, extensive cavities) restored with amalgam without any kind of liner; groups 3 and 4, similar to group 2, though with linings of glass ionomer cement (Vitrebond - 3M) (group 3) and dental adhesive (Scotchbond Multi-Purpose Plus - 3M) (group 4). The teeth were previously fixed in PVC cylinders with acrylic resin. After being restored and thermocycled, the test specimens were submitted to fracture by means of compression in an EMIC-MEM 2000 universal testing machine. After the application of the analysis of variance and complementary Tukey's test, we concluded that the utilized adhesive systems produced an increase of the fracture resistance of teeth presenting with conventional cavities; the teeth presenting with conservative cavities were more resistant in all experimental situations.

Comparison of onset anesthesia time and injection discomfort of 4% articaine and 2% mepivacaine during teeth extractions

PubMed Central

Gazal, Giath; Alharbi, Rashdan; Fareed, Wamiq Musheer; Omar, Esam; Alolayan, Albraa Badr; Al-Zoubi, Hassan; Alnazzawi, Ahmad A.

2017-01-01

Objective: To investigate the speed of action and injection discomfort of 4% articaine and 2% mepivacaine for upper teeth extractions. Materials and Methods: Forty-five patients were included in the articaine 4% group, and 45 in the mepivacaine 2% control group. After all injections, soft and hard tissue numbness was objectively gauged by dental probe at intervals of 15 s. Furthermore, the discomfort of the injections were recorded by the patients after each treatment on standard 100 mm visual analog scales, tagged at the endpoints with “no pain” (0 mm) and “unbearable pain” (100 mm). Results: There were significant differences in the meantime of first numbness to associated palatal mucosa and tooth of patients between mepivacaine and articaine buccal infiltration (BI) groups P = 0.01 and 0.01. Patients in the articaine group recorded earlier palatal mucosa and teeth numbness than those in the mepivacaine group. With regards to the discomfort of the needle injections, palatal injection was significantly more painful than BI (t-test: P < 0.001). Articaine buccal injection was significantly more painful than mepivacaine buccal injection (t-test: P <0.001). However, articaine palatal injection was less painful than articaine BI. Clinically, anesthesia onset time was faster in anterior upper teeth than upper middle and posterior teeth. Conclusions: BIs with 4% articaine was faster in achieving palate and teeth anesthesia than 2% mepivacaine for extraction of upper maxillary teeth. Patients in mepivacaine BI and articaine palatal injection groups reported less pain with needle injection. Failure of anesthesia was noticeable with maxillary multiple-rooted teeth. PMID:28442952

Sexual dimorphism in teeth? Clinical relevance.

PubMed

Radlanski, Ralf J; Renz, Herbert; Hopfenmüller, Werner

2012-04-01

Many morphometric studies show a sexual dimorphism in human teeth. We wanted to know whether it is possible to determine the sex of an individual if only the anterior teeth are visible. Fifty intraoral photographs showing the front tooth region of female and male individuals (age: from 7 to 75 years) were randomly arranged in actual size on a questionnaire. The lip region was covered in each case. Besides "female" and "male", one was also able to check "?" if undecided. The questionnaires were distributed to 50 expert test persons (dentists, dental technicians, dental assistants, and students of dental medicine) and to 50 laymen and were all returned for evaluation. Although the correct sex was recognized on single photographs to a maximum of 76%, it was incorrect in 69% on other photographs. Altogether, the statistical evaluation showed that in most cases, the sex was only recognized correctly by one half, and incorrect by the other half. It can be concluded that a sexual dimorphism of human teeth-although measurable morphometrically-could not be recognized visually on the basis of photographs of the front tooth region. Neither experts in the field of dentistry nor laymen were able to properly distinguish between male and female teeth.

Assisted eruption of impacted teeth into an alveolar bone graft in a patient with cleft lip and palate.

PubMed

Peamkaroonrath, Chonthicha; Manosudprasit, Montien; Godfrey, Keith

2008-11-01

To assist the eruption of impacted upper teeth into an alveolar bone graft in a patient with a unilateral cleft lip and palate. An 8-year-old Thai boy with left unilateral complete cleft lip and palate had the chief complaint of anterior crossbite. He presented with a mild skeletal 3, dental Class III subdivision malocclusion, anterior crossbite, left unilateral posterior crossbite, moderate crowding in the upper arch with impaction of upper the left lateral incisor (tooth 22) and canine (tooth 23). In the first phase of treatment the posterior crossbite was corrected with a removable appliance with a 3-way screw. In the second phase the impacted teeth were surgically exposed, moved into the alveolar bone graft and the teeth aligned with fixed appliances. The upper left lateral incisor was extracted because of its questionable longevity. The orthodontic treatment resulted in normal overjet, overbite and an acceptable facial profile. A prosthesis replaced tooth 22. Forced eruption of impacted teeth can be carried out successfully in the cleft patients after an appropriate treatment plan has been formulated and following preparation of alveolar bone graft in the cleft site.

[Root resorption after orthodontic treatment: a study of age factor and prevalence in anterior teeth].

PubMed

Tian, Yu-lou; Wang, Kun; Wang, Jing; Liu, Fang; Piao, Mei-ling

2013-04-01

To investigate the impact of age factor on root resorption and the prevalence in anterior teeth during orthodontic treatment. Sixty extraction cases treated with straight wire appliance were divided into adult group and child group, with 30 cases in each group.The panoramic radiographs pre-treatment and post-treatment were examined to measure the degrees of root resorption. A total of 360 anterior teeth in each group were evaluated. SPSS 13.0 software package was applied to perform statistical analysis. There was significant difference in root resorption index before and after treatment(P<0.01). The incidence of root resorption increased remarkably after orthodontic treatment. There was significant difference in the degree of root resorption in two groups (P<0.01). The prevalence of root resorption in anterior teeth was: upper central incisors, upper lateral incisors, lower central incisors, lower lateral incisors, upper canines and lower canines. The root resorption in adult patients are more obvious than child patients. The prevalence of root resorption in anterior teeth is different. Moderate or severe root resorption is prone to happen in upper central incisors or lateral incisors in adult patients.

Overjet and overbite analysis during the eruption of the upper permanent incisors.

PubMed

Cuoghi, Osmar A; Sella, Rodrigo C; Mamede, Igo; de Macedo, Fernanda A; Miranda-Zamalloa, Yésselin M; de Mendonça, Marcos R

2009-01-01

ABSTRACT The purpose of this study was to analyze the overjet and overbite behavior during eruption of the upper permanent incisors. Fourth-eight plaster casts of 16 patients from ages 6-13 years were appraised longitudinally. It was found that the overjet remains constant, starting at the eruption of the upper permanent central incisors until eruption of the upper permanent canine teeth, while the overbite increases after eruption of the upper permanent lateral incisors and remains constant with the eruption of the canine teeth.

[Prosthetic rehabilitation of patients with parodontitis based upon the use of 3D-technologies--clinical case example].

PubMed

Riakhovskiĭ, A N

2011-01-01

Clinical case of prosthetic rehabilitation of patient (female) with generalized parodontitis complicated by defects and deformations of dentitions was offered. Using 3D-technologies position of teeth was corrected with the help of a series of temporary transparent splints-modifiers with subsequent guy splintage and esthetic 3D-planning of front teeth forms. Teeth forms correction was made by composite using preliminary prepared templet.

[Combination of periodontal, orthodontic and endodontic therapy in upper anterior teeth with hopeless prognosis and long-time follow-up: a case report].

PubMed

Li, Y; Xu, L; Zhou, Y H; Ouyang, X Y; Cao, T

2017-08-18

It is complicated to decide the treatment plan of hopeless anterior teeth in esthetic zone due to severe periodontitis, periodontal-endodontic combined lesion or teeth trauma. The optional treatment plan for this kind of teeth includes retention after periodontal treatment, extraction and implant treatment, extraction and prosthodontic treatment and so on. To make an appropriate treatment plan, patients' periodontal conditions, periodontal biotype, local anatomy, esthetic demand, economic condition and social psychological status should be comprehensively considered. A combine of periodontal, endodontic and orthodontic therapy may achieve a good treatment effect in hopeless anterior teeth with severe periodontal destruction, tooth extrusion and occlusal trauma. In this case, a 20-year-old female who presented with symptoms of bleeding on brushing and upper incisors loosening for 1 month came to the Department of Periodontology, Peking University School and Hospital of Stomatology. The clinical examinations revealed that the patient's right upper incisor had signs of mobility (III°), intrusion of 1-2 mm, and probing depth (PD) of 9-10 mm. The periapical radiograph showed that the alveolar bone of right upper incisor absorbed horizontally to the apex. And the patients showed Angle II° malocclusion with II° overbite in anterior teeth and maxillary protrusion. A diagnosis of aggressive periodontitis and Angle II° malocclusion was made. The treatment of this patient lasts for 5 years which include periodontal initial therapy, orthodontic therapy, guided tissue regeneration (GTR) of right upper incisor and supportive periodontal therapy and the clinical result is fine. A hopeless upper incisor was successfully retained and the longtime clinical condition was stable. The strategy of retention of hopeless upper anterior teeth, the relationship of periodontal treatment and orthodontic treatment, and the indications of periodontal and orthodontic combined therapy were also discussed on the basis of this case. Generally, the positive factors in retention of hopeless teeth includes young age, absence of systemic conditions, strong motivation for maintaining the tooth, single root anatomy, integrated dentition, good response to cause-related therapy, intrabony alveolar bone defect, thick periodontal biotype, and regular supportive periodontal therapy. And in the progress of orthodontic therapy, regular supportive periodontal therapy and good plaque control is extremely important.

Teeth eruption in children with normal occlusion and malocclusion.

PubMed

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

2008-06-01

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

Malocclusion of teeth (image)

MedlinePlus

Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Malocclusion is the most common reason for referral to an orthodontist. Most malocclusion is mild enough not to ...

Apical root resorption during orthodontic treatment. A prospective study using cone beam CT.

PubMed

Lund, Henrik; Gröndahl, Kerstin; Hansen, Ken; Gröndahl, Hans-Göran

2012-05-01

To investigate the incidence and severity of root resorption during orthodontic treatment by means of cone beam computed tomography (CBCT) and to explore factors affecting orthodontically induced inflammatory root resorption (OIIRR). CBCT examinations were performed on 152 patients with Class I malocclusion. All roots from incisors to first molars were assessed on two or three occasions. At treatment end, 94% of patients had ≥1 root with shortening >1 mm, and 6.6% had ≥1 tooth where it exceeded 4 mm. Among teeth, 56.3% of upper lateral incisors had root shortening >1 mm. Of upper incisors and the palatal root of upper premolars, 2.6% showed root shortenings >4 mm. Slanted surface resorptions of buccal and palatal surfaces were found in 15.1% of upper central and 11.5% of lateral incisors. Monthly root shortening was greater after 6-month control than before. Upper jaw teeth and anterior teeth were significantly associated with the degree of root shortening. Gender, root length at baseline, and treatment duration were not. Practically all patients and up to 91% of all teeth showed some degree of root shortening, but few patients and teeth had root shortenings >4 mm. Slanted root resorption was found on root surfaces that could be evaluated only by a tomographic technique. A CBCT technique can provide more valid and accurate information about root resorption.

Individual factors associated to malocclusion in adolescents.

PubMed

Rebouças, Adriana Gama; Zanin, Luciane; Ambrosano, Gláucia Maria Bovi; Flório, Flávia Martão

2017-11-01

The study aimed to identify the severity of malocclusions and associated factors among Brazilian adolescents. Data from 5,445 adolescents participating in the Brazilian Oral Health Survey (SBBrasil 2010) were evaluated, of which 4,276 were included in the study based on the inclusion criteria. The dependent variable was severe and very severe malocclusion, according to the Dental Aesthetic Index (DAI > 30). The independent variables were place of residence, macro-region, self-reported ethnicity, income, gender, schooling, access to dental care, untreated caries and front and back teeth loss due to caries. A hierarchical multiple logistical regression analysis was performed, considering the complex cluster sampling plan. Prevalence of severe/very severe malocclusions was 17.5%. After adjustments, black/brown ethnicity group (OR = 1.59, 95% CI: 1.09-2.34), lower household income (OR = 0.67, 95% CI: 0.55-0-82), front (OR = 2.32, 95% CI: 1.14-4.76) and back teeth (OR = 1.45, 95% CI: 1.14-1.84) loss due to caries were associated with the outcome. Therefore, we conclude that black/brown ethnicity, lower household income and greater number of front and back teeth loss due to caries increased the odds for severe/very severe malocclusion.

The oral health of upper income Americans.

PubMed

Bailit, Howard; Lim, Sungwoo; Ismail, Amid

2016-06-01

Limited information is available on the oral health status of upper income Americans (>400 percent of the FPL). They constitute 33 percent of the population and account for 53 percent of dental expenditures. Using 1999-2004 NHANES data, we examined differences in the mean number and percentage of decayed and filled permanent surfaces and missing teeth among age and family income groups. For upper income Americans, across age groups, the mean number of untreated decayed surfaces and missing teeth ranged from 0.2 to 0.5 and 2.6 to 3.3, respectively. The mean number of restored surfaces was low in children but extensive in adults. Income disparities increased with increasing age. Overall, upper income Americans have good oral health. Relatively few have untreated decayed surfaces or missing teeth. The reasons for the large number of restored surfaces in upper income adults require further research. Most upper income Americans are in good oral health, especially the 12-18 year cohort. As this group ages, the oral health of upper income adults is expected to improve. © 2015 American Association of Public Health Dentistry.

Orbital Winch

NASA Technical Reports Server (NTRS)

Hoyt, Robert (Inventor); Slostad, Jeffrey T. (Inventor); Frank, Scott (Inventor); Barnes, Ian M. (Inventor)

2016-01-01

Orbital winch having: lower and upper frames; spool having upper and lower flanges with lower flange attached to lower frame; axial tether guide mounted to upper frame; secondary slewing ring coaxial with spool and rotatably mounted to upper frame, wherein secondary slewing ring's outer surface has gearing; upper tether guide mounted to inner surface of secondary slewing ring; linear translation means having upper end mounted to upper frame and lower end mounted on lower frame; primary slewing ring rotatably mounted within linear translation means allowing translation axially between flanges, wherein primary slewing ring's outer surface has gearing; lower tether guide mounted on primary slewing ring's inner surface; pinion rod having upper end mounted to upper frame and lower end mounted to lower frame, wherein pinion rod's teeth engage primary and secondary slewing rings' outer surface teeth; and tether passing through axial, upper, and lower tether guides and winding around spool.

Multiple extraction patterns in severe discrepancy cases.

PubMed

Anderson, B D

1975-10-01

Thirty-five cases have been collected from colleagues which illustrate that removal of additional maxillary teeth, following first bicuspid extractions, can allow the successful resolution of difficult discrepancy and anchorage cases. Charts 1 and 2 describe the amounts of space that might be expected by removal of additional upper bicuspids, upper first molars, and upper second molars. The findings on upper second molars are admittedly limited. Anchorage values as expressed by an efficiency percentage were approximately what would be expected from a study of anchorage values of the roots of teeth. The removal of upper second bicuspids has a better anchorage efficiency potential than the upper first molar, but this may be overcome somewhat by the greater size of the molar. Clear guidance cannot be given as to which teeth to remove in a specific case, but it is the observation of the author that for cases that are still in full Class II following four bicuspid space closure, upper second bicuspid removal would be more helpful from an anchorage perspective, whereas for cases that are in end-to-end molar relationship or require only a few millimeters to move into Class I, the upper first molar might be the tooth of choice. Also, the supper first molar removal allows for a more "normal" appearing arch assuming normal alignment and size of the upper second and third molars. The comparison with the nonextraction control group showed an enormous difference in the amount of incisor retraction that extractions provide when related to the maxilla. The nonextraction control group, though experiencing dramatic correction of Class II relationships, showed no incisor movement within the maxilla. Some problems which appeared in the sample were described. Removal of upper teeth in addition to the four first bicuspids can be a solution to an occasional anchorage, skeletal, growth or cooperation problem.

Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population.

PubMed

Ivannikov, Alexander I; Khailov, Artem M; Orlenko, Sergey P; Skvortsov, Valeri G; Stepanenko, Valeri F; Zhumadilov, Kassym Sh; Williams, Benjamin B; Flood, Ann B; Swartz, Harold M

2016-12-01

The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y -1 , the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose-response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its variation correspond to 4.0 ± 0.4 (SD = 1.0) Gy. © Crown copyright 2016.

Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population

PubMed Central

Ivannikov, Alexander I.; Khailov, Artem M.; Orlenko, Sergey P.; Skvortsov, Valeri G.; Stepanenko, Valeri F.; Zhumadilov, Kassym Sh.; Williams, Benjamin B.; Flood, Ann B.; Swartz, Harold M.

2016-01-01

The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y−1, the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose–response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its variation correspond to 4.0 ± 0.4 (SD = 1.0) Gy. PMID:27412516

The radular apparatus of cephalopods

PubMed Central

Messenger, J. B.

1999-01-01

This paper describes the ontogeny, breakdown and absorption of the radular teeth of cephalopods and, for the first time, considers the function of the 'bolsters' or radular support muscles. The radular ribbon, which bears many regularly arranged transverse rows of teeth one behind the other, lies in a radular canal that emerges from the radular sac. Here the radular teeth are formed by a set of elongate cells with microvilli, the odontoblasts. These are organized into two layers, the outer producing the radular membrane and the bases of the teeth, the inner producing the cusps. The odontoblasts also secrete the hyaline shield and the teeth on the lateral buccal palps, when these are present. At the front end of the radular ribbon the teeth become worn in feeding and are replaced from behind by new ones formed continuously in the radular sac, so that the whole ribbon moves forward during ontogeny. Removal of the old teeth is achieved by cells in the radular organs; these cells, which are formed from modified odontoblasts ('odontoclasts'), dissolve the teeth and membranes and absorb them. There is a subradular organ in all cephalopods. In Octopus vulgaris, which bores into mollusc shells and crustacean carapaces, it is especially well-developed and there is also a supraradular organ. A characteristic feature of the cephalopod radular apparatus is the pair of large radular support muscles or 'bolsters'. Their function seems never to have been investigated, but experiments reported here show that when they elongate, the radular teeth become erect at the bending plane and splayed, presumably enhancing their ability to rake food particles into the pharynx. The bolsters of Octopus function as muscular hydrostats: because their volume is fixed, contraction of their powerful transverse muscles causes them to elongate. In decapods and in nautiloids each bolster contains a 'support rod' of semi-fluid material, as well as massive transverse musculature. This rod may elongate to erect the radular teeth. At the extreme front end of the bolsters in Octopus there are many nerve fibres that may constitute a receptor organ signalling the movements of the radula against hard material. Such nerves are absent from decapods and from octopods that do not bore holes. The buccal mass of Nautilus is massive, with heavily calcified tips to the beaks and a wide radular ribbon, with 13 rather than nine elements in each row. Nevertheless all the usual coleoid features are present in the radular apparatus and the teeth are formed and broken down in the same way. However, Nautilus has a unique structure, the radular appendage. This comprises a papillate mass extending over the palate in the mid-line and forming paired lateral masses that are in part secretory. The organ is attached to the front of the radula by muscles and connective tissue. Its function is unknown.

Characteristics of dental pulp in human upper first premolar teeth based on immunohistochemical and morphometric examinations.

PubMed

Tomaszewska, Joanna Maria; Miskowiak, Bogdan; Matthews-Brzozowska, Teresa; Wierzbicki, Piotr

2013-01-01

Teeth extracted for orthodontic reasons are commonly considered as healthy. Therefore, it is possible to examine structure of the dental pulp can be fully recognized and how it is affected by malocclusion. The aim of the study was to evaluate by immunohistochemistry (IHC) and morphometry dental pulp in human upper first premolar teeth extracted for orthodontic reasons. The material comprised 36 teeth of 20 patients in the age range 16-26 years. By the use of IHC markers the presence of immunocompetent cells (CD20, CD45RO, and CD68), blood vessels (CD31) and nerves (PGP9.5) were examined in the pulp. Inflammatory infiltrates and tissue atrophy were observed in 24 and 10 teeth, respectively. Strong positive correlation between the width of the odontoblastic layer, the number of rows of odontoblast nuclei and the increase of MVA (microvessel area) in the pulp of atrophic teeth was found. The cellular infiltrations found in H&E-stained sections were identified by IHC as memory T cells (CD45RO+) and B lymphocytes (CD20+) with macrophages (CD68+) present at the periphery. The CD20 antigen was intensively expressed in 13 teeth, CD45RO in 33 teeth, and CD68 in 20 teeth. Thus, despite the lack of any clinical signs of pulp disease many teeth extracted for orthodontic reasons show focal pulp inflammation and atrophy which probably results from the malocclusion stress accompanying teeth crowding.

Selection and constraint underlie irreversibility of tooth loss in cypriniform fishes

PubMed Central

Aigler, Sharon R.; Jandzik, David; Hatta, Kohei; Uesugi, Kentaro; Stock, David W.

2014-01-01

The apparent irreversibility of the loss of complex traits in evolution (Dollo’s Law) has been explained either by constraints on generating the lost traits or the complexity of selection required for their return. Distinguishing between these explanations is challenging, however, and little is known about the specific nature of potential constraints. We investigated the mechanisms underlying the irreversibility of trait loss using reduction of dentition in cypriniform fishes, a lineage that includes the zebrafish (Danio rerio) as a model. Teeth were lost from the mouth and upper pharynx in this group at least 50 million y ago and retained only in the lower pharynx. We identified regional loss of expression of the Ectodysplasin (Eda) signaling ligand as a likely cause of dentition reduction. In addition, we found that overexpression of this gene in the zebrafish is sufficient to restore teeth to the upper pharynx but not to the mouth. Because both regions are competent to respond to Eda signaling with transcriptional output, the likely constraint on the reappearance of oral teeth is the alteration of multiple genetic pathways required for tooth development. The upper pharyngeal teeth are fully formed, but do not exhibit the ancestral relationship to other pharyngeal structures, suggesting that they would not be favored by selection. Our results illustrate an underlying commonality between constraint and selection as explanations for the irreversibility of trait loss; multiple genetic changes would be required to restore teeth themselves to the oral region and optimally functioning ones to the upper pharynx. PMID:24821783

Variations in tooth size and arch dimensions in Malay schoolchildren.

PubMed

Hussein, Khalid W; Rajion, Zainul A; Hassan, Rozita; Noor, Siti Noor Fazliah Mohd

2009-11-01

To compare the mesio-distal tooth sizes and dental arch dimensions in Malay boys and girls with Class I, Class II and Class III malocclusions. The dental casts of 150 subjects (78 boys, 72 girls), between 12 and 16 years of age, with Class I, Class II and Class III malocclusions were used. Each group consisted of 50 subjects. An electronic digital caliper was used to measure the mesio-distal tooth sizes of the upper and lower permanent teeth (first molar to first molar), the intercanine and intermolar widths. The arch lengths and arch perimeters were measured with AutoCAD software (Autodesk Inc., San Rafael, CA, U.S.A.). The mesio-distal dimensions of the upper lateral incisors and canines in the Class I malocclusion group were significantly smaller than the corresponding teeth in the Class III and Class II groups, respectively. The lower canines and first molars were significantly smaller in the Class I group than the corresponding teeth in the Class II group. The lower intercanine width was significantly smaller in the Class II group as compared with the Class I group, and the upper intermolar width was significantly larger in Class III group as compared with the Class II group. There were no significant differences in the arch perimeters or arch lengths. The boys had significantly wider teeth than the girls, except for the left lower second premolar. The boys also had larger upper and lower intermolar widths and lower intercanine width than the girls. Small, but statistically significant, differences in tooth sizes are not necessarily accompanied by significant arch width, arch length or arch perimeter differences. Generally, boys have wider teeth, larger lower intercanine width and upper and lower intermolar widths than girls.

Periosteoplasty for covering gingival recessions: Clinical results

PubMed Central

Virnik, Sascha; Chiari, Friedrich Michael; Gaggl, Alexander

2009-01-01

This is a case series in which a new technique for the surgical treatment of periodontal recessions is presented along with the results of the first clinical trial. A new technique of periodontal flap surgery was performed on 30 patients with severe periodontal recessions of the upper or lower front teeth. Root and soft tissue scaling was carried out with an open approach, then the periosteum was incised and mobilized at the apical part of the mucoperiosteum flap to cover the defect before the mucoperiosteum was reattached and fixed by sutures. Sulcus bleeding, periodontal probing depths, attachment loss and the length of the attached gingiva of the affected teeth were recorded preoperatively and at 3, 6, and 12 months postoperatively. Every clinical parameter was improved by surgery. No sulcus bleeding was observed at any time during the postoperative follow-up. A mean reattachment of 5.5 mm was noticed 12 months postoperatively at a mean probing depth of 0.3 mm. The mean height of the attached gingiva was 0 mm before surgery, 2.3 mm at three and six months postoperatively, and 2.2 mm at 12 months. The periosteum eversion technique is suitable for the treatment of gingival recessions resulting in good gingival function and a clear improvement in aesthetics. PMID:23674900

Prevalence of vertical root fracture as the reason for tooth extraction in dental clinics.

PubMed

Yoshino, Koichi; Ito, Koji; Kuroda, Masahiko; Sugihara, Naoki

2015-07-01

The aim of this study was to investigate the prevalence, by gender, of vertical root fracture (VRF) as the main reason for the extraction of permanent teeth in dental clinics in Tokyo. Participating dentists were requested to provide information about extractions of permanent teeth they had performed from 1 January 2013 to 30 June 2013. The main reasons for extraction were categorized as follows: VRF, caries (horizontal root fracture included), periodontal disease and others. At a total of 24 clinics, 736 teeth were extracted from 626 patients during the 6-month period. A total of 233 teeth were extracted by VRF (31.7%), and 93.6% of these were endodontically treated teeth. Among non-vital extracted teeth, 82.1% (179/218) had cast posts or screw posts. The percentage of extraction due to VRF was 29.4% in males and 34.7% in females. In females, the percentage of extractions due to VRF (34.7%) was higher than for periodontal disease (28.1%). In males, the percentage of extractions due to VRF increased with age (p < 0.05). The tooth types with the highest percentage of extractions due to VRF were the upper canine (46.7%), lower second premolar (48.0%) and lower first molar (50.0%) in males and the upper first premolar (43.3%), upper second premolar (44.4%), lower second premolar (53.8%) and lower first molar (54.5%) in females. These results indicate that we need to pay more attention to maintaining vital teeth while being aware of the particular tooth types in which VRF most frequently occurs.

[A retrospective study of 180 cases of apical microsurgery].

PubMed

Wang, Hanguo; Li, Dan; Tian, Yu; Yu, Qing

2014-07-01

To evaluate the outcome and the potential prognostic factors of apical microsurgery. The teeth with persistent periapical diseases were treated by microsurgery using micro instruments, ultrasonic retrotips and mineral trioxide aggregate (MTA) under dental operate microscope. The procedure includes incision and flap retraction, osteotomy, apicoectomy, retro- preparation and retro- filling of root canal. Patients were recalled at 1, 3, 6, and 12- month intervals. The outcome was evaluated by clinical and radiographic examinations, and the potential prognostic factors were analyzed. One hundred and eighty cases (240 teeth), including 132 upper anterior teeth, 22 lower anterior teeth, 31 upper premolars, 18 lower premolars, 19 upper molars and 18 lower molars, were treated by microsurgery between July 2010 and December 2012. A total of 152 cases (207 teeth) were recalled. The application of the apical microsurgery included failure of previous endodontic treatment, periapical lesion with post, periapical cyst, calcified canals, separated instruments, overfilling, open apex, root facture, failure of previous apical surgery, apical fenestration, and special root canal system. The success rate was 90.8% (188/207). Age, sex, tooth position, type of periapical radiolucency, fistula and clinical application type appeared to have a negative effect on the outcome. Endo-perio lesion was a significant factor. Eighteen cases (19 teeth) failed mainly because of periodontally involved lesion and vertical root fracture. Apical microsurgery, which combines the magnification and illumination provided by the microscope with the proper use of micro instruments, can treat the teeth with persistent periapical diseases precisely and less traumatically with high success rate. Case selection and standardized operations play a key role for success.

Assessment of changes following en-masse retraction with mini-implants anchorage compared to two-step retraction with conventional anchorage in patients with class II division 1 malocclusion: a randomized controlled trial.

PubMed

Al-Sibaie, Salma; Hajeer, Mohammad Y

2014-06-01

No randomized controlled trial has tried to compare treatment outcomes between the sliding en-masse retraction of upper anterior teeth supported by mini-implants and the two-step sliding retraction technique employing conventional anchorage devices. To evaluate skeletal, dental, and soft tissue changes following anterior teeth retraction. Parallel-groups randomized controlled trial on patients with class II division 1 malocclusion treated at the University of Al-Baath Dental School in Hamah, Syria between July 2011 and May 2013. One hundred and thirty-three patients with an upper dentoalveolar protrusion were evaluated and 80 patients fulfilled the inclusion criteria. Randomization was performed using computer-generated tables; allocation was concealed using sequentially numbered opaque and sealed envelopes. Fifty-six participants were analysed (mean age 22.34 ± 4.56 years). They were randomly distributed into two groups with 28 patients in each group (1:1 allocation ratio). Following first premolar extraction, space closure was accomplished using either the en-masse technique with mini-implants or the two-step technique with transpalatal arches (TPAs). The antero-posterior displacements of upper incisal edges and upper first molars were measured on lateral cephalograms at three assessment times. Assessor blinding was employed. A bodily retraction (-4.42 mm; P < 0.001) with a slight intrusion (-1.53 mm; P < 0.001) of the upper anterior teeth was achieved in the mini-implants group, whereas upper anterior teeth retraction was achieved by controlled palatal tipping in the TPA group. When retracting anterior teeth in patients with moderate to severe protrusion, the en-masse retraction based on mini-implants anchorage gave superior results compared to the two-step retraction based on conventional anchorage in terms of speed, dental changes, anchorage loss, and aesthetic outcomes.

Differences in lightness, chroma, and hue in the anterior teeth of quinquagenarians and septuagenarians.

PubMed

Eiffler, Constantin; Cevirgen, Engin; Helling, Stephan; Zornek, Juanita; Pritsch, Maria; Hassel, Alexander Jochen

2010-10-01

The purpose of this study was to evaluate, for both genders and two elderly age groups, differences in lightness, chroma, and hue of pairs of natural anterior teeth, so that more accurate information on color would be available for the production of dentures with a natural appearance. The subjects in the younger group (YG) were 54 to 56 years of age, those in the older group 73 to 75 (N = 195, 48% women). Tooth color was measured using a spectrophotometer. Mixed models were calculated for each pair of teeth, with gender as a fixed factor. Gender did not have a significant effect in either age group. In both groups, differences in chroma between upper canines and lateral incisors and in lightness and hue between upper and lower canines were observed. In the YG, additional differences were found, with the only exception of the comparison between upper central and lateral incisors. The nongender-specific color differences observed should be considered when producing denture teeth for these groups of patients, in order to come as close as possible to the natural color ideal.

Upper and lower bounds for the speed of pulled fronts with a cut-off

NASA Astrophysics Data System (ADS)

Benguria, R. D.; Depassier, M. C.; Loss, M.

2008-02-01

We establish rigorous upper and lower bounds for the speed of pulled fronts with a cut-off. For all reaction terms of KPP type a simple analytic upper bound is given. The lower bounds however depend on details of the reaction term. For a small cut-off parameter the two leading order terms in the asymptotic expansion of the upper and lower bounds coincide and correspond to the Brunet-Derrida formula. For large cut-off parameters the bounds do not coincide and permit a simple estimation of the speed of the front.

Testosterone Buccal

MedlinePlus

... left and right of the two front teeth). Alternate sides at every dose so that you never ... thoughts or beliefs that have no basis in reality). People who use higher doses of testosterone than ...

14. UPPER STATION, FRONT AND WEST FACADES, LOOKING NORTHEAST. ...

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

14. UPPER STATION, FRONT AND WEST FACADES, LOOKING NORTHEAST. - Monongahela Incline Plane, Connecting North side of Grandview Avenue at Wyoming Street with West Carson Street near Smithfield Street, Pittsburgh, Allegheny County, PA

15. UPPER STATION, FRONT AND EAST FACADES, LOOKING NORTH. ...

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

15. UPPER STATION, FRONT AND EAST FACADES, LOOKING NORTH. - Monongahela Incline Plane, Connecting North side of Grandview Avenue at Wyoming Street with West Carson Street near Smithfield Street, Pittsburgh, Allegheny County, PA

Awareness of Dental Trauma Management among School Teachers of Kannur, Kerala, India

PubMed Central

Peedikayil, Faizal C; Premkumar, Chandru T; Narasimhan, Dhanesh; Jose, Deepak

2017-01-01

Introduction Dental trauma can overtake dental caries and periodontal disease as the most significant threat to dental health among young people. The prognosis of traumatized teeth depends on prompt and appropriate treatment. The role of school teachers in the prevention of traumatic dental injuries is a topic that has received a great deal of attention in recent years. However, studies conducted in different regions of the world have demonstrated that teachers and other lay people’s knowledge about traumatic dental injuries is inadequate and their behavior does not contribute to reduce the sequelae. Aim The purpose of this study was to evaluate the knowledge of school teachers about dental trauma and its management in Kannur district. Materials and Methods The survey was conducted under the Department of Paedodontics and Preventive Dentistry; Kannur Dental College among 303 school teachers randomly selected from 16 schools. Four schools were selected from 16 schools using stratified cluster sampling technique. A cross sectional study design was used. A stratified cluster sampling method was done to select the study subjects. The nature and purpose of the study was first explained to the teachers in local language. Following this the printed questionnaire was distributed to school teachers. The questionnaire was prepared based on the needs of the study after referring similar questionnaires used in studies conducted in different parts of the world. Results A statistically significant association was found between the teacher’s knowledge regarding trauma and their teaching experience. Out of the total school teachers who participated in the study, 90.1% responded correctly that the teeth most frequently affected by traumatic accidents are the upper front teeth. Nearly 23.4% responded correctly regarding management of traumatic tooth fracture. Almost 46.5% had correct knowledge regarding the reimplantation of avulsed permanent teeth. Only 14.2% responded correctly to the proper storage medium for avulsed teeth. Conclusion It was concluded from the study that among the school teachers surveyed there was significantly very low knowledge of emergency management of dental trauma. PMID:28384971

Unusual treatment of bimaxillary dentoalveolar protrusion via miniscrews and molar extraction

PubMed Central

Al-Fraidi, Ahmad; Afify, Ahmed R.

2012-01-01

This case report describes the treatment of a Saudi female patient, aged 13 years 8 months at the start of treatment, with a Class I bimaxillary dentoalveolar protrusion and extracted maxillary first molars. Miniscrews were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. The treatment plan consisted of extraction of both lower first permanent molars, distalization of upper and lower premolars using miniscrews followed by en masse retraction of the upper and lower six anterior teeth. The active treatment period was 2 years 8 months. Arch retention was done using upper wrap-around retainer and lower fixed 3-3 retainer. The use of miniscrews helped to resolve the bimaxillary protrusion regardless of extraction pattern used. PMID:24987626

2. EXTERIOR, SOUTH FRONT, UPPER LEVELS SHOWING ROOF CORNICE AND ...

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

2. EXTERIOR, SOUTH FRONT, UPPER LEVELS SHOWING ROOF CORNICE AND BAY WINDOW UNIT WITH PRESSED TIN SPANDREL - West Lexington Street, Number 314 (Commercial Building), 314 West Lexington Street, Baltimore, Independent City, MD

4. VIEW SOUTHWEST, LOWER STATION FRONT, INCLINE PLANE TRACK, UPPER ...

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

4. VIEW SOUTHWEST, LOWER STATION FRONT, INCLINE PLANE TRACK, UPPER STATION. - Monongahela Incline Plane, Connecting North side of Grandview Avenue at Wyoming Street with West Carson Street near Smithfield Street, Pittsburgh, Allegheny County, PA

5. VIEW SOUTHWEST, LOWER STATION FRONT, INCLINE PLANE TRACK, UPPER ...

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

5. VIEW SOUTHWEST, LOWER STATION FRONT, INCLINE PLANE TRACK, UPPER STATION. - Monongahela Incline Plane, Connecting North side of Grandview Avenue at Wyoming Street with West Carson Street near Smithfield Street, Pittsburgh, Allegheny County, PA

Supernumerary Teeth in Primary Dentition and Early Intervention: A Series of Case Reports

PubMed Central

Bahadure, Rakesh N.; Thosar, Nilima; Jain, Eesha S.; Kharabe, Vidhi; Gaikwad, Rahul

2012-01-01

Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stages. They are of great concern to the dentists and parents because of the eruption, occlusal, and esthetic problems they can cause. Supernumerary teeth occur more frequently in the permanent dentition but rarely in primary dentition. Mesiodens is the most common type of supernumerary teeth but rarely seen in lower arch. Early recognition and diagnosis of supernumerary teeth is important to prevent further complications in permanent dentition. Four cases of supernumerary teeth with mesiodens in upper and lower arch in primary dentition and their management have been discussed. PMID:22888456

A new record of blue-spotted seabream Pagrus caeruleostictus from Chinese coastal waters documented from morphology and DNA barcoding

NASA Astrophysics Data System (ADS)

Chen, Yongxia; Liu, Jing; Wu, Renxie

2015-03-01

A new record of Pagrus caeruleostictus (Valenciennes, 1830), collected from the Beibu Gulf, South China Sea in April 2013, was documented based on morphology and cytochrome oxidase I subunit (COI) gene barcoding analyses. It can be distinguished by a combination of the following characteristics: head scaled to above eyes; cheeks with 5 or 6 rows of scales; lateral line scales 51-52; 5 rows of scales above the lateral line; 4 and 6 cuspidate teeth in front of upper and lower jaws, respectively, followed by 2 rows of blunter teeth posteriorly; gill rakers on first arch 12 to 15; D XI-XII +9-11; A III +8-9; the first two dorsal spines very short, the third to fifth extended, filamentous in the young; the first pelvic ray filamentous; silvery pink with dark blue spots on back and sides; caudal fin pinkish; other fins bluish or pinkish; the blue spots generally disappear in large specimens. The present report of P. caeruleostictus suggests that its distribution in Chinese coastal waters may be attributed to human effort, since this species is unlikely to have expanded naturally from the eastern Atlantic to the South China Sea, with no other records from the Indian or Pacific Oceans. We recommend that a precautionary approach should be adopted for the management of P. caeruleostictus.

Sr-87/Sr-86 isotopic age determination of upper Cretaceous Santonian, Campanian and Maastrichtian chondrichthyan teeth of the Atlantic and Eastern Gulf Coastal Plains: Implications for sea level cyclicity and macrofossil time-averaging in depositional sequence lag deposits

NASA Astrophysics Data System (ADS)

Becker, Martin Andrew

1997-11-01

Unconformities and fossil rich layers are common elements in the stratigraphic architecture of upper Cretaceous sediments exposed on both the Atlantic and Eastern Gulf Coastal Plains. Contacts between the Eutaw Formation and Tombigbee Sands Member in Alabama, the Blufftown Formation and Cusseta Sands in Georgia and the Wenonah- Mt. Laurel and Navesink Formations in New Jersey are marked by erosional surfaces with overlying blankets and lenses of macrofossil residuum. These contacts correspond to bounding unconformities and transgressive lags separating Santonian-Campanian, lower Campanian-upper Campanian and Campanian-Maastrichtian depositional sequences. Regression and subsequent transgression of sea level at the top of these depositional sequences resulted in hydrodynamic sorting of sediments and fossils that had previously accumulated in shelf and lower shoreface paleoenvironments. Remobilization of sediments by shoreface retreat reworked fossil hard-parts which became concentrated above erosional surfaces as sea level rose. Because of the abundance of chondrichthyan, pelecypod and ammonite fossils, these lags have great biostratigraphic significance and provide a basis for examining time averaging in macrofossil zonation. Chondrichthyan teeth are composed of extremely durable and highly insoluble, biogenic apatite. This tooth apatite accurately records the Sr87/Sr86 isotopic signature of seawater, from which the numerical age of the teeth can be calculated using published age/concentration data. Teeth (e.g. Squalicorax kaupi, Scapanorhynchus texanus) from Santonian-Campanian lag deposits at the contact of the Eutaw Formation and Tombigbee Sands Member in Alabama yield approximate ages of 85-81 Ma. Teeth from lower-upper Campanian lag deposits at the contact of the Blufftown Formation and Cusseta Sands in Georgia yield approximate ages of 83-75 Ma. Teeth from Campanian-Maastrichtian lag deposits at the contact of the Wenonah-Mt. Laurel and Navesink Formations in New Jersey yield approximate ages of 80-76 Ma. Isotopic age determination from these chondrichthyan teeth indicate average hiatus of approximately 3-7 million years occur during the development of lag accumulations and transgressive unconformities. Santonian, Campanian and Maastrichtian macrofossils analyzed in this study are hydrodynamically stable components representing time-averaged fossil assemblages sorted together by physical processes and are not life cohorts. Abrupt appearance and disappearance of organisms found in upper Cretaceous lag deposits of the Atlantic and Eastern Gulf Coastal Plains are artifacts of a physical sorting processes associated with sea-level cyclicity.

Cephalometric analysis of the middle part of the face in patients with mandibular prognathism.

PubMed

Cutović Tatjana; Jović, Nebojsa; Kozomara, Ruzica; Radojicić, Julija; Janosević, Mirjana; Mladenović, Irena; Matijević, Stevo

2014-11-01

The middle part of the face, that is the maxilla, has always been mentioned as a possible etiologic factor of skeletal Class III. However, the importance of the relationship of maxillary retroposition towards the cranial base is still unclear, although it has been examined many times. The aim of this study was to conduct cephalometric analysis of the morphology of maxilla, including the whole middle part of the face in patients with divergent and convergent facial types of mandibular prognathism, as well as to determine differences betweeen them. Lateral cephalometric teleradiograph images of 90 patients were analyzed at the Dental Clinic of the Military Medical Academy, Belgrade, Serbia. All the patients were male, aged 18-35 years, not previously treated orthodontically. On the basis of dentalskeletal relations of jaws and teeth, the patients were divided into three groups: the group P1 (patients with divergent facial type of mandibular prognathism), P2 (patients with convergent facial type of mandibular pragmathism) and the group E (control group or eugnathic patients). A total of 9 cephalometric parameters related to the middle face were measured and analyzed: the length of the hard palate--SnaSnp, the length of the maxillary corpus--AptmPP, the length of the soft palate, the angle between the hard and soft palate--SnaSnpUt, the angle of inclination of the maxillary alveolar process, the angle of inclination of the upper front teeth, the effective maxillary length--CoA, the posterior maxillary alveolar hyperplasia--U6PP and the angle of maxillary prognathism. The obtained results showed that the CoA, AptmPP and SnaSnp were significally shorter in patients with divergent facial type of mandibular prognathism compared to patients with convergent facial type of the mandibular prognathism and also in both experimental groups of patients compared to the control group. SnaSnp was significantly shorter in patients with divergent facial type of mandibular prognathism compared to the control group, whereas SnaSnp was significantly smaller in patients with convergent facial type of mandibular prognathism compared to the control group. Additionally, there was a pronounced incisor dentoalveolar compensation of skeletal discrepancy in both groups of patients with mandibular prognathism manifested in the form of a significant upper front teeth protrusion, but without significant differences among the groups, while the maxillary retrognathism was present in most patients of both experimental groups. A pronounced UGPP was found only in the patients with divergent type of mandibular prognathism. The maxilla is certainly one of the key factors which contributes to making the diagnosis, but primarily to making a plan for mandibular prognathism treatment Accurate assessment of the manifestation of abnormality, localization of skeletal problems and understanding of the biological potential are key factors of the stability of/the results of surgical-orthodontic treatment of this abnormality.

Middle Pleistocene Climate Change Recorded in Fossil Mammal Teeth from Tarija, Bolivia, and Upper Limit of the Ensenadan Land-Mammal Age

NASA Astrophysics Data System (ADS)

MacFadden, Bruce J.

2000-07-01

Fossiliferous middle Pleistocene sediments of the Tarija basin of southern Bolivia contain a classic Ensenadan land-mammal fauna. New carbon isotopic data reported here for 50 specimens of the grazing mammals Equus (horse) and Cuvieronius (mastodon), documented from eight stratigraphic levels at Tarija, vary significantly in the δ13C values of their teeth. The pattern of variation appears to reflect the proportion of C3 and C4 grasses eaten during colder (more C3) and warmer (more C4) times. Within age limits set by associated magnetostratigraphy, the cold periods can be correlated with particular even-numbered stages in the marine oxygen-isotope record, and the warm periods can be correlated with odd-numbered stages. The oldest fossil teeth analyzed from the Tarija section can thereby be assigned to stage 29, and the youngest to stages 17 or 15, that is; the teeth range in age from about 1.1 myr to as young as 0.7 myr. Based on correlation of the upper part of the Tarija beds to the isotopic stages, the upper limit of the Ensenadan land-mammal age is between 0.7 and 0.6 myr, which is younger than stated in most previous studies.

[Thermometric diagnostics of chronic ulcerous pulpitis].

PubMed

Zvetkova, P; Mostrova, I

1989-01-01

Thermometric measurements were performed of 408 teeth of the upper and lower jaw with clinically confirmed initial and advanced stage of chronic ulcerous pulpitis in 398 subjects, aged from 18 to 30. Temperature elevation within the range from 1.4 to 3.2 degrees C was established in the initial form of chronic pulpitis and from 1 to 2.5 degrees C in advanced form of chronic pulpitis as compared with the norm. Significant difference in the temperature deviations exists in both forms of chronic pulpitis between the teeth of the upper and lower jaw.

Tissue Engineering of Necrotic Dental Pulp of Immature Teeth with Apical Periodontitis in Dogs: Radiographic and Histological Evaluation.

PubMed

El Ashiry, Eman A; Alamoudi, Najlaa M; El Ashiry, Mahmoud K; Bastawy, Hagar A; El Derwi, Douaa A; Atta, Hazem M

2018-05-15

To evaluate tissue engineering technology to regenerate pulp-dentin like tissues in pulp canals of immature necrotic permanent teeth with apical periodontitis in dogs. The study was performed on 36 teeth in 12 dogs. The experiment was carried out using split mouth design. In each dog 3 teeth were selected for implementing the study procedure. Apical periodontitis was induced in Group A and B teeth. Group (A): immature upper left 2 nd permanent incisors that were transplanted with a construct of autologous dental pulp stem cells with growth factors seeded in a chitosn hydrogel scaffold. Group (B): immature upper right 2 nd permanent incisor that received only growth factors with scaffold. A third tooth in each dog was selected randomly for isolation of dental pulp stem cells (DPSCs). Both groups were closed with a double coronal seal of white MTA (Mineral trioxide aggregate) and glass ionomer cement. Both groups were monitored radiographically for 4 months and histologically after sacrificing the animals. There was no statistically significant difference in radiographic findings between group (A) and group (B) for healing of radiolucencies, while there was statistically significant difference between group (A) and group (B) regarding radicular thickening, root lengthening and apical closure. Histologically, group (A) teeth showed regeneration of pulp-dentin like tissue while group (B) teeth did not show any tissue regeneration. Dental pulp stem cells and growth factors incorporated in chitosan hydrogel are able to regenerate pulp-dentine like tissue and help in complete root maturation of non-vital immature permanent teeth with apical periodontitis in dogs.

Obstructive sleep apnea syndrome in a pubescent boy of short stature was improved with an orthodontic mandibular advancement oral appliance: a case report.

PubMed

Ito, Shin; Otake, Hironao; Tsuiki, Satoru; Miyao, Etsuko; Noda, Akiko

2015-01-15

We report a 16-year-old pubescent pediatric patient with obstructive sleep apnea syndrome (OSAS) and short stature whose apnea hypopnea index (AHI) was significantly reduced following the use of an orthodontic oral appliance that advances the mandible ventrally. The mandible was advanced 64% of the maximal mandibular protrusive position with use of the appliance over a 3-year period. The patient's AHI without the appliance in place decreased from 101.6/h at baseline to 11/h after treatment. Moreover, the patient's height increased 14 cm during treatment, resulting in height close to the average height for his age. Cephalometric analysis revealed an improvement in his retrognathic mandible and proclination of the upper front teeth. In conclusion, an orthodontic mandibular advancement oral appliance played an important role not only in improving the patient's OSAS but also in normalizing his physical growth during puberty. © 2015 American Academy of Sleep Medicine.

Maxillary molar distalization with first class appliance

PubMed Central

Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

2014-01-01

Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation. PMID:24577171

75 FR 3150 - Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-20

... fractured front spar assembly for strut No. 3, which resulted in the loss of the strut upper link load path... of a fractured front spar assembly for strut No. 3, which resulted in the loss of the strut upper... loss of the strut upper link load path and consequent fracture of the diagonal brace, which could...

Enamel thickness variation of deciduous first and second upper molars in modern humans and Neanderthals.

PubMed

Fornai, Cinzia; Benazzi, Stefano; Svoboda, Jiří; Pap, Ildikó; Harvati, Katerina; Weber, Gerhard W

2014-11-01

Enamel thickness and dental tissue proportions have been recognized as effective taxonomic discriminators between Neanderthal and modern humans teeth. However, most of the research on this topic focused on permanent teeth, and little information is available for the deciduous dentition. Moreover, although worn teeth are more frequently found than unworn teeth, published data for worn teeth are scarce and methods for the assessment of their enamel thickness need to be developed. Here, we addressed this issue by studying the 2D average enamel thickness (AET) and 2D relative enamel thickness (RET) of Neanderthal and modern humans unworn to moderately worn upper first deciduous molars (dm(1)s) and upper second deciduous molars (dm(2)s). In particular, we used 3D μCT data to investigate the mesial section for dm(1)s and both mesial and buccal sections for dm(2)s. Our results confirmed previous findings of an Neanderthal derived condition of thin enamel, and thinner enamel in dm(1)s than dm(2)s in both Neanderthal and modern humans. We demonstrated that the Neanderthal 2D RET indices are significantly lower than those of modern humans at similar wear stages in both dm(1)s and dm(2)s (p < 0.05). The discriminant analysis showed that using 2D RET from dm(1) and dm(2) sections at different wear stages up to 93% of the individuals are correctly classified. Moreover, we showed that the dm(2) buccal sections, although non-conventionally used, might have an advantage on mesial sections since they distinguish as well as mesial sections but tend to be less worn. Therefore, the 2D analysis of enamel thickness is suggested as a means for taxonomic discrimination between modern humans and Neanderthal unworn to moderately worn upper deciduous molars. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cone Beam Computed Tomography-based Evaluation of the Anterior Teeth Position Changes obtained by Passive Self-ligating Brackets.

PubMed

Rhoden, Fernando K; Maltagliati, Liliana Á; de Castro Ferreira Conti, Ana C; Almeida-Pedrin, Renata R; Filho, Leopoldino C; de Almeida Cardoso, Maurício

2016-08-01

The objective of this study was to evaluate the anterior teeth position changes obtained by passive self-ligating brackets using cone beam computed tomography (CBCT). Twenty patients with a mean age of 16.5 years, class I malocclusion, constricted maxillary arch, and teeth crowding above 5 mm were enrolled in this study, and treated by passive orthodontic self-ligating brackets. A sequence of stainless steel thermoset wire was implemented with ending wire of 0.019" × 0.025". The CBCT and dental casts were obtained prior to the installation of orthodontic appliances (T1), and 30 days after rectangular steel wire 0.019" × 0.025" installation (T2). The measurements in CBCT were performed with the Anatomage software, and the dental casts were evaluated with a digital caliper rule with an accuracy of 0.01 mm. The CBCT data demonstrated mean buccal inclination of the upper and lower central incisors ranging from 6.55° to 7.24° respectively. The upper and lower lateral incisors ranged from 4.90° to 8.72° respectively. The lower canines showed an average increase of 3.88° in the buccal inclination and 1.96 mm in the transverse intercuspal distance. The upper canines showed a negative inclination with mean average of -0.36°, and an average increase of 0.82 mm in the transverse distance, with negative correlation with the initial crowding. Treatment with passive self-ligating brackets without obtaining spaces increases buccal inclination of the upper and lower incisors with no correlation with the amount of initial teeth crowding. The intercanine distance tends to a small increase showing different inclinations between the arches. When taking into account the self-ligating brackets, the amount of initial dental crowding is not a limitation factor that could increase the buccal inclination of the anterior teeth.

Use of the ditramax system to communicate esthetic specifications to the laboratory.

PubMed

Margossian, Patrice; Laborde, Gilles; Koubi, Stephen; Couderc, Gullaume; Mariani, Paul

2011-01-01

Prosthetic restoration of the anterior teeth is a major esthetic challenge. Esthetic treatment consists of creating pleasantly proportioned teeth and integrating them harmoniously into the patient's gingiva, lips, and face. The communication of clinical data to the laboratory is critical to the success of any esthetic treatment. The purpose here is to present a straightforward, efficient, and reproducible means of communicating esthetic specifications to ceramists, allowing them to work as though the patient was actually in front of them, with access to all of the major facial esthetic criteria.

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

PubMed

Xue, Dai Juan And Feng

2014-01-01

In this report we describe a combined orthodontic and surgical treatment for a 14-year-old boy with severe skeletal class III deformity and dental problem. His upper posterior primary teeth in the left side were over-retained and 6 maxillary teeth (bilateral central incisors and canines, left first and second premolars) were impacted, together with 5 supernumerary teeth in both arches. The treatment protocol involved extraction of all the supernumerary and deciduous teeth, surgical exposure and orthodontic traction of the impacted teeth, a bimaxillary orthognathic approach including Lefort I osteotomy. Bilateral sagittal split ramus osteotomy (BSSRO) and genioplasty was performed to correct skeletal problem. After treatment, all of the impacted teeth were brought to proper alignment in the maxillary arch. A satisfied profile and good posterior occlusion was achieved. Treatment mechanics and consideration during different stages are discussed.

Alternative method for predicting optimal insertion depth of the laryngeal tube in children.

PubMed

Kim, J T; Jeon, S Y; Kim, C S; Kim, S D; Kim, H S

2007-11-01

Little information is available about the accuracy of the teeth mark on the laryngeal tube (LT) as a guide to correct placement in children. The aim of this crossover study was to evaluate three methods for optimal insertion depth of the size (#) 2 tube in children weighing 12-25 kg. In 24 children, the LT #2 was consecutively inserted by three different methods: (A) until the thick teeth mark on the tube was aligned with the upper incisors, (B) until resistance was felt, and (C) by inserting to a depth, previously measured, of the curved distance between the cricoid cartilage and the upper incisor. In each case, the depth of insertion, the degree of effective ventilation, the presence of leakage, and the fibreoptic view were assessed. Insertion based on the teeth mark led to a shorter insertion depth and a greater incidence of inadequate ventilation compared with the other two methods. There was no difference in the adequacy of ventilation between methods B and C. The vocal cords were more easily identified with methods B (62.5%) and C (75%) than with method A (12.5%). Insertion of the LT #2 aligned with the teeth mark can result in a shallow insertion depth and inadequate ventilation. The measured distance from the cricoid cartilage to the upper incisor offers alternative guidance for correct LT insertion.

[Comparison between one-step and two-step space closing methods of sliding mechanics using three-dimensional finite element].

PubMed

Han, Yaohui; Mou, Lan; Xu, Gengchi; Yang, Yiqiang; Ge, Zhenlin

2015-03-01

To construct a three-dimensional finite element model comparing between one-step and two-step methods in torque control of anterior teeth during space closure. Dicom image data including maxilla and upper teeth were obtained though cone-beam CT. A three-dimensional model was set up and the maxilla, upper teeth and periodontium were separated using Mimics software. The models were instantiated using Pro/Engineer software, and Abaqus finite element analysis software was used to simulate the sliding mechanics by loading 1.47 Nforce on traction hooks with different heights (2, 4, 6, 8, 10, 12 and 14 mm, respectively) in order to compare the initial displacement between six maxillary anterior teeth (one-step method) and four maxillary anterior teeth (two-step method). When moving anterior teeth bodily, initial displacements of central incisors in two-step method and in one-step method were 29.26 × 10⁻⁶ mm and 15.75 × 10⁻⁶ mm, respectively. The initial displacements of lateral incisors in two-step method and in one-step method were 46.76 × 10(-6) mm and 23.18 × 10(-6) mm, respectively. Under the same amount of light force, the initial displacement of anterior teeth in two-step method was doubled compared with that in one-step method. The root and crown of the canine couldn't obtain the same amount of displacement in one-step method. Two-step method could produce more initial displacement than one-step method. Therefore, two-step method was easier to achieve torque control of the anterior teeth during space closure.

Effects of combining ozone and hydrogren peroxide on tooth bleaching: A clinical study.

PubMed

Al-Omiri, Mahmoud K; Hassan, Ra'ed S Abul; AlZarea, Bader K; Lynch, Edward

2016-10-01

The purpose of this study was to evaluate the efficiency of bleaching after combining ozone and 38% H2O2 in comparison to the sole use of 38% H2O2. Consecutive 26 participants (13 males and 13 females) were recruited into this study. They were randomly allocated into 2 groups (n=13 for each group). In group 1 (test group); the participants' upper anterior teeth were treated with 38% H2O2 for 20min then the teeth were exposed to ozone for 60s (healOzone(®) X4, KaVo Dental, Biberach, Germany). In group 2 (controls); the upper anterior teeth were treated with 20min of 38% H2O2 only. The shade of teeth was evaluated by recording the L* a* b* values and Vita Classic shades at study baseline and after bleaching in both groups. The statistically significant changes were set at P≤0.05. Tooth sensitivity and teeth shades were comparable between groups at study baseline (p>0.05). Controls reported more tooth sensitivity following bleaching (p<0.001). Teeth achieved better Vita shades, higher L* values (lighter shades), and lower a* and b* values (lighter shades) after bleaching in both groups (P≤0.05). However, teeth bleached with H2O2 and ozone achieved better Vita shades, higher L* values and lower a* values (lighter shades) than those bleached with H2O2 alone (p<0.001). Changes in b* values were not significantly different between groups. Bleaching with 38% H2O2 for 20min followed by 60s of ozone application would result in teeth with lighter shades than bleaching with 38% H2O2 alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Morphometry, Microstructure, and Wear Pattern of Neornithischian Dinosaur Teeth From the Upper Cretaceous Iharkút Locality (Hungary).

PubMed

Virág, Attila; Ősi, Attila

2017-08-01

Teeth of iguanodontian ornithopods and ceratopsians could be remarkably similar, thus the referral of isolated dental material to particular neornithischian clades can be highly problematic. These groups are represented by the rhabdodontid Mochlodon vorosi and the basal coronosaurian Ajkaceratops kozmai in the Upper Cretaceous Csehbánya Formation at Iharkút (western Hungary). Whereas teeth of Mochlodon are common elements at the locality, no dental material belonging to Ajkaceratops was identified until now. Here we used mathematical statistical approaches, as well as tooth wear and dental microstructure analysis in order to decide whether the teeth previously referred to Mochlodon can be treated as a homogenous sample, or some remains belong rather to Ajkaceratops. According to our results, there was a striking morphological and structural convergence between the teeth of both taxa. However, the wear study revealed the existence of two different patterns within the sample. One is characterized by straight and parallel microstriations that suggest orthal movements during the jaw closure. This pattern was associated with Mochlodon. The other pattern appeared only on a few teeth, and it can be differentiated by its distinctive curved microstriations that indicate circumpalinal chewing. Because curved striations have never been described in ornithopods, but are found in several neoceratopsians, this pattern was associated here with Ajkaceratops. Here we present the first teeth that can provisionally be referred to the latter genus. We believe that the methodology discussed in this article will facilitate distinguishing ceratopsian and ornithopod teeth in other localities as well. Anat Rec, 300:1439-1463, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Analysis of select facial and dental esthetic parameters.

PubMed

Nold, Sarah L; Horvath, Sebastian D; Stampf, Susanne; Blatz, Markus B

2014-01-01

This clinical study examined objective smile parameters in the natural anterior dentition. Standardized intraoral and extraoral photographs were taken of 106 Caucasian adults (54 women, 52 men) with a healthy dentition. The following parameters were analyzed: correlation of dental and facial midline, upper lip position and curvature, relationship of the maxillary anterior incisal curve with lower lip, number of teeth displayed in a smile, distance between maxillary anterior teeth and lower lip, slope of tooth, and lip arc. The simple frequency distribution of measured variables revealed an average smile with coinciding dental and facial midlines, an average smile line, and a straight upper lip curvature. With an average smile, the maxillary anterior teeth did not touch the lower lip, teeth were displayed up to the second premolar, and the maxillary anterior incisal curve was parallel to the lower lip. Oval was the most prevalent tooth form. A slope of 9 degrees was detected for the mean tooth arc and 13 degrees for the mean lip arc. The outcomes of this clinical study provide a quantifiable frame for esthetic evaluation, treatment planning, and restoration fabrication.

Using a smartphone as a tool to measure compensatory and anomalous head positions.

PubMed

Farah, Michelle de Lima; Santinello, Murillo; Carvalho, Luis Eduardo Morato Rebouças de; Uesugui, Carlos Fumiaki; Barcellos, Ronaldo Boaventura

2018-01-01

To describe a new method for measuring anomalous head positions by using a cell phone. The photo rotation feature of the iPhone® PHOTOS application was used. With the patient seated on a chair, a horizontal stripe was fixed on the wall in the background and a sagittal stripe was fixed on the seat. Photographs were obtained in the following views: front view (photographs A and B; with the head tilted over one shoulder) and upper axial view (photographs C and D; viewing the forehead and nose) (A and C are without camera rotation, and B and D are with camera rotation). A blank sheet of paper with two straight lines making a 32-degree angle was also photographed. Thirty examiners were instructed to measure the rotation required to align the reference points with the orthogonal axes. In order to set benchmarks to be compared with the measurements obtained by the examiners, blue lines were digitally added to the front and upper view photographs. In the photograph of the sheet of paper (p=0.380 and a=5%), the observed values did not differ statistically from the known value of 32 degrees. Mean measurements were as follows: front view photograph A, 22.8 ± 2.77; front view B, 21.4 ± 1.61; upper view C, 19.6 ± 2.36; and upper view D, 20.1 ± 2.33 degrees. The mean difference in measurements for the front view photograph A was -1.88 (95% CI -2.88 to -0.88), front view B was -0.37 (95% CI -0.97 to 0.17), upper view C was 1.43 (95% CI 0.55 to 2.24), and upper view D was 1.87 (95% CI 1.02 to 2.77). The method used in this study for measuring anomalous head position is reproducible, with maximum variations for AHPs of 2.88 degrees around the X-axis and 2.77 degrees around the Y-axis.

The heterodonty in euselachian sharks from the Pennsylvanian of Nebraska

NASA Astrophysics Data System (ADS)

Ginter, Michał

2016-09-01

Among the rich material of chondrichthyan microremains from the Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) near Peru, Nebraska, USA, housed at the Carnegie Museum of Natural History, there occur almost sixty teeth representing Euselachii. They belong to at least seven species, presenting various types of heterodonty. Two new species are described, viz. Ossianodus nebraskensis gen. et sp. nov., whose dentition is similar to that of certain Mesozoic hybodonts, and Sphenacanthus tenuis sp. nov. with minute teeth of protacrodont design. Most of the euselachian teeth served to crush or grind prey, and some had the potential to clutch, but cutting teeth are absent from the fauna.

Quantification of incisal tooth wear in upper anterior teeth: conventional vs new method using toolmakers microscope and a three-dimensional measuring technique.

PubMed

Al-Omiri, Mahmoud K; Sghaireen, Mohd G; Alzarea, Bader K; Lynch, Edward

2013-12-01

This study aimed to quantify tooth wear in upper anterior teeth using a new CAD-CAM Laser scanning machine, tool maker microscope and conventional tooth wear index. Fifty participants (25 males and 25 females, mean age = 25 ± 4 years) were assessed for incisal tooth wear of upper anterior teeth using Smith and Knight clinical tooth wear index (TWI) on two occasions, the study baseline and 1 year later. Stone dies for each tooth were prepared and scanned using the CAD-CAM Laser Cercon System. Scanned images were printed and examined under a toolmaker microscope to quantify tooth wear and then the dies were directly assessed under the microscope to measure tooth wear. The Wilcoxon Signed Ranks Test was used to analyze the data. TWI scores for incisal edges were 0-3 and were similar at both occasions. Score 4 was not detected. Wear values measured by directly assessing the dies under the toolmaker microscope (range = 113 - 150 μm, mean = 130 ± 20 μm) were significantly more than those measured from Cercon Digital Machine images (range=52-80 μm, mean = 68 ± 23 μm) and both showed significant differences between the two occasions. Wear progression in upper anterior teeth was effectively detected by directly measuring the dies or the images of dies under toolmaker microscope. Measuring the dies of worn dentition directly under tool maker microscope enabled detection of wear progression more accurately than measuring die images obtained with Cercon Digital Machine. Conventional method was the least sensitive for tooth wear quantification and was unable to identify wear progression in most cases. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

The giant keyhole limpet radular teeth: A naturally-grown harvest machine

PubMed Central

Ukmar-Godec, Tina; Kapun, Gregor; Zaslansky, Paul; Faivre, Damien

2015-01-01

The limpet radula is a feeding organ, which contains more than 100 rows of teeth. During their growth the teeth mature and advance in position along the radula. The simpler doccoglossan radulae operate by grinding rocky substrates, extracting the algae by rasping and scraping with the teeth functioning as shovels. Less is known about the rhipidoglossan radulae, used as rakes or brooms that brush and collect loose marine debris. This type of radula is found in the giant keyhole limpet (Megathura crenulata). The large size of this organism suggests that the rhipidoglossan radula entails a technological superiority for M. crenulata in its habitat. The structure and function of the radulae teeth have however not been reported in detail. Using a combination of 2D and 3D microscopy techniques coupled with amino acid analysis and X-ray scattering, we reveal the working components of M. crenulata’s radula. It is characterized by numerous marginal teeth surrounding a pair of major hook-like lateral teeth, two pairs of minor lateral teeth and a large central tooth. The mature major lateral teeth show pronounced signs of wear, which gradually increase towards the very front end of the radula and are evidence for scraping. An abrupt change in the amino acid composition in the major lateral teeth and the concurrent formation of a chitinous fiber-network mark the onset of tooth maturation. In comparison to the simpler rock-scraping doccoglossate limpets, the radula of M. crenulata forms an elaborate feeding apparatus, which can be seen as a natural harvest machine. PMID:26433029

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

PubMed

Busch, M; Kordass, B

2006-04-01

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

Two-Step Extraction of the Lower First Molar for Class III Treatment in Adult Patient.

PubMed

Almeida, Kélei Cristina de Mathias; Paulin, Ricardo Fabris; Raveli, Taísa Barnabé; Raveli, Dirceu Barnabé; Santos-Pinto, Ary

2016-01-01

The aim of this article is to describe a case report of Class III malocclusion treatment with lower first molar extraction. The 27-year-old Caucasian male patient presented a symmetric face with a straight profile, hyperdivergent growth pattern, molar and cuspid Class III relation, and an anterior crossbite as well as a mild crowding on cuspids area, in both upper and lower arches and a tendency to posterior crossbite. The treatment was performed by the use of Haas expansion appliance followed by an initial alignment and leveling of the upper and lower arches with a fixed edgewise appliance, extraction of lower teeth aiming the correction of the incisors proclination and end the treatment with a Class I molar relationship. It resulted in a significant change in the patient's profile, dentoalveolar Class III correction, upper arch expansion, leveling and alignment of the upper and lower arches, and improvement of tipping of the upper and lowers incisors. In cases of a dentoalveolar compensation in well positioned bone bases the treatment with fixed appliances is an alternative and extraction of lower teeth is considered.

Analysis of factors associated with cracked teeth.

PubMed

Seo, Deog-Gyu; Yi, Young-Ah; Shin, Su-Jung; Park, Jeong-Won

2012-03-01

The purpose of this study was to analyze the characteristics, distribution, and associated factors of longitudinal fractured teeth according to the well-defined criteria of the American Association of Endodontists (AAE). One hundred seven teeth with longitudinal fracture from 103 patients were diagnosed and analyzed. The patients' signs, symptoms, age, and sex were noted as well as the tooth number, dental arch, filling materials, size/classification of restoration, crack direction, pulp vitality, whether the patient had undergone endodontic treatment, bite test results, percussion test results, wear facet, and periodontal pocket depth. Eighty-seven teeth were diagnosed with a cracked tooth (81.3%), 14 were diagnosed with vertical root fracture (VRF, 13.1%), 4 had a split tooth (3.7%), and 2 had a fractured cusp (1.9%); 82.2% showed a sensitive reaction on the bite test. Longitudinal tooth fractures were observed most frequently in patient in their 40s. The upper first molar (28.0%) was most frequently cracked, followed by the lower first molar (25.2%), the lower second molar (20.6%), and the upper second molar (16.8%). Most longitudinal tooth fractures (72.0%) occurred mainly in restored teeth, whereas only 28.0% were found in intact teeth. Compared with resin (4.7%) or porcelain (0.9%), the use of nonbonded inlay restoration materials such as gold (20.5%) or amalgam (18.7%) increased the occurrence of longitudinal tooth fractures. Out of 107 of longitudinal fractured teeth, 33 (30.8%) were treated endodontically and 74 (69.2%) were not. VRF was associated with endodontic treatment. The bite test is most reliable for reproducing symptoms. The combined use of various examination methods is recommended for detecting cracks and minutely inspecting all directions of a tooth. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Awareness, attitudes, need and demand on replacement of missing teeth among a group of partially dentate patients attending a University Dental Hospital.

