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Crenulated occlusal surfaces have previously been described on maxillary and mandibular molars; however, the occurrence of crenulations on premolars is only anecdotally supported. This study applies a modified version of a recordation scale developed for molar crenulations to record the frequency of crenulated premolars on the maxillary and mandibular premolars of modern individuals from a variety of populations: African, African American, Asian, Australian, European American, Latino, and Malay (n = 1238). Crenulations on the molars of the same individuals were also recorded to assess the relationship between occurrences on premolars and molars. Observations were compiled into frequency tables and analyzed using chi-square tests and correspondence analysis; relationships among teeth were quantified with polychoric correlation coefficients. Although crenulated premolars are observed rarely overall, the frequency of occurrence is significantly associated with group membership. Crenulated premolars occur most frequently in African, African American, and Australian samples and are observed least often among European American and Malay samples. Additionally, there is a strong relationship between third and fourth premolars, particularly within a jaw, and between fourth premolars and the molars in the same jaw. Interestingly, crenulations in premolars are most strongly associated with Grade 2 crenulations on molars. The observed differences between populations, and the associations between crenulated premolars and molars are evaluated with respect to function, tooth size, and dental development. Based on the results presented here, we recommend the addition of premolar crenulations to existing dental morphological traits used to study human population variation.

This cross-sectional study compared tooth and dental arch dimensions of individuals with Osteogenesis imperfecta (OI) and healthy controls.The 37 OI patients and 37 controls were aged 10 to 74 years. Mesio-distal tooth size, dental arch dimensions, and palatal height were measured from dental models. The differences between the patient and control groups were analysed statistically with a t-test, chi-square test, and Mann-Whitney U test.The average mesio-distal tooth size of individuals with OI was smaller by 0.1 to 0.8 mm, corresponding to 1.4 to 7.3% of the size of the tooth. The patients and controls showed similar anterior-posterior lengths of maxillary and mandibular arches. The OI patient group exhibited increasingly wider maxillary dental arches posterior to the canines and a shallow palate.Reduced tooth size is a developmental feature of OI and a shallow palate a characteristic possibly associated with previously documented imparity of vertical jaw development. Observed posterior widening of the dental arches may follow from altered tongue position. Smaller tooth size can be favourable from orthodontic point of view in alleviating crowding, but it might further predispose to fracturing of teeth which is a considerable risk associated with dentine abnormality. The shallow jawbones may initiate development of posterior open bite, rare in general population but relatively often encountered in OI.

Objective:To evaluate if genetic polymorphisms in the oestrogen receptor 1 ( ESR1) and oestrogen receptor 2 ( ESR2) genes encoded for oestrogen receptors alpha (ERα) and beta (ERβ) are involved in permanent tooth size.Design:Cross-sectional study.Setting:Orthodontic Clinic at School of Dentistry of Ribeirão Preto, University of São Paulo.Participants:A total of 108 orthodontic patients.Materials and Methods:Pre-treatment orthodontic records were evaluated. Dental casts were used to determine the maximum crown measurements of fully erupted permanent teeth in the mesiodistal dimensions. Second and third molars were not included in the analysis. Genomic DNA samples were used for the genotyping of four genetic polymorphisms: ESR1 (rs9340799 and rs2234693) and ESR2 (rs1256049 and rs4986938). The associations between tooth size and sex were evaluated using t test. The associations between tooth size and genotype were analysed with linear regression and adjusted by sex at an alpha of P⩽0.05.Results:Female patients presented smaller tooth size than male patients. A statistically significant difference was observed in almost all teeth ( PConclusion:This study provides evidence that genetic polymorphisms in ESR1 and ESR2 could be associated with tooth size in permanent teeth.

ObjectivesMalocclusion features differ across various populations and ethnicities. At this time, no data are available regarding the dentofacial differences between Syrian and European adolescents with Class II division 1 malocclusion, which is one of the most frequently treated pathologies in orthodontic practice. The present combined cephalometric and tooth-size study aimed to compare the dentoskeletal and tooth-size characteristics of Syrian and Hungarian adolescents with Class II division 1 malocclusion.ResultsClass II division 1 malocclusion in Hungarian adolescents was a sagittal discrepancy, while in Syrian adolescents, it was a result of excessive vertical development. Syrian adolescents had a significantly excessive vertical development when compared with Hungarian adolescents, regardless of sex(p 0.01). Hungarian boys had significantly more protruded maxillae(p 0.001)and less retruded mandibles (p 0.01)when compared with Syrian boys, while Hungarian girls had significantly shorter mandibles relative to those of Syrian girls (p 0.01). Syrian girls had significantly more protrusive lower incisors (p 0.001), accompanied by significantly larger anterior tooth-size ratios when compared to Hungarian girls (p 0.001). In conclusion, these findings underscore the importance of considering ethnic differences during orthodontic diagnosis and may have implications for optimizing orthodontic treatments in Syrian and Hungarian adolescents with Class II division 1 malocclusion.

Objective This study was performed to investigate the process of ectopic tooth formation. Methods A patient with an ectopic tooth was followed for 6 years. The tooth size and mineralization were evaluated by paranasal sinus computed tomography every 3 years. Results The ectopic tooth was present in the nasal crest of the maxilla and did not change significantly during the 6-year follow-up period. However, the patient developed a new ectopic tooth in the maxillary sinus (ETm). This tooth, located in the posterior wall of the left maxillary sinus, initially appeared as a small region of soft tissue on computed tomography. After 3 years, the area of mixed density had significantly increased, and some of it had significantly mineralized to form an ETm. After 6 years, the ETm had further mineralized and enlarged in situ. The width between the left and right sides of the ETm in 2018 (9.08 ± 2.09 mm) was significantly larger than that in 2015 (7.51 ± 2.18 mm), indicating that ETm formation is a gradual process of mineralization. Conclusion Ectopic teeth can gradually form by in situ mineralization after adolescence, suggesting that ectopic teeth are genetically regulated and result from a programmed formation process occurring at a specific time point.

Boston University (BU) approach is a method for early prediction of unerupted permanent mandibular teeth widths based on the mesiodistal widths (MDWs) of primary mandibular canines and first molars. The present study was conducted to test the validity of BU approach by comparing it with Tanaka-Johnston (T/J) approach in the contemporary population.The aim of the study was to determine the applicability of BU approach for prediction of the MDWs of canines and premolars in the primary schoolchildren of rural Bengaluru.The study was conducted in 100 healthy schoolchildren of rural Bengaluru aged between 7 and 11 years. The MDWs of canines and premolars were predicted using both T/J and the considered BU approaches for all the children and were compared.The correlation coefficient showed a statistically significant correlation between the predicted tooth size from the two predicted methods in the upper and lower arches (P0.001), with Pearson's correlation coefficient showing the very strong positive relationship (r = 0.7). Significant differences were seen between the mean predicted width of canines and premolars by both the approaches (P0.001).In spite of the limitations, we recommend the use of BU approach to predict arch length-tooth material discrepancy at an early age and to get at least an approximate estimation of the required space. We also advocate the necessity of further research on this approach prospectively.

