A radiographic comparison of the proclination of mandibular incisors between Class II extraction and non-extraction cases using the Damon® self-ligating system

Abstract

The stable position of the mandibular incisors, and the extent to which their spatial position may be changed in the sagittal plane, represents a key point in determining orthodontic treatment goals and objectives. According to the equilibrium theory, the mandibular incisors lie in a narrow zone of stability that is governed by pressure from the lips, cheek, tongue and periodontium. Proclining the mandibular incisors more than 2 mm leads to instability because of an increase in lip pressure. The magnitude of incisor proclination therefore determines aesthetics, stability and function.