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Simple Summary: Over the course of the past 3 million years, changes in human habitats, nutrition and behaviour have led to continuous processes of shape modification and size reduction in our jaws and teeth. These have resulted in the specific masticatory system observed today and the widespread need for orthodontic treatment. The aim of this study was to identify correlations between tooth sizes, jaw dimensions, biological sex and stature in a central European sample. We observed differences between women and men with regard to their tooth and jaw dimensions. In general, men's teeth, especially the canines, are larger. There are also differences in tooth sizes and jaw dimensions in relation to stature, with the canines again standing out. Our results help us to better understand the evolutionary trends affecting our teeth. They also indicate that, while the basic sexual dimorphisms of our primate ancestors have been retained, modern dietary habits will further intensify the reduction in the masticatory apparatus. Furthermore, the results provide sex-specific metric data of forensic significance, as well as clues as to why more and more people require orthodontic treatment, while suggesting possible causes for diachronic differences in tooth and jaw dimensions between populations. Dental anthropology provides a deep insight into biological, ecological and cultural aspects associated with human individuality, behaviour and living conditions and the environment. Our study uses a correlation analysis to test the metric relationships between tooth sizes and jaw dimensions and juxtaposes them with biological sex and stature. A sample of n = 100 dental casts was used to record metric dental data including the mesio-distal and bucco-lingual tooth crown diameters and nine upper and lower jaw dimensions. All crown diameters were highly correlated with both stature and biological sex, with the canines exhibiting the highest correlation. The majority of jaw dimensions exhibited similar correlations. Our results suggest that the differences between the sexes in most crown diameters and some jaw dimensions may be related to the stature of the individuals measured. Two groups of closely correlating features emerged among the jaw dimensions, differing in their degree of correlation with crown diameters and with sex. The results and insights obtained are highly relevant for evolutionary biology, dentistry, craniofacial research, bioarchaeology and forensic odontology. [ABSTRACT FROM AUTHOR]

Background/Aim: The aim of this study was to determine the accuracy of overall and anterior Bolton's ratio measurements obtained with an intraoral scanner compared to standard caliper measurements on plaster models. Material and Methods: This study included 33 subjects (18 female and 15 male), aged 12 to 18 years. All subjects were taken impression for the purpose of making study plaster models. In addition, all subjects underwent intraoral scanning for the purpose of creating digital models. Tooth width was measured with a caliper on plaster models, while digital models were analyzed using Cerec Ortho SW 2.0.2 software. The overall and anterior Bolton ratios were derived using both methods. Statistical data processing was performed using an independent t-test. Results: The results obtained using these two methods for measuring the anterior and overall Bolton ratio showed that there was no statistically significant difference in the measurements obtained on plaster models and the measurements obtained by intraoral scanning. For the overall Bolton ratio, T-test was 0.828 and is not statistically significant (p

Dental anthropology provides a deep insight into biological, ecological and cultural aspects associated with human individuality, behaviour and living conditions and the environment. Our study uses a correlation analysis to test the metric relationships between tooth sizes and jaw dimensions and juxtaposes them with biological sex and stature. A sample of n = 100 dental casts was used to record metric dental data including the mesio-distal and bucco-lingual tooth crown diameters and nine upper and lower jaw dimensions. All crown diameters were highly correlated with both stature and biological sex, with the canines exhibiting the highest correlation. The majority of jaw dimensions exhibited similar correlations. Our results suggest that the differences between the sexes in most crown diameters and some jaw dimensions may be related to the stature of the individuals measured. Two groups of closely correlating features emerged among the jaw dimensions, differing in their degree of correlation with crown diameters and with sex. The results and insights obtained are highly relevant for evolutionary biology, dentistry, craniofacial research, bioarchaeology and forensic odontology.

Abstract Background There have been reports of unique dental morphological features amongst Latin American and Hispanic populations, and this might invalidate the use of current orthodontic diagnostic tools within this population. There are no tooth size/tooth ratio normative standards for the Hispanic population, despite overwhelming evidence about differences in tooth size between racial groups. Objective This study aimed to determine whether there are significant differences in 3-D tooth shape between patients with Angle Class I, Class II, and Class III dental malocclusion in the Hispanic population. Methodology Orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III dental malocclusions scanned using an intra-oral scanner. The scanned models were digitized and transferred to a geometric morphometric system. Tooth size shape were determined, quantified, and visualized using contemporary geometric morphometric computational tools using MorphoJ software. General Procrustes Analysis (GPA) and canonical variates analysis (CVA) used to delineate the features of shape that are unique to each group. Result The study revealed differences in tooth shape between the different dental malocclusion groups on all twenty-eight teeth that were studied; the pattern of shape differences varied between the teeth and the dental malocclusions. The MANOVA test criteria, F approximations, and P-values show that shape in all the groups was significantly different

