Influence of first Premolar Extraction on Second and Third Molar Angulation - A Clinical Study

Background: In modern populations, the impaction rate is higher for third molars than for any other tooth. Due to the speculation of third molar role on late incisor crowding, many orthodontists prescribe removal of third molars before, during or just after orthodontic treatment. Objectives: The aim of this study was to compare whether orthodontic extraction of first premolar lead to any angular changes in second and third molars. Material and method: Orthopantograms of 20 patients undergoing orthodontic treatment were collected pre and post treatment. The patients were divided into two groups - nonextraction and extraction group. Each group consisted of 10 patients. The angles were measured between the long axis of 2^nd molar and 3^rd molar with horizontal plane. Changes in 2^nd and 3^rd molar angulation from pre-treatment to post treatment for two groups were compared by Mann- Whitney utest. Results: Statistical analysis revealed that maxillary and mandibular 2^nd and 3^rd molar showed an improvement in angulation but it was statistically non-significant. Conclusion: The findings of the present investigation suggest that premolar extraction therapy has a favourable effect on maxillary second&third molar angulation, while no changes in mandibular second&third molar angulation during treatment were found in patients treated with and without premolar extractions.