A Comparison of Craniofacial Characteristics between Two Different Adult Populations with Class II Malocclusion—A Cross-Sectional Retrospective Study

The dental, skeletal, and soft-tissue characteristics of a particular malocclusion can differ based on ethnicity, race, age, sex and geographical location with Class II malocclusion being one of the most prevalent malocclusions encountered in orthodontic clinical practice. The broad understanding of the characteristics of vertical skeletal and dental parameters in patients with Class II malocclusion can help clinicians to identify patterns and variations in the expression of this phenotype for better treatment outcomes. Hence, we compared the craniofacial characteristics of skeletal and dental Class II malocclusion traits from Indian and Vietnamese individuals to analyze the vertical skeletal and dental patterns in both population groups. The sample comprised of lateral cephalograms from 100 young adults with Class II malocclusion, of which fifty (25 males and 25 females) were from South India and the other 50 age- and sex-matched adults from Vietnam. The lateral cephalometric radiographs were digitized into anonymous image files and were traced and assessed for 16 vertical skeletal and dental parameters. The ANB angle was greater in males (+1.4 deg; p < 0.001) and females (+1.9 deg; p < 0.001) in the South Indian population. The Vietnamese males had a larger mandibular plane angle, articular angle, anterior facial height and lower anterior facial height compared to the Indian males. The Vietnamese females had larger mandibular plane and articular angles compared to the Indian females. The skeletal class II malocclusion was more severe in the South Indian compared to the Vietnamese adults. The Vietnamese sample showed a generalized tendency towards a more vertical skeletal growth pattern and in males this pattern seemed to be due to the dentoalveolar component. The Vietnamese females showed a tendency towards a vertical growth pattern, but without apparent contribution by the dentoalveolar component.

Evaluation of Dento-craniofacial Characteristics in Monozygotic Twins - Case Study

Introduction: Monozygotic twins are a valuable sample for the study of human craniofacial growth and development. Aims: The aim of the present study was to analyze the dento-craniofacial characteristics in monozygotic twins and to discuss the genetic, epigenetic and environmental influences in the twin’s phenotypic features. Material and Methods: Two 21-year-old female twins attended the Dental Service of Universidade Federal dos Vales do Jequitinhonha e Mucuri were analyzed. For validation of this study, a genetic test of zygosity was performed to confirm the individuals' monozygosity. Intraoral buccal examination revealed occlusal differences as well as disagreement in the eruption of the third molars. Results: The analysis of models showed differences in the mesio-distal diameter of the teeth of both arches, as well as disagreement in the perimeter of the mandibular arches between the two individuals. The cephalometric analysis showed remarkable differences in the vertical and horizontal parameters of the craniofacial structure. The SNA, SNB and LAFH showed differences of 10º, 9º and 3mm respectively. Additionally, the components related to the dentition also showed discrepant results. Conclusion: It can be suggested that the dento-craniofacial characteristics present a genetic component; however, the interaction of epigenetic and environmental factors can lead to different phenotypes in univiteline twins.

Craniofacial characteristics of Syrian adolescents with Class II division 1 malocclusion: a retrospective study

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.