The pathogenesis of malocclusions, which are common among the population of all countries, is well represented in the professional literature. The occurrence of malocclusions is associated with genetic and various environmental factors. Among the latter, fluorides which affect the prevalence of some dental diseases are of particular interest. However, there are few publications reflecting the frequency of malocclusion among the population in the regions with different levels of fluoride in drinking water. This problem seems to be significant in the context of the increasing impact of fluorine compounds on human health, including dental health.The aim of the study. To analyze the literature on the frequency of malocclusion among the population living in conditions of variable fluoride content in drinking water. A manual search of domestic and foreign literature was performed in the search databases PubMed, Medline and Google Scholar. From the initial list of publications, eighteen articles that met the inclusion criteria for the study were selected for analysis. We revealed significant variability of the research results. Some authors note a higher prevalence of malocclusions among the population under conditions of increased fluoride intake, others note a lower one, and still others did not reveal any differences between the values obtained in both samples. Most of the assessed publications did not methodologically meet modern international standards, and therefore were of little evidence.The literature data do not provide grounds for an unambiguous assessment of fluorine compounds as an environmental factor that indirectly affects the process of occlusion formation in humans and animals.The review did not allow to make a definitive conclusion on the possible impact of systemic fluorides on the prevalence and pattern of malocclusion in humans and animals. It requires the implementation of studies that comply with the principles of evidence-based medicine.

Abstract Objective To find out if there is any relationship between tooth size discrepancy (TSD) and skeletal anterior open bite (AOB) and to assess the correlation between the amount of AOB and TSD. Method A total of 100 Class I subjects were included in this study (average age 15.21 ± 2.84 years). Fifty patients had skeletal AOB (>3 mm) and 50 subjects acted as controls and had a normal overbite. Teeth mesio‐distal widths were measured using a digital caliper. Anterior, overall, and posterior TSD ratios were calculated. An independent t‐test was employed to assess differences between groups and between genders. Pearson correlation coefficient was used to assess the correlation between the amount of AOB and TSD. Results Significant differences in anterior (p = .038) and posterior (p = .015) TSD ratios were detected. In the skeletal AOB group, no significant gender differences were detected (p > .05), whereas in the normal bite and total sample group, males had smaller posterior teeth compared to females (p .05). Conclusions Skeletal AOB had larger anterior and smaller posterior mandibular teeth, but the differences were less than 1 SD of Bolton's ratios. Males have smaller mandibular posterior teeth than females. The amount of AOB is not correlated with the TSD ratios.

Abstract Background An ideal relationship of anterior teeth is closely related to postoperative function, stability, and aesthetics. Therefore, it is necessary to estimate the proportion of anterior teeth when communicating with patients about possible treatment plans and outcomes. This study aimed to establish a simple method for assessing the proportion of anterior teeth and to identify the standard ratio value to provide references for clinical work. Methods Five hundred fourteen patients were divided into derivation, standard, and validation datasets. We first deduced our novel simplified anterior tooth ratio (SATR) by finding the key teeth with the derivation datasets, then established standard values by measuring the standard models, and finally validated the diagnostic performance of SATR. Independent sample t-test was used to select key teeth. Pearson’s correlation analysis and linear regression analysis was used to test and verify the correlation between SATR and the anterior Bolton ratio. Chi-square test and diagnostic test were used to verify the diagnostic results using SATR. P values of

Background: This study aimed to evaluate the tooth size discrepancy in patients with different types of malocclusions and compare it with that in patients with normal occlusion, using the three-dimensional (3D) measurement program Maestro Studio. Methods and Results: Patients of both sexes who were aged between 13 and 16 years and who had never received orthodontic treatment were randomly selected. The participants’ mean age was 14.3±1.1 years; 62.0% of patients were girls. Fifty patients were divided into three groups. Group 1 included 16 patients with malocclusion Class I (controls), Group 2 included 19 patients with malocclusion Class II division 1 (II/1), and Group 3 included 15 patients with malocclusion Class II division 2 (II/2). The tooth measurements were made according to the Bolton analysis. Anterior ratio (AR) and overall ratio (OR) were calculated. There was no significant difference in the AR between the groups. However, we found a significant difference in the OR between the groups (P=0.0129). Patients with Class II/2 malocclusion had a significantly lower OR than patients with Class II/1 malocclusion (P=0.0155). However, there was no significant difference in the OR between Class 1 and Class II/1 or Class II/2 malocclusions. Conclusion: Individuals with different malocclusions show different tooth sizes.