PubMed

Jayasinghe, Rasika Manori; Perera, Janana; Jayasinghe, Vajira; Thilakumara, Indika P; Rasnayaka, Sumudu; Shiraz, Muhammad Hanafi Muhammad; Ranabahu, Indra; Kularatna, Sanjeewa

2017-07-27

Our objective was to assess awareness, attitudes, need and demand on replacement of missing teeth according to edentulous space, age, gender, ethnicity, educational level and socio-economical status of the patient. 76.2% of the study group was opined that the missing teeth should be replaced by prosthetic means. Majority were keen in getting them replaced mainly for the comfort in mastication. Although 77.9 and 32.9% were aware of the removable prostheses and implants respectively, only 25.2% knew about tooth supported bridges as an option of replacement of missing teeth. Participants' awareness on tooth and implant supported prostheses is at a higher level. Participants' opinion on need of regular dental visit was statistically significant when gender, ethnicity and education level were considered. The highest demand for replacement of missing teeth was observed in Kennedy class I and II situations in both upper and lower arches. Demand for fixed prostheses was significantly highest in Kennedy class II in upper and lower arches. In conclusion, although removable prosthodontic options are known to most of the patients, their awareness on tooth and implant supported prostheses is also at a higher level. The highest demand for replacement of missing teeth is by patients with Kennedy class I and II situations whereas Kennedy class II being the category with highest demand for fixed prostheses. We recommend that the location of missing teeth to be considered as a priority when educating patients on the most appropriate prosthetic treatment options. Dentists' involvement in educating patients on prosthetic options needs to be improved.

Subduction at upper ocean fronts by baroclinic instability

NASA Astrophysics Data System (ADS)

Verma, Vicky; Pham, Hieu T.; Radhakrishnan, Anand; Sarkar, Sutanu

2017-11-01

Large eddy simulations of upper ocean fronts that are initially in geostrophic balance show that the linear and subsequent nonlinear evolution of baroclinic intability are effective in restratifying the front. During the growth of baroclinic instability, the front develops thin regions with enhanced vertical vorticity, i.e., vorticity filaments. Moreover, the vorticity filaments organize into submesoscale eddies. The subsequent frontal dynamics is dominated by the vorticity filaments and the submesoscale eddies. Diagnosis of the horizontal force balance reveals that the regions occupied by these coherent structures have significantly large imbalance, and are characterized by large vertical velocity. High density fluid from the heavier side of the front is subducted by the vertical velocity to the bottom of the mixed layer. The process of subduction is illustrated by Lagrangian tracking of fluid particles released at a fixed depth.

Determination of fracture toughness of human permanent and primary enamel using an indentation microfracture method.

PubMed

Hayashi-Sakai, Sachiko; Sakai, Jun; Sakamoto, Makoto; Endo, Hideaki

2012-09-01

The purpose of the present study was to examine the fracture toughness and Vickers microhardness number of permanent and primary human enamel using the indentation microfracture method. Crack resistance and a parameter indirectly related to fracture toughness were measured in 48 enamel specimens from 16 permanent teeth and 12 enamel specimens obtained from six primary teeth. The Vickers microhardness number of the middle portion was greater than the upper portion in primary enamel. The fracture toughness was highest in the middle portion of permanent enamel, because fracture toughness greatly depends upon microstructure. These findings suggest that primary teeth are not miniature permanent teeth but have specific and characteristic mechanical properties.

Pre-eruptive intracoronal resorption in a third upper molar: clinical, tomographic and histological analysis.

PubMed

Lenzi, R; Marceliano-Alves, M F; Alves, Frf; Pires, F R; Fidel, S

2017-06-01

Radiolucent or hypodense lesions in the crown of unerupted teeth may be due to pre-eruptive intracoronal resorption. Clinicians must be aware of this risk so that they can diagnose and appropriately treat this condition. The purpose of this study is to present a well-documented clinical case of pre-eruptive intracoronal resorption in an impacted third upper left molar of a 63 year old female patient. This was an unexpected finding, which occurred after cone-beam computed tomography was used to investigate the first upper left molar, which had an acute periradicular abscess. A multidisciplinary team followed up the case to describe clinical, radiographic and histological findings. The available treatment options were discussed, and the tooth extraction was the option chosen. Previous case studies describing such resorption in third upper molars have not been reported. This case shows that all permanent teeth in a pre-eruptive stage must be analysed radiographically to detect early pre-eruptive intracoronal resorption. © 2016 Australian Dental Association.

Orthodontic decompensation in class III patients by means of distalization of upper molars.

PubMed

Carlos, Villegas B; Giovanni, Oberti; Diego, Rey; Angela, Sierra; Baccetti, Tiziano

2009-01-01

Pre-surgical orthodontic treatments have the objective of establishing harmony between the dental arches by moving the teeth to ideal positions in relation to their bony bases, in order to achieve adequate antero-posterior occlusal and transverse relationships at the moment of surgery. Among the typical requirements in terms of dental compensations presented by Class III patients that require surgery, the inclination of anterior teeth must be changed in most cases by proclination of the lower incisors and retroclination of upper incisors. To achieve the inclination of the upper incisors, many different alternatives have been proposed, such as inter-proximal reduction, extractions, or distalization of upper molars, which has not been widely reported in the literature as a means to decompensate Class III malocclusion prior to surgery. This article describes the Bone Supported Pendulum (BSP) as an efficient therapeutic option to distalize molars through the use of an appliance stabilized to the palate by mini-implants, thus avoiding extractions and providing good interdigitation and coordination of the dental arches.

Quantitative digital subtraction radiography in the assessment of external apical root resorption induced by orthodontic therapy: a retrospective study.

PubMed

Sunku, Raghavendra; Roopesh, R; Kancherla, Pavan; Perumalla, Kiran Kumar; Yudhistar, Palla Venkata; Reddy, V Sridhar

2011-11-01

The objective of this study was to evaluate density changes around the apices of teeth during orthodontic treatment by using digital subtraction radiography to measure the densities around six teeth (maxilla central incisors, lateral incisors, and canines) before and after orthodontic treatment in 36 patients and also assess treatment variables and their coorelation with root resorption. A total of 36 consecutive patient files were selected initially. The selected patients presented with a class I or II relationship and were treated with or without premolar extractions and fixed appliances. Some class II patients were treated additionally with extraoral forces or functional appliances. External apical root resorption (EARR) per tooth in millimeters was calculated and was also expressed as a percentage of the original root length. Image reconstruction and subtraction were performed using the software Regeemy Image Registration and Mosaicing (version 0.2.43-RCB, DPI-INPE, Sao Jose dos Campos, Sao Paulo, Brazil) by a single operator. A region of interest (ROI) was defined in the apical third of the root and density calibration was made in Image J® using enamel (gray value = 255) as reference in the same image. The mean gray values in the ROIs were reflective of the change in the density values between the two images. The root resorption of the tooth and the factors of malocclusion were analyzed with a one-way ANOVA. An independent t-test was performed to compare the mean amount of resorption between male and female, between extraction and nonextraction cases. The density changes after orthodontic treatment were analyzed using the Wilcoxon signedrank test. In addition, the density changes in different teeth were analyzed using the Kruskal-Wallis test. The cut-off for statistical significance was a p-value of 0.05. All the statistical analyses were carried out using SPSS (version 13.0 for Windows, Chicago, IL, USA). Gender, the age at which treatment was started and Angle's classification was not statistically related with observed root resorption. The mean percentage density reduction as assessed by DSR was greatest in both central incisor: by 27.2 and 25.2% in the upper-right and upper-left central incisors, respectively, followed by the upper-right and upper-left canine teeth (23.5 and 21.0%) and then the upper-right and upper-left lateral incisors (19.1 and 17.4%). Tooth extraction prior to treatment initiation and the duration of orthodontic treatment was positively correlated with the amount of root resorption. DSR is useful for evaluating density changes around teeth during orthodontic treatment. The density around the apices of teeth reduced significantly after the application of orthodontic forces during treatment. Assessment of density changes on treatment radiographs of patients undergoing orthodontic therapy may help in the monitoring of external apical root resorption during course of treatment.

Utterance Detection by Intraoral Acceleration Sensor

NASA Astrophysics Data System (ADS)

Saiki, Tsunemasa; Takizawa, Yukako; Hashizume, Tsutomu; Higuchi, Kohei; Fujita, Takayuki; Maenaka, Kazusuke

In order to establish monitoring systems for home health in elderly people including the prevention of mental illness, we investigated the acceleration of teeth in utterance on the assumption that an acceleration sensor can be implanted into an artificial denture in the near future. In the experiment, an acceleration sensor was fixed in front of the central incisors on the lower jaw by using a denture adhesive, and female and male subjects spoke five Japanese vowels. We then measured the teeth accelerations in three (front-to-back, right-to-left and top-to-bottom) axes and conducted frequency analyses. The result showed that high power spectral densities of the teeth accelerations were observed at a low frequency range of 2-10Hz (both the female and the male) and at a high frequency range of 200-300Hz (the female) or 100-150 Hz (the male). The low and high frequency components indicate movements of the lower jaw and voice sounds by bone conduction, respectively. Especially in the top-to-bottom axis of the central incisor, the frequency component appeared to be significant. Therefore, we found that utterance can be efficiently detected using the acceleration in this axis. We also found that three conditions of normal speech, lip synchronizing and humming can be recognized by using frequency analysis of the acceleration in the top-to-bottom axis of the central incisor.

Modelling the Deformation Front of a Fold-Thrust Belt: the Effect of an Upper Detachment Horizon

NASA Astrophysics Data System (ADS)

Burberry, C. M.; Koyi, H.; Nilfouroushan, F.; Cosgrove, J. W.

2008-12-01

Structures found at the deformation fronts of fold-thrust belts are variable in type, geometry and spatial organisation, as can be demonstrated from comparisons between structures in the Zagros Fold-Thrust Belt, Iran and the Sawtooth Range, Montana. A range of influencing factors has been suggested to account for this variation, including the mechanical properties and distribution of any detachment horizons within the cover rock succession. A series of analogue models was designed to test this hypothesis, under conditions scaled to represent the Sawtooth Range, Montana. A brittle sand pack, containing an upper ductile layer with variable geometry, was shortened above a ductile base and the evolution of the deformation front was monitored throughout the deformation using a high-accuracy laser scanner. In none of the experiments did the upper detachment horizon cover the entire model. In experiments where it pinched out perpendicular to the shortening direction, a triangle zone was formed when the deformation front reached the pinch out. This situation is analogous to the Teton Canyon region structures in the Sawtooth Range, Montana, where the Cretaceous Colorado Shale unit pinches out at the deformation front, favouring the development of a triangle zone in this region. When the pinch out was oblique to the shortening direction, a more complex series of structures was formed. However, when shortening stopped before the detachment pinch out was reached, the deformation front structures were foreland-propagating and no triangle zone was observed. This situation is analogous to foreland-propagating thrust structures developed at the deformation front in the Swift Dam region of the Sawtooth Range, Montana and to the development of fault-bend folds at the deformation front of the Zagros Fold-Thrust Belt, Iran. We suggest that the presence of a suitable intermediate detachment horizon within a sediment pile can be invoked as a valid explanation for the development of varied deformation front structures in fold-thrust belts. Specifically, the spatial extent of the upper detachment horizon with respect to the spatial extent of the deformed region is a key influence on the development of deformation front structures. However, we acknowledge that factors such as basement structure and variable sedimentation within the foreland basin may also be key influences on deformation front structures in other fold-thrust belts.

Fronts and intrusions in the upper Deep Polar Water of the Eurasian and Makarov basins

NASA Astrophysics Data System (ADS)

Kuzmina, Natalia; Rudels, Bert; Zhurbas, Natalia; Lyzhkov, Dmitry

2013-04-01

CTD data obtained in the Arctic Basin are analyzed to describe structural features of intrusive layers and fronts encountered in the upper Deep Polar Water. This work is an extension of Arctic intrusions studies by Rudels et al. (1999) and Kuzmina et al. (2011). Numerous examples of fronts and intrusions observed in a deep layer (depth range of 600-1300 m) in the Eurasian and Makarov basins where salinity is increasing, and temperature is decreasing with depth (stable-stable thermohaline stratification), are described. The data are used to estimate hydrological parameters capable of determining different types of fronts and characterizing intrusive layers depending on the front structure. Coherence of intrusive layers is shown to get broken with the change of front structure. An evidence is found that enhanced turbulent mixing above local bottom elevations can prevent from intrusive layering. A linear stability model description of the observed intrusions is developed based on the Merryfield's (2000) assumption that interleaving is caused by differential mixing. Theoretical analysis is focused on prediction of the slopes of unstable modes at baroclinic and thermohaline fronts. Apparent vertical diffusivity due to turbulent mixing at baroclinic and thermohaline fronts is estimated on the basis of comparison of observed intrusion slopes with modeled slopes of the most unstable modes. Apparent lateral diffusivity is estimated too, based on Joyce (1980) approach. These estimates show that intrusive instability of fronts caused by differential mixing can result in sizable values of apparent lateral heat diffusivity in the deep Arctic layer that are quite comparable with those of the upper and intermediate Arctic layers (Walsh, Carmack, 2003; Kuzmina et al., 2011).

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

PubMed

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

2005-01-01

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

Nonsurgical Management of a Periapical Cyst: A Case Report

PubMed Central

Dandotikar, Deepakraj; Peddi, Ravigna; Lakhani, Bharvi; Lata, Kamini; Mathur, Aditi; Chowdary, Uday Kumar

2013-01-01

Large periapical lesions, regardless of whether they are granulomas, abscesses or cysts, are primarily caused by root canal infection. Thus the treatment protocol should be elimination of etiological factors in the root canal system rather than their product, apical true cyst. A 10 year old female patient reported to the Department of Pedodontics and Preventive Dentistry, Dr R Ahmed Dental College & Hospital, Kolkata, with the chief complaint of pain and swelling in relation to upper front fractured teeth. Clinical and radiological findings were suggestive of periapical radicular cyst. Non-surgical endodontic therapy was performed using 1% sodium hypochlorite solution irrigant and Calcium hydroxide intra canal medicament. A 12 months follow-up radiographic examination revealed progressive involution of periapical radiolucency without any clinical symptoms. Periapical cysts respond favorably to non-surgical endodontic treatment and should be considered as primary treatment modality. How to cite this article: Dandotikar D, Peddi R, Lakhani B, Lata K, Mathur A, Chowdary U K. Nonsurgical Management of a Periapical Cyst: A Case Report. J Int Oral Health 2013; 5(3):79-84. PMID:24155607

Nonsurgical management of a periapical cyst: a case report.

PubMed

Dandotikar, Deepakraj; Peddi, Ravigna; Lakhani, Bharvi; Lata, Kamini; Mathur, Aditi; Chowdary, Uday Kumar

2013-06-01

Large periapical lesions, regardless of whether they are granulomas, abscesses or cysts, are primarily caused by root canal infection. Thus the treatment protocol should be elimination of etiological factors in the root canal system rather than their product, apical true cyst. A 10 year old female patient reported to the Department of Pedodontics and Preventive Dentistry, Dr R Ahmed Dental College & Hospital, Kolkata, with the chief complaint of pain and swelling in relation to upper front fractured teeth. Clinical and radiological findings were suggestive of periapical radicular cyst. Non-surgical endodontic therapy was performed using 1% sodium hypochlorite solution irrigant and Calcium hydroxide intra canal medicament. A 12 months follow-up radiographic examination revealed progressive involution of periapical radiolucency without any clinical symptoms. Periapical cysts respond favorably to non-surgical endodontic treatment and should be considered as primary treatment modality. How to cite this article: Dandotikar D, Peddi R, Lakhani B, Lata K, Mathur A, Chowdary U K. Nonsurgical Management of a Periapical Cyst: A Case Report. J Int Oral Health 2013; 5(3):79-84.

Surgical management of impacted incisors in associate with supernumerary teeth: a combine case report of spontaneous eruption and orthodontic extrusion.

PubMed

Das, D; Misra, J

2012-01-01

Maxillary permanent incisors impaction is not a frequent case in dental practice, but its treatment is challenging because of its importance to facial esthetics. Supernumerary teeth are the main cause of impaction of upper incisors. Supernumerary teeth when present can cause both esthetic and pathologic problems. Early detection of such teeth is most important if complications are to be avoided. In this reported case, the orthopantamogram of a 9-year-old boy revealed two impacted supernumerary teeth in the maxillary anterior region, which was interfering with the eruption of the permanent central incisors. The impacted supernumerary teeth were surgically removed, 11 was repositioned in the arch as it was situated very high in the arch, close to the nasal floor. Twenty-one erupted spontaneously but orthodontic force was applied over 11 to bring it into the occlusion and alignment was achieved with 0.014 mm NiTi wire.

Sidewall crystallization and saturation front formation in silicic magma chambers

NASA Astrophysics Data System (ADS)

Lake, E. T.

2012-12-01

The cooling and crystallization style of silicic magma bodies in the upper crust falls on a continuum between whole-chamber processes of convection, crystal settling, and cumulate formation and interface driven processes of conduction and crystallization front migration. In the former case, volatile saturation occurs uniformly chamber wide, in the latter volatile saturation occurs along an inward propagating front. Ambient thermal gradient primarily controls the propagation rate; warm (> 30 °C / km) geothermal gradients promote 1000m+ thick crystal mush zones but slow crystallization front propagation. Cold geothermal gradients support the opposite. Magma chamber geometry plays a second order role in controlling propagation rates; bodies with high surface to magma ratio and large Earth's surface parallel faces exhibit more rapid propagation and smaller mush zones. Crystallization front propagation occurs at speeds of up to 6 cm/year (rhyolitic magma, thin sill geometry, 10 °C / km geotherm), far faster than diffusion of volatiles in magma and faster than bubbles can nucleate and ascend under certain conditions. Saturation front propagation is fixed by pressure and magma crystal content; above certain modest initial water contents (4.4 wt% in a dacite) mobile magma above 10 km depth always contains a saturation front. Saturation fronts propagate down from the magma chamber roof at lower water contents (3.3 wt% in a dacite at 5 km depth), creating an upper saturated interface for most common (4 - 6 wt%) magma water contents. This upper interface promotes the production of a fluid pocket underneath the apex of the magma chamber. Magma de-densification by bubble nucleation promotes convection and homogenization in dacitic systems. If the fluid pocket grew rapidly without draining, hydro-fracturing and eruption would result. The combination of fluid escape pathways and metal scavenging would generate economic vein or porphyry deposits.

White-spot lesions during multibracket appliance treatment: A challenge for clinical excellence.

PubMed

Enaia, Mahmoud; Bock, Niko; Ruf, Sabine

2011-07-01

White-spot lesions (WSL) are one of the most undesired side effects of multibracket appliance treatment (MB). The aim of this study was to investigate the incidence and further course of WSL during and after MB. Four hundred patients (168 boys, 232 girls) meeting the inclusion criteria--all maxillary front teeth fully erupted and visible before treatment, no fillings or structural abnormalities, MB duration of at least 1 year, and retention period of at least 1 year--were selected. The patients' average age was 13.7 years (SD, 3.5), and the average MB time was 1.9 years (SD, 3.6). All patients received standardized general prophylactic instructions. A modification of the WSL index was used to evaluate the 4 maxillary front teeth on introral photos before and after treatment, and after retention. Before treatment, 32.3% of the patients had WSL. After MB, 73.5% of the patients presented WSL. The incidence of WSL during MB was 60.9% of the patients. After treatment, most patients (63.3%) had mild lesions, but the remaining were affected severely with (26.9%) and without (9.9%) cavitations. Only 26% of the patients were free of WSL all the time. After the retention phase, most (57.1%) of the WSL patients after treatment showed improvement, 26% remained unchanged, and 16.7% deteriorated. Male WSL patients tended to show more severe WSL than did the girls. There was a tendency for increased WSL development during the adolescent years compared with the preadolescent and postadolescent age groups. With only standardized general prophylactic measures, new WSL developing on the maxillary front teeth during MB remain a frequent undesired side effect, affecting 60.9% of patients and counteracting our efforts for clinical excellence. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Herbst appliance with skeletal anchorage versus dental anchorage in adolescents with Class II malocclusion: study protocol for a randomised controlled trial.

PubMed

Batista, Klaus Barretto Dos Santos Lopes; Lima, Tatiana; Palomares, Nathália; Carvalho, Felipe de Assis; Quintão, Cátia; Miguel, José Augusto Mendes; Lin, Yin-Ling; Su, Ting-Li; O'Brien, Kevin

2017-11-25

The Herbst appliance is an orthodontic appliance that is used for the correction of class II malocclusion with skeletal discrepancies. Research has shown that this is effective. However, a potential harm is excessive protrusion of the lower front teeth. This is associated with gingival recession, loss of tooth support, and root resorption. This trial evaluates a method of reducing this problem. The study is a single-center, randomised, assessor-blinded, superiority clinical trial with parallel 1:1 allocation. Male and female young people (10-14 years old) with prominent front teeth (class II, division 1) will be treated in one orthodontic clinic. Group 1 will be treated with the conventional Herbst appliance with dental anchorage and group 2 with the Herbst appliance with indirect skeletal anchorage for 12 months. The primary objective will be to compare the proclination of the lower incisors between the Herbst appliance with dental anchorage and skeletal anchorage. Secondary objectives will be to evaluate the changes occurring between the groups in the mandible, maxilla, lower and upper molars, and in gingival recession and root resorption at the end of the treatment. Additionally, the young patient's experience using the appliances will be assessed. The primary outcome measure will be the amount of lower incisor proclination at the end of treatment. This will be assessed by cone-beam computed tomography (CBCT) superimposition. Secondary outcome measures will be the changes in the mandible, maxilla, lower and upper molars at the end of treatment assessed by tomography superimposition and the young patient's experience using the appliances assessed by self-reported questionnaires and semi-structured interviews. The randomisation method will be blocked randomisation, using software to generate a randomised list. The allocation concealment will be done in opaque envelopes numbered from 1 to 40 containing the treatment modality. The randomisation will be implemented by the secretary of the Department of Orthodontics of Rio de Janeiro State University before the beginning of the study. The patients and the orthodontists who will treat the patients cannot be blinded, as they will know the type of appliance used. The technician who will take the CBCT image and the data analyst will be blinded to patients' group allocation. If this new intervention is effective, the findings can change orthodontic practice and may also be relevant to other forms of treatment in which appliances are fixed to the bones of the jaws. However, if the bone anchoring is not effective, the trial will provide much needed information on the use of this comparatively new development. ClinicalTrials.gov, protocol ID: NCT0241812 . Registered on 26 March 2015.

Evidence from tooth surface morphology for a posterior maxillary origin of the proteroglyph gang

USGS Publications Warehouse

Jackson, K.; Fritts, T.H.

1995-01-01

Although the front-fanged venom delivery system of the Elapidae is believed to be derived from an aglyphous or opisthoglyphous colubroid ancestor, opinion is divided as to the end of the maxilla on which the proteroglyph fang originated. This study was undertaken to determine whether the evolutionary precursor of the proteroglyph fang was (a) a grooved posterior fang which migrated anteriorly, or (b) an enlarged anterior tooth which secondarily developed a groove for the conduction of venom. The surface morphology of the maxillary teeth of colubrid genera was examined using scanning electron microscopy. Ridges present on the lingual and labial surfaces of anterior maxillary teeth and on the anterior and posterior surfaces of posterior maxillary teeth were identified as morphological markers of potential value in distinguishing the anterior and posterior maxillary teeth of colubrid snakes, and in determining the origin of the proteroglyph fang. Patterns of ridges on the surfaces of elapid fangs examined were found to be consistent with the hypothesis that the evolutionary precursor of the proteroglyph fang was an opisthoglyph fang which migrated anteriorly.

The Nature of The Propagation of Sea Breeze Fronts in Central California

DTIC Science & Technology

1990-09-01

propagation vector % ith stations in the southern portion of Monterey Bay shows that the front is curved on the mesoscale. 20 Distribution Availabilit of...solar radiation warms the land more than the adjacent water . The resulting temperature contrast produces a slight variation in pressure. The isobaric...surfaces bend upward over the land, producing an upper-level high. The upper-level air flows seaward increasing the surface pressure over the water . The

Morphologic analysis of third-molar maturity by digital orthopantomographic assessment.

PubMed

Introna, Francesco; Santoro, Valeria; De Donno, Antonio; Belviso, Maura

2008-03-01

Accurate timing of the eruption of first and permanent teeth is an important parameter in forensic odontology to establish the age of dead or live individuals. Determination of adulthood may determine, for example, whether an individual convicted of a crime is sentenced as an adult and incarcerated in a state penal institution or as a juvenile and sent to a juvenile camp. At present, there is a large immigrant population in Italy, and young foreign criminals sometimes have false passports bearing a later birth date, with the aim of evading punishment. In such circumstances, age determination is becoming a significant forensic issue.Late in adolescence, after formation of the premolars and canines, only the third molars continue to develop. According to several studies, although the third molars are the most variable teeth in the dentition, they remain the most reliable biologic indicator available for estimation of age during the middle teens and early twenties.In this study, the authors test the possibilities offered by orthopantomography executed by means of digital technology, with the aim of exploiting the advantages of the computerized digital technique compared with the conventional technique, to determine adult age on the basis of root development of the third molar.Digital radiography is simple to use, quick, and effective, allowing superimposition and enlargement; the images can be electronically stored and transported. In comparison with traditional orthopantomography, the digital technique features greater diagnostic accuracy of some anatomic structures: upper and lower front teeth, root apexes, floor of the nasal fossa and maxillary sinus, nasal septum, mandibular condylus. Moreover, digital orthopantomography suffers less from artifacts.The digital orthopantomographies of 83 Caucasian subjects (43 females and 40 males) aged between 16 and 22 years were analyzed in standard conditions, assessing the degree of maturation of the upper and lower third molars. A standardized computer procedure was used to acquire the x-ray images, recording 3 per plate: the overall orthopantomography and 2 enlargements of optical type of the left and right sides, to reveal the third molars while maintaining unaltered the image resolution.For the analysis, the authors adopted Demirjian's staging system that classifies development of the third molar in 8 stages (A, B, C, D, E, F, G, H) on the basis of morphologic criteria. This has been statistically proved to feature notable precision and high predictive ability.To assess any sex-related variations in mineralization speed, the series was subdivided by gender. The study demonstrated that such differences are more evident under the age of 18 years.Overall, the observation of 245 third molars showed faster development of the upper than the lower third molars, a prevalence of stages D to G in the age range between 16 and 18 years, and a clear predominance of stage H in individuals over 18 years of age. Finally, an intermediate stage between G and H was demonstrated in subjects aged between 17 and 21 years.

Device for reducing vehicle aerodynamic resistance

DOEpatents

Graham, Sean C.

2006-03-07

A device for reducing vehicle aerodynamic resistance for vehicles having a generally rectangular flat front face comprising a plurality of load bearing struts of a predetermined size attached to the flat front face adjacent the sides and top thereof, a pair of pliable opposing flat sheets having an outside edge portion attached to the flat front face adjacent the sides thereof and an upper edge with a predetermined curve; the opposing flat sheets being bent and attached to the struts to form effective curved airfoil shapes, and a top pliable flat sheet disposed adjacent the top of the flat front face and having predetermined curved side edges, which, when the top sheet is bent and attached to the struts to form an effective curved airfoil shape, mate with the curved upper edges of the opposing sheets to complete the aerodynamic device.

Multiple tooth anomalies in a nonsyndromic patient with class II division 2 malocclusions: A case report and a literature review.

PubMed

Isman, E; Isman, O; Aktan, A M; Ciftci, E; Topcuoglu, T

2015-01-01

Reports in the literature about the craniofacial characteristics of patients with class II division 2 malocclusions show a lot of different patterns accompanied by palatally displaced upper incisors, congenital missing teeth, polydiastema, fusion, germination, tooth impaction, peg-shaped lateral incisors, persistent teeth, hypodontia, persistent deciduous teeth, transpositions, and supernumerary teeth. The following case report focuses on the description of the clinical characteristics observed on a patient with a very unusual conjunction of dental and skeletal anomalies mentioned above, as well as a literature review on the related issues. Extra-intra-oral examinations, radiographic evaluations, orthodontic consultation, and reviewing the literature concluded that this nonsyndromic patient that refused to receive all dental treatment approaches is special with its uniqueness.

Double diffusion in the frontal zones of the Yellow and East China Seas in winter

NASA Astrophysics Data System (ADS)

Oh, K.; Lee, S.

2017-12-01

Where the cold, fresh water of the Yellow Sea (YS) and the warm, salty water of the East China Sea (ECS) meet, northern and southern fronts are formed in the southeastern YS and the northwestern ECS, respectively. Strong thermohaline fronts are formed on the northern front, and a strong thermocline and a temperature reversal phenomenon are represented in this front. To understand the water structure of this thermohaline zone, we examined double diffusion in the frontal zones in February 2003 using hydrographic data. In the northern front, the warm, salty Cheju Warm Current Water (CWCW) moved northwards along the bottom layer and the cold, fresh Yellow Sea Cold Water (YSCW) flowed southward in the upper layer. As a result, strong thermohaline fronts forms in the area where the two water masses met, and the slope was developed downward across the front. In this area, a strong thermocline and temperature reversal structures were present. The cold, fresh Korean Coastal Water (KCW) was also found in the upper layer near the thermocline, and has a low-temperature, low-salinity more than surrounding water. When cold, fresh water is located over warm, salty water, heat diffuses through the interface between the two water masses, and then the diffusive-convection can be expected to occur. On the other hand, when warm, salty water overlays cold, fresh water, heat in the upper layer is preferentially transferred downward, and the salt-fingering occurs. The diffusive-convection occurs predominantly in the northern thermohaline front, where the cold, fresh YSCW is situated above the warm, salty CWCW and has the effect of strengthening stratification, so that the water column maintains a physically stable structure. In addition, this phenomenon seems to play a role in maintaining the reversal structure. The salt-fingering occurs in upper layers of the northern front where the cold, fresh YSCW is located over the most cold, fresh KCW. Near the northern thermo-halocline zone, the salt-fingering occurs simultaneously with the diffusive-convection, because three water masses, YSCW, KCW and CWCW, interact in that area. Therefore, it can be seen that the water structure of the northern frontal zone in winter is influenced mainly by the cold, fresh YSCW, the most cold, fresh KCW, and the warm, salty CWCW.

Middle Pleistocene Hominin Teeth from Longtan Cave, Hexian, China

PubMed Central

Xing, Song; Martinón-Torres, María; Bermúdez de Castro, José María; Zhang, Yingqi; Fan, Xiaoxiao; Zheng, Longting; Huang, Wanbo; Liu, Wu

2014-01-01

Excavations at the Longtan Cave, Hexian, Anhui Province of Eastern China, have yielded several hominin fossils including crania, mandibular fragments, and teeth currently dated to 412±25 ka. While previous studies have focused on the cranial remains, there are no detailed analyses of the dental evidence. In this study, we provide metric and morphological descriptions and comparisons of ten teeth recovered from Hexian, including microcomputed tomography analyses. Our results indicate that the Hexian teeth are metrically and morphologically primitive and overlap with H. ergaster and East Asian Early and mid-Middle Pleistocene hominins in their large dimensions and occlusal complexities. However, the Hexian teeth differ from H. ergaster in features such as conspicuous vertical grooves on the labial/buccal surfaces of the central incisor and the upper premolar, the crown outline shapes of upper and lower molars and the numbers, shapes, and divergences of the roots. Despite their close geological ages, the Hexian teeth are also more primitive than Zhoukoudian specimens, and resemble Sangiran Early Pleistocene teeth. In addition, no typical Neanderthal features have been identified in the Hexian sample. Our study highlights the metrical and morphological primitive status of the Hexian sample in comparison to contemporaneous or even earlier populations of Asia. Based on this finding, we suggest that the primitive-derived gradients of the Asian hominins cannot be satisfactorily fitted along a chronological sequence, suggesting complex evolutionary scenarios with the coexistence and/or survival of different lineages in Eurasia. Hexian could represent the persistence in time of a H. erectus group that would have retained primitive features that were lost in other Asian populations such as Zhoukoudian or Panxian Dadong. Our study expands the metrical and morphological variations known for the East Asian hominins before the mid-Middle Pleistocene and warns about the possibility that the Asian hominin variability may have been taxonomically oversimplified. PMID:25551383

The unmet treatment need of traumatized anterior teeth in selected secondary school children in Ibadan, Nigeria.

PubMed

Ajayi, Mojirade Deborah; Denloye, Obafunke; Abiodun Solanke, Funmilayo I

2010-02-01

Treatment of traumatized anterior teeth is highly desirable to relieve pain, maintain esthetics and to preserve the balance of the anterior part of the mouth; however many may go untreated. The aim of this study was to assess the prevalence of damage to permanent anterior teeth in school adolescents, the average duration of trauma and to ascertain the level of the unmet treatment need. A total of 1532 secondary school children between the ages 12 and 19 years participated in the study. They were randomly selected from public secondary schools in five local government areas in Ibadan using a multistage sampling method. Participants were examined with the aid of mouth mirrors and probes under natural light. Traumatic anterior dental injuries were recorded by the same investigator (DMA) according to WHO classification. One hundred and sixty-five participants sustained injuries to their anterior teeth. Their mean age was 15.47 +/- 2.09 years, with a male to female ratio of 1.5:1. The commonest cause was fall (78.8%) with road traffic accident being the least (1.8%). The tooth most commonly injured is the upper left incisor (48.0%) closely followed by upper right central (43.1%). Enamel fracture was seen in 46.5% and enamel-dentine in 42.6% of the traumatized teeth. Most (79.4%) of the children sustained injury to one tooth only. Of the participants, only 30 (18.2%) had previous dental consultation while only nine (5.5%) consulted the dentist following the trauma; however, none of the teeth had any form of restoration. Average time elapsed between trauma and dental examination was about 3.5 years. Many participants had had injury for about 2 years before dental examination. In conclusion, there is a high unmet treatment need of traumatized anterior teeth in the study population.

[Combined surgical-orthodontic therapy for compound odontoma].

PubMed

Dukić, Walter; Kuna, Tihomir; Lapter-Varga, Marina; Jurić, Hrvoje; Lulić-Dukić, Olga

2007-09-01

Odontogenic tumor is a rare condition in dental medicine that mostly proceeds unrecognized until the occurrence of clinical symptoms such as delayed eruption, or is incidentally detected on routine x-ray examination. The exact cause is not known, however, previous dental trauma and infection have been postulated as the potential factors in the development of odontogenic tumor. The earliest possible operative extirpation of the tumorous growth is recommended to eliminate permanent tooth impaction and to enable normal growth of the teeth. In some cases, corticotomy, including complete removal of the bony coat of the tooth, may be needed to additionally facilitate and precipitate its eruption. Orthodontic therapy is also of great importance in correct alignment of the teeth 'n the dental arch as well as in the management of other anomalies that may be associated with odontogenic tumor. A patient with compound odontoma is presented, along with the course of combined surgical-orthodontic therapy. The patient reported previous intrusion trauma that had occurred at the age of 4 years, which may have been the potential factor in the development of odontoma. In this case, there was a massive odontogenic tumor which had compromised the growth of permanent teeth, and the growth impulse was almost at the end since the patient was 11 years old and the apexes of the upper incisors were partially closed. The first operation included complete removal of the tumorous mass that had interrupted spontaneous eruption of the upper permanent incisors. It did not result in immediate spontaneous tooth eruption, so an additional operation was needed. The objective of the second operative procedure was complete removal of the covering bone over the unerupted upper permanent incisors in order to eliminate the physical barrier to tooth growth and eruption. The objective of fixed orthodontic therapy was full eruption of the partially erupted upper incisors. After 16 months, the upper incisors were regularly located in the dental arch. In this case, orthodontic therapy had another objective, i.e. to ensure rotation of the first upper premolar, to provide space for the upper permanent canine eruption and to establish regular intercuspidation after upper second premolar hypodontia. In colclusion, combined operative and orthodontic therapy can be recommended irrespective of the stage of the impacted tooth development because any treatment to precipitate tooth eruption has favorable effects. Impacted teeth should always be provided all treatment options for faster eruption, as demonstrated in our case where a good clinical result was achieved within 2.5 years. The role of regular clinical and x-ray controls for assessment of the impacted tooth eruption should also be emphasized.

A new species of Muraenichthys (Anguilliformes: Ophichthidae) from the Indo-Pacific, with revised generic diagnosis.

PubMed

Hibino, Yusuke; Kimura, Seishi

2015-12-24

A new worm eel (Ophichthidae, Myrophinae), Muraenichthys velinasalis, is described based on five specimens (97.9-281.0 mm of total length) collected from Taiwan, Philippines, northeastern Australia, Vanuatu, and Sri Lanka. Muranichthys velinasalis is most similar to M. philippinensis and M. schultzei in the position of the dorsal-fin origin behind a vertical through mid-anus, but can be easily distinguished from the latter two species by the condition of the posterior nostril, unique character of M. velinasalis within Muraenichthys, and by the shape of the teeth on the innermost row of the upper jaw (relatively robust and slightly pointed vs. slender and pointed), arrangement of upper-jaw teeth (irregularly biserial anteriorly and uniserial posteriorly vs. completely uniserial in M. philippinensis, biserial or triserial in M. schultzei), and its more numerous or fewer preanal and total vertebrae (44-51 vs. 59-60 in M. philippinensis, 42-47 in M. schultzei; 136-139 vs. 128-130 in M. philippinensis, 119-128 in M. schultzei). The genus Muraenichthys is re-defined based on all currently valid species by the following combination of characters: eyes located anterior to mid-jaw; inner hole of posterior nostril above upper lip, and outer hole usually outside of mouth, with a prominent but short projected flap anteriorly; a single pore between anterior and posterior nostrils; three preopercular pores; teeth on jaws, vomer, and intermaxillary area; tooth shape variable, blunt to pointed but not distinctly recurved and tooth length equal or less than a half of eye diameter; teeth on jaws and vomer arranged in one to five rows; gill opening constricted, its height<170% of eye diameter; pectoral fins absent.

Effectiveness of a new non-hydrogen peroxide bleaching agent after single use - a double-blind placebo-controlled short-term study.

PubMed

Bizhang, Mozhgan; Domin, Julia; Danesh, Gholamreza; Zimmer, Stefan

2017-01-01

Tooth whitening represents perhaps the most common aesthetic procedure in dentistry worldwide. The efficacy of bleaching depends on three aspects: bleaching agent, bleaching method, and tooth color. This in vivo study aimed to examine whitening effects on frontal teeth of the upper and lower jaws using an over-the-counter (OTC) non-hydrogen peroxide bleaching agent in comparison to a placebo after one single use. Forty subjects (25 female; 15 male) participated in this double-blind randomized placebo-controlled trial. The subjects were randomly allocated to two groups (n=20). The test group received the OTC product (iWhite Instant) and the placebo group received an identically composed product except for the active agents. Each subject was treated with a prefilled tray containing iWhite Instant or the placebo for 20 minutes. The tooth shade of the front teeth (upper and lower jaws) was assessed before (E_0), immediately after (E_1) and 24 h after treatment (E_2), using a shade guide (VITA classical). Statistical testing was accomplished using the Mann-Whitney U test (p<0.001). The dropout rate was 0%. There were no significant differences at E_0 between placebo and test groups regarding the tooth color. Differences in tooth color changes immediately after (ΔE1_0) and 24 h after treatment (ΔE2_0) were calculated for both groups. The mean values (standard deviations) of tooth color changes for ΔE1_0 were 2.26 (0.92) in the test group and 0.01 (0.21) in the placebo group. The color changes for ΔE2_0 showed mean values of 2.15 (1.10) in the test group and 0.07 (0.35) in the placebo group. For ΔE1_0 and ΔE2_0 significant differences were found between the groups. In this short-term study, the results showed that a non-hydrogen peroxide bleaching agent has significant whitening effects immediately and 24 h after a single-use treatment.

The chronology and sequence of eruption of human permanent teeth in Northern Ireland.

PubMed

Kochhar, R; Richardson, A

1998-12-01

To ascertain the average and range of ages and sequence of eruption of human permanent teeth, taking into account the effect of premature loss of primary antecedents. Longitudinal study. Caucasian subjects in Northern Ireland. Study casts at 6-monthly intervals from age 5 to 15 years of 276 children (146 males and 130 females) enrolled in the Belfast Growth Study. The mean and range of ages of eruption of each individual tooth were computed. Comparisons were made between the mean ages of eruption with and without premature loss of primary antecedents, between upper and lower arches, between right and left sides and between males and females. The sequence of eruption was also investigated. The means and ranges of eruption ages are reported. Premature loss of primary antecedents delayed eruption of permanent successors except for the upper premolars which were accelerated. The differences relating to the upper first premolar and lower canine were not statistically significant. Each lower tooth erupted before its upper counterpart except for the premolars. There was no significant difference in age of eruption between right and left sides. Females tended to erupt teeth before males with the exception of the second molars in both arches; however, the only differences to reach statistical significance related to upper and lower canines and upper lateral incisors. The most frequent orders of eruption were unique to the subject. These occurred in 22% of upper and 33% of lower arches. The classic sequences: first molar-central incisor-lateral incisor-first premolar-canine-second premolar-second molar (M1-I1-I2-PM1-C-PM2-M2) in the upper arch and I1-M1-I2-C-PM1-PM2-M2 in the lower arch occurred in only 16% of upper arches and 13% of lower arches. Males adhered to the textbook sequence (20% upper, 17% lower) more than females (12% upper, 8% lower). In the upper arch of females, the order M1-I1-I2-PM1-PM2-C-M2 in 10% of subjects was almost as frequent as the classic sequence. The ages, ranges and orders of eruption found in this study are more reliable than many which are frequently quoted on account of its longitudinal nature and the fact that the effect of premature loss of primary antecedents is taken into account. The exclusively Caucasian sample makes the data quite precise but limits applicability to patients of this ethnic origin.

Esthetic Rehabilitation through Crown Lengthening Surgery and Conservative CAD/CAM Veneers: A Multidisciplinary Case Report

PubMed Central

Soares, Fernando Peixoto; Gallo, Mauricio

2016-01-01

This case report describes a successful multidisciplinary approach used to improve the smile esthetics of a patient presenting with excessive gingival display, asymmetric gingival margins, and small upper anterior teeth and lower anterior teeth. The treatment combined esthetic crown lengthening, dental bleaching, and restorative dentistry using CAD/CAM veneer. The 6-month follow-up examination confirmed the stability of the modification and absence of adverse effects. PMID:27668099

Submesoscale-selective compensation of fronts in a salinity-stratified ocean.

PubMed

Spiro Jaeger, Gualtiero; Mahadevan, Amala

2018-02-01

Salinity, rather than temperature, is the leading influence on density in some regions of the world's upper oceans. In the Bay of Bengal, heavy monsoonal rains and runoff generate strong salinity gradients that define density fronts and stratification in the upper ~50 m. Ship-based observations made in winter reveal that fronts exist over a wide range of length scales, but at O(1)-km scales, horizontal salinity gradients are compensated by temperature to alleviate about half the cross-front density gradient. Using a process study ocean model, we show that scale-selective compensation occurs because of surface cooling. Submesoscale instabilities cause density fronts to slump, enhancing stratification along-front. Specifically for salinity fronts, the surface mixed layer (SML) shoals on the less saline side, correlating sea surface salinity (SSS) with SML depth at O(1)-km scales. When losing heat to the atmosphere, the shallower and less saline SML experiences a larger drop in temperature compared to the adjacent deeper SML on the salty side of the front, thus correlating sea surface temperature (SST) with SSS at the submesoscale. This compensation of submesoscale fronts can diminish their strength and thwart the forward cascade of energy to smaller scales. During winter, salinity fronts that are dynamically submesoscale experience larger temperature drops, appearing in satellite-derived SST as cold filaments. In freshwater-influenced regions, cold filaments can mark surface-trapped layers insulated from deeper nutrient-rich waters, unlike in other regions, where they indicate upwelling of nutrient-rich water and enhanced surface biological productivity.

Multivariate analyses reveal a new assemblage of diverse and small archosauriforms (Reptilia, Diapsida) from the Upper Triassic of India

NASA Astrophysics Data System (ADS)

Shafi Bhat, Mohd; Ray, Sanghamitra; Mohan Datta, Pradipendra

2017-04-01

The study is based on a large collection of vertebrate microfossils collected from the Upper Triassic Tiki Formation of the Rewa Gondwana basin of India, which is a mud-dominated fluvial succession. About 8600 kg of mudrocks from the Tiki Formation were screen washed to yield 1865 vertebrate microfossils, of which 67% are isolated teeth. Of these, there are about 450 well-preserved teeth, which are leaf-shaped, slightly recurved and have subtriangular crowns with expanded and asymmetric bases, and distinct denticles both on the posterior or anterior carinae. The morphology of these teeth suggests that these belong to Archosauriformes (Heckert, 2004; Irmis et al., 2007). Since the teeth were found isolated, without being associated with any other skeletal elements, it is not possible to ascertain their taxonomic position up to the generic and species level. However, based on their distinct dental attributes, twelve morphotypes are identified, of which five show similarity with the teeth of the basal saurischian dinosaurs. Principal Component and Canonical Variate analyses (PCA and CVA) are performed on these isolated teeth to evaluate the differentiation of the specimens based on the variance of their variables and to assess the consistency of identification by qualitative and quantitative methods (Hammer and Harper, 2006). PCA and CVA are applied to the variance-covariance matrix of the logarithmically transformed variables, the latter including six measured dimensions characterizing the different crown proportions. Since the first three principal components (PCs) account for more than 98% of the total variance, PC4 is discarded. Principal component scores are plotted on PC 1 and PC 2, and PC 2 and PC 3 to show the scatter of the archosauriform teeth examined. Although distinct clustering of specimens belonging to the different morphotypes is seen, there is considerable overlapping as represented by the convex hull polygons. The quantitative analyses show that many of the teeth collected from the Tiki Formation are similar to that of other known Late Triassic archosauriforms such as Protecovasaurus, Revueltosaurus, Pekinosaurus and Crosbysaurus Although more analyses are required for precise taxonomic identification, the current study highlights a large array of Late Triassic archosauriforms from India, which so far remained unknown. References: Hammer, O., Harper, D.A.T. 2006. Paleontological data analysis. Blackwell Publishing, Ltd., Malden, USA. Heckert, A.B. 2004. Late Triassic microvertebrates from the Upper Triassic Chinle Group (Otischalkian-Adamanian: Carnian), southwestern U.S.A.: New Mexico Museum of Natural History and Science Bulletin 27:1-170. Irmis, R.B., Parker, W.G., Nesbitt, S.J., Liu, J. 2007. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19: 3-22.

Evaluation of maxillary anterior teeth and their relation to the golden proportion in Malaysian population.

PubMed

Al-Marzok, Maan Ibrahim; Majeed, Kais Raad Abdul; Ibrahim, Ibrahim Khalil

2013-01-24

The maxillary anterior teeth are important in achieving pleasing dental aesthetics. Various methods are used to measure the size and form of them, including the golden proportion between their perceived widths, and the width-to-height ratio, referred to as the golden standard. The purpose of this study was conducted to evaluate whether consistent relationships exist between tooth width and height of the clinical crown dimensions; and to investigate the occurrence of the golden proportion of the maxillary anterior teeth. Dental casts of the maxillary arches were made in this cross-sectional study from MAHSA University College students who met the inclusion criteria. The 49 participants represented the Malaysian population main ethnics. The dimensions of the anterior teeth and the perceived width of anterior teeth viewed from front were measured using a digital caliper. Comparison of the perceived width ratio of lateral to central incisor and canine to lateral incisor with the golden proportion of 0.618 revealed there were a significant statistical difference (p < 0.05). The statistical difference was significant for the width-to-height ratio of central incisors to the golden standard of 80%. There was no significant difference in the comparison among ethnic groups for the golden proportion and the golden standard. The golden proportion was not found to exist between the perceived widths of maxillary anterior teeth. No golden standard were detected for the width-to-height proportions of maxillary incisors. Specific population characteristics and perception of beauty must be considered. However, ethnicity has no association with the proportions of maxillary anterior teeth.

3D variations in human crown dentin tubule orientation: a phase-contrast microtomography study.

PubMed

Zaslansky, Paul; Zabler, Simon; Fratzl, Peter

2010-01-01

Tubules dominate the microstructure of dentin, and in crowns of human teeth they are surrounded by thick mineralized peritubular cuffs of high stiffness. Here we examine the three-dimensional (3D) arrangement of tubules in relation to enamel on the buccal and lingual aspects of intact premolars and molars. Specifically we investigate the angular orientation of tubules relative to the plane of the junction of dentin with enamel (DEJ) by means of wet, non-destructive and high-resolution phase-contrast (coherent) tomography. Enamel capped dentin samples (n=16), cut from the buccal and lingual surfaces of upper and lower premolar and molar teeth, were imaged in water by high-resolution synchrotron-based phase-contrast X-ray radiography. Reconstructed 3D virtual images were co-aligned with respect to the DEJ plane. The average tubule orientation was determined at increasing distances from the DEJ, based on integrated projections onto orthogonal virtual planes. The angle and curl of the tubules were determined every 100 microm to a depth of 1.4mm beneath the DEJ. Most tubules do not extend at right angles from the DEJ. Even when they do, tubules always change their orientations substantially within the first half-millimeter zone beneath the DEJ, both on the buccal and lingual aspects of premolar and molar teeth. Tubules also tend to curl and twist within this zone. Student t-tests indicate that lower teeth seem to have greater tilts in the tubule orientations relative to the DEJ normal with an average angle of 42 degrees (+/-2.0 degrees), whereas upper teeth exhibit a smaller change of orientation, with an average of 32 degrees (+/-2.1 degrees). Tubules are a central characteristic of dentin, with important implications on how it is arranged and what the properties are. Knowing about the path that tubules follow is important for various reasons, ranging form improving control over restorative procedures to understanding or simulating the mechanical properties of teeth. At increasing depths of dentin beneath enamel, tubules are significantly tilted relative to the DEJ norm, which may be important to understand clinical challenges such as sensitivity, effectiveness of bonding techniques or prediction of possible paths for bacterial invasion. Our data show dissimilar average tubule angles of upper versus lower teeth with respect to the DEJ which presumably contributes to different shear responses of the tissue under function. The degree to which this may warrant improved restoratives or new adhesive techniques to enhance adhesive restorations merits further investigation.

How well can fishes prey on zebra mussels in eastern North America?

USGS Publications Warehouse

French, John R. P.

1993-01-01

Literature on mollusk-eating fishes was reviewed to determine the potential for different species of fish to control zebra mussels in eastern North America. At least six species are potential predators of zebra mussels because they possess (1) both upper and lower pharyngeal teeth or (2) lower pharyngeal teeth and chewing pads located on the dorsal roof for crushing mollusk shells. Freshwater drum (Aplodinotus grunniens) and two centrarchids, redear sunfish (Lepomis microlophus) and pumpkinseed (L. gibbosus), possess both upper and lower pharyngeal teeth and are likely to consume more zebra mussels than fishes with only lower pharyngeal teeth. Only two catostomid species, copper and river redhorses (Moxostoma hubbsi and M. carinatum), have chewing pads that enable them to crush mollusks. The exotic omnivorous common carp (Cyprinus carpio), possessing lower teeth and a chewing pad, may prey on zebra mussels when aquatic insect larvae, its preferred food, become rare. Managing populations of drum, sunfishes and redhorses to reduce exploitation of large individuals and improve their habitats are suggested as means to intensify biological control of zebra mussels in eastern North America. Other Eurasian molluscivores, the roach (Rutilus rutilus) and the black carp (Mylopharyngodon piceus) should not be introduced into North America because research has shown repeatedly that an introduced biological controller usually does not forage for unwanted pests or reside only in preferred habitats of pests. Drum, sunfishes and redhorses should be preferred over these exotics as biological controllers of zebra mussels in North America because these native fishes will likely occupy newly established habitats of zebra mussels.

Rupture propagation behavior and the largest possible earthquake induced by fluid injection into deep reservoirs

NASA Astrophysics Data System (ADS)

Gischig, Valentin S.

2015-09-01

Earthquakes caused by fluid injection into deep underground reservoirs constitute an increasingly recognized risk to populations and infrastructure. Quantitative assessment of induced seismic hazard, however, requires estimating the maximum possible magnitude earthquake that may be induced during fluid injection. Here I seek constraints on an upper limit for the largest possible earthquake using source-physics simulations that consider rate-and-state friction and hydromechanical interaction along a straight homogeneous fault. Depending on the orientation of the pressurized fault in the ambient stress field, different rupture behaviors can occur: (1) uncontrolled rupture-front propagation beyond the pressure front or (2) rupture-front propagation arresting at the pressure front. In the first case, fault properties determine the earthquake magnitude, and the upper magnitude limit may be similar to natural earthquakes. In the second case, the maximum magnitude can be controlled by carefully designing and monitoring injection and thus restricting the pressurized fault area.

[Simultaneous intrusion and retraction of the anterior teeth using a three-piece base arch].

PubMed

Liu, D; Bai, D; Wang, C; Sun, W; Guo, J; Xi, R

2000-06-01

To evaluate the effects of the three-piece base arch on overbite correction of Class II malocclusion. 20 patients with high angle, flared incisors were treated using a three-piece base arch appliance. The intrusion force of four upper incisors was adjusted to approximately 50 g. The line of force action was 2 mm distally to the resistant center(RC) and the retraction force was 20 g, the right and left posterior segments were joined by a palatal bar. Cephalograms were taken before treatment (T1) and six months after treatment (T2). The upper molars moved mesially 0.60 +/- 0.35 mm and the distance of the vertical extrusion was 0.80 +/- 0.52 mm. The distances of the upper central incisor retraction and intrusion were -4.20 +/- 2.12 mm and 3.10 +/- 0.54 mm respectively. The RC of the central incisor retracted -4.12 +/- 1.96 mm and intruded 3.20 +/- 0.66 mm. The axial inclination of the upper incisor-palatal plane changed from 123.21 degrees +/- 4.26 degrees to 116.00 degrees +/- 3.96 degrees. The three-piece segmented approach can effectively intrude and retract the upper anterior teeth for flared incisors and deep overbite.

A study of formation and development of one kind of cyclone on the mei-yu (Baiu) front

NASA Astrophysics Data System (ADS)

Zhang, Feng; Zhao, Sixiong

2004-10-01

The paper presents one diagnosis of baroclinity and the coupling of jets during the developing process of a cyclone that occurred on the mei-yu (Baiu) front around the end of the second stage of the mei-yu (Baiu) in 1998. Results have shown that: (1) The advantageous changes of upper-level large-scale circulation caused the appearance and maintenance of the coupling between the upper-level jet (ULJ) and lower-level jet (LLJ) over the cyclone’s area. The coupling of jets in this case possesses some different characteristics from previous cases. Moreover, the coupling between the ULJ and LLJ caused the intensification of both lower-level convergence and upper-level divergence, which was favorable for the development of this cyclone. (2) From the analysis of the voricity budget, the role of lower-level convergence in the development of the cyclone was emphasized. Divergent wind in the lower troposphere was a direct contributor to the development of the cyclone. (3) During the development of the cyclone, cold air and warm air were active over the cyclone’s domain. Although this cyclone occurred at the mei-yu (Baiu) front, its development assumed baroclinity to a certain extent, which was just the main difference between this kind of cyclone and the first kind of low which is usually barotropic (or quasi-barotropic). (4) In recent years, studies on mei-yu front lows have paid more attention to the lower troposphere. In this paper, the analysis of the energy budget further supports this point: the certain effect of baroclinity forcing in the upper troposphere on mei-yu front lows cannot be ignored.

Periodontal evaluation in patients undergoing maxillary expansion.

PubMed

Carmen, M; Marcella, P; Giuseppe, C; Roberto, A

2000-09-01

Maxillary transverse diameter expansion is a treatment various authors have claimed is related to the development of gingival recession on the teeth of the upper arch. The aim of the present study was to compare such an incidence in two different groups of patients: those treated with surgically assisted rapid maxillary expansion and orthopedic expansion, respectively. Both treatments achieved the goal of expanding the transverse dimension (5.3 and 4.4 mm, respectively), but a significant difference was shown by the chi 2 test for the incidence of gingival recession of premolar/molar upper teeth, more than double for the latter than for the former. Therefore, surgically assisted rapid maxillary expansion seems to be an orthodontically effective procedure, safer than the orthopedic treatment regarding the possible development of mucogingival problems.

[Clinical examination of children with tooth aplasia. Correlations between dental symptoms and the whole organism].

PubMed

Knolmayer, Judit; Bognár, Veronika; Szabó, Gyula

2008-10-01

The characteristic abnormalities of jaws, teeth, and salivation can be measured and expressed by numbers. The possible etiological factors, like the positive family history of noxas during the pregnancy can be explored. In our study we examined the symptoms of general organic system and teeth trait--jaw relation, seriousness of aplasia, abnormalities of teeth in size--defect of salivary glands and the presence of possible etiological factors. Thirty children were examined. The symptoms of general organic system were diagnosed. 60% of tooth agenesis occurs in the maxilla, the size of teeth reduced also in the upper jaw. Pseudoprogenia can be explained by these facts. The size reduction of extant teeth appeared stronger in the labiolingual direction. The salivary secretion rate in examined children proved significantly lower than in the control group. Seven siblings and eight parents were identified by examining the etiological factors. We did not find any noxas during the pregnancy by our questionnaire method.

Enameloid microstructure of the serrated cutting edges in certain fossil carcharhiniform and lamniform sharks.

PubMed

Andreev, Plamen S

2010-07-01

The triple-layered enameloid organization of neoselachian teeth has proven to be a reliable systematic character of the group. This study uses scanning electron microscopy to investigate the orientation of the parallel enameloid bundles in the area of the serrated cutting edges in certain fossil elasmobranchs. The examined teeth come from two Upper Cretaceous Squalicorax species and the Upper Miocene carcharhiniforms Galeocerdo sp., Carcharhinus sp., and Hemipristis serra. The parallel bundles are revealed by surface etching, which removes the superficial shiny-layered enameloid. In the teeth of Squalicorax, the bundles around the cutting edge bend once, before they reach the serrations. The studied carcharhiniform species show a more complicated pattern with a change of parallel bundle course inside the serrations. H. serra teeth do not display the first bending of the bundles, whereas it was present in the other two carcharhiniforms. The course of the crystalline bundles in both Squalicorax species is not affected by the presence of the serrations, regardless of the twofold difference in tooth size between them. In the carcharhiniform species, the bended bundles occur within the primary and secondary serrations and are always associated with them. This feature might have functional significance by strengthening the cutting edge or could simply develop as a consequence of the enameloid mineralization around the individual serrae. (c) 2009 Wiley-Liss, Inc.

Shear bond strength and enamel fracture behavior of ceramic brackets Fascination® and Fascination®2.

PubMed

Gittner, Robert; Müller-Hartwich, Ralf; Engel, Sylvia; Jost-Brinkmann, Paul-Georg

2012-01-01

The purpose of this study was to compare the shear bond strength and incidence of enamel fractures of the ceramic brackets Fascination® and Fascination®2. A total of 360 teeth (180 first upper bicuspids and 180 lower incisors) were stored in 96% ethanol, while 360 other teeth (180 first upper bicuspids and 180 lower incisors) were stored in 0.1% thymol. All 720 teeth were bonded one-half each with Fascination® and Fascination®2 brackets using three different adhesives and three different light curing units. The teeth were debonded with a debonding-device according to DIN EN ISO 10477 using a universal testing machine with a crosshead speed of 1 mm per minute. The enamel surface was then examined stereomicroscopically (10x and 40x magnification). The non-parametric Mann-Whitney U test was used, since the data were not normally distributed. The Fascination®2 brackets provided significantly lower shear bond strength than Fascination® brackets (p = 0.003). Fascination® brackets demonstrated significantly fewer, smaller enamel fractures than Fascination®2 brackets (p = 0.012). The lower shear bond strength of the Fascination®2 brackets is clinically acceptable, but our study's experimental design did not enable us to prove whether this is clinically associated with a lower risk of enamel fracture.

UV EFFECTS IN TOOTH ENAMEL AND THEIR POSSIBLE APPLICATION IN EPR DOSIMETRY WITH FRONT TEETH

PubMed Central

Sholom, S.; Desrosiers, M.; Chumak, V.; Luckyanov, N.; Simon, S.L.; Bouville, A.

2009-01-01

The effects of ultraviolet (UV) radiation on ionizing radiation biodosimetry were studied in human tooth enamel samples using the technique of electron paramagnetic resonance (EPR) in X-band. For samples in the form of grains, UV-specific EPR spectra were spectrally distinct from that produced by exposure to gamma radiation. From larger enamel samples, the UV penetration depth was determined to be in the 60–120 μm range. The difference in EPR spectra from UV exposure and from exposure to gamma radiation samples was found to be a useful marker of UV equivalent dose (defined as the apparent contribution to the gamma dose in mGy that results from UV radiation absorption) in tooth enamel. This concept was preliminarily tested on front teeth from inhabitants of the region of the Semipalatinsk Nuclear Test Site (Kazakhstan) who might have received some exposure to gamma radiation from the nuclear tests conducted there as well as from normal UV radiation in sunlight. The technique developed here to quantify and subtract the UV contribution to the measured tooth is currently limited to cumulative dose measurements with a component of UV equivalent dose equal to or greater than 300 mGy. PMID:20065706

Sinus Headaches

MedlinePlus

... Achy feeling in your upper teeth Sinusitis or migraine? Migraines and headaches from sinusitis are easy to confuse ... types of headaches may overlap. Both sinusitis and migraine headache pain often gets worse when you bend ...

The earliest herbivorous marine reptile and its remarkable jaw apparatus.

PubMed

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C

2016-05-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles.

Fronts and frontogenesis as revealed by high time resolution data

NASA Technical Reports Server (NTRS)

Frank, A. E.; Barber, D. A.

1977-01-01

Upper air sounding are used to examine a cold front of average intensity. Vertical cross sections of potential temperature and wind, and horizontal analyses were compared and adjusted for consistency. These analyses were then used to study the evolution of the front, found to consist of a complex system of fronts occurring at all levels of the troposphere. Low level fronts were strongest at the surface and rapidly weakened with height. Fronts in the midddle troposphere were much more intense. The warm air ahead of the fronts was nearly barotropic, while the cold air behind was baroclinic through deep layers. A deep mixed layer was observed to grow in this cold air.

Submesoscale-selective compensation of fronts in a salinity-stratified ocean

PubMed Central

Spiro Jaeger, Gualtiero; Mahadevan, Amala

2018-01-01

Salinity, rather than temperature, is the leading influence on density in some regions of the world’s upper oceans. In the Bay of Bengal, heavy monsoonal rains and runoff generate strong salinity gradients that define density fronts and stratification in the upper ~50 m. Ship-based observations made in winter reveal that fronts exist over a wide range of length scales, but at O(1)-km scales, horizontal salinity gradients are compensated by temperature to alleviate about half the cross-front density gradient. Using a process study ocean model, we show that scale-selective compensation occurs because of surface cooling. Submesoscale instabilities cause density fronts to slump, enhancing stratification along-front. Specifically for salinity fronts, the surface mixed layer (SML) shoals on the less saline side, correlating sea surface salinity (SSS) with SML depth at O(1)-km scales. When losing heat to the atmosphere, the shallower and less saline SML experiences a larger drop in temperature compared to the adjacent deeper SML on the salty side of the front, thus correlating sea surface temperature (SST) with SSS at the submesoscale. This compensation of submesoscale fronts can diminish their strength and thwart the forward cascade of energy to smaller scales. During winter, salinity fronts that are dynamically submesoscale experience larger temperature drops, appearing in satellite-derived SST as cold filaments. In freshwater-influenced regions, cold filaments can mark surface-trapped layers insulated from deeper nutrient-rich waters, unlike in other regions, where they indicate upwelling of nutrient-rich water and enhanced surface biological productivity. PMID:29507874

Molar loss and powder diet leads to memory deficit and modifies the mRNA expression of brain-derived neurotrophic factor in the hippocampus of adult mice.

PubMed

Takeda, Yosuke; Oue, Hiroshi; Okada, Shinsuke; Kawano, Akira; Koretake, Katsunori; Michikawa, Makoto; Akagawa, Yasumasa; Tsuga, Kazuhiro

2016-12-05

It is known that tooth loss is known to be a risk factor for Alzheimer's disease and soft diet feeding induces memory impairment. Recent studies have shown that brain-derived neurotrophic factor (BDNF) is associated with tooth loss or soft diet in young animal model, and that BDNF expression is decreased in patients with Alzheimer's disease. However, single or combined effect of tooth loss and/or soft diet on brain function has not fully understood. Here we examined the effect of molar loss and powder diet on memory ability and the expression of BDNF mRNA in the hippocampus of adult C57BL/6J mice. Twenty eight-weeks-old C57BL/6J mice were divided into intact molar group and extracted molar group. They were randomly divided into the I/S group (Intact upper molar teeth/Solid diet feeding), the E/S group (Extracted upper molar teeth/Solid diet feeding), the I/P group (Intact upper molar teeth/Powder diet feeding), and the E/P group (Extracted upper molar teeth/Powder diet feeding). The observation periods were 4 and 16-week. To analyze the memory ability, the step-through passive avoidance test was conducted. BDNF-related mRNA in the hippocampus was analyzed by real-time polymerase chain reaction (RT-PCR). At 4 weeks later, we performed memory test and isolated brains to analyze. There were no differences in memory function and BDNF mRNA level between these four groups. However, at 16 weeks later, E/S and E/P group showed memory impairment, and decreased level of BDNF mRNA. Whereas, the powder diet had no effect on memory function and BDNF mRNA level even at 16 weeks later. These results suggest that the effect of molar loss and powder diet on memory function and BDNF mRNA levels were different, molar loss may have a greater long-term effect on memory ability than powder diet does.

The thermodynamic and dynamical features of double front structures during 21 31 July 1998 in China

NASA Astrophysics Data System (ADS)

Zhou, Yushu; Deng, Guo; Lei, Ting; Ju, Jianhua

2005-11-01

The daily 1° × 1° data of the Aviation (AVN) model, the black body temperature (TBB) data of cloud top, and cloud images by geostationary meteorological satellite (GMS) are used to identify a dew-point front near the periphery of the western Pacific subtropical high (WPSH). The results clearly demonstrate the existence of the dew-point front, and its thermodynamic and dynamic structural characteristics are analyzed in detail. The dew-point front is a transitional belt between the moist southwest monsoon flow and the dry adiabatic sinking flow near the WPSH, manifested by a large horizontal moisture gradient in the mid-lower troposphere and conjugated with the mei-yu front to form a predominant double-front structure associated with intense rainfall in the mei-yu period. The mei-yu front is located between 30° and 35°N, vertically extends from the ground level to the upper level and shifts northward. The dew-point front is to the south of the mei-yu front and lies up against the periphery of the WPSH. Generally, it is located between 850 hPa and 500 hPa. On the dew-point front side, the southwesterly prevails at the lower level and the northeasterly at the upper level; this wind distribution is different from that on the mei-yu front side. Vertical ascending motion exists between the two fronts, and there are descending motions on the north side of the mei-yu front and on the south side of the dew-point front, which form a secondary circulation. The dynamics of the double fronts also have some interesting features. At the lower level, positive vertical vorticity and obvious convergence between the two fronts are clearly identified. At the mid-lower level, negative local change of the divergence (corresponding to increasing convergence) is often embedded in the two fronts or against the mei-yu front. Most cloud clusters occur between the two fronts and propagate down stream in a wave-like manner.

Obstructive Sleep Apnea Syndrome in a Pubescent Boy of Short Stature Was Improved with an Orthodontic Mandibular Advancement Oral Appliance: A Case Report

PubMed Central

Ito, Shin; Otake, Hironao; Tsuiki, Satoru; Miyao, Etsuko; Noda, Akiko

2015-01-01

We report a 16-year-old pubescent pediatric patient with obstructive sleep apnea syndrome (OSAS) and short stature whose apnea hypopnea index (AHI) was significantly reduced following the use of an orthodontic oral appliance that advances the mandible ventrally. The mandible was advanced 64% of the maximal mandibular protrusive position with use of the appliance over a 3-year period. The patient's AHI without the appliance in place decreased from 101.6/h at baseline to 11/h after treatment. Moreover, the patient's height increased 14 cm during treatment, resulting in height close to the average height for his age. Cephalometric analysis revealed an improvement in his retrognathic mandible and proclination of the upper front teeth. In conclusion, an orthodontic mandibular advancement oral appliance played an important role not only in improving the patient's OSAS but also in normalizing his physical growth during puberty. Citation: Ito S, Otake H, Tsuiki S, Miyao E, Noda A. Obstructive sleep apnea syndrome in a pubescent boy of short stature was improved with an orthodontic mandibular advancement oral appliance: a case report. J Clin Sleep Med 2015;11(1):75–76. PMID:25348240

A revision of hominin fossil teeth from Fontana Ranuccio (Middle Pleistocene, Anagni, Frosinone, Italy).

