Premolar extraction influence on third molar angulation

Objective: Previous studies evaluating premolar extraction influence on third molar angulation have combined first and second premolar extractions into a common extraction group. By combining the extraction groups, individual influences of each premolar have been negated. Separating the 2 extraction groups allows the influence of each premolar to be individually evaluated. Methods: In this retrospective study, 90 patients were divided into 3 groups of 30 patients each. Groups were determined by extraction pattern (nonextraction, first premolar extraction, second premolar extraction). The long axes of the second and third molars were traced on initial and final panoramic radiographs. The angulation change between the molars was determined between initial and final angulations. Results: There was not a significant difference in uprighting between the 3 treatment groups. Conclusion: Although the rationale that extraction of premolars could create a greater amount of retromolar space for third molars to upright and erupt into occlusion, our findings did not support this rationale.