Background: There have been reports of unique dental morphological features amongst Latin American and Hispanic populations, and this might invalidate the use of current orthodontic diagnostic tools within this population. There are no tooth size/tooth ratio normative standards for the Hispanic population, despite overwhelming evidence about differences in tooth size between racial groups. Objective: This study aimed to determine whether there are significant differences in 3-D tooth shape between patients with Angle Class I, Class II, and Class III dental malocclusion in the Hispanic population. Methodology: Orthodontic study models representing Hispanic orthodontic patients with Angle Class I, II, and III dental malocclusions scanned using an intra-oral scanner. The scanned models were digitized and transferred to a geometric morphometric system. Tooth size shape were determined, quantified, and visualized using contemporary geometric morphometric computational tools using MorphoJ software. General Procrustes Analysis (GPA) and canonical variates analysis (CVA) used to delineate the features of shape that are unique to each group. Result: The study revealed differences in tooth shape between the different dental malocclusion groups on all twenty-eight teeth that were studied; the pattern of shape differences varied between the teeth and the dental malocclusions. The MANOVA test criteria, F approximations, and P-values show that shape in all the groups was significantly different < 0.05. Conclusion: This study revealed differences in tooth shape between the different dental malocclusions on all teeth, and the pattern of shape differences varied between the different dental malocclusions group. [ABSTRACT FROM AUTHOR]

Objective: To find out if there is any relationship between tooth size discrepancy (TSD) and skeletal anterior open bite (AOB) and to assess the correlation between the amount of AOB and TSD. Method: A total of 100 Class I subjects were included in this study (average age 15.21 ± 2.84 years). Fifty patients had skeletal AOB (>3 mm) and 50 subjects acted as controls and had a normal overbite. Teeth mesio‐distal widths were measured using a digital caliper. Anterior, overall, and posterior TSD ratios were calculated. An independent t‐test was employed to assess differences between groups and between genders. Pearson correlation coefficient was used to assess the correlation between the amount of AOB and TSD. Results: Significant differences in anterior (p =.038) and posterior (p =.015) TSD ratios were detected. In the skeletal AOB group, no significant gender differences were detected (p >.05), whereas in the normal bite and total sample group, males had smaller posterior teeth compared to females (p <.05). All the differences were smaller than 1 SD of Bolton's ratios. No significant correlation was found between the amount of AOB and TSD ratios (p >.05). Conclusions: Skeletal AOB had larger anterior and smaller posterior mandibular teeth, but the differences were less than 1 SD of Bolton's ratios. Males have smaller mandibular posterior teeth than females. The amount of AOB is not correlated with the TSD ratios. [ABSTRACT FROM AUTHOR]

Background: An ideal relationship of anterior teeth is closely related to postoperative function, stability, and aesthetics. Therefore, it is necessary to estimate the proportion of anterior teeth when communicating with patients about possible treatment plans and outcomes. This study aimed to establish a simple method for assessing the proportion of anterior teeth and to identify the standard ratio value to provide references for clinical work. Methods: Five hundred fourteen patients were divided into derivation, standard, and validation datasets. We first deduced our novel simplified anterior tooth ratio (SATR) by finding the key teeth with the derivation datasets, then established standard values by measuring the standard models, and finally validated the diagnostic performance of SATR. Independent sample t-test was used to select key teeth. Pearson's correlation analysis and linear regression analysis was used to test and verify the correlation between SATR and the anterior Bolton ratio. Chi-square test and diagnostic test were used to verify the diagnostic results using SATR. P values of < 0.05 were considered statistically significant. Results: Patients with an abnormal anterior Bolton ratio were more likely to have variations in the maxillary and mandibular lateral incisors. Therefore, the ratio of maxillary and mandibular lateral incisors was chosen as a simple way to assess the anterior tooth ratio and was defined as SATR (simplified anterior tooth ratio). A positive correlation was observed between SATR and anterior Bolton ratio (r = 0.702, p < 0.001), with the linear regression equation as follows: y = 0.503 + 0.328x, x = SATR, y = anterior Bolton ratio. The standard value of SATR was established (85.69% ± 3.57%) and proven reliable in clinical practice. Conclusions: The ratio of maxillary and mandibular lateral incisors can be used to estimate the anterior tooth ratio, which showed high reliability and efficiency. [ABSTRACT FROM AUTHOR]