PubMed

Rubini, Mauro; Cerroni, Vittorio; Festa, Giulia; Sardella, Raffaele; Zaio, Paola

2014-12-01

The Fontana Ranuccio hominin teeth (FR, Latium, Italy) are dated to the Middle Pleistocene. In previous studies these teeth were classified as two lower (left and right) second molars, one lower left central incisor and a badly worn incisor crown, the exact position of which could not be determined. In 2012 these remains were acquired by the Anthropological Service of S.B.A.L. (Italian Ministry of Culture) and for this reason re-analysed. In a thorough revision we have reassessed them both morphologically and dimensionally as two lower (left and right) first molars, one lower left lateral incisor and a possible upper left canine. The comparison with penecontemporaneous and diachronic samples shows that the Fontana Ranuccio teeth are morphologically similar to Atapuerca-Sima de los Huesos, Arago XIII and Neanderthal samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Overlays or ceramic fragments for tooth restoration: an analysis of fracture resistance.

PubMed

Tavarez, Rudys Rodolfo de Jesus; Firoozmand, Leily Macedo; Silva, Mônica Barros; Malheiros, Adriana Santos; Bandéca, Matheus Coelho

2014-01-01

The aim of this study was to evaluate the mode of fracture and resistance of partial ceramic restorations of posterior teeth. Thirty healthy upper premolars were selected and divided into three groups (n = 10): Group 1- control, healthy unrestored teeth, group 2-teeth restored with ceramic fragments; and group 3-teeth restored with ceramic overlays. The restorations were manufactured with feldspathic ceramic and cemented with RelyX ARC resin cement. After being stored in distilled water for 7 days, the teeth were subjected to axial compression mechanical testing with a universal testing machine. Force was applied to the long axis of the tooth at a speed of 0.5 mm/min until fracture. The data were analyzed with one-way ANOVA and Tukey's test (5%). The mode of fracture was scored according to the degree of involvement of the tooth structure and the type of restoration. A significant difference (p < 0.05) was showed between groups 2 (1155 N) and 3 (846.6 N), but there was no significant difference between group 1 and the other groups (1046 N), More extensive fractures were prevalent in the healthy teeth group (Group 1), which had no occlusal coverage; less severe fractures were found in groups 2 and 3. We conclude that teeth restored with ceramic fragments may offer greater resistance to fractures compared to teeth that have overlay restorations.

Occurrence and severity of enamel decalcification adjacent to bracket bases and sub-bracket lesions during orthodontic treatment with two different lingual appliances

PubMed Central

Klang, Elisabeth; Helms, Hans-Joachim; Wiechmann, Dirk

2016-01-01

Summary Background: Using lingual enamel surfaces for bracket placement not only has esthetic advantages, but may also be suitable in terms of reducing frequencies of enamel decalcifications. Objective: To test the null-hypothesis that there is no significant difference in enamel decalcification or cavitation incidence adjacent to and beneath bracket bases between two lingual multi-bracket (MB) appliances that are different in terms of design, material composition, and manufacturing technology (group A: WIN, DW-LingualSystems; group B: Incognito, 3M-Unitek), taking into account patient- and treatment-related variables on white spot lesion (WSL) formation. Methods: Standardized, digital, top-view photographs of 630 consecutive subjects (16214 teeth; n Incognito = 237/6076 teeth; n WIN = 393/10138 teeth; mean age: 17.47±7.8; m/f 43.2/56.8%) with completed lingual MB treatment of the upper and lower permanent teeth 1–7 were screened for decalcification or cavitation adjacent to and beneath the bracket bases before and after treatment, scored from 0 to 7. Non-parametric ANOVA was used for main effects ‘appliance type’, ‘gender’, ‘treatment complexity’, ‘grouped age’ (≤16/>16 years), and ‘treatment duration’ as covariable, at an α-level of 5%. Results: About 2.57% [5.94%] of all teeth in group A [B] developed decalcifications. Subject-related incidence was 9.59% [16.17%] for upper incisors in group A [B], and 12.98% [25.74%] for all teeth 16–46. There were significant effects by gender, age, and treatment duration. Conclusion: The null-hypothesis was rejected: sub-bracket lesions were significantly less frequent in group A, while frequencies of WSL adjacent to brackets were not significantly affected by appliance type. In view of the overall low incidences of lingual post-orthodontic white-spot lesions, the use of lingual appliances is advocated as a valid strategy for a reduction of enamel decalcifications during orthodontic treatment. PMID:26420772

Spatial and functional modeling of carnivore and insectivore molariform teeth.

PubMed

Evans, Alistair R; Sanson, Gordon D

2006-06-01

The interaction between the two main competing geometric determinants of teeth (the geometry of function and the geometry of occlusion) were investigated through the construction of three-dimensional spatial models of several mammalian tooth forms (carnassial, insectivore premolar, zalambdodont, dilambdodont, and tribosphenic). These models aim to emulate the shape and function of mammalian teeth. The geometric principles of occlusion relating to single- and double-crested teeth are reviewed. Function was considered using engineering principles that relate tooth shape to function. Substantial similarity between the models and mammalian teeth were achieved. Differences between the two indicate the influence of tooth strength, geometric relations between upper and lower teeth (including the presence of the protocone), and wear on tooth morphology. The concept of "autocclusion" is expanded to include any morphological features that ensure proper alignment of cusps on the same tooth and other teeth in the tooth row. It is concluded that the tooth forms examined are auto-aligning, and do not require additional morphological guides for correct alignment. The model of therian molars constructed by Crompton and Sita-Lumsden ([1970] Nature 227:197-199) is reconstructed in 3D space to show that their hypothesis of crest geometry is erroneous, and that their model is a special case of a more general class of models. (c) 2004 Wiley-Liss, Inc.

Dental health state utility values associated with tooth loss in two contrasting cultures.

PubMed

Nassani, M Z; Locker, D; Elmesallati, A A; Devlin, H; Mohammadi, T M; Hajizamani, A; Kay, E J

2009-08-01

The study aimed to assess the value placed on oral health states by measuring the utility of mouths in which teeth had been lost and to explore variations in utility values within and between two contrasting cultures, UK and Iran. One hundred and fifty eight patients, 84 from UK and 74 from Iran, were recruited from clinics at University-based faculties of dentistry. All had experienced tooth loss and had restored or unrestored dental spaces. They were presented with 19 different scenarios of mouths with missing teeth. Fourteen involved the loss of one tooth and five involved shortened dental arches (SDAs) with varying numbers of missing posterior teeth. Each written description was accompanied by a verbal explanation and digital pictures of mouth models. Participants were asked to indicate on a standardized Visual Analogue Scale how they would value the health of their mouth if they had lost the tooth/teeth described and the resulting space was left unrestored. With a utility value of 0.0 representing the worst possible health state for a mouth and 1.0 representing the best, the mouth with the upper central incisor missing attracted the lowest utility value in both samples (UK = 0.16; Iran = 0.06), while the one with a missing upper second molar the highest utility values (0.42, 0.39 respectively). In both countries the utility value increased as the tooth in the scenario moved from the anterior towards the posterior aspect of the mouth. There were significant differences in utility values between UK and Iranian samples for four scenarios all involving the loss of anterior teeth. These differences remained after controlling for gender, age and the state of the dentition. With respect to the SDA scenarios, a mouth with a SDA with only the second molar teeth missing in all quadrants attracted the highest utility values, while a mouth with an extreme SDA with both missing molar and premolar teeth in all quadrants attracted the lowest utility values. The study provided further evidence of the validity of the scaling approach to utility measurement in mouths with missing teeth. Some cross-cultural variations in values were observed but these should be viewed with due caution because the magnitude of the differences was small.

Heritability estimates of dental arch parameters in Lithuanian twins.

PubMed

Švalkauskienė, Vilma; Šmigelskas, Kastytis; Šalomskienė, Loreta; Andriuškevičiūtė, Irena; Šalomskienė, Aurelija; Vasiliauskas, Arūnas; Šidlauskas, Antanas

2015-01-01

The genetic influence on dental arch morphology may be country-specific, thus it is reasonable to check the estimates of genetics across different populations. The purpose of this study was to evaluate the heredity of dental arch morphology in the sample of Lithuanian twins with accurate zygosity determination. The study sample consisted of digital dental models of 40 monozygotic (MZ) and 32 dizygotic (DZ) twin pairs. The estimates of heritability (h(2)) for dental arch breadth and length were calculated. All dental arch breadths and lengths were statistically significantly larger in men than in women. Arch length differences between genders were less expressed than largest breadth differences. In the upper jaw the largest genetic effect was found on the arch breadth between lateral incisors. The heritability of dental arch length demonstrated similar differences between upper and lower jaw with mandible dental arch length being more genetically determined. The largest genetic impact was found on the upper dental arch breadth between lateral incisors. Similar, but lower heritability is inherent for canines and first premolars of the upper jaw and first premolars of the lower jaw. It also can be noted, that arch breadths between posterior teeth show lower heritability estimates than between anterior teeth on both jaws. The dental arch in the upper jaw has more expressed genetic component than in the lower jaw.

78 FR 21537 - Drawbridge Operation Regulations; Upper Mississippi River, Rock Island, IL

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-11

... Operation Regulations; Upper Mississippi River, Rock Island, IL AGENCY: Coast Guard, DHS. ACTION: Notice of... operating schedule that governs the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation is necessary to allow the Front Street 5K Run...

Severe maxillary osteomyelitis in a Gray Wolf (Canis lupus)

USGS Publications Warehouse

Barber-Meyer, Shannon

2012-01-01

Dental injuries to or abnormalities in functionally important teeth and associated bones in predators may significantly reduce the ability to kill and consume prey (Lazar et al. 2009). This impairment is likely exacerbated in coursing predators, such as Gray Wolves, that bite and hold onto fleeing and kicking prey with their teeth. Damage to carnassials (upper fourth premolar, P4, and lower first molar, M1) and associated bones in Gray Wolves may especially inhibit the consumption of prey because these teeth slice meat and crush bone. Here I report maxillary osteomyelitis involving the carnassials in a wild Gray Wolf from northeastern Minnesota of such severity that I hypothesize it ultimately caused the Gray Wolf to starve to death.

Biologic restoration of a traumatized maxillary central incisor in a toddler: a case report.

PubMed

John, Sheen Ann; Anandaraj, S; George, Sageena

2014-01-01

Trauma to the anterior teeth is relatively common in young children and teenagers. Traumatized anterior teeth require quick functional and aesthetic repair, and poses a challenge to the dental practitioner owing to the lack of co-operation ceded and the longer time invested. Reattachment of tooth fragment should be the first choice to restoring teeth when a usable fragment is available, since it gives a psychological and aesthetic advantage over the conventional technique. With the vast improvement in adhesive technology, reattachment is definitely a predictable treatment option for very young children. This paper describes the treatment of a 2½ year old female child who sustained crown-root fracture, extending subgingivally, in primary upper central incisor.

The earliest herbivorous marine reptile and its remarkable jaw apparatus

PubMed Central

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C.

2016-01-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles. PMID:27386529

Dental occlusion analysis in the Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times in Serbia: Tooth size comparison in skeletal samples.

PubMed

Pajević, Tina; Glišić, Branislav

2017-05-01

Anthropological studies have reported that tooth size decreases in the context of diet changes. Some investigations have found a reverse trend in tooth size from the prehistoric to the modern times. The aims of this study were to analyze tooth size in skeletal samples from Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times to determine sex differences and establish a temporal trend in tooth size in the aforementioned periods. Well-preserved permanent teeth were included in the investigation. The mesiodistal (MD) diameter of all teeth and buccolingual (BL) diameter of the molars were measured. Effects of sex and site were tested by one-way ANOVA, and the combined effect of these factors was analyzed by UNIANOVA. Sexual dimorphism was present in the BL diameters of all molars and MD diameters of the upper first and the lower third molar. The lower canine was the most dimorphic tooth in the anterior region. The MD diameter of most teeth showed no significant difference between the groups, (sample from: Mesolithic-Neolithic Age-group 1; Bronze Age-group 2; Roman times-group 3; Medieval times-group 4), whereas the BL diameters of the upper second and the lower first molar were the largest in the first group. Multiple comparisons revealed a decrease in the BL diameter of the upper second and the lower first molar from the first to the later groups. Lower canine MD diameter exhibited an increase in the fourth group compared to the second group. On the basis of the MD diameter, a temporal trend could not be observed for most of the teeth. The lower canine exhibited an increase in the MD diameter from the prehistoric to the Medieval times. Changes of BL diameter were more homogeneous, suggesting that the temporal trend of molar size decreased from the Mesolithic-Neolithic to Medieval times in Serbia. Copyright © 2017. Published by Elsevier Ltd.

Smile attractiveness. Self-perception and influence on personality.

PubMed

Van der Geld, Pieter; Oosterveld, Paul; Van Heck, Guus; Kuijpers-Jagtman, Anne Marie

2007-09-01

To investigate self-perception of smile attractiveness and to determine the role of smile line and other aspects correlated with smile attractiveness and their influence on personality traits. Participants judged their smile attractiveness with a patient-specific questionnaire. The questionnaire contained a spontaneous smiling photograph of the participant. Objective smile-line height was measured using a digital videographic method for smile analysis. Personality was assessed with the Dutch Personality Index. Cronbach's alpha for the smile judgment questionnaire was .77. The results showed that size of teeth, visibility of teeth, and upper lip position were critical factors in self-perception of smile attractiveness (social dimension). Color of teeth and gingival display were critical factors in satisfaction with smile appearance (individual dimension). Participants, smiling with teeth entirely displayed and some gingival display (two to four millimeters), perceived their smile line as most esthetic. Smiles with disproportional gingival display were judged negatively and correlated with the personality characteristics of neuroticism and self-esteem. Visibility and position of teeth correlated with dominance. The results of this research underpin the psychosocial importance and the dental significance of an attractive smile.

An analysis of maxillary anterior teeth: facial and dental proportions.

PubMed

Hasanreisoglu, Ufuk; Berksun, Semih; Aras, Kerem; Arslan, Ilker

2005-12-01

The size and form of the maxillary anterior teeth are important in achieving pleasing dental and facial esthetics. However, little scientific data have been defined as criteria for evaluating these morphological features. This study analyzed the clinical crown dimensions of maxillary anterior teeth to determine whether consistent relationships exist between tooth width and several facial measurements in a subset of the Turkish population. Full-face and anterior tooth images of 100 Turkish dental students viewed from the front and engaged in maximum smiling were recorded with digital photography under standardized conditions. Gypsum casts of the maxillary arches of the subjects were also made. The dimensions of the anterior teeth, the occurrence of the golden ratio, the difference between the actual and perceived sizes, and the relationship between the anterior teeth and several facial measurements by gender were analyzed using the information obtained from both the computer images and the casts. One-sample, 2-sample, and paired t tests, and repeated-measures analysis of variance and Duncan multiple-range tests were performed to analyze the data (alpha=.05). The dimensions of the central incisors (P<.05) and canines (P<.01) varied by gender. The existence of the so-called "golden proportion" for the maxillary anterior teeth as a whole was not found. Significant differences emerged when the mean ratios between various perceived widths were compared with their ideal golden ratios (P<.01). Proportional relationships between the bizygomatic width and the width of the central incisor, and the intercanine distance and the interalar width in women were observed. The maxillary central incisor and canine dimensions of men were greater than those of women in the Turkish population studied, with the canines showing the greatest gender variation. Neither a golden proportion nor any other recurrent proportion for all anterior teeth was determined. Bizygomatic width and interalar width may serve as references for establishing the ideal width of the maxillary anterior teeth, particularly in women.

Professional musicians with craniomandibular dysfunctions treated with oral splints.

PubMed

Steinmetz, Anke; Ridder, Paul H; Methfessel, Götz; Muche, Burkhard

2009-10-01

Craniomandibular dysfunction (CMD) symptoms occur frequently in violin/viola and wind players and can be associated with pain in the neck, shoulders and arm. In the current study, the effect of oral splint treatment of CMD on reducing pain and symptoms especially in these areas was investigated. Thirty (30) musicians undergoing CMD treatment with oral splints participated in this study. They completed a questionnaire that addressed CMD symptoms, localization of pain, and subjective changes in symptoms. Pain in the shoulder and/or upper extremity was the most frequent symptom reported by 83% of subjects, followed by neck pain (80%) and pain in the teeth/TMJ regions (63%). Treatment with oral splints contributed to a significant decrease in neck pain in 91%, teeth/TMJ pain in 83%, and shoulder and upper extremity pain in 76% of the musicians. Eighty percent (80%) of the patients reported improvement of their predominant symptoms. CMD can be a potential cause for pain in the neck, shoulders, and upper extremities of musicians. It is paramount that musicians with musculoskeletal problems be examined for CMD symptoms. Treatment with oral splints seems to be valuable. Further prospective, randomized controlled studies are necessary to confirm efficacy of oral splint treatment in CMD-associated pain and problems in the neck, shoulder, and the upper extremities in musicians.

Hydromechanical drilling device

DOEpatents

Summers, David A.

1978-01-01

A hydromechanical drilling tool which combines a high pressure water jet drill with a conventional roller cone type of drilling bit. The high pressure jet serves as a tap drill for cutting a relatively small diameter hole in advance of the conventional bit. Auxiliary laterally projecting jets also serve to partially cut rock and to remove debris from in front of the bit teeth thereby reducing significantly the thrust loading for driving the bit.

TMJ: Symptoms, Diagnosis and Treatment | NIH MedlinePlus the Magazine

MedlinePlus

... please turn Javascript on. Feature: TMJ TMJ: Symptoms, Diagnosis and Treatment Past Issues / Winter 2010 Table of ... way the upper and lower teeth fit together Diagnosis There is no standard test for diagnosing TMJ. ...

The tooth, the whole tooth and nothing but the tooth: tooth shape and ontogenetic shift dynamics in the white shark Carcharodon carcharias.

PubMed

French, G C A; Stürup, M; Rizzuto, S; van Wyk, J H; Edwards, D; Dolan, R W; Wintner, S P; Towner, A V; Hughes, W O H

2017-10-01

Results from this study of the white shark Carcharodon carcharias include measurements obtained using a novel photographic method that reveal significant differences between the sexes in the relationship between tooth cuspidity and shark total length, and a novel ontogenetic change in male tooth shape. Males exhibit broader upper first teeth and increased distal inclination of upper third teeth with increasing length, while females do not present a consistent morphological change. Substantial individual variation, with implications for pace of life syndrome, was present in males and tooth polymorphism was suggested in females. Sexual differences and individual variation may play major roles in ontogenetic changes in tooth morphology in C. carcharias, with potential implications for their foraging biology. Such individual and sexual differences should be included in studies of ontogenetic shift dynamics in other species and systems. © 2017 The Fisheries Society of the British Isles.

Oceanic front in the Greenhorn Sea (Late Middle through Late Cenomanian)

NASA Astrophysics Data System (ADS)

Fisher, C. G.; Hay, W. W.; Eicher, D. L.

1994-12-01

An abrupt lithofacies change between calcareous shale and noncalcareous shale occurs in strata deposited in the mid-Cretaceous Greenhorn Seaway in the southeastern corner of Montana. The facies were correlated lithostratigraphically using bentonites and calcarenites. The lithocorrelations were then refined using ammonites, foraminifera, and calcareous nannofossils. Twenty-five time slices were defined within the upper middle and lower upper Cenomanian strata. Biofacies analysis indicate that lithofacies changes record the boundary or oceanic front between two water masses with distinctly different paleoceanographic conditions. One water mass entered the seaway from the Arctic and the other from the Gulf of Mexico/Tethys. The microfauna and microflora permit interpretation of the environmental conditions in each water mass. At times when the front was near vertical, the two water masses were of the same density but of different temperatures and salinities.

4. VIEW EAST, SOUTHWEST FRONT, NORTHWEST SIDE Side elevation. Note ...

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

4. VIEW EAST, SOUTHWEST FRONT, NORTHWEST SIDE Side elevation. Note the ground floor windows which were added. Siding is vinyl, but the burned area exposes asbestos siding added when the rear and upper areas were converted to living spaces. - 510 Central Avenue (Commercial Building), Ridgely, Caroline County, MD

A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization

PubMed Central

2016-01-01

The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth. PMID:27528796

Trace-fossil and storm-deposit relationships of San Carlos formation, west Texas

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

Metz, C.L.; Bednarski, S.P.

1986-05-01

Two distinct assemblages of trace fossils are preserved in the storm deposits in delta-front facies of the Upper Cretaceous San Carlos Formation, west Texas. The assemblages represent two widely differing responses to storm deposition and sediment-trace-fossil relationships, indicating that other environmental parameters, probably water depth and oxygen levels, influenced trace-fossil distribution within the San Carlos delta front. Evidence of the storm-deposited nature of the sandstones includes a scoured basal contact, planar to hummocky cross-stratification, and a upper contact that is either ripple marked or is gradational with overlying shales.

Dental implants placement in paranoid squizofrenic patient with obsessive-compulsive disorder: A case report

PubMed Central

Castellanos-Cosano, Lizett; Corcuera-Flores, José-Ramón; Mesa-Cabrera, María; Cabrera-Domínguez, José; Torres-Lagares, Daniel; Machuca-Portillo, Guillermo

2017-01-01

Background Paranoid schizophrenia is a mental illness that involves no observable anatomical alteration. Main characteristic affects the personality of the individual, as well as areas of his own psychology. Case Report A 33-year-old man with paranoid schizophrenia and obsessive-compulsive disorder in treatment with Haloperidol, Oxcarbazepine, Olanzapine and Seroquel is presented. Dental exploration showed widespread decay mostly cervical with numerous root fragments, agenesis of lateral incisors, impacted wisdom teeth, missing teeth and malocclusion. Treatment plan included restoration of teeth decay, extractions of root fragments and implant-supported prostheses in bilateral upper lateral incisors for aesthetics reason. A previous consultation with a psychiatric specialist was performed and no contraindication were observed. A preliminary radiological examination was performed previous dental treatment and implant placement. Due to patient refusal to replace dental abscenses with implants, inform consent was signed up from his parents. After local anesthesia, first implant was placed at upper right lateral positions (Straumann Bone Level Ø 3.3 mm, length 10 mm). Two weeks later a second implant was placed at upper left lateral position (Straumann Bone Level Ø 3.3 mm, length 12 mm). The patient showed no postoperative complications. After implant placement, the patient attended scheduled review appointments. The prosthesis was placed after a 3-month period of osseointegration. Conclusions Implant placement can be considered a suitable option for people with mental disorders. A previous consultation with psychiatric specialists for conducting a good patient management is necessaire. Key words:Paranoid schizophrenia, obsessive-compulsive disorder, dental implants. PMID:29302292

A previously unreported association between Nance-Horan syndrome and spontaneous dental abscesses.

PubMed

Hibbert, Sally

2005-02-01

Atypical dentofacial structures may be the first indicator of other anomalies linked to a syndrome. This case describes the management of a 9-year-old girl referred for the routine management of supernumerary teeth. The anomalous form of her teeth, together with multiple supernumerary units and a history of congenital cataracts, were suggestive of a diagnosis of Nance-Horan syndrome. This is an X-linked disorder, in which females usually demonstrate mild expression; this case was unusual in respect to the marked phenotype expressed. Unusually, the girl developed 2 spontaneous abscesses of her noncarious upper incisor teeth; a feature never previously described in this syndrome. This report details the patient's dental management and discusses the possible pathogenesis of the dental abscesses, together with the genetic implications of this syndrome.

Late Middle Pleistocene hominin teeth from Panxian Dadong, South China.

PubMed

Liu, Wu; Schepartz, Lynne A; Xing, Song; Miller-Antonio, Sari; Wu, Xiujie; Trinkaus, Erik; Martinón-Torres, María

2013-05-01

The hominin teeth and evidence of hominin activities recovered from 1991 to 2005 at the Panxian Dadong site in South China are dated to the late Middle Pleistocene (MIS 8-6 or ca. 130-300 ka), a period for which very little is known about the morphology of Asian populations. The present study provides the first detailed morphometric description and comparisons of four hominin teeth (I(1), C1, P(3) and P3) from this site. Our study shows that the Panxian Dadong teeth combine archaic and derived features that align them with Middle and Upper Pleistocene fossils from East and West Asia and Europe. These teeth do not display any typical Neanderthal features and they are generally more derived than other contemporaneous populations from Asia and Africa. However, the derived traits are not diagnostic enough to specifically link the Panxian Dadong teeth to Homo sapiens, a common problem when analyzing the Middle Pleistocene dental record from Africa and Asia. These findings are contextualized in the discussion of the evolutionary course of Asian Middle Pleistocene hominins, and they highlight the necessity of incorporating the Asian fossil record in the still open debate about the origin of H. sapiens. Copyright © 2013 Elsevier Ltd. All rights reserved.

An harmonic smile resulted from the use of ceramic prosthesis with zirconia structure: a case report.

PubMed

Tavarez, Rudys Rodolfo de Jesus; Goncalves, Leticia Machado; Dias, Ana Paula; Dias, Anna Claudia Pereira; Malheiros, Adriana Santos; Silva, Alice Carvalho; Bandeca, Matheus Coelho

2014-06-01

The rehabilitation of patients requiring an esthetic smile demands a multidisciplinary approach. This clinical report describes a treatment plan for recovery aesthetics' smile of anterior teeth using ceramic prosthesis with zirconia structure. Initially, a review of aesthetic parameters, diagnostic waxing, mock-up and provisional restorations was performed. A contextual assessment of aesthetic, proportion and shape of teeth was done to recreate a natural looking for teeth in consonance with the smile line. Subsequently, based on these parameters, fixed prostheses of the upper anterior teeth using ceramic restorations with zirconia infrastructures were performed. The use of ceramic restorations with zirconia structures associated with a careful treatment plan allows the professional to integrate esthetic and function for satisfactory clinical results. How to cite the article: Tavarez RR, Gonçalves LM, Dias AP, Dias AC, Malheiros AS, Silva AC, Bandeca MC. An harmonic smile resulted from the use of ceramic prosthesis with zirconia structure: A case report. J Int Oral Health 2014;6(3):90-2.

Recolonization of mutans steptococci on teeth with orthodontic appliances after antimicrobial therapy.

PubMed

Attin, R; Thon, C; Schlagenhauf, U; Werner, C; Wiegand, A; Hannig, C; Attin, T

2005-10-01

The aim of the present study was to compare the recolonization pattern of mutans streptococci on densely colonized teeth with and without fixed orthodontic appliances after treatment with a 40 per cent chlorhexidine (CHX) varnish (EC 40, Explore). Healthy subjects free of carious lesions requiring fixed orthodontic appliance treatment but with high bacterial mutans streptococci saliva counts were recruited (n = 10). For baseline registration, plaque from buccal sites was sampled and cultivated on Dentocult strips. Following professional tooth cleaning, CHX varnish was applied to all teeth for 8 minutes. Subsequently, orthodontic brackets and bands were inserted in either the upper or lower arch. Eight weeks after varnish application the degree of recolonization with mutans streptococci was reassessed on the buccal sites. Statistical analysis showed that recolonization with mutans streptococci was significantly higher (P < 0.05) on teeth with orthodontic appliances. The results indicate that the use of fixed orthodontic appliances creates artificial environments suitable for the proliferation of mutans streptococci after CHX varnish suppression.

Smartphones and dental trauma: the current availability of apps for managing traumatic dental injuries.

PubMed

Djemal, Serpil; Singh, Parmjit

2016-02-01

There is a general consensus regarding the lack of awareness regarding the emergency management of traumatic dental injuries amongst laypersons and dental professionals. This article aims to provide an overview of the apps available for traumatic dental injuries using smartphones. These apps may serve as a gateway for raising awareness of traumatic dental injuries. Three smartphone devices were used to access their respective app stores (Nokia Lumia 635 with Windows Phone OS 8.1; iPhone 5 with iOS 8.1; Samsung Galaxy Ace II with Android OS v2.3.6 Gingerbread). Nine phrases were searched: broken tooth/teeth; chipped tooth/teeth; dental emergency; dental injury; dental trauma; fractured tooth/teeth; knocked-out tooth/teeth; tooth/teeth injury; and tooth/teeth trauma. Seven apps for the Android and one app for the Apple operating system were relevant. The only Apple iOS app retrieved (Dental Trauma) was also found for the Android OS (Dental Trauma First Aid) and had the endorsement of the International Association of Dental Traumatology. AcciDent was the only app dedicated to traumatic dental injuries targeted solely towards dental professionals. Five other apps (Chipped Tooth Solution, Dental Crown Repair, Fixing Cracked Tooth, Repairing the Front Tooth and Solution to Broken Tooth) appeared to come from the same source (KBES). No traumatic dental injury apps were found for the Windows Phone OS. There are apps available for both patients and dentists that range in quality and on the whole lack real-life photographs. Future apps should continue to provide good quality, evidence-based and validated material. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Visual monitoring of the melting front propagation in a paraffin-based PCM

NASA Astrophysics Data System (ADS)

Charvát, Pavel; Štětina, Josef; Mauder, Tomáš; Klimeš, Lubomír

Experiments were carried out in an environmental chamber with the aim to monitor the melting front propagation in a rectangular cavity filled with a paraffin-based Phase Change Material (PCM). The PCM was contained in transparent containers with the heat flux introduced by means of an electric heating element. The stabilized power source was used to maintain the constant heat output of the heating elements. The experiments were performed for the heat flux introduced at the side wall of the container and at the upper surface of the PCM. The paraffin-based PCM RT28HC with the phase change temperature of 28 °C was used in the experiments. The temperature in the environmental chamber was maintained at the melting temperature of the PCM. The propagation of the melting front was monitored with a digital camera and temperatures at several locations were monitored with RTDs and thermocouples. Significant natural convection was observed for the heat flux introduced at the side wall of the container. As a result the melting front propagated much faster at the top of the container than at its bottom. The heat flux introduced at the upper-surface of the PCM resulted in almost one-dimensional propagation of the melting front. The acquired data are to be used for validation of an in-house developed numerical model based on the front-tracking method.

3. SHOWING STREAM, STORE BUILDING (UPPER LEFT), SPRING HOUSE AND ...

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

3. SHOWING STREAM, STORE BUILDING (UPPER LEFT), SPRING HOUSE AND BATH HOUSE (NEAR STREAM), SOUTHEAST FRONTS AND SOUTHWEST SIDES (4 x 5 negative; 5 x 7 print) - Salt Sulpher Springs, U.S. Route 219, Salt Sulphur Springs, Monroe County, WV

Finishing occlusion in Class II or Class III molar relation: therapeutic Class II and III.

PubMed

Nangia, A; Darendeliler, M A

2001-11-01

The most frequent extraction regime consists of the removal of upper and lower premolars. Depending on anchorage requirements, camouflage treatment options, surgical intervention, or the absence of teeth in only one arch, it may become necessary to finalize the occlusion with a one-dental-unit discrepancy between the upper and lower dental arches. Guidelines are presented for finishing occlusions in Class II or Class III molar relation.

An objective isobaric/isentropic technique for upper air analysis

NASA Technical Reports Server (NTRS)

Mancuso, R. L.; Endlich, R. M.; Ehernberger, L. J.

1981-01-01

An objective meteorological analysis technique is presented whereby both horizontal and vertical upper air analyses are performed. The process used to interpolate grid-point values from the upper-air station data is the same as for grid points on both an isobaric surface and a vertical cross-sectional plane. The nearby data surrounding each grid point are used in the interpolation by means of an anisotropic weighting scheme, which is described. The interpolation for a grid-point potential temperature is performed isobarically; whereas wind, mixing-ratio, and pressure height values are interpolated from data that lie on the isentropic surface that passes through the grid point. Two versions (A and B) of the technique are evaluated by qualitatively comparing computer analyses with subjective handdrawn analyses. The objective products of version A generally have fair correspondence with the subjective analyses and with the station data, and depicted the structure of the upper fronts, tropopauses, and jet streams fairly well. The version B objective products correspond more closely to the subjective analyses, and show the same strong gradients across the upper front with only minor smoothing.

New dental and postcranial material of Agerinia smithorum (Primates, Adapiformes) from the type locality Casa Retjo-1 (early Eocene, Iberian Peninsula).

PubMed

Femenias-Gual, Joan; Marigó, Judit; Minwer-Barakat, Raef; Moyà-Solà, Salvador

2017-12-01

New material attributed to Agerinia smithorum from Casa Retjo-1 (early Eocene, NE Iberian Peninsula), consisting of 13 isolated teeth and a fragment of calcaneus, is studied in this work. These fossils allow the first description of the calcaneus and the upper premolars for the genus Agerinia, as well as the first description of the P 2 and M 2 for A. smithorum. The newly recovered lower teeth are virtually identical to the holotype of A. smithorum and are clearly distinguishable from the other species of Agerinia. The upper teeth also show clear differences with Agerinia marandati. The morphology of the calcaneal remains reveals that A. smithorum practiced a moderately active arboreal quadrupedal mode of locomotion, showing less leaping proclivity than notharctines but more than asiadapids. All the morphological features observed in the described material reinforce the hypothesis of a single lineage consisting of the species A. smithorum, A. marandati, and Agerinia roselli. Furthermore, the phylogenetic analysis developed in this work, which incorporates the newly described remains of A. smithorum, maintains the position of Agerinia as closely related to sivaladapids and asiadapids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients.

PubMed

Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-12-01

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

In vivo measurements of tooth wear over 12 months.

PubMed

Rodriguez, J M; Austin, R S; Bartlett, D W

2012-01-01

The aim of this study was to measure the progression of tooth wear in a cohort of 63 patients, 43 males and 20 females with a mean age of 39.1 years. Recruitment followed referral from general practice to Guy's Hospital for advice/management of tooth wear. Addition silicone impressions were taken at 6-month intervals for a total of 12 months; impressions were subsequently poured in type IV gypsum. Casts were scanned using a non-contacting laser profilometer and then superimposed using Geomagic® Qualify 11. Wear was measured in μm by tooth per time interval. A questionnaire highlighting dietary, parafunctional and gastric risk factors was obtained from each participant. Clustered multiple regression analysis was used to determine the relationship between tooth wear progression and risk factors. Maximum follow-up times were 6 months for 63 participants and 12 months for 30 participants. The measurement error was 15 μm. At the tooth level, 72.2% of 1,078 teeth wore <15 μm over a 6-month period. At the subject level, 77.7% of 63 participants showed median wear <15 μm over a 6-month period. There was a statistical trend towards tooth wear progression being associated with gastric risk factors (p < 0.05). The lower molars and the upper anterior teeth were the most commonly affected teeth; the lower molars and the upper central incisors were the most severely affected teeth. Tooth wear progression was slow in this cohort, suggesting that tooth wear may be cyclical and inactive in the majority of participants. Copyright © 2011 S. Karger AG, Basel.

Age-related changes of the dental aesthetic zone at rest and during spontaneous smiling and speech.

PubMed

Van der Geld, Pieter; Oosterveld, Paul; Kuijpers-Jagtman, Anne Marie

2008-08-01

The aims of this study were to analyse lip line heights and age effects in an adult male population during spontaneous smiling, speech, and tooth display in the natural rest position and to determine whether lip line height follows a consistent pattern during these different functions. The sample consisted of 122 randomly selected male participants from three age cohorts (20-25 years, 35-40 years, and 50-55 years). Lip line heights were measured with a digital videographic method for smile analysis, which had previously been tested and found reliable. Statistical analysis of the data was carried out using correlation analysis, analysis of variance, and Tukey's post hoc tests. Maxillary lip line heights during spontaneous smiling were generally higher in the premolar area than at the anterior teeth. The aesthetic zone in 75 per cent of the participants included all maxillary teeth up to the first molar. Coherence in lip line heights during spontaneous smiling, speech, and tooth display in the natural rest position was confirmed by significant correlations. In older subjects, maxillary lip line heights decreased significantly in all situations. Lip line heights during spontaneous smiling were reduced by approximately 2 mm. In older participants, the mandibular lip line heights also changed significantly and teeth were displayed less during spontaneous smiling. Mandibular tooth display in the rest position increased significantly. Upper lip length increased significantly by almost 4 mm in older subjects, whereas upper lip elevation did not change significantly. The significant increasing lip coverage of the maxillary teeth indicates that the effects of age should be included in orthodontic treatment planning.

Pulp histology after Er:YAG laser cavity preparation in subhuman primates--a pilot study.

PubMed

Louw, N P; Pameijer, C H; Ackermann, W D; Ertl, T; Cappius, H J; Norval, G

2002-08-01

The aim of the study was to make a direct comparison of the pulpal effects of laser and turbine preparations in subhuman primates. One female baboon (Papio Ursinus ursinus), weighing 15 kg, was used. General anaesthesia was administered (ketamine 100 mg/ml/kg body weight) and maintained with acepromazine (10 mg/ml/kg body weight). Class V cavities were prepared buccally in a total of 28 teeth (7 in each quadrant). Teeth in the upper right and lower left quadrants were prepared using a conventional 330 carbide bur in a high-speed fibre-optic handpiece with copious water spray. Teeth in the upper left and lower right quadrants were prepared using an Er:YAG laser drill (Fotona Twinlight, Llubljana, Slovenia) delivering 500 mJ at a pulse rate of 10 Hz and a wavelength of 2940 nm. The animal was sacrificed after 25 days. After general anaesthesia as described before, perfusion fixation of the head was accomplished with 10% neutral buffered formalin, pumped through a catheter inserted into the left carotid artery. The jaws were removed and, using a 330 carbide bur in a high speed handpiece, a continuous groove was cut through the bone and the roots at the level of the middle third of all the roots to promote thorough fixation of pulpal tissue. Decalcification and grading of the severity of the pulpal responses were conducted according to standard procedures. Owing to procedural errors seven teeth, FDI numbers 23, 24, 31, 34, 35, 44 and 45, had to be eliminated. The turbine-prepared teeth (N = 11) had a mean remaining dentine thickness (RDT) of 0.77 mm (SD = 0.42) and the laser-prepared teeth (N = 10) had a mean RDT of 0.81 mm (SD = 0.60). All pulps appeared normal except in one turbine-prepared tooth (12 with RDT = 0.20) and one laser-prepared tooth (27 with RDT = 0.30, where irreversible damage was caused. The only other deviations from normal were seen in the laser-treated 41 (RDT = 0.69) and the turbine-treated 36 (RDT = 0.77) where moderate hyperaemia was seen. Within the limitations of this study it can be concluded that there is no significant difference between dental pulp of teeth where Class V cavities were prepared with an Er:YAG laser drill compared with those prepared with a standard turbine drill.

[Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment].

PubMed

Wu, Jia-qi; Xu, Li; Liang, Cheng; Zou, Wei; Bai, Yun-yang; Jiang, Jiu-hui

2013-10-01

To evaluate the treatment time and the anterior and posterior teeth movement pattern as closing extraction space for the Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment. There were 10 skeletal Class III patients in accelerated osteogenic orthodontic group (AOO) and 10 patients in control group. Upper first premolars were extracted in all patients. After leveling and alignment (T2), corticotomy was performed in the area of maxillary anterior teeth to accelerate space closing.Study models of upper dentition were taken before orthodontic treatment (T1) and after space closing (T3). All the casts were laser scanned, and the distances of the movement of incisors and molars were digitally measured. The distances of tooth movement in two groups were recorded and analyzed. The alignment time between two groups was not statistically significant. The treatment time in AOO group from T2 to T3 was less than that in the control group (less than 9.1 ± 4.1 months). The treatment time in AOO group from T1 to T3 was less than that in the control group (less than 6.3 ± 4.8 months), and the differences were significant (P < 0.01). Average distances of upper incisor movement (D1) in AOO group and control group were (2.89 ± 1.48) and (3.10 ± 0.95) mm, respectively. Average distances of upper first molar movement (D2) in AOO group and control group were (2.17 ± 1.13) and (2.45 ± 1.04) mm, respectively.No statistically significant difference was found between the two groups (P > 0.05). Accelerated osteogenic orthodontic treatment could accelerate space closing in Class III surgical patients and shorten preoperative orthodontic time. There were no influence on the movement pattern of anterior and posterior teeth during pre-surgical orthodontic treatment.

Fracture resistance of pulpless teeth restored with post-cores and crowns.

PubMed

Hayashi, Mikako; Takahashi, Yutaka; Imazato, Satoshi; Ebisu, Shigeyuki

2006-05-01

The present study was designed to test the null hypothesis that there is no difference in the fracture resistance of pulpless teeth restored with different types of post-core systems and full coverage crowns. Extracted human upper premolars were restored with a fiber post, prefabricated metallic post or cast metallic post-core. Teeth with full crown preparations without post-core restorations served as a control. All teeth were restored with full coverage crowns. A 90-degree vertical or 45-degree oblique load was applied to the restored teeth with a crosshead speed of 0.5 mm/min, and the fracture loads and mode of fracture were recorded. Under the condition of vertical loading, the fracture load of teeth restored with the cast metallic post-cores was greatest among the groups (two-factor factorial ANOVA and Scheffe's F test, P<0.05). All fractures in teeth restored with all types of post-core systems propagated in the middle portions of roots, including the apices of the posts. Under the condition of oblique loading, the fracture load of teeth restored with pre-fabricated metallic posts was significantly smaller than that in other groups. Two-thirds of fractures in the fiber post group propagated within the cervical area, while most fractures in other groups extended beyond the middle of the roots. From the results of the present investigations, it was concluded that under the conditions of vertical and oblique loadings, the combination of a fiber post and composite resin core with a full cast crown is most protective of the remaining tooth structure.

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

PubMed

Asgary, Saeed; Fazlyab, Mahta; Nosrat, Ali

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

Artificial Bone and Teeth through Controlled Ice Growth in Colloidal Suspensions

NASA Astrophysics Data System (ADS)

Tomsia, Antoni P.; Saiz, Eduardo; Deville, Sylvain

2007-06-01

The formation of regular patterns is a common feature of many solidification processes involving cast materials. We describe here how regular patterns can be obtained in porous alumina and hydroxyapatite (HAP) by controlling the freezing of ceramic slurries followed by subsequent ice sublimation and sintering, leading to multilayered porous ceramic structures with homogeneous and well-defined architecture. These porous materials can be infiltrated with a second phase of choice to yield biomimetic nacre-like composites with improved mechanical properties, which could be used for artificial bone and teeth applications. Proper control of the solidification patterns provides powerful means of control over the final functional properties. We discuss the relationships between the experimental results, ice growth fundamentals, the physics of ice and the interaction between inert particles and the solidification front during directional freezing.

Artificial Bone and Teeth through Controlled Ice Growth in Colloidal Suspensions

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

Tomsia, Antoni P.; Saiz, Eduardo; Deville, Sylvain

2007-06-14

The formation of regular patterns is a common feature of many solidification processes involving cast materials. We describe here how regular patterns can be obtained in porous alumina and hydroxyapatite (HAP) by controlling the freezing of ceramic slurries followed by subsequent ice sublimation and sintering, leading to multilayered porous ceramic structures with homogeneous and well-defined architecture. These porous materials can be infiltrated with a second phase of choice to yield biomimetic nacre-like composites with improved mechanical properties, which could be used for artificial bone and teeth applications. Proper control of the solidification patterns provides powerful means of control over themore » final functional properties. We discuss the relationships between the experimental results, ice growth fundamentals, the physics of ice and the interaction between inert particles and the solidification front during directional freezing.« less

STEREO OBSERVATIONS OF FAST MAGNETOSONIC WAVES IN THE EXTENDED SOLAR CORONA ASSOCIATED WITH EIT/EUV WAVES

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

Kwon, Ryun-Young; Ofman, Leon; Kramar, Maxim

2013-03-20

We report white-light observations of a fast magnetosonic wave associated with a coronal mass ejection observed by STEREO/SECCHI/COR1 inner coronagraphs on 2011 August 4. The wave front is observed in the form of density compression passing through various coronal regions such as quiet/active corona, coronal holes, and streamers. Together with measured electron densities determined with STEREO COR1 and Extreme UltraViolet Imager (EUVI) data, we use our kinematic measurements of the wave front to calculate coronal magnetic fields and find that the measured speeds are consistent with characteristic fast magnetosonic speeds in the corona. In addition, the wave front turns outmore » to be the upper coronal counterpart of the EIT wave observed by STEREO EUVI traveling against the solar coronal disk; moreover, stationary fronts of the EIT wave are found to be located at the footpoints of deflected streamers and boundaries of coronal holes, after the wave front in the upper solar corona passes through open magnetic field lines in the streamers. Our findings suggest that the observed EIT wave should be in fact a fast magnetosonic shock/wave traveling in the inhomogeneous solar corona, as part of the fast magnetosonic wave propagating in the extended solar corona.« less

Quantification of upper limb kinetic asymmetries in front crawl swimming.

PubMed

Morouço, Pedro G; Marinho, Daniel A; Fernandes, Ricardo J; Marques, Mário C

2015-04-01

This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force-time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance. Copyright © 2015 Elsevier B.V. All rights reserved.

Musical Auditory Stimulation Influences Heart Rate Autonomic Responses to Endodontic Treatment

PubMed Central

Martiniano, Eli Carlos; Monteiro, Larissa Raylane Lucas; Valenti, Vitor E.; Sorpreso, Isabel Cristina Esposito; de Abreu, Luiz Carlos

2017-01-01

We aimed to evaluate the acute effect of musical auditory stimulation on heart rate autonomic regulation during endodontic treatment. The study included 50 subjects from either gender between 18 and 40 years old, diagnosed with irreversible pulpitis or pulp necrosis of the upper front teeth and endodontic treatment indication. HRV was recorded 10 minutes before (T1), during (T2), and immediately (T3 and T4) after endodontic treatment. The volunteers were randomly divided into two equal groups: exposed to music (during T2, T3, and T4) or not. We found no difference regarding salivary cortisol and anxiety score. In the group with musical stimulation heart rate decreased in T3 compared to T1 and mean RR interval increased in T2 and T3 compared to T1. SDNN and TINN indices decreased in T3 compared to T4, the RMSSD and SD1 increased in T4 compared to T1, the SD2 increased compared to T3, and LF (low frequency band) increased in T4 compared to T1 and T3. In the control group, only RMSSD and SD1 increased in T3 compared to T1. Musical auditory stimulation enhanced heart rate autonomic modulation during endodontic treatment. PMID:28182118

Migration of sharks into freshwater systems during the Miocene and implications for Alpine paleoelevation

NASA Astrophysics Data System (ADS)

Kocsis, László; Vennemann, Torsten W.; Fontignie, Denis

2007-05-01

Trace-element and isotopic compositions of fossilized shark teeth sampled from Miocene marine sediments of the north Alpine Molasse Basin, the Vienna Basin, and the Pannonian Basin generally show evidence of formation in a marine environment under conditions geochemically equivalent to the open ocean. In contrast, two of eight shark teeth from the Swiss Upper Marine Molasse locality of La Molière have extremely low δ18O values (10.3‰ and 11.3‰) and low 87Sr/86Sr ratios (0.707840 and 0.707812) compared to other teeth from this locality (21.1‰ 22.4‰ and 0.708421 0.708630). The rare earth element (REE) abundances and patterns from La Molière not only differ between dentine and enameloid of the same tooth, but also between different teeth, supporting variable conditions of diagenesis at this site. However, the REE patterns of enameloid from the “exotic” teeth analyzed for O and Sr isotopic compositions are similar to those of teeth that have O and Sr isotopic compositions typical of a marine setting at this site. Collectively, this suggests that the two “exotic” teeth were formed while the sharks frequented a freshwater environment with very low 18O-content and Sr isotopic composition controlled by Mesozoic calcareous rocks. This is consistent with a paleogeography of high-elevation (˜2300 m) Miocene Alps adjacent to a marginal sea.

Tracking the Polar Front south of New Zealand using penguin dive data

NASA Astrophysics Data System (ADS)

Sokolov, Serguei; Rintoul, Stephen R.; Wienecke, Barbara

2006-04-01

Nearly 36,000 vertical temperature profiles collected by 15 king penguins are used to map oceanographic fronts south of New Zealand. There is good correspondence between Antarctic Circumpolar Current (ACC) front locations derived from temperatures sampled in the upper 150 m along the penguin tracks and front positions inferred using maps of sea surface height (SSH). Mesoscale features detected in the SSH maps from this eddy-rich region are also reproduced in the individual temperature sections based on dive data. The foraging strategy of Macquarie Island king penguins appears to be influenced strongly by oceanographic structure: almost all the penguin dives are confined to the region close to and between the northern and southern branches of the Polar Front. Surface chlorophyll distributions also reflect the influence of the ACC fronts, with the northern branch of the Polar Front marking a boundary between low surface chlorophyll to the north and elevated values to the south.

Rossby waves, extreme fronts, and wildfires in southeastern Australia

NASA Astrophysics Data System (ADS)

Reeder, Michael J.; Spengler, Thomas; Musgrave, Ruth

2015-03-01

The most catastrophic fires in recent history in southern Australia have been associated with extreme cold fronts. Here an extreme cold front is defined as one for which the maximum temperature at 2 m is at least 17°C lower on the day following the front. An anticyclone, which precedes the cold front, directs very dry northerlies or northwesterlies from the interior of the continent across the region. The passage of the cold front is followed by strong southerlies or southwesterlies. European Centre for Medium-Range Weather Forecasts ERA-Interim Reanalyses show that this regional synoptic pattern common to all strong cold fronts, and hence severe fire conditions, is a consequence of propagating Rossby waves, which grow to large amplitude and eventually irreversibly overturn. The process of overturning produces the low-level anticyclone and dry conditions over southern Australia, while simultaneously producing an upper level trough and often precipitation in northeastern Australia.

Achieving an esthetic smile with fixed and removal prosthesis using extracoronal castable precision attachments

PubMed Central

Vaidya, Sharad; Kapoor, Charu; Bakshi, Yujika; Bhalla, Sonam

2015-01-01

Satisfactory restoration in a patient with a partially edentulous situation can be challenging especially when unilateral or bilateral posterior segment of teeth is missing. Successful restoration can be done with various conventional and contemporary treatment options. One such treatment modality is attachment-retained cast partial dentures. A key to success for an attachment retained cast partial denture is the strategic selection of teeth for retention. This clinical report discusses rehabilitation of a patient with the help of a combined prosthesis in the upper arch and stud retained overdenture in the lower arch. PMID:26929527

58. Aerial view looking east; Botany Worsted Mills at front, ...

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

58. Aerial view looking east; Botany Worsted Mills at front, Andrew McLean Company Textile Mill at upper right, Passaic River at rear - Dundee Canal Industrial Historic District, Beginning at George Street in Passaic & extending north along Dundee Canal approximately 1.2 miles to Canal headgates opposite East Clifton Avenue in Clifton, Passaic, Passaic County, NJ

10. INTERIOR OF LIVING ROOM SHOWING FRONT DOOR FLANKED BY ...

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

10. INTERIOR OF LIVING ROOM SHOWING FRONT DOOR FLANKED BY SLIDING GLASS WINDOWS AND ELECTRICAL WALL HEATER. ORIGINAL 1-LIGHT OVER 1-LIGHT, DOUBLE-HUNG WINDOW AT PHOTO RIGHT. CEILING VENT TO CHIMNEY AT RIGHT UPPER PHOTO CENTER. VIEW TO SOUTHEAST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

Disturbance Driven Rainfall in O`ahu, Hawai`i (1990-2010)

NASA Astrophysics Data System (ADS)

Longman, R. J.; Elison Timm, O.; Giambelluca, T. W.; Kaiser, L.; Newman, A. J.; Arnold, J.; Clark, M. P.

2017-12-01

Trade wind orographic rainfall is the most prevalent synoptic weather pattern in Hawai`i and provides a year-round source of moisture to the windward areas across the Island chain. Significant contributions to total and extreme precipitation have also been linked to one of four atmospheric disturbance situations that include: cold fronts, Kona storms, upper-tropospheric disturbances (upper level lows), and tropical systems. The primary objective of this research is to determine how these disturbance types contribute to total wet-season rainfall (RF) on the Island of O`ahu, Hawai`i and to identify any significant changes in the frequency of occurrence and or the intensity of these events. Atmospheric fronts that occurred in the Hawai`i region (17-26°N, 150-165°W) were extracted from a global dataset and combined with a Kona low and upper level low dataset to create a daily categorical weather classification time series (1990-2010). Mean rainfall was extracted from gridded daily O`ahu RF maps. Results show that the difference between a wet and dry year is predominantly explained by the RF contributions from disturbance events (r2 = 0.57, p < 0.01), in particularly, the contributions coming from Kona low and cold fronts that cross the Island. During the wettest season on record, disturbances accounted for 48% of the total RF, while during the driest season they accounted for only 6% of the total RF. The event-based RF analysis also compared the RF intensity in the absence of disturbance events with the average RF intensity on days when atmospheric fronts are present but do not cross the island. The results show that non-crossing fronts reduce the average RF intensity. A possible explanation is that these events are too far away to produce RF, but close enough to disrupt normal trade wind flow, thus limiting orographic RF on the island. This new event-based RF analysis has important implications for the projection of regional climate change in Hawai`i. Our results suggest that if storm tracks were to shift poleward, O`ahu wet season RF would be reduced. The most obvious effect is that fronts crossing the Island would likely occur less frequently reducing the number of days per year with heavy cold front rainfall. In addition, non-crossing fronts could occur more often and hence reducing the orographic RF.

Odontometric sex estimation from clinically extracted molar teeth in a North Indian population sample.

PubMed

Tabasum, Qutsia; Sehrawat, Jagmahender Singh; Talwar, Manjit Kaur; Pathak, Raj Kamal

2017-01-01

Different dental features have contributed significantly toward sex determination in the forensic anthropological contexts. Population-specific standards (discriminant functions or regression formulae) have been suggested for various population groups to identify the sex of an unknown individual from dental dimensions and other odontometric features. The main purpose of the present investigation was to examine the degree of sexual dimorphism exhibited by the human teeth of North Indians and identify importance as a forensic tool in sex determination. The linear and diagonal dimensions were recorded at both crown and cementoenamel junction levels of 58 upper and 72 lower molars of 130 Northwest Indian subjects (73 males and 57 females). The measurements were subjected to appropriate statistical analyses to estimate the sex estimation accuracy from lower and upper molars separately. Univariate analyses revealed that molar teeth had greater dimensions in males than the females and the mesiodistal cervical diameter (MDCV) was found to be the most suitable variable for sex determination of the molars. The classification results were in agreement with the previously conducted studies. The index of sexual dimorphism (ISD) was calculated to be higher in lower molars than the upper molars, and the highest sex differences were observed for MDCV based on the ISD. The overall sex estimation accuracy obtained from multivariate discriminant function analysis and regression analysis of pooled data was 70.0% (74% males, 64.9% females) and 66.9% (78.1% males, 52.6% females), respectively. Odontometrics can play a significant role in establishing the biological identity of an unknown individual even from a single tooth in the absence of other sophisticated molecular or biochemical techniques used for this purpose.

A geometric morphometric analysis of hominin lower molars: Evolutionary implications and overview of postcanine dental variation.

PubMed

Gómez-Robles, Aida; Bermúdez de Castro, José María; Martinón-Torres, María; Prado-Simón, Leyre; Arsuaga, Juan Luis

2015-05-01

Lower molars have been extensively studied in the context of hominin evolution using classic and geometric morphometric analyses, 2D and 3D approaches, evaluations of the external (outer enamel surface) and internal anatomy (dentine, pulp chamber, and radicular canals), and studies of the crown and root variation. In this study, we present a 2D geometric morphometric analysis of the crown anatomy of lower first, second, and third molars of a broad sample of hominins, including Pliocene and Lower, Middle, and Upper Pleistocene species coming from Africa, Asia, and Europe. We show that shape variability increases from first to second and third molars. While first molars tend to retain a relatively stable 5-cusped conformation throughout the hominin fossil record, second and third molars show marked distal reductions in later Homo species. This trend to distal reduction is similar to that observed in previous studies of premolars and upper second and third molars, and points to a correlated reduction of distal areas across the whole postcanine dentition. Results on lower molar variation, as well as on other postcanine teeth, show certain trends in European Pleistocene populations from the Atapuerca sites. Middle Pleistocene hominins from Sima de los Huesos show Neanderthal affinities and strong dental reduction, especially in the most distal molars. The degree of dental reduction in this population is stronger than that observed in classic Neanderthals. Homo antecessor hominins from Gran Dolina-TD6 have primitive lower teeth that contrast with their more derived upper teeth. The evolutionary implications of these dental affinities are discussed in light of recent paleogenetic studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Odontometric sex estimation from clinically extracted molar teeth in a North Indian population sample

PubMed Central

Tabasum, Qutsia; Sehrawat, Jagmahender Singh; Talwar, Manjit Kaur; Pathak, Raj Kamal

2017-01-01

Background: Different dental features have contributed significantly toward sex determination in the forensic anthropological contexts. Population-specific standards (discriminant functions or regression formulae) have been suggested for various population groups to identify the sex of an unknown individual from dental dimensions and other odontometric features. The main purpose of the present investigation was to examine the degree of sexual dimorphism exhibited by the human teeth of North Indians and identify importance as a forensic tool in sex determination. Materials and Methods: The linear and diagonal dimensions were recorded at both crown and cementoenamel junction levels of 58 upper and 72 lower molars of 130 Northwest Indian subjects (73 males and 57 females). The measurements were subjected to appropriate statistical analyses to estimate the sex estimation accuracy from lower and upper molars separately. Results: Univariate analyses revealed that molar teeth had greater dimensions in males than the females and the mesiodistal cervical diameter (MDCV) was found to be the most suitable variable for sex determination of the molars. The classification results were in agreement with the previously conducted studies. The index of sexual dimorphism (ISD) was calculated to be higher in lower molars than the upper molars, and the highest sex differences were observed for MDCV based on the ISD. The overall sex estimation accuracy obtained from multivariate discriminant function analysis and regression analysis of pooled data was 70.0% (74% males, 64.9% females) and 66.9% (78.1% males, 52.6% females), respectively. Conclusions: Odontometrics can play a significant role in establishing the biological identity of an unknown individual even from a single tooth in the absence of other sophisticated molecular or biochemical techniques used for this purpose. PMID:29657498

Histologic evaluation of the effect of mineral trioxide aggregate-Fillapex as a root canal sealer in rat teeth submitted to late replantation

PubMed Central

Ferreira, Manuel Marques; Botelho, Maria Filomena; Abrantes, Margarida; Carvalho, Lina; Carrilho, Eunice

2017-01-01

Objective: This study aims to analyze the effect of new root canal based silicate cement, in rat teeth after late replantation, comparing with calcium hydroxide (CH) in preventing tooth root resorption. Materials and Methods: The study group included 16 Wistar rats in which the upper right central incisors were extracted and were left on a worktable for 60 min, simulating a case of tooth avulsion, after had been anesthetized. One group, (Group I), the canals were filled with CH past, before replantation. The second groups of teeth, (Group II), the canals were filled with mineral trioxide aggregate-Fillapex (MTAF). After removal, the blood clot of the socket, with saline solution irrigation, the teeth were replanted into their original socket, and splinted with silk 3/0. The rats were sacrificed 8 weeks after replantation and the specimens were prepared for histologic and histomorphometric analyses. The areas of inflammatory and replacement resorptions were selected and quantified. These data for each group of teeth were evaluated and analyzed using the Mann–Whitney test (P = 0.05). Result and Conclusion: All the replanted teeth in both groups survived. Although root canal filled with MTAF provide better results than with CH past concerning inflammatory and replacement resorption, there was no statistical difference (P = 0.527). PMID:28435372

Prediction of unsaturated flow and water backfill during infiltration in layered soils

NASA Astrophysics Data System (ADS)

Cui, Guotao; Zhu, Jianting

2018-02-01

We develop a new analytical infiltration model to determine water flow dynamics around layer interfaces during infiltration process in layered soils. The model mainly involves the analytical solutions to quadratic equations to determine the flux rates around the interfaces. Active water content profile behind the wetting front is developed based on the solution of steady state flow to dynamically update active parameters in sharp wetting front infiltration equations and to predict unsaturated flow in coarse layers before the front reaches an impeding fine layer. The effect of water backfill to saturate the coarse layers after the wetting front encounters the impeding fine layer is analytically expressed based on the active water content profiles. Comparison to the numerical solutions of the Richards equation shows that the new model can well capture water dynamics in relation to the arrangement of soil layers. The steady state active water content profile can be used to predict the saturation state of all layers when the wetting front first passes through these layers during the unsteady infiltration process. Water backfill effect may occur when the unsaturated wetting front encounters a fine layer underlying a coarse layer. Sensitivity analysis shows that saturated hydraulic conductivity is the parameter dictating the occurrence of unsaturated flow and water backfill and can be used to represent the coarseness of soil layers. Water backfill effect occurs in coarse layers between upper and lower fine layers when the lower layer is not significantly coarser than the upper layer.

A retrospective evaluation of traumatic dental injury in children who applied to the dental hospital, Turkey.

PubMed

Sari, M E; Ozmen, B; Koyuturk, A E; Tokay, U; Kasap, P; Guler, D

2014-01-01

The purpose of this study was to analyze traumatic dental injuries in children visiting the dental hospital emergency department in Samsun of Turkey, in the period from 2007 to 2011. Data of age, gender, causes of dental trauma, injured teeth, type of dental injuries, the application period, the dental treatments, and traumatic dental injuries according to the seasons were obtained from the records at dental hospital. Of all 320 patients with traumatic dental injury, 205 were boys and 115 were girls with a boys/girls ratio 1.78:1. Traumatic dental injury was observed more frequently in the 7-12 age groups: 52.5% in girls and 67.8% in boys. Falls are the major cause of traumatic dental injury in the age group 6-12 (51.4%). Sport activities are a common cause of traumatic dental injury in the 7-12 age group (34.2%). Patients visited a dentist within approximately 2 h (57.1%). The upper anterior teeth were subjected to trauma more frequently than the lower anterior teeth. The maxillary central incisors were the most commonly affected teeth, and the mandibular canins were the least affected teeth. In primary teeth, avulsion was the most common type of dental injury (23%); on the other hand, enamel fractures were the most common type of dental injury (30.6%) observed in permanent teeth. In the primary dentition, the most commonly performed treatments were dental examination and prescribing (70%). The most common treatment choices in permanent teeth were restoration and dental examination (49.7 and 15.8%, respectively). The results of the study show that the emergency intervention to traumatized teeth is important for good prognosis of teeth and oral tissues. Therefore, the parents should be informed about dental trauma in schools, and dental hospital physicians should be subjected to postgraduate training.

21 CFR 872.3150 - Articulator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DENTAL DEVICES Prosthetic Devices § 872.3150 Articulator. (a) Identification. An articulator is a mechanical device intended to simulate movements of a patient's upper and lower jaws. Plaster casts of the patient's teeth and gums are placed in the device to reproduce the occlusion (bite) and articulation of...

European college of orthodontics: commission of affiliation and titularisation.

PubMed

Muller, Christine

2012-06-01

Date of birth: 28/4/1977; sex: female. A. (4/2006; 29 years). Tooth-arch discrepancy with bi-maxillary protrusion. Correction of bi-maxillary protrusion; avulsion of 15, 25, 35 and 45; fixed multi-bracket Incognito bi-maxillary appliance; mini-screw anchorage. B. POST-TREATMENT RECORDS DOCUMENTS: (9/2009; 32 years and 6 months). Permanent retainers using fixed upper and lower bonded wires. C. POST-RETENTION RECORDS: (7/2010; 33 years and 3 months). D. Reason for consultation: correction of crooked and "jutting" teeth. Extraoral examination: balanced facial levels; lateral view: predominant lower third; closed nasolabial angle; labial asymmetry with predominant lower lips. Endooral examination: young adult dentition; average dental status; large number of fillings; panorex confirms four devitalized teeth; good periodontal status; V-shaped upper arch with lingually ectopic 12 and 22; lower arch with slight incisor crowding; bi-lateral molar and canine Class I; crossbite of 12 and 22; 2-mm deepbite and 1-mm overjet. Copyright © 2012. Published by Elsevier Masson SAS.

Dental fragment embedded in the lower lip after facial trauma: Brief review literature and report of a case

PubMed Central

Lauritano, Dorina; Petruzzi, Massimo; Sacco, Gerardo; Campus, Guglielmo; Carinci, Francesco; Milillo, Lucio

2012-01-01

Upper incisors are the most frequently involved teeth in traumatic dental injuries. Soft tissues (lips and/or oral mucosa) adjacent to incisal edge can receive direct and/or indirect traumas. Laceration of the lower lip is a not rare eventuality and teeth fragments could be embedded in labial soft tissue. The reattachment of these fragments, if possible, is the elective treatment choice, thanks to the modern adhesive and restorative techniques. The authors present a case of a white Caucasian 10-year-old child, who attended the dental clinic for the treatment of both upper central incisors’ crown fractures. The fragment of the left incisor was retrieved embedded in the lower lip. It was successfully surgically removed and reattached using a composite adhesive technique. A careful clinical and radiographic examination with the surgical removal of tooth fragments could prevent undesirable foreign body reaction, infection and scarring. The authors also reviewed the most relevant literature concerning tooth fragment reattachment after removal from oral soft tissues. PMID:23814592

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

PubMed Central

Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-01-01

Purpose This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Materials and Methods Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. Results The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. Conclusion It might be possible to predict chronological age from the eruption height of the wisdom teeth. PMID:24380069

Tooth, skin, hair and eye colour interrelationships in Greek young adults.

PubMed

Lagouvardos, Panagiotis E; Tsamali, Ioana; Papadopoulou, Christine; Polyzois, Gregory

2013-01-01

The purpose of this study was to investigate the possible interrelationships of teeth, skin, eye and hair colour. A portable colorimeter (Shade Eye NCC/Shofu) was used to record the colour in the CIELAB system of the upper right incisors in 150 dental school students, along with their skin colour at three different areas. Natural hair and eye colour was classified into several categories by a trained examiner (ICC 0.93-0.99). One-way ANOVA and correlation tests were used to statistically analyse the data. Skin was found to have significantly higher L*, b* but lower a* values than teeth (p < 0.05). A significant correlation (p < 0.05) of teeth to skin L* and a*colour coordinate was found, but not to b* coordinate (p > 0.05). Hair tones were not correlated to teeth L* or b*, but only to a*coordinate. Teeth and eye colour coordinates were not correlated (p > 0.05). Eye and hair tones were found to have the highest significant correlation (ρ = 0.369). In conclusion, teeth of this cohort were found to be lighter, less red and yellow than the skin. Teeth colour was not related to eye colour, but lighter teeth were found to be associated with lighter skins, and redder lateral incisors to lighter hair. Darker facial skins or yellower forehead areas were also associated with darker hair and vice versa. The clinical relevance of the study is that the investigated facial characteristics are inter-correlated weakly to moderately, and for this reason predicting the colour parameters of one facial characteristic by another would not be accurate, but helpful for a rough colour selection as associations show.

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

PubMed

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

2017-11-01

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

Treatment effects of microimplant-aided sliding mechanics on distal retraction of posterior teeth.

PubMed

Oh, Young-Hee; Park, Hyo-Sang; Kwon, Tae-Geon

2011-04-01

Our objective was to quantify the treatment effects of microimplant-aided mechanics on group distal retraction of the posterior teeth. The pretreatment and posttreatment cephalometric radiographs and dental casts of 23 patients (mean age, 22.1 ± 5.17 years), treated with distalization of the posterior teeth against microimplant anchorage and without extraction of the premolars or other teeth except the third molars, were used. The soft-tissue, skeletal, and dental measurements in the vertical and anteroposterior dimensions were analyzed. The changes in interpremolar and intermolar widths and rotations of the molars were analyzed with dental casts. The upper and lower lips were repositioned distally. The Frankfort horizontal to mandibular plane angle was decreased in the adult group. The maxillary posterior teeth were distalized by 1.4 to 2.0 mm with approximately 3.5° of distal tipping, and the mandibular posterior teeth were also distalized by 1.6 to 2.5 mm with approximately 6.6° to 8.3° of distal tipping. The maxillary posterior teeth showed intrusion by 1 mm. There were increases in arch widths at the premolars and molars. The overall success of microimplants was 89.7%; a well-experienced clinician had a higher success rate (98%) than did novices in this sample. The mean treatment time was 20 ± 4.9 months. With microimplant-aided sliding mechanics, clinicians can distalize all posterior teeth together with less distal tipping. The technique seems effective and efficient to treat patients who have mild arch length discrepancy without extractions. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Comparison of mesiodistal tooth widths in Caucasian, African and Japanese individuals with Brazilian ancestry and normal occlusion.

