CONDYLE DISPLACEMENT ASSOCIATED WITH PREMOLAR EXTRACTION AND NONEXTRACTION ORTHODONTIC TREATMENT OF CLASS-I MALOCCLUSION

This study assessed condyle position change with premolar extraction a nd nonextraction orthodontic treatment in Class I malocclusions. Axial ly corrected pretreatment and posttreatment tomograms were obtained in 22 extraction and 13 nonextraction cases. Tomographic images were ran domized and blinded for joint space measurement. A total of 27 linear anterior, superior, and posterior joint spaces were obtained from each tomogram and averaged. Comparisons of pretreatment and posttreatment joint spaces between groups were done by t test (pool variance estimat e) with p < 0.05. Left and right anterior joint spaces were significan tly increased during orthodontic treatment of the nonextraction group. No other significant changes in condyle position were determined in e ither group. There were no significant correlations between mean joint space changes with length of Class II elastic wear. There was no sign ificant difference in condyle position change with extraction space cl osure using closing arch wires compared with alastic chain.