Background: In mixed dentition analysis, estimation of the mesiodistal width of unerupted permanent canines and premolars is essential for successful diagnosis and treatment planning. The present study aimed to develop a simple linear equation to predict permanent tooth sizes from mixed dentition analysis for Taiwanese people. Methods: The sample comprised 200 dental casts, derived from Taiwanese patients (100 males and 100 females, age, 12–35 years). Mesial distal tooth widths were measured in dental casts with a digital caliper. A student’s t-test was conducted to detect tooth size correlations with gender-specific differences, as well as intra-arch counterparts. Standard linear regression was conducted to develop a simple equation representing predictions of canine-premolar relationships. Results: All teeth were not significantly different between the left and right sides, regardless of gender and upper or lower arches. In terms of types of teeth, males had larger tooth dimensions in both arches than females. New regression equations for estimating the dimensions of the unerupted canines and premolars in the Taiwanese population were developed. Conclusions: Using a sample of Taiwanese people, new models derived for females and males separately were developed, which should provide highly accurate predictions for unerupted canines and premolars in the Taiwanese population.

Aim The contemporary article aims to review and compare various literatures concerning different conclusions regarding the correlation between tooth size discrepancy (TSD) and Angle's malocclusion groups. Background Acquiring the ideal occlusion plays one of the major roles while designing the treatment plan for an orthodontic patient, any alterations in the individual tooth sizes are called TSD and will hinder this prime requirement. By determining the correct tooth size ratio, it further helps in acquiring the accurate interdigitation, balanced occlusion, and also predicting the orthodontic treatment results. Various investigations were carried out to know the correlation between tooth size discrepancies and different malocclusion groups, of which, a few reported a statistically significant difference whereas others reported no significant difference. Review results A computerized database quest was operated utilizing the Medline database (Pubmed/Medline) for original research and review articles. Publications between 1946 and 2018 were included. Four hundred twenty-one articles were recovered from database search and, among them, 66 articles were selected to review the full-article. Conclusion Although a comparison was done between the tooth-size ratios and malocclusion groups (classes I, II, and III), many investigators noted no significant difference but there is an inadequacy in the data particularly related to subgroups of Angle's classification of malocclusion among these investigations; therefore, further studies are required to interpret this correlation. Clinical significance As there is high incidence of tooth size discrepancies noted in the previous literature orthodontist, Bolton's analysis regardless of malocclusion group, sex, and ethnicity is highly recommended.

The objective of this study was to revisit the topic of compensatory interactions between maxillary anterior teeth during development advanced by Sofaer et al. (1971). We addressed the hypotheses listed by Sofaer and colleagues using data derived from our Australian twin sample to investigate whether final tooth size in permanent maxillary central incisors and canines showed evidence of developmental compensation for adjacent missing or microdont lateral incisors. Such compensation is one factor interacting in the complex system of dental development.A 2D image analysis system was used to measure crown height from the labial view, labiopalatal crown width from the incisal view, and mesiodistal crown width from both the labial (MDl) and incisal (MDi) views of the permanent maxillary central incisors and canines on the dental study model of twins enrolled in a longitudinal study of dental development.Developmental variations of maxillary lateral incisors influence the morphogenesis of the adjacent teeth. For example, individuals with one missing lateral incisor and one lateral incisor of average dimensions, had significantly larger central incisors than the control group for the MDl and MDi dimensions (p 0.05). Of the 7 monozygotic twin pairs, 6 were discordant in maxillary anterior hypodontia and microdontia, and 13 out of 14 dizygotic twin pairs were discordant.This study provides further evidence of developmental interactions in the maxillary anterior region, partially supporting Sofaer and colleagues' hypotheses. These interactions are part of a complex adaptive system involving genetic, epigenetic and environmental factors.

Objective: To determine the anterior Bolton ratio for a Finnish adult population and to investigate its associations with overjet. Material and methods: This study is part of the Northern Finland Birth Cohort 1966. Clinical oral investigations, including three-dimensional intraoral scanning and registration of occlusion, were performed in connection with the 46-year follow-up for 1,961 subjects. Subjects with normal occlusion (n = 149), extreme overjet ≥ 8 mm (n = 49), large overjet 6–7 mm (n = 86), and negative overjet (n = 16) and no orthodontic treatment history were selected for further analysis. The mesiodistal widths were measured from canine to canine to evaluate the anterior Bolton ratio. Results: A mean anterior Bolton ratio of 78.6 (SD 3.1) was found for the normal occlusion group. Subjects with extreme overjet had smaller Bolton ratios compared to the normal occlusion group and the negative overjet group (p = .005, p = .019, respectively). Overjet deviations were associated with upper canine and incisor widths. Conclusions: The mean anterior Bolton ratio in subjects with normal occlusion was larger compared to the original Bolton ratio. Tooth size discrepancy was associated with extreme and negative overjet at population level.

Objective: Osteogenesis imperfecta (OI) is a rare, hereditary disease affecting collagen type-1 in connective tissue. Collagen type-1 is a substantial component of dentine, and it is speculated, whether affected dentine could cause altered mesiodistal tooth dimension possibly affecting restorative treatment regimen. Therefore, the aim of the present study was to measure mesiodistal tooth dimensions in individuals with OI and compare them with healthy controls. Materials and methods: Fifty-seven individuals aged 20–77 years with OI type 1–4 were included and 70 control patients aged 11–34 years were drawn from an orthodontic database. Mesiodistal tooth dimensions of all tooth types, except third molars, were measured in mm (two decimals) on digital 3 D-models of the tooth-bearing arches. Results: Multilevel mixed-effects linear regression analysis showed that mesiodistal tooth dimension on average was 0.17 mm (95% CI = (−0.33; −0.01)) reduced for the OI group compared to controls. The analysis revealed variation between tooth types; incisors and first premolars were most affected and molars minimally affected. Conclusions: The mesiodistal tooth dimension in individuals diagnosed with OI is significantly smaller compared to healthy controls, which should be taken into consideration in the restorative treatment planning of individuals with OI, although the magnitude of the deviation is relatively small. The results on mesiodistal tooth dimensions of the present controls may be used as a standard for comparisons in future studies on tooth dimensions.

Objectives: The objective was to develop an odontometric technique for sex estimation based on dental measurements from adult individuals, and to evaluate its applicability and reliability for diagnosis of sex of nonadult skeletal remains. Materials and methods: This study was conducted on the permanent dentition of 132 individuals (70 males, 62 females) from the identified human skeletal collection of the Certosa Cemetery (Bologna, Italy) of the University of Bologna. Binary logistic regression equations were developed based on dental measurements of the permanent teeth of the adult individuals, and these equations were subsequently applied to the permanent dentition of nonadult individuals to estimate their sex. Results: These data show that the canine teeth of both the maxilla and mandible are the most sexually dimorphic teeth in adults, followed by the mandibular second molar, maxillary and mandibular second and first premolars, and mandibular first molar. These data provided correct assignment of sex in 80.4–94.9% of cases, which depended on the measurements used. Of the 26 nonadult individuals of the experimental sample, sex diagnosis was possible for 22, which represented an applicability rate of 84.6% of the individuals. Comparing the sex of these 22 nonadult individuals estimated by odontometrics with the known biological sex, correct assignment was obtained in 90.9% of cases. Conclusion: As a method of sex estimation, odontometric analysis of permanent dentition can be used successfully for nonadult human skeletal remains in both forensic and archeological contexts.

