Prognostic Indicators for Anterior Mandibular Repositioning in Adolescents with Class II Malocclusion: A Cross-Sectional Cephalometric Study

Abstract

Objective: To investigate the cephalometric changes following anterior repositioning of the mandible for predicting the treatment effects in Class II adolescent patients. Study Design: Lateral cephalograms of 28 patients (ANB > 4 degrees) were taken in centric occlusion (CO) and edge-to-edge bite (EtoE) before orthodontic treatment. The patients were classified into two groups according to their mandibular plane angle [MPA; low MPA (LMPA) <= 28 degrees and high MPA (HMPA) > 28 degrees]. Cephalomefric changes of hard and soft tissues were measured and analyzed with an x-y cranial base coordinate system. Results: For CO to EtoE, there were no significant cephalometric changes between HMPA and LMPA, but the horizontal ratio of soft to hard tissue pogonion (H-Pog'/H-Pog) change was significantly greater with LMPA than with HMPA while the vertical ratio (V-Pog'/V-Pog) showed vice versa. For CO to EtoE, MPA showed significant correlations with H-Pog'/H-Pog and V-Pog'/V-Pog. Y-axis angle, V-Pogr/V-Pog and H-Pog'/H-Pog can be used as good tools to discriminate between HMPA and LMPA. Conclusion: Cephalometric findings for CO to EtoE may be useful in predicting the vertical and horizontal changes of hard and soft tissues with the treatment of growing adolescents having various vertical skeletal patterns of Class II malocclusion.