Comparison of Vertical Characteristics of Buccal Segments in Untreated Malocclusions

In this retrospective, cross-sectional study, our objective was to use a previously published cephalometric method to measure the maxillary and mandibular molar and premolar dentoalveolar heights of orthodontically untreated male and female subjects past their peak growth spurt as determined by CVMS stage V. Methods: A total sample size of 218 subjects with full permanent dentition that met defined inclusion and exclusion criteria, and grouping criteria were analyzed. Approximately 50% of the sample was obtained from the University of Illinois-Chicago Department of Orthodontics, and 50% from private offices. The sample was diverse in ethnic backgrounds and representative of an urban practice setting, with ages ranging from 13-56 years old. Using cephalometric gropuing criteria, subjects were then assigned to one of the following groups: Class I normodivergent, Class II hyperdivergent or hypodivergent, or Class III hyperdivergent or hypodivergent. Cephalometric images were traced using Dolphin Imaging (v11.7) and data was analyzed using independent t-tests, one-way ANOVA, and Bonferroni post-hoc tests (p<0.05), using SPSS statistical software (v22.0). Results: Several statistically significant differences in mean dentoalveolar height measurements were found when comparing Class I subjects to the other groups, and when comparing hyperdivergent groups to hypodivergent groups, and when comparing Class II groups to Class III groups. Statistically significant differences ranged from 1.11mm-4.55mm. Gender dimorphism was also demonstrated, both in mean differences in dentoalveolar heights, and in the magnitude of differences between groups of the same gender. Because of the gender dimorphism, all groups were also separated by gender. Conclusions: The comparisons in this study showed strong trends of short maxillary posterior dentoalveolar heights in Class II hypodivergent subjects, and short mandibular posterior dentoalveolar heights of Class III hyperdivergent subjects.