Introduction: The purpose of this study was to seek and summarise the Bolton overall index (OI) and anterior index (AI) regarding normal occlusion and Angle’s malocclusion according to gender, and to assess if these indices support Bolton’s standards as general references. Methods: PubMed, LILACS, Embase, CENTRAL and Google Scholar databases were searched up to June 2019 (CRD42018088438). Non-randomised clinical studies, published in English and assessing Bolton’s OI and/or AI in normal occlusion and Angle’s malocclusion groups, were included. OI and AI means, sample size and SDs were collected. The National Heart, Lung, and Blood Institute’s Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to assess the risk of bias. Pairwise random-effects and multilevel Bayesian network meta-analyses were used to synthesise available data. Results: Fifty-three observational studies were included (11,411 participants; 3746 men, 4430 women; 15 studies lacked gender information). For normal occlusion, pooled estimates for OI and AI means were 91.78% (95% confidence interval [CI] = 91.42–92.14; I2 = 92.87%) and 78.25% (95% CI = 77.87–78.62; I2 = 90.67%), respectively. We could identify in Angle’s Class III patients meaningful OI and AI mean deviations from normal occlusion (0.76, 95% credible interval [CrI] = 0.55–0.98 and 0.61, 95% CrI = 0.35–0.87, respectively), while in Class II patients we found a meaningful mean deviation from normal occlusion only for OI (−0.28, 95% CrI = −0.52–−0.05). Concerning gender impact, male patients presented higher OI (0.30, 95% CI = 0.00–0.59) and AI (0.41, 95% CI = 0.00–0.83) mean values than female patients in Class I. Conclusion: Normal occlusion OI and AI mean values differ from Bolton’s original values. Class II division 2, for OI mean values, and Class III, for both OI and AI, are proportionally larger than normal occlusion patients. Gender had almost no impact on teeth mesiodistal proportion.

Objectives. To evaluate the tooth size discrepancy and Bolton’s ratios between male and female subjects with a Class I malocclusion. Materials and Methods. The digital e-models of 100 male and 100 female 12-year-old southern Chinese children with a Class I malocclusion were selected. The mesiodistal widths from permanent first molar to the contralateral side first molar of the upper and lower dentitions were measured. Differences between the tooth size discrepancy, together with the anterior and overall Bolton’s ratios between male and female subjects, were assessed using a two-sample t-test. A paired t-test was used to determine differences between antimetric pairs of teeth within the same arch. Results. Females had statistically significant smaller teeth than males (P < 0.05) except the upper left and lower left lateral incisor and lower left and right central incisors. The mean values of anterior Bolton’s ratios for males and females were 77.04 and 77.03, respectively (P > 0.05), while the mean values of overall Bolton’s ratios of male and female are 90.48 and 90.65, respectively (P < 0.05). The clinical significant differences (Cohen’s d > 0.2) for contralateral tooth size were shown on the maxillary canines, lateral incisors, and central incisors of males; and mandibular canines and lateral incisors of females. Conclusions. Southern Chinese females presenting with Class I malocclusions have smaller mesiodistal tooth dimensions compared to males. Both males and females presented several tooth size asymmetries. There are no statistical differences in anterior and overall Bolton’s ratios between the genders.

Objective:Children with cleft lip and palate are reported to be commonly associated with higher prevalence of dental anomalies such as hypodontia, supernumeraries, and abnormalities in tooth size, shape, and position. This study investigated the prevalence of dental anomalies in a longitudinal cohort of children with unilateral cleft lip and palate (UCLP).Design:The study was a retrospective analysis of radiographs, study models, and treatment notes.Patients:Sixty patients with repaired UCLP aged 13 years old with complete dental records dating from 5 years of age were included.Methods:Study casts, dental panoramic, anterior maxillary occlusal, and periapical radiographs of the patients were examined for cleft-sidedness, congenitally missing permanent teeth, supernumerary teeth, microdontic, and macrodontic teeth in the anterior maxillary region, presence of malformed permanent cleft-sided lateral incisor and its morphology (peg-shaped, conical shaped, canine-formed), positions of the permanent lateral incisors relative to the cleft side and presence of rotated cleft-sided central incisors.Results:Of the 60 patients studied, 63.3% had hypodontia, 21.7% had supernumerary teeth, 69.6% had microdontia, and 12.5% had macrodontia. All of the cleft-sided permanent lateral incisors had associated anomalies, with a large proportion (43.1%) missing; and when present in 31 subjects, the majority (90.3%) was positioned distal to the cleft. Most of the cleft-sided permanent central incisors were rotated if present, and prevalent at 86.7%.Conclusion:A high prevalence of dental anomalies was observed in this sample of children with UCLP.

Systematic study of dental attributes yields insights regarding diet and subsistence that cannot be gained from the archaeological record alone. This analysis documents occlusal tooth wear, tooth crown dimensions and dental pathology of an expanded dental sample from Harappa (2550–2030 cal BC; Pakistan). New floral and faunal evidence of subsistence indicates a mix of agriculture and pastoralism that can be integrated with evidence of dental attributes and disease to reveal the impact of Harappan diet on oral health. An enlarged dental sample (58 specimens, 910 teeth) from mature phase Harappa was analyzed using Scott’s quadrant wear system, measures of crown size, and prevalence of seven pathological dental lesions. All data were collected by the author using standard methods. Sex differences were found in wear, tooth size and prevalence of dental diseases. Females exhibit greater caries prevalence and antemortem tooth loss than men, an attribute associated with higher rates of pulp exposure and abscesses in women. At Harappa antemortem tooth loss results from penetrating caries, while in foragers the cause is severe occlusal wear. In contrast to early Holocene foragers of north India (Damdama, 8800–8600 BP), Harappans have greater occlusal wear, smaller teeth, and a distinct dental pathology profile.

Objective 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. Design 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. Results 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. Conclusion 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.

Objective:Researchers have documented secular trends in tooth size among recent generations. This study was a test for a change in mandibular leeway space.Materials and Methods:Dental casts from participants in the Denver Growth Study (23 boys, 22 girls; born in the 1930s) were compared with casts from a contemporary series of orthodontic patients (23 boys, 22 girls; born in the 1990s). All were phenotypically normal, healthy American whites.Results:Analysis of variance (accounting for sex) showed that the cumulative mandibular primary canine plus first and second primary molar size (c + m1 + m2) was slightly larger in the recent cohort (23.53 mm earlier vs 23.83 mm recent cohort; mean difference: 0.30 mm; P = .009), principally due to larger second primary molars (m2) in the recent cohort. In turn, the sum of the permanent canine and two premolars (C + P1 + P2) was significantly larger in the recent cohort (21.08 mm earlier vs 21.80 mm recent cohort; mean difference: 0.72 mm; P = .002). Larger teeth in the contemporary series produced a mean leeway space per quadrant of 2.03 mm versus 2.45 mm in the earlier cohort—a clinically and statistically significant reduction (P = .030). Some tooth types (primary second molar and permanent canine) were significantly larger in boys than in girls, but the sex difference in leeway space was not statistically significant.Conclusion:Results suggest that mandibular leeway space is decreasing in 21st century American whites and may present a challenge to orthodontists in managing tooth size–arch length discrepancies.

