Incisors Extrusion with Clear Aligners Technique: A Finite Element Analysis Study

Abstract

Since the low level of available evidence and the limited number of studies do not clarify whether clear aligners are a good option for extrusion, finite element (FE) analyses were performed to obtain more accurate biomechanical data about open-bite treatment in the upper arch. The aim of this study is to answer three questions: Are aligners efficient in performing upper incisor extrusion? Does the number, position, and shape of attachments influence the force system? Is posterior anchorage preserved during incisor extrusion? Six different simulations were performed with different attachment patterns. The results of this study were consistent with the biomechanical information obtained from clinical trials, and highlighted the need of better knowing undesired forces during teeth movement with clear aligners. Some attachment configuration seems to lead to a better force system. The presence of rectangular horizontal attachments on the buccal or palatal surface of upper incisors in combination with rectangular vertical attachments on posterior teeth was found to produce the most efficient force system with minimal aligner deformation.