Component analysis of craniofacial relations in various malocclusions -

Abstract

Linked principally to skeletal Class III malocclusion, mandibular macrognathism might exist in other malocclusions.Aims: 1) Characterize the traits of Class III and Class II malocclusions compared to a control group of Class I malocclusion. 2) Explore the existence of mandibular macrognathism in all types of malocclusion and its prevalence in Class III and Class II division 2 types. 3) Demonstrate particular traits to Class II division 2 that set it apart from all other malocclusions.Methods: 322 subjects were divided into 4 malocclusion Classes: I, II division 1, II division 2 (itself stratified into 4 subtypes), and III. Cephalometric linear and angular measurements gauged sizes and positions of the jaws and their relationships to each other. Statistics included a multivariate analysis of variance for group comparisons, frequency distribution, correlations, linear and logistic regressions.Results: Components of Class II division 2 were distinct from other malocclusions: maxilla closer to Class II division 1, mandible closer to Class I and Class III. In adults, 13.88 percent of Class III, 2.77percent of Class II.2, 0percent of Class II.1, had mandibular length (Co-Gn) beyond 1 standard deviation of the mean Class I mandibular length. In Class II.2 27.53percent had mandibular length comparable to that of Class II.1, 56.56percent comparable to that of Class I and 15.94percent to Class III. ANB in Class II.2 in ~60percent of the cases was comparable to Class I ANB (0-4.5˚), and ~40percent to Class II.1 (4.6-10˚). Chin components were characteristic in Class II.2: increased anterior symphyseal angle and distance Go-Pog. Conclusion: The results indicate that Class II division 2 may be a dentoalveolar malocclusion grafted on skeletal patterns ranging across other types of malocclusion. Longitudinal research with a larger sample is warranted. Findings on other malocclusions corroborate previous knowledge.