The purpose of this article is to present a simple method for determining the optimal sizes of anterior teeth. This is needed because of the frequency of anomalous and missing maxillary lateral incisors. In addition to anomalous and missing incisors, other factors that create challenges for the dentist and orthodontist when designing an esthetic and occlusally sound dentition are attrition, trauma, transposition, erosion, and caries. Optimal esthetics and occlusion require correctly sized teeth in proportion to themselves and the other teeth. Orthodontics, in partnership with restorative dentistry, allows doctors to accomplish the objectives of ideal occlusion and enhanced esthetics. Data compiled from previously published research enabled us to create simple formulae to determine optimal tooth sizes, an esthetic guide worksheet to use with collaborating dentists, and a sample written communication to accompany the completed esthetic guide worksheet. The method for establishing optimal tooth sizes is presented in a manner that allows easy memorization of the formulae and determination of the best dimensions for teeth without the use of a calculator.

Background: The relationship between tooth size and stature has been analysed extensively at the interspecies level but has received less attention at the intraspecies level. The relationship between these two parameters does not seem to be the same among modern human populations. Aim: The aim of this study is to analyse the relationship between tooth dimensions and body measurements in the Baka Pygmies. Subjects and methods: Height, weight, and tooth dimensions were obtained for 45 adult Baka females and 17 males from Le Bosquet (Cameroon). Correlations were obtained between the variables and compared to results for other human populations. Results: The Baka population is distinctive in the small number of significant correlations. Only two buccolingual diameters among Baka females show any significant correlation with height. The lack of significant correlations between tooth dimensions and body dimensions among the Baka means that changes in body size are accompanied by random variations in tooth dimensions. Conclusion: The absence of correlations may be accounted for by the impact of environmental effects on the somatic growth of the Baka producing a Pygmy phenotype adapted to live in the forest. It is worth noting that many correlations become significant when sexes are pooled. This research was funded by PICS 07492 MAMIBAKA, Wenner-Gren Foundation [grant No. 7819], National Geographic Society [grant No. 8863-10], and Agence National de la Recherche [ANR-11-BSV7-0011] to F.V.R.R. and Spanish Ministerio de Economía y Competitividad [grant Nos. CGL2011-22999 and CGL2014-52611-C2-1-P] to A.R.

Introduction: The determination of tooth size to arch length discrepancy in mixed dentition requires an accurate prediction of mesiodistal width of unerupted permanent teeth. Presently available methods use only the mesiodistal width of mandibular incisors. Melgaco (2007) introduced a new method of estimating width of unerupted canine and premolars by using mesiodistal width of incisors and first permanent molar. Aim: The aim of this study is to determine linear regression equation for estimating the widths of mandibular permanent canines and premolars using mesiodistal width of mandibular incisors and first molars in the Himachal population. Materials and Methods: Dental casts of 250 subjects were selected from the Himachal population who had fully erupted mandibular permanent incisors, canine, premolar, and first molar. Actual mesiodistal width of all fully erupted teeth were measured with digital vernier caliper and the values obtained were subjected to statistical and regression analysis. Results: High values of correlation (0.957) were found while considering Melgaco's method. Conclusion: From this study, it can be evaluated that Melgaco's method gives better prediction of unerupted permanent canines and premolars, and the equation Y = 13.48 + 0.614X can be suggested for the present population.

Objectives: To assess palatal vault height, tooth size, and dental arch dimensions in patients with unilateral and bilateral palatally displaced canines compared with a control group. Materials and Methods: A sample of 66 patients (mean age: 11.5 ± 1.0 years) with 22 unilateral palatally displaced canines (UPDCs), 22 bilateral palatally displaced canines (BPDCs), and 22 controls (C) were consecutively recruited. All three groups had dental casts that were scanned digitally using the OrthoX three-dimensional model scanner. Tooth size, palatal vault height, dental arch width, dental arch depth, dental arch length, and dental arch space were measured by the same examiner using the GOM software. Remeasurements were made in 10 randomly identified patients. Results: The palatal vault height was significantly lower in the BPDC group compared with controls. A significantly smaller mesial-distal crown width and, in general, more spacing in the maxilla were found in the UPDC and BPDC groups. No differences in arch length or arch width at the molar region were seen between the groups, while the arch length at the canine region was smaller in the UPDC and BPDC groups. However, this was observed in BPDC patients with both deciduous canines present and in most UPDC patients where the deciduous canine was present, compared with the control group, who had more permanent canines present. Conclusions: Patients with PDC had greater reduction in tooth size compared with the control group. The arch length and arch width were similar in patients with and without PDC.

Objectives: Odontometric studies of African populations show high within‐group variation in tooth size. Overall, North Africans exhibit smaller dimensions than groups from eastern and southern sub‐Saharan regions, but no previous studies have analyzed the full dental metrics among extant African Pygmy hunter‐gatherers and Bantu‐speaking farmers. Furthermore, the population variability in tooth crown sizes from equatorial rainforest regions remains to be elucidated. Materials and Methods: The mesiodistal and buccolingual diameters of the permanent teeth (I1‐M2) were measured in vivo using high‐resolution replicas from Baka Pygmies and Mvae and Yassa Bantu‐speakers from Cameroon (western Africa). Analyses of variance were used to record sex‐related and population‐level differences in tooth sizes, and a principal component analysis of geometrically scaled measures was used to plot the odontometric variability among groups. Results: Cameroonian Baka Pygmies differ in dental size from their Bantu‐speaking neighbors. Molar teeth are larger in Pygmies than in Bantu individuals, while the anterior dentition is larger in the Bantu. Baka males exhibit significantly larger teeth than females, whereas sexual dimorphism in non‐Pygmies is only present in the anterior dentition. Discussion: Odontometric patterns and the degree of sexual dimorphism in dental size differ among Central African groups, indicating adaptation to their different forager and farmer lifestyles. In particular, the admixture of Bantu‐speakers in Baka populations is smaller than that in other western Pygmy groups. The greater dental phenetic diversity in Baka compared to that of the smaller‐toothed farmers suggests that ecogenetic and microevolutionary factors are influencing a particular divergence scenario. Spanish Ministerio de Economía y Competitividad, Grant/Award Numbers: CGL2010-15340, CGL2011-22999, and CGL2014-52611-C2-1-P; Wenner-Gren Foundation, Grant/Award Number: 7819; National Geographic Society, Grant/Award Number: 8863-10; The French National Research Agency, Grant/Award Number: ANR-11-BSV7-0011.

The aim of this study was to investigate the prevalence of selected dental variations in association with infraocclusion, as well as determining the effects of infraocclusion on dental development and tooth size, in singletons and twins.Two samples were analysed. The first sample comprised 1454 panoramic radiographs of singleton boys and girls aged 8-11 years. The second sample comprised dental models of 202 pairs of monozygotic and dizygotic twins aged 8-11 years. Adobe Photoshop CS5 was used to construct reference lines and measure the extent of infraocclusion (in mm) of primary molars on the panoramic radiographs and on 2D images obtained from the dental models. The panoramic radiographs were examined for the presence of selected dental variations and to assess dental development following the Demirjian and Willems systems. The twins' dental models were measured to assess mesiodistal crown widths.In the singleton sample there was a significant association of canines in an altered position during eruption and the lateral incisor complex (agenesis and/or small tooth size) with infraocclusion (P0.001), but there was no significant association between infraocclusion and agenesis of premolars. Dental age assessment revealed that dental development was delayed in individuals with infraocclusion compared to controls. The primary mandibular canines were significantly smaller in size in the infraoccluded group (P0.05).The presence of other dental variations in association with infraocclusion, as well as delayed dental development and reduced tooth size, suggests the presence of a pleiotropic effect. The underlying aetiological factors may be genetic and/or epigenetic.

