A study to evaluate the changes in 3rd molar angulation with extraction of four premolars in class II malocclusion therapy

Abstract

Aim: The objectives of the study are to evaluate the changes in third molar angulation during orthodontic treatment with extraction of premolars in Class II malocclusions, and to evaluate the relationship between the angulation of third molars and positional changes of incisors and molars. Materials and Methods: This study was conducted on lateral cephalograms and dental panoramic tomograms of 30 patients (mean age 13.48 years) with skeletodental Class II malocclusion treated with four first premolar extractions. Twenty-four cases were treated with edgewise, and six were treated with Begg technique. The changes in the eruption pattern of the third molars were observed at the beginning of the treatment (T1) and at the end of the treatment (T2). The changes in the anteroposterior position of the incisors and molars, original molar space, and mesiodistal third molar angulation were tested by paired t-test. Results: The positional changes of the upper/lower incisors and first molars and original molar space were found similar in edgewise and Begg technique. Original molar space was increased in both jaws during orthodontic treatment. Long axis angle of the upper right third molar due to occlusal plane was increased nonsignificantly. Lower right third molars uprighted significantly. A positive correlation was found between the inclination of the lower right third molars and position of lower incisors and first molars. Conclusion: Treatment with extraction of premolars result in a greater space in the third molar region as a result of the mesial movement of the molars during space closure.