A comparison of the effects of second molar and first premolar extractions on third molar position

Objective:To compare the changes in third molar position in patients treated with second molar and first premolar extractions. Method:The pretreatment and posttreatment cephalometric radiographs of 18 second molar extraction cases and 20 premolar extraction cases were analyzed. Vertical and horizontal drift and angulation of the third molar were measured. Changes in third molar position from pretreatment to posttreatment for two groups were compared. Result:Student t tests showed more vertical movement of the third molars during treatment in both arches of the second-molar-extraction patients than in the first-premolar-extraction patients. Statistically there were no significant differences in the change in third molar mesial movement. The mandibular third molars of the second-molar-extraction patients showed an improvement in angulation. Conclusion:Our results suggest that second molar extraction therapy may increase the rate of vertical movement of the third molar and improve the angulation of the mandibular third molars.