International audience; Objective: Accurate sex estimation is an essential step for the reconstruction of the biological profile of human remains. Earlier studies have shown that elements of the human permanent dentition are sexually dimorphic. The aims of this study are to determine the degree of sexual dimorphism in the dental tissue volumes and surface areas of mandibular canines and to explore its potential for reliable sex determination.Method The teeth included in this study (n = 69) were selected from anthropological collections from Spain, South Africa and Sudan. In all cases, the sex of the individuals was known. The teeth were scanned and three-dimensional (3D) measurements (volumes and surfaces areas) were obtained. Finally, a dsicriminant function analysis was applied.Results Our results showed that sexual dimorphism in canine size is due to males having greater amounts of dentine, whereas enamel volume does not contribute significantly to overall tooth size dimorphism. Classification accuracy of the multivariable equations tested on slightly worn teeth ranged from 78 to 90.2% for the crossvalidation, and from 71.43 to 84.62% for the hold-out sample validation. When all functions were applied together, the sex was correctly assigned 92.30% of the time.Conclusions Our results suggest that the 3D variables from mandibular canine dental tissues are useful for sex determination as they present a high degree of dimorphism. The results obtained show the importance of 3D dental tissue measurements as a methodology in sex determination, which application should be considered as a supplemental method to others.

It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard׳s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated.

OBJECTIVE: To evaluate and compare three-dimensional tooth size symmetry in the right and left sides of upper and lower dental arches in cleft lip and palate (CLP) patients and to compare it with an Angle Class I normal occlusion control group. MATERIALS AND METHODS: Dental casts of 72 individuals with CLP (20 bilateral [BCLP], 34 unilateral left [ULCLP], and 18 unilateral right [URCLP]) and 53 individuals with Class I occlusion, all with permanent dentition, were randomly selected. Mesiodistal (MD), labiolingual (LL), and occlusogingival (OG) measurements of upper and lower teeth were recorded with a digital caliper. Descriptive statistics and paired t-test were used for statistical analysis. RESULTS: Significant asymmetries were found between the right and left sides of the dental arches in CLP as follows: MD dimension: mandibular first premolar (ULCLP, P < .01); LL dimension: mandibular first premolar (URCLP, P < .05); OG dimension: maxillary central incisor and first premolar (ULCLP, P < .05 and P < .01, respectively), central incisor (BLCLP, P < .01), mandibular canine and first premolar (ULCLP, P < .01), and first molar (ULCLP, P < .05). Tooth crown size asymmetries were also recorded in the Class I group. CONCLUSIONS: Significant three-dimensional tooth size asymmetries were found in CLP subjects; however, such asymmetries were also present on the Class I control group.

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.

To compare mean anterior (AR) and mean overall (OR) tooth size ratios, prevalence of clinically significant tooth size discrepancies (TSDs) and correlation between AR and OR in subjects with Class II division 1 and Class III malocclusion treated by surgical-orthodontic or orthodontic means.Retrospective, cross-sectional.State-funded and private clinics.From pre-treatment cohorts of 770 surgical and 610 non-surgical subjects, Class II division 1 and Class III malocclusion groups were identified with 60 surgical and 60 non-surgical subjects, comprising 30 males and 30 females, in each.AR and OR were calculated by landmarking digital models. Differences in AR and OR and their relationship were analysed using two-way analysis of variance (ANOVA) and a correlation coefficient, respectively. The proportions of the surgical and non-surgical groups with a TSD were assessed using logistic regression. Intra-examiner reproducibility involved re-landmarking 30 randomly selected image sets and differences in ARs and ORs were compared using a paired t-test. Random error was assessed using the intraclass correlation coefficient (ICC). Analyses were performed using SAS (SAS Institute Inc., Cary, NC, USA) at the 5% level of significance.There were no statistically significant differences associated with the measurement of either the mean AR (P = 0·913) or the mean OR (P = 0·874). ICC values were very high (AR = 0·95; OR = 0·90). Differences existed between both Class II and Class III surgical (AR: P0·001; OR: P0·001) and non-surgical groups (AR: P = 0·012; OR: P = 0·003). The AR and OR relationship was strong (correlation coefficient = 0·72). The highest percentage of clinically significant TSDs was seen in the AR of both Class II and Class III surgical groups (23·3%).In the cohort examined: AR and OR differed significantly for malocclusion groups. The prevalence of clinically significant TSDs did not differ significantly between surgical and non-surgical groups although the highest percentage of clinically significant TSDs was recorded for AR in Class II and Class III surgical cases. AR and OR were closely related.

The aim of this study investigates mesiodistal crown size of the maxillary and mandibular incisors of patients with palatally impacted canines (PDC). Pretreatment dental casts of orthodontic patients with PDC of one or both maxillary canines (N: 33) were collected. This PDC sample was matched according to age and sex with pretreatment dental casts from unaffected orthodontic patients. For the PDC and matched control samples, maximum mesiodistal crown diameters were recorded for the four incisors on the right side only. The results showed that, on average, the mesiodistal crown diameters for the maxillary and mandibular incisors measured smaller in the PDC sample than in the control sample. These findings of statistically significant tooth-size reductions associated with PDC occurrence indicate a generalized pattern of reduced tooth size as a characteristic associated with the PDC anomaly. Further, the presence of generalized tooth-size reduction in cases with palatally displaced canines help explain why most orthodontic treatment plans for PDC patients are of the nonextraction type. How to cite this article Mahaini L. The Relationship between Palatal Displacement of Upper Canines and Incisors Widths in a Syrian Sample of Patients with Uncrowded Arches. J Contemp Dent Pract 2015;16(11):873-875

The human fossils, artefacts and faunal remains from the Middle Stone Age (MSA) deposits of Klasies River Main Site have featured prominently in discussions of the evolution of modern human morphology and the emergence of human behavioral modernity. Nearly 40 human fossils were uncovered by John Wymer's (1967-1968) excavations, and subsequent work by Hilary Deacon (1984-1995) has produced an additional dozen specimens. Many of the latter have been described, but most of the dental remains have been afforded only cursory mention and provisional identification. These specimens are documented here, and questions of individual association among some of the fossils from Wymer's excavations are also addressed. Three teeth provide the first indisputable evidence for juvenile individuals in the deposit. The proportion of juvenile to adult remains in the MSA levels at Klasies is notably lower than in other penecontemporaneous South African coastal MSA sites such as Die Kelders Cave 1 and Blombos Cave, where the proportion of juveniles is seemingly in closer keeping with coastal, geographically proximate Later Stone Age sites such as Oakhurst Shelter and Matjes River Cave. The sizes of most of the recently identified human teeth from Klasies seem to affirm at least one arguable aspect of morphometric modernity in the MSA at this site in the form of a tendency for tooth size reduction.

