Aim: To cephalometrically compare the overjet, overbite, and molar and canine relationship stability of Class II malocclusion treatment with and without maxillary premolar extractions. Method: Two groups of 30 patients each with pre- and posttreatment matching characteristics and satisfactory finishing were used. Group 1 consisted of 30 patients treated with nonextraction at a mean pretreatment age of 12.14 years, while group 2 consisted of 30 patients treated with maxillary first premolar extractions at a mean pretreatment age of 12.87 years. Lateral cephalograms obtained before and after treatment and at a mean of 8.2 years after the end of treatment were compared. Student t tests were used to compare the initial and final dental relationships of the groups and the amount of treatment and long-term posttreatment changes. Pearson correlation coefficients were calculated to investigate correlations between treatment and long-term posttreatment dental relationship changes. Results: In groups with matching canine relationship treatment changes, long-term stability of the overjet, overbite, and molar and canine relationships were similar in the groups. There were significant but weak correlations between treatment changes in overjet, overbite, and canine relationships with their long-term posttreatment changes. Conclusion: Nonextraction and maxillary premolar extraction treatment of complete Class II malocclusion have similar long-term posttreatment stability in terms of overjet, overbite, and canine and molar relationships. ORTHODONTICS (CHIC) 2012;13:12–21.
Key words: Class II malocclusion, extraction, stability