PubMed

Fernandes, Thais Maria Freire; Sathler, Renata; Natalício, Gabriela Letícia; Henriques, José Fernando Castanha; Pinzan, Arnaldo

2013-01-01

To observe the presence of sexual dimorphism and compare the mesiodistal width of the teeth in Caucasian, African and Japanese individuals with Brazilian ancestry not orthodontically treated and with normal occlusion. One hundred pairs of dental casts were used. It was measured, from first molar to first molar in both arches, the teeth's mesiodistal widths, using a digital caliper. For the statistical analysis of results Kolmogorov-Smirnov, t test, ANOVA and Tukey's test (p < 0.05) were used. Sexual dimorphism occurred on the three evaluated groups, and the highest mesiodistal widths were found in males. There was statistically significant difference between racial groups in all evaluated teeth in males. However, in females, this same difference was found only on upper lateral incisor and first molar; and lower lateral incisor, canine, first premolar and first molar. Most of mesiodistal measures present particular characteristics in relation to gender, with higher values for males, and to race, with a tendency for African to present greater mesiodistal distance of the teeth, followed by Japanese and Caucasians, respectively, important for the correct diagnosis and orthodontic planning.

A new species of Hemibrycon (Characiformes, Characidae) from the upper San Juan River drainage, Pacific versant, Colombia

PubMed Central

Román-Valencia, César; Ruiz-C, Raquel I.; Taphorn, Donald C.; García-Alzate, Carlos A.

2014-01-01

Abstract Hemibrycon sanjuanensis, new species, is described from the upper San Juan River drainage, Pacific versant, Colombia. It is distinguished from Hemibrycon boquiae, Hemibrycon brevispini, Hemibrycon cairoense, Hemibrycon colombianus, Hemibrycon mikrostiktos, Hemibrycon metae, Hemibrycon palomae, Hemibrycon rafaelense and Hemibrycon tridens by the presence of a circular or oblong humeral spot that is located two scales posterior to the opercle (vs. 3–4 scales in Hemibrycon palomae, Hemibrycon rafaelense, Hemibrycon brevispini and Hemibrycon cairoense, and 0–1 scales, in Hemibrycon metae and Hemibrycon boquiae). It further differs from Hemibrycon colombianus in having a round or oblong humeral spot (vs. rectangular). It differs from Hemibrycon beni, Hemibrycon dariensis, Hemibrycon divisorensis, Hemibrycon helleri, Hemibrycon huambonicus, Hemibrycon inambari, Hemibrycon jabonero, Hemibrycon jelskii, Hemibrycon mikrostiktos, Hemibrycon polyodon, Hemibrycon quindos, Hemibrycon raqueliae, Hemibrycon santamartae, Hemibrycon surinamensis, Hemibrycon taeniurus, Hemibrycon tridens, and Hemibrycon yacopiae in having melanophores on the posterior margins of the scales along the sides of body (vs. lacking melanophores on margins of scales along entire length of the sides of body). The new species differs from all congeners mentioned above in having, among other features, six teeth in the outer premaxillary row arranged in a straight line (vs. five or fewer teeth not arranged in straight line except Hemibrycon cairoense with two to six teeth in the outer premaxillary row). PMID:25493068

Molar incisor hypomineralization: proportion and severity in primary public school children in Graz, Austria.

PubMed

Buchgraber, Barbara; Kqiku, Lumnije; Ebeleseder, Kurt A

2018-03-01

The aim of this study was to determine the proportion and severity of molar incisor hypomineralization (MIH) in primary school children in Graz (southeast of Austria). In 1111 children aged 6 to 12 years (mean age 9.0 ± 1.2), a wet examination of all teeth was performed by three trained examiners using a dental chair, optimal illumination, a dental mirror, and a dental explorer. All teeth with MIH lesions were registered so that different definitions of MIH were applicable. According to the European Academy of Pediatric Dentistry criteria that were considered valid at the time of the investigation, MIH was diagnosed when at least one first primary molar (FPM) was affected. MIH was present in 78 children (7.0%). In 64 children (5.8%), at least one molar and one incisor were affected (so-called M + IH). Additionally, in 9 children, only incisors were affected. In 7 affected children, teeth other than FPMs and incisors had MIH lesions. Almost an equal number of males (38) and females (40) were affected. The upper and lower molars were equally affected. The upper incisors were more frequently affected than the lower ones. Demarcated enamel opacities were the predominant types of defects. The proportion of MIH was 7.0% in Graz, which is similar to other comparable trials. This study has proven that MIH is an existing dental problem in Graz.

Efficacy test of a toothpaste in reducing extrinsic dental stain

NASA Astrophysics Data System (ADS)

Agustanti, A.; Ramadhani, S. A.; Adiatman, M.; Rahardjo, A.; Callea, M.; Yavuz, I.; Maharani, D. A.

2017-08-01

This clinical trial compared the external dental stain reduction achieved by tested toothpaste versus placebo in adult patients. In this double-blind, parallel, randomised clinical trial, 45 female volunteers with a mean age of 20 years old were included. All study subjects front teeth were topically applicated with Silver Diamine Fluoride (SDF) to create external dental stains. Subjects were randomized into test (n=22) and control (n=23) groups. Toothpastes were used for two days to analyse the effects of removing external stains on the labial surfaces of all anterior teeth. VITA Easyshade Advance 4.0 was used to measure dental extrinsic stains changes. The analysis showed statistically significant efficacy of the tested toothpaste in reducing external dental stain caused by SDF, comparing to the placebo toothpaste, after one and two days of usage. The tested toothpaste was effective in reducing dental stain.

Anatomoradiographic description of the teeth of pacas bred in captivity (Agouti paca, Linnaeus, 1766).

PubMed

Oliveira, F S; Canola, J C; Oliveira, P T; Pécora, J D; Capelli, A

2006-10-01

Two newborn males, two adult males 9 and 72 months old, one newborn female and two adult females of 30 and 54 months old pacas were used. Animals were radiographed on lateral recumbency, teeth were extracted and the vestibulolingual and mesiodistal lengths were achieved at the occlusal surface, besides the longitudinal length. The lower incisors presented greater length in relation to the other ones and sinuous shape; the upper incisors, relatively smaller, are practically straight. There is no canine tooth, and after a great diastema there is one premolar and three molars in each hemiarcade. In adult pacas, the enamel of incisors presents yellowish colour, mainly in the labial surface; in the premolars and molars, the enamel is present as internal sheets disposed nearly in a parallel way and in vestibulolingual direction, through practically all the dental length, which provides several joined teeth aspect.

Experimental Study on Strength Evaluation Applied for Teeth Extraction: An In Vivo Study

PubMed Central

Cicciù, Marco; Bramanti, Ennio; Signorino, Fabrizio; Cicciù, Alessandra; Sortino, Francesco

2013-01-01

Purpose: The aim of this work was to analyse all the applied movements when extracting healthy upper and lower jaw premolars for orthodontic purposes. The authors wanted to demonstrate that the different bone densities of the mandible and maxilla are not a significant parameter when related to the extraction force applied. The buccal and palatal rocking movements, plus the twisting movements were also measured in this in-vivo study during premolar extraction for orthodontic purposes. Methods: The physical strains or forces transferred onto the teeth during extraction are the following three movements: gripping, twisting, and traction. A strain measurement gauge was attached onto an ordinary dentistry plier. The strain measurement gauge was constituted with an extensimetric washer with three 45º grids. The system operation was correlated to the variation of electrical resistance. Results: The variations of resistance (∆R) and all the different forces applied to the teeth (∆V) were recorded by a computerized system. Data results were processed through Microsoft Excel. The results underlined the stress distribution on the extracted teeth during gripping, twisting and flexion. Conclusions: The obtained data showed that the strength required to effect teeth extraction is not influenced by the quality of the bone but is instead influenced by the shape of the tooth’s root. PMID:23539609

[Change in trigeminal mesencephalic neurons after teeth extraction in guinea pig].

PubMed

Kimoto, A

1993-03-01

Trigeminal mesencephalic (Mes V) neurons innervating the periodontal mechanoreceptor (PMR) are known to play an important role in controlling the bite force and jaw-movements during mastication. After teeth loss, the PMR disappears due to loss of the periodontal membrane. The present work is a study on whether cell death is induced in the Mes V neurons in association with teeth loss. The upper and lower incisors were extracted on the right side in 5 guinea pigs (extraction group) and the other 5 guinea pigs were kept intact (control group). In the extraction group, the animals were kept alive for 58-119 days after teeth extraction. Serial coronal sections (50 microns thick) were made of the midbrain and pons and stained with cresyl violet. The Mes V neurons were counted on every other section. In the caudal half of the Mes V nucleus, where the neurons innervating the PMR are reported to be located, the number of neurons was less on the right side than on the left side (P < 0.01) in the extraction group, while there was no difference between the right and left sides in the control group. We conclude that teeth extraction can induce cell death in the Mes V neurons innervating the PMR and produce a significant change in the brainstem mechanisms controlling mastication.

The CHARGE association: report of two cases.

PubMed

Venetikidou, A

1993-01-01

Although many reports of the CHARGE association appear in the literature, the dental findings were never discussed before. In this report of two cases, both patients present with delayed eruption of the permanent teeth and a remarkable similarity of the eruption pattern of the mandibular teeth. One lower permanent central incisor is congenitally missing, while the other is malformed. The lower permanent laterals of JM have erupted lingually and interfere with his speech and function of the tongue. Mandibular retrognathism is present. TM had a V-shaped constricted upper arch, which was expanded in a first phase of orthodontic intervention. Fixed appliances are the future considerations for the correction of the malocclusion.

Association between root resorption incident to orthodontic treatment and treatment factors.

PubMed

Motokawa, Masahide; Sasamoto, Tomoko; Kaku, Masato; Kawata, Toshitsugu; Matsuda, Yayoi; Terao, Akiko; Tanne, Kazuo

2012-06-01

The purpose of this study was to clarify the prevalence and degree of root resorption induced by orthodontic treatment in association with treatment factors. The files of 243 patients (72 males and 171 females) aged 9-51 years were randomly selected from subjects treated with multi-bracket appliances. The severity of root resorption was classified into five categories on radiographs taken before and after treatment. The subjects were divided into extraction (n = 113 patients, 2805 teeth) and non-extraction (n = 130 patients, 3616 teeth) groups and surgical (n = 56 patients, 1503 teeth) and non-surgical treatment (n = 187 patients, 4918 teeth) groups. These subjects were also divided into two or three groups based on the duration of multiloop edgewise archwire (MEAW) treatment, elastic use, and total treatment time: 0 month (T1; n = 184 patients, 4831 teeth), range 1-6 months (T2; n = 37 patients, 994 teeth), more than 6 months (T3; n = 22 patients, 596 teeth); range 0-6 months (n = 114 patients, 3016 teeth) more than 6 months (n = 129 patients, 3405 teeth); range 1-30 months (n = 148 patients, 3913 teeth) and more than 30 months (n = 95 patients, 2508 teeth). The prevalence of overall and severe root resorption evaluated by the number of subjects and teeth was compared with a chi-square test. A Student's t-test for unpaired data was used to determine any statistically significant differences. The prevalence of severe root resorption based on the number of teeth was significantly higher in the group with extractions (P < 0.01). Longer use of a MEAW appliance and elastics also produced a significantly higher prevalence of root resorption (P < 0.05). On the other hand, the prevalence of severe root resorption was not significantly different between the subjects treated with or without surgery, but there was a significant increase when treatment time was prolonged (P < 0.05). A significant difference was found in the amount of root movement of the upper central incisors and the distance from their root apices to the cortical bone surface (P < 0.05). These are regarded as essential factors in the onset of root resorption. These results indicate that orthodontic treatment with extractions, long-term use of a MEAW appliance and elastics, treatment time, and distance of tooth movement are risk factors for severe root resorption.

Fishes and tetrapods in the upper pennsylvanian (kasimovian) cohn coal member of the mattoon formation of illinois, United States: Systematics, paleoecology, and paleoenvironments

USGS Publications Warehouse

Carpenter, D.; Falcon-Lang, H. J.; Benton, M.J.; Nelson, W.J.

2011-01-01

A newly discovered vertebrate assemblage is reported from the Upper Pennsylvanian (mid-to upper Kasimovian) Cohn Coal Member of the Mattoon Formation of southeast Illinois, United States. Teeth, scales, and spines of xenacanth (Dicentrodus, Orthacanthus, Triodus, Xenacanthus) and euselachian (Sphenacanthus) sharks dominate the assemblage. Less common are the teeth, scales, and centra of holocephalan (Helodus) and actinopterygian fishes, together with rare tetrapod (mainly pelycosaur) phalanges and centra. The assemblage occurs within a broad, shallow channel incised into a prominent Vertisol. The channel is interpreted as having been cut during a seasonally dry glacial phase when sea level was low, but filled during a subsequent transgression triggered by deglaciation. We interpret this as a brackish water (estuarine) assemblage, based on the co-occurrence of the vertebrate material with spirorbids (putative microconchids) and paleoecological inferences gleaned from a critical analysis of the literature dealing with Pennsylvanian fish ecology. This interpretation is broadly consistent with taphonomic data and the results of 87Sr/86Sr isotope analysis of shark material. The pelycosaur material may have been reworked from the lowstand Vertisol, however, and these animals occupied dryland niches that developed during glacial phases. ?? 2011 SEPM (Society for Sedimentary Geology).

Design and finite element analysis of a novel sliding rod microscrew implantation device for mandibular prognathism

PubMed Central

Li, Yanfeng; Lv, Yuan; Lu, Yongjin; Zeng, Pan; Zeng, Xianglong; Guo, Xiaoqian; Han, Weili

2015-01-01

Tooth distalization is an effective approach for mandibular prognathism. Current distalization devices are bulky and clinically complicated. Here, we designed a novel molar distalization device by using a sliding rod and a microscrew and performed a mechanical analysis and finite element model (FEM) analysis of force distribution and displacement of the upper canine, first and second premolar and first molar. A 2D FEM was constructed using the Beam3 element and a 3D FEM was constructed of the mandibular teeth, the periodontal membrane, and the alveolar bones using the UG software. The upper first molar was divided into 12 points on the dental surface to facilitate stress analysis. Force analysis using the ANSYS WORKBECNH revealed that, both horizontally and vertically, the traction force causing distalization of the first molar decreased when the spring coil moved down the L shaped sliding rod. The 3D FEM force analysis revealed distomedial displacement of the upper first molar when the sliding rod microscrew implantation device caused distalization of the molar. These findings support further exploration for the use of the sliding rod microscrew implants as an anchorage for group distal movement of the teeth of patients with mandibular prognathism. PMID:26379860

A new species of Euprox (Cervidae, Artiodactyla) from the upper Miocene of the Linxia Basin, Gansu Province, China, with interpretation of its paleoenvironment.

PubMed

Hou, Sukuan

2015-01-16

The Linxia Basin, Gansu Province, China, is known for its abundant and well preserved fossils. Here a new species, Euprox grandis sp. nov., is established based on a skull and antlers collected from the upper Miocene Liushu Formation of the Linxia Basin. The new species is distinguishable from other Euprox species by its large body size, notably long pedicle and weak burr. The main beam and the brow tine are slightly curved both medially and backwards, and the apex of the main beam turns, curving slightly laterally. The upper cheek teeth are brachydont, with a clear central fold on the premolars and internal postprotocrista and metaconule fold on M1-M2. The cingulum is almost absent, only occasionally weakly developed at the anterior and lingual surface of the teeth. Cladistic analysis was carried out using the TNT software, and two most parsimonious trees were retained. As the strict consensus tree shows E. grandis appears to be an advanced muntiacine form, which may have a close relationship with the genus Muntiacus. The presence of E. grandis in the Linxia Basin adds new evidence to support a warm and humid environment during the late Miocene in the basin. 

Adhesives for fixed orthodontic bands.

PubMed

Millett, Declan T; Glenny, Anne-Marie; Mattick, Rye Cr; Hickman, Joy; Mandall, Nicky A

2016-10-25

Orthodontic treatment involves using fixed or removable appliances (dental braces) to correct the positions of teeth. It has been shown that the quality of treatment result obtained with fixed appliances is much better than with removable appliances. Fixed appliances are, therefore, favoured by most orthodontists for treatment. The success of a fixed orthodontic appliance depends on the metal attachments (brackets and bands) being attached securely to the teeth so that they do not become loose during treatment. Brackets are usually attached to the front and side teeth, whereas bands (metal rings that go round the teeth) are more commonly used on the back teeth (molars). A number of adhesives are available to attach bands to teeth and it is important to understand which group of adhesives bond most reliably, as well as reducing or preventing dental decay during the treatment period. To evaluate the effectiveness of the adhesives used to attach bands to teeth during fixed appliance treatment, in terms of:(1) how often the bands come off during treatment; and(2) whether they protect the banded teeth against decay during fixed appliance treatment. The following electronic databases were searched: Cochrane Oral Health's Trials Register (searched 2 June 2016), Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5) in the Cochrane Library (searched 2 June 2016), MEDLINE Ovid (1946 to 2 June 2016) and EMBASE Ovid (1980 to 2 June 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised and controlled clinical trials (RCTs and CCTs) (including split-mouth studies) of adhesives used to attach orthodontic bands to molar teeth were selected. Patients with full arch fixed orthodontic appliance(s) who had bands attached to molars were included. All review authors were involved in study selection, validity assessment and data extraction without blinding to the authors, adhesives used or results obtained. All disagreements were resolved by discussion. Five RCTs and three CCTs were identified as meeting the review's inclusion criteria. All the included trials were of split-mouth design. Four trials compared chemically cured zinc phosphate and chemically cured glass ionomer; three trials compared chemically cured glass ionomer cement with light cured compomer; one trial compared chemically cured glass ionomer with a chemically cured glass phosphonate. Data analysis was often inappropriate within the studies meeting the inclusion criteria. There is insufficient high quality evidence with regard to the most effective adhesive for attaching orthodontic bands to molar teeth. Further RCTs are required.

Polymerization shrinkage of different types of composite resins and microleakage with and without liner in class II cavities.

PubMed

Karaman, E; Ozgunaltay, G

2014-01-01

To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro. One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests. All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (p<0.05). The use of RMGIC liner with both silorane- and methacrylate-based composite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.

Healthy Dental Pulp Oxygen Saturation Rates in Subjects with Homozygous Sickle Cell Anemia: A Cross-Sectional Study Nested in a Cohort.

PubMed

Souza, Soraia de Fátima Carvalho; Thomaz, Erika Bárbara Abreu Fonseca; Costa, Cyrene Piazera Silva

2017-12-01

To compare the percentage of arterial oxygen saturation (SpO 2 ) in healthy teeth with confirmed pulp vitality between individuals with sickle cell anemia (HbSS) and normal hemoglobin A (HbAA). This is a cross-sectional study nested within a cohort. Samples (n = 2543) comprised teeth with intact crowns and pulp vitality confirmed by thermal sensitivity tests and no history of caries, periodontal disease, or dental trauma. A total of 728 teeth of 113 individuals with HbSS and 1815 teeth of 246 individuals with HbAA were evaluated. Data analysis was performed using the χ 2 and Mann-Whitney tests and Spearman correlation analysis (α = 0.05). The study groups were comparable in terms of age, race, and sex (P > .05). Subjects with HbSS exhibited lower median SpO 2 levels in the body and upper teeth, excluding canines, than subjects with HbAA (P < .05). There were no significant differences in the evaluated parameters between the 2 groups (P > .05). Compared with individuals with HbAA, those with HbSS exhibited lower SpO 2 in maxillary teeth with confirmed pulp vitality, except in the canines. There was no correlation between SpO 2 levels of the body and dental pulp in individuals with HbSS or HbAA. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Export of Ice-Cavity Water from Pine Island Ice Shelf, West Antarctica

NASA Astrophysics Data System (ADS)

Thurnherr, Andreas; Jacobs, Stanley; Dutrieux, Pierre

2013-04-01

Stability of the West Antarctic Ice Sheet is sensitive to changes in melting at the bottom of floating ice shelves that form the seaward extensions of Antarctic glaciers flowing into the ocean. Not least because observations in the cavities beneath ice shelves are difficult, heat fluxes and melt rates have been inferred from oceanographic measurements obtained near the ice edge (calving fronts). Here, we report on a set of hydrographic and velocity data collected in early 2009 near the calving front of the Amundsen Sea's fast-moving and (until recently) accelerating Pine Island Glacier and its associated ice shelf. CTD profiles collected along the southern half of the meridionally-trending ice front show clear evidence for export of ice-cavity water. That water was carried in the upper ocean along the ice front by a southward current that is possibly related to a striking clockwise gyre that dominated the (summertime) upper-ocean circulation in Pine Island Bay. Signatures of ice-cavity water appear unrelated to current direction along most of the ice front, suggesting that cross-frontal exchange is dominated by temporal variability. However, repeated hydrographic and velocity measurements in a small "ice cove" at the southern end of the calving front show a persistent strong (mean velocity peaking near 0.5 ms-1) outflow of ice-cavity water in the upper 500 m. While surface features (boils) suggested upwelling from deep below the ice shelf, vertical velocity measurements reveal 1) that the mean upwelling within the confines of the cove was too weak to feed the observed outflow, and 2) that large high-frequency internal waves dominated the vertical motion of water inside the cove. These observations indicate that water exchange between the Pine Island Ice Shelf cavity and the Amundsen sea is strongly asymmetric with weak broad inflow at depth and concentrated surface-intensified outflow of melt-laden deep water at the southern edge of the calving front. The lack of significant mean upward motion within the cove strongly suggests that the upwelling takes place within the highly fractured ice along the southern shear margin of the ice shelf. If so, the upwelling water is likely to contribute to both the volume of apparent "basal" melting and to the weakness of that shear margin.

Is extreme bite performance associated with extreme morphologies in sharks?

PubMed

Huber, Daniel R; Claes, Julien M; Mallefet, Jérôme; Herrel, Anthony

2009-01-01

As top predators in many oceanic communities, sharks are known to eat large prey and are supposedly able to generate high bite forces. This notion has, however, largely gone untested due to the experimental intractability of these animals. For those species that have been investigated, it remains unclear whether their high bite forces are simply a consequence of their large body size or the result of diet-related adaptation. As aquatic poikilotherms, sharks can grow very large, making them ideal subjects with which to investigate the effects of body size on bite force. Relative bite-force capacity is often associated with changes in head shape because taller or wider heads can, for example, accommodate larger jaw muscles. Constraints on bite force in general may also be released by changes in tooth shape. For example, more pointed teeth may allow a predator to penetrate prey more effectively than blunt, pavementlike teeth. Our analyses show that large sharks do not bite hard for their body size, but they generally have larger heads. Head width is the best predictor of bite force across the species included in our study as indicated by a multiple regression model. Contrary to our predictions, sharks with relatively high bite forces for their body size also have relatively more pointed teeth at the front of the tooth row. Moreover, species including hard prey in their diet are characterized by high bite forces and narrow and pointed teeth at the jaw symphysis.

Rapid Palatal Expansion in the absence of posterior cross-bite to intercept maxillary incisor crowding in the mixed dentition: a CBCT evaluation of spontaneous changes of untouched permanent molars.

PubMed

Rosa, M; Lucchi, P; Manti, G; Caprioglio, A

2016-12-01

The aim of this study was to investigate the reaction of untouched permanent molars following RPE, anchored on deciduous teeth in the early mixed dentition, aimed to solve maxillary anterior crowding in the absence of posterior cross-bite. A prospective clinical trial comprised 35 consecutive patients (20 males and 15 females) treated by the same orthodontist (MR). All patients showed crowding of the upper permanent incisors in the early mixed dentition in the absence of posterior cross-bite. RPE was anchored on second deciduous molars and on the deciduous canines. CBCT was taken before and after the removal of the RPE appliance. The transverse linear changes in width and the variation in the torque of the permanent molars were measured in the coronal plane. Relief of incisor crowding was found in all patients. The transverse width between permanent molars increased significantly. The apices of the upper permanent molars spontaneously expanded more than the crowns, while the opposite happened on the lower permanent molars. Moreover, the untouched upper permanent molars spontaneously uprighted palatally, while the lower permanent molars spontaneously uprighted buccally. The variation in the torque of the permanent molars mirrored transverse normal growth. In the early mixed dentition and in the absence of posterior cross-bite, it is possible to expand transversally the palate while uprighting the upper permanent molars in the opposite direction. RPE anchored on the deciduous teeth in the early mixed dentition, in the absence of posterior cross-bite, provides an "anticipation of transverse growth" and could be indicated to expand the anterior portion of the maxillary arch perimeter to solve upper incisor crowding.

Article of Clothing for Storing and Deploying a Scarf

NASA Technical Reports Server (NTRS)

Romero, Robert (Inventor)

2015-01-01

A clothing article surrounds a wearer's upper torso. The article includes connected front portion, a collar. A sleeve is formed in the front portion. A jacket, and coat with an attachable/detachable scarf will be folded and stored in the inter portion of the front side of the collar area with elastic at each end and Velcro onto the inner portion of your collar, therefore eliminating the lost of them by any consumers, and especially children. A sleeve like collar attached to the coat and jacket for storing a scarf and making it easily deployable while in use.

Upper-limb biomechanical analysis of wheelchair transfer techniques in two toilet configurations.

PubMed

Tsai, Chung-Ying; Boninger, Michael L; Bass, Sarah R; Koontz, Alicia M

2018-06-01

Using proper technique is important for minimizing upper limb kinetics during wheelchair transfers. The objective of the study was to 1) evaluate the transfer techniques used during toilet transfers and 2) determine the impact of technique on upper limb joint loading for two different toilet configurations. Twenty-six manual wheelchair users (23 men and 3 women) performed transfers in a side and front wheelchair-toilet orientation while their habitual transfer techniques were evaluated using the Transfer Assessment Instrument. A motion analysis system and force sensors were used to record biomechanical data during the transfers. More than 20% of the participants failed to complete five transfer skills in the side setup compared to three skills in the front setup. Higher quality skills overall were associated with lower peak forces and moments in both toilet configurations (-0.68 < r < -0.40, p < 0.05). In the side setup, participants who properly placed their hands in a stable position and used proper leading handgrips had lower shoulder resultant joint forces and moments than participants who did not perform these skills correctly (p ≤ 0.04). In the front setup, positioning the wheelchair within three inches of the transfer target was associated with reduced peak trailing forces and moments across all three upper limb joints (p = 0.02). Transfer skills training, making toilet seats level with the wheelchair seat, positioning the wheelchair closer to the toilet and mounting grab bars in a more ideal location for persons who do sitting pivot transfers may facilitate better quality toilet transfers. Published by Elsevier Ltd.

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae) from the Late Cretaceous (Santonian-Campanian) of Alabama, USA

PubMed Central

Ehret, Dana J.

2018-01-01

Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto) teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843), a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s.) taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region. PMID:29333348

[Experience of systematization on the treatment of patients with upper jaws fractures, during the period 1991-2000].

PubMed

Khinkov, D

2005-01-01

A retrospecive analysis was done of the 128 patients with fractures in a upper jaw, treated during the period 1991-2000. The treatment of the patients with partial fractures in a alveolar part of maxilla and frontal wall of maxillary sinus, consist of debridement on the open wound, primery stiched and stabilization by arch bar of perspective teeth. In the cases with fractures of tuber maxilla and opening of maxillary sinus they tray to clouse it by Rhermann technique, with or without radical antrothomy by Caldwell-Luc technique. On the patients by total upper jaw fractures they try lead by princip of duble stage fixation: from one side-of intact upper bone structures and the other side-on a mandible. On the cases of upper jaw fractures, combine with barain traums. was treated conservativly - the specialize treatment of facial injures was postpoun until stabilization of brain status.

14. Photocopy of drawing dated January 20, 1958, FRONT FRAMING, ...

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

14. Photocopy of drawing dated January 20, 1958, FRONT FRAMING, REHABILITATION OF PIERSHED AT FOOT OF 29TH ST. City of New York Department of Marine and Aviation, Contract 3049, Drawing 5. (On file, City of New York Department of Ports and Trade). - South Brooklyn Freight Terminal, 29th Street Pier, Opposite end of Twenty-ninth Street on upper New York Bay, Brooklyn, Kings County, NY

Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion.

PubMed

Bhatia, S; Jayan, B; Chopra, S S

2016-12-01

To test the hypothesis that the retraction of anterior teeth has no effect on the dimensions of pharyngeal airway and to evaluate the retraction of anterior teeth on each parameter of pharyngeal airway. Twenty-two adult patients of Class I bimaxillary protrusion requiring first premolar extractions with maximum anchorage requirements were selected. The pharyngeal airway and dentofacial parameters of the patients were compared using pre- and post-treatment lateral cephalograms with the help of Student's paired t -test ( P  < 0.05). The relationship between airway size and dentofacial parameters was also evaluated using Pearson correlation coefficient. The upper and lower lips were retracted by 2.25 and 5.4 mm after retraction of the incisors. The tips of upper and lower incisors were retracted by 7.75 and 7.15 mm, respectively. There was a statistically significant decrease in SPP-SPPW ( P  < 0.05), U-MPW ( P  < 0.001), TB-TPPW ( P  < 0.001), and change in HRGN ( P  < 0.01). A significant correlation was observed between the amount of retraction of lower incisor and decrease in the pharyngeal airway posterior to soft palate ( r  = 0.102), tongue ( r  = 0.322), and change in HRGN ( r  = 0.265). The size of the pharyngeal (velopharyngeal and glossopharyngeal) airway reduced and hyoid bone position changed after retraction of the incisors in extraction space in bimaxillary protrusive adult patients.

Multimodal registration of three-dimensional maxillodental cone beam CT and photogrammetry data over time.

PubMed

Bolandzadeh, N; Bischof, W; Flores-Mir, C; Boulanger, P

2013-01-01

In recent years, one of the foci of orthodontics has been on systems for the evaluation of treatment results and the tracking of tissue variations over time. This can be accomplished through analysing three-dimensional orthodontic images obtained before and after the treatments. Since complementary information is achieved by integrating multiple imaging modalities, cone beam CT (CBCT) and stereophotogrammetry technologies are used in this study to develop a method for tracking bone, teeth and facial soft-tissue variations over time. We propose a two-phase procedure of multimodal (Phase 1) and multitemporal (Phase 2) registration which aligns images taken from the same patient by different imaging modalities and at different times. Extrinsic (for Phase 1) and intrinsic (for Phase 2) landmark-based registration methods are employed as an initiation for a robust iterative closest points algorithm. Since the mandible moves independently of the upper skull, the registration procedure is applied separately on the mandible and the upper skull. The results show that the signed error distributions of both mandible and skull registrations follow a mixture of two Gaussian distributions, corresponding to alignment errors (due to our method) and temporal change over time. We suggest that the large values among the total registration errors correspond to the temporal change resulting from (1) the effect of treatment (i.e. the orthodontic changes of teeth positions); (2) the biological changes such as teeth growth over time, especially for teenagers; and (3) the segmentation procedure and CBCT precision change over time.

Periapical Status and Quality of Root Canal Fillings in a Moroccan Subpopulation

PubMed Central

El Merini, Hafsa; Lamzawaq, Amine; Hamza, Mouna

2017-01-01

Aim The aim of the study was to assess the prevalence of apical periodontitis (AP) and quality of root canal fillings in an adult Moroccan subpopulation. Methods In the study 508 patients were included, attending the Conservative Dentistry Clinic at the Faculty of Dentistry of Casablanca. 508 panoramic and 709 periapical radiographs were observed. The periapical status of all teeth (with the exception of third molars) was examined according to Ørstavik's periapical index. The statistical analysis was performed with the software Epi Info Version 6.04dfr, April 2001. Results A total of 12719 teeth were examined. 45.3% of patients had apical periodontitis. 4.2% of teeth were treated endodontically and 70.4% of these treatments were inadequate. 91,5% with inadequate endodontic treatment presented apical periodontitis, while only 8,2% with adequate endodontic treatment had apical periodontitis. The lower molars and the upper premolars were the most affected teeth. The presence of apical periodontitis was correlated significantly with insufficient root canal fillings (p < 0.05). Conclusions The present study found a high prevalence of apical periodontitis in this Moroccan population. Inadequate root canal fillings were associated with an increased prevalence of apical periodontitis. PMID:28713425

The effect of luting media on the fracture resistance of a flame sprayed all-ceramic crown.

PubMed

Casson, A M; Glyn Jones, J C; Youngson, C C; Wood, D J

2001-11-01

This in vitro study investigated the effect of selected luting media on the fracture resistance of a flame-sprayed all-ceramic crown. Three groups of 10 human upper premolar teeth were prepared for crowning using a standardised technique. Flame sprayed crowns were fabricated and cemented onto the preparations using zinc phosphate (ZPC), glass polyalkenoate (GPC) or composite luting cement (CLC). During crown seating, a pressure perfusion system simulated pulpal fluid outflow equivalent to 300mm of H2O. Compressive fracture resistance was determined for each group using a Universal Testing Machine with a crosshead speed of 1mm min(-1). A group of unrestored teeth acted as a control. The fracture resistance of the groups ranked as follows: ZPC>CLC>GPC=unrestored teeth. The difference between the fracture resistance of ZPC and CLC groups and the control group was statistically significant. The mode of fracture between the luted crowns and natural crowns was markedly different. When tested in compression, a new, flame-sprayed all-ceramic crown, when luted in place using ZPC, GPC or CLC, could produce strengths comparable to or greater than natural unrestored teeth. The luting agent used significantly affected the recorded fracture loads.

Bond strength of stainless steel orthodontic brackets bonded to prefabricated acrylic teeth.

PubMed

Wan Abdul Razak, Wan Salbiah; Sherriff, Martyn; Bister, Dirk; Seehra, Jadbinder

2017-06-01

The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Šidak's adjustment) were undertaken. The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.

Evidence of a specialized feeding niche in a Late Triassic ray-finned fish: evolution of multidenticulate teeth and benthic scraping in †Hemicalypterus.

PubMed

Gibson, Sarah Z

2015-04-01

Fishes have evolved to exploit multiple ecological niches. Extant fishes in both marine (e.g., rabbitfishes, surgeonfishes) and freshwater systems (e.g., haplochromine cichlids, characiforms) have evolved specialized, scoop-like, multidenticulate teeth for benthic scraping, feeding primarily on algae. Here, I report evidence of the oldest example of specialized multidenticulate dentition in a ray-finned fish, †Hemicalypterus weiri, from the Upper Triassic Chinle Formation of southeastern Utah (∼210-205 Ma), USA. †H. weiri is a lower actinopterygian species that is phylogenetically remote from modern fishes, and has evolved specialized teeth that converge with those of several living teleost fishes (e.g., characiforms, cichlids, acanthurids, siganids), with a likely function of these teeth being to scrape algae off a rock substrate. This finding contradicts previously held notions that fishes with multicuspid, scoop-like dentition were restricted to teleosts, and indicates that ray-finned fishes were diversifying into different trophic niches and exploring different modes of feeding earlier in their history than previously thought, fundamentally altering our perceptions of the ecological roles of fishes during the Mesozoic.

Arresting rampant dental caries with silver diamine fluoride in a young teenager suffering from chronic oral graft versus host disease post-bone marrow transplantation: a case report.

PubMed

Chu, Chun-Hung; Lee, Angeline Hui-Cheng; Zheng, Liwu; Mei, May Lei; Chan, Godfrey Chi-Fung

2014-01-03

Rampant caries is an advanced and severe dental disease that affects multiple teeth. This case describes the management of rampant caries in a young teenager suffering from chronic oral graft versus host disease after allogeneic bone marrow transplantation. A 14-year-old Chinese boy suffering from β-thalassemia major was referred to the dental clinic for the management of rampant dental caries. An oral examination revealed pale conjunctiva, bruising of lips, and depapillation of tongue indicating an underlying condition of anemia. The poor oral condition due to topical and systemic immunosuppressants was seriously aggravated, and rampant caries developed rapidly, affecting all newly erupted, permanent teeth. The teeth were hypersensitive and halitosis was apparent. Strategies for oral health education and diet modification were given to the patient. Xylitol chewing gum was used to stimulate saliva flow to promote remineralization of teeth. Silver diamine fluoride was topically applied to arrest rampant caries and to relieve pain from hypersensitivity. Carious teeth with pulpal involvement were endodontically treated. Stainless steel crowns were provided on molars to restore chewing function, and polycarbonate crowns were placed on premolars, upper canines and incisors. This case report demonstrates success in treating a young teenager with severe rampant dental decay by contemporary caries control and preventive strategy.

Construction of three-dimensional tooth model by micro-computed tomography and application for data sharing.

PubMed

Kato, A; Ohno, N

2009-03-01

The study of dental morphology is essential in terms of phylogeny. Advances in three-dimensional (3D) measurement devices have enabled us to make 3D images of teeth without destruction of samples. However, raw fundamental data on tooth shape requires complex equipment and techniques. An online database of 3D teeth models is therefore indispensable. We aimed to explore the basic methodology for constructing 3D teeth models, with application for data sharing. Geometric information on the human permanent upper left incisor was obtained using micro-computed tomography (micro-CT). Enamel, dentine, and pulp were segmented by thresholding of different gray-scale intensities. Segmented data were separately exported in STereo-Lithography Interface Format (STL). STL data were converted to Wavefront OBJ (OBJect), as many 3D computer graphics programs support the Wavefront OBJ format. Data were also applied to Quick Time Virtual Reality (QTVR) format, which allows the image to be viewed from any direction. In addition to Wavefront OBJ and QTVR data, the original CT series were provided as 16-bit Tag Image File Format (TIFF) images on the website. In conclusion, 3D teeth models were constructed in general-purpose data formats, using micro-CT and commercially available programs. Teeth models that can be used widely would benefit all those who study dental morphology.

Geochemistry of fluoride in the Black Creek aquifer system of Horry and Georgetown Counties, South Carolina--and its physiological implications

USGS Publications Warehouse

Zack, Allen L.

1980-01-01

High concentrations of fluoride in ground-water supplies in certain areas of Horry and Georgetown Counties, S.C., have been the cause of dental fluorosis (tooth mottling) among persons who have lived in these areas and have ingested the water as children. Geochemical evidence and laboratory experiments demonstrate that fluorapatite in the form of fossil shark teeth is the source of fluoride, and that the fluoride ions are liberated to the ground-water system through anion exchange, rather than by dissolution. Calcite-cemented quartz sand in the upper third of the Black Creek Formation of Late Cretaceous age contains the fossil shark teeth. As ground water progresses downdip, the calcite matrix dissolves and hydrolyzes, releasing bicarbonate, hydroxyl, and calcium ions. The calcium ions are immediately exchanged for sodium ions adsorbed on sodium-rich clays, and the bicarbonate ions accumulate. As the shark teeth are exposed, the hydroxyl ions in solution exchange with fluoride ions on fluorapatite surfaces. Experiments using fossil shark teeth show that sodium chloride in solution inhibits the rate of exchange of fluoride ions from tooth surfaces for hydroxyl ions in solution. The amount of fluoride removed from water and exchanged for hydroxyl ions in the presence of pure hydroxylapatite (hog teeth) was greater in saline water than in freshwater.

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, T.R.

1983-07-05

A method and a cutter are disclosed for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head has a hollow body with a generally circular base and sloping upper surface. A hollow shaft extends from the hollow body. Cutter teeth are mounted on the upper surface of the body and relatively small holes are formed in the body between the cutter teeth. Relatively large peripheral flutes around the body allow material to drop below the drill head. A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale. 4 figs.

La formation de l'inkisi (Supergroupe ouest-congolien) en Afrique centrale (Congo et Bas-Zaïre): un delta d'âge Paléozoïque comblant un bassin en extension

NASA Astrophysics Data System (ADS)

Alvarez, Philippe; Maurin, Jean-Christophe; Vicat, Jean-Paul

1995-02-01

The Inkisi Formation (West Congolian Supergroup) corresponds to a large deltaic body, which extends through Congo, Lower Zaire and Angola. In the Congo and Lower Zaire areas, the lower part of this formation is characterized by a fluvial conglomerate with elliptic pebbles. The red arkosic, channelized series from the Brazzaville-Kinshasa area involves delta plain distributary channels and delta front sequences. The transport direction of continental material is from north to south and the source area is the Chaillu basement. Glacial quartzitic pebbles are probably reworked from the fluvio-lacustrine Upper Diamictite Formation. The classical subdivisions of the Inkisi Formation - basal conglomerate (I 0), Lower part (I 1) and Upper part (I 2) - are not used. These subdivisions correspond to a fluvial conglomerate and to delta front and delta plain facies. The coastal onlap progressively covered the conglomerate and the distributary channels in the delta plain was prograding onto the delta front. The prodelta sequence could correspond to the Upper level of the Mpioka molassic Formation. The Inkisi delta was on the northern edge of an extensional basin controlled by NE-SW normal faults. The extension phase is dearly post Pan-African and occurred during the Palaeozoic, probably in relation to the Permian Karoo phase, and is also known in Angola.

Esthetic Rehabilitation of Anterior Teeth with Laminates Composite Veneers

PubMed Central

Riva, Giancarlo

2014-01-01

No- or minimal-preparation veneers associated with enamel preservation offer predictable results in esthetic dentistry; indirect additive anterior composite restorations represent a quick, minimally invasive, inexpensive, and repairable option for a smile enhancement treatment plan. Current laboratory techniques associated with a strict clinical protocol satisfy patients' restorative and esthetic needs. The case report presented describes minimal invasive treatment of four upper incisors with laminate nanohybrid resin composite veneers. A step-by-step protocol is proposed for diagnostic evaluation, mock-up fabrication and trial, teeth preparation and impression, and adhesive cementation. The resolution of initial esthetic issues, patient satisfaction, and nice integration of indirect restorations confirmed the success of this anterior dentition rehabilitation. PMID:25013730

Quantification of the amount of dental material removed by selective grinding in wax dentures with photogrammetric measurements.

PubMed

Ravasini, Francesco; Fornari, Matteo; Bonanini, Mauro

2016-12-01

The use of photogrammetry may be a new method to quantify the amount of artificial dental material removed from the surface of each teeth during the grind procedure (SG). SG is necessary in each denture to reach a correct occlusion. It consists in a refine action on the prosthesis teeth's surface using milling machine tools, aimed to remove the interferences (pre-contacts) between upper and lower teeth during chewing. This measure is achieved after a comparison between pre and post-grinding 3D models. This new application could be of interest for both dentists and dental technicians because it could be used to evaluate, with a accurate numerical description, the action applied on teeth surfaces during the grinding process. Furthermore, results of the analysis could have some value for the dental industry, since the use of photogrammetry can improve the process, reducing costs during the design of artificial teeth and eventually this method could be used as a teaching tool both for dental and "dental technician" high school students. The purpose of this work is to measure the thickness of the artificial enamel removed during grinding phases. Usually, the dental technician adjusts the dental plate on the mount of the patient following the traditional method, without a quantitative evaluation of the material removed. The photogrammetric method (PM) proposed here allows to measure the amount of material removed during the grinding process. This measure is achieved after a comparison between pre and post-grinding 3D models. Under control of three teachers (experts of dentures performed according to the Gerber method) ten complete dentures arrangements (upper and inferior arches) performed by dental students at the Prosthodontic Department of the University of Parma, Italy were analyzed with PM before and after SG. The average thickness variation between the pre and post-grinding dentures is within the range of 0.1÷0.4 mm. For the upper arches, the mean value of the SG process is 223 µm while for the inferior arches is 240 µm. Results show that the most important grind process in all models appear in correspondence of cusps, with values up to 1660 µm. On the other hand, in correspondence of the fossae the results show a moderate grind action: the value is around 200-300 µm. Conversely to guidelines thought to students: cusps undergo a greater grinding process than fossae, consequently cusps should be revisioned at least on their technical and morphological aspects. The average thickness variation between the pre and post-grinding dentures is within the range of 0.1÷0.4 mm, this mean an equal value loss of vertical dimension. Furthermore, the knowledge of the gauge material removed during the SG could be useful for dental industries, giving important information, that could be considered for project and design of artificial teeth. The FM implemented in this article has given satisfactory preliminary results, showing good accuracy, low costs and high versatility. It is necessary to highlight that this is an experimental method and that the present analysis is a pilot study that needs further evaluation. Nevertheless results obtained could be of some value for medical companies, in order to improve the artificial teeth's design and project. Moreover, such a method may serve as educational tool for dental students.

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. ...

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

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. THIS ORE BIN WAS ADDED IN THE LATE 1930'S. IT IS TRAPAZOIDAL IN SHAPE, WIDER AT THE REAR THAN THE FRONT, AND DIVIDED INTO THREE BINS, EACH WITH ITS OWN CONTROL DOOR (SEE CA-290-15). - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

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

PubMed Central

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

2009-01-01

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

Angular momentum conservation law in light-front quantum field theory

DOE PAGES

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

2017-03-31

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

Angular momentum conservation law in light-front quantum field theory

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

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

Angular momentum conservation law in light-front quantum field theory

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

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QEDmore » and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less

Unique method of tooth replacement in durophagous placodont marine reptiles, with new data on the dentition of Chinese taxa

PubMed Central

Neenan, James M; Li, Chun; Rieppel, Olivier; Bernardini, Federico; Tuniz, Claudio; Muscio, Giuseppe; Scheyer, Torsten M

2014-01-01

The placodonts of the Triassic period (˜252–201 mya) represent one of the earliest and most extreme specialisations to a durophagous diet of any known reptile group. Exceptionally enlarged crushing tooth plates on the maxilla, dentary and palatine cooperated to form functional crushing areas in the buccal cavity. However, the extreme size of these teeth, combined with the unusual way they occluded, constrained how replacement occurred. Using an extensive micro-computed tomographic dataset of 11 specimens that span all geographic regions and placodont morphotypes, tooth replacement patterns were investigated. In addition, the previously undescribed dental morphologies and formulae of Chinese taxa are described for the first time and incorporated into the analysis. Placodonts have a unique tooth replacement pattern and results follow a phylogenetic trend. The plesiomorphic Placodus species show many replacement teeth at various stages of growth, with little or no discernible pattern. On the other hand, the more derived cyamodontoids tend to have fewer replacement teeth growing at any one time, replacing teeth unilaterally and/or in functional units, thus maintaining at least one functional crushing area at all times. The highly derived placochelyids have fewer teeth and, as a result, only have one or two replacement teeth in the upper jaw. This supports previous suggestions that these taxa had an alternative diet to other placodonts. Importantly, all specimens show at least one replacement tooth growing at the most posterior palatine tooth plates, indicating increased wear at this point and thus the most efficient functional crushing area. PMID:24517163

Factors influencing treatment decision-making for maintaining or extracting compromised teeth.

PubMed

Lang-Hua, Bich Hue; McGrath, Colman P J; Lo, Edward C M; Lang, Niklaus P

2014-01-01

To evaluate treatment decision-making with respect to maintaining periodontally compromised teeth among dentists with or without postgraduate qualifications in implant dentistry. A series of patient scenarios with varying degrees of periodontal disease levels was presented to dental practitioners. Practitioners' decision-making outcome was determined, and intention to retain the compromised teeth was analyzed in bivariate and regression analyses (accounting for postgraduate implant training, gender, years in dental practice, and implant placement experience). This study involved 30 dental practitioners with postgraduate implant qualifications (GDPP), 33 dental practitioners without postgraduate implant qualifications (GDP), and 27 practitioners undergoing training for postgraduate implant qualifications (GDPT). Variations in treatment decision-making were evident between the three groups. Differences in treatment approaches to retaining compromised teeth were apparent. Furthermore, variations in rehabilitation of extracted scenarios existed in terms of use of implant and number of implants need for rehabilitation. Accounting for dentist and practice factors in regression analyses, GDPP/GDPT were three times as likely to retain periodontally compromised upper molar, with or without pain, compared to GDP (without pain OR 3.10, 95%CI 1.04, 10.62 P = 0.04; with pain OR 3.08, 95%CI 1.09, 8.14 P = 0.03). Variations in treatment decision-making with respect to retaining periodontally compromised teeth exist between dental practitioners with and those without postgraduate training in implant dentistry. Furthermore differences in management approaches in how they would retain the teeth or rehabilitate the dental arch were apparent. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Damping ratio analysis of tooth stability under various simulated degrees of vertical alveolar bone loss and different root types.

PubMed

Ho, Kuo-Ning; Lee, Sheng-Yang; Huang, Haw-Ming

2017-08-03

The purpose of this study was to evaluate the feasibility of using damping ratio (DR) analysis combined with resonance frequency (RF) and periotest (PTV) analyses to provide additional information about natural tooth stability under various simulated degrees of alveolar vertical bone loss and various root types. Three experimental tooth models, including upper central incisor, upper first premolar, and upper first molar were fabricated using Ti6Al4V alloy. In the tooth models, the periodontal ligament and alveolar bone were simulated using a soft lining material and gypsum, respectively. Various degrees of vertical bone loss were simulated by decreasing the surrounding bone level apically from the cementoenamel junction in 2-mm steps incrementally downward for 10 mm. A commercially available RF analyzer was used to measure the RF and DR of impulse-forced vibrations on the tooth models. The results showed that DRs increased as alveolar vertical bone height decreased and had high coefficients of determination in the linear regression analysis. The damping ratio of the central incisor model without a simulated periodontal ligament were 11.95 ± 1.92 and 27.50 ± 0.67% respectively when their bone levels were set at 2 and 10 mm apically from the cementoenamel junction. These values significantly changed to 28.85 ± 2.54% (p = 0.000) and 51.25 ± 4.78% (p = 0.003) when the tooth model was covered with simulated periodontal ligament. Moreover, teeth with different root types showed different DR and RF patterns. Teeth with multiple roots had lower DRs than teeth with single roots. Damping ratio analysis combined with PTV and RF analysis provides more useful information on the assessment of changes in vertical alveolar bone loss than PTV or RF analysis alone.

[Combined orthodontic-orthoganthic surgery to treat asymmetric mandibular excess malocclusions].

PubMed

Li, Xiao-Bing; Chen, Song; Chen, Yang-Xi; Li, Jun

2005-06-01

To discuss the skeletal and dentoalveolar characteristics of asymmetric mandibular excess malocclusions and to discuss the procedures of combined orthodontic-orthonganthic surgery treatments of asymmetric mandibular excess malocclusions. 25 cases treated by combined orthodontic-orthognathic surgery treatments were reviewed to find out the specialties of this kind of therapy. The asymmetric of mandible presents anterior and posterior teeth tipped both sagitally and horizontally, as well as upper and lower jaws incompatibility. The pre-surgical orthodontic treatments included decomposition of anterior and posterior teeth, leveling and aligning the teeth etc. The post-surgical orthodontic treatments were to detail the occlusions. The patients all got functional and aesthetic good results after the combined orthodontic-orthognathic surgery treatments. The asymmetric mandibular excess affects the harmony of the face badly, and the correction of it must be carried out by the combined orthodontic-orthognathic surgery treatments. The pre- and post-surgical orthodontic treatments are the key stages to make the skeletal corrections stable.

Orthodontic treatment of a patient with unerupted maxillary central and lateral incisors and canine: a case report.

PubMed

Sabuncuoğlu, Fidan Alakuş; Olmez, Hüseyin

2012-05-01

The aim of this case report was to describe the orthodontic and periodontal management of a patient with three impacted anterior teeth. An 18-year-old female with Class I crowding on a Class I skeletal base presented with the chief complaint of an unaesthetic smile. Clinical examination revealed an impacted upper right permanent canine (13), lateral (12) and central incisor (11), a retained deciduous incisor and moderate crowding in the lower arch. The impacted teeth were surgically exposed (closed exposure) and aligned with fixed appliances. The 12 was extracted due to root resorption and 44 extracted to resolve the lower arch crowding. A fraenectomy and gingival recontouring were required. Orthodontic treatment resulted in improved overjet, overbite and an acceptable facial profile. The patient reported improved self esteem. While impacted anterior teeth are a clinical challenge, their surgical exposure, in combination with fixed appliances, is a conservative treatment plan which is not without complications.

A combined periodontal - prosthetic treatment approach to manage unusual gingival visibility in resting lip position and inversely inclined upper anterior teeth: a case report with discussion.

PubMed

Biniraj, K R; Janardhanan, Mahija; Sunil, M M; Sagir, Mohammed; Hariprasad, A; Paul, Tony P; Emmatty, Rishi

2015-03-01

Excessive gingival visibility during smile is a common esthetic complaint in dentistry, but excessive gingival visibility in resting lip position is relatively uncommon condition. Several exclusive radical to conservative surgical treatment or its combination with orthodontic therapy to treat this condition are within the reach of every patient nowadays. A case report of an excessive gingival visibility because of altered passive eruption along with inversely inclined maxillary anterior teeth is presented here. A relatively simple treatment approach combining periodontal and restorative therapy is used here to achieve the desirable aesthetic results. The gingival exposure resulting from altered passive eruption was completely managed by a gingivectomy, but the inclined appearance of teeth was still an aesthetic complaint. After complete healing of gingivectomy surgery, appropriately designed crowns were given to rectify the inversely inclined appearance. A complete rehabilitation of patient's smile could be achieved, the case was followed up for 3 years and the condition was found satisfactory.

A new middle eocene whale (Mammalia: Cetacea: Archaeoceti) and associated biota from Georgia

USGS Publications Warehouse

Hulbert, R.C.; Petkewich, R.M.; Bishop, G.A.; Bukry, D.; Aleshire, D.P.

1998-01-01

A shallow-marine fossil biota was recovered from the Blue Bluff unit (formerly part of the McBean Formation) in the Upper Coastal Plain of eastern Georgia. Biochronologically significant mollusks (e.g., Turritella nasuta, Cubitostrea sellaeformis, Pteropsella lapidosa) and calcareous nannoplankton (e.g., Chiasmolithus solitus, Reticulofenestra umbilica, Cribocentrum reticulatum) indicate a latest Lutetian-earliest Bartonian age, or about 40 to 41 Ma. Georgiacetus vogtlensis new genus and species is described from a well-preserved, partial skeleton. Georgiacetus is the oldest known whale with a true pterygoid sinus fossa in its basicranium and a pelvis that did not articulate directly with the sacral vertebrae, two features whose acquisitions were important steps toward adaptation to a fully marine existence. The posterior four cheek teeth of G. vogtlensis form a series of carnassial-like shearing blades. These teeth also bear small, blunt accessory cusps, which are regarded as being homologous with the larger, sharper accessory cusps of basilosaurid cheek teeth.

Rigorous results for the minimal speed of Kolmogorov-Petrovskii-Piscounov monotonic fronts with a cutoffa)

NASA Astrophysics Data System (ADS)

Benguria, Rafael D.; Depassier, M. Cristina; Loss, Michael

2012-12-01

We study the effect of a cutoff on the speed of pulled fronts of the one-dimensional reaction diffusion equation. To accomplish this, we first use variational techniques to prove the existence of a heteroclinic orbit in phase space for traveling wave solutions of the corresponding reaction diffusion equation under conditions that include discontinuous reaction profiles. This existence result allows us to prove rigorous upper and lower bounds on the minimal speed of monotonic fronts in terms of the cut-off parameter ɛ. From these bounds we estimate the range of validity of the Brunet-Derrida formula for a general class of reaction terms.

Effect of unilateral extraction of molar teeth on suprahyoid muscles: macroscopic and ultrastructural aspects.

PubMed

Iyomasa, Mamie Mizusaki; Issa, João Paulo Mardegan; Siéssere, Selma; Regalo, Simone Cecílio Hallak; Watanabe, Ii-sei

2008-12-01

Anatomical and physiologic components are parts of the stomatognathic system and their interaction results in integrated functional activities. Important alterations in the masticatory system originated by dental loss affect the bone, oral mucosa and muscular function. Dental arch structures specifically designed to receive and expose teeth allow performance of their functions. But the distinction between bony and soft tissues is lost when teeth are removed since there is not a specific function to be completed. The aim of this study was to evaluate the macroscopic and ultrastructural effects of the unilateral extraction of molar teeth on the suprahyoid muscles function, using twenty young male gerbils (Meriones unguiculatus) as the experimental animal model. They were divided in experimental malocclusion (n=10) and control (n=10) groups. The experimental malocclusion group was submitted to exodontia of the left upper molars and the control group was not submitted to this procedure and served as sham-operated. For macroscopic analysis of the suprahyoid muscle, the skin was uplifted and the muscles dissected individually and removed for weight analysis according to Scherle method. The electron microscopy analysis was made in ultra thin sections of small suprahyoid muscle fragments from the experimental and control groups, examined in a Jeol 1010, 880 Kv transmission electron microscope. Several micrographs at magnifications of 3000x, 6000x, 30,000x were randomly selected for the qualitative analysis of the muscle fiber ultrastructures. Sixty days after the induced unilateral occlusal alteration no macroscopic morphologic changes was detected in the suprahyoid muscles and the muscle volume differences between the right and left sides and between groups were not significant. However, in the ultrastructural analysis suprahyoid muscles showed characteristics of specific adaptation to the unilateral occlusal alteration, by the reduced density of subsarcolemmal mitochondria and the shorter and less numerous ramifications in intermyofibrilar mitochondria localized between electronlucid myofibrils. It is concluded that unilateral exodontia of all the upper left molars affect the ultrastructural morphology of suprahyoid muscle fibers.

Evaluation of a technique for color correction in restoring anterior teeth.

PubMed

Rauber, Gabrielle Branco; Bernardon, Jussara Karina; Vieira, Luiz Clovis Cardoso; Baratieri, Luiz Narciso

2017-09-01

This study aimed to evaluate the ability of the proposed technique in producing restorations that exhibit mimesis with tooth structure and to define a restorative clinical protocol. For this study a typodont was used. The right upper central incisor with Class IV lesion was restored with the layering technique (reference tooth, RT). For the left upper central incisor with Class IV lesion, six teeth were restored monochromatically (test teeth, TT), using DA3.5 (n = 3) and DA4 (n = 3) composite resins-resulting in six unsatisfactory color restorations. TT were divided into six groups depending on the color of unsatisfactory restoration and preparation depth. First, a preparation was realized on the labial surface with 0.5 mm, 0.7 mm or 1.0 mm of depth. A second preparation was then performed to reproduce the dentinal mamelons. Next, adhesive procedures were performed and the teeth restored. Opaque halo, opalescent halo and vestibular enamel were then reproduced by the addition of different composite resins. The RT and TT were photographed side by side in typodont to obtain six photographic prints. The photographs of the groups were subjected to visual evaluation by 120 volunteers via a questionnaire. Data were analyzed by the prevalence of answers, and Chi-square test was used to investigate the association between variables at .05 significance. Furthermore, ΔE of groups was evaluated in comparison RT. The results demonstrated that the moderate intensity restorations (DA3.5) with depths of 0.5 mm and 0.7 mm had the highest prevalence of acceptance. For severe intensity restorations (DA4), the preparation depth of 1.0 mm obtained better acceptance. The technique was able to modify the final color of Class IV restorations, producing satisfactory color restorations. This technique can be used for color correction in cases of Class IV restorations, in situations where there is no time for immediate layered restoration, and as a restorative technique. © 2017 Wiley Periodicals, Inc.

The influence of passenger car front shape on pedestrian injury risk observed from German in-depth accident data.

PubMed

Li, Guibing; Lyons, Mathew; Wang, Bingyu; Yang, Jikuang; Otte, Dietmar; Simms, Ciaran

2017-04-01

Quantified relationships between passenger car front shape and pedestrian injury risk derived from accident data are sparse, especially considering the significant recent changes in car front design. The purpose of this paper is therefore to investigate the detailed effects of passenger car front shape on injury risk to a pedestrian's head, thorax, pelvis and leg in the event of a vehicle pedestrian impact. Firstly, an accident sample of 594 pedestrian cases captured during 2000-2015 from the German In-Depth Accident Study (GIDAS) database was employed. Multicollinearity diagnostic statistics were then used to detect multicollinearity between the predictors. Following this, logistic regression was applied to quantify the effects of passenger car front shape on injury risks while controlling for impact speed and pedestrian age. Results indicate that the bumper lower depth (BLD), bumper lower height (BLH), bumper upper height (BUH) and normalised bumper lower/upper height (NBLH/NBUH) are statistically significant for AIS2+ leg injury risk. The normalised bonnet leading edge height (NBLEH) has a statistically significant influence on AIS2+ femur/pelvis injury occurrence. The passenger car front shape did not show statistical significance for AIS3+ thorax and head injuries. The impact speed and pedestrian age are generally significant factors influencing AIS2+ leg and pelvis injuries, and AIS3+ thorax and head injuries. However, when head impacts are fixed on the central windscreen region both pedestrian age and impact speed are not statistically significant for AIS3+ head injury. For quantified effects, when controlling for speed, age and BUH, an average 7% and 6% increase in AIS2+ leg injury odds was observed for every 1cm increase in BLD and BLH respectively; 1cm increase in BUH results in a 7% decrease in AIS2+ leg injury odds when the BLD or BLH are fixed respectively (again controlling for impact speed and pedestrian age); the average AIS2+ femur/pelvis injury odds increase by 74% for a 10% increase in NBLEH. These findings suggest that passenger car bumpers should support the lower leg with a low and flat lower bumper and even contact up to the femur area with a high upper bumper which extends above the knee to protect the pedestrian's leg. A low passenger car bonnet leading edge helps to reduce femur/pelvis injury risk. The passenger car front shape parameters are less influential than impact speed and pedestrian age for pedestrian injury risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bear-inflicted injuries - a report from Nepal.

PubMed

Atreya, Alok; Kanchan, Tanuj; Nepal, Samata; Acharya, Jenash

2016-06-01

Upper Mustang in the Northern Himalayan range of Nepal is the home of brown bears (Ursusarctos). Low-plant biomass as a result of scanty rainfall in Upper Mustang is a reason for habitat overlap of humans and wild animals. Humans who enter into the wild to collect firewood and graze cattle are liable to wild animal attacks. Such attacks, especially by brown bears, are readily identified by the type of injuries. These are more commonly confined to head and neck regions. Cutting, gnawing and tearing by sharp teeth and claws produces specific pattern of injuries, which are devastating but seldom fatal. This article reports a rare case of brown bear injury inflicted upon a man from the Upper Mustang region in Nepal. © The Author(s) 2016.

Investigation to improve the resolution and range of a light imaging system for very thick tissues

NASA Astrophysics Data System (ADS)

Wist, Abund O.; Moon, Peter; Herr, Steven L.; Fatouros, Panos P.

1995-05-01

A high resolution light imaging system has been developed utilizing an HeNe (628 nm, 32 mW) and a receiver with post collimation mounted on an x, y table to scan the object. The image can be either recorded on a film or stored in a computer for display on a terminal. Tests show that the system in the regular mode is capable of detecting the spine and soft tissues in anesthetized mice, and of transilluminating fully an adult skull bone with a resolution for details better than one third mm. In teeth, all regular carious lesions, including incipient lesions larger than one third of a mm, can be seen in front or in the back of the tooth, none of which could be detected by dental x-ray systems. Applying a new high resolution mode, the resolution can be increased in teeth to less than 0.1 mm. Some difficulty still exists in detecting small lesions on occlusal or approximal surfaces.

Detailed study of upper mantle anisotropy in the upper mantle of eastern North America

NASA Astrophysics Data System (ADS)

Chen, X.; Levin, V. L.; Li, Y.

2016-12-01

We collected observations of core-refracted shear waves on a 1300 km long array crossing the eastern part of the North American continent from James Bay to the Fundy Basin. We combine data from the Earthscope Transportable Array, Canadian and US permanent observatories, and the recently completed Earthscope FlexArray QMIII.Past studies found ample evidence for directional dependence (anisotropy) of seismic wave speed in the upper mantle of this region. However, to date the lateral spacing of seismic observatories made direct comparisons between anisotropic structure and tectonic divisions evident on the surface challenging. With instruments spacing 50 km, and less near major tectonic boundaries such as the Grenville Front and the Appalachian Front, we can discriminate between gradual changes in anisotropic properties due to asthenospheric flow variations, and abrupt and localized changes likely to arise from juxtaposition of distinct lithospheric blocks.To insure lateral consistency of measurements we selected core-refracted shear waves that were observed over the entire length of our array. Also, since directional dependence of splitting parameters is a well recognized signature of vertical changes in anisotropic properties we examine observations from different directions, and look for systematic changes.Most locations show evidence for some degree of splitting in observed shear waves. Delays between fast and slow components estimated using rotation-correlation method range from 0.3 to 1.5 s. At most sites delay values vary considerably between individual phases measured. Fast polarizations are predominantly NE-SW, which agrees with numerous past studies of the region. Systematic directional dependence of fast polarization is seen at all sites we studied. Furthermore, the values of fast polarization appear to be similar along the entire array for individual events but vary from event to event. Both of these observations are consistent with the previously proposed notion of layered anisotropy in the upper mantle of the North American continent. We find localized changes in splitting parameters at the Grenville Front. The Appalachian Front, or the internal divisions of the Appalachian Orogen do not have obvious changes in splitting parameters associated with them.

Cerium Anomalies in Fossil Fish Teeth Reveal Changes in Bottom Water Oxygenation

NASA Astrophysics Data System (ADS)

Chun, C. O.; Scher, H. D.; Delaney, M. L.

2007-12-01

Shale-normalized rare earths and yttrium (REY) concentrations of fossil fish teeth in deep sea sediments display prominent negative cerium (Ce) anomalies and positive yttrium (Y) anomalies. These features are ultimately inherited from seawater and strongly indicate that fossil fish teeth preserve a seawater REY signature. In seawater, Ce+3 is oxidized to Ce+4, and Ce becomes depleted relative to the other REY's as it partitions into other phases (e.g., ferromanganese oxyhydroxides). The magnitude of Ce depletion in a water mass is thus related to its oxygen content. We hypothesize that changes in the oxygenation of bottom waters may be revealed by examining downcore variability in the magnitude of the Ce anomaly of fossil fish teeth. To test this hypothesis, REY concentrations were measured on samples of cleaned fossil fish teeth recovered from the late Paleogene to early Eocene sections of Ocean Drilling Program (ODP) Sites 1262 and 1263 (lower and upper Walvis Ridge, ODP Leg 208, South Atlantic Ocean). These sites are vertically offset (early Eocene paleodepths were 3700 and 1700 meters, respectively) and have been extensively studied to characterize the oceanic response to the Paleocene/Eocene Thermal Maximum (PETM). Manganese enrichment factors (Mn EF) determined from total digestions of samples from these sites reveal abrupt changes in the oxygenation of bottom waters across the PETM interval. Mn EF's decrease to crustal values (~1) during the PETM, which reflects the reduction of Mn oxides as bottom water oxygen levels were depleted. Mn EF's begin to increase to 6-8 during the 'recovery phase' following the PETM. The Ce anomaly for these samples, Ce/Ce*, was calculated according to the geometric approach reported by Lawrence et al. (2006, Aquatic Geochemistry 12, 39-72), where Ce* represents an interpolation of the expected shale-normalized Ce concentration from near neighbors. In this notation, when Ce/Ce* = 1 no Ce anomaly is present. At upper Walvis Ridge downcore Ce anomalies show a distinct excursion from pre-PETM values between 0.7-0.8 to values ~1.0 during the PETM event. The values return to pre-excursion levels during the recovery phase following the PETM. The results of this study closely follow the evolution of Mn EF's at Walvis Ridge sites. The smallest Ce anomalies (i.e., Ce/Ce* = 1) coincide with Mn EF's of 1, which provide independent evidence for low oxygen levels in the bottom waters bathing these locations. These results confirm the hypothesis that Ce anomalies in fossil fish teeth can be used to assess changes in the oxygenation of bottom waters.

An aegialodontid upper molar and the evolution of mammal dentition.

PubMed

Lopatin, Alexey V; Averianov, Alexander O

2006-08-25

The most obvious key synapomorphy of the therian mammals is the tribosphenic pattern of their molars. Tribosphenic teeth are capable of both shearing and grinding, which substantially increase effectiveness of food processing and, in turn, permit evolution of a wide range of dietary specializations. Functional tribospheny developed repeatedly during mammalian evolution but was successful only in the Boreosphenida. The earliest stage in the development of boreosphenidan tribospheny has remained poorly understood, being documented only by lower molars of aegialodontids. Here, we report a known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia.

10. Historic American Buildings Survey W. N. Manning, Photographer, January ...

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

10. Historic American Buildings Survey W. N. Manning, Photographer, January 26, 1935 HALL AND STAIRWAY FROM FRONT DOOR - Freeman-Caver-Christian House, Upper Friendship Road, Oxford, Calhoun County, AL

Canine tooth wear in captive little brown bats

USGS Publications Warehouse

Clark, Donald R.

1980-01-01

Upper canine teeth of little brown bats Myotis lucifugus lucifugus held in stainless steel wire mesh cages underwent severe wear which exceeded that observed previously in caged big brown bats, Eptesicus fuscus fuscus. This suggests a relationship between amount of wear and size of the caged bats with damage increasing as size decreases. Rapid wear of canine teeth by little brown bats resembled that observed in big brown bats in that it was limited to the first 2 weeks of captivity. This result indicates a universal interval for acclimation to cage conditions among vespertilionid bats. Dietary toxicants DDE and PCB did not affect the extent of wear. If bats are to be released to the wild, confinement in wire mesh cages should be avoided.