Purpose Numerous studies have shown that tooth size is an important key to ideal occlusion. Bolton (Angle Orthod 28:13, 1958; 48:504, 1962) described a constant ratio between the widths of the upper and lower teeth that must be present to achieve an optimal occlusion. The purpose of this study was to determine the incidence of Bolton discrepancies in patients with Class II malocclusion scheduled for mandibular advancement surgery. Patients and Methods This study included 126 patients (40 male, 86 female) with Class II malocclusion who had at least a mandibular advancement as part of their surgical treatment. The mesiodistal widths of the 6 anterior maxillary and mandibular teeth were measured on preoperative models using a caliper. The measurements were used to compute the anterior Bolton ratio. Results Seventy-three of 126 patients (57.9%) were found to have an anterior Bolton ratio greater than the Bolton norm, indicating too much lower tooth mass compared with the upper mass or too little upper tooth mass compared with the lower mass. Conclusion Tooth-size discrepancies are common in patients requiring mandibular advancement surgery. This can make it difficult to advance the mandible into a solid Class I relation at the time of surgery. Bolton discrepancies should be considered when planning treatment with presurgical orthodontics. In addition, if necessary, the width of the lower incisors should be decreased or a space distal to the maxillary lateral incisors should be created to allow the establishment of a solid Class I canine occlusion at the time of surgery.

Statement of problem: Agenesis of the maxillary lateral incisor is linked to differences in overall tooth size. Thus, the mesio-distal space required for final esthetic restoration in patients with missing one of both maxillary lateral incisors may be smaller. Purpose. The purpose of this study is to determine if a tooth size discrepancy exists in orthodontic patients with agenesis of the maxillary lateral incisor(s). Material and methods. Forty sets of dental casts from white orthodontic patients (19 male and 21 female) mean age 15.9 years were collected. All casts had agenesis of one or both maxillary lateral incisors. The teeth were measured with a digital caliper at their greatest mesio-distal width and then compared to a control group matched for ethnicity, age and sex. S One-way repeated measures ANOVA (��=.05) was used for statistical analysis. Results. Males in the test group had significantly smaller maxillary posterior teeth when compared to males in the control group, with differences ranging from 0.28-0.78mm. Females showed significantly smaller maxillary anterior teeth, with differences ranging from 0.22-0.42mm. The remaining maxillary lateral incisor was also significantly smaller (1.27mm difference) in the male and female unilateral agenesis test groups indicating higher incidence of ���peg��� laterals when compared to the control group. Conclusions. Agenesis of one or both maxillary lateral incisors is associated with a tooth size discrepancy. White males experienced smaller than normal posterior maxillary teeth and females showed smaller anterior maxillary teeth.

The purpose of this study was to compare the soft-tissue profiles of matched Class I adolescent European Americans and Mexican Americans. The secondary aim was to explain profile differences based on group differences in soft-tissue thickness, skeletal morphology, dental position, and tooth size.The study pertained to 207 untreated Class I adolescents, including 93 Mexican Americans and 114 European Americans. Lateral cephalometric and model analyses were performed to quantify morphologic differences. Two-way analyses of variance were used to evaluate ethnicity, sex, and their interaction.Mexican Americans had significantly (P0.05) greater lip protrusion and facial convexity than did European Americans. Mexican Americans had smaller craniofacial dimensions and larger teeth, resulting in maxillary and mandibular dentoalveolar protrusion. Mexican Americans also had thicker soft tissues and greater maxillary skeletal prognathism than European Americans. The combination of thicker soft tissues, maxillary skeletal prognathism, and dentoalveolar protrusion explained the protrusive lips of Mexican Americans. The greater facial convexity of Mexican Americans was due primarily to maxillary prognathism and mandibular hyperdivergence. Sex differences pertained primarily to size; the linear dimensions of the boys were consistently and significantly larger than those of the girls.European American normative data and treatment objectives do not apply to Mexican Americans. Knowledge of the soft-tissue, skeletal morphology, and dental position differences should be applied when planning treatment for Mexican American patients.

Teeth are brittle and highly susceptible to cracking. We propose that observations of such cracking can be used as a diagnostic tool for predicting bite force and inferring tooth function in living and fossil mammals. Laboratory tests on model tooth structures and extracted human teeth in simulated biting identify the principal fracture modes in enamel. Examination of museum specimens reveals the presence of similar fractures in a wide range of vertebrates, suggesting that cracks extended during ingestion or mastication. The use of 'fracture mechanics' from materials engineering provides elegant relations for quantifying critical bite forces in terms of characteristic tooth size and enamel thickness. The role of enamel microstructure in determining how cracks initiate and propagate within the enamel (and beyond) is discussed. The picture emerges of teeth as damage-tolerant structures, full of internal weaknesses and defects and yet able to contain the expansion of seemingly precarious cracks and fissures within the enamel shell. How the findings impact on dietary pressures forms an undercurrent of the study.

Objectives: The aims of this work were: firstly, to draw up tables of percentile tooth sizes similar to those of Sanin and Savara for three age groups of a Spanish population; secondly, to describe changes in tooth size between those groups over time, as well as observing any sexual dimorphism and, finally, to compare both the Spanish and Sanin and Savara's American population samples. Material and methods: The sample included 359 patients and was divided into three age groups: adolescents, young adults and adults, of both genders. After dental cast digitalization, mesiodistal tooth-size was measured on each dental cast using a digital method. Dental size tables organized by percentiles for each group of age and gender were drawn up. Percentiles under 30 were considered as small, between 30 and 70 as average, and above 70 as large. As symmetry was found between contralateral teeth, the mean between the teeth of the two semi-arches was considered. Results: The mesiodistal tooth sizes of adolescents did not present statistically significant differences between genders, in contrast to the two other age groups. Conclusions: Mesiodistal tooth diameters tended to diminish with age, especially in women, in the Spanish population. The values obtained for our dental tables, organized by percentiles, were slightly higher than those found by Sanin and Savara in an American population, especially for women. © Medicina Oral S. L.

Objective: To determine the prevalence of tooth size discrepancies (TSDs) in an Irish orthodontic population among different malocclusion groups. Materials and Methods: From 850 pretreatment sets of orthodontic models at a university clinic, 240 were selected with 30 female and 30 male sets for each malocclusion (Class I, Class II division 1, Class II division 2, and Class III). Digital models were produced, and the mesial and distal contact points were digitized to calculate overall and anterior tooth size ratios. The differences between the male and female groups and among the malocclusion groups were analyzed using two-way analysis of variance (ANOVA) (P , .05). Results: A clinically significant anterior TSD (more than two standard deviations from the Bolton means) existed in 37.9% of the subjects. No differences existed in the prevalence of overall TSDs between the male and female groups (P 5 .5913) or among the malocclusion groups (P 5 .0809). For the mean anterior tooth size ratios in the male group, the values for Class III and Class II division 2 were higher than in Class II division 1, and the value for Class II division 2 was higher than in Class I (P 5 .0184). Conclusions: The prevalence of anterior tooth size discrepancies in this sample of Irish orthodontic patients was 37.9%. There were no statistically significant differences in the prevalence of mean overall TSDs with regard to malocclusion or gender. In the male group, the mean anterior tooth size ratio was higher in Class III and in Class II division 2 malocclusion than in Class II division 1 and higher in Class II division 2 malocclusion than in Class I malocclusion. (Angle Orthod. 2011;81:130–133.)

A unifying theory has been proposed that links anomalies of tooth size and number. Application of this theory suggests that anomalies of tooth size and number may share a common aetiology but could also be predicted. This article highlights an association between macrodontia and hyperdontia as demonstrated by two clinical cases. These cases demonstrate a localized association and effect on the dentition and highlight the possible predictive application of this theory. Clinical Relevance: Clinicians should be made aware of the possibility of supernumeraries associated with macrodont teeth.