Introduction/Objective. Hypodontia is a common dental anomaly that occurs either in a non-syndromic form or as a part of various syndromes. It is considered a multifactorial condition with genetic, epigenetic, and environmental influences, the interplay of which can lead to various anomalies in tooth size and number. The aim of this study was to assess mesiodistal tooth dimensions in Serbian hypodontia orthodontic patients and compare them to healthy controls using digital study models. Methods. Fifty subjects (30 females, 20 males) divided into two groups – 25 with hypodontia (15 females, 10 males) and 25 sex-matched controls (15 females, 10 males) – were included in the study. Alginate impressions were taken and plaster models poured, digitized, and imported into software where mesiodistal dimensions were obtained. Results. Intra-operator reliability was high. All teeth in the hypodontia group had smaller mesiodistal dimensions compared to controls. Statistical significance was noted for all teeth except for upper canines. No statistically significant differences were found between males and females in neither the hypodontia nor the control group, except for lower canines, which were significantly smaller in both hypodontia and control females. The most commonly missing teeth were upper lateral incisors, and lower and upper premolars. Conclusion. Hypodontia group presented with smaller mesiodistal dimensions compared to controls. The greatest difference in mesiodistal dimensions was found in upper lateral incisors and lower first molars. Lower canines were significantly larger in males compared to females in both groups.

Background and purpose: Esthetics is a major purpose in prosthetic treatments. Choosing the right size of anterior teeth in prosthetic and edentulous patients is a major challenge for both the patient and the dentist. This study was designed to obtain approximately close ratios for selection of anterior teeth. Materials and methods: This descriptive-analytical study, was performed in 121 patients. Measurements were performed using Vernier Caliper in contact with the soft tissue of the face with minimal pressure. Measurements were made while patients were in an upright position and their head was in a normal position. All patients occlusion was placed in centric relation (CO), and their lips were in resting position. The average amount of three measurements was recorded as the final result. SPSS V25 was applied for statistical analysis. Results: There were significant positive relationships between the size of anterior teeth and the distance between the two nasal tips (P=0.037) and between two nasal tips and canine to canine distance (P=0.014). No significant relationships were found between the size of anterior teeth and the distance between two zygomatic arches (P=0.947) and between the width of the anterior teeth and the distance between the internal and external meatus (P=0.297, P=0.952, respectively). Conclusion: The average size of facial and dental parameters was found to be different between men and women. The width and height of the face and the width and height of the maxillary central teeth were higher in men than women.

To determine the anterior Bolton ratio for a Finnish adult population and to investigate its associations with overjet. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Abstract Objectives Malocclusion 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. Results Class 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

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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. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to evaluate the association between genetic polymorphisms in RUNX2, BMP4, BMP2, TGFβ1, EGF, and SMAD6 and variations in permanent tooth size (TS). Materials and methods: This cross-sectional study evaluated 110 individuals' dental casts to determine the maximum tooth crown size of all fully erupted permanent teeth (third molars were excluded) in the mesiodistal (MD) and buccolingual (BL) dimensions. Genomic DNA was obtained from the epithelial cells of the oral mucosa to evaluate the genetic polymorphisms in RUNX2 (rs59983488 and rs1200425), BMP4 (rs17563), BMP2 (rs235768 and rs1005464), TGFβ1 (rs1800470), EGF (rs4444903), and SMAD6 (rs2119261 and rs3934908) through real-time PCR. The data were submitted to statistical analysis with a significance level of 0.05. Results: The genetic polymorphisms rs59983488, rs1200425, rs17563, rs235768, rs1005464, rs1800470, and rs4444903 were associated with MD and BL TS of the upper and lower arches (p < 0.05). The polymorphism rs2119261 was associated with variation in TS only in the upper arch (p < 0.05). The rs3934908 was not associated with any TS measurement (p > 0.05). Conclusions: In summary, this study reports novel associations between variation in permanent TS and genetic polymorphisms in RUNX2, BMP4, BMP2, TGFβ1, EGF, and SMAD6 indicating a possible role of these genes in dental morphology. Clinical relevance: Polymorphisms in odontogenesis-related genes may be involved in dental morphology enabling a prediction of permanent TS variability. The knowledge regarding genes involved in TS might impact the personalized dental treatment, considering that patients' genetic profile would soon be introduced into clinical practice to improve patient management. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background and purpose: Esthetics is a major purpose in prosthetic treatments. Choosing the right size of anterior teeth in prosthetic and edentulous patients is a major challenge for both the patient and the dentist. This study was designed to obtain approximately close ratios for selection of anterior teeth. Materials and methods: This descriptive-analytical study, was performed in 121 patients. Measurements were performed using Vernier Caliper in contact with the soft tissue of the face with minimal pressure. Measurements were made while patients were in an upright position and their head was in a normal position. All patients occlusion was placed in centric relation (CO), and their lips were in resting position. The average amount of three measurements was recorded as the final result. SPSS V25 was applied for statistical analysis. Results: There were significant positive relationships between the size of anterior teeth and the distance between the two nasal tips (P=0.037) and between two nasal tips and canine to canine distance (P=0.014). No significant relationships were found between the size of anterior teeth and the distance between two zygomatic arches (P=0.947) and between the width of the anterior teeth and the distance between the internal and external meatus (P=0.297, P=0.952, respectively). Conclusion: The average size of facial and dental parameters was found to be different between men and women. The width and height of the face and the width and height of the maxillary central teeth were higher in men than women. [ABSTRACT FROM AUTHOR]