High-contrast x-ray microtomography in dental research

NASA Astrophysics Data System (ADS)

Davis, Graham; Mills, David

2017-09-01

X-ray microtomography (XMT) is a well-established technique in dental research. The technique has been used extensively to explore the complex morphology of the root canal system, and to qualitatively and quantitatively evaluate root canal instrumentation and filling efficacy in extracted teeth; enabling different techniques to be compared. Densitometric information can be used to identify and map demineralized tissue resulting from tooth decay (caries) and, in extracted teeth, the method can be used to evaluate different methods of excavation. More recently, high contrast XMT is being used to investigate the relationship between external insults to teeth and the pulpal reaction. When such insults occur, fluid may flow through dentinal tubules as a result of cracking or porosity in enamel. Over time, there is an increase in mineralization along the paths of the tubules from the pulp to the damaged region in enamel and this can be visualized using high contrast XMT. The scanner used for this employs time-delay integration to minimize the effects of detector inhomogeneity in order to greatly increase the upper limit on signal-to-noise ratio that can be achieved with long exposure times. When enamel cracks are present in extracted teeth, the presence of these pathways indicates that the cracking occurred prior to extraction. At high contrast, growth lines are occasionally seen in deciduous teeth which may have resulted from periods of maternal illness. Various other anomalies in mineralization resulting from trauma or genetic abnormalities can also be investigated using this technique.

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.

Slow Orthodontic Teeth Extrusion to Enhance Hard and Soft Periodontal Tissue Quality before Implant Positioning in Aesthetic Area

PubMed Central

Maiorana, C; Speroni, S; Herford, A S; Cicciù, M

2012-01-01

Approaching bone defects of jaws treatments, hard and soft tissue augmentation could be considered as a goal for clinicians when performing dental implant placement. The increase in patients who want cosmetic treatment puts practitioners in an awkward position when choosing the best therapy to obtain the most desirable results. A private dentist referred a young patient to the Department of Implantology in Milan in order to place implants in the upper jaw. Radiographic evaluation of the two upper anterior incisors confirmed that the teeth had a poor prognosis The anterior ridge volume was clinically analyzed and several therapeutic choices were evaluated. Rapid extractions and immediate implant positioning were not considered due to the vertical and horizontal components of the bone defect. Therefore, the surgical team decided on increasing the bone volume by using slow orthodontic teeth extrusion technique. After 3 months of orthodontic treatment, the angular intra-bony defects of 1.1 tooth was completely healed. Implant guided positioning, associated with a small bone graft, showed optimal results at the time of healing screw placement. The soft tissue conditioning was obtained by a provisional acrylic crown. The final application of two integral ceramic crowns showed excellent aesthetic results. Radiographic investigation at a 24 month follow-up confirmed the integration of the dental implants and the recovery of the bone defects. Several safe surgical techniques are available today for reconstructing atrophic jaws. However, the same technique applied on the posterior area did not give the same predictable results as in the anterior areas of the jaw. PMID:23056158

Radiographic Study of the Prevalence and Distribution of Hypodontia Associated with Unilateral and Bilateral Clef Lip and Palate in a Hungarian Population

PubMed Central

Berniczei-Roykó, Ádám; Tappe, Jan-Hendrik; Krinner, Axel; Gredes, Tomasz; Végh, András; Gábor, Katona; Linkowska-Świdzińska, Kamila; Botzenhart, Ute Ulrike

2016-01-01

Background Cleft defects are one of the most frequent birth-deformities of the orofacial region and they are commonly associated with anomalies of the tooth structure, size, shape, formation, eruption, and tooth number. The aim of our study was to evaluate the prevalence, distribution, and potential association of combined hypodontia in cleft-affected patients with regard to all types of teeth in both jaws in the permanent dentition. Material/Methods This retrospective radiographic analysis included patients with various types of clefts treated orthodontically in the Department of Orofacial Orthopedics and Orthodontics at Heim Pàl Children’s Hospital, Budapest. There were 150 patients (84 males, 66 females) with non-syndromic unilateral (UCLP; n=120 patients) or bilateral (BCLP; n=30 patients) cleft formation (lip, alveolus and palate) who met the inclusion criteria. Statistical analysis was performed using the chi-square test and Fisher’s exact test (significance level p<0.05). Results Hypodontia was significantly more frequent in patients with cleft-sided lateral incisor (104 patients, 69%), with a total of 235 missing teeth, followed by the second premolars of the upper and lower jaw. A significant correlation of congenital missing teeth was observed in left-sided clefts between the upper and lower second premolar in the cleft area. Conclusions Hypodontia inside and outside the cleft area was frequently observed. This should affect the therapy plans, especially if the cleft-sided premolar is also absent. Further comprehensive research including numerous random samples is necessary for better estimating other possible associations. PMID:27767023

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

PubMed

Zilberman, Uri; Bibi, Haim

2016-01-01

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

Torque resistance of different stainless steel wires commonly used for fixed retainers in orthodontics.

PubMed

Arnold, Dario T; Dalstra, Michel; Verna, Carlalberta

2016-06-01

Movements of teeth splinted by fixed retention wires after orthodontic treatment have been observed. The aetiological factors for these movements are unknown. The aim of this in vitro study was to compare the resistance to torque of different stainless steel wires commonly used for fixed retainers in orthodontics. Torquing moments acting on a retainer wire were measured in a mechanical force testing system by applying buccal crown torque to an upper lateral incisor in both a 3-teeth and in a 2-teeth setup. Seven stainless steel wires with different shape, type (plain, braided, coaxial, or chain) and dimensions were selected for this study. For a torquing angle of 16.2° in the 3-teeth setup torsion moments can vary between 390 cNmm and 3299 cNmm depending on the retainer wire. For the 2-teeth setup the torsion moments are much smaller. Exposure to the flame of a butane-gas torch for 10 seconds to anneal the wire reduces the stiffness of the retainer wire. Clinicians must select wires for fixed retainers very carefully since the difference in resistance to torque is large. A high level of torque control can be achieved with a plain 0.016 × 0.016-inch or a braided 0.016 × 0.022-inch stainless steel wire. A tooth attached by a retainer wire to only one neighbouring tooth is less resistant to torque than a tooth connected to two neighbouring teeth. Annealing a retainer wire with a flame reduces the stiffness of the wire markedly and can lead to a non-uniform and non-reproducible effect.

[Alveolar bone thickness and root length changes in the treatment of skeletal Class III patients facilitated by improved corticotomy: a cone-beam CT analysis].

PubMed

Wu, Jiaqi; Jiang, Jiuhui; Xu, Li; Liang, Cheng; Li, Cuiying; Xu, Xiao

2015-04-01

To evaluate the alveolar bone thickness and root length changes of anterior teeth with cone-beam computed tomography (CBCT). CBCT scans were taken for 12 skeletal Class III patients who accepted the improved corticotomy (IC) procedures during pre-surgical orthodontics. The CBCT data in T1 (the maxillary dental arch was aligned and leveled) and T2 (extraction space closure) were superimposed and the alveolar bone thickness at root apex level and root length measurements were done. From T1 to T2, the buccal alveolar bone thickness for the upper lateral incisors increased from (1.89±0.83) to (2.47±1.02) mm (P<0.05), and for central incisors and for canines from (2.32±0.71) to (2.68±1.48) mm and from (2.28±1.08) to (2.41±1.40) mm, respectively. According to Sharpe Grading System, the root resorption grade for 69 teeth of 72 was located in Grade 1, two teeth in Grade 2, one tooth in Grade 3. The improved corticotomy had the potential to increase the buccal alveolar bone thickness and the root resorption in most teeth was in Grade 1 according to Sharpe grading system.

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

NASA Astrophysics Data System (ADS)

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

2014-06-01

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

Maxillary canine impactions related to impacted central incisors: two case reports.

PubMed

Bayram, Mehmet; Ozer, Mete; Sener, Ismail

2007-09-01

The purpose of this case report is to describe the combined surgical and orthodontic treatment of two cases with an impacted maxillary central incisor and canine in the same quadrant and to discuss the causal relationship between them. The most common causes of canine impactions are usually the result of one or more factors such as a long path of eruption, tooth size-arch length discrepancies, abnormal position of the tooth bud, prolonged retention or early loss of the deciduous canine, trauma, the presence of an alveolar cleft, ankylosis, cystic or neoplastic formation, dilaceration of the root, supernumerary teeth, and odontomas. Although impaction of the maxillary central incisor is almost as prevalent as impacted canines its etiology is different. The principal factors involved in causing the anomaly are supernumerary teeth, odontomas, and trauma. Case #1: A 10.5-year-old girl in the early mixed dentition stage presented with a chief complaint of the appearance of her anterior teeth. She had a Class I skeletal pattern and a history of trauma to the maxillary central incisors at age five with premature exfoliation. Radiographs revealed an impacted upper right central incisor in the region of the nasal floor, delayed eruption of the maxillary permanent central incisor, and the adjacent lateral incisor was inclined toward the edentulous space. Treatment was done in two stages consisting of surgical exposure and traction of the impacted central incisor and fixed orthodontic treatment. Case #2: An 11.5-year-old girl presented for orthodontic treatment with the chief complaint of an unerupted tooth and the appearance of her upper anterior teeth. She was in the late mixed dentition period with a Class III skeletal pattern along with an anterior cross-bite with some maxillary transverse deficiency. The maxillary right canine and central incisor were absent, but the maxillary right deciduous canine was still present. Treatment included arch expansion followed by surgical exposure and traction of the impacted teeth and fixed orthodontic treatment. This case report provides some evidence of a significant environmental influence of an impacted maxillary central incisor on the path of eruption of the ipsilateral maxillary canine. When an impacted maxillary central incisor exists, the maxillary lateral incisor's root might be positioned distally into the path of eruption of the maxillary canine preventing its normal eruption. Ongoing assessment and early intervention might help to prevent such adverse situations from occurring.

[Effect of dental arch length decrease during orthodontic treatment in the upper airway development. A review].

PubMed

Haddad, Stéphanie; Kerbrat, Jean-Baptiste; Schouman, Thomas; Goudot, Patrick

2017-03-01

A possible relation between an upper airway space decrease and the development of obstructive sleep apnea syndrom explains the importance to know the effect of the modification of dental arch length on the upper airway during orthodontic treatment. The aim of this article is to expose recent knowledge about upper airway development and dental arch length decrease factors, to determine the influence of this decrease on upper airway development. A review was done to determine the upper airway normal development, to define dental arch to specify if an ideal position of dental arch on apical base exists. All of the length dental arch decrease factors during orthodontic treatment (dental extraction, dental agenesis and dental malpositions) and their upper airway resounding were searched. Some authors found a diminution of upper airway space after premolars extractions while others didn't found this diminution after extractions premolars when incisor retraction is finished. A decrease of transversal maxillary diameter and nasal cavity may be due to absence of permanent teeth. The effect of dental arch length decrease during orthodontic treatment in the upper airway development was not scientifically proved. However we had to be vigilant and adapt our orthodontic treatment case by case to avoid an upper airway modification. © EDP Sciences, SFODF, 2017.

15. Historic American Buildings Survey W. N. Manning, Photographer, January ...

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

15. Historic American Buildings Survey W. N. Manning, Photographer, January 26, 1935 FRONT AND SIDE VIEW OF OLD STORE, S.E. - Freeman-Caver-Christian House, Upper Friendship Road, Oxford, Calhoun County, AL

1. Historic American Buildings Survey E. W. Russell, Photographer, September ...

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

1. Historic American Buildings Survey E. W. Russell, Photographer, September 2, 1936 UPPER PORTION OF SOUTH FRONT. W. H. ROSS HOME - 602 GOVERNMENT STREET - Ross House, 602 Government Street, Mobile, Mobile County, AL

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, Terry R.

1983-01-01

A method and a cutter for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head (72) has a hollow body (76) with a generally circular base and sloping upper surface. A hollow shaft (74) extends from the hollow body (76). Cutter teeth (78) are mounted on the upper surface of the body (76) and relatively small holes (77) are formed in the body (76) between the cutter teeth (78). Relatively large peripheral flutes (80) around the body (76) allow material to drop below the drill head (72). A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale.

Environmental stress increases variability in the expression of dental cusps.

PubMed

Riga, Alessandro; Belcastro, Maria Giovanna; Moggi-Cecchi, Jacopo

2014-03-01

Teeth are an important model for developmental studies but, despite an extensive literature on the genetics of dental development, little is known about the environmental influences on dental morphology. Here we test whether and to what extent the environment plays a role in producing morphological variation in human teeth. We selected a sample of modern human skulls and used dental enamel hypoplasia as an environmental stress marker to identify two groups with different stress levels, referred to as SG ("stressed" group) and NSG ("nonstressed" group). We collected data on the occurrence and the relative development of 15 morphological traits on upper molars using a standard methodology (ASU-DAS system) and then we compared the frequencies of the traits in the two groups. Overall, the results suggest that (a) stressors like malnutrition and/or systemic diseases have a significant effect on upper molar morphology; (b) stress generates a developmental response which increases the morphological variability of the SG; and (c) the increase in variability is directional, since individuals belonging to the SG have more developed and extra cusps. These results are consistent with the expectations of the current model of dental development. Copyright © 2013 Wiley Periodicals, Inc.

Interdisciplinary treatment of an adult with a unilateral cleft lip and palate

PubMed Central

Al-Ruwaithi, Moatazbellah M; Al-Fraidi, Ahmad A; Al-Tamimi, Tawfiq S; Al-Shehri, Ali S

2014-01-01

The management of cleft lip and palate (CLP) requires an interdisciplinary team providing comprehensive care. The present report presents an interdisciplinary approach for the care of a cleft patient. A 17-year-old male patient presented with a a chief complaint of “unpleasant appearance of my teeth” and a history of surgical repair of unilateral CLP on the left side. He presented with Class III molar relationships, Class II canine relationships, crossbite related to maxillary right first premolar and lateral incisor, severe maxillary and mandibular crowding, maxillary anterior tooth size deficiency, congenitally missing upper left lateral incisor. Patient was treated with a pre-adjusted edgewise appliance in conjunction with extraction of multiple teeth and distalization of the lower right first molar using a temporary anchorage device. In addition, alveolar bone graft and implant were placed to restore the missing upper left lateral incisor and a final esthetic work was performed for anterior teeth. The case was finished with Class I molar and canine relationships, minimal overjet and overbite. Total treatment time was about 31 months with satisfactory results. Post-treatment evaluation after 8 months showed stable results. PMID:24987659

Geologic Map of the Sulphur Mountain Quadrangle, Park County, Colorado

USGS Publications Warehouse

Bohannon, Robert G.; Ruleman, Chester A.

2009-01-01

The main structural element in the Sulphur Mountain quadrangle is the Elkhorn thrust. This northwest-trending fault is the southernmost structure that bounds the west side of the Late Cretaceous and early Tertiary Front Range basement-rock uplift. The Elkhorn thrust and the Williams Range thrust that occurs in the Dillon area north of the quadrangle bound the west flank of the Williams Range and the Front Range uplift in the South Park area. Kellogg (2004) described widespread, intense fracturing, landsliding, and deep-rooted scarps in the crystalline rocks that comprise the upper plate of the Williams Range thrust. The latter thrust is also demonstrably a low-angle structure upon which the fractured bedrock of the upper plate was translated west above Cretaceous shales. Westward thrusting along the border of the Front Range uplift is probably best developed in that area. By contrast, the Elkhorn in the Sulphur Mountain quadrangle is poorly exposed and occurs in an area of relatively low relief. The thrust also apparently ends in the central part of the quadrangle, dying out into a broad area of open, upright folds with northwest axes in the Sulphur Mountain area.

Factors associated with negative self-perception of oral health among institutionalized elderly.

PubMed

Melo, Laércio Almeida de; Sousa, Meily de Mello; Medeiros, Annie Karoline Bezerra de; Carreiro, Adriana da Fonte Porto; Lima, Kenio Costa de

2016-11-01

The aim of this study was to determine self-perception of oral-health in institutionalized elderly, and look into the sociodemographic and clinical aspects associated with negative self-perception. One hundred and sixty-six elderly were assessed by answering a self-perception question that predicts the GOHAI (Geriatric Oral Health Assessment Index). Sociodemographic data was obtained from a previously validated questionnaire and clinical data taken from the WHO file and QST-TMD used to check the existence of TMD (temporomandibular disturbance). The data gathered was submitted to Mann-Whitney, Fisher's Exact and Chi-squared tests with a 5% significance level. The average age of the study population was 80.5, and 75.9% were women. The mean DMFT (decayed, missing, and filled teeth in permanent teeth) was 28.9, the majority of the sample subject (65%) reported good to excellent teeth, gums and prostheses (dentures and bridges). Three questions in the TMD questionnaire (QST-DTM) were associated with negative self-perception. Those claiming that their jaws "lock" when they open or close their mouth, who always have pain at the front or side of their jaw, or whose jaws get tired during the course of the day are less satisfied with their oral health. We conclude that clinical and sociodemographic conditions have little influence on self-perception of oral health, possibly because pain is the main factor associated with negative self-perception in these individuals.

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

Huang Meijuan; Jiang Yu; State Key Laboratory of Biotherapy, West China Hospital, Medical School, Sichuan University, Chengdu

Purpose: To investigate the role of early or up-front radiotherapy (RT), the optimal RT dose required to achieve appropriate treatment outcome and prognostic factors for patients with localized extranodal NK/T-cell lymphoma, nasal-type, in the upper aerodigestive tract. Methods and Materials: Eighty-two patients were reviewed. Eight patients were treated with chemotherapy (CT) alone, 9 patients received RT alone, and 65 patients were given combined modality treatment of CT and RT (CMT). Of those 74 patients receiving RT, 31 patients were given up-front RT, whereas CT was the initial therapy for 43 patients and 41 of those 43 patients received early RT.more » Results: Five-year overall survival (OS) and disease-free survival (DFS) were 52.3% and 39.2%, respectively. RT was the only independent prognostic factor for both OS and DFS at both the univariate and multivariate level. The 5-year OS and DFS were better in patients receiving {>=}54 Gy of RT as compared with that of <54 Gy (5-year OS 75.5% vs. 46.1%, p = 0.019; 5-year DFS 60.3% vs. 33.4%, p = 0.004). Up-front RT presented better survival in Stage I patients when compared with that of initial CT followed by early RT (5-year OS 90.0% vs. 48.9%, p = 0.012; 5-year DFS 78.7% vs. 39.9%, p = 0.021). Conclusion: Early or up-front RT had an essential role in improved OS and DFS in patients with localized extranodal NK/T-cell lymphoma, nasal-type, in the upper aerodigestive tract. The recommended tumor dose was at least 54 Gy. Up-front RT may yield more benefits on survival in patients with Stage I disease.« less

Multistate models of bigheaded carps in the Illinois River reveal spatial dynamics of invasive species

USGS Publications Warehouse

Coulter, Alison A; Brey, Marybeth; Lubejko, Matthew; Kallis, Jahn L; Glover, David C.; Whitledge, Gregory W; Garvey, James E.

2018-01-01

Knowledge of the spatial distributions and dispersal characteristics of invasive species is necessary for managing the spread of highly mobile species, such as invasive bigheaded carps (Bighead Carp [Hypophthalmichthys nobilis] and Silver Carp [H. molitrix]). Management of invasive bigheaded carps in the Illinois River has focused on using man-made barriers and harvest to limit dispersal towards the Laurentian Great Lakes. Acoustic telemetry data were used to parameterize multistate models to examine the spatial dynamics of bigheaded carps in the Illinois River to 1) evaluate the effects of current dams on movement, 2) identify how individuals distribute among pools, and 3) gauge the effects of reductions in movement towards the invasion front. Multistate models estimated that movement was generally less likely among upper river pools (Starved Rock, Marseilles, and Dresden Island) than the lower river (La Grange and Peoria) which matched the pattern of gated vs. wicket style dams. Simulations using estimated movement probabilities indicated that Bighead Carp accumulate in La Grange Pool while Silver Carp accumulate in Alton Pool. Fewer Bighead Carp reached the upper river compared to Silver Carp during simulations. Reducing upstream movement probabilities (e.g., reduced propagule pressure) by ≥ 75% into any of the upper river pools could reduce upper river abundance with similar results regardless of location. Given bigheaded carp reproduction in the upper Illinois River is limited, reduced movement towards the invasion front coupled with removal of individuals reaching these areas could limit potential future dispersal towards the Great Lakes.

Tidal variations of flow convergence, shear, and stratification at the Rio de la Plata estuary turbidity front

NASA Astrophysics Data System (ADS)

FramiñAn, Mariana B.; Valle-Levinson, Arnoldo; Sepúlveda, HéCtor H.; Brown, Otis B.

2008-08-01

Intratidal variability of density and velocity fields is investigated at the turbidity front of the Río de la Plata Estuary, South America. Current velocity and temperature-salinity profiles collected in August 1999 along a repeated transect crossing the front are analyzed. Horizontal and vertical gradients, stability of the front, convergence zones, and transverse flow associated to the frontal boundary are described. Strong horizontal convergence of the across-front velocity and build up of along-front velocity shear were observed at the front. In the proximity of the front, enhanced transverse (or along-front) flow created jet-like structures at the surface and near the bottom flowing in opposite directions. These structures persisted throughout the tidal cycle and were advected upstream (downstream) by the flood (ebb) current through a distance of ˜10 km. During peak flood, the upper layer flow reversed from its predominant downstream direction and upstreamflow occupied the entire water column; outside the peak flood, two-layer estuarine circulation dominated. Changes in density field were observed in response to tidal straining, tidal advection, and wind-induced mixing, but stratification remained throughout the tidal cycle. This work demonstrates the large spatial variability of the velocity field at the turbidity front; it provides evidence of enhanced transverse circulation along the frontal boundary; and reveals the importance of advective and frictional intratidal processes in the dynamics of the central part of the estuary.

Modern mammal origins: evolutionary grades in the Early Cretaceous of North America.

PubMed

Jacobs, L L; Winkler, D A; Murry, P A

1989-07-01

Major groups of modern mammals have their origins in the Mesozoic Era, yet the mammalian fossil record is generally poor for that time interval. Fundamental morphological changes that led to modern mammals are often represented by small samples of isolated teeth. Fortunately, functional wear facets on teeth allow prediction of the morphology of occluding teeth that may be unrepresented by fossils. A major step in mammalian evolution occurred in the Early Cretaceous with the evolution of tribosphenic molars, which characterize marsupials and placentals, the two most abundant and diverse extant groups of mammals. A tooth from the Early Cretaceous (110 million years before present) of Texas tests previous predictions (based on lower molars) of the morphology of upper molars in early tribosphenic dentitions. The lingual cusp (protocone) is primitively without shear facets, as expected, but the cheek side of the tooth is derived (advanced) in having distinctive cusps along the margin. The tooth, although distressingly inadequate to define many features of the organism, demonstrates unexpected morphological diversity at a strategic stage of mammalian evolution and falsifies previous claims of the earliest occurrence of true marsupials.

[The smile line, a literature search].

PubMed

van der Geld, P A; van Waas, M A

2003-09-01

Beautiful teeth, visible when smiling, are in line with the present ideal of beauty. The display of teeth when smiling is determined by the smile line: the projection of the lower border of the upper lip on the maxillary teeth when smiling. On the basis of a literature search the determining methods of the smile line are discussed, demographic data of the position of the smile line are given, and factors of influence are examined. There is no unequivocal method for determining the position of the smile line. A rough distinction can be made between qualitative and (semi)-quantitative methods. The (semi)-quantitative methods have clear advantages for research purposes, but their reliability is unknown. It was demonstrated that among minimally 40% of subjects the maxillary gingiva was not visible when smiling. The mandibular gingiva was not visible when smiling among more than 90% of subjects. Furthermore, it appeared that among women the smile line was on average higher situated than among men and that it has not yet been proven that the smile line will be situated lower when growing older.

A description on pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis (Valenciennes 1847) in Malaysian waters

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

Abidin, Diana Atiqah Zainal, E-mail: diana.atiqah@gmail.com; Hashim, Marina; Ghaffar, Mazlan Abd., E-mail: magfish05@yahoo.com

2015-09-25

Information on the feeding mechanism and diet of halfbeak fish species in harsh estuarine environment ecosystem is still lacking. The present study investigates the fine structure of pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis. A total of 84 halfbeak fish samples have been collected from the coastal water of Peninsular Malaysia using fishing rod. Scanning electron microscopy was used to examine the micrographs of fine microstructure of the pharyngeal teeth. The fundamental anatomy of pharyngeal jaw apparatus displayed that the upper pharyngeal jaw (third pharyngobranchials) displays larger size of hook-like or tricuspid teeth which was analogous tomore » tricuspid morphology. The lower pharyngeal jaw (fifth ceratobranchial) bears mainly conical teeth and appears triangular shape with two, short projections. The estimated TROPH values (1 − 3.2±0.55) denoted that halfbeak fish were omnivores in nature. The findings of this study was found to be useful as a baseline information for a better representation of the trophic flows associated with large medium and small surface water fishes.« less

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

NASA Astrophysics Data System (ADS)

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

2015-08-01

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

A Combined Periodontal – Prosthetic Treatment Approach to Manage Unusual Gingival Visibility in Resting Lip Position and Inversely Inclined Upper Anterior Teeth: A Case Report with Discussion

PubMed Central

Biniraj, K R; Janardhanan, Mahija; Sunil, M M; Sagir, Mohammed; Hariprasad, A; Paul, Tony P; Emmatty, Rishi

2015-01-01

Excessive gingival visibility during smile is a common esthetic complaint in dentistry, but excessive gingival visibility in resting lip position is relatively uncommon condition. Several exclusive radical to conservative surgical treatment or its combination with orthodontic therapy to treat this condition are within the reach of every patient nowadays. A case report of an excessive gingival visibility because of altered passive eruption along with inversely inclined maxillary anterior teeth is presented here. A relatively simple treatment approach combining periodontal and restorative therapy is used here to achieve the desirable aesthetic results. The gingival exposure resulting from altered passive eruption was completely managed by a gingivectomy, but the inclined appearance of teeth was still an aesthetic complaint. After complete healing of gingivectomy surgery, appropriately designed crowns were given to rectify the inversely inclined appearance. A complete rehabilitation of patient’s smile could be achieved, the case was followed up for 3 years and the condition was found satisfactory. PMID:25878482

Nonmetric traits of permanent posterior teeth in Kerala population: A forensic overview

PubMed Central

Baby, Tibin K; Sunil, S; Babu, Sharlene Sara

2017-01-01

Introduction: Dental morphology is a highly heritable characteristic which is stable with time and has a fairly high state of preservation. Nonmetric dental traits have crucial role in ethnic classifications of a population that helps in forensic racial identification purposes. Aims and Objectives: To determine the frequency and variability of possible nonmetric tooth traits using extracted permanent posterior teeth from Kerala population for discerning racial ethnicity. Materials and Methods: This qualitative, cross-sectional study was carried out using 1743 extracted intact permanent posterior teeth collected from different dental clinics situated all over Kerala. Results: The more common features on premolars were multiple lingual cusps (31.21%), distal accessary ridges (16.28%) and Tom's root (17.9%). In upper first molars, Carabelli trait expression was 17.78% and other common features included metaconulo, cusp 5 and enamel extensions. Conclusion: Posterior tooth traits had variable expression in the study population. Low prevalence rate of Carabelli trait in this study is characteristic of Asian population. This research explored new elements of invaluable tooth traits values to understand racial ethnicity of Kerala population. PMID:28932045

A description on pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis (Valenciennes 1847) in Malaysian waters

NASA Astrophysics Data System (ADS)

Abidin, Diana Atiqah Zainal; Hashim, Marina; Das, Simon K.; Ghaffar, Mazlan Abd.

2015-09-01

Information on the feeding mechanism and diet of halfbeak fish species in harsh estuarine environment ecosystem is still lacking. The present study investigates the fine structure of pharyngeal jaw apparatus and diets of halfbeak fish Zenarchopterus buffonis. A total of 84 halfbeak fish samples have been collected from the coastal water of Peninsular Malaysia using fishing rod. Scanning electron microscopy was used to examine the micrographs of fine microstructure of the pharyngeal teeth. The fundamental anatomy of pharyngeal jaw apparatus displayed that the upper pharyngeal jaw (third pharyngobranchials) displays larger size of hook-like or tricuspid teeth which was analogous to tricuspid morphology. The lower pharyngeal jaw (fifth ceratobranchial) bears mainly conical teeth and appears triangular shape with two, short projections. The estimated TROPH values (1 - 3.2±0.55) denoted that halfbeak fish were omnivores in nature. The findings of this study was found to be useful as a baseline information for a better representation of the trophic flows associated with large medium and small surface water fishes.

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water.

PubMed

Molina-Frechero, Nelly; Nevarez-Rascón, Martina; Nevarez-Rascón, Alfredo; González-González, Rogelio; Irigoyen-Camacho, María Esther; Sánchez-Pérez, Leonor; López-Verdin, Sandra; Bologna-Molina, Ronell

2017-01-12

Objective : To identify adolescents' self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods : A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs). Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF) index on the upper front teeth. Results : A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2-3 (50%), TF 4-5 (45.6%) and TF 6-7 (4.4%) for medium SES and TF 2-3 (12.3%), TF 4-5 (67.1%) and TF 67 (20.6%) for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs ( p < 0.05). The multiple regression model found differences between TF levels and self-perception, with a 6-7 TF level for concerns about color (OR = 1.6), smile (OR = 1.2) and appearance (OR = 3.36). Conclusions : Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases.

Microlepidogaster arachas, a new species of hypoptopomatine catfish (Siluriformes: Loricariidae) from the upper rio Paraná basin, Brazil.

PubMed

Martins, Fernanda O; Calegari, Bárbara B; Langeani, Francisco

2013-01-22

Microlepidogaster arachas Martins, Calegari & Langeani, sp. nov., a new Hypoptopomatinae, is described from the upper rio Paraná basin. The new species is distinguished from M. longicolla and M. dimorpha by having the anterior portion of the compound supraneural plus first dorsal-fin proximal radial contacting the neural spine of the ninth vertebra. The new species differs from M. perforatus by having 18-29 dentary teeth; median series of lateral plates complete, reaching caudal-peduncle end, and continuous lateral line; and 20-24 mid-dorsal plates. Microlepidogaster arachas is further distinguished from its congeners by several other osteological features.

Minimal wave speed for a class of non-cooperative reaction-diffusion systems of three equations

NASA Astrophysics Data System (ADS)

Zhang, Tianran

2017-05-01

In this paper, we study the traveling wave solutions and minimal wave speed for a class of non-cooperative reaction-diffusion systems consisting of three equations. Based on the eigenvalues, a pair of upper-lower solutions connecting only the invasion-free equilibrium are constructed and the Schauder's fixed-point theorem is applied to show the existence of traveling semi-fronts for an auxiliary system. Then the existence of traveling semi-fronts of original system is obtained by limit arguments. The traveling semi-fronts are proved to connect another equilibrium if natural birth and death rates are not considered and to be persistent if these rates are incorporated. Then non-existence of bounded traveling semi-fronts is obtained by two-sided Laplace transform. Then the above results are applied to some disease-transmission models and a predator-prey model.

A holographic system that records front-surface detail of a scene moving at high velocity

NASA Technical Reports Server (NTRS)

Kurtz, R. L.; Loh, H. Y.

1972-01-01

A holographic technique that uses an elliptical orientation for the holographic arrangement is discussed. It is shown that the degree of image degradation is not only a function of exposure time but also of the system used. The form of the functional system dependence is given, as well as the results of several systems tested, which verify this dependence. It is further demonstrated that the important parameter is the total motion of the target. Using the experimentally determined resolution of front-surface detail from a target with a velocity of 17,546 centimeters per second, an upper limit on target velocity for resolution of front-surface detail for a given system can be predicted.

Food and Growth. Seychelles Integrated Science. [Teacher and Pupil Booklets]. Unit 7.

ERIC Educational Resources Information Center

Brophy, M.; Fryars, M.

Seychelles Integrated Science (SIS), a 3-year laboratory-based science program for students (ages 11-15) in upper primary grades 7, 8, and 9, was developed from an extensive evaluation and modification of previous P7-P9 materials. This P8 SIS unit examines: (1) the role played by bones, muscles, and teeth and the importance of developing and…

The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru.

PubMed

Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; de Muizon, Christian; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle

2010-07-01

The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths. Lacking a functional upper dentition, it relies on suction for catching its prey; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as raptorial (versus suction) feeders, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12-13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding.

A new species of Hyphessobrycon (Characiformes, Characidae) from the upper Guaviare River, Orinoco River Basin, Colombia

PubMed Central

García-Alzate, Carlos A.; Urbano-Bonilla, Alexander; Taphorn, Donald C.

2017-01-01

Abstract Hyphessobrycon klausanni sp. n. is described from small drainages of the upper Guaviare River (Orinoco River Basin) in Colombia. It differs from all congeners by having a wide, conspicuous, dark lateral stripe extending from the anterior margin of the eye across the body and continued through the middle caudal-fin rays, and that covers (vertically) three or four horizontal scale rows. It also differs by having an orange-yellow stripe extending from the anterosuperior margin of the eye to the caudal peduncle above the lateral line in life. It differs from all other species of Hyphessobrycon that have a similar dark lateral stripe: H. cyanotaenia, H. loretoensis, H. melanostichos, H. nigricinctus, H. herbertaxelrodi, H. eschwartzae, H. montogoi, H. psittacus, H. metae, H. margitae, H. vanzolinii, and H. peruvianus in having only three or four pored scales in the lateral line, 21 to 24 lateral scales and six teeth in the inner premaxillary row. Hyphessobrycon klausanni differs from H. loretoensis in having seven to eight maxillary teeth (vs. three to four) and in having a longer caudal peduncle (12.4–17.0% SL vs. 4.6–8.0% SL). Additionally Hyphessobrycon klausanni can be distinguished from the other species of Hyphessobrycon with a dark lateral stripe from the Orinoco River Basin (H. metae and H. acaciae) in having two teeth in the outer premaxillary row (vs. three to four) and 10 branched pectoral–fin rays (vs. 11 to 12). It further differs from H. metae by the length of the snout (17.6–22.8% HL vs. 9.9–15.2% HL) and by the length of the caudal peduncle (12.4–17.0% SL vs. 7.3–11.8% SL). PMID:28769647

Craniofacial abnormalities in homozygous Small eye (Sey/Sey) embryos and newborn mice.

PubMed

Kaufman, M H; Chang, H H; Shaw, J P

1995-06-01

The Small eye (Sey) gene in the mouse is lethal in the homozygous state. It is located on chromosome 2, is a mutation in the Pax-6 gene, and is genetically homologous with the human aniridia 2 (AN2) gene mutation. Numerous studies over the last few years, using genetic and molecular biological approaches, have investigated both the location of the gene as well as its possible mode of action. In the homozygous state, the primary defect appears to be limited to the failure of differentiation of the presumptive lens and nasal placodes. Such mice therefore display a characteristic phenotype; they possess neither eyes nor any nasal derivatives. Their heterozygous (Sey/+) and normal (+/+) littermates may be distinguished before birth only by a detailed examination of their eyes. Few detailed morphological/histological studies have been undertaken to date in the Sey/Sey embryos and newborn, and in the present study we describe a variety of craniofacial abnormalities that have not previously been reported. We observed, with one exception, delayed closure of the palate, and the presence in 80% of mice of an abnormal complement of upper incisor teeth, so that 35% possessed 1 supernumerary tooth while 45% possessed 2 supernumerary teeth. In these mice, a total of either 3 or 4, rather than the normal complement of 2, upper incisor teeth were present. Possibly the most unexpected finding, however, was the presence of a median cartilaginous rod-like structure which protruded between the 2 maxillae to give the Alizarin red S and Alcian blue-stained 'cleared' skulls of the newborn mice a characteristic 'unicorn-like' appearance. While this structure appeared to be a rostral extension of the chondrocranium, its exact derivation is unclear.

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

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

Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

2009-09-27

To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoommore » activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.« less

Spacesuit Soft Upper Torso Sizing Systems

NASA Technical Reports Server (NTRS)

Graziosi, David; Splawn, Keith

2011-01-01

The passive sizing system consists of a series of low-profile pulleys attached to the front and back of the shoulder bearings on a spacesuit soft upper torso (SUT), textile cord or stainless steel cable, and a modified commercial ratchet mechanism. The cord/cable is routed through the pulleys and attached to the ratchet mechanism mounted on the front of the spacesuit within reach of the suited subject. Upon actuating the ratchet mechanism, the shoulder bearing breadth is changed, providing variable upper torso sizing. The active system consists of a series of pressurizable nastic cells embedded into the fabric layers of a spacesuit SUT. These cells are integrated to the front and back of the SUT and are connected to an air source with a variable regulator. When inflated, the nastic cells provide a change in the overall shoulder bearing breadth of the spacesuit and thus, torso sizing. The research focused on the development of a high-performance sizing and actuation system. This technology has application as a suit-sizing mechanism to allow easier suit entry and more accurate suit fit with fewer torso sizes than the existing EMU (Extravehicular Mobility Unit) suit system. This advanced SUT will support NASA s Advanced EMU Evolutionary Concept of a two-sizes-fit-all upper torso for replacement of the current EMU hard upper torso (HUT). Both the passive and nastic sizing system approaches provide astronauts with real-time upper torso sizing, which translates into a more comfortable suit, providing enhanced fit resulting in improved crewmember performance during extravehicular activity. These systems will also benefit NASA by reducing flight logistics as well as overall suit system cost. The nastic sizing system approach provides additional structural redundancy over existing SUT designs by embedding additional coated fabric and uncoated fabric layers. Two sizing systems were selected to build into a prototype SUT: one active and one passive. From manned testing, it was found that both systems offer good solutions to sizing a SUT to fit a crewmember. This new system provided improved suit don/doff over existing spacesuit designs as well as providing better fit at suit operational pressure resulting in improved comfort and mobility. It was found that a SUT with a sizing system may solve several problems that have plagued existing HUT designs, and that a SUT with a sizing system may be a viable option for advanced suit architectures.

Nesting habitat of the Tule Greater White-fronted Goose Anser albifrons elgasi

USGS Publications Warehouse

Densmore, R.V.; Ely, Craig R.; Bollinger, K.S.; Kratzer, S.; Udevitz, M.S.; Fehringer, D.J.; Rothe, T.C.

2006-01-01

This paper presents the first information on the availability and use of nesting habitat by the rare Tule Greater White-fronted Goose Anser albifrons elgasi. The breeding range was sampled by marking geese with radio transmitters on wintering and moulting areas, and tracking them to nest sites in Alaska. Nesting habitat was described at the scales of ecoregion, wetland ecosystem (National Wetlands Inventory (NWI) maps), vegetation type within wetland (Alaska Vegetation Classification (AVC) maps based on satellite imagery), and nest site. Tule Greater White-fronted Goose nests were located in boreal forest wetlands in the upper Cook Inlet Basin ecoregion. Nesting Tule Greater White-fronted Geese selected NWT Palustrine Seasonally Flooded wetlands and used NWI Palustrine Saturated wetlands in proportion to availability. Within these wetlands, Tule Greater White-fronted Geese used Needleleaf Forest, Low Shrub and Herbaceous (mostly graminoid) AVC classes for nest sites in proportion to availability Most (93%) Tule Greater White-fronted Geese nested > 75 m from open water ponds or lakes, and many nested in wetlands with little or no open water. Tule Greater White-fronted Geese nest only in a small breeding area near the most human-impacted area of the state, and continued development may limit the use of suitable nesting habitat.

Analysis of laser remote fusion cutting based on a mathematical model

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

Matti, R. S.; Department of Mechanical Engineering, College of Engineering, University of Mosul, Mosul; Ilar, T.

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, lasermore » remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.« less

Analysis of laser remote fusion cutting based on a mathematical model

NASA Astrophysics Data System (ADS)

Matti, R. S.; Ilar, T.; Kaplan, A. F. H.

2013-12-01

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.

Quantification of intrusive/retraction force and moment generated during en-masse retraction of maxillary anterior teeth using mini-implants: A conceptual approach.

PubMed

Felicita, A Sumathi

2017-01-01

The aim of the present study was to clarify the biomechanics of en-masse retraction of the upper anterior teeth and attempt to quantify the different forces and moments generated using mini-implants and to calculate the amount of applied force optimal for en-masse intrusion and retraction using mini-implants. The optimum force required for en-masse intrusion and retraction can be calculated by using simple mathematical formulae. Depending on the position of the mini-implant and the relationship of the attachment to the center of resistance of the anterior segment, different clinical outcomes are encountered. Using certain mathematical formulae, accurate measurements of the magnitude of force and moment generated on the teeth can be calculated for each clinical outcome. Optimum force for en-masse intrusion and retraction of maxillary anterior teeth is 212 grams per side. Force applied at an angle of 5o to 16o from the occlusal plane produce intrusive and retraction force components that are within the physiologic limit. Different clinical outcomes are encountered depending on the position of the mini-implant and the length of the attachment. It is possible to calculate the forces and moments generated for any given magnitude of applied force. The orthodontist can apply the basic biomechanical principles mentioned in this study to calculate the forces and moments for different hypothetical clinical scenarios.

Long-range transport of Asian pollution to the northeast Pacific: Seasonal variations and transport pathways of carbon monoxide

NASA Astrophysics Data System (ADS)

Liang, Qing; Jaeglé, Lyatt; Jaffe, Daniel A.; Weiss-Penzias, Peter; Heckman, Anna; Snow, Julie A.

2004-12-01

Continuous CO measurements were obtained at Cheeka Peak Observatory (CPO, 48.3°N, 124.6°W, 480 m), a coastal site in Washington state, between 9 March 2001 and 31 May 2002. We analyze these observations as well as CO observations at ground sites throughout the North Pacific using the GEOS-CHEM global tropospheric chemistry model to examine the seasonal variations of Asian long-range transport. The model reproduces the observed CO levels, their seasonal cycle and day-to-day variability, with a 5-20 ppbv negative bias in winter/spring and 5-10 ppbv positive bias during summer. Asian influence on CO levels in the North Pacific troposphere maximizes during spring and minimizes during summer, ranging from 91 ppbv (44% of total CO) to 52 ppbv (39%) along the Asian Pacific Rim and from 44 ppbv (30%) to 24 ppbv (23%) at CPO. Maximum export of Asian pollution to the western Pacific occurs at 20°-50°N during spring throughout the tropospheric column, shifting to 30°-60°N during summer, mostly in the upper troposphere. The model captures five particularly strong transpacific transport events reaching CPO (four in spring, one in winter) resulting in 20-40 ppbv increases in observed CO levels. Episodic long-range transport of pollutants from Asia to the NE Pacific occurs throughout the year every 10, 15, and 30 days in the upper, middle, and lower troposphere, respectively. Lifting ahead of cold fronts followed by transport in midlatitude westerlies accounts for 78% of long-range transport events reaching the NE Pacific middle and upper troposphere. During summer, convective injection into the upper troposphere competes with frontal mechanisms in this export. Most events reaching the NE Pacific lower troposphere below 2 km altitude result from boundary layer outflow behind cold fronts (for spring) or ahead of cold fronts (for other seasons) followed by low-level transpacific transport.

Easy fabrication of a new type of mouthguard incorporating a hard insert and space and offering improved shock absorption ability.

PubMed

Takeda, Tomotaka; Ishigami, Keiichi; Mishima, Osamu; Karasawa, Kensuke; Kurokawa, Katsuhide; Kajima, Takaki; Nakajima, Kazunori

2011-12-01

The positive effects of wearing a mouthguard have been indicated in various epidemiological surveys and experiments, and their usage appears to be increasing in many sports. However, many preventable sports-related dental injuries still occur even with the use of a conventional mouthguard. We have developed a mouthguard (the Hard & Space mouthguard) with sufficient injury prevention ability (more than 95% shock absorption ability against impact with a steel ball carrying 15.2 kg m(2) S(-2) potential energy) and ease of clinical application. This mouthguard consists of an outer and an inner EVA layer and a middle layer of acrylic resin (hard insert), with a space to prevent contact between the inner surface of the mouthguard and the buccal surfaces of the maxillary front teeth or teeth already weakened through prior damage or treatment. The purpose of this article is to describe the method by which the Hard & Space mouthguard may easily be fabricated. We believe that this new type of mouthguard has the potential to reduce sports-related dental injuries. © 2011 John Wiley & Sons A/S.

1. VIEW NORTH OF OLD POWERHOUSE (FOREGROUND) AND NEW POWERHOUSE ...

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

1. VIEW NORTH OF OLD POWERHOUSE (FOREGROUND) AND NEW POWERHOUSE (RIGHT BACKGROUND). RETAINING WALL WITH TAILRACE OUTLETS BELOW POWERHOUSES. TRANSFORMER YARD UPPER LEFT. ELEVATOR/STAIR TOWER OF NEW POWERHOUSE, WITH BRIDGE TO TOP OF GORGE, AT UPPER RIGHT CENTER, IN FRONT OF 1965 SURGE TANK. - Trenton Falls Hydroelectric Station, Powerhouse & Substation, On west bank of West Canada Creek, along Trenton Falls Road, 1.25 miles north of New York Route 28, Trenton Falls, Oneida County, NY

Spatial Distribution of Seismic Anisotropy in the Crust in the Northeast Front Zone of Tibetan Plateau

NASA Astrophysics Data System (ADS)

Gao, Y.; Wang, Q.; SHI, Y.

2017-12-01

There are orogenic belts and strong deformation in northeastern zone of Tibetan Plateau. The media in crust and in the upper mantle are seismic anisotropic there. This study uses seismic records by permanent seismic stations and portable seismic arrays, and adopts analysis techniques on body waves to obtain spatial anisotropic distribution in northeastern front zone of Tibetan Plateau. With seismic records of small local earthquakes, we study shear-wave splitting in the upper crust. The polarization of fast shear wave (PFS) can be obtained, and PFS is considered parallel to the strike of the cracks, as well as the direction of maximum horizontal compressive stress. However, the result shows the strong influence from tectonics, such as faults. It suggests multiple-influence including stress and fault. Spatial distribution of seismic anisotropy in study zone presents the effect in short range. PFS at the station on the strike-slip fault is quite different to PFS at station just hundreds of meters away from the fault. With seismic records of teleseismic waveforms, we obtained seismic anisotropy in the whole crust by receiver functions. The PFS directions from Pms receiver functions show consistency, generally in WNW. The time-delay of slow S phases is significant. With seismic records of SKS, PKS and SKKS phases, we can detect seismic anisotropy in the upper mantle by splitting analysis. The fast directions of these phases also show consistency, generally in WNW, similar to those of receiver functions, but larger time-delays. It suggests significant seismic anisotropy in the crust and crustal deformation is coherent to that in the upper mantle.Seismic anisotropy in the upper crust, in the whole crust and in the upper mantle are discussed both in difference and tectonic implications [Grateful to the support by NSFC Project 41474032].

Oral Health-Related Quality of Life in institutionalized elderly in Barcelona (Spain)

PubMed Central

Pérez, Glòria; de Lima, Kenio C.; Casals-Peidro, Elías; Borrell, Carme

2013-01-01

Objective: The objective of this study is to describe the oral health status and the factors associated with oral health-related quality of life (OHRQoL) in people aged 65 and older institutionalized in Barcelona in 2009. Study Design: Cross sectional study in 194 elderly. The dependent variable was poor OHRQoL, according to the Geriatric Oral Health Assessment Index (GOHAI). The independent variables were socio-demographic data, last dental visit, subjective and objective oral health status. Robust Poisson regression analysis was used to determine the factors associated with OHRQoL as well as the strengths of association (Prevalence Ratios with respective confidence intervals at 95%). Results: According to GOHAI, 94 women (68.1%) and 36 men (64.3%) had poor OHRQoL. The average DMFT index (number of decayed, missing and filled teeth) was 22.8, with mean 10.2 remaining teeth. According to the Community Periodontal Index only 1.9% were healthy. 33.8% of the sample (35.5% of women and 30.4% of men) presented edentulism, 54.2% needed upper dental prostheses (51.1% of women and 60.7% of men) and 64.7% needed lower ones (61.6% of women and 71.4% of men). Only 7.2% had visited a dentist in the past year (8.8% of women and 3.6% of men). After fitting several multivariate adjusted robust Poisson regression models, poor OHRQoL was found to be associated to self-reporting problems with teeth or gums, self-reporting poor opinion about teeth/gums/denture and also associated to functional edentulism, needing upper denture, but not to socio-demographic factors or time since last dental visit. Conclusions: The study population has poor objective oral health. A high percentage has poor OHRQoL associated to subjective and objective oral health conditions. Dental care is required and these services should be included in the Spanish National Health System. Key words:Oral health, homes for the aged, elderly, self-assessment, quality of life, geriatric oral health assessment index (GOHAI). PMID:23385501

Periodontal treatment with the frequency-doubled Alexandrite laser in dogs

NASA Astrophysics Data System (ADS)

Rechmann, Peter; Hennig, Thomas; Reichart, Peter

2000-03-01

While earlier periodontal investigations have proved the frequency doubled Alexandrite laser to eliminate efficiently and selectively dental calculus as well as bacteria the aim of this study was to demonstrate the safety of this laser for removal of dental calculus with respect to the dental pulp. Four adult Labrador dogs were treated with a frequency doubled Alexandrite laser (laboratory prototype, q-switched, fiber guided, wavelength 377 nm, pulse duration 1 microsecond, pulse repetition rate 70 Hz, water cooling) to remove dental calculus. After performing a modified Widman flap procedure the buccal surface of nine teeth in the lower and upper right jaw were irradiated for four minutes per tooth. Three different laser fluences up to four times higher than the fluence required for calculus removal were used (1.5, 3 and 6 J/cm2). At three other sites of the right jaw deep cavities were prepared with a dental drill and filled with compomere material (DyractR, Dentsply, Germany) to serve as a positive control with regard to possible pulpal reactions. The corresponding teeth of the lower and upper left jaw served as controls. Animals were sacrificed one day, one week, four weeks and six weeks after treatment. Teeth were separated, fixed in formalin and decalcified. After embedding and sectioning the histological sections were stained and investigated by a totally blinded investigator (P.A.R). Histological investigations revealed that irradiation with the frequency doubled Alexandrite laser for periodontal treatment with fluences of 1.5 J/cm2 -- those fluences necessary for the selective removal of dental calculus and microbial plaque -- had no adverse side effects to the pulpal tissues. Moreover this pulpal safety study demonstrated that even applying fluences two or four times higher than those suggested for calculus removal do not lead to observable changes or alterations in the odontoblast cell layer or the pulpal tissues. No inflammatory reactions and no differences between irradiated and control teeth occurred, while the positive controls showed reactions in the odontoblast cell layer and the connective pulpal tissue.

Work-related traumatic dental injuries: Prevalence, characteristics and risk factors.

PubMed

Ugolini, Alessandro; Parodi, Giovanni Battista; Casali, Claudia; Silvestrini-Biavati, Armando; Giacinti, Flavio

2018-02-01

The prevalence of work-related oral trauma is underestimated because minor dental injuries are often not reported in patients with several injuries in different parts of the body. In addition, little data are available regarding their characteristics. The aim of this epidemiological study was to determine the prevalence, types, and characteristics of occupational traumatic dental injuries (TDIs) in a large working community. Work-related TDIs that occurred during the period between 2011 and 2013 in the District of Genoa (Northwest of Italy, 0.86 million inhabitants) were analyzed. Patients' data were obtained from the National Institute for Insurance against Accidents at Work database. During the 2 year period, 112 TDIs (345 traumatized teeth) were recorded. The prevalence was 5.6‰ of the total amount of occupational trauma. The highest prevalence was found in the fourth and fifth decades of life (OR=3.6, P < .001), and males were injured more often than females (70.5% vs 29.5%, OR=2.8, P < .001). Service and office workers represented 52% of the sample, and construction/farm/factory workers and craftsmen were 48%. TDIs involved only teeth and surrounding tissue in 66% of cases, or in combination with another maxillofacial injury in 34%. They were statistically associated with construction/farm/factory workers group (Chi squared P < .01). Crown fracture was recorded in 34.5% of cases, subluxation/luxation in 10.7%, avulsion in 9%, root fracture in 3.8%, and concussion in 3.5%. Thirty-two subjects (28.6%, 133 teeth, OR=4.3, P < .001) presented at least 1 traumatized tooth with previous dental treatment. Among 212 (61.4%) traumatized teeth, 67.5% were upper incisors, 17.5% were lower incisors, 3.3% were upper canines, 1.9% were lower canines, and 9.9% were bicuspids and molars. Work-related TDIs had a low overall prevalence, and fractures were the most frequent dental injury. Age, gender, and preexisting dental treatments represented risk factors for work-related TDIs. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The influence of premature loss of temporary upper molars on permanent molars.

PubMed

Cernei, E R; Maxim, Dana Cristiana; Zetu, Irina Nicoleta

2015-01-01

Premature loss of primary molars due to dental caries and their complications has been associated with space loss and eruptive difficulties, especially when the loss occurs early. The aim of our study was to determine the impact of premature loss of temporary upper molars upon the longitudinal axis of the first and second upper permanent molar. The study group included 64 patients 6-9 years old with premature loss of primary molars and a control group of 48 patients with intact temporary teeth. It was evaluated the angle between longitudinal axis of first and second upper permanent molars and occlusal plane. The sofware used is Easy Dent 4 Viewer®.The data were analyzed by using the Statistical Package for the Social Sciences (version 20.0; SPSS, Chicago, III). It was observed that premature loss of upper second deciduous molars modifies greater the vertical axis of the permanent molars than the premature loss of first upper primary molar. First upper primary molar loss cause an acceleration eruption of first premolar, which will produce a distal inclintion of the both permanent molars. The use of space maintainers after premature loss of the second upper temporary molar is a last solution in preventing tridimensional lesions in the dental arch and occlusion.

Depositional environments of the Rock Springs Formation, southwest flank of the Rock Springs Uplift, Wyoming.

USGS Publications Warehouse

Kirschbaum, M.A.

1986-01-01

This deltaic Upper Cretaceous Rock Springs Formation of the Mesaverde Group was deposited during early Campanian time near the end of the regressive phase of the Niobrara cyclothem. On the southwest end of the Uplift, part of the delta system is exposed near the seaward edge of a series of transgressive/regressive sequences, which consist of intertonguing prodelta, delta-front, and delta-plain deposits. Eight major delta-front sandstones are vertically stacked and laterally continuous throughout the main study area.-from Author

50. VIEW OF CRUSHER ADDITION FROM EAST. SHOWS 100TON STEEL ...

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

50. VIEW OF CRUSHER ADDITION FROM EAST. SHOWS 100-TON STEEL UNOXIDIZED ORE BIN, STEPHENS-ADAMSON 15 TON/HR INCLINED BUCKET ELEVATOR, AND DUST COLLECTION BIN IN UPPER RIGHT QUADRANT. THE ROD MILL CIRCUIT STOOD IN FRONT OF THE BUCKET ELEVATOR AND BEHIND THE BAKER COOLER (LEFT CENTER). MILL SOLUTION TANKS WERE IN FRONT OF THE CRUSHED OXIDIZED ORE BIN (CENTER), AND THE MILL FLOOR WAS THE NEXT LEVEL DOWN (RIGHT). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Software Reviews.

ERIC Educational Resources Information Center

McGrath, Diane, Ed.

1989-01-01

Reviewed are two computer software programs for Apple II computers on weather for upper elementary and middle school grades. "Weather" introduces the major factors (temperature, humidity, wind, and air pressure) affecting weather. "How Weather Works" uses simulation and auto-tutorial formats on sun, wind, fronts, clouds, and…

Orthodontic treatment of the transposition of a maxillary canine and a first premolar: a case report.

PubMed

Teresa, Dinoi Maria; Stefano, Mummolo; Annalisa, Monaco; Enrico, Marchetti; Vincenzo, Campanella; Giuseppe, Marzo

2015-03-01

Transposition is an anomaly of tooth position, the most frequent of which involves the canine and the first maxillary premolar. We describe the orthodontic treatment of a unilateral transposition of an upper canine and an upper right first premolar in the permanent dentition. A 12-year-old Caucasian boy presented with transposition of his upper right canine and upper right first premolar. He had combined surgical-orthodontic treatment to correct the transposition and to obtain a Class I relationship between the molar and canine. This treatment resolved the dental crowding and achieved good functional and aesthetic results. In transposition, the choice of the most suitable treatment depends on the occlusion, level of dental crowding, aesthetics, position of the radicular apices, and the specific needs of the patient. In this case, orthodontic alignment of the transposed teeth into their physiological position achieved all of our objectives and our patient was satisfied with the aesthetic results obtained.

Multistate models of bigheaded carps in the Illinois River reveal spatial dynamics of invasive species

USGS Publications Warehouse

Coulter, Alison A.; Brey, Marybeth; Lubejko, Matthew; Kallis, Jahn L.; Coulter, David P.; Glover, David C.; Whitledge, Gregory W.; Garvey, James E.

2018-01-01

Knowledge of the spatial distributions and dispersal characteristics of invasive species is necessary for managing the spread of highly mobile species, such as invasive bigheaded carps (Bighead Carp [Hypophthalmichthys nobilis] and Silver Carp [H. molitrix]). Management of invasive bigheaded carps in the Illinois River has focused on using human-made barriers and harvest to limit dispersal towards the Laurentian Great Lakes. Acoustic telemetry data were used to parameterize multistate models to examine the spatial dynamics of bigheaded carps in the Illinois River to (1) evaluate the effects of existing dams on movement, (2) identify how individuals distribute among pools, and (3) gauge the effects of reductions in movement towards the invasion front. Multistate models estimated that movement was generally less likely among upper river pools (Starved Rock, Marseilles, and Dresden Island) than the lower river (La Grange and Peoria) which matched the pattern of gated versus wicket style dams. Simulations using estimated movement probabilities indicated that Bighead Carp accumulate in La Grange Pool while Silver Carp accumulate in Alton Pool. Fewer Bighead Carp reached the upper river compared to Silver Carp during simulations. Reducing upstream movement probabilities (e.g., reduced propagule pressure) by ≥ 75% into any of the upper river pools could reduce upper river abundance with similar results regardless of location. Given bigheaded carp reproduction in the upper Illinois River is presently limited, reduced movement towards the invasion front coupled with removal of individuals reaching these areas could limit potential future dispersal towards the Great Lakes.

Gross Anatomy of Pampas Deer (Ozotoceros bezoarticus, Linnaeus 1758) Mouth and Pharynx.

PubMed

Pérez, W; Vazquez, N; Ungerfeld, R

2017-04-01

The aims of this study were to describe the anatomy of the mouth and pharynx of the pampas deer, and to consider its evolutionary feeding niche according to those characteristics. Gross dissections of the mouth and pharynx were performed in 15 animals, 10 adult females and five young animals under 1 year (three males and two females), all dead by causes unrelated to this anatomical region. The upper lip entered in the constitution of a pigmented nasolabial plane. The masseter muscles weighed 43.8 ± 3.5 g and represented 0.23% of body weight, which corresponds to ruminants of feeders intermediate to grazers and browsers. Parotid glands represented 0.08% of the body weight, characteristic that also categorize the pampas deer as belonging to the intermediate feeding group. The dental formula was the same of the domestic ruminants. The upper incisors and canines were absent, and instead of them, there was a dental pad (Pulvinus dentalis). The upper canine teeth were present only in the deciduous dentition. The existence of a brachydont dentition turns Ozotoceros very vulnerable to continuous use as there is no compensatory teeth growth. The particular anatomy of the mouth and lips of this animal was adapted to a very selective feeding, taking highly nutritious sprouts beyond plant category. In conclusion and in addition to previous studies of anatomy of the digestive organs in this species, pampas deer may be categorized as belonging to the intermediate type of feeding. © 2016 Blackwell Verlag GmbH.

Unpredictability of soft tissue changes after camouflage treatment of Class II division 1 malocclusion with maximum anterior retraction using miniscrews.

PubMed

Kim, Kayoung; Choi, Sung-Hwan; Choi, Eun-Hee; Choi, Yoon-Jeong; Hwang, Chung-Ju; Cha, Jung-Yul

2017-03-01

To compare soft and hard tissue responses based on the degree of maxillary incisor retraction using maximum anchorage in patients with Class II division 1 malocclusion. This retrospective study sample was divided into moderate retraction (<8.0 mm; n = 28) and maximum retraction (≥8.0 mm; n = 29) groups based on the amount of maxillary incisor retraction after extraction of the maxillary and mandibular first premolars for camouflage treatment. Pre- and posttreatment lateral cephalograms were analyzed. There were 2.3 mm and 3.0 mm of upper and lower lip retraction, respectively, in the moderate group; and 4.0 mm and 5.3 mm, respectively, in the maximum group. In the moderate group, the upper lip was most influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.94). The lower lip was most influenced by posterior movement of B-point (β = 0.84) and the cervical point of the mandibular incisor (β = 0.83). Prediction was difficult in the maximum group; no variable showed a significant influence on upper lip changes. The lower lip was highly influenced by posterior movement of the cervical point of the maxillary incisor (β = 0.50), but this correlation was weak in the maximum group. Posterior movement of the cervical point of the anterior teeth is necessary for increased lip retraction. However, periodic evaluation of the lip profile is needed during maximum retraction of the anterior teeth because of limitations in predicting soft tissue responses.

Brief communication: dental development timing in captive Pan paniscus with comparisons to Pan troglodytes.

PubMed

Bolter, Debra R; Zihlman, Adrienne L

2011-08-01

Dental eruption provides markers of growth and is one component of a chimpanzee's physical development. Dental markers help characterize transitions between life stages, e.g., infant to juvenile. Most of what we know about the timing of development in chimpanzees derives from Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a restricted wild range in central Africa. Here we report on the dental eruption timing for female captive P. paniscus (n = 5) from the Milwaukee and San Diego Zoos whose ages are known and range from birth to age 8.54 years. Some observations were recorded in zoo records on the gingiva during life; others were made at death on the gingiva and on the skeleton. At birth, P. paniscus infants have no teeth emerged. By 0.83 years, all but the deciduous second molars (dm(2) ) (when both upper and lower dentitions are referenced collectively, no super or subscript notation is used) and canines (dc) are emerged. For permanent teeth, results show a sequence polymorphism for an early P4 eruption, not previously described for P. paniscus. Comparisons between P. paniscus and P. troglodytes document absolute timing differences of emergence in upper second incisors (I(2) ), and upper and lower canines (C) and third molars (M3). The genus Pan encompasses variability in growth not previously recognized. These preliminary data suggest that physical growth in captive P. paniscus may be accelerated, a general pattern found in captive P. troglodytes. Copyright © 2011 Wiley-Liss, Inc.

Salinity Processes in the Upper Ocean Regional Study (SPURS)

NASA Image and Video Library

2012-09-04

Woods Hole Oceanographic Institution Senior Scientist Ray Schmitt, left, and NASA Physical Oceanography Program Scientist Eric Lindstrom pose for a photograph in front of the Institution's research vessel Knorr on Tuesday, Sept. 4, 2012, in Woods Hole, Mass. Knorr is scheduled to depart on Sept. 6 to take part in the Salinity Processes in the Upper Ocean Regional Study (SPURS). The NASA-sponsored expedition will sail to the North Atlantic's saltiest spot to get a detailed, 3-D picture of how salt content fluctuates in the ocean's upper layers and how these variations are related to shifts in rainfall patterns around the planet. Photo Credit: (NASA/Bill Ingalls)

Upper bound on the efficiency of certain nonimaging concentrators in the physical-optics model

NASA Astrophysics Data System (ADS)

Welford, W. T.; Winston, R.

1982-09-01

Upper bounds on the performance of nonimaging concentrators are obtained within the framework of scalar-wave theory by using a simple approach to avoid complex calculations on multiple phase fronts. The approach consists in treating a theoretically perfect image-forming device and postulating that no non-image-forming concentrator can have a better performance than such an ideal image-forming system. The performance of such a system can be calculated according to wave theory, and this will provide, in accordance with the postulate, upper bounds on the performance of nonimaging systems. The method is demonstrated for a two-dimensional compound parabolic concentrator.

Prosthetic treatment of oligodontia with a tooth-supported overdenture--a case report.

PubMed

Akeredolu, P A

2002-01-01

An unusual case of oligodontia is reported in a 20 year old Nigerian male. It is unusual because of the isolated occurrence of the oligodontia which is unassociated with a family history or any other clinical features suggestive of specific syndromes or severe systemic abnormality. The patient presented with conically or peg shaped anterior and malformed posterior teeth in both the maxilla and mandible. Full mouth periapical radiographs revealed stunted roots, widening of the periodontal space and an unerupted tooth in the right mandibular premolar region. Tooth-supported upper and lower removable partial overdenture were fabricated for him. This modality of treatment is a better choice which helps not only to preserve the alveolar ridge height and improve aesthetics, but also preserves the proprioceptive mechanisms associated with the periodontal membrane of natural teeth.

Abscesses of the frontal lobe of the brain secondary to covert dental sepsis.

PubMed

Ingham, H R; Kalbag, R M; Tharagonnet, D; High, A S; Sengupta, R P; Selkon, J B

1978-09-02

The bacterial species found in pus aspirated from brain abscesses in two patients were typical of those found in dental sepsis. Subsequently apical-root abscesses were demonstrated in the upper jaws of both patients. This evidence strongly suggests that these cerebral abscesses were secondary to dental sepsis which could have spread from the teeth to the frontal lobes by several possible antaomical pathways.

Is the smile line a valid parameter for esthetic evaluation? A systematic literature review.

PubMed

Passia, Nicole; Blatz, Markus; Strub, Jörg Rudolf

2011-01-01

The "smile line" is commonly used as a parameter to evaluate and categorize a person's smile. This systematic literature review assessed the existing evidence on the validity and universal applicability of this parameter. The latter was evaluated based on studies on smile perception by orthodontists, general clinicians, and laypeople. A review of the literature published between October 1973 and January 2010 was conducted with the electronic database Pubmed and the search terms "smile," "smile line," "smile arc," and "smile design." The search yielded 309 articles, of which nine studies were included based on the selection criteria. The selected studies typically correlate the smile line with the position of the upper lip during a smile while, on average, 75 to 100% of the maxillary anterior teeth are exposed. A virtual line that connects the incisal edges of the maxillary anterior teeth commonly follows the upper border of the lower lip. Average and parallel smile lines are most common, influenced by the age and gender of a person. Orthodontists, general clinicians, and laypeople have similar preferences and rate average smile lines as most attractive. The smile line is a valid tool to assess the esthetic appearance of a smile. It can be applied universally as clinicians and laypersons perceive and judge it similarly.

Four impacted fourth molars in a young patient: a case report

PubMed Central

CLEMENTINI, M.; OTTRIA, L.; PANDOLFI, C.; AGRESTINI, C.; BARLATTANI, A.

2013-01-01

Summary The occurrence of supernumerary teeth is a relatively uncommon dental anomaly and it’s rare for patients to have impacted fourth molars in all quadrant. Aim of this work is to describe the presence of bilateral fourth molars in the maxilla and the mandible in a young male patient aged 22 years came to our hospital with acute pericoronal infection around unerupted third inferior molars. Routine radiographic examination revealed impacted inferior third molars but also unerupted bilateral upper and inferior fourth molars. The acute infection was treated by local measures and the patient was subsequently admitted for removal of third and fourth impacted upper and lower molars under general anesthesia. PMID:23741604

Division of labor by sex and age in Neandertals: an approach through the study of activity-related dental wear.

PubMed

Estalrrich, Almudena; Rosas, Antonio

2015-03-01

The analysis of activity-related dental wear patterns in prehistoric anatomically modern humans and modern hunter-gatherers has shown sex differences attributable to a gendered division of labor. Neandertals are known to have extensive anterior dental wear related to the use of their front teeth as a tool. In this study we analyze the i) cultural striations (scratches on the labial surface of the anterior teeth with a cut-mark morphology), and ii) dental chipping (ante-mortem microfracture involving enamel or both enamel and dentine) in 19 Neandertal individuals from the l'Hortus (France), Spy (Belgium), and El Sidrón (Spain) sites, and compare the characteristics of those traits with the age and sex estimation for the individuals and among samples. The study reveals that all individuals have cultural striations, but those detected on the adult females are longer than the striations found in adult males. Regarding the distribution of dental chipping, the prevalence of this trait is higher in the maxillary dentition of males whereas females have the majority of dental chipping on their mandibular teeth. The differences detected on the overall activity-related dental wear pattern denote a difference or a division of labor by age and sex in Neandertals while using the mouth as a third hand, i.e., in activities other than the provisioning of food, and provide new evidence for the lifestyle of this Pleistocene fossil human species. Copyright © 2014 Elsevier Ltd. All rights reserved.

20. NBS SUIT LAB. TABLE WITH MISCELLANEOUS SUIT PARTS AND ...

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

20. NBS SUIT LAB. TABLE WITH MISCELLANEOUS SUIT PARTS AND TERRY WEST, A SPACE SUIT ASSEMBLY TECHNICIAN LOGGING SUIT PART DATA. PARTS ON THE TABLE ARE A HARD UPPER TORSO (HUT) (REAR LEFT), FULL HELMET (FRONT LEFT), TWO HELMETS WITHOUT PROTECTIVE VISORS, A PAIR OF GLOVES, AND A BACKPACK WITHOUT VOLUMETRIC COVER (REAR RIGHT). THE BACKPACK ATTACHES TO THE HUT TO MAKE-UP THE UPPER TORSO COMPONENTS OF THE SUIT. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

Magnetotelluric Imaging of Lower Crustal Melt and Lithospheric Hydration in the Rocky Mountain Front Transition Zone, Colorado, USA

NASA Astrophysics Data System (ADS)

Feucht, D. W.; Sheehan, A. F.; Bedrosian, P. A.