Aims: As part of ongoing studies of the aetiology of dental anomalies the aims of this study were to identify multiple components of tooth size of the upper permanent incisors in 34 patients with supernumerary teeth and to compare them with those in a control group to determine whether the presence of a supernumerary tooth has a local effect on the size of the surrounding dentition. Methods and results: The labial and occlusal aspects of the clinical crowns of the upper permanent central and lateral incisors on the study models of 74 subjects were digitally imaged and measured using an image analysis system and automated macro (34 patients with supernumerary in the upper incisor region: 17 males and 17 females and 40 controls: 20 males and 20 females). The macro-defined 17 variables from each view. From the labial view these were: the mesio-distal and occluso-gingival length and additional measurements along 25 and 75% of the mesio-distal line and at 25, 50 and 75% along the occluso-gingival line such that all these sub-divisions extended to the periphery of the tooth. From the occlusal view these were: the mesio-distal and labio-lingual lengths, and additional variables that sub-divided the mesio-distal again at 25 and 75% along the length and at 25, 50 and 75% along the labio-lingual dimension. Principal component analysis (PCA) was used to identify the key factors with the most random variability. Comparisons were then carried out between the supernumerary cases and control group using 2-way ANOVA. Seven factors of tooth size for the upper central incisors and eight factors for the upper lateral incisors were extracted. Most of these variables were found to be larger in the supernumerary group than in the control. Statistically significant differences were found for 5 out of 7 and 4 out of 8 for the upper central and lateral incisors respectively. Conclusions: A number of factors of tooth size were identified and found to be larger in the supernumerary group compared to the control (7 for upper central and 8 for upper lateral incisors); the majority reached the 0.05 significance level. Tooth crown size of the upper central incisor was affected more than that of the upper lateral incisor, supporting a local field effect. (C) 2008 Elsevier Ltd. All rights reserved.

Anomalies of tooth number may not be isolated conditions but may have wider associations in the development of the dentition including tooth size. This study aimed to examine links between hypodontia, supernumerary teeth and crown size, considering the effect on the development of the whole dentition and so increase understanding of the aetiology of these conditions.The patients, who were all of European ancestry, were 60 young adults (30 males and 30 females) with hypodontia and 60 age and sex matched controls together with 60 young adults (39 males and 21 females) with supernumerary teeth and 60 age and sex matched controls. Hand measurements of mesiodistal and buccolingual dimensions were made of the teeth on dental study models using Mitutoyo electric callipers. The mean value of two measurements was used and intra-operator and inter-operator reliability determined. Patients with hypodontia had smaller teeth than the control group and this difference was statistically significant (p0.05) for all teeth except the MD dimensions of 13, 23, 24 and 44. The difference in size was greatest for the BL dimensions in hypodontia patients. Further, the greater the number of missing teeth the smaller the tooth size. The hypodontia patients also showed higher variability in tooth dimensions than the control group. Patients with supernumerary teeth had larger teeth than the controls, with the greatest differences in the MD dimensions. In both hypodontia and supernumerary patients the differences in tooth size were generalised throughout the dentition.In anomalies of tooth number the size of teeth is also involved. In patients with hypodontia and supernumerary teeth the crown size of the whole dentition is affected. These findings are compatible with a multifactorial aetiology of these conditions.

The prevalence of microdontia, macrodontia, peg-shaped tooth, Carabelli's tubercle, protostylid, paramolar tubercle, central tubercle and palatal accessory cusp were examined in Japanese children. This study included 905 children with primary dentitions (mean age 4 years 7 months) and 745 high-school students with permanent dentitions (mean age 16 years 8 months). Microdontia, macrodontia, Carabelli's tubercle, protostylid and paramolar tubercle were more frequent in the primary dentition, whereas peg-shaped tooth, central tubercle and palatal accessory cusp were more frequent in the permanent dentition. The association between the presence of developmental anomalies and the size of the remaining teeth was significant in permanent dentitions. Both the literature and this study indicate that developmental anomalies of tooth number, size and morphology should be studied as a group rather than as isolates.

Objective: To identify the possible sex differences in anterior and overall tooth size ratios and to evaluate whether any differences exist in tooth size ratios and distributions of subjects with clinically significant tooth size discrepancies among Angle Class I, Class II, and Class III malocclusion groups with the corresponding skeletal characteristics in a Japanese population. Materials and Methods: Each malocclusion group comprised 60 subjects (30 males and 30 females). The mesiodistal width from first molar to first molar was measured on each pretreatment cast to the nearest 0.01 mm using digital calipers, and the anterior and overall ratios were calculated. Student's t-test, Welch t-test, analysis of variance, and χ2-test were performed for statistical analysis. Results: No statistically significant sex differences were found in anterior or overall ratio in any group. No significant differences in anterior or overall ratios were found among the malocclusion groups. No significant differences were found between the distributions of subjects with clinically significant tooth size discrepancies, categorized by the Bolton standard deviation definition and by the actual amount of change calculated for tooth size correction in millimeters, among the malocclusion groups except for the mandibular correction for the overall ratio between Class I and Class III subjects. Conclusion: Bolton's values can be used with confidence for the typical Japanese orthodontic population. The use of the actual millimeters of correction for the tooth size ratios could help orthodontists avoid underestimating the prevalence of clinically significant tooth size discrepancies.

SUMMARY The aims of this study were to determine the tooth size discrepancies (TSD) in a representative sample of Jordanian schoolchildren and to compare TSD between genders. Dental casts of 367 (174 males and 193 females; mean age 15.5 years) Jordanian schoolchildren were selected. Anterior and overall Bolton ratios were determined using a digital calliper. Differences between genders were analyzed using a t -test. The results showed that there were no signifi cant differences in the TSD between males and females. The percentages of subjects with more than 2 standard deviations for the anterior and overall ratios were 23.7 and 9.5, respectively.

Dental size and shape have been widely used to study biological relationships among human populations. Although several techniques have been proposed to quantify dental form, few attempts have been made to compare results obtained by application of different techniques. This work aims at comparing the information about size and shape of molar contours obtained from linear measurements, landmarks and semi-landmarks as well as evaluating the variation patterns among populations obtained by each method. The crowns of 35 permanent upper second molars belonging to archaeological samples from three regions of Argentina were analyzed. Buccolingual and mesiodistal crown diameters were measured and centroid size and crown index were used as size and shape descriptors, respectively. Likewise, four landmarks and 79 semi-landmarks were collected from the molar outline and relative warps (RW) analysis was performed on partial warps and uniform vectors; centroid size was estimated to summarize tooth size. The results indicate that size was consistently estimated by the three variable types. On the contrary, noticeable differences were found when the results of molar shape described by linear measurements were compared with those obtained using either landmarks or semi-landmarks. This study shows that considerable information about molar contour is added by using landmarks instead of crown diameters and that some morphological features, such as degree of cusp development, can only be captured by means of semi-landmark analysis. Finally, the interpretation of similarities among samples differs according to the selected description system.