Objective: The present study aimed to evaluate if genetic variants in PAX9, MSX1, TGFα, FGF3, FGF10, FGF13, GLI2 and GLI3 are involved in TS of permanent teeth. Materials and methods: Pretreatment dental records from orthodontic patients were assessed prior to recruitment. Patients with tooth agenesis and congenital anomalies (including oral cleft) and/or syndromes were excluded. Dental casts were used to measure the maximum crown dimensions of all fully erupted permanent teeth except second and third molars in mesiodistal direction. Teeth with caries, occlusal wear, mesiodistal restorations, and obvious deformities were not evaluated. Genomic DNA samples were used for genotyping. The allelic discrimination of 13 genetic variants was performed. The associations between TS and genotype were analyzed by linear regression, adjusted by gender at a significance level of p ≤ 0.05. Results: Genetic polymorphisms in the tooth agenesis–related genes studied here were associated with increased and decreased TS, in both maxilla and mandible (p < 0.05). Conclusion: This study reported associations of novel tooth agenesis–related gene variants with permanent tooth size variations. Clinical relevance: The presence of some genetic variants could allow the prediction of permanent tooth size. [ABSTRACT FROM AUTHOR]

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. Cross-sectional study. Orthodontic Clinic at School of Dentistry of Ribeirão Preto, University of São Paulo. A total of 108 orthodontic patients. 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. Female patients presented smaller tooth size than male patients. A statistically significant difference was observed in almost all teeth (P<0.05). The genetic polymorphisms in rs9340799, rs2234693, rs1256049 and rs4986938 were associated with some tooth sizes in both the maxilla and mandible (P<0.05). This study provides evidence that genetic polymorphisms in ESR1 and ESR2 could be associated with tooth size in permanent teeth. [ABSTRACT FROM AUTHOR]

Background Malocclusion characteristics vary across different ethnic groups and populations. Limited data are available regarding the characteristics of Syrian adolescents with Class II division 1 (Class II-1) malocclusion, and the recent inflow of Syrian refugees and immigrants into Europe and many areas worldwide demonstrate the need for updated studies to discover the craniofacial characteristics of these new immigrants. Objectives The present compound cephalometric and tooth-size study sought to assess the dentofacial morphology, upper-airway dimensions, and tooth-size characteristics of Syrian adolescents with Class II-1 malocclusion and compare the results with established Syrian population norms. Materials and Methods The study sample consisted of 43 Syrian patients including 24 females and 19 males with Class II-1 malocclusion (age: 14.3 (±1.5) years, mean (±SD)). Cephalometric radiographs and orthodontic casts were analyzed using special orthodontic software (OnyxCeph3™) and a universal digital caliper, respectively. Statistics were calculated using the SPSS software. Results In Syrian adolescents with Class II-1 malocclusion, the position of the mandible relative to the nasion perpendicular (mean (95% confidence interval)) was −11.01 (−12.45, −9.57) mm. Facial axis angle showed a negative value: −6.25 (−7.65, −4.85) degrees. An obtuse nasolabial angle was observed: 104.05 (101.77, 106.33) degrees. The average width of the upper pharynx was 11.50 (10.53, 12.47) mm; however, there was no prevalence of an upper-pharyngeal width of 5 mm or less. The average value of the anterior tooth-size ratio was 80.69 (79.85, 81.53) percent. In total, 39.5% of the investigated subjects had anterior ratios outside two standard deviations from Bolton’s norm, while 25.6% of the investigated subjects had anterior ratios outside two standard deviations from Syrian population norm. Conclusions In this study, the inter-maxillary discrepancy of Class II-1 Syrian adolescents was a consequence of their hyperdivergent facial pattern. The observed small pharyngeal widths were not clinically significant, while the anterior tooth-size discrepancy might be clinically relevant.

