Identification of Orthodontic Extraction Predictors in End-On Class II Malocclusion

Abstract

BJECTIVE: This study was designed to determine the different treatment predictors which help in the extraction and non-extraction decision of an end-on Class II malocclusion case. METHODOLOGY: The pretreatment records of 240 adult subjects aged 15-40 years with bilateral end-on Class II molar relationship were retrospectively selected and categorized under extraction (120) and non-extraction (120) treatment categories. The extraction cases were planned for different combinations of premolar extractions. The independent variables i.e., the cephalometric and orthodontic cast measurements were obtained from the recruited sample. Binary logistic regression analysis was applied using SPSS software. RESULTS: Increased upper and lower incisor inclinations (p < 0.001) and procumbent upper lip (p = 0.004) was statistically significant in the extraction group. According to the regression model, the odds of extraction treatment were 1.12 times greater than non-extraction treatment for every one degree increase in upper and lower incisor inclinations, respectively. The chances of extraction treatment were 1.6 times higher than non-extraction treatment for every 1 mm increase in the distance of upper lip to S-plane. CONCLUSIONS: The upper and lower incisors inclinations and upper lip position are the critical factors affecting the extraction decision in adult patients with end-on Class II molar relationships. Overjet, dental crowding and the vertical growth pattern were found to be clinically insignificant in opting for an extraction treatment plan for such cases. KEYWORDS: Treatment, Angle Class II, tooth extraction, non-extraction