Objective: To explore how many millimeters of tooth size discrepancy (TSD) are clinically significant, to determine what percentage of a representative orthodontic population has such a tooth size discrepancy, and to determine the ability of simple visual inspection to detect such a discrepancy. Materials and Methods: The sample comprised 150 pretreatment study casts with fully erupted and complete permanent dentitions from first molar to first molar, which were selected randomly from 1100 consecutively treated white orthodontic patients. The mesiodistal diameter tooth sizes were measured using digital calipers, and the Bolton analysis and the tooth size corrections were calculated by the Hamilton Arch Tooth System (HATS) software. Simple visual estimation of Bolton discrepancy was also performed. Results: In the sample group 17.4% had anterior tooth-width ratios and 5.4% had total arch ratios greater than 2 of Bolton's standard deviations from Bolton's mean. For the anterior analysis, correction greater than ± 2 mm was required for 16% of patients in the upper arch or 9% in the lower arch. For the total arch analysis, the corresponding figures are 28% and 24%. Conclusions: It is recommended that 2 mm of required tooth size correction is an appropriate threshold for clinical significance. A significant percentage of patients have a TSD of this size. Visual estimation of TSD has low sensitivity and specificity. Careful measurement is more frequently required in clinical practice than visual estimation would suggest.

Carabelli's trait is a morphological feature that can occur on the protocone of human maxillary molars. This study tests the hypothesis that Carabelli's trait is correlated statistically with the dimensions of the crown's four principal cusps or whether, as a cingular feature, the trait truly accretes onto an otherwise unaffected crown. Computer-assisted image analysis was used to measure the 6 intercusp distances and 12 angular relationships among cusp tips on the permanent first molar of 300 young adult American whites. Carabelli's complex was scored using an 8-grade ordinal scheme. Crown size was quantified in three ways, namely as 1) maximum mesiodistal and buccolingual diameters, 2) the 6 intercusp distances, and 3) the 12 angular cusp arrangements. There was no sex difference in the morphological expression of Carabelli's trait in this sample. Overall crown size and intercusp distances were significantly and progressively larger in molars with larger Carabelli's trait expressions. There are graded size responses between crown size (mesiodistal and buccolingual diameters), sizes of the four principal cusps, and morphological stage of Carabelli's complex, though the statistical relationships are appreciably stronger in males than females. Carabelli's trait occurs preferentially in larger molars. In contrast, angular (shape) relationships among cusp tips are not discernibly affected by trait size in either sex. There is the situation, then, that Carabelli's trait is developmentally correlated with crown size, but with no apparent alteration of cusp arrangements, suggesting that the increases are isometric across the occlusal table. Why the association is much weaker in females remains speculative, but these data provide yet another line of evidence that, within a population, tooth size is associated in a positive fashion with crown complexity.

Aim The aim of this investigation was to determine the tooth size ratio in an Iranian-Azari population. Method and Materials The Bolton tooth size analysis was performed on a sample of 50 plaster models (25 male subjects, 25 female subjects) of Iranian-Azari subjects. The mesiodistal widths of all teeth were obtained and the Bolton anterior ratio and overall ratio were calculated. The mean, range, and standard deviation were calculated for the anterior and overall ratio, and a coefficient of variation was obtained for the tooth size ratio. Results For the anterior ratio (3-3), the Iranian-Azari had a mean of 78.0 mm with a standard deviation of 3.1; the range was 73.68 to 84.6 mm. For the overall ratio (6-6), the mean was 92.0 mm with a standard deviation of 2.4; the range was 88.09 to 97.5 mm. Conclusions The results from the Iranian-Azari subjects in the study are similar to Bolton's original data for an American population. These values and the degree of variation were similar to the original data by Bolton, indicating the Bolton analysis for Caucasian samples can be transferred to an Iranian-Azari population. It also confirms no relevant sexual dimorphism exists, and these values are valid for both male and female subjects. Citation Mirzakouchaki B, Shahrbaf S, Talebiyan R. Determining Tooth Size Ratio in an Iranian-Azari Population. J Contemp Dent Pract 2007 November; (8)7:086-093.

Background To evaluate mesiodistal tooth width of patients with UCLP comparing tooth size in different Goslon Yardstick scores and between cleft and noncleft sides. Methods The Department of Orthodontics at Bauru Dental School and Hospital of Rehabilitation of Craniofacial Anomalies – University of Sao Paulo. Hundred forty-four pairs of dental casts of patients with UCLP. These dental casts were divided into 3 groups: group I (patients with Goslon rating of 1 and 2), group II (Goslon rating of 3) and group III (Goslon rating of 4 and 5). The control group consisted of 40 pairs of dental casts of noncleft Class I patients at the same age range. Mesiodistal width of maxillary permanent central incisors, lateral incisors and first molars were measured using a digital caliper. Intergroup comparisons were performed using ANOVA followed by Tukey tests. T tests were used to compare tooth size between cleft and noncleft sides (p

OBJECTIVE: Smile esthetics has become a major concern among patients and orthodontists. Therefore, the aim of this study was: (1) To highlight differences in perception of smile esthetics by clinicians, orthodontists and laypeople; (2) To assess factors such as lip thickness, smile height, color gradation, tooth size and crowding, and which are associated with smile unpleasantness. METHODS: To this end, edited photographs emphasizing the lower third of the face of 41 subjects were assessed by three groups (orthodontists, laypeople and clinicians) who graded the smiles from 1 to 9, highlighting the markers that evince smile unpleasantness. Kruskall-Wallis test supplemented by Bonferroni test was used to assess differences among groups. Additionally, the prevailing factors in smile unpleasantness were also described. RESULTS: There was no significant difference (P = 0.67) among groups rates. However, the groups highlighted different characteristics associated with smile unpleasantness. Orthodontists emphasized little gingival display, whereas laypeople emphasized disproportionate teeth and clinicians emphasized yellow teeth. CONCLUSION: Orthodontists, laypeople and clinicians similarly assess smile esthetics; however, noticing different characteristics. Thus, the orthodontist must be careful not to impose his own perception of smile esthetics. OBJETIVOS: a estética do sorriso tornou-se motivo de preocupação entre pacientes e ortodontistas. Diante disso, esse estudo objetivou (1) apontar as diferenças de percepção estética do sorriso entre grupos diferentes de avaliadores (clínicos, ortodontistas e leigos) e (2) avaliar entre fatores, como espessura de lábio, altura do sorriso, gradação de cor, tamanho dentário e apinhamento, quais estão implicados na desagradabilidade do sorriso. MÉTODOS: para tal, foram avaliados 41 indivíduos, com fotografias editadas, evidenciando o terço inferior da face. Essas fotografias foram avaliadas por três grupos (ortodontistas, leigos e clínicos), que graduaram os sorrisos com notas de 1 a 9 e apontaram marcadores que justificariam a desarmonia do sorriso. O teste de Kruskall-Wallis, complementado pelo teste de Bonferroni, foi empregado para verificação das diferenças entre os grupos de avaliadores. Além disso, os fatores mais prevalentes na desagradabilidade do sorriso foram descritos. RESULTADOS: não houve diferença significativa (p = 0,67) entre os grupos de avaliadores nas notas para avaliação do sorriso. Porém, os grupos apontaram características distintas, contribuindo para a desarmonia do sorriso. Para ortodontistas, a característica que mais contribuiu para a desarmonia do sorriso foi a pouca exposição gengival, enquanto, para os leigos, foram os dentes de tamanhos desproporcionais entre si, e, por último, dentes amarelados foram a característica mais observada pelos clínicos. CONCLUSÃO: concluiu-se que ortodontistas, leigos e clínicos, apesar de avaliarem similarmente a estética dos sorrisos, percebem características morfológicas diferentes. O ortodontista, portanto, deve ter cuidado sobre imposições de sua própria concepção de beleza do sorriso.