Predictors of outcome among patients with class II division 1 malocclusion treated with fixed appliances in the permanent dentition.

This retrospective study investigated the outcomes achieved in 212 consecutively completed patients with Class II Division 1 malocclusion (overjet > 6 mm). All patients were treated in the permanent dentition with upper and lower fixed appliances. A composite outcome measure was used to identify those cases with an excellent outcome (posttreatment PAR </= 5, posttreatment upper incisor to maxillary plane angle between 104.7 degrees and 115.3 degrees, and anterior movement of the lower incisors </= 2 mm). Logistic regression analysis with patient group as the dependent variable was used to evaluate the predictive value of 32 patient and treatment variables. The three outcome measures (posttreatment PAR score, posttreatment upper incisor inclination, and anterior movement of lower incisors) were ranked and combined to form a single continuous outcome variable. This was used as the dependent variable to carry out further analysis with the linear regression method. Both methods of analysis identified pretreatment overjet and pretreatment upper incisor inclination as significant predictors of outcome. The results revealed that in patients with large overjets an excellent outcome can only be predicted if the upper incisors are very proclined. Every 2 mm increase in overjet (above 4 mm) required approximately a 5 degrees increase in incisor proclination to achieve an excellent outcome.