2017-12-01

We present an electrical resistivity model of the crust and upper mantle from two-dimensional (2-D) anisotropic inversion of magnetotelluric data collected along a 450 km transect of the Rio Grande rift, southern Rocky Mountains, and High Plains in Colorado, USA. Our model provides a window into the modern-day lithosphere beneath the Rocky Mountain Front to depths in excess of 150 km. Two key features of the 2-D resistivity model are (1) a broad zone ( 200 km wide) of enhanced electrical conductivity (<20 Ωm) in the midcrust to lower crust that is centered beneath the highest elevations of the southern Rocky Mountains and (2) hydrated lithospheric mantle beneath the Great Plains with water content in excess of 100 ppm. We interpret the high conductivity region of the lower crust as a zone of partially molten basalt and associated deep-crustal fluids that is the result of recent (less than 10 Ma) tectonic activity in the region. The recent supply of volatiles and/or heat to the base of the crust in the late Cenozoic implies that modern-day tectonic activity in the western United States extends to at least the western margin of the Great Plains. The transition from conductive to resistive upper mantle is caused by a gradient in lithospheric modification, likely including hydration of nominally anhydrous minerals, with maximum hydration occurring beneath the Rocky Mountain Front. This lithospheric "hydration front" has implications for the tectonic evolution of the continental interior and the mechanisms by which water infiltrates the lithosphere.

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

PubMed

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

2016-07-01

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

Early Pleistocene hominin deciduous teeth from the Homo antecessor Gran Dolina-TD6 bearing level (Sierra de Atapuerca, Spain).

PubMed

Bermúdez de Castro, José María; Martinón-Torres, María; Martín-Francés, Laura; Martínez de Pinillos, Marina; Modesto-Mata, Mario; García-Campos, Cecilia; Wu, Xiujie; Xing, Song; Liu, Wu

2017-07-01

During the last 13 years, the late Early Pleistocene Gran Dolina-TD6-2 level (Sierra de Atapuerca, northern Spain) has yielded an additional sample of 26 dental specimens attributed to Homo antecessor. In this report, we present a descriptive and comparative study of the six deciduous teeth. We provide external and internal morphological descriptions following classical terminology, as well as the mesiodistal and buccolingual measurements of the teeth. The internal morphology was described by means of micro-CT technique. The TD6 deciduous teeth preserve primitive features regarding the Homo clade, such as the presence of styles in lower and upper canines and developed anterior and posterior foveae in the dm 2 . However, other features related to the complexity of the crown morphology (e.g., cingulum) are not present in this sample. Furthermore, the great reduction of the talonid of the dm 1 s is also noteworthy. Despite the limited comparative evidence, the presence of a remarkably well-developed tuberculum molare in the dm 1 and dm 1 s from TD6 can be also considered a derived feature in the genus Homo. The TD6 hominins exhibit dental dimensions similar to those of other Pleistocene hominins. The dm 1 s are buccolingually elongated and the buccolingual diameter of ATD6-93 is the largest recorded so far in the Homo fossil record. This study expands the list of plesiomorphic features of H. antecessor, and provides some information on the evolutionary status of this species. However, the identification of some advanced traits evinces a step towards the derived morphology of European Pleistocene teeth. The study of the deciduous dentition confirms the mosaic pattern of H. antecessor morphology revealed in previous studies of this hominin sample. © 2017 Wiley Periodicals, Inc.

Root resorption during orthodontic treatment with Invisalign®: a radiometric study.

PubMed

Gay, Giulia; Ravera, Serena; Castroflorio, Tommaso; Garino, Francesco; Rossini, Gabriele; Parrini, Simone; Cugliari, Giovanni; Deregibus, Andrea

2017-12-01

Root resorption (RR) is described as a permanent loss of tooth structure from the root apex. Many reports in the literature indicate that orthodontically treated patients are more likely to have severe apical root shortening, interesting mostly maxillary, followed by mandibular incisors. The aim of the study was to investigate the incidence and severity of RR in adult patients treated with aligners. The study group consisted of 71 class I adult healthy patients (mean age 32.8 ± 12.7) treated with aligners (Invisalign®, Align Technologies, Santa Clara, CA, USA). All incisors, canines, upper first premolars, and first molars were assessed. Root and crown lengths of 1083 teeth were measured in panoramic radiographs at the beginning (T0) and at the end (T1) of clear aligner therapy. Individual root-crown ratio (RCR) of each tooth and therefore the relative changes of RCR (rRCR) were determined. A decrease of rRCR was assessed as a reduction of the root length during treatment. All patients had a minimum of one teeth affected with a reduction of root length, on average 6.38 ± 2.28 teeth per patient. Forty one, 81% of the 1083, measured teeth presented a reduction of the pre-treatment root length. A reduction in percentage of >0% up to 10% was found in 25.94% (n = 281), a distinct reduction of >10% up to 20% in 12.18% (n = 132) of the sample. 3.69% (n = 40) of the teeth were affected with a considerable reduction (>20%). Orthodontic treatment with Invisalign® aligners could lead to RR. However, its incidence resulted to be very similar to that described for orthodontic light forces, with an average percentage of RR < 10% of the original root length.

Early Childhood Caries: A Review.

PubMed

Alazmah, Abdulfatah

2017-08-01

To review and update the current knowledge about early childhood caries (ECC) and its etiology, prevalence, risk factors, management, and preventive strategies. Early childhood caries is a disease affecting significantly both well-developed and industrial nations. The ECC can significantly affect the child's quality of life, as it may lead to infection, swelling, pain, and other symptoms. The ECC affects children after eruption of primary teeth until age of around 5 years. The ECC affects all parts of the tooth including the smooth surface. Upper anterior teeth and primary molars are usually affected. The lower anterior teeth are less likely affected. The risk factors for ECC are diet, bacteria, and host susceptibility. The additional factors, such as presence of enamel defect and the feeding practices also contribute to the initiation and progress of ECC. Dentists must focus on utilizing existing techniques to distinguish indications of right on time and propelled caries and give guidance on the best way to counteract and control caries in children. Approaches should be directed to preventive caries control strategies among children. Preventing and controlling the development of ECC among children is important to maintain effective eating, speech development, and formation of a positive self-image.

Modern mammal origins: evolutionary grades in the Early Cretaceous of North America.

PubMed Central

Jacobs, L L; Winkler, D A; Murry, P A

1989-01-01

Major groups of modern mammals have their origins in the Mesozoic Era, yet the mammalian fossil record is generally poor for that time interval. Fundamental morphological changes that led to modern mammals are often represented by small samples of isolated teeth. Fortunately, functional wear facets on teeth allow prediction of the morphology of occluding teeth that may be unrepresented by fossils. A major step in mammalian evolution occurred in the Early Cretaceous with the evolution of tribosphenic molars, which characterize marsupials and placentals, the two most abundant and diverse extant groups of mammals. A tooth from the Early Cretaceous (110 million years before present) of Texas tests previous predictions (based on lower molars) of the morphology of upper molars in early tribosphenic dentitions. The lingual cusp (protocone) is primitively without shear facets, as expected, but the cheek side of the tooth is derived (advanced) in having distinctive cusps along the margin. The tooth, although distressingly inadequate to define many features of the organism, demonstrates unexpected morphological diversity at a strategic stage of mammalian evolution and falsifies previous claims of the earliest occurrence of true marsupials. Images PMID:2740336

Experimental and numerical investigation of the sound generation mechanisms of sibilant fricatives using a simplified vocal tract model

NASA Astrophysics Data System (ADS)

Yoshinaga, Tsukasa; Nozaki, Kazunori; Wada, Shigeo

2018-03-01

The sound generation mechanisms of sibilant fricatives were investigated with experimental measurements and large-eddy simulations using a simplified vocal tract model. The vocal tract geometry was simplified to a three-dimensional rectangular channel, and differences in the geometries while pronouncing fricatives /s/ and /∫/ were expressed by shifting the position of the tongue and its constricted flow channel. Experimental results showed that the characteristic peak frequency of the fricatives decreased when the distance between the tongue and teeth increased. Numerical simulations revealed that the jet flow generated from the constriction impinged on the upper teeth wall and caused the main sound source upstream and downstream from the gap between the teeth. While magnitudes of the sound source decreased with increments of the frequency, amplitudes of the pressure downstream from the constriction increased at the peak frequencies of the corresponding tongue position. These results indicate that the sound pressures at the peak frequencies increased by acoustic resonance in the channel downstream from the constriction, and the different frequency characteristics between /s/ and /∫/ were produced by changing the constriction and the acoustic node positions inside the vocal tract.

A rare case report and appraisal of the literature on spontaneous tooth exfoliation associated with trigeminal herpes zoster.

PubMed

Kaur, Rupinder; Rani, Pooja; Malhotra, Divye; Kaur, Rajwant; Dass, Praveen Kumar

2016-09-01

Reports of post herpetic maxillofacial complications have been very rarely documented in the literature that includes periapical lesions, calcified and devitalized pulps, resorption of roots, osteonecrosis, and spontaneous exfoliation of teeth. The atypical feature of the case of concern to the dental surgeon is the rare complication of spontaneous tooth exfoliation following herpes zoster. This case reports a male patient of age 47 years who reported to the Department of Periodontology with the chief complaint of mobility in the left upper central incisor. Patient history revealed herpes zoster infection that began 11 days earlier along with underlying diabetes mellitus condition. We hereby report a known diabetic patient with history of herpes zoster infection who presented with rare complication of spontaneous tooth exfoliation involving the maxillary division of the trigeminal nerve. Limited number of cases has been reported in the literature regarding spontaneous teeth exfoliation secondary to herpes zoster. The exact pathogenesis regarding the spontaneous exfoliation of teeth in herpes zoster patient is still controversial. Thus, an oral health care provider should be aware of this rare complication while managing a case of tooth mobility with the previous history of herpes zoster of trigeminal nerve.

The stereognostic ability of natural dentitions versus implant-supported fixed prostheses or overdentures.

PubMed

Jacobs, R; Bou Serhal, C; van Steenberghe, D

1997-06-01

A stereognostic ability test was performed in 60 patients. Forty patients were rehabilitated by means of osseointegrated implants. One group consisted of 20 patients with fixed prostheses on implants in both the upper and lower jaws. The other 20 patients had a maxillary denture while in the mandible an overdenture was retained by means of two implants connected by a bar. They were compared to a group of 20 subjects (controls) with a non-restored natural dentition. For the stereognostic ability test, subjects had to recognise ten different test pieces by manipulating them with two antagonistic incisor teeth, avoiding any contact with other oral structures. Both response time and percentage accuracy of recognition were evaluated. The present findings indicated that subjects with an overdenture on implants did not score significantly different from those with an implant-supported fixed prosthesis. In contrast, subjects with teeth had a significantly better stereognostic ability. The percentage of correct responses was 52% for overdentures, 56% for fixed prostheses on implants and 75% for natural dentitions. From these results, it could be concluded that the stereognostic ability is impaired in subjects rehabilitated with osseointegrated implants by about one-third to one-quarter compared to subjects with natural teeth.

Removable orthodontic appliances: new perspectives on capabilities and efficiency.

PubMed

Hamid Zafarmand, A; Mahdi Zafarmand, M

2013-06-01

Removable appliances are a dependable choice for many patients but like all orthodontic appliances, they have some limitations in use. Patient selection and appropriate appliance design are two key factors for success. Many patients, especially adults, prefer intra-oral appliances to extra-oral devices. Sometimes a removable intra-oral appliance can solve a dental problem in a shorter period of time compared to fixed treatment, and this has also been repeatedly seen in molar distalisation. From the interceptive perspective, the appliance can prevent or alleviate an impending crowding for erupting permanent incisors. This article describes 5 patients with different orthodontic problems: impending crowding for erupting upper canine with 2 approaches, provision of space for upper cuspids, resolution of chronic attrition of anterior teeth, relief of space shortage for upper canines eruption, and reduction of excess overjet. All subjects were treated with removable appliances of various designs.

[Pre-surgical orthodontic treatment of skeletal class II patients with gingival smile corrected by anterior maxillary segmental osteotomy].

PubMed

Li, Xiaobing; Xiao, Liwei; Chen, Song; Chen, Yangxi

2002-11-01

To discuss the pre-surgical orthodontic treatment of skeletal class II patients with gingiva smile corrected by AMSO. We analyzed the clinical features of 20 skeletal class II patients treated by AMSO combined with Orthodontic treatment and evaluated the effects of AMSO by means of cephalometric analysis. After the AMSO treatment, ANB angle, the height of anterior maxilla, the protrusion of the upper anterior teeth, and the of A point had reduced significantly (P < 0.05). After AMSO, the appearance of patients had been improved markedly. AMSO can correct the protrusion of the maxilla and gingival smie efficiently. The anchorage of molars should be controlled carefully. The anterior part of the upper arch should be expended orthodontically to make arch relationship. Extract the upper bicuspid half a year before the surgery was recommended. When necessary, genioplasty could be performed.

An analysis of selected cases of derecho in Poland

NASA Astrophysics Data System (ADS)

Celiński-Mysław, Daniel; Matuszko, Dorota

2014-11-01

The paper analyses six cases of the derecho phenomena, which occurred in Poland between 2007 and 2012. The input data included reports on dangerous meteorological phenomena, SYNOP and METAR reports, MSL pressure maps, upper air maps at 500 hPa and 850 hPa, radar depictions and satellite images, upper air sounding plots and data from a system locating atmospheric discharges. Derechos are caused directly by the activity of mesoscale convective systems linked up with either, in winter, a cold front of a deep low-pressure system, or, in summer, with an area of wind convergence in a warm sector of a cyclone or with an articulated cold front which, moving within a low-pressure embayment, develops a very active secondary depression. It was found that southern and central Poland were the regions most frequently affected by derechos. Mid-level and high-level jet streams, augmented by high thermodynamic instability of air masses, were found to be conducive to the development of derechos.

DETAIL VIEW OF WINCHING ENGINE LOCATED AT THE UPPER TRAM ...

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

DETAIL VIEW OF WINCHING ENGINE LOCATED AT THE UPPER TRAM TERMINAL, LOOKING NORTHEAST. THE CABLE FROM THIS ENGINE LEADS DOWN INTO THE DEEP RAVINE IN FRONT OF THE UPPER TRAM TERMINAL. IT WAS PROBABLY USED TO DRAG MATERIALS UP TOWARD THE TERMINAL WHEN THE TERMINAL WAS BEING CONSTRUCTED, OR IN TIMES OF TRAMWAY BREAKDOWN. THE DRIVE ENGINE IS IN THE BACKGROUND. TWO LONG OPERATING LEVERS FOR THE ENGINE ARE IN THE CENTER FOREGROUND. AN EXTRA SPOOL OF CABLE IS ON THE GROUND TO THE RIGHT OF THE ENGINE. A WATER PIPELINE STRETCHES ACROSS THE SLOPE IN THE BACKGROUND, CARRYING WATER TO THE UPPER MINES. SEE CA-291-37 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

DETAIL VIEW OF WINCHING ENGINE LOCATED AT THE UPPER TRAM ...

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

DETAIL VIEW OF WINCHING ENGINE LOCATED AT THE UPPER TRAM TERMINAL LOOKING NORTHEAST. THE CABLE FROM THIS ENGINE LEADS DOWN INTO THE DEEP RAVINE IN FRONT OF THE UPPER TRAM TERMINAL. IT WAS PROBABLY USED TO DRAG MATERIALS UP TOWARD THE TERMINAL WHEN THE TERMINAL WAS BEING CONSTRUCTED, OR IN TIMES OF TRAMWAY BREAK DOWN. THE DRIVE ENGINE IS IN THE BACKGROUND. TWO LONG OPERATING LEVERS FOR THE ENGINE ARE IN THE CENTER FOREGROUND. AN EXTRA SPOOL OF CABLE IS ON THE GROUND TO THE RIGHT OF THE ENGINE. A WATER PIPELINE STRETCHES ACROSS THE SLOPE IN THE BACKGROUND, CARRYING WATER TO THE UPPER MINES. SEE CA-291-52 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

Present and future in the use of micro-CT scanner 3D analysis for the study of dental and root canal morphology.

PubMed

Grande, Nicola M; Plotino, Gianluca; Gambarini, Gianluca; Testarelli, Luca; D'Ambrosio, Ferdinando; Pecci, Raffaella; Bedini, Rossella

2012-01-01

The goal of the present article is to illustrate and analyze the applications and the potential of microcomputed tomography (micro-CT) in the analysis of tooth anatomy and root canal morphology. The authors performed a micro-CT analysis of the following different teeth: maxillary first molars with a second canal in the mesiobuccal (MB) root, mandibular first molars with complex anatomy in the mesial root, premolars with single and double roots and with complicated apical anatomy. The hardware device used in this study was a desktop X-ray microfocus CT scanner (SkyScan 1072, SkyScan bvba, Aartselaar, Belgium). A specific software ResolveRT Amira (Visage Imaging) was used for the 3D analysis and imaging. The authors obtained three-dimensional images from 15 teeth. It was possible to precisely visualize and analyze external and internal anatomy of teeth, showing the finest details. Among the 5 upper molars analyzed, in three cases, the MB canals joined into one canal, while in the other two molars the two mesial canals were separate. Among the lower molars two of the five samples exhibited a single canal in the mesial root, which had a broad, flat appearance in a mesiodistal dimension. In the five premolar teeth, the canals were independent; however, the apical delta and ramifications of the root canals were quite complex. Micro-CT offers a simple and reproducible technique for 3D noninvasive assessment of the anatomy of root canal systems.

Increasing volume of vestibular soft tissues in flapless implant surgery through a modified connective punch technique: a controlled clinical trial

PubMed Central

BASSI, M. ANDREASI; ANDRISANI, C.; LICO, S.; SILVESTRE, F.; GARGARI, M.; ARCURI, C.

2016-01-01

SUMMARY Purpose The aim of this article is to make a comparative assessment between the modification of the soft-tissue profile, around the healing cap screws (HCSs), following both the traditional flapless surgery (TFS) and a new modified flapless surgery, named Modified Connective Tissue Punch (MCTP) technique. Materials and methods 8 patients (3M and 5F) (mean age 54.25±11.247 years) were enrolled in this study. Sixteen two-piece implants were placed on upper jaws, 2 for each patient, 8 with TFS and 8 with MCTP technique. In each patient the implants were placed in edentulous areas, of 2 or 3 adjacent teeth long. MCTP technique was performed on the front implant site (FIS) while the TFS was performed on the rear implant site (RIS). All implants were inserted and covered with healing cap screws (HCSs). Alginate impressions were carried out at the moment of the surgery, at 1 month and 4 months post-operative. Plaster models were poured and subsequently digitally scanned, in order to measure the distance between the gingival outline and the free margin of the HCS. The recorded values were analyzed with the ANOVA test. Results The use of MTCP technique, in comparison to TFS, showed a significative better outcome, in terms of vertical increments, of gingiva, on the VS toward the HCSs, during the entire observation period (p = 0.000 for all). Conclusion The Authors recommend the use of MCTP technique for a better vestibular soft tissue outcome in flapless implant surgery. PMID:28042442

Impact of Dental Fluorosis, Socioeconomic Status and Self-Perception in Adolescents Exposed to a High Level of Fluoride in Water

PubMed Central

Molina-Frechero, Nelly; Nevarez-Rascón, Martina; Nevarez-Rascón, Alfredo; González-González, Rogelio; Irigoyen-Camacho, María Esther; Sánchez-Pérez, Leonor; López-Verdin, Sandra; Bologna-Molina, Ronell

2017-01-01

Objective: To identify adolescents’ self-perception of dental fluorosis from two areas with different socioeconomic levels. Methods: A cross-sectional, descriptive study was conducted with 15-year-old youths by applying a questionnaire designed and validated to assess self-perceptions of dental fluorosis in two areas with different socioeconomic statuses (SESs). Fluorosis was clinically evaluated by applying the Thylstrup and Fejerkov (TF) index on the upper front teeth. Results: A total of 308 adolescents were included in the study. The medium-SES population, which was exposed to 2.5 ppm of fluoride in water, and the low-SES population, which was exposed to 5.1 ppm, presented the following levels of dental fluorosis: TF 2–3 (50%), TF 4–5 (45.6%) and TF 6–7 (4.4%) for medium SES and TF 2–3 (12.3%), TF 4–5 (67.1%) and TF 67 (20.6%) for low SES. A significant association was found between self-perception and dental fluorosis in those with medium and low SESs (p < 0.05). The multiple regression model found differences between TF levels and self-perception, with a 6–7 TF level for concerns about color (OR = 1.6), smile (OR = 1.2) and appearance (OR = 3.36). Conclusions: Self-perceptions of dental fluorosis affect adolescents such that adolescents with a medium SES have more negative perceptions than those with a low SES. Such perceptions increase as the TF index increases. PMID:28085102

Distribution patterns of the mesozooplankton, principally siphonophores and medusae, in the vicinity of the Antarctic Slope Front (eastern Weddell Sea)

NASA Astrophysics Data System (ADS)

Pagès, Francesc; Schnack-Schiel, Sigrid B.

1996-12-01

The composition, abundance and vertical distribution of mesozooplankton, particularly siphonophores and medusae (27 species), collected along two transects in the eastern Weddell Sea have been analysed. Both transects were characterized by a steep thermocline that on approaching the coastline defined the Antarctic Slope Front. The front acted as a strong boundary in the shelf-slope and caused a pronounced cross frontal gradient in the populations of cnidarians. Few species and low abundances were found in the upper cold waters and most of the populations concentrated in and below the thermocline. The analysis of the gastrozooids of the physonect siphonophore Pyrostephos vanhoeffeni showed a wide variety of prey but the relatively high contribution of krill larvae reveals a substantial trophic impact when both organisms co-occur.

Esthetic Rehabilitation of the Smile with No-Prep Porcelain Laminates and Partial Veneers

PubMed Central

Farias-Neto, Arcelino; Gomes, Edna Maria da Cunha Ferreira; Sánchez-Ayala, Alfonso; Sánchez-Ayala, Alejandro; Vilanova, Larissa Soares Reis

2015-01-01

Rehabilitation of patients with anterior conoid teeth may present a challenge for the clinician, especially when trying to mimic the nature with composite resins. This clinical report exemplifies how a patient with conoid upper lateral incisors was rehabilitated with minimally invasive adhesive restorations. Following diagnostic wax-up and cosmetic mock-up, no-prep veneers and ceramic fragments (partial veneers) were constructed with feldspathic porcelain. This restorative material presents excellent reproduction of the optical properties of the dental structure, especially at minimal thicknesses. In this paper, the details about the treatment are described. A very pleasing outcome was achieved, confirming that minimally invasive adhesive restorations are an excellent option for situations in which the dental elements are healthy, and can be modified exclusively by adding material and the patient does not want to suffer any wear on the teeth. PMID:26568893

Sex differences in Hadza dental wear patterns : a preliminary report.

PubMed

Berbesque, J Colette; Marlowe, Frank W; Pawn, Ian; Thompson, Peter; Johnson, Guy; Mabulla, Audax

2012-09-01

Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools.

Maxillary overlay removable partial dentures for the restoration of worn teeth.

PubMed

Fonseca, Júlio; Nicolau, Pedro; Daher, Tony

2011-04-01

Prolonged tooth maintenance by a more aged population considerably increases the probability of dentists having to treat patients with high levels of tooth wear. Pathological tooth wear, caused primarily by parafunction, seems to be a growing problem that affects a large number of adult patients. The clinical report presents a case of a partially edentulous patient with an elevated degree of wear in the upper jaw caused by attrition and erosion, rehabilitated with a maxillary overlay removable partial denture (ORPD) consisting of a chrome-cobalt (Cr-Co) framework with anterior acrylic resin veneers, posterior cast overlays, and acrylic resin denture bases. Removable partial prosthesis is a treatment alternative when teeth are found to be severely worn or when the patient needs a simple and economical option. Because economics is a conditional factor of the treatment, the clinician should present different treatment alternatives to the patient, in which the overlay prosthesis can be considered.

Telescopic overdenture for oral rehabilitation of ectodermal dysplasia patient.

PubMed

Gupta, Charu; Verma, Mahesh; Gupta, Rekha; Gill, Shubhra

2015-09-01

Reduced number of teeth with underdeveloped alveolar ridges poses a greatest prosthetic challenge in rehabilitation of ectodermal dysplasia patients (ED). Furthermore, surgical risks and financial constraints may preclude the implant supported prosthesis, the most desirable treatment option in an adult ED patient. Long edentulous span does not permit fixed dental prosthesis (FDP) as well. Telescopic denture by incorporating the best of both fixed and removable prosthesis can be a viable treatment alternative for ED patients with compromised dentition and limited finances. A 21-year-old young girl presented with chief complaint of esthetics and mastication due to missing upper and lower teeth. A provisional diagnosis of ED was made based on familial history, physical, and oral examination. This clinical report describes management of an adult ED patient by means of telescopic overdenture prosthesis in mandibular arch and FDP in maxillary arch which restored esthetics, function, and social confidence of the patient in a cost effective manner.

Telescopic overdenture for oral rehabilitation of ectodermal dysplasia patient

PubMed Central

Gupta, Charu; Verma, Mahesh; Gupta, Rekha; Gill, Shubhra

2015-01-01

Reduced number of teeth with underdeveloped alveolar ridges poses a greatest prosthetic challenge in rehabilitation of ectodermal dysplasia patients (ED). Furthermore, surgical risks and financial constraints may preclude the implant supported prosthesis, the most desirable treatment option in an adult ED patient. Long edentulous span does not permit fixed dental prosthesis (FDP) as well. Telescopic denture by incorporating the best of both fixed and removable prosthesis can be a viable treatment alternative for ED patients with compromised dentition and limited finances. A 21-year-old young girl presented with chief complaint of esthetics and mastication due to missing upper and lower teeth. A provisional diagnosis of ED was made based on familial history, physical, and oral examination. This clinical report describes management of an adult ED patient by means of telescopic overdenture prosthesis in mandibular arch and FDP in maxillary arch which restored esthetics, function, and social confidence of the patient in a cost effective manner. PMID:26604583

Evaluation of the mineralization degree of the vestibular surface of the upper central incisors with a 655-nm diode laser in mouth breathers: preliminary results

NASA Astrophysics Data System (ADS)

Pinheiro Ladalardo, Thereza C. C. G.; Cappellette, Mario, Jr.; Zanin, Fatima A. A.; Brugnera, Aldo, Jr.; Anthero de Azevedo, Ramiro; Pignatari, Shirley; Weckx, Luc L. M.

2003-06-01

Mouth breathing unbalances the physiological mechanisms of the dental surface hydration by compromising lip closure, and, very often, causing the vestibular positioning of upper incisors. That variance leads to the interruption of the dental demineralization and remineralization feedback, prevailing a demineralized condition of the dental surface which increases caries risk. The laser fluorescence examination allows an early demineralization diagnosis, thus it makes possible through preventive measures to minimize the risk factor - dental mineral structure loss - in the bacterial infection of the demineralized area, and hence, preventing invasive therapeutical procedures. A DIAGNOdent apparatus was used to evaluate the mineralization degree of the upper central incisors in 40 patients - twenty of them with a mouth breathing diagnosis; the remaining twenty were nasal breathers (control group). Age ranging from 6 to 12 years, both male and female. To measure the vestibular surface of the incisors, it was divided into 3 segments: cervical, medial and incisal. The average of the results pertaining to the mouth breathing patients was as follows: tooth 11 cervical third - 5.45, medial third - 7.15, incisal third - 7.95, and tooth 21 - cervical third - 5.95, medial third - 7.25, incisal third - 8.15. The control patients, nasal breathers, presented the following results: tooth 11 cervical third - 1.75, medial third - 2.30, incisal third - 1.85, and tooth 21 - cervical third - 1.80, medial third - 2.20, incisal third - 2.15. The mouth breathing patients showed demineralization in the teeth examined at the initial stage, subclinical, comparing with the control patients, nasal breathers, who did not present any mineral deficit in these teeth.

Analysis of the bite force and mechanical design of the feeding mechanism of the durophagous horn shark Heterodontus francisci.

PubMed

Huber, Daniel R; Eason, Thomas G; Hueter, Robert E; Motta, Philip J

2005-09-01

Three-dimensional static equilibrium analysis of the forces generated by the jaw musculature of the horn shark Heterodontus francisci was used to theoretically estimate the maximum force distributions and loadings on its jaws and suspensorium during biting. Theoretical maximum bite force was then compared with bite forces measured (1) voluntarily in situ, (2) in restrained animals and (3) during electrical stimulation of the jaw adductor musculature of anesthetized sharks. Maximum theoretical bite force ranged from 128 N at the anteriormost cuspidate teeth to 338 N at the posteriormost molariform teeth. The hyomandibula, which connects the posterior margin of the jaws to the base of the chondrocranium, is loaded in tension during biting. Conversely, the ethmoidal articulation between the palatal region of the upper jaw and the chondrocranium is loaded in compression, even during upper jaw protrusion, because H. francisci's upper jaw does not disarticulate from the chondrocranium during prey capture. Maximum in situ bite force averaged 95 N for free-swimming H. francisci, with a maximum of 133 N. Time to maximum force averaged 322 ms and was significantly longer than time away from maximum force (212 ms). Bite force measurements from restrained individuals (187 N) were significantly greater than those from free-swimming individuals (95 N) but were equivalent to those from both theoretical (128 N) and electrically stimulated measurements (132 N). The mean mass-specific bite of H. francisci was greater than that of many other vertebrates and second highest of the cartilaginous fishes that have been studied. Measuring bite force on restrained sharks appears to be the best indicator of maximum bite force. The large bite forces and robust molariform dentition of H. francisci correspond to its consumption of hard prey.

A modified prebind engagement process reduces biomechanical loading on front row players during scrummaging: a cross-sectional study of 11 elite teams.

PubMed

Cazzola, Dario; Preatoni, Ezio; Stokes, Keith A; England, Michael E; Trewartha, Grant

2015-04-01

Biomechanical studies of the rugby union scrum have typically been conducted using instrumented scrum machines, but a large-scale biomechanical analysis of live contested scrummaging is lacking. We investigated whether the biomechanical loading experienced by professional front row players during the engagement phase of live contested rugby scrums could be reduced using a modified engagement procedure. Eleven professional teams (22 forward packs) performed repeated scrum trials for each of the three engagement techniques, outdoors, on natural turf. The engagement processes were the 2011/2012 (referee calls crouch-touch-pause-engage), 2012/2013 (referee calls crouch-touch-set) and 2013/2014 (props prebind with the opposition prior to the 'Set' command; PreBind) variants. Forces were estimated by pressure sensors on the shoulders of the front row players of one forward pack. Inertial Measurement Units were placed on an upper spine cervical landmark (C7) of the six front row players to record accelerations. Players' motion was captured by multiple video cameras from three viewing perspectives and analysed in transverse and sagittal planes of motion. The PreBind technique reduced biomechanical loading in comparison with the other engagement techniques, with engagement speed, peak forces and peak accelerations of upper spine landmarks reduced by approximately 20%. There were no significant differences between techniques in terms of body kinematics and average force during the sustained push phase. Using a scrum engagement process which involves binding with the opposition prior to the engagement reduces the stresses acting on players and therefore may represent a possible improvement for players' safety. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Effects of surface pressure and internal friction on the dynamics of shear-driven supported lipid bilayers.

PubMed

Jönsson, Peter; Höök, Fredrik

2011-02-15

Supported lipid bilayers (SLBs) are one of the most common model systems for cell membrane studies. We have previously found that when applying a bulk flow of liquid above an SLB the lipid bilayer and its constituents move in the direction of the bulk flow in a rolling type of motion, with the lower monolayer being essentially stationary. In this study, a theoretical platform is developed to model the dynamic behavior of a shear-driven SLB. In most regions of the moving SLB, the dynamics of the lipid bilayer is well explained by a balance between the hydrodynamic shear force arising from the bulk flow above the lipid bilayer and the friction between the upper and lower monolayers of the SLB. These two forces result in a drift velocity profile for the lipids in the upper monolayer of the SLB that is highest at the center of the channel and decreases to almost zero at the corners of the channel. However, near the front of an advancing SLB a very different flow behavior is observed, showing an almost constant drift velocity of the lipids over the entire bilayer front. In this region, the motion of the SLB is significantly influenced by gradients in the surface pressure as well as internal friction due to molecules that have accumulated at the front of the SLB. It is shown that even a modest surface fraction of accumulated molecules (∼1%) can drastically affect the behavior of the SLB near the bilayer front, forcing the advancing lipids in the SLB away from the center of the channel out toward the sides.

Influence of shovel-shaped incisors on the dental arch crowding in Mongolian females.

PubMed

Hasegawa, Yuh; Terada, Kazuto; Kageyama, Ikuo; Tsukada, Shin-ichi; Uzuka, Satoshi; Nakahara, Rizako; Nakahara, Sen

2009-08-01

The aim of this study was to investigate the influences of shovel-shaped incisors on the dental arch crowding in the samples of modern young female adult Mongolians (belonging to the Khalkha-Mogol grouping) ranged between 18.5 and 25.0 years, with a mean age of 20.7 years. Materials in this study comprised of 33 dental casts. Plaster replicas of the A.S.U. system plaques were used to facilitate standardization in scoring and classify shoveling regarding both upper central and lateral incisors. Dimensions of the dental arch namely, overjet, overbite, arch depth, arch width and irregularity index were measured. The correlation between the shovel shape of the central incisor and the lateral incisor was highly significant. Significantly relations were found between the grades of shoveling and the mesiodistal diameters of upper first molars and lower incisors. Positive correlation was admitted between the shoveling and upper arch depth anterior, and upper arch depth. It may be considered that the grades of shoveling are indirectly related with upper and/or lower anterior crowding. Although crowding is looks like an expression of disharmony between teeth and alveolar arch, it may be caused by multiple etiologic factors interacted directly and/or indirectly.

[Dental alveolar bone and dental arch remodeling in children: orthodontic diagnosis and treatments based on individual child arch development].

PubMed

Xiaobing, Li

2016-12-01

The etiology of malocclusions basically involves both congenital and environmental factors. Malocclusion is the result of the abnormal development of the orofacial complex (including tooth, dental alveolar bone, upper and lower jaws). Early orthodontic interceptive treatments involve the elimination of all congenital and environmental factors that contribute to the malformation of the orofacial complex, as well as interrupt the deviated development of the orofacial complex and the occlusion. Early orthodontic interceptive treatments mainly aim to use children's growth potential to correct abnormal developments of occlusions and orthodontically treat malocclusions more efficiently. The early orthodontic interceptive treatments include correcting the child's bad oral habits, training the abnormal functioned para-oral muscles, maintaining the normal eruptions of succeeding permanent teeth, applying interceptive treatments to the mal-developed teeth, and employing functional orthopedic treatments for abnormal growths of the upper and lower jaws. In orthodontics, correcting mal-positioned teeth is called orthodontic treatment, while rectifying the abnormal relationships of the upper and lower jaws is called functional orthopedic treatment. However, no clear definition is available as regards to the early orthodontic interceptive treatment of malocclusions caused by the deviated development of the dental alveolar bone. This new theory of "early dental alveolar bone and dental arch remodeling technique" was proposed by Professor Li Xiaobing of the Department of Pediatric Dentistry, Faculty of Pediatric Dentistry and Orthodontics in West China Hospital of Stomatology through his clinical analyses and investigation of his early orthodontic interceptive treatments. He defined the early orthodontic corrections of abnormal growth of dental alveolar bone as "remodel". The "early dental alveolar bone and dental arch remodeling theory and technique" is proved useful in malocclusion diagnosis and treatment planning during early orthodontic interceptive treatment with malformed dental arch. With the development of the theory and technique, the author intended to prevent and intercept the malocclusion development more effectively and efficiently. This review presents the development and clinical usages of the theory which to provide a new vision in the analysis of malocclusions on the basis of the developmental mechanism of the alveolar bone and dental arch. With clinical case illustration, the author demonstrateshis successful orthodontic clinical practices with this theory, which may contribute to the development of contemporary orthodontic theories and techniques.

Implant-supported overdenture with prefabricated bar attachment system in mandibular edentulous patient

PubMed Central

Ha, Seung-Ryong; Song, Seung-Il; Hong, Seong-Tae; Kim, Gy-Young

2012-01-01

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar® is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar® was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar® system in a mandibular edentulous patient. PMID:23236580

14 CFR Appendix I to Part 141 - Additional Aircraft Category and/or Class Rating Course

Code of Federal Regulations, 2010 CFR

2010-01-01

.... (b) For a private pilot certificate, the following aeronautical knowledge areas must be included in a... Aviation Administration for private pilot privileges, limitations, and flight operations; (2) Safe and..., including knowledge and effects of fronts, frontal characteristics, cloud formations, icing, and upper-air...

14 CFR Appendix I to Part 141 - Additional Aircraft Category and/or Class Rating Course

Code of Federal Regulations, 2011 CFR

2011-01-01

.... (b) For a private pilot certificate, the following aeronautical knowledge areas must be included in a... Aviation Administration for private pilot privileges, limitations, and flight operations; (2) Safe and..., including knowledge and effects of fronts, frontal characteristics, cloud formations, icing, and upper-air...

6. VIEW NORTH, INTERIOR OF STORE Note ceiling stripped for ...

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

6. VIEW NORTH, INTERIOR OF STORE Note ceiling stripped for addition of supports, but tongue and groove wall panelling and shelving showing. To the left the stairway enclosure was added with door for front entry to the upper apartments. - 510 Central Avenue (Commercial Building), Ridgely, Caroline County, MD

Crustal structure and tectonic deformation of the southern Ecuadorian margin

NASA Astrophysics Data System (ADS)

Calahorrano, Alcinoe; Collot, Jean-Yves; Sage, Françoise; Ranero, César R.

2010-05-01

Multichannel seismic lines acquired during the SISTEUR cruise (2000) provide new constraints on the structure and deformation of the subduction zone at the southern Ecuadorian margin, from the deformation front to the continental shelf of the Gulf of Guayaquil. The pre-stack depth migrated images allows to characterise the main structures of the downgoing and overriding plates and to map the margin stratigraphy in order to propose a chronology of the deformation, by means of integrating commercial well data and industry seismic lines located in the gulf area. The 100-km-long seismic lines show the oceanic Nazca plate underthrusting the South American plate, as well as the subduction channel and inter-plate contact from the deformation front to about 90 km landward and ~20 km depth. Based on seismic structure we identify four upper-plate units, consisting of basement and overlaying sedimentary sequences A, B and C. The sedimentary cover varies along the margin, being few hundreds of meters thick in the lower and middle slope, and ~2-3 km thick in the upper slope. Exceptionally, a ~10-km -thick basin, here named Banco Peru basin, is located on the upper slope at the southernmost part of the gulf. This basin seems to be the first evidence of the Gulf of Guayaquil opening resulting from the NE escaping of the North Andean Block. Below the continental shelf, thick sedimentary basins of ~6 to 8 km occupy most of the gulf area. Tectonic deformation across most of the upper-plate is dominated by extensional regime, locally disturbed by diapirism. Compression evidences are restricted to the deformation front and surrounding areas. Well data calibrating the seismic profiles indicate that an important portion of the total thickness of the sedimentary coverage of the overriding plate are Miocene or older. The data indicate the extensional deformation resulting from the NE motion of the North Andean Block and the opening of the Gulf of Guayaquil, evolves progressively in age from the southern edge of the gulf near Banco Peru, where main subsidence seems to be Miocene or older, toward the northern limit, where high subsidence rates are early Pleistocene.

Observing the seasonal cycle of the upper ocean in the Ross Sea, Antarctica, with autonomous profiling floats

NASA Astrophysics Data System (ADS)

Porter, D. F.; Springer, S. R.; Padman, L.; Fricker, H. A.; Bell, R. E.

2017-12-01

The upper layers of the Southern Ocean where it meets the Antarctic ice sheet undergoes a large seasonal cycle controlled by surface radiation and by freshwater fluxes, both of which are strongly influenced by sea ice. In regions where seasonal sea ice and icebergs limit use of ice-tethered profilers and conventional moorings, autonomous profiling floats can sample the upper ocean. The deployment of seven Apex floats (by sea) and six ALAMO floats (by air) provides unique upper ocean hydrographic data in the Ross Sea close to the Ross Ice Shelf front. A novel choice of mission parameters - setting parking depth deeper than the seabed - limits their drift, allowing us to deploy the floats close to the ice shelf front, while sea ice avoidance algorithms allow the floats to to sample through winter under sea ice. Hydrographic profiles show the detailed development of the seasonal mixed layer close to the Ross front, and interannual variability of the seasonal mixed layer and deeper water masses on the central Ross Sea continental shelf. After the sea ice breakup in spring, a warm and fresh surface mixed layer develops, further warming and deepening throughout the summer. The mixed layer deepens, with maximum temperatures exceeding 0ºC in mid-February. By March, the surface energy budget becomes negative and sea ice begins to form, creating a cold, saline and dense surface layer. Once these processes overcome the stable summer stratification, convection erodes the surface mixed layer, mixing some heat downwards to deeper layers. There is considerable interannual variability in the evolution and strength of the surface mixed layer: summers with shorter ice-free periods result in a cooler and shallower surface mixed layer, which accumulates less heat than the summers with longer ice-free periods. Early ice breakup occurred in all floats in 2016/17 summer, enhancing the absorbed solar flux leading to a warmer surface mixed layer. Together, these unique measurements from autonomous profilers provide insight into the hydrographic state of the Ross Sea at the start of the spring period of sea-ice breakup, and how ocean mixing and sea ice interact to initiate the summer open-water season.

Bite mark documentation and analysis: the forensic 3D/CAD supported photogrammetry approach.

PubMed

Thali, M J; Braun, M; Markwalder, Th H; Brueschweiler, W; Zollinger, U; Malik, Naseem J; Yen, K; Dirnhofer, R

2003-08-12

Bite mark identification is based on the individuality of a dentition, which is used to match a bite mark to a suspected perpetrator. This matching is based on a tooth-by-tooth and arch-to-arch comparison utilising parameters of size, shape and alignment. The most common method used to analyse bite mark are carried out in 2D space. That means that the 3D information is preserved only two dimensionally with distortions. This paper presents a new 3D documentation, analysis and visualisation approach based on forensic 3D/CAD supported photogrammetry (FPHG) and the use of a 3D surface scanner. Our photogrammetric approach and the used visualisation method is, to the best to our knowledge, the first 3D approach for bite mark analysis in an actual case. The documentation has no distortion artifacts as can be found with standard photography. All the data are documented with a metric 3D measurement, orientation and subsequent analysis in 3D space. Beside the metrical analysis between bite mark and cast, it is possible using our method to utilise the topographical 3D feature of each individual tooth. This means that the 3D features of the biting surfaces and edges of each teeth are respected which is--as shown in our case--very important especially in the front teeth which have the first contact to the skin. Based upon the 3D detailed representation of the cast with the 3D topographic characteristics of the teeth, the interaction with the 3D documented skin can be visualised and analysed on the computer screen.

Endo-Perio Lesion and Uncontrolled Diabetes.

PubMed

Dhoum, Sara; Laslami, Kaoutar; Rouggani, Fatimazahraa; El Ouazzani, Amal; Jabri, Mouna

2018-01-01

This work is to discuss the management of an endo-perio lesion, which represents a challenge to clinicians when it comes to diagnosis and prognosis of the involved teeth and especially with an altered general condition. A 50-year-old female patient with uncontrolled diabetes type 2 is suffering from a purulent discharge coming from the upper right canine. Endodontic and periodontal treatments were realized with 36 months radiological and clinical follow-up with the collaboration of her internist doctor.

Patient's Perception on the Esthetic Outcome of Anterior Fixed Prosthetic Treatment.

PubMed

Alshiddi, Ibraheem F; BinSaleh, Saad M; Alhawas, Yasser

2015-11-01

Patient's perception to the esthetic result of the treatment received can be different from a dentist opinion. Understanding patient's opinion, demand and expectation is part of successful treatment procedure. The purpose of this study was to investigate patient's opinion about the esthetic result of the fixed prosthetic treatment received in upper anterior teeth. About 90 volunteer subjects, 58 males and 32 females were given a self-evaluation questionnaire with 11 questions to respond as Yes or No. The questions regarded the esthetic result of a fixed prosthodontic treatment received for their upper anterior teeth. The same questioner was completed for each subject by three clinicians through clinical photographs for different views of subject's smile. Agreement between patients and clinicians was calculated for all subjects to evaluate patient's perception to their esthetic results. An agreement of 47.8 to 72.2% was observed between patients and clinicians, and the average agreement was 53.64 to 60%. The highest agreement was related to satisfaction with the color of the crown and/or bridge margin while the least agreement was related to the satisfaction with the natural looking of the restoration. There was variability in the agreement between the patients and the dentists with the satisfaction of the esthetic result of anterior restoration. Factor, such as gender, age and educational level may affect the results of the agreement.

Comparison of diameters at the cementoenamel junction between South Asians and Japanese.

PubMed

Nose, Hirohisa; Tawada, Yasuyuki; Watanabe, Fumihiko; Kageyama, Ikuo

2011-01-01

Previously, sex differences among the various tooth types in Japanese skulls were examined to facilitate choosing an implant diameter similar to the cervical diameter of each tooth, and it was found that mesiodistal diameters at the cementoenamel junction were narrower in women than in men. Also interesting and relevant to the selection of implant diameter is the possible existence of racial differences in diameters at the cementoenamel junction. The purpose of this research was to test the hypothesis that the diameter at the cementoenamel junction of the tooth differs in humans of different races. We compared 106 skulls of unknown sex collected from South Asia with the skulls of Japanese women. Our conclusions are as follows: (1) Except for the lower canine, no significant racial differences were found in the labiolingual diameter of any teeth. (2) Except for the upper canine, upper central incisor, lower second premolar, and lower first premolar, a significant racial difference was found in the mesiodistal diameter. In all teeth in which this value differed, the mesiodistal diameters of South Asians were narrower than those of Japanese women, except for the lower canine. (3) The labiolingual and mesiodistal diameters of the lower canine were significantly larger in South Asians than in Japanese women. (4) Among South Asians, no significant left/right differences were found in the diameter at the cementoenamel junction of any tooth.

The functional and palaeoecological implications of tooth morphology and wear for the megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada.

PubMed

Mallon, Jordan C; Anderson, Jason S

2014-01-01

Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian) of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis of dietary niche partitioning. The inferred mechanical and dietary patterns appear constant over the 1.5 Myr timespan of the Dinosaur Park Formation megaherbivore chronofauna, despite continual species turnover.

The Functional and Palaeoecological Implications of Tooth Morphology and Wear for the Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada

PubMed Central

Mallon, Jordan C.; Anderson, Jason S.

2014-01-01

Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian) of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis of dietary niche partitioning. The inferred mechanical and dietary patterns appear constant over the 1.5 Myr timespan of the Dinosaur Park Formation megaherbivore chronofauna, despite continual species turnover. PMID:24918431

The maxillary second molar - anatomical variations (case report).

PubMed

Beshkenadze, E; Chipashvili, N

2015-01-01

To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the individuality of treatment tactics.

Self-perception and satisfaction with dental appearance and aesthetics with respect to patients’ age, gender, and level of education.

PubMed

Strajnić, Ljiljana; Bulatović, Dijana; Stančić, Ivica; Živković, Rade

2016-01-01

Patient’s subjective evaluation of dental appearance and aesthetics is becoming an increasingly important factor in aesthetic treatments and prosthetic therapy. The aim of this study was to investigate the influence of age, education level, gender, and different dental status and the appearance of the upper anterior teeth (color, size, shape, position and alignment of the anterior teeth) on the satisfaction of the respondents with dental appearance and aesthetics of their upper anterior teeth and their desire for improvement. The study encompassed 480 people aged 20 to 50 years with an average age of 30.84 years. There were 236 male and 244 female subjects. The respondents were interviewed using a questionnaire specially designed for the purpose of this research. For the study, the subjects were divided into the following three age groups: the younger age group (20–30 years of age), the middle age group (31–40 years of age), and the older age group (41–50 years of age). The conducted study did not reveal statistical significance with respect to gender in any of the examined parameters (p > 0.05). A little more than one half of the respondents in each age group were satisfied with their dental appearance and aesthetics (60.3% of the respondents in the age group of 20–30 years, 55.7% in the age group of 31–40, and 53.7% in the age group of 41–50 years of age). Satisfaction with dental appearance and aesthetics increases linearly with the increase in the level of education and was the highest among the respondents with university degree (33.3%). Female respondents were more dissatisfied with their dental appearance and aesthetics as compared with male respondents, but the difference was found to be non-significant. Patients with higher education level were more satisfied with their dental appearance and aesthetics than those with lower education.

Analysis of a general circulation model product. I - Frontal systems in the Brazil/Malvinas and Kuroshio/Oyashio regions

NASA Technical Reports Server (NTRS)

Garzoli, Silvia L.; Garraffo, Zulema; Podesta, Guillermo; Brown, Otis

1992-01-01

The general circulation model (GCM) of Semtner and Chervin (1992) is tested by comparing the fields produced by this model with available observations in two western boundary current regions, the Brazil/Malvinas and the Kuroshio/Oyashio confluences. The two sets of data used are the sea surface temperature from satellite observations and the temperature field product from the GCM at levels 1 (12.5 m), 2 (37.5 m), and 6 (160 m). It is shown that the model reproduces intense thermal fronts at the sea surface and in the upper layers (where they are induced by the internal dynamics of the model). The location of the fronts are reproduced in the model within 4 to 5 deg, compared with observations. However, the variability of these fronts was found to be less pronounced in the model than in the observations.

Application of interleaving models for the description of intrusive layering at the fronts of deep polar water in the Eurasian Basin (Arctic)

NASA Astrophysics Data System (ADS)

Kuzmina, N. P.; Zhurbas, N. V.; Emelianov, M. V.; Pyzhevich, M. L.

2014-09-01

Interleaving models of pure thermohaline and baroclinic frontal zones are applied to describe intrusions at the fronts found in the upper part of the Deep Polar Water (DPW) when the stratification was absolutely stable. It is assumed that differential mixing is the main mechanism of the intrusion formation. Important parameters of the interleaving such as the growth rate, vertical scale, and slope of the most unstable modes relative to the horizontal plane are calculated. It was found that the interleaving model for a pure thermohaline front satisfactory describes the important intrusion parameters observed at the frontal zone. In the case of a baroclinic front, satisfactory agreement over all the interleaving parameters is observed between the model calculations and observations provided that the vertical momentum diffusivity significantly exceeds the corresponding coefficient of mass diffusivity. Under specific (reasonable) constraints of the vertical momentum diffusivity, the most unstable mode has a vertical scale approximately two-three times smaller than the vertical scale of the observed intrusions. A thorough discussion of the results is presented.

Cemental tear: To know what we have neglected in dental practice.

PubMed

Jeng, Po-Yuan; Luzi, Arlinda Luzi; Pitarch, Rocio Marco; Chang, Mei-Chi; Wu, Yu-Hsueh; Jeng, Jiiang-Huei

2018-04-01

Cemental tear is a special kind of root surface fracture, contributing to periodontal and periapical breakdown. However, it is a challenge for doctors to diagnose, resulting in delayed or improper treatment. We reviewed the predisposing factors, location, radiographic/clinical characteristics, diagnosis and treatments of cemental tears. From the literature, patients with cemental tear were mainly males, over 60 year-old. Possible predisposing factors include gender, age, tooth type, traumatic occlusal force and vital teeth. Cemental tears were common in upper and lower anterior teeth, single or multiple, and can be present in cervical, middle and apical third of roots. Morphology of cemental tears can be either piece-shaped or U-shaped. Clinically, cemental tear shows a unitary periodontal pocket and signs/symptoms mimicking localized periodontitis, apical periodontitis and vertical root fractures. Treatment of cemental tears include scaling, root planning, root canal treatment, periodontal/periapical surgery, guided tissue regeneration, bone grafting, and intentional replantation. Recurrence of cemental tear is possible especially when the fracture involves root apex. Extraction is recommended for teeth with poor prognosis. In conclusion, cemental tears can involve both periodontal and periapical area. Dentists should understand the predisposing factors and clinical features of cemental tears for early diagnosis/treatment to prevent bone loss/tooth extraction. Copyright © 2017. Published by Elsevier B.V.

Oral Health Status of Older Adults Attending Senior Centers and Congregate Meal Sites in New Hampshire.

PubMed

Anderson, Ludmila; Martin, Nancy R; Kelly, Stephanie M; Brown, Heather A

2016-04-01

This study assessed the oral health status of older adults in randomly selected New Hampshire senior centers and congregate meal sites for the purpose of future planning, implementation and evaluation of targeted public health programs. A cross-sectional surveillance project was developed. Registered dental hygienists visually assessed denture use, number of natural teeth, teeth mobility, untreated caries, root fragments, gingivitis, need for care and treatment urgency among randomly selected active older adults living within New Hampshire communities. Altogether, 610 adults 60 years old and older attending 25 senior centers and congregate meal sites participated. Sixteen percent were edentulous and 42% reported having a removable upper or lower denture. Among edentulous adults, 5% had no dentures at all. Among 513 dentate participants, 22% had untreated caries, 14% had root fragments, 9% had gingivitis and 7% presented with obviously mobile teeth. Overall, 19% required early or urgent dental care. Differences were detected by sex, age group, urban versus rural location of the site and by the participation in a federal nutritional program for older adults. Baseline information about oral health needs of older adults in New Hampshire was gathered. Overall needs as well as existing oral health disparities will be addressed through the collaboration of public and private partners. Copyright © 2016 The American Dental Hygienists’ Association.

Autotransplantation of immature third molars using a computer-aided rapid prototyping model: a report of 4 cases.

PubMed

Jang, Ji-Hyun; Lee, Seung-Jong; Kim, Euiseong

2013-11-01

Autotransplantation of immature teeth can be an option for premature tooth loss in young patients as an alternative to immediately replacing teeth with fixed or implant-supported prostheses. The present case series reports 4 successful autotransplantation cases using computer-aided rapid prototyping (CARP) models with immature third molars. The compromised upper and lower molars (n = 4) of patients aged 15-21 years old were transplanted with third molars using CARP models. Postoperatively, the pulp vitality and the development of the roots were examined clinically and radiographically. The patient follow-up period was 2-7.5 years after surgery. The long-term follow-up showed that all of the transplants were asymptomatic and functional. Radiographic examination indicated that the apices developed continuously and the root length and thickness increased. The final follow-up examination revealed that all of the transplants kept the vitality, and the apices were fully developed with normal periodontal ligaments and trabecular bony patterns. Based on long-term follow-up observations, our 4 cases of autotransplantation of immature teeth using CARP models resulted in favorable prognoses. The CARP model assisted in minimizing the extraoral time and the possible Hertwig epithelial root sheath injury of the transplanted tooth. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Traumatic dental injuries and related factors among sixth grade schoolchildren in four Palestinian towns.

PubMed

Livny, Alon; Sgan-Cohen, Harold D; Junadi, Samer; Marcenes, Wagner

2010-10-01

Traumatic dental injuries (TDI) are recognized as an important dental public health issue among children. The West Bank, a part of the Palestinian Authority, is in immediate neighborhood to Israel. There are inadequate epidemiologic data among the Palestinian people, on dental health issues. To determine the occurrence of TDI to permanent teeth among sixth grade Palestinian schoolchildren living in four large towns of the West Bank and to investigate associations with anatomic and demographic factors. Eight hundred and four children were sampled and examined in Ramallah, Bethlehem, Hebron and Jericho. Data collection included clinical examinations in schools and questionnaires for demographic and socio-economic background. The prevalence of traumatic dental injuries was 17.7%. Enamel fractures and injuries involving dentine accounted for 41% and 42.5% of all injuries, respectively. The most affected teeth (89%) were upper central incisors. Only 5% of the injured teeth were treated. Results of multiple logistic regression confirmed that TDI were significantly (P < 0.001) more prevalent among boys, children presenting incisal overjet larger than 5 mm, and incompetent lip coverage. The relative high prevalence and very low levels of treated TDI identified in this study suggested that both prevention and treatment of TDI in the West Bank were inadequate. © 2010 John Wiley & Sons A/S.

Impact of diet on incisor growth and attrition and the development of dental disease in pet rabbits.

PubMed

Meredith, A L; Prebble, J L; Shaw, D J

2015-06-01

To assess the impact of four rabbit diets (hay only; extruded diet with hay; muesli with hay; muesli only) on length and curvature of cheek teeth and eruption and attrition rates of incisors. Thirty-two Dutch rabbits, randomly divided into four diet groups, had length and saggital plane curvature of the first cheek teeth measured radiographically at 1, 9 and 17 months. Eruption/attrition of the left upper incisor was directly measured at weeks 30, 32 and 35. Eruption rates matched attrition rates in all groups, but were higher in the hay only group than in both groups fed muesli. By month 9, a greater degree of tooth curvature was present in rabbits fed muesli only than in those fed hay only and extruded diet with hay. After 17 months, rabbits fed muesli only and muesli with hay had longer lower first cheek teeth and larger interdental spaces between the first two molars than rabbits fed extruded diet and hay and hay only. Three rabbits fed muesli only developed evidence of dental disease. Presence of increased tooth length, curvature and interdental spaces indicated early dental pathology in rabbits fed muesli. Muesli diets cannot be recommended for pet rabbits. © 2015 British Small Animal Veterinary Association.

An investigation of the heat induced during ultrasonic post removal.

PubMed

Ettrich, Christopher A; Labossière, Paul E; Pitts, David L; Johnson, James D

2007-10-01

The purpose of this study was to investigate the potential for temperature increase along the external root surface during ultrasonic post removal in a simulated clinical environment. Thirty-seven extracted teeth were decoronated, instrumented, and then obturated with gutta-percha and sealer. Post spaces were prepared, followed by cementation of stainless steel posts. A simulated clinical environment was created by using a polymethylmethacrylate sheet with holes custom fitted for the extracted teeth and then suspended over a heated water bath. Two thermocouples were attached at 6 and 12 mm from the top of the post along the external root surface. Teeth were divided into 3 test groups, no coolant, air-cooled, and water-cooled. Temperature changes were recorded by using a Vishay 5000 Strain Smart system. Results demonstrated that a significant difference existed in the average heat rates between the upper and lower thermocouples for no coolant and water-cooled groups at the medium setting and the air-cooled group at the high setting. The average heat rates were significantly different between the 2 thermocouples for all 3 groups when comparing the 2 ultrasonic power settings. Results indicated that the average heat rate was less for the water-cooled group when using a medium power setting.

Dental size and shape in the Roman imperial age: two examples from the area of Rome.

PubMed

Manzi, G; Santandrea, E; Passarello, P

1997-04-01

Different socioeconomic strata of Roman imperial age are represented by two large dental samples recovered from archaeological excavations near Rome, Italy. Teeth are investigated for crown dimensions and morphological variants. One sample, comprising 1,465 permanent teeth, represents the rural town of Lucus Feroniae (LFR) and is mainly composed of slaves and war veterans. The other, comprising 734 teeth from the Isola Sacra necropolis at Portus Romae (NIS), represents the "middle class" segment of an urban population. Both series show small dental dimensions and fit at the lower end of the trend toward dental reduction in Europe from the Upper Paleolithic to the historical times. The urban sample is less variable metrically and less sexually dimorphic than the rural one. The analysis of discrete crown traits shows absence of rare phenotypic variants in both series. The urban sample is also less variable in this last respect, suggesting that the gene pool of this particular "stratum" of the NIS population was more homogeneous than that of LFR. The occurrence of enamel hypoplasia indicates that metabolic stress during growth and development was similar in LFR and NIS. The overall set of available data is evaluated in the light of the history of the two Roman sites and the composition of each population.

Gear distortion analysis due to heat treatment process

NASA Astrophysics Data System (ADS)

Guterres, Natalino F. D. S.; Rusnaldy, Widodo, Achmad

2017-01-01

One way to extend the life time of the gear is minimizing the distortion during the manufacturing process. One of the most important processes in manufacturing to produce gears is heat treatment process. The purpose of this study is to analyze the distortion of the gear after heat treatment process. The material of gear is AISI 1045, and it was designed with the module (m) 1.75, and a number of teeth (z) 29. Gear was heat-treated in the furnace at a temperature of 800°C, holding time of 30 minutes, and then quenched in water. Furthermore, surface hardening process was also performed on gear teeth at a temperature of 820°C and holding time of 35 seconds and the similar procedure of analysis was conducted. The hardness of gear after heat treatment average 63.2 HRC and the teeth surface hardness after gear to induction hardening was 64.9 HRC at the case depth 1 mm. The microstructure of tested gear are martensitic and pearlite. The highest distortion on tooth thickness to upper than 0.063 can cause high precision at the tooth contact is not appropriate. Besides the shrinkage of tooth thickness will also affect to contact angle because the size of gear tolerance was not standardized.

Guided Endodontics: a novel treatment approach for teeth with pulp canal calcification and apical pathology.

PubMed

Krastl, Gabriel; Zehnder, Marc S; Connert, Thomas; Weiger, Roland; Kühl, Sebastian

2016-06-01

To present a new treatment approach for teeth with pulp canal calcification (PCC) which require root canal treatment. A 15-year-old male patient presented with pain of his upper right central incisor. The tooth showed signs of apical periodontitis. Due to PCC, location of the root canal was judged to be difficult and associated with a high risk of perforation. A cone beam computed tomography (CBCT) and an intra-oral surface scan were performed and matched using software for virtual implant planning. After planning the position of the drill for root canal location, a virtual template was designed, and the data were exported as an STL file and sent to a 3D printer for template fabrication. The template was positioned on the anterior maxillary teeth. A specific drill was used to penetrate through the obliterated part of the root canal and obtain minimally invasive access to the apical part. The root canal was accessible at 9 mm distance from the apex. Further root canal preparation was carried out using an endodontic rotary instrumentation system. After an interappointment dressing for 4 weeks, the root canal was filled with vertically condensed gutta-percha using an epoxy sealer. The access cavity was restored with a composite material. After 15 months, the patient was clinically asymptomatic with no pain on percussion. The radiograph showed no apical pathology. The presented guided endodontic approach seems to be a safe, clinically feasible method to locate root canals and prevent root perforation in teeth with PCC. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[All-ceramic resin bonded fixed partial denture made of IPS hot-pressed casting porcelain restore anterior missing teeth: a three years clinical observation].

PubMed

Zhou, Tuan feng; Wang, Xin zhi; Zhang, Gui rong

2011-02-18

To clinic observation of IPS Empress2 and IPS e.max all ceramic resin bonded fixed partial dentures used in one anterior teeth lost in upper jaw or less than two anterior tooth lost in lower jaw. 22 patients, 26 restorations had been made, which included 16 single-retainer all ceramic resin bonded fixed partial dentures and 10 two-retainers all ceramic resin bonded fixed partial dentures. Secondary caries of the abutments, shade in the margin of the retainers and the integrity of the restorations had been observed at 3 months, 6 months, 1 year, 2 years and 3 years after all ceramic resin bonded fixed partial dentures having been bonded. In the 3 years of clinic observation of the anterior all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond after it had been made for 3 months, a retainer of one two-retainers restoration was broken after 6 months, but they are still used after modified as one-retainer all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond two year later, It was integrity and re-bonded again that was still stable. No secondary carries and no shade in margin of the retainers had been found. Their color matches with the nature teeth excellently. The success rate was 88.5%. IPS Empress 2 and IPS e.max all ceramic resin bonded fixed partial dentures should be a good selection in one or two teeth lose in anterior jaws.

Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates.

PubMed

Smith, Timothy D; Muchlinski, Magdalena N; Jankord, Kathryn D; Progar, Abbigal J; Bonar, Christopher J; Evans, Sian; Williams, Lawrence; Vinyard, Christopher J; Deleon, Valerie B

2015-12-01

In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate. © 2015 Wiley Periodicals, Inc.

Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates

PubMed Central

Smith, Timothy D.; Muchlinksi, Magdalena N.; Jankord, Kathryn D.; Progar, Abbigal J.; Bonar, Christopher J.; Evans, Sian; Williams, Lawrence; Vinyard, Christopher J.; DeLeon, Valerie B.

2015-01-01

In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate. PMID:26425925

A secondary nursery area for the copper shark Carcharhinus brachyurus from the late Miocene of Peru

NASA Astrophysics Data System (ADS)

Landini, Walter; Collareta, Alberto; Pesci, Fabio; Di Celma, Claudio; Urbina, Mario; Bianucci, Giovanni

2017-10-01

The life history strategies of sharks often include the use of protected nursery areas by young-of-the-year and juveniles. Nursery areas can be primary (i.e., grounds where the sharks are born and spend the very first part of their lives) or secondary (i.e., grounds inhabited by slightly older but not yet mature individuals). Criteria utilized to recognize these strategic habitats include: high concentration of young sharks, high food availability, and low predation risk. Since the fossil record of sharks consists mainly of isolated teeth, identification of paleonurseries involves a series of problems due to difficult application of actualistic criteria. A rich shark tooth-bearing level (ST-low1) has recently been discovered in the upper Miocene deposits of the Pisco Formation exposed at Cerro Colorado (southern coast of Peru). Most of the teeth collected from this level belong to the extant copper shark Carcharhinus brachyurus. These teeth are small and compatible with those of extant juveniles. This observation, coupled with other paleoenvironmental considerations, indicates that the ST-low1 horizon could have represented a nursery ground for juvenile individuals of C. brachyurus. The absence of very small-sized teeth (i.e., referable to young-of-the-year) suggests a secondary nursery ground inhabited by immature copper sharks. Observations on the tooth size of other Lamniformes, Carcharhiniformes, and Myliobatiformes occurring along with C. brachyurus point to a significantly juvenile structure of this elasmobranch assemblage, thus supporting the hypothesis of a communal use of the Cerro Colorado paleonursery.

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

PubMed

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

2009-01-01

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

Autonomous Observations of the Upper Ocean Stratification and Velocity Fields About the Seasonally-Retreating Marginal Ice Zone

DTIC Science & Technology

2015-09-30

ITP data is underway on multiple fronts. A few scientific highlights follow: An undergraduate student from VIT University in India, Ratnaksha...Yale University PO Box 208109 New Haven, CT 06520-8109 phone: (203) 432-3167 fax: (203) 432 3134 email: mary-louise.timmermans@yale.edu

Pattern of dental development in Hominid XVIII from the Middle Pleistocene Atapuerca-Sima de los Huesos site (Spain).

PubMed

Bermudez De Castro, J M; Rosas, A

2001-04-01

. We describe the pattern of dental development of Hominid XVIII from the Middle Pleistocene Sima de los Huesos (SH) site of the Sierra de Atapuerca (Burgos, Spain). As expected, this pattern is similar to that of modern humans. A delay of development of the lower and upper canines was observed. In contrast, the relative advanced development of the lower second molars and, especially, the upper and lower third molars is noteworthy. This latter feature seems to be common in Pleistocene hominids, and suggests that the pattern of dental development evolved in the genus Homo during the Pleistocene. In European Middle Pleistocene hominids, this pattern probably was facilitated by the extra space available in the mandible and maxilla for developing teeth. Copyright 2001 Wiley-Liss, Inc.

Endo-Perio Lesion and Uncontrolled Diabetes

PubMed Central

Laslami, Kaoutar; Rouggani, Fatimazahraa; El Ouazzani, Amal; Jabri, Mouna

2018-01-01

This work is to discuss the management of an endo-perio lesion, which represents a challenge to clinicians when it comes to diagnosis and prognosis of the involved teeth and especially with an altered general condition. A 50-year-old female patient with uncontrolled diabetes type 2 is suffering from a purulent discharge coming from the upper right canine. Endodontic and periodontal treatments were realized with 36 months radiological and clinical follow-up with the collaboration of her internist doctor. PMID:29888011

Subdural abscess secondary to covert dental sepsis

PubMed Central

Sprott, Mae S.; Hall, K.; Newman, P. K.; Welbury, R. R.; Ingham, H. R.

1981-01-01

The bacterial flora of a subdural abscess in a 17-year-old male, with radiological evidence of unilateral infection of the maxillary and frontal air sinuses, was typical of that encountered in the dental sulcus. Extensive examination revealed no primary focus of infection other than apical infection in the 2 upper first molar teeth, which were extracted. Treatment with ampicillin, gentamicin and metronidazole rapidly controlled the subdural infection, and resolution, as evidenced by computerized tomography, was complete at 10 months. PMID:7335566

[Plastic bonding material as the origin of mucosal disorders].

PubMed

Kühl, W

1979-10-01

A case reported in which the patient complained of sensations in the musoca over a period of one year. Various other specialists were consulted, but the cause of these sensations could not be established. When the plastic facing on the upper anterior crowns was removed, the sensations disappeared. A metal-ceramic bridge was inserted, and the patient was fitted with a removable dental prosthesis containing teeth made of mineral substance and a base of injection moulding (Copodon). The patient is still free of complaints.

Frontogenesis and turbulent mixing

NASA Astrophysics Data System (ADS)

Zhang, S.; Chen, F.; Shang, Q.

