Studies indicate that tooth crown diameters are clinical markers for sex differentiation. Therefore, the aim of this study was to assess the degree of sexual dimorphism in different teeth. Maximum mesiodistal (MD) and buccolingual (BL) dimensions of 2400 permanent teeth from 100 pretreatment orthodontic dental study casts and clinical records (50 males and 50 females) from the Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Brazil, were examined. Comparison of the MD and BL dimensions between males and females was performed using the Student's t test with alpha 0.05, effect size, and discriminant function analysis. Comparisons in MD and BL widths between sexes demonstrated that the combined mean in the female group presented reduction when compared with the male group, except for the BL dimension of tooth 26. In regard to the MD dimensions, statistically significant differences were observed in various dental groups. The greatest sexual dimorphism was observed in the left mandibular canine (p<0.001) with effect size over 0.8 (0.94), which characterizes large effect. In BL dimension, numerous teeth demonstrated statistical differences between the sexes. Our findings reinforced the magnitude of sexual dimorphism in tooth size, and, in addition, highlighted the differences in specific dental groups.

ObjectivesTo evaluate the association between hypoxia during embryo development and oral clefts in an animal model, and to evaluate the association between polymorphisms in the HIF-1A gene with oral clefts in human families.Material and MethodsThe study with the animal model used zebrafish embryos at 8 hours post-fertilization submitted to 30% and 50% hypoxia for 24 hours. At 5 days post-fertilization, the larvae were fixed. The cartilage structures were stained to evaluate craniofacial phenotypes. The family-based association study included 148 Brazilian nuclear families with oral clefts. The association between the genetic polymorphisms rs2301113 and rs2057482 in HIF-1A with oral clefts was tested. We used real time PCR genotyping approach. ANOVA with Tukey's post-test was used to compare means. The transmission/disequilibrium test was used to analyze the distortion of the inheritance of alleles from parents to their affected offspring.ResultsFor the hypoxic animal model, the anterior portion of the ethmoid plate presented a gap in the anterior edge, forming a cleft. The hypoxia level was associated with the severity of the phenotype (p<0.0001). For the families, there was no under-transmitted allele among the affected progeny (p>0.05).ConclusionHypoxia is involved in the oral cleft etiology, however, polymorphisms in HIF-1A are not associated with oral clefts in humans.

Objective : Considering that oral clefts and tooth dimensions may be part of the same phenotypic spectrum, the aim of this study was to investigate tooth dimensions in permanent dentition and dental malformations, including tooth size discrepancies, of subjects born with clefts compared with individuals without clefts. Design : Cross-sectional study. Participants : The cleft group was composed of 66 subjects, and the noncleft group consisted of 66 healthy unrelated subjects. Main Outcome Measures : The mesio-distal and buccal-lingual crown diameter of fully erupted permanent teeth outside the cleft area was measured using a digital caliber. Clinical records and radiographs were used to evaluate the type of clefts and dental anomalies. Results : The lower second premolar was significantly reduced in the CLP and CP groups. The upper lateral incisor was found to be significantly smaller in the CP group, only for mesio-distal dimensions (P < .05). Dental agenesis was found in eight (12%) cleft subjects and supernumerary teeth in two (3%). Conclusions : Subjects born with oral clefts presented size reduction in specific dental groups.

FGF3 is associated with oral clefts and may interact with PAX9.

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