Relationship between malocclusion severity and treatment success rate in Class II nonextraction therapy.

ABSTRACT

INTRODUCTION: The purpose of this study was to evaluate the treatment success rate of Class II malocclusion without extractions, according to initial severity. METHODS: Class II subjects (n = 276) were divided into 2 groups according to the severity of the malocclusion. Group 1 comprised 144 patients with bilateral half Class II malocclusion at the initial mean age of 12.27 years. Group 2 comprised 132 patients who initially had bilateral complete Class II malocclusion at the initial mean age of 12.32 years. The patients' initial and final study models were evaluated with Grainger's treatment priority index. Chi-square tests were used to test for differences between the 2 groups for categorical variables. Variables regarding occlusal results were compared with independent t tests. RESULTS: Group 1 had a significantly better final occlusal result, a shorter treatment time, and a higher treatment efficiency index. CONCLUSIONS: Based on these results, it was concluded that bilateral half Class II malocclusion has a better treatment success rate than bilateral complete Class II malocclusion when treatment is conducted without extractions.