Impact of extracting the lower second premolar in adolescent on their third molar position

Objective To study the impact subjected by the third molar in adolescent due to exacting the lower second premolar. Methods Thirty-nine adolescents were chosen and divided into extraction and non-extraction groups, having 17 and 22 patients respectively. The pretreatment and posttreatment panoramic radiographs were measured to analyses the change of the third molar position. Results The third molar position were all improved from pretreatment to posttreatment in two groups. Compared with non-extraction group, the changes of the eruption space and third molar angulation in extraction group were all increased significantly in mandible. Conclusion Extraction of the lower second premolar could enlarge the eruption space of the third molar and upright the third molar, which is benefit to eruption of the third molar normally.