Background: Malocclusion characteristics vary across different ethnic groups and populations. Limited data are available regarding the characteristics of Syrian adolescents with Class II division 1 (Class II-1) malocclusion, and the recent inflow of Syrian refugees and immigrants into Europe and many areas worldwide demonstrate the need for updated studies to discover the craniofacial characteristics of these new immigrants. Objectives: The present compound cephalometric and tooth-size study sought to assess the dentofacial morphology, upper-airway dimensions, and tooth-size characteristics of Syrian adolescents with Class II-1 malocclusion and compare the results with established Syrian population norms. Materials and Methods: The study sample consisted of 43 Syrian patients including 24 females and 19 males with Class II-1 malocclusion (age: 14.3 (±1.5) years, mean (±SD)). Cephalometric radiographs and orthodontic casts were analyzed using special orthodontic software (OnyxCeph3TM) and a universal digital caliper, respectively. Statistics were calculated using the SPSS software. Results: In Syrian adolescents with Class II-1 malocclusion, the position of the mandible relative to the nasion perpendicular (mean (95% confidence interval)) was -11.01 (-12.45, -9.57) mm. Facial axis angle showed a negative value: -6.25 (-7.65, -4.85) degrees. An obtuse nasolabial angle was observed: 104.05 (101.77, 106.33) degrees. The average width of the upper pharynx was 11.50 (10.53, 12.47) mm; however, there was no prevalence of an upper-pharyngeal width of 5 mm or less. The average value of the anterior tooth-size ratio was 80.69 (79.85, 81.53) percent. In total, 39.5% of the investigated subjects had anterior ratios outside two standard deviations from Bolton's norm, while 25.6% of the investigated subjects had anterior ratios outside two standard deviations from Syrian population norm. Conclusions: In this study, the inter-maxillary discrepancy of Class II-1 Syrian adolescents was a consequence of their hyperdivergent facial pattern. The observed small pharyngeal widths were not clinically significant, while the anterior tooth-size discrepancy might be clinically relevant. [ABSTRACT FROM AUTHOR]

Objectives: Malocclusion 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. Results: Class 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. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Aims and Objectives: This study aimed to determine the biometric dimensions of three human permanent teeth in the occlusal/incisal-cervical and apical, buccolingual, and mesiodistal directions, and its relationship with age in adults in Shiraz, Iran. Materials and Methods: The samples included 50 upper canines, 50 maxillary first premolars, and 50 maxillary second molars, extracted from patients aged 25-55 years. Total length, crown labial surface length, crown palatal surface length, crown mesiodistal width, root length, and some other biometrical characteristics of the teeth were measured by using a Vernier caliper with 0.05-mm accuracy. The samples were divided into two age groups: patients aged below 45 years (younger adults group), and those aged over 45 years (older adults group). The data were analyzed by using independent t-test. P < 0.05 was considered as the significance level. Results: Most parameters such as the total length, crown mesiodistal and labiopalatal width, as well as the root length decreased in older adults group in all the three tested permanent teeth. Conclusion: During a lifetime, the crown length, mesiodistal, and buccolingual dimensions seem to decrease because of the physiological and pathological tooth wear. The tooth wear in a mesiodistal dimension is more frequent in posterior teeth than in the anterior ones. [ABSTRACT FROM AUTHOR]

Maxillary lateral incisors are only second to third molars, when it comes to variation in the form or morphology. Since the upper lateral incisors play an important role in the appearance of smile, any abnormality in their appearance or their complete absence, always attracts a great deal of attention. The prime objective of this study was to determine the prevalence of peg shaped and missing permanent maxillary lateral incisors in a Pakistani population. The total sample size for this study comprised of 650 patients (N = 650) belonging to both genders (Males: 350; Females: 300) and the age range of the participants was 18-25 years. The routine pre-orthodontic records were obtained. The intra oral clinical and radiographic examination was performed for peg and missing maxillary lateral incisors. Data were collected and analyzed statistically using chi-square test. The male participants had greater percentage of missing maxillary lateral incisors as compared to the females, but the difference was not statistically significant (p-value = 0.398). Females had greater prevalence of peg lateral incisors as compared to their male counterparts, but the difference was not statistically significant (p-value = 0.274). Maxillary lateral incisors are one of the forward-facing important tooth to achieve the pleasant smile and ideal occlusion. The peg shaped and missing maxillary lateral incisors leads to tooth size discrepancies, therefore they must be considered in orthodontic diagnosis and treatment planning. [ABSTRACT FROM AUTHOR]