2017-12-01

A hydrological investigation was conducted in the shelf of eastern Hainan island during July 2012. With the in-situ measurements from four cross-shelf sections and satellite data, the submesoscale process of the fronts are discussed in this paper, the seasonal variation characteristics of thermal front, the three-dimensional structure, dynamic characteristics of frontal and mixed characteristics in the shelf sea of eastern Hainan island. It's obviously that the thermal front has a seasonal variation: the front is strongest in winter, and decreased gradually in spring and summer. However, it fade and disappear in fall. The core region of the front also changes with the seasons, it moved southward gradually from mainly distributed in the upwelling zone and the front center is not obvious in summer. it is a typical upwelling front in summer, the near shore is compensated with the underlying low-temperature and high-sale water , while the offshore is the high-temperature and low-salinity shelf water. The thermal front distribution is located in the 100m isobaths. The frontal intensity is reduced with increasing depth, and position goes to offshore. Subsurface temperature front is significantly higher in the surface of the sea, which may cause by the heating of nearshore sea surface water and lead to the weakening horizontal temperature gradient. Dynamic characteristics of the front has a great difference in both sides. The O(1) Rossby number is positive on the dense side and negative on the light side. The maximum of along-frontal velocity is 0.45m/s and the stretching is strengthened by strong horizontal shear, also is the potential vorticity, which can trace the cross front Ekman transport. We obtained the vertical velocity with by quasi-geostrophic omega equation and grasped the ageostrophic secondary circulation. The magnitude of frontal vertical velocity is O(10-5) and causes downwelling on the dense side and upwelling on the light side, which constitute the ageostrophic secondary circulation together with the cross-frontal ageostrophic speed. The mixed characteristic is weak in summer, but the large turbulent dissipation and mixing rate measured in the frontal region, which show that the front promoted exchange of material and energy in the upper ocean.

Soccer players' fitting perception of different upper boot materials.

PubMed

Olaso Melis, J C; Priego Quesada, J I; Lucas-Cuevas, A G; González García, J C; Puigcerver Palau, S

2016-07-01

The present study assessed the influence of upper boot materials on fitting perception. Twenty players tested three soccer boots only differing in the upper boot material (natural calf leather, natural kangaroo leather and synthetic leather). Players reported fitting perception and preference on specific foot areas using a perceived fitting scale. Ratings were averaged for every foot area. Repeated measures ANOVA was used to analyze the differences between boots. The kangaroo leather boots were perceived tighter and closer to the preferred fitting in general fitting, metatarsals area and instep area. The synthetic leather boots were perceived as the loosest and as the most distant boot from the preferred fitting in medial front area and instep area. In conclusion, the type of upper boot material influences the fitting perception of soccer players. The kangaroo leather was the material whose fitting was perceived closest to the players fitting preference. Copyright © 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved.

A climatology based on reanalysis of baroclinic developmental regions in the extratropical northern hemisphere.

PubMed

de la Torre, Laura; Nieto, Raquel; Noguerol, Marta; Añel, Juan Antonio; Gimeno, Luis

2008-12-01

Regions of the occurrence of different phenomena related to the development of baroclinic disturbances are reviewed for the Northern Hemisphere extratropics, using National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. The occurrence of height lows appears to be related to the orography near the earth's surface and with surface- and upper-air cyclogenesis in the upper troposphere. Over the cyclone tracks, the surface maxima appear to be trapped by land masses, whereas over the Mediterranean Sea they are located on the lee side of mountain ranges. The forcing terms of the geopotential tendency and omega equations mark the genesis (and, by the vorticity advection terms, the path) of the extratropical cyclones on the storm track. They occur mostly over the western coast of the oceans, beginning and having maxima on the lee side of the Rocky Mountains and the Tibetan Plateau. Their associated fronts form from the cold air coming from the continents and converging with the warm air over the Gulf and Kuroshio currents. Evident trends are found only for the Atlantic cyclone track (positive) and the Pacific cyclone track (negative) until the last decade when the tendency reverses. Over the southern Pacific, the number of fronts is lower during 1978-1997, coinciding with a period of strong El Niño Southern Oscillation episodes. This information is important for validating numerical models in order to predict changes associated with climate change and to study the behavior of extratropical cyclones and fronts.

A Gulf Stream-derived pycnocline intrusion on the Middle Atlantic Bight shelf

NASA Astrophysics Data System (ADS)

Gawarkiewicz, Glen; McCarthy, Robert K.; Barton, Kenneth; Masse, Ann K.; Church, Thomas M.

1990-12-01

Saline intrusions from the upper slope onto the outer shelf are frequently observed at the pycnocline along the shelfbreak front in the Middle Atlantic Bight during the summer. A brief cruise was conducted in July, 1986 between Baltimore and Washington Canyons to examine along-shelf variability of pycnocline salinity intrusions. A particularly saline intrusion of 35.8 Practical Salinity Units (PSU) was observed between 20 and 40 m in a water depth of 70 to 80 m. The along-shelf extent was at least 40 km. The cooler, sub-pycnocline outer shelf water was displaced 15 km shoreward of the shelfbreak. A Gulf Stream filament was present in the slope region prior to the hydrographic sampling, but was not visible in thermal imagery during the hydrographic sampling. Temperature-salinity characteristics of the intrusion suggest that it was a mixture of Gulf Stream water and slope water, possibly from the filament. The shoreward penetration of saline water was most pronounced at the pycnocline and penetrated the shelfbreak front, with salinities as high as 35.0 PSU reaching as far shoreward as the 35 m isobath. These pycnocline intrusions may be an important mechanism for the transport of Gulf Stream-derived water onto the shelf during the summer. The presence of filaments or other Gulf Stream-derived water on the upper slope may account for some of the along-front variability of the pycnocline salinity maximum that has previously been observed.

Oblique Loading in Post Mortem Human Surrogates from Vehicle Lateral Impact Tests using Chestbands.

PubMed

Yoganandan, Narayan; Humm, John R; Pintar, Frank A; Arun, Mike W J; Rhule, Heather; Rudd, Rodney; Craig, Matthew

2015-11-01

While numerous studies have been conducted to determine side impact responses of Post Mortem Human Surrogates (PMHS) using sled and other equipment, experiments using the biological surrogate in modern full-scale vehicles are not available. The present study investigated the presence of oblique loading in moving deformable barrier and pole tests. Threepoint belt restrained PMHS were positioned in the left front and left rear seats in the former and left front seat in the latter condition and tested according to consumer testing protocols. Three chestbands were used in each specimen (upper, middle and lower thorax). Accelerometers were secured to the skull, shoulder, upper, middle and lower thoracic vertebrae, sternum, and sacrum. Chestband signals were processed to determine magnitudes and angulations of peak deflections. The magnitude and timing of various signal peaks are given. Vehicle accelerations, door velocities, and seat belt loads are also given. Analysis of deformation contours, peak deflections, and angulations indicated that the left rear seated specimen were exposed to anterior oblique loading while left front specimens in both tests sustained essentially pure lateral loading to the torso. These data can be used to validate human body computational models. The occurrence of oblique loading in full-scale testing, hitherto unrecognized, may serve to stimulate the exploration of its role in injuries to the thorax and lower extremities in modern vehicles. It may be important to continue research in this area because injury metrics have a lower threshold for angled loading.

[Three-dimensional analysis of the early correction of anterior crossbite using eruption guidance appliance].

PubMed

Wang, X; Zhang, J J; Yuan, F S; Wang, Y; Li, C H; Varrela, J E; Yue, J; Ge, L H

2018-06-18

To investigate the clinical effect of eruption guidance appliance in the treatment of anterior cross bite in mixed-dentition children. In the study,10 mixed-dentition children with anterior cross bite, totally 12 incisors, were selected. Alginate was used to take upper and lower dentition impression and make a hard plaster model,which served as the eruption guidance appliance for treatment. The pre- and post-operative dental casts were digitized with SmartOptics Activity 880 scanner,and the three-dimensional overlapping models were obtained by reverse engineering software,Geomagic Studio 2012,then the three-dimensional movements of the upper and lower incisors were analyzed using Imageware 13.2 software. The overbite and overjet were analyzed using the same methods. Measurement with copper wire was used to analyze the upper and lower arch length. Space analysis was the result by the sum of crown width minus the arch length. The crown width of unerupted permanent teeth was according to X-ray method to predict. The SPSS 17.0 software was used to analyze the pre- and post-operative measurements of the same child. The normality test of the measured data showed that it conformed to the normal distribution. Therefore,the t test and double side test were used,and the significance level was 0.05. The course of treatment was (5.6±2.7) months. During orthodontic treatment, the upper incisors moved mainly labially (P<0.001) in three-dimensional displacement, and the lower incisors moved mainly the same direction (P=0.025). During the treatment of eruption guidance appliance,the average overbite decreased (1.01±0.9) mm (t=-3.531, P=0.006), and the difference was statistically significant. There was no statistically significant difference between the pre- and post-operative average overjet (t=0.771, P=0.460). The severity of crowding in upper arch decreased (1.9±0.99) mm (t=-6.042, P<0.001),and that in lower arch decreased (1.9±0.74) mm (t=-8.143, P<0.001), both of the differences were statistically significant. The anterior cross bite in mixed dentition could be corrected by eruption guidance appliance, and at the same time, the normal overjet and overbite were established, and the teeth were aligned.

Maxillary tridimensional changes after slow expansion with leaf expander in a sample of growing patients: a pilot study.

PubMed

Lanteri, V; Gianolio, A; Gualandi, G; Beretta, M

2018-03-01

The aim of this study is to evaluate the dento-alveolar effects of slow maxillary expansion using the Leaf Expander in a sample of growing patients with maxillary transverse deficiency, unilateral cross bite and mandibular shift. The study included 10 patients, 3 male and 7 female (mean age 7.5 + 7 months), treated with Leaf Expander anchored on the upper deciduous teeth. Digital models were obtained by a lab scan of the pvs impressions at the beginning of the therapy (T1) and at the removal of the palatal expander (T2). Five parameters were measured: 1) the distance between the first upper permanent molars; 2) the distance between the upper second deciduous molars; 3) the distance between the upper canine cusps 4) the distance between the first lower permanent molars; 5) the distance of the lower canine cusps. In all patients complete correction of posterior crossbite was achieved on average in 4 months, with a spontaneous expansion of the upper first permanent molars. Significant increases in the dento-alveolar transversal diameters were obtained. Increases were also observed in the anterior mandibular arch diameter (+ 1 mm). These findings suggest that slow maxillary expansion using Leaf Expander appliance could be a reasonable alternative to conventional maxillary expansion therapy in the early mixed dentition.

The Andean orogenic front at Sierra de Las Peñas-Las Higueras, Mendoza, Argentina

NASA Astrophysics Data System (ADS)

Costa, Carlos H.; Gardini, Carlos E.; Diederix, Hans; Cortés, José M.

2000-07-01

The Sierra de Las Peñas-Las Higueras (Mendoza Province, Argentina, 32°15'S-32°45'S) presents one of the clearest and most continuous exposures of the Quaternary thrust front of the Precordilleran fold-and-thrust belt. It is characterized by an east-verging thrust that breaks the surface and causes Neogene sedimentary rocks to override Quaternary alluvial conglomerates. Monoclinal folds and progressive unconformities are characteristic of deformation in the upper part of the alluvial cover, indicating synchronous development of sedimentation and thrusting during the Quaternary. South of this range, ongoing deformation is by gentle warping of the piedmont alluvial plain, hiding blind thrusts at depth.

Dental erosion and severe tooth decay related to soft drinks: a case report and literature review.

PubMed

Cheng, Ran; Yang, Hui; Shao, Mei-ying; Hu, Tao; Zhou, Xue-dong

2009-05-01

Soft drinks have many potential health problems. The inherent acids and sugars have both acidogenic and cariogenic potential, resulting in dental caries and potential enamel erosion. In this report we present a 25-year-old man complaining with the severe worn-out of the front teeth during the past 3 years. He had a history of drinking cola for more than 7 years and had a poor oral hygiene. Severe decays were present in the incisors and the canines, while less severe lesions were noted on the premolars and the molars. The review is to show the relationship between dental erosion and caries and soft drinks. Some efforts have been taken to reduce the harmful effect of soft drinks.

Mental foramen and lingual vascular canals of mandible on MDCT images: anatomical study and review of the literature.

PubMed

Direk, Filiz; Uysal, Ismihan Ilknur; Kivrak, Ali Sami; Fazliogullari, Zeliha; Unver Dogan, Nadire; Karabulut, Ahmet Kagan

2018-03-01

The mental foramen and lingual vascular canals are related to vessels and nerves in the mandibular body. The aim of the present study was to determine the number and location of these structures and to make measurements of them. The archived Multidetector Computed Tomography images of 100 adult (15- to 70-year-old) patients were evaluated retrospectively. The diameters of the mental foramens and their distances from the front, back, upper and lower reference points were measured. The distribution of mental foramens with respect to the teeth was also researched. The presence of lingual vascular canals, and the number of median and lateral canals was determined, and the length of the median lingual vascular canals measured. All measurement parameters were analyzed by gender, side and age group. Eleven patients demonstrated a total of 15 accessory mental foramen. Median lingual vascular canals were observed in 100% of cases, with lateral lingual vascular canals determined in 32%. Significant differences were observed in the results of different gender groups (P < 0.05); in contrast, no significant difference was observed related with age or side. Accessory mental foramen was determined mostly in males, and unilaterally on the right side; also, the distances of mental foramen, except the distance from the back border of the mandible (P < 0.05), were found to be higher, bilaterally, in males. Variation of mental foramen, as well as the presence, position and size of lingual vascular canals can be clearly investigated by multidetector computed tomography. A preoperative knowledge of the positions of neurovascular and bone structures is very important for preventing complications that may occur during or after operations.

[Mechanism of the dentino-enamel junction on the resist-crack propagation of human teeth by the finite element method].

PubMed

Jingjing, Zheng; Tiezhou, Hou; Hong, Tao; Xueyan, Guo; Cui, Wu

2014-10-01

This study aims to identify the crack tip stress intensity factor of the propagation process, crack propagation path, and the changes in the shape of the crack tip by the finite element method. The finite element model of dentino-enamel junction was established with ANSYS software, and the length of the initial crack in the single edge was set to 0.1 mm. The lower end of the sample was fixed. The tensile load of 1 MPa with frequency of 5 Hz was applied to the upper end. The stress intensity factor, deflection angle, and changes in the shape of the crack tip in the crack propagation were calculated by ANSYS. The stress intensity factor suddenly and continuously decreased in dentino-enamel junction as the crack extended. A large skewed angle appeared, and the stress on crack tip was reduced. The dentino-enamel junction on human teeth may resist crack propagation through stress reduction.

Providing a harmonious smile with laminate veneers for a patient with peg-shaped lateral incisors

PubMed Central

Alberton, Simone Beatriz; Alberton, Victória; de Carvalho, Rodrigo Varella

2017-01-01

The most common discrepancy concerning tooth size is the presence of peg-shaped lateral incisors, which can cause teeth with reduced size, anterior diastema, and consequently an unpleasant smile. The development of the adhesive dentistry and ceramic veneers allowed all ceramic-bonded restorations to become an esthetic and functional approach to reestablish the smile harmony. The purpose of this clinical report is to describe a conservative treatment approach to recover an esthetic disharmony caused by bilateral peg-shaped lateral incisors. A 30-year-old female patient was seeking treatment to solve an esthetic disharmony of her smile. Lithium disilicate veneers were planned and build-up with the help of diagnostic models, wax-up, mock-up, and silicone guides, to restore the morphology, size, function, and esthetic of upper lateral incisors and smile. The lithium disilicate veneers were able to provide the harmonization of the patient's smile, recovering the teeth size, shape, and anatomic characteristics. PMID:29279628

Providing a harmonious smile with laminate veneers for a patient with peg-shaped lateral incisors.

PubMed

Alberton, Simone Beatriz; Alberton, Victória; de Carvalho, Rodrigo Varella

2017-01-01

The most common discrepancy concerning tooth size is the presence of peg-shaped lateral incisors, which can cause teeth with reduced size, anterior diastema, and consequently an unpleasant smile. The development of the adhesive dentistry and ceramic veneers allowed all ceramic-bonded restorations to become an esthetic and functional approach to reestablish the smile harmony. The purpose of this clinical report is to describe a conservative treatment approach to recover an esthetic disharmony caused by bilateral peg-shaped lateral incisors. A 30-year-old female patient was seeking treatment to solve an esthetic disharmony of her smile. Lithium disilicate veneers were planned and build-up with the help of diagnostic models, wax-up, mock-up, and silicone guides, to restore the morphology, size, function, and esthetic of upper lateral incisors and smile. The lithium disilicate veneers were able to provide the harmonization of the patient's smile, recovering the teeth size, shape, and anatomic characteristics.

[Dento-alveolar trauma in odonto-stomatologic consultation in a health center in Yaoundé, Cameroon].

PubMed

Bengondo, M C; Toham, K A; Mbe Emane, G; Bengono, G

2007-06-01

Dento-alveolar traumatisms result from accidents concerning the oral region, and involve all sex and age groups. They have many causes. The aim of this prospective study was to assess the epidemiological profile of dento-alveolar traumatisms, considering their repartition according to age, sex, aetiologies and the more involved teeth. They represented 56.88% of maxillo-facial traumatisms seen all along the period of study. Male were more affected (72.48%) than female (27.52%). The traumatisms were more frequent between 16 and 28 years old (56.45%). With 45.16% of cases, sports were the main aetiology of these traumatisms. Teeth luxations (61.29%) and crown fracture (46.77%) were the more frequent types of traumatisms. The upper incisors were more affected. Dento-alveolar traumas are frequent and their severity depends of the traumatic agent and dento-alveolar morphology. The results of this study are comparable with those of the researches in this area all over world.

Modified protrusion arch for anterior crossbite correction - a case report.

PubMed

Roy, Abhishek Singha; Singh, Gulshan Kr; Tandon, Pradeep; Chaudhary, Ramsukh

2013-01-01

Borderline and mild skeletal Class III relationships in adult patients are usually treated by orthodontic camouflage. Reasonably rood results have been achieved with nonsurgical teatment of anterior crossbite. Class III malocclusion may be associated with mandibular prognathism, maxillary retrognathism, or both. Class III maxillary retrognathism generally involves anterior crossbite, which must be opened if upper labial brackets are to be bonded. If multiple teeth are in crossbite, after opening the bite usual step is to ligate forward or advancement arch made of 0.018" or 0.020" stainless steel or NiTi wire main arch that must be kept separated 2 mm from the slot ofupper incisor braces. Two stops or omegas are made 1 mm mesial to the tubes of the molar bands that will impede main arch from slipping,and in this manner the arch will push the anterior teeth forward Here we have fabricated a modified multiple loop protrusion arch to correct an anterior crossbite with severe crowding that was not amenable to correct by advancement arches.

Long-term stability of soft tissue changes in anterior open bite adults treated with zygomatic miniplate-anchored maxillary posterior intrusion.

PubMed

Marzouk, Eiman S; Kassem, Hassan E

2018-03-01

To evaluate soft tissue changes and their long-term stability in skeletal anterior open bite adults treated by maxillary posterior teeth intrusion using zygomatic miniplates and premolar extractions. Lateral cephalograms of 26 patients were taken at pretreatment (T1), posttreatment (T2), 1 year posttreatment (T3), and 4 years posttreatment (T4). At the end of treatment, the soft tissue facial height and profile convexity were reduced. The lips increased in length and thickness, with backward movement of the upper lip and forward movement of the lower lip. The total relapse rate ranged from 20.2% to 31.1%. At 4 years posttreatment, 68.9% to 79.8% of the soft tissue treatment effects were stable. The changes in the first year posttreatment accounted for approximately 70% of the total relapse. Soft tissue changes following maxillary posterior teeth intrusion with zygomatic miniplates and premolar extractions appear to be stable 4 years after treatment.

Fusion of the 2nd maxillary molar with the impacted 3rd molar.

PubMed

Strecha, J; Jurkovic, R; Siebert, T

2012-01-01

Subject matter: The dentist has to deal with complicated cases of fused molars, which are rather rare and morphologically very varied. A wrong or incomplete diagnosis can considerably complicate a planned therapy. The authors describe a case of apical periodontal complication of fused teeth that had to be removed surgically. The upper 2nd molar fused with the impacted 3rd molar and was diagnosed for extraction. Even a careful diagnostic procedure and X-ray image sometimes may not indicate the exact location and mutual position of the fused teeth. The authors make us aware of the possible occurrence of fused roots, and the necessity to inform the patient ahead of time about the course of endodontic or surgical interventions, possible complications and their removal. They describe the positive influence of PRP (platelet rich plasma) in wound healing. In order to establish the exact indication and therapy, they emphasize the importance of using CT imaging diagnostics or a 3D-CT examination (Fig. 7, Ref. 15).

Fox proteins are modular competency factors for facial cartilage and tooth specification.

PubMed

Xu, Pengfei; Balczerski, Bartosz; Ciozda, Amanda; Louie, Kristin; Oralova, Veronika; Huysseune, Ann; Crump, J Gage

2018-06-26

Facial form depends on the precise positioning of cartilage, bone, and tooth fields in the embryonic pharyngeal arches. How complex signaling information is integrated to specify these cell types remains a mystery. We find that modular expression of Forkhead domain transcription factors (Fox proteins) in the zebrafish face arises through integration of Hh, Fgf, Bmp, Edn1 and Jagged-Notch pathways. Whereas loss of C-class Fox proteins results in reduced upper facial cartilages, loss of F-class Fox proteins results in distal jaw truncations and absent midline cartilages and teeth. We show that Fox proteins are required for Sox9a to promote chondrogenic gene expression. Fox proteins are sufficient in neural crest-derived cells for cartilage development, and neural crest-specific misexpression of Fox proteins expands the cartilage domain but inhibits bone. These results support a modular role for Fox proteins in establishing the competency of progenitors to form cartilage and teeth in the face. © 2018. Published by The Company of Biologists Ltd.

Enhanced BMP signaling results in supernumerary tooth formation in USAG-1 deficient mouse

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

Murashima-Suginami, Akiko; Takahashi, Katsu; Sakata, Tomoko

2008-05-16

Uterine sensitization associated gene-1 (USAG-1) is a BMP antagonist, and also modulates Wnt signaling. We previously reported that USAG-1 deficient mice have supernumerary teeth. The supernumerary maxillary incisor appears to form as a result of the successive development of the rudimentary upper incisor. USAG-1 abrogation rescued apoptotic elimination of odontogenic mesenchymal cells. We confirmed that BMPs were expressed in both the epithelium and mesenchyme of the rudimentary incisor at E14 and E15. BMP signaling in the rudimentary maxillary incisor, assessed by expressions of Msx1 and Dlx2 and the phosphorylation of Smad protein, was significantly enhanced. Wnt signaling as demonstrated bymore » the nuclear localization of {beta}-catenin was also up-regulated. Inhibition of BMP signaling rescues supernumerary tooth formation in E15 incisor explant culture. Based upon these results, we conclude that enhanced BMP signaling results in supernumerary teeth and BMP signaling was modulated by Wnt signaling in the USAG-1 deficient mouse model.« less

The relationship between past caries experience and tooth color determined by an opto-electronic method.

PubMed

Kerosuo, E; Kolehmainen, L

1982-01-01

The susceptibility of a tooth to dental caries has been proposed to depend on tooth color. So far there has, however, been no reliable method for tooth color determination. The aims of this study were to evaluate the reliability of an opto-electronic method and to examine the relationship between tooth color and past caries experience. The color of upper right central incisors of 64 school-children was determined using an opto-electronic tri-stimulus color comparator. The intra- and interexaminer reliability of the method was evaluated in vitro and in vivo being 85% and 83%, respectively. To assess the past caries experience the DMFS-index was calculated. Oral hygiene and dietary habits were also assessed. No significant difference in DMFS scores was obtained between the 'white teeth' group and the 'yellow teeth' group. The conclusion is, that the practical importance of possible colorrelated differences in caries resistance is negligible due to the multifaceted nature of dental caries.

Someone's in the Kitchen, Where's Dinah? Gendered Dimensions of the Professional Culinary World

ERIC Educational Resources Information Center

Konkol, Stephanie M.

2013-01-01

Traditionally cooking is considered to be women's work, yet the vast majority of professional chefs, particularly in the upper echelons of restaurant work, are men. These curious gendered patterns stimulated interest in delving more deeply into the gendered nature of restaurant work. Existing research on this topic has concentrated on the front of…

A Model Based Analysis of the Role of an Upper-Level Front and Stratospheric Intrusion in the Mack Lake Fire

Treesearch

Tarisa K. Zimet; Jonathan E. Martin

2003-01-01

Meteorological assessment of wildfire risk has traditionally involved identification of several synoptic types empirically determined to influence wildfire spread. Such weather types are characterized by identifiable synoptic-scale structures and processes. Schroeder et. al. (1964) identified four recognizable synoptic-scale patterns that contribute most frequently to...

Predictability of orthodontic movement with orthodontic aligners: a retrospective study.

PubMed

Lombardo, Luca; Arreghini, Angela; Ramina, Fabio; Huanca Ghislanzoni, Luis T; Siciliani, Giuseppe

2017-11-13

The aim of this study was to evaluate the predictability of F22 aligners (Sweden & Martina, Due Carrare, Italy) in guiding teeth into the positions planned using digital orthodontic setup. Sixteen adult patients (6 males and 10 females, mean age 28 years 7 months) were selected, and a total of 345 teeth were analysed. Pre-treatment, ideal post-treatment-as planned on digital setup-and real post-treatment models were analysed using VAM software (Vectra, Canfield Scientific, Fairfield, NJ, USA). Prescribed and real rotation, mesiodistal tip and vestibulolingual tip were calculated for each tooth and, subsequently, analysed by tooth type (right and left upper and lower incisors, canines, premolars and molars) to identify the mean error and accuracy of each type of movement achieved with the aligner with respect to those planned using the setup. The mean predictability of movements achieved using F22 aligners was 73.6%. Mesiodistal tipping showed the most predictability, at 82.5% with respect to the ideal; this was followed by vestibulolingual tipping (72.9%) and finally rotation (66.8%). In particular, mesiodistal tip on the upper molars and lower premolars were achieved with the most predictability (93.4 and 96.7%, respectively), while rotation on the lower canines was the least efficaciously achieved (54.2%). Without the use of auxiliaries, orthodontic aligners are unable to achieve programmed movement with 100% predictability. In particular, although tipping movements were efficaciously achieved, especially at the molars and premolars, rotation of the lower canines was an extremely unpredictable movement.

Association between oral health status and central obesity among Brazilian independent-living elderly.

PubMed

Peruchi, Carla Thais Rosada; Poli-Frederico, Regina Célia; Cardelli, Alexandrina Aparecida Maciel; Fracasso, Marina de Lourdes Calvo; Bispo, Carina Gisele Costa; Neves-Souza, Rejane Dias; Cardoso, Jefferson Rosa; Maciel, Sandra Mara

2016-10-24

The aim of this study was to investigate the association between oral health status and central obesity (CO) in Brazilian independent-living elderly. A cross-sectional study was carried out in a sample of 489 elderly, who were participants of the Study on Aging and Longevity, in Londrina, state of Parana. The number of natural teeth and use of prostheses were evaluated according to the World Health Organization criteria. The presence of CO was assessed using measures of waist circumference (WC) and waist-hip ratio (WHR). Information concerning sociodemographic profile and some systemic conditions was also collected. Data were analyzed using stepwise logistic regression, α=5%. According to WC and WHR measures, the prevalence of central obesity was 79.3% and 76.1%, respectively. CO according to WC was not associated with oral status. Considering the WHR measure, the following oral conditions were associated to CO: having fewer natural teeth (OR = 2.61; 95%CI = 1.17-5.80), being edentulous and wearing both upper and lower complete dentures (OR = 2.34; 95%CI = 1.11-4.93), and being edentulous wearing only the upper complete denture (OR = 2.64; 95%CI = 1.01-6.95). Traditional risk factors for CO such as gender, dyslipidemia, hypertension and diabetes were associated with both measures. A poor oral health due to extensive tooth loss, whether partial or complete, even if rehabilitated by removable prostheses, may be considered a good predictor of CO in Brazilian independent-living elderly.

Event sand layers suggesting the possibility of tsunami deposits identified in the upper Holocene sequence nearby the Kuwana fault, central Japan

NASA Astrophysics Data System (ADS)

Niwa, Y.; Sugai, T.; Matsuzaki, H.

2012-12-01

The Kuwana fault is located on coastal area situated on inner part of the Ise Bay, central Japan, which opens to the Nankai Trough. This reverse fault displaces a late Pleistocene terrace surface with 1 to 2 mm/yr of average vertical slip rate, and a topset of delta at several meters, respectively. And, this fault is estimated to have generated two historical earthquakes (the AD 745 Tempyo and the AD 1586 Tensho earthquakes). We identified two event sand layers from upper Holocene sequence on the upthrown side of the Kuwana fault. Upper Holocene deposits in this study area show prograding delta sequence; prodelta mud, delta front sandy silt to sand, and flood plain sand/mud, respectively, from lower to upper. Two sand layers intervene in delta front sandy silt layer, respectively. Lower sand layer (S1) shows upward-coarsening succession, whereas upper sand layer (S2) upward-fining succession. These sand layers contain sharp contact, rip-up crust, and shell fragment, indicating strong stream flow. Radiocarbon ages show that these strong stream flow events occurred between 3000 and 1600 years ago. Decreasing of salinity is estimated from decreasing trend of electrical conductivity (EC) across S1. Based on the possibility that decreasing of salinity can be occurred by shallowing of water depth caused by coseismic uplift, and that S1 can be correlated with previously known faulting event on the Kuwana fault, S1 is considered to be tsunami deposits caused by faulting on the Kuwana fault. On the other hand, S2, which cannot be correlated with previously known faulting events on the Kuwana fault, may be tsunami deposits by ocean-trench earthquake or storm deposits. In the presentation, we will discuss more detail correlation of these sand deposits not only in the upthrown side of the Kuwana fault, but also downthrown side of the fault.

Rugged Iris Mechanism

NASA Technical Reports Server (NTRS)

Ferragut, Nelson J.

2005-01-01

A rugged iris mechanism has been designed to satisfy several special requirements, including a wide aperture in the "open" position, full obscuration in the "closed" position, ability to function in a cryogenic or other harsh environment, and minimization of friction through minimization of the number of components. An important element of the low-friction aspect of the design is maximization of the flatness of, and provision of small gaps between, adjacent iris blades. The tolerances of the design can be very loose, accommodating thermal expansions and contractions associated with large temperature excursions. The design is generic in that it is adaptable to a wide range of aperture sizes and can be implemented in a variety of materials to suit the thermal, optical, and mechanical requirements of various applications. The mechanism (see figure) includes an inner flat ring, an outer flat ring, and an even number of iris blades. The iris blades shown in front in the figure are denoted as "upper," and the iris blades shown partly hidden behind the front ones are denoted as "lower." Each iris blade is attached to the inner ring by a pivot assembly and to the outer ring by a roller/slider assembly. The upper and lower rings are co-centered and are kept in sliding contact. The iris is opened or closed by turning the outer ring around the center while holding the inner ring stationary. The mechanism is enclosed in a housing (not shown in the figure) that comprises an upper and a lower housing shell. The housing provides part of the sliding support for the outer ring and keeps the two rings aligned as described above. The aforementioned pivot assemblies at the inner ring also serve as spacers for the housing. The lower housing shell contains part of the lower sliding surface and features for mounting the overall mechanism and housing assembly. The upper housing shell contains part of the upper sliding surface.

The Use of Tooth Particles as a Biomaterial in Post-Extraction Sockets. Experimental Study in Dogs.

PubMed

Calvo-Guirado, José Luis; Maté-Sánchez de Val, José Eduardo; Ramos-Oltra, María Luisa; Pérez-Albacete Martínez, Carlos; Ramírez-Fernández, María Piedad; Maiquez-Gosálvez, Manuel; Gehrke, Sergio A; Fernández-Domínguez, Manuel; Romanos, Georgios E; Delgado-Ruiz, Rafael Arcesio

2018-05-06

Objectives : The objective of this study was to evaluate new bone formation derived from freshly crushed extracted teeth, grafted immediately in post-extraction sites in an animal model, compared with sites without graft filling, evaluated at 30 and 90 days. Material and Methods : The bilateral premolars P2, P3, P4 and the first mandibular molar were extracted atraumatically from six Beagle dogs. The clean, dry teeth were ground immediately using the Smart Dentin Grinder. The tooth particles obtained were subsequently sieved through a special sorting filter into two compartments; the upper container isolating particles over 1200 μm, the lower container isolated particles over 300 μm. The crushed teeth were grafted into the post-extraction sockets at P3, P4 and M1 (test group) (larger and smaller post-extraction alveoli), while P2 sites were left unfilled and acted as a control group. Tissue healing and bone formation were evaluated by histological and histomorphometric analysis after 30 and 90 days. Results : At 30 days, test site bone formation was greater in the test group than the control group ( p < 0.05); less immature bone was observed in the test group (25.71%) than the control group (55.98%). At 90 days, significant differences in bone formation were found with more in the test group than the control group. No significant differences were found in new bone formation when comparing the small and large alveoli post-extraction sites. Conclusions : Tooth particles extracted from dog’s teeth, grafted immediately after extractions can be considered a suitable biomaterial for socket preservation.

Treatment of endo-periodontal lesion using leukocyte-platelet-rich fibrin. A case report

PubMed Central

Elgueta, Ricardo; Fuentes, Ramon

2017-01-01

Abstract Case Description: The main objective of this paper was to report the clinical effectiveness of leukocyte- platelet- rich fibrin (L-PRF) in the treatment of a combined endo-periodontal lesion of an upper first premolar. Clinical Findings: The tooth had a profound abfraction on the vestibular aspect and presented no mobility but revealed a deep pocket measuring of 11 mm on the mesial vestibular aspect and 14 mm on the mesial palatine aspect. The three dimensional image analysis showed total bone loss in the mesial aspect and an extensively bone loss of the vestibular aspect of the vestibular root. Treatment and Outcome: Endodontic treatment was performed and periodontal access surgery (surgical periodontal therapy) was done with the application of autologous L-PRF. Three month and 6 months after surgery, the cone beam computed tomography (CBCT) exams showed no bone regeneration in any aspect of the tooth. However, periodontal examination showed a significative improvement in the deepness of surcus. The mesial vestibular aspect had a deep pocket of 3 mm and 5 mm on the mesial palatine aspect showing a reduction in deepness of 8 mm and 9 mm, respectively. Clinical Relevance: The actual treatment for teeth with bad prognosis is the extraction and replacement with implants. Even though implants are capable of restore function and aesthetic, the abuse of this approach have led to the loss of teeth that could be successfully treated with a less invasive technique. The prognosis of teeth with endoperiodontal lesion is poor but could be enhanced with regenerative therapies. Until now there are no clinical trials and just four case report about the treatment of these teeth with platelet rich fibrin. PMID:29662262

Impact of untreated dental caries and its clinical consequences on the oral health-related quality of life of schoolchildren aged 8-10 years.

PubMed

Mota-Veloso, Isabella; Soares, Maria Eliza C; Alencar, Bruna Mota; Marques, Leandro Silva; Ramos-Jorge, Maria Letícia; Ramos-Jorge, Joana

2016-01-01

This study aims to evaluate the impact of untreated dental caries and its clinical consequences on the quality of life of Brazilian schoolchildren aged 8-10 years. A randomly selected sample of 587 children underwent a clinical oral examination for the assessment of untreated dental caries and clinical consequences. The WHO criteria (decayed component of the decayed, missing, and filled teeth--D-DMFT in permanent teeth or d-dfmt in primary teeth) and the PUFA index, which records the presence of severely decayed permanent (upper case) and primary (lower case) teeth with visible pulpal involvement (P/p), as well as ulceration caused by dislocated tooth fragments (U/u), fistula (F/f), and abscesses (A/a), were used for the oral examination. Oral health-related quality of life (OHRQoL) was evaluated using the Child's Perception Questionnaire (CPQ8-10). Poisson regression was employed to test unadjusted and adjusted associations between untreated dental caries/clinical consequences and OHRQoL. The prevalence of untreated dental caries was 64.6% (D/d component of DMFT/dmft > 0) and 17.9% of children exhibited clinical consequences of caries (PUFA/pufa index >0). In the adjusted models, untreated caries was significantly associated with the total CPQ8-10 score and all subscale scores. The clinical consequences of dental caries (PUFA/pufa index >0) were significantly associated with the total CPQ8-10 as well as the oral symptoms and functional limitations' subscales. Untreated dental caries and its clinical consequences exerted a negative impact on the OHRQoL of the schoolchildren analyzed.

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

PubMed Central

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

2006-01-01

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

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

PubMed

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

2006-04-01

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

Comparison of the oropharyngeal cavity in the Starksiini (Teleostei: Blenniiformes: Labrisomidae): taste buds and teeth, including a comparison with closely-related genera.

PubMed

Fishelson, Lev; Baldwin, Carole C; Hastings, Philip A

2012-06-01

The present study describes the distribution of taste buds and teeth in the oropharyngeal cavity of 13 species of adult (18-60 mm SL) Starksiini fishes inhabiting subtidal waters of the Neotropical region. Four types of taste buds described previously in other fish groups were observed within the oropharyngeal cavity, of which type I, situated on prominent protruding papillae, is the most common. The number of taste buds in this cavity varies considerably, ranging from ca. 202 in Starksia lepicoelia to ca. 770 in S. sluiteri. In all the studied species, taste buds are more numerous on the posterior (160-396) than on the anterior (42-294) part of the oropharyngeal cavity. The presence of different numbers of taste buds in different Starksiini species of the same standard length suggests that numbers of taste buds are not directly correlated with size and may be species-specific. Teeth are found on the premaxilla, dentary, vomer, palatine (in some species) and the upper and lower pharyngeal jaws (third pharyngobranchials and fifth ceratobranchials, respectively); the form and number of teeth and taste buds on each of these sites differs among the various species of Starksiini and between them and closely related species of the labrisomid tribes Labrisomini, Mnierpini, and Paraclinini. The results thus suggest potential systematic value in certain features of the oropharyngeal cavity for blenniiform fishes. It is also shown that benthic-feeding omnivorous fishes have higher densities of taste buds than piscivorous fishes. A possible correlation among numbers of taste buds, their positions in the oropharyngeal cavity, and other parameters is discussed. Copyright © 2012 Wiley Periodicals, Inc.

Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians

PubMed Central

Kear, Benjamin P.; Larsson, Dennis; Lindgren, Johan; Kundrát, Martin

2017-01-01

Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing ‘fangs’. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2–3 years–other polyphyodont amniotes normally take ~1–2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation. PMID:28241059

Morphologic evaluation of dentoalveolar structures of mandibular anterior teeth during augmented corticotomy-assisted decompensation.

PubMed

Ahn, Hyo-Won; Seo, Dong-Hwi; Kim, Seong-Hun; Park, Young-Guk; Chung, Kyu-Rhim; Nelson, Gerald

2016-10-01

Our aim in this study was to evaluate the effect of augmented corticotomy on the decompensation pattern of mandibular anterior teeth, alveolar bone, and surrounding periodontal tissues during presurgical orthodontic treatment. Thirty skeletal Class III adult patients were divided into 2 groups according to the application of augmented corticotomy labial to the anterior mandibular roots: experimental group (with augmented corticotomy, n = 15) and control group (without augmented corticotomy, n = 15). Lateral cephalograms and cone-beam computed tomography images were taken before orthodontic treatment and before surgery. The measurements included the inclination and position of the mandibular incisors, labial alveolar bone area, vertical alveolar bone height, root length, and alveolar bone thickness at 3 levels surrounding the mandibular central incisors, lateral incisors, and canines. The mandibular incisors were significantly proclined in both groups (P <0.001); however, the labial movement of the incisor tip was greater in the experimental group (P <0.05). Significant vertical alveolar bone loss was observed only in the control group (P <0.001). The middle and lower alveolar thicknesses and labial alveolar bone area increased in the experimental group. In the control group, the upper and middle alveolar thicknesses and labial alveolar bone area decreased significantly. There were no significant differences in dentoalveolar changes between the 3 kinds of anterior teeth in each group, except for root length in the experimental group (P <0.05). Augmented corticotomy provided a favorable decompensation pattern of the mandibular incisors, preserving the periodontal structures surrounding the mandibular anterior teeth for skeletal Class III patients. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Role of lower hybrid waves in ion heating at dipolarization fronts

NASA Astrophysics Data System (ADS)

Greco, A.; Artemyev, A.; Zimbardo, G.; Angelopoulos, V.; Runov, A.

2017-05-01

One of the important sources of hot ions in the magnetotail is the bursty bulk flows propagating away from the reconnection region and heating the ambient plasma. Charged particles interact with nonlinear magnetic field pulses (dipolarization fronts, DFs) embedded into these flows. The convection electric fields associated with DF propagation are known to reflect and accelerate ambient ions. Moreover, a wide range of waves is observed within/near these fronts, the electric field fluctuations being dominated by the lower hybrid drift (LHD) instability. Here we investigate the potential role of these waves in the further acceleration of ambient ions. We use a LHD wave emission profile superimposed on the leading edge of a two-dimensional model profile of a DF and a test particle approach. We show that LHD waves with realistic amplitudes can significantly increase the upper limit of energies gained by ions. Wave-particle interaction near the front is more effective in producing superthermal ions than in increasing the flux of thermal ions. Comparison of test particle simulations and Time History of Events and Macroscale Interactions during Substorms observations show that ion acceleration by LHD waves is more important for slower DFs.

Chlorine dioxide-induced and Congo red-inhibited Marangoni effect on the chlorite-trithionate reaction front

NASA Astrophysics Data System (ADS)

Liu, Yang; Ren, Xingfeng; Pan, Changwei; Zheng, Ting; Yuan, Ling; Zheng, Juhua; Gao, Qingyu

2017-10-01

Hydrodynamic flows can exert multiple effects on an exothermal autocatalytic reaction, such as buoyancy and the Marangoni convection, which can change the structure and velocity of chemical waves. Here we report that in the chlorite-trithionate reaction, the production and consumption of chlorine dioxide can induce and inhibit Marangoni flow, respectively, leading to different chemo-hydrodynamic patterns. The horizontal propagation of a reaction-diffusion-convection front was investigated with the upper surface open to the air. The Marangoni convection, induced by gaseous chlorine dioxide on the surface, produced from chlorite disproportionation after the proton autocatalysis, has the same effect as the heat convection. When the Marangoni effect is removed by the reaction of chlorine dioxide with the Congo red (CR) indicator, an oscillatory propagation of the front tip is observed under suitable conditions. Replacing CR with bromophenol blue (BPB) distinctly enhanced the floating, resulting in multiple vortexes, owing to the coexistence between BPB and chlorine dioxide. Using the incompressible Navier-Stokes equations coupled with reaction-diffusion and heat conduction equations, we numerically obtain various experimental scenarios of front instability for the exothermic autocatalytic reaction coupled with buoyancy-driven convection and Marangoni convection.

Cold Fronts Research Programme: Progress, Future Plans, and Research Directions.

NASA Astrophysics Data System (ADS)

Ryan, B. F.; Wilson, K. J.; Garratt, J. R.; Smith, R. K.

1985-09-01

Following the analysis of data collected during Phases land II of the Cold Fronts Research Programme (CFRP) a conceptual model for the Australian summertime "cool change" has been proposed. The model provides a focus and a framework for the design of Phase III.The model is based on data gathered from a mesoscale network centered on Mount Gambier, South Australia, and includes the coastal waters to the west and relatively flat terrain to the east. The first objective of Phase III is to generalize the model so that it is applicable to the ocean waters to the far west of Mount Gambier and to the more rugged terrain farther to the east in the vicinity of Melbourne, Victoria. The remaining objectives concentrate on resolving unsatisfactory aspects of the model such as the evolution of convective lines and the relationship between the surface cold front and the upper-tropospheric cold pool and its associated jet stream.The integrated nature of the Cold Fronts Research Programme has meant that it has stimulated a wide range of research activities that extend beyond the field observations. The associated investigations include climatological, theoretical, and numerical modeling studies.

Antenna induced hot restrike of a ceramic metal halide lamp recorded by high-speed photography

NASA Astrophysics Data System (ADS)

Hermanns, P.; Hoebing, T.; Bergner, A.; Ruhrmann, C.; Awakowicz, P.; Mentel, J.

2016-03-01

The hot restrike is one of the biggest challenges in operating ceramic metal halide lamps with mercury as buffer gas. Compared to a cold lamp, the pressure within a ceramic burner is two orders of magnitude higher during steady state operation due to the high temperature of the ceramic tube and the resulting high mercury vapour pressure. Room temperature conditions are achieved after 300 s of cooling down in a commercial burner, enclosed in an evacuated outer bulb. At the beginning of the cooling down, ignition voltage rises up to more than 14 kV. A significant reduction of the hot-restrike voltage can be achieved by using a so called active antenna. It is realized by a conductive sleeve surrounding the burner at the capillary of the upper electrode. The antenna is connected to the lower electrode of the lamp, so that its potential is extended to the vicinity of the upper electrode. An increased electric field in front of the upper electrode is induced, when an ignition pulse is applied to the lamp electrodes. A symmetrically shaped ignition pulse is applied with an amplitude, which is just sufficient to re-ignite the hot lamp. The re-ignition, 60 s after switching off the lamp, when the mercury pressure starts to be saturated, is recorded for both polarities of the ignition pulse with a high-speed camera, which records four pictures within the symmetrically shaped ignition pulse with exposure times of 100 ns and throws of 100 ns. The pictures show that the high electric field and its temporal variation establish a local dielectric barrier discharge in front of the upper electrode inside the burner, which covers the inner wall of the burner with a surface charge. It forms a starting point of streamers, which may induce the lamp ignition predominantly within the second half cycle of the ignition pulse. It is found out that an active antenna is more effective when the starting point of the surface streamer in front of the sleeve is a negative surface charge on the inner tube wall. The high-speed photos show that the ignition process is very similar in lamps with Hg or Xe as buffer gas.

The Weddell-Scotia Confluence in midwinter

NASA Astrophysics Data System (ADS)

Muench, Robin D.; Gunn, John T.; Husby, David M.

1990-10-01

The southern central Scotia Sea, site of the Weddell-Scotia Confluence where outflowing Weddell Sea waters converge with the eastward flowing waters of the Scotia Sea, was sampled during June-August (austral winter) 1988 with respect to temperature and salinity. Both drogued and ice-mounted drifters, tracked by Argos, were deployed in the region and yielded Lagrangian drift tracks of ice and water motion. The data substantiate past accounts of the region, based upon summer field research, as dominated by eastward flow upon which a complex array of mesoscale features is superimposed. Weddell-Scotia Confluence Water, documented by past summer work in the region and characterized by decreased static stability, was not detected, and the Scotia Front was not well defined. The region was one of intense mixing activity and primarily anticyclonic mesoscale features. Two such features, one an eddy and the other either an eddy or a meander in the Scotia Front, dominated the mesoscale field. With warm cores and containing Polar Front Water, they may have been advected eastward from Drake Passage or may have formed as detached eddies from a sharp northward bend in the Polar Front which typically lies just west of the study region. Several smaller eddies, primarily anticyclonic and some having warm cores, were also detected. There was no evidence of the deep convective mixing which has been hypothesized, on the basis of past summer data, to occur in winter, and vigorous vertical mixing was limited to a 100-m-thick upper mixed layer. Vertical stability in the upper layers was enhanced by low-salinity water derived from melting ice. Temperature-salinity analyses show that winter water in the study region can be derived through isopycnal mixing between waters from the Scotia Sea and waters from the northwestern Weddell Sea. This is in apparent contrast with summer conditions, wherein conditioning of water either through vertical mixing or via lateral mixing on continental margins has been invoked to arrive at the water mass characteristics which typify the Weddell-Scotia Confluence.

Caries prevalence among schoolchildren in Zagreb, Croatia

PubMed Central

Dukić, Walter; Delija, Barbara; Lulić Dukić, Olga

2011-01-01

Aim To investigate the prevalence of dental caries and treatment needs in schoolchildren aged 7-14 years from Zagreb. Methods Dental examinations based on the World Health Organization criteria were performed on 1168 children in the period 2009-2010. The teeth were clinically examined with standard dental instruments using visual-tactile method under standard dental light. We recorded the clinical indexes of decayed, missed, and filled teeth (DMFT and dmft; upper-case letters refer to permanent and lower-case letters to primary teeth) and decayed, missed, and filled surfaces (DMFS), as well as the significant caries index (SiC). Results The median DMFT and DMFS of all children were 3 and 4, respectively. The median DMFT and DMFS of 12-year-old children were 4 and 5, respectively. The highest median DMFT score of 7 was found among 14-year-old children. There was a significant difference between age groups (7-10 years and 11-14 years) in DMFT and DMFS. Among 8-year-old children, the median dmft index was the highest (5.5) and SiC index was 7.4. As far as the location of caries on the surface of the first permanent molar is concerned, caries occurred mostly in the central occlusal surface (27.6%). Conclusion Our results showed a high caries prevalence among schoolchildren in Zagreb, indicating a need for an extensive program of primary oral health care. PMID:22180264

Caries prevalence among schoolchildren in Zagreb, Croatia.

PubMed

Dukić, Walter; Delija, Barbara; Lulić Dukić, Olga

2011-12-15

To investigate the prevalence of dental caries and treatment needs in schoolchildren aged 7-14 years from Zagreb. Dental examinations based on the World Health Organization criteria were performed on 1168 children in the period 2009-2010. The teeth were clinically examined with standard dental instruments using visual-tactile method under standard dental light. We recorded the clinical indexes of decayed, missed, and filled teeth (DMFT and dmft; upper-case letters refer to permanent and lower-case letters to primary teeth) and decayed, missed, and filled surfaces (DMFS), as well as the significant caries index (SiC). The median DMFT and DMFS of all children were 3 and 4, respectively. The median DMFT and DMFS of 12-year-old children were 4 and 5, respectively. The highest median DMFT score of 7 was found among 14-year-old children. There was a significant difference between age groups (7-10 years and 11-14 years) in DMFT and DMFS. Among 8-year-old children, the median dmft index was the highest (5.5) and SiC index was 7.4. As far as the location of caries on the surface of the first permanent molar is concerned, caries occurred mostly in the central occlusal surface (27.6%). Our results showed a high caries prevalence among schoolchildren in Zagreb, indicating a need for an extensive program of primary oral health care.

Evaluation of the performance of orthodontic devices using FBG sensors

NASA Astrophysics Data System (ADS)

Carvalho, L.; Roriz, P.; Frazão, O.; Marques, M. B.

2015-04-01

Cross-bite, as a malocclusion effect, is defined as a transversal changing of the upper dental arch, in relation to the lower arch, and may be classified as skeletal, dental or functional. As a consequence, the expansion of maxilla is an effective clinical treatment used to correct transversal maxillary discrepancy. The maxillary expansion is an ancient method used in orthodontics, for the correction of the maxillary athresia with posterior crossbite, through the opening of the midpalatal suture (disjunction), using orthodontic- orthopaedic devices. Same controversial discussion arises among the clinicians, about the effects of each orthodontic devices as also about the technique to be employed. The objective of this study was to compare the strain field induced by two different orthodontic devices, named disjunctor with and without a connecting bar, in an acrylic model jaw, using fiber Bragg grating sensors to measure the strain patterns. The orthodontic device disjunctor with the bar, in general, transmits higher forces and strain to teeth and maxillae, than with the disjunctor without bar. It was verified that the strain patterns were not symmetric between the left and the right sides as also between the posterior and anterior regions of the maxillae. For the two devices is also found that in addition a displacement in the horizontal plane, particularly in posterior teeth, also occurs a rotation corresponding to a vestibularization of the posterior teeth and their alveolar processes.

Saurida lessepsianus a new species of lizardfish (Pisces: Synodontidae) from the Red Sea and Mediterranean Sea, with a key to Saurida species in the Red Sea.

PubMed

Russell, Barry C; Golani, Daniel; Tikochinski, Yaron

2015-05-12

Saurida lessepsianus n. sp., a lizardfish (Aulopiformes: Synodontidae) from the Red Sea and Mediterranean Sea, previously misidentified as S. undosquamis (Richardson) and more recently as S. macrolepis Tanaka, is described as a new species. It is characterised by the following combination of characters: dorsal fin with 11-12 rays; pectoral fins with 13-15 rays; lateral-line scales 47-51; transverse scale rows above lateral line 4½, below lateral line 5½; pectoral fins moderately long (extending to between just before or just beyond a line from origin of pelvic fins to origin of dorsal fin); 2 rows of teeth on outer palatines; 0-2 teeth on vomer; tongue with 3-6 rows of teeth posteriorly; caudal peduncle slightly compressed (depth a little more than width); upper margin of caudal fin with row of 3-8 (usually 6 or 7) small black spots; stomach pale grey to blackish anteriorly; intestine whitish. The species is common in the Red Sea and as a result of Lessepsian migration through the Suez Canal, it is now widely distributed in the eastern Mediterranean. The taxonomic status of two other Red Sea nominal species, Saurus badimottah Rüppell [= Saurida tumbil (Bloch)] and Saurida sinaitica Dollfus in Gruvel (a nomen nudum), is clarified. A key is provided for the species of Saurida in the Red Sea.

Dental caries is common in Finnish children infected with Helicobacter pylori.

PubMed

Kolho, K L; Hölttä, P; Alaluusua, S; Lindahl, H; Savilahti, E; Rautelin, H

2001-01-01

Childhood factors such as low socioeconomic status are risk factors for Helicobacter pylori infection and Streptococcus mutans-related dental caries. We examined whether H. pylori infection and dental caries are present today in the same group of children examined previously. We reviewed the public dental health service files of 21 H. pylori-positive children (upper gastrointestinal endoscopy at a median age of 13.5 y) and 27 H. pylori-negative children (endoscopy at a median age of 12.5 y) examined during 1995-98 at the Helsinki University Central Hospital, Finland. All H. pylori-positive children had experienced dental caries in their primary or permanent teeth or in both whereas among H. pylori-negative children the respective proportion was 70% (p < 0.01). At the age of 7 y, 18% (3/17) of the H. pylori-positive children had experienced caries in permanent teeth as compared to 0% among H. pylori-negative children (0/24; p < 0.05). At the age of 12 y, H. pylori-positive children had more decayed, missing or filled permanent teeth than H. pylori-negative children (80% vs. 38%; p < 0.05). Although a causal relationship between H. pylori and dental caries is unlikely, it is possible that H. pylori-infected children have an increased risk of other health problems, such as dental caries, for which proper treatment is needed.

The dynamics of oceanic fronts. Part 1: The Gulf Stream

NASA Technical Reports Server (NTRS)

Kao, T. W.

1970-01-01

The establishment and maintenance of the mean hydrographic properties of large scale density fronts in the upper ocean is considered. The dynamics is studied by posing an initial value problem starting with a near surface discharge of buoyant water with a prescribed density deficit into an ambient stationary fluid of uniform density. The full time dependent diffusion and Navier-Stokes equations for a constant Coriolis parameter are used in this study. Scaling analysis reveals three independent length scales of the problem, namely a radius of deformation or inertial length scale, Lo, a buoyance length scale, ho, and a diffusive length scale, hv. Two basic dimensionless parameters are then formed from these length scales, the thermal (or more precisely, the densimetric) Rossby number, Ro = Lo/ho and the Ekman number, E = hv/ho. The governing equations are then suitably scaled and the resulting normalized equations are shown to depend on E alone for problems of oceanic interest. Under this scaling, the solutions are similar for all Ro. It is also shown that 1/Ro is a measure of the frontal slope. The governing equations are solved numerically and the scaling analysis is confirmed. The solution indicates that an equilibrium state is established. The front can then be rendered stationary by a barotropic current from a larger scale along-front pressure gradient. In that quasisteady state, and for small values of E, the main thermocline and the inclined isopycnics forming the front have evolved, together with the along-front jet. Conservation of potential vorticity is also obtained in the light water pool. The surface jet exhibits anticyclonic shear in the light water pool and cyclonic shear across the front.

Space-borne observation of mesospheric bore by Visible and near Infrared Spectral Imager onboard the International Space Station

NASA Astrophysics Data System (ADS)

Hozumi, Y.; Saito, A.; Sakanoi, T.; Yamazaki, A.; Hosokawa, K.

2017-12-01

Mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in O2 airglow at 762 nm wavelength. The mesospheric bore is moving front of sharp jump followed by undulations or turbulence in the mesopause region. Since previous studies of mesospheric bore were mainly based on ground-based airglow imaging that is limited in field-of-view and observing site, little is known about its horizontal extent and global behavior. Space-borne imaging by ISS-IMAP/VISI provides an opportunity to study the mesospheric bore with a wide field-of-view and global coverage. A mesospheric bore was captured by VISI in two consecutive paths on 9 July 2015 over the south of African continent (48ºS - 54ºS and 15ºE). The wave front aligned with south-north direction and propagated to west. The phase velocity and wave length of the following undulation were estimated to 100 m/s and 30 km, respectively. Those parameters are similar to those reported by previous studies. 30º anti-clockwise rotation of the wave front was recognized in 100 min. Another mesospheric bore was captured on 9 May 2013 over the south Atlantic ocean (35ºS - 43ºS and 24ºW - 1ºE) with more than 2,200 km horizontal extent of wave front. The wave front aligned with southeast-northwest direction. Because the following undulation is recognized in the southwest side of the wave front, it is estimated to propagate to northeast direction. The wave front was modulated with 1,000 km wave length. This modulation implies inhomogeneity of the phase velocity.

Mapping and quantifying sediment transfer between the front of rapidly moving rock glaciers and torrential gullies

NASA Astrophysics Data System (ADS)

Kummert, Mario; Delaloye, Reynald

2018-05-01

The sedimentary connection which may occur between the front of active rock glaciers and torrential channels is not well understood, despite its potential impact on the torrential activity characterizing the concerned catchments. In this study, DEMs of difference (DoDs) covering various time intervals between 2013 and 2016 were obtained from LiDAR-derived multitemporal DEMs for three rapidly moving rock glaciers located in the western Swiss Alps. The DoDs were used to map and quantify sediment transfer activity between the front of these rock glaciers and the corresponding underlying torrential gullies. Sediment transfer rates ranging between 1500 m3/y and 7800 m3/y have been calculated, depending on the sites. Sediment eroded from the fronts generally accumulated in the upper sectors of the torrential gullies where they were occasionally mobilized within small to medium sized debris flow events. A clear relation between the motion rates of the rock glaciers and the sediment transfer rates calculated at their fronts could be highlighted. Along with the size of the frontal areas, rock glacier creep rates influence thus directly sediment availability in the headwaters of the studied torrents. The frequency-magnitude of debris flow events varied between sites and was mainly related to the concordance of local factors such as topography, water availability, sediment availability or sediment type.

Dental caries and dental fluorosis among 4-, 6-, 12- and 15-year-old children in kindergartens and public schools in Kuwait.

PubMed

Vigild, M; Skougaard, M; Hadi, R A; al-Zaabi, F; al-Yasseen, I

1996-03-01

The purpose of the present study was 1) to describe the occurrence of dental caries and fluorosis among children in kindergartens and public schools in Kuwait, and determine their need for dental health care, 2) to describe changes in caries prevalence and experience from 1982 to 1993 and 3) to provide a baseline for the evaluation of the preventive oral health programmes starting in Kuwait in 1994. The study population comprised 3,500 4-, 6-, 12- and 15-year-old children in kindergartens and public schools in Kuwait, selected by stratified cluster sampling. Dental caries was scored by surface in accordance with WHO criteria, and dental fluorosis was registered by Dean's index (modified). The mean deft was 4.6 at age 4 years, and 6.2 at age 6; 8 and 11 percent of the decay had been treated by extractions or fillings in the two respective age groups. Among the 6-, 12- and 15-year-old children DMFT was 0.2, 2.6 and 3.6 respectively; 12 and 14 percent of the decayed teeth of 12- and 15-year-old children had been treated. As to the 4- and 6-year-old children, 19 and 9 percent were caries-free in the deciduous teeth, while 86, 21 and 14 percent of the 6-, 12- and 15-year-old children were caries-free in the permanent teeth. Among the 4-year-old children 47 percent had caries in the front teeth. None of the children had severe dental fluorosis, but 6 percent at 12 and 15 years showed mild to moderate, but manifest, dental fluorosis. The survey revealed that caries experience as well as caries prevalence had increased since 1982, although there was a marked increase in the number of filled tooth surfaces in all age cohorts. However, in 1993 the DMFT of 12-year-old children was still well within WHO's global goal for the year 2000, whereas the prevalence of dental caries among 6-year-old was considerably higher than the WHO goal.

Geologic map of the Bailey 30' x 60' quadrangle, North-Central Colorado

USGS Publications Warehouse

Ruleman, Chester A.; Bohannon, Robert G.; Bryant, Bruce; Shroba, Ralph R.; Premo, Wayne R.

2011-01-01

The Bailey, Colo. 1:100,000-scale quadrangle lies within two physiographic and geologic provinces in central Colorado: 1) the Front Range and 2) South Park. Most of the Front Range is composed of Proterozoic rocks ranging in age from 1,790 Ma to 1,074 Ma. Along the eastern flanks and within the Denver Basin, sedimentary rocks ranging from Pennsylvanian to Cretaceous are deformed and steeply tilted to the east. Upper Cretaceous through Paleocene rocks were deposited in the foreland (that is, the Front Range eastern flank) and hinterland (that is, South Park) of this thrust and reverse fault system developed during the Late Cretaceous to Paleocene Laramide orogeny. Within South Park, rocks range in age from Pennsylvanian to Miocene with Quaternary deposits indicating tectonic subsidence of the basin. These rocks record five major geologic episodes: 1) the Paleozoic Anasazi uplift that formed the Ancestral Rockies, 2) the Late Cretaceous to Paleocene Laramide orogeny, 3) widespread Eocene to Oligocene volcanism, 4) Oligocene-Quaternary tectonics, and 5) Quaternary glacial episodes.

The dynamics of oceanic fronts. I - The Gulf Stream

NASA Technical Reports Server (NTRS)

Kao, T. W.

1980-01-01

The establishment and maintenance of the mean hydrographic properties of large-scale density fronts in the upper ocean is considered. The dynamics is studied by posing an initial value problem starting with a near-surface discharge of buoyant water with a prescribed density deficit into an ambient stationary fluid of uniform density; full time dependent diffusion and Navier-Stokes equations are then used with constant eddy diffusion and viscosity coefficients, together with a constant Coriolis parameter. Scaling analysis reveals three independent scales of the problem including the radius of deformation of the inertial length, buoyancy length, and diffusive length scales. The governing equations are then suitably scaled and the resulting normalized equations are shown to depend on the Ekman number alone for problems of oceanic interest. It is concluded that the mean Gulf Stream dynamics can be interpreted in terms of a solution of the Navier-Stokes and diffusion equations, with the cross-stream circulation responsible for the maintenance of the front; this mechanism is suggested for the maintenance of the Gulf Stream dynamics.

Upper Campanian suspected silicified seismite related to the Syrian Arc tectonic system in the Middle East

NASA Astrophysics Data System (ADS)

Lewy, Zeev

2010-06-01

The formation of the rare 'homogenous linear structures' in chert beds in the Phosphate Member of the Mishash Formation in central and southern Israel is reevaluated based on new samples from Har Omer, Arava Valley. These are of 4-6 cm thick chert beds in which the upper and lower surfaces form dense subparallel low ridges in contrast to the planar surfaces of other chert layers alternating with other lithologies. The ridges were suggested to have formed by advancing silicification fronts replacing the original sediment by microquartz without specifying the control on the ridged pattern and its regional orientation. One sample exhibits different color internal folds attesting to a multiple wavy mobilization of the silica-bearing liquid, probably composed of individual tiny crystallites of silicified calcareous micrite dispersed in seawater. This interpreted 'soup' of microquartz crystallites is corroborated by examples of a plastic deformation and mobilization in a muddy state of the siliceous Mishash Formation unconsolidated sediment. E-W dominant orientation of the ridges in central and southern Israel cannot be related to a simple diffusive diagenetic process and probably was initiated by N-S trending seismic surface waves during the Syrian Arc tectonic activity in the Middle East. Accordingly, this seismically induced sedimentary structure (seismite) formed through the vertical mobilization of silica-rich liquid replacing seawater in-between the sedimentary particles, advancing in a wavy upper and lower front triggered by a seismic event.

Dental age assessment of young Iranian adults using third molars: A multivariate regression study.

PubMed

Bagherpour, Ali; Anbiaee, Najmeh; Partovi, Parnia; Golestani, Shayan; Afzalinasab, Shakiba

2012-10-01

In recent years, a noticeable increase in forensic age estimations of living individuals has been observed. Radiologic assessment of the mineralisation stage of third molars is of particular importance, with regard to the relevant age group. To attain a referral database and regression equations for dental age estimation of unaccompanied minors in an Iranian population was the goal of this study. Moreover, determination was made concerning the probability of an individual being over the age of 18 in case of full third molar(s) development. Using the scoring system of Gleiser and Hunt, modified by Köhler, an investigation of a cross-sectional sample of 1274 orthopantomograms of 885 females and 389 males aged between 15 and 22 years was carried out. Using kappa statistics, intra-observer reliability was tested. With Spearman correlation coefficient, correlation between the scores of all four wisdom teeth, was evaluated. We also carried out the Wilcoxon signed-rank test on asymmetry and calculated the regression formulae. A strong intra-observer agreement was displayed by the kappa value. No significant difference (p-value for upper and lower jaws were 0.07 and 0.59, respectively) was discovered by Wilcoxon signed-rank test for left and right asymmetry. The developmental stage of upper right and upper left third molars yielded the greatest correlation coefficient. The probability of an individual being over the age of 18 is 95.6% for males and 100.0% for females in case four fully developed third molars are present. Taking into consideration gender, location and number of wisdom teeth, regression formulae were arrived at. Use of population-specific standards is recommended as a means of improving the accuracy of forensic age estimates based on third molars mineralisation. To obtain more exact regression formulae, wider age range studies are recommended. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

New Specimens of the Rare Taeniodont Wortmania (Mammalia: Eutheria) from the San Juan Basin of New Mexico and Comments on the Phylogeny and Functional Morphology of “Archaic” Mammals

PubMed Central

Williamson, Thomas E.; Brusatte, Stephen L.

2013-01-01

Background Taeniodonta is a clade of Late Cretaceous – Paleogene mammals remarkable for their relatively extreme cranial, dental, and postcranial adaptations and notable for being among the first mammals to achieve relatively large size following the Cretaceous-Paleogene mass extinction. Previous workers have hypothesized that taeniodonts can be divided into two clades: Conoryctidae, a group of small-bodied taeniodonts with supposedly “generalized” postcranial skeletons, and Stylinodontidae, a group of large-bodied, robust animals with massive forelimbs and claws adapted for scratch-digging. However, many taeniodont taxa are poorly known and few are represented by postcranial material, leaving many details about their anatomy, biology, and evolution ambiguous. Methodology/Principal Findings In this paper, we describe three new specimens of the rare taxon Wortmaniaotariidens from the early Paleocene (Puercan) of New Mexico. Among these specimens is one that includes remarkably complete cranial and dental material, including associated upper and lower teeth, and another that consists of partial forelimbs. These specimens allow for an updated anatomical description of this unusual taxon, supply new data for phylogenetic analyses, and enable a more constrained discussion of taeniodont biology and functional morphology. Conclusions/Significance The new specimen of Wortmania that includes associated upper and lower teeth indicates that previous interpretations of the upper dentition of this taxon were not accurate and the taxon Robertschochiasullivani is a junior synonym of W . otariidens . New specimens that include partial forelimbs indicate that Wortmania is very similar to later, large-bodied taeniodonts, with marked and distinctive adaptations for scratch-digging. Comparisons with other taeniodont taxa that include postcranial material suggest that all taeniodonts may have had scratch-digging adaptations. A phylogenetic analysis shows that Schowalteria and Onychodectes are basal taeniodonts, Stylinodontidae (including Wortmania) is monophyletic, and a monophyletic Conoryctidae (but not including Onychodectes) is only recovered when certain characters are ordered. PMID:24098738

New specimens of the rare taeniodont Wortmania (Mammalia: Eutheria) from the San Juan Basin of New Mexico and comments on the phylogeny and functional morphology of "archaic" mammals.

