MANDIBLE PHENOTYPE IN CLASS III SKELETAL MALOCCLUSION

Abstract

Objective: to evaluate the phenotypic characteristics of the mandible in Class III malocclusion in lateral cephalometric radiographs (LCR) and anteroposterior radiographs (APR). Materials and Methods: this is a retrospective observational study with a convenience sample. Individuals with Class III malocclusion were evaluated in 80 LCR (31 females and 49 males) and 70 APR (25 females and 45 males). In the control group, individuals with excellent occlusion were analyzed in

20 LCR and 20 APR (10 of each sex). The linear and angular measurements of the samples were tabled and submitted to the Shapiro-Wilk statistical test. Once their asymmetric distribution was known, the Mann-Whitney  U test was selected for comparison between groups and sexes, in addition to Pearson’s correlation coefficient test. Results: the length of the mandibular body, height of the ramus, height of the mandibular symphysis and alveolar processes, intercondylar distance, intergonion, and total length of the mandible were structural characteristics involved in the constitution of the skeletal disorder studied. Moreover, the spatial location of the mandible in relation to the maxilla and the base of the skull showed a strong influence on the configuration of this craniofacial disorder, evidenced by the protrusion of the mandible, an evident phenotype of the participation of this bone in Class III skeletal malocclusion. Conclusion: the involvement of structural and spatial characteristics of the mandible in relation to the maxilla and the cranial base in the constitution of Class III skeletal malocclusion was evident.