Background and purpose: In tooth selection for dentures, the size of the tooth is really important. To estimate the size, a group of landmarks of the face have been investigated. This study evaluated the relationship between the length and width of maxillary central incisors and measurable indices of the face in patients with complete denture. Materials and methods: A descriptive-analytic cross-sectional study was done in 40 people (mean age: 55 years old) with complete denture in Dental Department affiliated with Mazandaran University of Medical Sciences, 2018. The width of the anterior maxillary teeth in the prostheses was determined based on the corners of the lips and the height of the teeth was determined based on the height of the wax-rim. We also investigated how close was the size of teeth arranged in dentures to interzygomatic width and face height. Results: The mean inter-zygomatic width was 118 mm in males and 120 mm in females, and the mean widths of the maxillary central incisors on dentures in males and females were 8.155 and 7.895 mm, respectively. There was no significant correlation between inter-zygomatic and maxillary central incisor width in dentures among males (P=0.204) and females (P=0.508). In this study, the teeth selected were wider and shorter than inter-zygomatic indices and facial height. Conclusion: The correlation between maxillary central incisor width and bizygomatic width could differ based on gender and genetic and geographical variations. Therefore, these indices should be investigated in different genetic populations. [ABSTRACT FROM AUTHOR]

Tooth morphogenesis involves dynamic changes in shape and size as it proceeds through the bud, cap, and bell stages. This process requires exact regulation of cell proliferation and differentiation. Smad7, a general antagonist against transforming growth factor-β (TGF-β) signaling, is necessary for maintaining homeostasis and proper functionality in many organs. While TGF-β signaling is widely involved in tooth morphogenesis, the precise role of Smad7 in tooth development remains unknown. In this study, we showed that Smad7 is expressed in the developing mouse molars with a high level in the dental epithelium but a moderate to weak level in the dental mesenchyme. Smad7 deficiency led to a profound decrease in tooth size primarily due to a severely compromised cell proliferation capability in the dental epithelium. Consistent with the tooth shrinkage phenotype, RNA sequencing (RNA-seq) analysis revealed that Smad7 ablation downregulated genes referred to epithelial cell proliferation and cell cycle G1/S phase transition, whereas the upregulated genes were involved in responding to TGF-β signaling and cell cycle arrest. Among these genes, the expression of Cdkn1a (encoding p21), a negative cell proliferation regulator, was remarkably elevated in parallel with the diminution of Ccnd1 encoding the crucial cell cycle regulator cyclin D1 in the dental epithelium. Meanwhile, the expression level of p-Smad2/3 was ectopically elevated in the developing tooth germ of Smad7 null mice, indicating the hyperactivation of the canonical TGF-β signaling. These effects were reversed by addition of TGF-β signaling inhibitor in cell cultures of Smad7-/- molar tooth germs, with rescued expression of cyclin D1 and cell proliferation rate. In sum, our studies demonstrate that Smad7 functions primarily as a positive regulator of cell proliferation via inhibition of the canonical TGF-β signaling during dental epithelium development and highlight a crucial role for Smad7 in regulating tooth size. [ABSTRACT FROM AUTHOR]

Introduction: Determination of sex is important in identification of unknown person. Teeth are a potential source for sex determination due to unique odontologic characteristics. Objectives: To determine the sex of individuals using buccolingual dimensions of permanent teeth except third molars. This study involved 100 native residents of Ahmednagar district, Maharashtra in the age group of 18–40 years. Materials and Methods: The buccolingual (B-L) dimensional measurements of 28 teeth, except third molars, of 50 males and 50 females aged 18–40 years were measured on the study casts using vernier calipers with a resolution of 0.01 mm, and analyzed using discriminant function analysis. Results: Males showed greater B-L dimensions of teeth in comparison to females exhibiting statistically significant dimorphism. However, discriminant function analysis derived accuracy of determination of sex using 26 was 69% and 43 was 66.0%. On the whole, the percentage of overall accuracy was 68%. Conclusion: Application of B-L dimensional variability among males and females in the population of Ahmednagar can aid in forensic sex determination, as this study showed, that can be taken into account for sex determination in combination with skeletal traits and/or other odontometric measurements such as mesiodistal diameters.