PubMed

Williamson, Thomas E; Brusatte, Stephen L

2013-01-01

Taeniodonta is a clade of Late Cretaceous-Paleogene mammals remarkable for their relatively extreme cranial, dental, and postcranial adaptations and notable for being among the first mammals to achieve relatively large size following the Cretaceous-Paleogene mass extinction. Previous workers have hypothesized that taeniodonts can be divided into two clades: Conoryctidae, a group of small-bodied taeniodonts with supposedly "generalized" postcranial skeletons, and Stylinodontidae, a group of large-bodied, robust animals with massive forelimbs and claws adapted for scratch-digging. However, many taeniodont taxa are poorly known and few are represented by postcranial material, leaving many details about their anatomy, biology, and evolution ambiguous. In this paper, we describe three new specimens of the rare taxon Wortmania otariidens from the early Paleocene (Puercan) of New Mexico. Among these specimens is one that includes remarkably complete cranial and dental material, including associated upper and lower teeth, and another that consists of partial forelimbs. These specimens allow for an updated anatomical description of this unusual taxon, supply new data for phylogenetic analyses, and enable a more constrained discussion of taeniodont biology and functional morphology. The new specimen of Wortmania that includes associated upper and lower teeth indicates that previous interpretations of the upper dentition of this taxon were not accurate and the taxon Robertschochia sullivani is a junior synonym of W. otariidens. New specimens that include partial forelimbs indicate that Wortmania is very similar to later, large-bodied taeniodonts, with marked and distinctive adaptations for scratch-digging. Comparisons with other taeniodont taxa that include postcranial material suggest that all taeniodonts may have had scratch-digging adaptations. A phylogenetic analysis shows that Schowalteria and Onychodectes are basal taeniodonts, Stylinodontidae (including Wortmania) is monophyletic, and a monophyletic Conoryctidae (but not including Onychodectes) is only recovered when certain characters are ordered.

3D enamel thickness in Neandertal and modern human permanent canines.

PubMed

Buti, Laura; Le Cabec, Adeline; Panetta, Daniele; Tripodi, Maria; Salvadori, Piero A; Hublin, Jean-Jacques; Feeney, Robin N M; Benazzi, Stefano

2017-12-01

Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Bridging the Gap: Capturing the Lyα Counterpart of a Type-II Spicule and Its Heating Evolution with VAULT2.0 and IRIS Observations

NASA Astrophysics Data System (ADS)

Chintzoglou, Georgios; De Pontieu, Bart; Martínez-Sykora, Juan; Pereira, Tiago M. D.; Vourlidas, Angelos; Tun Beltran, Samuel

2018-04-01

We present results from an observing campaign in support of the VAULT2.0 sounding rocket launch on 2014 September 30. VAULT2.0 is a Lyα (1216 Å) spectroheliograph capable of providing spectroheliograms at high cadence. Lyα observations are highly complementary to the IRIS observations of the upper chromosphere and the low transition region (TR) but have previously been unavailable. The VAULT2.0 data provide new constraints on upper-chromospheric conditions for numerical models. The observing campaign was closely coordinated with the IRIS mission. Taking advantage of this simultaneous multi-wavelength coverage of target AR 12172 and by using state-of-the-art radiative-MHD simulations of spicules, we investigate in detail a type-II spicule associated with a fast (300 km s‑1) network jet recorded in the campaign observations. Our analysis suggests that spicular material exists suspended high in the atmosphere but at lower temperatures (seen in Lyα) until it is heated and becomes visible in TR temperatures as a network jet. The heating begins lower in the spicule and propagates upwards as a rapidly propagating thermal front. The front is then observed as fast, plane-of-the-sky motion typical of a network jet, but contained inside the pre-existing spicule. This work supports the idea that the high speeds reported in network jets should not be taken as real mass upflows but only as apparent speeds of a rapidly propagating heating front along the pre-existing spicule.

Fluid flow and reaction fronts: characterization of physical processes at the microscale using SEM analyses

NASA Astrophysics Data System (ADS)

Beaudoin, Nicolas; Koehn, Daniel; Toussaint, Renaud; Gomez-Rivas, Enrique; Bons, Paul; Chung, Peter; Martín-Martín, Juan Diego

2014-05-01

Fluid migrations are the principal agent for mineral replacement in the upper crust, leading to dramatic changes in the porosity and permeability of rocks over several kilometers. Consequently, a better understanding of the physical parameters leading to mineral replacement is required to better understand and model fluid flow and rock reservoir properties. Large-scale dolostone bodies are one of the best and most debated examples of such fluid-related mineral replacement. These formations received a lot of attention lately, and although genetic mechanics and implications for fluid volume are understood, the mechanisms controlling the formation and propagation of the dolomitization reaction front remain unclear. This contribution aims at an improvement of the knowledge about how this replacement front propagates over space and time. We study the front sharpness on hand specimen and thin section scale and what the influence of advection versus diffusion of material is on the front development. In addition, we demonstrate how preexisting heterogeneities in the host rock affect the propagation of the reaction front. The rock is normally not homogeneous but contains grain boundaries, fractures and stylolites, and such structures are important on the scale of the front width. Using Scanning Electron Microscopy and Raman Spectroscopy we characterized the reaction front chemistry and morphology in different context. Specimens of dolomitization fronts, collected from carbonate sequences of the southern Maestrat Basin, Spain and the Southwestern Scottish Highlands suggest that the front thickness is about several mm being relatively sharp. Fluid infiltrated grain boundaries and fractures forming mm-scale transition zone. We study the structure of the reaction zone in detail and discuss implications for fluid diffusion-advection models and mineral replacement. In addition we formulate a numerical model taking into account fluid flow, diffusion and advection of the mobile reactive species, reaction rates, disorder in the location of the potential replacement seeds, and permeability heterogeneities. The goal of this model is to compare the shape of the resulting patterns, notably in terms of thickness, and eventually roughness or fractal dimension.

Changes in the Circum-Alpine Climate as a Function of the Alpine Upliftment: Constraints from Isotopic Compositions of Fossils, Sediments, and Vein Quartz

NASA Astrophysics Data System (ADS)

Vennemann, T. W.; Tutken, T.; Kocsis, L.; Mullis, J.

2005-12-01

The Tertiary circum-Alpine Molasse sediments were deposited during major periods of Alpine tectonism but also at a time of large global climatic change. They are well suited to study the effects of tectonic forcing on climate, because the sediments were deposited in marginal basins, partly to completely isolated from other major oceanic basins. Hence, a comparison of the past climatic and oceanographic evolution indicated by the sediments to those on a global scale, does allow for a qualitative evaluation of the relationship between tectonism and regional climate. Much is known about the geological-geochronological framework of alpine tectonism, including associated erosional rates and sediment volumes. Estimates of changes in paleoelevation and its direct influence on climate have, however, been less well constrained. Three independent lines of evidence indicate significant altitudes of the Alps during the Miocene: 1) H isotope compositions of clay minerals, formed as weathering products and subsequently deposited as part of the Alpine Molasse, have δD reaching values as low as -97‰. 2) O isotope compositions of retrograde metamorphic vein and fissure quartz and H isotope composition of its included fluids have δ18O values as low as -3.5‰ and δD values of -140‰, respectively. 3) ``Exotic" shark teeth from Swiss Upper Marine Molasse sediments that have δ18O values (VSMOW) around 11‰ (n=2), values unlike those from other teeth of the same locality (20.7 to 21.8‰; n=6), but for which the REE patterns support the same diagenetic history, hence supporting a freshwater formation of the low δ18O teeth (also supported by distinct Sr isotope compositions). Using these three approaches as a basis for estimating the isotopic composition of past precipitation and applying the present-day altitude effects on the compositions, it can be concluded that the Miocene Alps had mean altitudes of about 1500 to 2000 m, that is elevations similar to those of today. Paleoclimatic reconstructions from North Alpine Molasse sediments are based on oxygen isotope compositions of fossil mammalian tooth enamel for freshwater molasse deposits, and shark teeth, marine ostracoda, foraminifera, and mammalian phosphatic fossils for the Upper Marine Molasse deposits. The δ18O values (VPDB) of carbonate in phosphate from Oligocene and Miocene large mammal teeth (n=270), for example, vary over a large range from -11.9‰ to -0.5‰, but these variations parallel the composite O isotope curve of Tertiary benthic foraminifera, thus reflecting major global climatic changes such as the Late Oligocene warming, Mid-Miocene climate optimum, and Middle to Late Miocene cooling trends. The δ18O values (VSMOW) of phosphate in shark teeth (19.8 to 23.3‰; n=130) from Miocene marine molasse sediments as well as those of ostracods and foraminifera from these sediments all have variations that parallel those of composite curves for global changes. Collectively, the data support a Neogene paleogeography with a high mountain belt adjacent to marginal marine or freshwater depositional basins but with a regional climate, at least for the northern Molasse realm, that was strongly coupled to the global climate. The Alps thus appear not have influenced the local climate and/or atmospheric circulation patterns significantly.

Abnormal tooth development in a sea lamprey

USGS Publications Warehouse

Manion, Patrick J.; Hanson, Lee H.

1977-01-01

Sea lampreys en route to their spawning grounds have been captured at mechanical or electrical structures that have been in operation for 1 to 27 spawning seasons (1949-75) on some 167 tributaries of the upper Great Lakes; more than 750,000 were taken in 1949-70 (Smith 1971). Among these lampreys (all of which were routinely examined at the time of capture) was one female (length, 434 mm; weight, 130 g) with markedly underdeveloped teeth. It was captured in May 1968 at an electrical barrier in the Ocqueoc River, a Michigan tributary of Lake Huron

An ictidosaur fossil from north america.

PubMed

Chatterjee, S

1983-06-10

Teeth of a North American ictidosaur, Pachygenelus milleri, n. sp., found in the Upper Triassic Dockum Group of Texas, indicate that it is very similar to Pachygenelus monus of South Africa and Chaliminia musteloides of South America. The presence of a Gondwana element in the Northern Hemisphere attests to the ease of dispersal of the Late Triassic vertebrates through Pangea. Ictidosaurs are small, highly advanced, carnivorous cynodonts that display a mosaic of reptilian and mammalian features in the masticatory apparatus. They were contemporaneous with early mammals and probably closely related to them.

Lidar for Lateral Mixing (LATMIX)

DTIC Science & Technology

2013-09-30

overflew, a strong reflection front he float could be detected in the lidar elastic backscatter channel. Initial searches have detected several liar...grid scale mixing and stirring in numerical models. Ultimately our research will also enhance modeling and understanding of upper ocean ecosystems...km. A second objective is to determine whether slow but persistent vortices enhance the stirring attributable to shear dispersion. We also share

Lidar for Lateral Mixing (LATMIX)

DTIC Science & Technology

2012-09-30

strong reflection front he float could be detected in the lidar elastic backscatter channel. Initial searches have detected several liar float returns...stirring in numerical models. Ultimately our research will also enhance modeling and understanding of upper ocean ecosystems, since the flow of...is to determine whether slow but persistent vortices enhance the stirring attributable to shear dispersion. We also share the overall objectives of

Rehabilitating slash pile burn scars in upper montane forests of the Colorado Front Range

Treesearch

Paula J. Fornwalt; Charles C. Rhoades

2011-01-01

Slash pile burning is widely conducted by land managers to dispose of unwanted woody fuels, yet this practice typically has undesirable ecological impacts. Simple rehabilitation treatments may be effective at ameliorating some of the negative impacts of pile burning on plants and soils. Here, we investigated: (1) the impacts of slash pile burning on soil nitrogen and...

6. Workers laying up the graphite core of the 105B ...

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

6. Workers laying up the graphite core of the 105-B file. In the lower-left can be seen a portion of the rear face of the pile, the top of its shielding wall, and the gun barrels protruding through it. The inside of the front face of the pile and its gun barrels can be seen toward the upper-right side. The angled top of the front shielding wall can be seen in the picture. All four walls were "stepped" in this manner where they joined with another wall or the ceiling to form a "labyrinth" joint, so that radiation would not have a straight route through any gaps in the joints. D-3045 - B Reactor, Richland, Benton County, WA

The Transantarctic Mountains of southern Victoria Land: The application of Apatite fission track analysis to a rift shoulder uplift

NASA Astrophysics Data System (ADS)

Fitzgerald, Paul G.

1992-06-01

A fission track study of the Transantarctic Mountains (TAM) in the Granite Harbour and Wilson Piedmont Glacier areas of southern Victoria Land reveals information on the timing of uplift, the amount of uplift and erosion, and the structure of the mountains, especially the onshore Transantarctic Mountain Front (TAM Front), which represents the boundary between East and West Antarctica. Apatite ages are < 175 Ma and represent a thermal regime established after heating accompanying Jurassic magmatism. An apatite age profile from Mount England records a break in slope indicating uplift began at ˜55 Ma. Horizontal sampling traverses, plus fieldwork, delineate the structure of the TAM Front as a zone of north-south striking, steeply dipping normal faults, with displacements, dominantly down to the east, of 40-1000 m. The overall structure of the mountains in the area studied can be envisaged as a large tilt block or flexure. Its westerly limb dips gently under the ice cap, compared to its faulted eastern edge, the TAM Front. The bounding structure to the south is the Ferrar fault and to the north is a graben through which the Mackay Glacier drains the polar plateau. The edge of the flexure, or axis of maximum uplift, lies at Mount Termination, ˜30 km west of the McMurdo Sound coast. There has been ˜6 km of uplift since the early Cenozoic and 4.5-5 km of erosion along this axis. The amount of uplift decreases to the west at the same rate as the decrease in dip of the Kukri Peneplain, but the amount of erosion decreases more quickly as indicated by the increasing height of the mountains to the west. The axis of maximum uplift is traced north to Granite Harbour. The axis does not parallel the coast but has a more northerly trend. North-south striking longitudinal faults that delineate the structure of the TAM Front lie at an acute angle to the axis, indicating a dextral component to the dominantly east-west extension in the Ross Embayment. Architecture of the TAM typifies the features of an upper plate passive mountain range, whereas the Ross Embayment has the characteristics of a lower plate. The TAM Front represents an upper plate breakaway zone. Transfer faults may exist up major outlet glaciers that cut the TAM. The inflection point in the coastline at the southern end of McMurdo Sound may be due to the presence of a major transfer fault up or near the Skelton Glacier.

Analysis of the golden proportion and width/height ratios of maxillary anterior dentition in patients with lateral incisor agenesis.

PubMed

Pini, Núbia Pavesi; de-Marchi, Luciana Manzotti; Gribel, Bruno Frazão; Ubaldini, Adriana Lemos Mori; Pascotto, Renata Corrêa

2012-12-01

  The purpose of this study was to assess the presence of the golden proportion (GP) in the facial view tooth-to-tooth width proportion of the six maxillary anterior teeth and to evaluate the width/height (W/H) ratios of the incisors of patients with maxillary lateral incisor (LI) agenesis treated either with implants or orthodontically (by moving canines into the position of the laterals, recontouring them, and placing composite restorations over the repositioned teeth).   Forty-eight patients with LI agenesis were divided into four experimental groups: unilateral recontouring group (N = 10), bilateral recontouring group (BRG, N = 18), unilateral implant group (UIG, N = 10), bilateral implant group (N = 10), and a control group (CG, N = 25) of patients without agenesis. GP ratios were determined on patients' dental casts placed over Levin's grids, whereas W/H ratios were measured directly on the casts and a millimeter ruler to determine these distances. Statistical analysis was performed with Shapiro-Wilk, Kruskal-Wallis, Mann-Whitney, Friedman, and Wilcoxon tests (p < 0.05).   The incidence of GP in the tooth-to-tooth width proportions was significantly different between groups and more commonly found between centrals and laterals than between laterals and canines. The GP was more likely to be observed in the BRG, UIG, and CG. The results demonstrated that the GP was not found to be present in the majority of the cases treated with maxillary agenesis, regardless of the method of treatment. The mean W/H ratios of the laterals ranged between 0.75 and 0.90.   Although the GP may be a useful diagnostic guide, it was not observed in the majority of esthetic outcomes of patients treated with maxillary LI agenesis in this study. The assessment of the golden proportion and width/height ratio of upper anterior teeth in patients with upper lateral incisor agenesis treated with either implants or tooth re-contouring may assist dentists and patients in deciding the best treatment option based on the peculiarities of each case. © 2012 Wiley Periodicals, Inc.

Vertical force and torque analysis during mechanical preparation of extracted teeth using hand ProTaper instruments.

PubMed

Glavičić, Snježana; Anić, Ivica; Braut, Alen; Miletić, Ivana; Borčić, Josipa

2011-08-01

The purpose was to measure and analyse the vertical force and torque developed in the wider and narrower root canals during hand ProTaper instrumentation. Twenty human incisors were divided in two groups. Upper incisors were experimental model for the wide, while the lower incisors for the narrow root canals. Measurements of the force and torque were done by a device constructed for this purpose. Differences between the groups were statistically analysed by Mann-Whitney U-test with the significance level set to P<0.05. Vertical force in the upper incisors ranged 0.25-2.58 N, while in the lower incisors 0.38-6.94 N. Measured torque in the upper incisors ranged 0.53-12.03 Nmm, while in the lower incisor ranged 0.94-10.0 Nmm. Vertical force and torque were higher in the root canals of smaller diameter. The increase in the contact surface results in increase of the vertical force and torque as well in both narrower and wider root canals. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

Dental erosion and severe tooth decay related to soft drinks: a case report and literature review*

PubMed Central

Cheng, Ran; Yang, Hui; Shao, Mei-ying; Hu, Tao; Zhou, Xue-dong

2009-01-01

Soft drinks have many potential health problems. The inherent acids and sugars have both acidogenic and cariogenic potential, resulting in dental caries and potential enamel erosion. In this report we present a 25-year-old man complaining with the severe worn-out of the front teeth during the past 3 years. He had a history of drinking cola for more than 7 years and had a poor oral hygiene. Severe decays were present in the incisors and the canines, while less severe lesions were noted on the premolars and the molars. The review is to show the relationship between dental erosion and caries and soft drinks. Some efforts have been taken to reduce the harmful effect of soft drinks. PMID:19434767

Measurement and modeling of temperature distribution for Er:YAG laser root canal sterilization

NASA Astrophysics Data System (ADS)

Hibst, Raimund; Stock, Karl; Keller, Ulrich

1999-02-01

Based on the bactericidal effect of subablative irradiation the Er:YAG laser can be used for root canal sterilization in endodontics. For this, an optical fiber will be inserted into the root canal down to a depth of about 1 mm in front of the apex, and then removed while activating the laser. In order to avoid heat accumulation which could be harmful to the desmodont or periodont, repetition rate and fiber withdrawal velocity must be kept within certain limits. These limits were determined by calculations based on a 1-dim, cylindrical model and related temperature measurements on half cutted teeth. The calculations agree well to the control measurements and are used to derive a complete set of application parameters in dependence on the expected root thickness.

Removable orthodontic appliance with nickel-titanium spring to reposition the upper incisors in an autistic patient.

PubMed

Saito, Kan; Jang, Insan; Kubota, Kazumi; Hoshino, Tomonori; Hotokezaka, Hitoshi; Yoshida, Noriaki; Fujiwara, Taku

2013-01-01

A newly designed removable appliance with a shape-memory wire was used for the orthodontic treatment of the anterior teeth in an 11-year-old child who had autism and intellectual disability. The device was designed to reduce the lateral incisor crossbite and the central incisors' labial rotation. The child was treated for 1 year with this removable appliance. Tooth movement was analyzed using cephalograms and surface data were derived from study models. This device proved to be very durable. The lateral incisor crossbite was corrected, and the inclination of the upper central incisors and the interincisal angle were improved. This appliance exerts light and continuous orthodontic force, without requiring any adjustments of the spring wire. The appliance also facilitated orthodontic treatment in a child with intellectual disability in whom treatment with a standard orthodontic device would be unsuitable. ©2012 Special Care Dentistry Association and Wiley Periodicals, Inc.

Corticotomy-assisted orthodontic camouflage in a class III adult patient with a severe transverse discrepancy.

PubMed

Gracco, Antonio; Finotti, Marco; Bruno, Giovanni; de Stefani, Alberto

2018-04-06

A 25-year-old man presented with a maxillary transverse discrepancy, posterior cross bite, anterior open bite, molar and canine class III. Treatment included a corticotomy in the upper lateral and posterior teeth, a palatal expansor and a sectional archwire to assist the expansion. The following treatment phase included bonding with Incognito System lingual appliance, interproximal reduction to solve the crowding and bite blocks to control the verticality. Two months after the bonding intermaxillary class III elastics were used to solve the sagittal discrepancy and eight months after the bonding vertical elastics were used in order to solve the anterior open bite until the end of the treatment. A Boston splint was applied for the upper arch, an essix splint was applied for the lower arch. The patient compliance was an essential aspect in the success of the orthodontic treatment. Copyright © 2018. Published by Elsevier Masson SAS.

An Intense Traveling Airglow Front in the Upper Mesosphere-Lower Thermosphere with Characteristic of a Turbulent Bore Observed over Alice Springs, Australia

NASA Astrophysics Data System (ADS)

Walterscheid, R. L.; Hecht, J. H.; Hickey, M. P.; Gelinas, L. J.; Vincent, R. A.; Reid, I. M.; Woithe, J.

2010-12-01

The Aerospace Corporation’s Nightglow Imager observed a large step-function change in airglow in the form of a traveling front in the OH and O2 airglow emissions over Alice Springs Australia on February 2, 2003. The front exhibited a stepwise increase of nearly a factor two in the OH brightness and a stepwise decrease in the O2 brightness. The change in brightness in each layer was associated with a strong leading disturbance followed by a train of weak barely visible waves. The OH airglow brightness behind the front was the brightness night for 02 at Alice Springs that we have measured in seven years of observations. The OH brightness was among the five brightest. The event was associated with a strong phase-locked two-day wave (TDW).We have analyzed the stability conditions for the upper mesosphere and lower thermosphere and found that the airglow layers were found in a region of strong ducting. The thermal structure was obtained from combining data from the SABER instrument on the TIMED satellite and the NRLMSISE-00 model. The wind profile was obtained by combining the HWM07 model and MF radar winds from Buckland Park Australia. We found that the TDW-disturbed profile was significantly more effective in supporting a high degree of ducting than a profile based only on HWM07 winds. Dramatic wall events have been interpreted as manifestations of undular bores (e.g., Smith et al. [2003]). Undular bores are nonlinear high Froude number events that must generate an ever increasing train of waves to carry the excess energy away from the bore front. Only a very weak wave train behind the initial disturbance was seen for the Alice Springs event. The form of the amplitude ordering was not typical of a nonlinear wave train. Therefore a bore interpretation requires another means of energy dissipation, namely turbulent dissipation. We suggest that a reasonable interpretation of the observed event is a turbulent bore. We are unaware of any previous event having characteristics of a turbulent bore. Smith, S. M., et al., A multidiagnostic investigation of the mesospheric bore phenomenon, J. Geophys. Res., 108, 2003

Dental bleaching on teeth submitted to enamel microabrasion 30 years ago-a case report of patients' compliance during bleaching treatment.

PubMed

Sundfeld, Daniel; Pavani, Caio Cesar; Schott, Timm Cornelius; Machado, Lucas Silveira; Pini, Núbia Inocêncya Pavesi; Bertoz, André Pinheiro de Magalhães; Sundfeld, Renato Herman

2018-04-20

The present dental bleaching case report describes a new method that precisely quantifies the daily wearing-times of the bleaching product by inserting a microsensor in the acetate custom tray. The bleaching efficacy was also discussed since the patient was previously submitted to enamel microabrasion. The patient was submitted to enamel microabrasion in 1987, and bleaching treatment was performed in 2005. In 2017, re-bleaching was executed using 10% peroxide carbamide. The electronic microsensor, TheraMon (TheraMon® microelectronic system; Sales Agency Gschladt, Hargelsberg, Austria), was embedded in the labial region of the upper and lower acetate trays to evaluate the wearing-times of the acetate trays/bleaching product. The patient was instructed to wear the tray for 6 to 8 h/day while sleeping. After 24 days of bleaching treatment, the data obtained from the TheraMon electronic devices was collected and interpreted. The patient did not entirely follow the bleaching treatment as recommended, as there was no evidence of use of the upper and lower trays for some days; additionally, the bleaching product was used for shorter and longer periods than was instructed. The TheraMon microeletronic device precisely measured the wearing-times of the acetate tray/bleaching product during the bleaching treatment. Teeth submitted to enamel microabrasion presented with a healthy clinical appearance after 30 years. Measuring the length and frequency of use of an acetate tray/bleaching product can be important to clinicians and patients for obtaining a controlled and adequate bleaching treatment.

Angle Class I malocclusion treated with lower incisor extraction.

PubMed

Barbosa, Vanessa Leal Tavares

2013-01-01

In planning orthodontic cases that include extractions as an alternative to solve the problem of negative space discrepancy, the critical decision is to determine which teeth will be extracted. Several aspects must be considered, such as periodontal health, orthodontic mechanics, functional and esthetic alterations, and treatment stability. Despite controversies, extraction of teeth to solve dental crowding is a therapy that has been used for decades. Premolar extractions are the most common, but there are situations in which atypical extractions facilitate mechanics, preserve periodontal health and favor maintenance of the facial profile, which tends to unfavorably change due to facial changes with age. The extraction of a lower incisor, in selected cases, is an effective approach, and literature describes greater post-treatment stability when compared with premolar extractions. This article reports the clinical case of a patient with Angle Class I malocclusion and upper and lower anterior crowding, a balanced face and harmonious facial profile. The presence of gingival and bone recession limited large orthodontic movements. The molars and premolars were well occluded, and the discrepancy was mainly concentrated in the anterior region of the lower dental arch. The extraction of a lower incisor in the most ectopic position and with compromised periodontium, associated with interproximal stripping in the upper and lower arches, was the alternative of choice for this treatment, which restored function, providing improved periodontal health, maintained facial esthetics and allowed finishing with a stable and balanced occlusion. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO), as part of the requirements for obtaining the BBO Diplomate title.

The Philippines in a Changing Southeast Asia

DTIC Science & Technology

1989-03-01

financing loans and in providing shelter , pect from their governments. In this century, the have mainly benefited the upper half of the income state has...national policies, employment and capital; educates and socializes the young; assures medical care; shelters its hand- Cultural Limits to Political and ...Liberation Front, the Muslim In- of yellow clothing, ribbons, and party banners was dependence Liberation Army, the Cordillera a conscious symbolic appeal

Generation of large-scale intrusions at baroclinic fronts: an analytical consideration with a reference to the Arctic Ocean

NASA Astrophysics Data System (ADS)

Kuzmina, Natalia

2016-12-01

Analytical solutions are found for the problem of instability of a weak geostrophic flow with linear velocity shear accounting for vertical diffusion of buoyancy. The analysis is based on the potential-vorticity equation in a long-wave approximation when the horizontal scale of disturbances is considered much larger than the local baroclinic Rossby radius. It is hypothesized that the solutions found can be applied to describe stable and unstable disturbances of the planetary scale with respect, in particular, to the Arctic Ocean, where weak baroclinic fronts with typical temporal variability periods on the order of several years or more have been observed and the β effect is negligible. Stable (decaying with time) solutions describe disturbances that, in contrast to the Rossby waves, can propagate to both the west and east, depending on the sign of the linear shear of geostrophic velocity. The unstable (growing with time) solutions are applied to explain the formation of large-scale intrusions at baroclinic fronts under the stable-stable thermohaline stratification observed in the upper layer of the Polar Deep Water in the Eurasian Basin. The suggested mechanism of formation of intrusions can be considered a possible alternative to the mechanism of interleaving at the baroclinic fronts due to the differential mixing.

A quantitative evaluation of the high elbow technique in front crawl.

PubMed

Suito, Hiroshi; Nunome, Hiroyuki; Ikegami, Yasuo

2017-07-01

Many coaches often instruct swimmers to keep the elbow in a high position (high elbow position) during early phase of the underwater stroke motion (pull phase) in front crawl, however, the high elbow position has never been quantitatively evaluated. The aims of this study were (1) to quantitatively evaluate the "high elbow" position, (2) to clarify the relationship between the high elbow position and required upper limb configuration and (3) to examine the efficacy of high elbow position on the resultant swimming velocity. Sixteen highly skilled and 6 novice male swimmers performed 25 m front crawl with maximal effort and their 3-dimensional arm stroke motion was captured at 60 Hz. An attempt was made to develop a new index to evaluate the high elbow position (I he : high elbow index) using 3-dimensional coordinates of the shoulder, elbow and wrist joints. I he of skilled swimmers moderately correlated with the average shoulder internal rotation angle (r = -0.652, P < 0.01) and swimming velocity (r = -0.683, P < 0.01) during the pull phase. These results indicate that I he is a useful index for evaluating high elbow arm stroke technique during the pull phase in front crawl.

Flows in the Tasman Front south of Norfolk Island

NASA Astrophysics Data System (ADS)

Sutton, Philip J. H.; Bowen, Melissa

2014-05-01

The Tasman Front is a narrow band of eastward flowing subtropical water crossing the Tasman Sea from Australia to North Cape, New Zealand. It is the link between the two subtropical western boundary currents of the South Pacific, the East Australian Current (EAC) off eastern Australia, and the East Auckland Current (EAUC) off northeastern New Zealand. Here we report the first direct measurements of flow in the Tasman Front from a moored array deployed across gaps in the submarine ridges south of Norfolk Island and hydrographic and ADCP measurements during the deployment and recovery voyages. The mean flow through the array over July 2003 to August 2004 was found to be eastward only in the upper 800 m with a transport of ˜6 Sv. Below 800 m a weak westward mean flow (˜1.5 Sv) was measured, associated with Antarctic Intermediate Water (AAIW). Using sea surface height to account for additional transport south of the moored array results in a total mean eastward transport between Norfolk Island and North Cape, New Zealand of ˜8 Sv, varying between -4 and 18 Sv. The measurements show that the Tasman Front is much shallower than either the EAC or EAUC, both of which extend below 2000 m depth, has less transport than either the EAC or EAUC and has instances of flow reversal. Thus, the Tasman Front is a weaker connection between the EAC and EAUC than the paradigm of a contiguous South Pacific western boundary current system would suggest.

Crown heights in the permanent teeth of 45,X and 45,X/46,XX females.

PubMed

Pentinpuro, Raija Helena; Lähdesmäki, Raija Eliisa; Niinimaa, Ahti Olavi; Pesonen, Paula Ritva Orvokki; Alvesalo, Lassi Juhani

2014-11-01

Previous results regarding human sex chromosome aneuploidies have shown that the X and Y chromosomes affect tooth size and morphology. This study looked for the effect of sex chromosome deficiency on permanent tooth crown heights. The material, from the Finnish KVANTTI Research Project, consisted of 97 45,X females and 15 45,X/46,XX females. The controls were 32 sisters and 28 mothers of the 45,X females, eight sisters and two mothers of the 45,X/46,XX females and 35 female population controls. Crown heights of all the available teeth except third molars on both sides of the jaws were measured from panoramic radiographs with a digital calliper according to the defined procedure. The tooth crown heights were significantly smaller in the 45,X females than in the female population controls, except for the incisors and one canine in the maxilla, whereas the tooth crown heights of the 45,X/46,XX females were close to those of the normal control females. The differences between the 45,X and 45,X/46,XX females were statistically significant, excluding the upper incisor area and a few teeth in the mandible. The effect of the sex chromosome deficiency on permanent tooth crown height is due to the magnitude of lacking sex chromosome material. The present results regarding the 45,X females are parallel to previous findings in Turner patients regarding reduced mesiodistal and labiolingual dimensions and tooth crown heights in the permanent dentition.

Determination of vertical dimension of occlusion in dentate patients by cephalometric analysis--pilot study.

PubMed

Tavano, Karine T A; Seraidarian, Paulo I; de Oliveira, Dauro D; Jansen, Wellington C

2012-06-01

The concept of vertical dimension of occlusion (VDO) refers to a measure in the vertical plane that establishes the relation between the maxilla and the mandible when the posterior teeth, both from the maxillary and from the mandibular arches, are occluded, regardless of whether they are natural or prosthetic, healthy or restored. This measure is subject to change, and when this occurs, it can compromise both the function and the facial aesthetics. This study proposed to develop a methodology based on cephalometric analysis by studying the 31 lateral teleradiographs of adult, dentate individuals to determine the VDO, based on bone structures that are not dependent on the presence or absence of posterior teeth. The final goal was to make this application accessible to individuals who have undergone alterations of the lower portion of the face. The cephalometric analysis of this study, called Seraidarian-Tavano, was verified through facial angles (upper and middle angles) that, when correlated, determine the lower position of the face. The analysis of results showed that no statistically significant difference between the angles studied could be observed (superior angle 50.29 ± 3.35 e median angle 49.95 ± 3.37). In the same manner, no variation in the results regarding gender in the measure of these angles could be observed. This cephalometric analysis can be applied to determine the VDO, regardless of the presence or absence of posterior teeth. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Immunohistochemical expression of hard tissue related factors in the mouse dental pulp after immediate teeth separation

PubMed Central

2011-01-01

We examined change of Runx2 and ALP expression in mouse tooth pulp which exposed to teeth separation experiment by immunohistochemistry as a model for conservative dentistry treatment. 8-week-old 36 male ddY mice were used and wedge was inserted between upper 1st and 2nd molars. The wedge was removed 30 minutes as well as 3 hours after the insertion and the samples were prepared extending up to 1 week of time period for regular histopathological and immunohistochemical examinations for ALP and Runx2 expression. The opposite sides without wedge insertion were taken as controls. In the control group pulp, weak expressions of Runx2 and ALP in the vessel endothelial cells as well as the pulp cells were revealed, suggesting the appearance of these genes upon mechanical stress induced by mastication and tongue pressure etc. On the other hand in the experiment group, Runx2 expression increased both in 30-minute and 3-hour teeth separation group. The expression became maximum at 24 hours. Then it gradually decreased and became similar level with the control group at 1-week after the wedge insertion. Similarly ALP expression increased after the wedge insertion and was maximum at 24 hours and then gradually decreased to the levels similar with the control group. These results suggest that when immunohistochemical expression of Runx2 as well as ALP was used as an index, no severe damage occur upon clinical application of wedge insertion. PMID:22027645

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. © 2010 Wiley Periodicals, Inc.

Extracellular Matrix-mediated Tissue Remodeling Following Axial Movement of Teeth

PubMed Central

Luan, Xianghong; Ito, Yoshihiro; Holliday, Sean; Walker, Cameron; Daniel, Jon; Galang, Therese M.; Fukui, Tadayoshi; Yamane, Akira; Begole, Ellen; Evans, Carla; Diekwisch, Thomas G.H.

2007-01-01

SUMMARY Tooth eruption is a multifactorial process involving movement of existing tissues and formation of new tissues coordinated by a complex set of genetic events. We have used the model of the unopposed rodent molar to study morphological and genetic mechanisms involved in axial movement of teeth. Following extraction of opposing upper molars, lower molars supererupted by 0.13 mm. Labeled tissue sections revealed significant amounts of new bone and cementum apposition at the root apex of the unopposed side following supereruption for 12 days. Newly apposited cementum and alveolar bone layers were approximately 3-fold thicker in the experimental vs the control group, whereas periodontal ligament width was maintained. Tartrate-resistant acid phosphatase staining indicated bone resorption at the mesial alveolar walls of unopposed molars and provided in tandem with new bone formation at the distal alveolar walls an explanation for the distal drift of molars in this model. Microarray analysis and semiquantitative RT-PCR demonstrated a significant increase in collagen I, integrin β5, and SPARC gene expression as revealed by comparison between the unopposed molar group and the control group. Immunohistochemical verification revealed increased levels of integrin β5 and SPARC labeling in the periodontal ligament of the unopposed molar. Together our findings suggest that posteruptive axial movement of teeth was accomplished by significant formation of new root cementum and alveolar bone at the root apex in tandem with upregulation of collagen I, integrin β5, and SPARC gene expression. PMID:17015623

IN-VIVO RADIATION DOSIMETRY USING PORTABLE L BAND EPR: ON-SITE MEASUREMENT OF VOLUNTEERS IN FUKUSHIMA PREFECTURE, JAPAN

PubMed Central

Miyake, Minoru; Nakai, Yasuhiro; Yamaguchi, Ichiro; Hirata, Hiroshi; Kunugita, Naoki; Williams, Benjamin B.; Swartz, Harold M.

2016-01-01

The aim of this study was to make direct measurements of the possible radiation-induced EPR signals in the teeth of volunteers who were residents in Fukushima within 80 km distance from the Fukushima Nuclear Power plant at the time of the disaster, and continued to live there for at least 3 month after the disaster. Thirty four volunteers were enrolled in this study. These measurements were made using a portable L-band EPR spectrometer, which was originally developed in the EPR Center at Dartmouth. All measurements were performed using surface loop resonators that have been specifically designed for the upper incisor teeth. Potentially these signals include not only radiation-induced signals induced by the incident but also background signals including those from prior radiation exposure from the environment and medical exposure. We demonstrated that it is feasible to transport the dosimeter to the measurement site and make valid measurements. The intensity of the signals that were obtained was not significantly above those seen in volunteers who had not had potential radiation exposures at Fukushima. PMID:27522046

Dentomaxillofacial characteristics of ectodermal dysplasia.

PubMed

Nakayama, Yumiko; Baba, Yoshiyuki; Tsuji, Michiko; Fukuoka, Hiroki; Ogawa, Takuya; Ohkuma, Mizue; Moriyama, Keiji

2015-02-01

The aim of this retrospective hospital-based study was to elucidate the dentomaxillofacial characteristics of ectodermal dysplasia. Six Japanese individuals (one male and five female; age range, 12.7-27.2 years) underwent comprehensive examinations, including history recording, cephalometric analysis, panoramic radiography, and analysis of dental models. All the subjects had two or more major manifestations for clinical diagnosis of ectodermal dysplasia (e.g., defects of hair, teeth, nails, and sweat glands). They presented hypodontia (mean number of missing teeth, 9.5; range, 5-14), especially in the premolar region, and enamel dysplasia. Five subjects had bilateral molar occlusion, whereas one subject had unilateral molar occlusion. The common skeletal features were small facial height, maxillary hypoplasia, counterclockwise rotation of the mandible, and mandibular protrusion. Interestingly, the maxillary first molars were located in higher positions and the upper anterior facial height was smaller than the Japanese norm. The results suggest that vertical and anteroposterior maxillary growth retardation, rather than lack of occlusal support due to hypodontia, leads to reduced anterior facial height in individuals with ectodermal dysplasia. © 2014 Japanese Teratology Society.

Orthodontic treatment in cherubism: an overview and a case report.

PubMed

Abela, Stefan; Cameron, Malcolm; Bister, Dirk

2014-11-01

Cherubism is a rare hereditary disease that frequently manifests as a painless enlargement of the mandible and/or maxilla. The disease usually progresses rapidly during the first and second decades of life but it is self-limiting and often regresses. Although few orthodontic case reports describing cherubic patients exist, the timing and extent of surgical intervention is controversial. This present paper aims to review the treatment literature and provide a case report of a patient who underwent orthodontic/surgical management. The patient presented with severe cherubism in her late teenage years; her main complaint was poor facial and dental appearance. Multiple teeth were missing and those present demonstrated significant preoperative root resorption. Treatment consisted of orthodontic alignment of the upper anterior teeth and a recontouring osteotomy. Confirmed by the patient, the combination approach led to a significant improvement in facial aesthetics and better self-esteem. Tooth movement through the osseous lesions was uneventful and no further root resoption was observed. Orthodontic treatment may be undertaken in those affected by Cherubism even with pre-existing idiopathic root resorption, but patients need to be appropriately informed and consented.

Use of a Novel ORMOCER as a Universal Direct Restorative Material.

PubMed

Hakim, Foroud; Vallée, Jessie

2018-01-01

Composite resin is considered the material of choice for direct restoration of teeth when esthetic outcome is a high priority. While material science improvements have mitigated many of the traditional liabilities related to composite resin restorations, shrinkage and related shrinkage stress still play a role in outcomes, placement techniques, and overall success. This case report demonstrates two restorative scenarios using an ORMOCER® composite material. The first features a female patient who, upon completion of preliminary orthodontic treatment, determined in consultation with the orthodontist that her central incisors would present more idealistic display and esthetics if they were lengthened by approximately 1.5 mm. The lengthening of the incisors was to precede the phase II refinement with clear aligners, which would aim to extrude the remaining anterior teeth to develop incisal balance and symmetry. The second case is that of a woman who presented with a newly symptomatic upper right second bicuspid with an existing nearly decade old, large MODL composite resin restoration. This article demonstrates the universal nature of the novel direct restorative material used, making it well-suited for both anterior and posterior applications.

Digital reconstruction of the mandible of an adult Lesothosaurus diagnosticus with insight into the tooth replacement process and diet

PubMed Central

Knoll, Fabien; Bordy, Emese M.; de Kock, Michiel O.; Redelstorff, Ragna

2017-01-01

Fragmentary caudal ends of the left and right mandible assigned to Lesothosaurus diagnosticus, an early ornithischian, was recently discovered in the continental red bed succession of the upper Elliot Formation (Lower Jurassic) at Likhoele Mountain (Mafeteng District) in Lesotho. Using micro-CT scanning, this mandible could be digitally reconstructed in 3D. The replacement teeth within the better preserved (left) dentary were visualised. The computed tomography dataset suggests asynchronous tooth replacement in an individual identified as an adult on the basis of bone histology. Clear evidence for systematic wear facets created by attrition is lacking. The two most heavily worn teeth are only apically truncated. Our observations of this specimen as well as others do not support the high level of dental wear expected from the semi-arid palaeoenvironment in which Lesothosaurus diagnosticus lived. Accordingly, a facultative omnivorous lifestyle, where seasonality determined the availability, quality, and abundance of food is suggested. This would have allowed for adaptability to episodes of increased environmental stress. PMID:28265518

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

Ross, R.J.; Kurihara, Y.

The influence of Hurricane Gloria (1985) on the environment is investigated by comparing hurricane model integrations either including or excluding the hurricane in the initial condition. Results for three cases of Gloria at different states of development are presented. The hurricane`s cumulative influence is identified as the differences between the hurricane and nonhurricane integrations. Throughout the integration period, area with sea level pressure differences exceeding 1 hPa in magnitude expanded in each of the three cases and was centered at the hurricane location. The influence radius of the storm, which was determined from the sea level pressure difference field, eventuallymore » reached approximately 1500 km in all cases. Comparisons of the sea level pressure differences among the three cases showed that the expansion rate differed for each case but was only weakly related to the intensity or intensity change of the particular storm. The comparisons of the wind and temperature fields from the hurricane and nonhurricane integrations indicated that the areal extent of the hurricane`s influence was much larger at the upper layer than at the lower layer. A stronger anticyclonic circulation and relatively warmer temperatures developed at the upper layer in the hurricane integration compared to the nonhurricane fields. These upper-layer changes extended over an area comparable in size with the sea level pressure differences. At the lower layer, the differences between the hurricane and nonhurricane wind and temperature fields showed the impact of hurricane on the passage of a cold front over the eastern United States. Apparently, the hurricane`s cyclonic circulation at the lower layer affected the movement of the front approaching from the west.« less

Rapid urease test (RUT) for evaluation of urease activity in oral bacteria in vitro and in supragingival dental plaque ex vivo.

PubMed

Dahlén, Gunnar; Hassan, Haidar; Blomqvist, Susanne; Carlén, Anette

2018-05-18

Urease is an enzyme produced by plaque bacteria hydrolysing urea from saliva and gingival exudate into ammonia in order to regulate the pH in the dental biofilm. The aim of this study was to assess the urease activity among oral bacterial species by using the rapid urease test (RUT) in a micro-plate format and to examine whether this test could be used for measuring the urease activity in site-specific supragingival dental plaque samples ex vivo. The RUT test is based on 2% urea in peptone broth solution and with phenol red at pH 6.0. Oral bacterial species were tested for their urease activity using 100 μl of RUT test solution in the well of a micro-plate to which a 1 μl amount of cells collected after growth on blood agar plates or in broth, were added. The color change was determined after 15, 30 min, and 1 and 2 h. The reaction was graded in a 4-graded scale (none, weak, medium, strong). Ex vivo evaluation of dental plaque urease activity was tested in supragingival 1 μl plaque samples collected from 4 interproximal sites of front teeth and molars in 18 adult volunteers. The color reaction was read after 1 h in room temperature and scored as in the in vitro test. The strongest activity was registered for Staphylococcus epidermidis, Helicobacter pylori, Campylobacter ureolyticus and some strains of Haemophilus parainfluenzae, while known ureolytic species such as Streptococcus salivarius and Actinomyces naeslundii showed a weaker, variable and strain-dependent activity. Temperature had minor influence on the RUT reaction. The interproximal supragingival dental plaque between the lower central incisors (site 31/41) showed significantly higher scores compared to between the upper central incisors (site 11/21), between the upper left first molar and second premolar (site 26/25) and between the lower right second premolar and molar (site 45/46). The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease activity in bacterial strains in vitro and as a chair-side method for testing urease activity in site-specific supragingival plaque samples ex vivo.

Tooth wear and dentoalveolar remodeling are key factors of morphological variation in the Dmanisi mandibles

PubMed Central

Margvelashvili, Ann; Zollikofer, Christoph P. E.; Lordkipanidze, David; Peltomäki, Timo; Ponce de León, Marcia S.

2013-01-01

The Plio-Pleistocene hominin sample from Dmanisi (Georgia), dated to 1.77 million years ago, is unique in offering detailed insights into patterns of morphological variation within a paleodeme of early Homo. Cranial and dentoalveolar morphologies exhibit a high degree of diversity, but the causes of variation are still relatively unexplored. Here we show that wear-related dentoalveolar remodeling is one of the principal mechanisms causing mandibular shape variation in fossil Homo and in modern human hunter–gatherer populations. We identify a consistent pattern of mandibular morphological alteration, suggesting that dental wear and compensatory remodeling mechanisms remained fairly constant throughout the evolution of the genus Homo. With increasing occlusal and interproximal tooth wear, the teeth continue to erupt, the posterior dentition tends to drift in a mesial direction, and the front teeth become more upright. The resulting changes in dentognathic size and shape are substantial and need to be taken into account in comparative taxonomic analyses of isolated hominin mandibles. Our data further show that excessive tooth wear eventually leads to a breakdown of the normal remodeling mechanisms, resulting in dentognathic pathologies, tooth loss, and loss of masticatory function. Complete breakdown of dentognathic homeostasis, however, is unlikely to have limited the life span of early Homo because this effect was likely mediated by the preparation of soft foods. PMID:24101504

Rover Soil Experiments Near Yogi

NASA Technical Reports Server (NTRS)

1997-01-01

Sojourner, while on its way to the rock Yogi, performed several soil mechanics experiments. Piles of loose material churned up from the experiment are seen in front of and behind the Rover. The rock Pop-Tart is visible near the front right rover wheel. Yogi is at upper right. The image was taken by the Imager for Mars Pathfinder.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Boulder Creek: A stream ecosystem in an urban landscape

USGS Publications Warehouse

Verplanck, Philip L.; Murphy, Sheila F.; Birkeland, Peter W.; Pitlick,; Barber, Larry B.; Schmidt, Travis S.; Raynolds, Robert G.H.

2008-01-01

The Boulder Creek Watershed, within the Front Range region of Colorado, is typical of many western watersheds because it is composed of a high-gradient upper reach mostly fed by snowmelt, a substantial change in gradient at the range front, and an urban corridor within the lower gradient section. A stream ecosystem within an urban landscape not only can provide water for municipal, industrial, and agricultural needs, but also can be utilized for recreation, esthetic enjoyment, and wastewater disposal. The purpose of this 26 km bicycle field trip is to explore the hydrology and geochemistry of Boulder and South Boulder Creeks and to discuss topics including flood frequency and hazards, aqueous geochemistry of the watershed, and potential impacts of invasive species and emerging contaminants on stream ecology.

Thoughts on Multi-sphere Study in the Indo-Pacific Convergent Zone

NASA Astrophysics Data System (ADS)

Wang, F.

2016-12-01

Interactions of the ocean with other components of the earth system, such as atmosphere, lithosphere, and biosphere are the front and hotspot of the ocean and earth sciences. In the Indonesian Archipelago and adjacent western Pacific and eastern Indian Oceans, both the upper oceanic circulation and lower atmospheric circulation convergent and consequently enhance the fresh water and heat fluxes, affecting the East Asian and global climate. This region is considered as the world's center of marine bio-diversity and sediment discharge, as well as the collision center of the Eurasian, Indian and Pacific plates. Why and how the energy and material of multiple spheres convergent toward the region are important scientific issues on the front of earth system science and marine sciences, and need to be investigated through international cooperation.

The Effect of Driver Age On The Incidence And Severity Of Upper Extremity Injuries Due To Second Generation Front Air Bag Deployment

PubMed Central

Marshall, Rafael; Hunting, Katherine; McKay, Mary Pat

2010-01-01

This study used NHTSA NASS/CDS data to examine whether advancing age was associated with a higher incidence and severity of front airbag-related upper extremity injury (UEI). Using a retrospective cohort design we analyzed weighted data from 1998–2007 for. The study population consisted of lap/shoulder belted people over 16 years of age who were driving passenger vehicles with model years 1998–2003 and were involved in a frontal crash where their front airbag deployed. Drivers who were ejected, involved in a vehicle rollover, or accompanied by a passenger sitting directly behind them were omitted. The exposure variable was age and the outcome variables were UEI incidence and severity. Associations were adjusted for gender, seat track position, vehicle type, vehicle weight, intrusion, and delta-v. Logistic regressions were performed using SAS survey procedures to account for the complex survey design. Overall, 42% of drivers sustained an UEI. Advancing age was associated with a higher incidence (p<0. 0001) and severity (p<0. 0001) of UEI. Nineteen percent of drivers sustained an UEI related to the airbag. No significant differences in the incidence or severity of airbag-related UEI were found between young drivers and older driver age groups. The degree of severity due to airbag-related UEI was generally minor. The majority of airbag-related UEI appeared to shift slightly from abrasions to contusions with aging. These results indicate that UEI due to depowered airbag deployment is common but not disproportionately high among older drivers, and injury severity is generally minor across all age groups. PMID:21050604

The summer hydrographic structure of the Hanna Shoal region on the northeastern Chukchi Sea shelf: 2011-2013

NASA Astrophysics Data System (ADS)

Weingartner, Thomas; Fang, Ying-Chih; Winsor, Peter; Dobbins, Elizabeth; Potter, Rachel; Statscewich, Hank; Mudge, Todd; Irving, Brita; Sousa, Leandra; Borg, Keath

2017-10-01

We used shipboard and towed CTD, current meter, and satellite-tracked drifter data to examine the hydrographic structure in the northeastern Chukchi Sea in August-September of 2011, 2012, and 2013. In all years the densest winter water was around and east of Hanna Shoal. In 2012 and 2013, a 15 m deep layer of cold, dilute meltwater overlaid the dense water north of the shelf region between 71.2 and 71.5°N. A front extends from the southwest side of Hanna Shoal toward the head of Barrow Canyon, separated meltwaters from warmer, saltier Bering Sea Summer Waters to the south. Stratification was stronger and the surface density variances in the meso- and sub-mesoscale range were higher north of the front than to the south. No meltwater or surface fronts were present in 2011 due to a very early ice retreat. Differences in summer ice cover may be due to differences in the amount of grounded ice atop Hanna Shoal associated with the previous winter's regional ice drift. Along the north side of Hanna Shoal the model-predicted clockwise barotropic flow carrying waters from the western side of the Shoal appears to converge with a counterclockwise, baroclinic flow on the northeast side. The baroclinic tendency is confined to the upper 30 m and can include waters transported from the shelfbreak. The inferred zonal convergence implies that north of the Shoal: a) near-surface waters are a mixture of waters from the western and eastern Chukchi Sea and b) the cross-isobath pressure gradient collapses thereby facilitating leakage of upper layer waters northward across the shelf.

Drake Passage-Antarctic Peninsula Ecosystem Research: Spring and Fall Zooplankton and Seabird Assemblages

NASA Astrophysics Data System (ADS)

Loeb, V. J.; Chereskin, T. K.; Santora, J. A.

2016-02-01

Acoustic Doppler Current Profiler (ADCP) records from multiple "L.M. Gould" supply transits of Drake Passage from 1999 to present demonstrate spatial and temporal (diel, seasonal, annual and longer term) variability in acoustics backscattering. Acoustics backscattering strength in the upper water column corresponds to zooplankton and nekton biomass that relates to seabird and mammal distribution and abundance. Recent results indicate that interannual variability in backscattering strength is correlated to climate indices. The interpretation of these ecological changes is severely limited because the sound scatterers previously had not been identified and linkages to upper trophic level predators are unknown. Net-tows, depth-referenced underwater videography and seabird/mammal visual surveys during spring 2014 and fall 2015 transits provided information on the taxonomic-size composition, distribution, aggregation and behavioral patterns of dominant ADCP backscattering organisms and relate these to higher level predator populations. The distribution and composition of zooplankton species and seabird assemblages conformed to four biogeographic regions. Areas of elevated secondary productivity coincided with increased ADCP target strength with highest concentrations off Patagonia and Antarctic Peninsula and secondary peaks around the Polar Front. Small sized zooplankton taxa dominated north of the Polar Front while larger taxa dominated to the south. Regionally important prey items likely are: copepods, amphipods, small euphausiids and fish (Patagonia); copepods, myctophids, shelled pteropods and squid (Polar Front); large euphausiids (Antarctic Peninsula). This study demonstrates that biological observations during "L.M. Gould" supply transits greatly augment the value of routinely collected ADCP and XBT data and provide basic information relevant to the impacts of climate change in this rapidly warming portion of the Southern Ocean

Geochemical Relationships between Middle- to Upper-Crustal Exposures of the Alisitos Oceanic Arc (Baja California, Mexico): An Outstanding Field Analog to Active Extensional Oceanic Arcs

NASA Astrophysics Data System (ADS)

Morris, R.; DeBari, S. M.; Busby, C.; Medynski, S.

2016-12-01

The southern volcano-bounded basin of the Rosario segment of the Cretaceous Alisitos oceanic arc provides outstanding 3-D exposures of an extensional arc, where crustal generation processes are recorded in the upper-crustal volcanic units and underlying middle-crustal plutonic rocks. Geochemical linkages between exposed crustal levels provide an analog for extensional arc systems such as the Izu-Bonin-Mariana (IBM) Arc. Upper-crustal units comprise a 3-5 km thick volcanic-volcaniclastic stratigraphy with hypabyssal intrusions. Deep-seated plutonic rocks intrude these units over a transition of <500m, where rafted volcanic blocks and evidence of magma mingling are exposed. Thermobarometry suggests <6 km emplacement depths. Compositional ranges (basalt to rhyolite) and mineral assemblages are similar in both middle-crustal and upper-crustal units, with striking compositional overlap. The most mafic compositions occur in upper-crustal hypabyssal units, and as amphibole cumulates in the plutonic rocks ( 51% SiO2). The most felsic compositions occur in welded ignimbrites and a tonalite pluton ( 71% SiO2). All units are low K with flat REE patterns, and show LILE enrichment and HFSE depletion. Trace element ratios show limited variation throughout the crustal section. Zr/Y and Nb/Y ratios are similar to the Izu active ( 3 Ma to present) zone of extension immediately behind the arc front, suggesting comparable mantle melt % during extension. Th/Zr ratios are more enriched in Alisitos compared to Izu, suggesting greater subducted sediment input. The Alisitos crustal section shows a limited range in ɛNd (5.7-7.1), but a wider range in 87Sr/86Sr (0.7035-0.7055) and 206Pb/204Pb (18.12-19.12); the latter is likely alteration effects. Arc magmas were derived from a subduction-modified MORB mantle source, less depleted than Izu arc front and less enriched than the rear arc, but is a good match with the zone of extension that lies between. Differentiation occurred in a closed system (i.e., fractional crystallization/self-melting with back mixing), producing the entire crustal section in <3 Ma.

A cross-sectional survey to assess the effect of socioeconomic status on the oral hygiene habits

PubMed Central

Oberoi, Sukhvinder Singh; Sharma, Gaurav; Oberoi, Avneet

2016-01-01

Background: It is widely accepted that there are socioeconomic inequalities in oral health. A socioeconomic gradient is found in a range of clinical and self-reported oral health outcomes. Aim: The present study was conducted to assess the differences in oral hygiene practices among patients from different socioeconomic status (SES) visiting the Outpatient Department of the Sudha Rustagi College of Dental Sciences. Materials and Methods: A cross-sectional survey was conducted from June to October 2014 to assess the effect of SES on the oral hygiene habits. The questionnaire included the questions related to the demographic profile and assessment of the oral hygiene habits of the study population. Results: Toothbrush and toothpaste were being used significantly (P < 0.05) more by lower middle class (84.4%) and upper middle class (100.0%). A significantly higher frequency of cleaning teeth (twice a day) was reported among the lower middle class (17.2%) and upper middle class (21.5%). The majority (34.3%) of the study population changed their toothbrush once in 3 months. The cleaning of tongue was reported by patients belonging to the upper middle (62.0%), lower middle (52.1%), and upper lower class (30.0%). The use of tongue cleaner was reported to be significantly (P < 0.05) more among upper middle (10.1%) class patients. A significantly higher number of patients from the lower class (81.3%) never visited a dentist. Conclusion: The oral hygiene practices of the patients from upper and lower middle class was found to be satisfactory whereas it was poor among patients belonging to lower and upper lower class. PMID:29242690

The Prehistory of the Proposed Clayton Lake Area, Southeast Oklahoma. Phase I Investigations.

DTIC Science & Technology

1979-01-01

TEETH (01-00) 01-01A ( 1 ’• ..:! 1 Table 94 8. Continued SHELL (02-00) Molluscs (02-01) 02-01A Gastropods (02-02) 02-02A Floral (09...02A N=l A fossilized gastropod was recovered from the upper 20 cm of the deposit. Historic Debris (07) GLASS (01-00) 07-01-01A N=l This clear...02-01A N=l This freshwater mussel shell fragment (.01 g) is unburned and occurs at a depth of 20-30 cm. Gastropods (08-02-02) 08-02-02A N=15

About Kids' Teeth

MedlinePlus

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

Fire, Lava Flows, and Human Evolution

NASA Astrophysics Data System (ADS)

Medler, M. J.

2015-12-01

Richard Wrangham and others argue that cooked food has been obligate for our ancestors since the time of Homo erectus. This hypothesis provides a particularly compelling explanation for the smaller mouths and teeth, shorter intestines, and larger brains that separate us from other hominins. However, natural ignitions are infrequent and it is unclear how earlier hominins may have adapted to cooked food and fire before they developed the necessary intelligence to make or control fire. To address this conundrum, we present cartographical evidence that the massive and long lasting lava flows in the African Rift could have provided our ancestors with episodic access to heat and fire as the front edges of these flows formed ephemeral pockets of heat and ignition and other geothermal features. For the last several million years major lava flows have been infilling the African Rift. After major eruptions there were likely more slowly advancing lava fronts creating small areas with very specific adaptive pressures and opportunities for small isolated groups of hominins. Some of these episodes of isolation may have extended for millennia allowing these groups of early hominins to develop the adaptations Wrangham links to fire and cooked food. To examine the potential veracity of this proposal, we developed a series of maps that overlay the locations of prominent hominin dig sites with contemporaneous lava flows. These maps indicate that many important developments in hominin evolution were occurring in rough spatial and temporal proximity to active lava flows. These maps indicate it is worth considering that over the last several million years small isolated populations of hominins may have experienced unique adaptive conditions while living near the front edges of these slowly advancing lava flows.

ROSS: The Remotely-Operated Surface Sampler - A MediumEndurance, Precision-Navigated Platform Optimized for Uncontaminated Measurement of Upper-Ocean Velocity, Density and Turbulence

DTIC Science & Technology

2015-09-30

ocean  surface.   It  is ideal for studying fronts, river plumes, near-­‐surface  phenomena like ice-­‐ melt  or rain   puddles,  air...regions  too  dangerous  for manned craft (like near glacier faces),  and for interpreting  the  undersea structure  of satellite

Holocene Millennial-scale Surface and Bottom Water Variability, Feni Drift, NE Atlantic Ocean: Foraminiferal Assemblages

NASA Astrophysics Data System (ADS)

Lassen, S. J.; Richter, T. O.; de Stigter, H. C.; van Weering, T. C. E.; de Haas, H.

A high-resolution sediment core from Feni Drift (ENAM9606, 56N 14W, 2543 m wa- ter depth) was investigated for planktonic and benthic foraminiferal assemblages dur- ing the last 12,000 years. During the Preboreal, peak abundances of T.quinqueloba indicate the passage of the Arctic front over the core site. Holocene planktonic foraminiferal assemblages indicate a gradual warming trend of surface water masses punctuated by a major cooling (8,200ky event s.l.), and possibly a slight cooling dur- ing the last 3,000 years. The interval from 10 to 5kyrs shows higher and fluctuating abundances of T.quinqueloba and G.bulloides, which suggest proximity of the subarc- tic front and enhanced spring blooms compared to the upper Holocene. Abundance peaks of N.pachyderma(s) and/or T.quinqueloba indicate a series of millennial-scale cooling events during the entire Holocene, which can be correlated to similar episodes previously described from other locations in the North Atlantic and Norwegian- Greenland Sea. Benthic foraminiferal assemblages indicate a gradual transition from seasonal, spring-bloom related food supply in the Lower Holocene (dominance of the phytodetritus species E.exigua) to possibly lower, but more sustained food supply in the Upper Holocene (dominance of C.obtusa and C.laevigata).

Advanced Optics for a Full Quasi-Optical Front Steering ECRH Upper Launcher for ITER

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

Moro, A.; Alessi, E.; Bruschi, A.

2009-11-26

A full quasi-optical setup for the internal optics of the Front Steering Electron Cyclotron Resonance Heating (ECRH) Upper Launcher for ITER was designed, proving to be feasible and favorable in terms of additional flexibility and cost reduction with respect to the former design. This full quasi-optical solution foresees the replacement of the mitre-bends in the final section of the launcher with dedicated free-space mirrors to realize the last changes of directions in the launcher. A description of the launcher is given and its advantages presented. The parameters of the expected output beams as well as preliminary evaluations of truncation effectsmore » with the physical optics GRASP code are shown. Moreover, a study of mitre-bends replacement with single mirrors for multiple beams is described. In principle it could allow the beams to be larger at the mirror locations (with a further decrease of the peak power density due to partial overlapping) and has the additional advantage to get a larger opening with compressed beams to avoid conflicts with side-walls port. Constraints on the setup, arising both from the resulting beam characteristics in the space of free parameters and from mechanical requirements are taken into account in the analysis.« less

The Physics Performance Of The Front Steering Launcher For The ITER ECRH Upper Port

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

Henderson, M.; Chavan, R.; Nikkola, P.

2005-09-26

The capability of any given e.m.-wave plasma heating system to be utilized for physics applications depends strongly on the technical properties of the launching antenna (or launcher). An effective ECH launcher must project a small mm-wave beam spot size far into the plasma and 'steer' the beam across a large fraction of the plasma cross section (along the resonance surface). Thus the choice in the launcher concept and design may either severely limit or enhance the capability of a heating system to be effectively applied for physics applications, such as sawtooth stabilization, control of the Neoclassical Tearing Mode (NTM), Edgemore » Localized Mode (ELM) control, etc. Presently, two antenna concepts are under consideration for the ITER upper port ECH launcher: front steering (FS) and remote steering (RS) launchers. The RS launcher has the technical advantage of easier maintenance access to the steering mirror, which is isolated from the torus vacuum. The FS launcher places the steering mirror near the plasma increasing the technical challenges, but significantly enhancing the focusing and steering capabilities of the launcher, offering a threefold increase in NTM stabilization efficiency over the RS launcher as well as the potential for application to other critical physics issues such as ELM or sawtooth control.« less

Investigations of greenhouse gas variability across frontal structures in the lower troposphere during winter: Findings from the ACT - America Winter 2017 Campaign

NASA Astrophysics Data System (ADS)

Davis, K. J.; Pal, S.; Baier, B.; Browell, E. V.; Choi, Y.; DiGangi, J. P.; Dobler, J. T.; Erxleben, W. H.; Feng, S.; Gaudet, B. J.; Kooi, S. A.; Lauvaux, T.; Lin, B.; McGill, M. J.; Hoffman, K.; Obland, M. D.; Pauly, R.; Sweeney, C.

2017-12-01

Synoptic scale weather events like cold front passages play an important role in distributing greenhouse gases (GHG, e.g., CO2, CH4) in the atmosphere. However, our knowledge and observational evidence on the GHG structures across frontal boundaries are limited. The second airborne field campaign of the Atmospheric Carbon and Transport - America (ACT-America) project in winter (January 30 - March 10 2017) documented gradients in GHGs across 9 frontal systems in three regions of the US, namely, Mid-Atlantic, Upper Mid-West, and South. High-resolution remote and in-situ airborne observations were collected with two aircraft: NASA C-130 and B-200. Using both active remote sensing and in-situ observations, we will discuss the magnitude of GHG frontal gradients in the atmospheric boundary layer (ABL) and free troposphere (FT) and how they vary among cases during winter. Three mechanisms for creating these gradients will be investigated: 1) local ecosystem or anthropogenic GHG sources; 2) horizontal transport of planetary scale, seasonal gradients; and 3) vertical mixing, especially associated with clouds and boundary layer depth depths. Preliminary analyses indicate higher front-related CO2 gradients in the boundary layer compared to the upper and lower FT as well as larger case-to-case variability in front-related CO2 gradients in the ABL compared to the FT. GHG gradients across fronts were smaller than in the summer, but still present. Tentatively, the signs of the CO2 gradients (vertical and frontal) in winter appear to have switched compared to the summer with higher CO2 concentrations in the cold sector of the frontal region than in the warm sector during the wintertime, but the CH4 gradients were similar in the two seasons. Using observations and simulations for both summer and winter, we will build toward a conceptual framework of the CO2 and CH4 gradients across frontal boundaries and provide insights into how boundary layer-regimes and synoptic-scale transport redistributes CO2 and CH4 across the midlatitudes.

Embryonic development of Python sebae - II: Craniofacial microscopic anatomy, cell proliferation and apoptosis.

PubMed

Buchtová, Marcela; Boughner, Julia C; Fu, Katherine; Diewert, Virginia M; Richman, Joy M

2007-01-01

This study explores the microscopic craniofacial morphogenesis of the oviparous African rock python (Python sebae) spanning the first two-thirds of the post-oviposition period. At the time of laying, the python embryo consists of largely undifferentiated mesenchyme and epithelium with the exception of the cranial base and trabeculae cranii, which are undergoing chondrogenesis. The facial prominences are well defined and are at a late stage, close to the time when lip fusion begins. Later (11-12d), specializations in the epithelia begin to differentiate (vomeronasal and olfactory epithelia, teeth). Dental development in snakes is different from that of mammals in several aspects including an extended dental lamina with the capacity to form 4 sets of generational teeth. In addition, the ophidian olfactory system is very different from the mammalian. There is a large vomeronasal organ, a nasal cavity proper and an extraconchal space. All of these areas are lined with a greatly expanded olfactory epithelium. Intramembranous bone differentiation is taking place at stage 3 with some bones already ossifying whereas most are only represented as mesenchymal condensations. In addition to routine histological staining, PCNA immunohistochemistry reveals relatively higher levels of proliferation in the extending dental laminae, in osseous mesenchymal condensations and in the olfactory epithelia. Areas undergoing apoptosis were noted in the enamel organs of the teeth and osseous mesenchymal condensations. We propose that localized apoptosis helps to divide a single condensation into multiple ossification centres and this is a mechanism whereby novel morphology can be selected in response to evolutionary pressures. Several additional differences in head morphology between snakes and other amniotes were noted including a palatal groove separating the inner and outer row of teeth in the upper jaw, a tracheal opening within the tongue and a pharyngeal adhesion that closes off the pharynx from the oral cavity between stages 1 and 4. Our studies on these and other differences in the python will provide valuable insights into in developmental, molecular and evolutionary mechanisms of patterning.

A comparative study on sealing ability of mineral trioxide aggregate, calcium enriched cement and bone cement in furcal perforations.

PubMed

Nazari Moghadam, K; Aghili, H; Rashed Mohassel, A; Zahedpasha, S; Moghadamnia, A A

2014-06-01

The aim of this study was to compare the bacterial leakage of mineral trioxide aggregate (MTA), calcium enriched cement (CEM), and bone cement (BC) as repair materials in furcal perforations. The pulp chambers of 57 human mandibular molar teeth were accessed and the root canal orifices were located. The roots were horizontally sectioned in the middle third. Composite resin was used to fill the root canal orifices and the apical end of the roots. The 1 mm furcation perforations were performed in the center of the pulp chamber floor, using diamond fissure burs. Fifty one teeth were divided into 3 groups. Six teeth were used as controls. Perforation defects were repaired with either MTA, CEM, or BC. A bacterial leakage model utilizing phenol red with 3% lactose broth was used for evaluation. The upper pulp chambers were subsequently filled with 5μL bacterial suspension containing Enterococcus faecalis. Then the top of the assembly was covered with aluminum foil to avoid unintentional contamination. The entire apparatus was incubated at 37°C, and bacterial leakage was evaluated daily by checking the turbidity in the culture medium of the lower part of the chamber. The bacterial inoculation was renewed every day, for 30 days. Leakage was noted when color conversion of the culture media was observed and was statistically analyzed using the Chi-square test with significance set at P< 0.05. Sixteen (94%) of the 17 samples of the MTA group, thirteen (81%) of the 17 samples of the CEM group and sixteen (94%) of the 17 samples in BC group were fully contaminated at 30 days. There was no statistically significant difference between the three study groups (P>0.05). According to the present study, in teeth with furcation perforations, the coronal seal produced by MTA preparations was equally to that produced by CEM cement and Bone cement.