Introduction: There are several studies which evaluate the interactions of mesiodistal tooth size among Angle’s malocclusion groups. Gender dimorphism in tooth size has also been established in previous studies. However, there is lack of information regarding interactions between Angle’s classification, gender and individual tooth size. Aim: The aim of this study was to identify the Class of malocclusion more prone for gender dimorphism of individual teeth as well as the most variable and most homogenous teeth. Materials and Methods: The sample consisted of 308 study models with 104 belonging to Class I (53 males, 51 females), 104 to Class II division 1 (54 males, 50 females), and 100 to Class III malocclusion (50 males, 50 females). An electronic digital caliper was used to measure the mesiodistal width of all 14 maxillary and mandibular teeth from the right second permanent molar to the left. Statistical evaluation was done using independent t-test, analysis of variance and post-hoc Bonferroni test. Results: Class III malocclusions showed significantly larger dimensions in males for all teeth except upper central incisors and second bicuspids, whereas in Class II division 1, gender variations were limited to canines and upper second molars only. Class I showed gender dimorphism in canines, upper central incisors and lower first molars. Also, tooth dimensions were larger in Angle’s Class I and smaller in maxillary Class III in both genders. Conclusion: Gender dimorphism in tooth dimensions was found to be predominant in Class III malocclusion only. Canines were the most variable teeth showing gender variation in all three classes of malocclusion. The second premolars were the most homogenous, displaying no variations with gender in any of the classes.

Introduction: There are several studies which evaluate the interactions of mesiodistal tooth size among Angle's malocclusion groups. Gender dimorphism in tooth size has also been established in previous studies. However, there is lack of information regarding interactions between Angle's classification, gender and individual tooth size. Aim: Therefore, the aim of this study was to identify the Class of malocclusion more prone for gender dimorphism of individual teeth as well as the most variable and most homogenous teeth. Materials and Methods: The sample consisted of 308 study models with 104 belonging to Class I (53 males, 51 females), 104 to Class II division 1 (54 males, 50 females), and 100 to Class III malocclusion (50 males, 50 females). An electronic digital caliper was used to measure the mesiodistal width of all 14 maxillary and mandibular teeth from the right second permanent molar to the left. Statistical evaluation was done using independent t-test, analysis of variance and post-hoc Bonferroni test. Results: Class III malocclusions showed significantly larger dimensions in males for all teeth except upper central incisors and second bicuspids, whereas in Class II division 1, gender variations were limited to canines and upper second molars only. Class I showed gender dimorphism in canines, upper central incisors and lower first molars. Also, tooth dimensions were larger in Angle's Class I and smaller in maxillary Class III in both genders. Conclusion: Gender dimorphism in tooth dimensions was found to be predominant in Class III malocclusion only. Canines were the most variable teeth showing gender variation in all three classes of malocclusion. The second premolars were the most homogenous, displaying no variations with gender in any of the classes. [ABSTRACT FROM AUTHOR]

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 6 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. [ABSTRACT FROM AUTHOR]

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Abstract: 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. [ABSTRACT FROM AUTHOR]

We examined functional teeth (except for upper canine teeth) of Pacific walruses that died or were harvested on the coast of the Chukchi Peninsula in 2005, 2007-2008, and 2010-2011. The dynamics of deposition of annual cement layers was investigated. The rate of cement deposition on the walls of tooth roots decreased significantly with age. The rate of its deposition on the lingual side of the upper teeth was much higher than that on their buccal side, but no such differences were observed on the lower teeth. The same cement layer was deposited unevenly in different parts of teeth (on its different sides and levels) with a general tendency of increasing in the width of the layer from the top to the lower parts of teeth. As a result of local widening of some cement layers with age, the tooth surface became rough, and knolls and rollers appeared there. As the age increased, external changes in teeth occurred: they became larger, more rounded, and heavier. We described a method for the preliminary determination of the relative age of walruses based on the ratio between the width of cement and dentin on the attrition surface of lower teeth (without cutting). [ABSTRACT FROM AUTHOR]

The principal orthodontic problems observed in the mixed dentition phase are related to arch length and tooth size discrepancy. In order to identify such space discrepancies different methods of mixed dentition space analyses have been introduced. For this reason the purpose of this study is to generate a new regressive equation to predict the diameter of cuspid and bicuspid teeth through mesiodistal widths of lower incisors in a Chilean population sample between native and non-native population. The study was conducted at the Araucania Dental Clinic in Temuco, and the sample comprised of historical dental casts from 200 school children (93 boys and 107 girls) from Temuco, Chile, between 13-16 years of age. The native Mapuche population consisted of 107 students and the non-native of 93 students. Measurements of the mesiodistal widths of mandibular incisors, maxillary and mandibular canines and premolars were carried out with the help of Vernier gauge calipers calibrated to 0.01 of a millimeter. The results show that there are differences in the mesiodistal diameter size of incisors, and canines and premolars in the two studied groups. There is a low correlation of the variables studied. In conclusion, significant sexual dimorphism in tooth sizes exists in the native sample, and there is no difference in non-native population. It is necessary to develop a predictive formula that is greater than 70 % of accuracy for clinical application. Resonance imaging (MRI). [ABSTRACT FROM AUTHOR]