Investigation of accuracy in pre-surgical orthodontic treatment for establishment of an evidence-based critical pathway for orthodontic/surgical combined treatment

Abstract

A critical pathway helps to organize patient' s care and eliminates variations created by doctors' different experience. In order to establish a critical pathway for orthodontic/surgical combined treatment, we investigated the accuracy of pre-surgical orthodontic treatment concerning relationships between incisors, occlusal plane angle and amount of mandibular setback. The following results were obtained. As for the prediction of mandibular setback, the differences between before and after pre-surgical orthodontic treatment ranged from -2.7mm to +2.9 mm horizontally and from -5.9mm to +2.4 mm vertically. The differences between these two predictions of mandibular setback were evaluated by multiple regression analysis. The dependent variables were the horizontal and vertical differences in these predictions. The independent variables were the difference between the position of U1 predicted initially and the position after pre-surgical orthodontic treatment, the difference between positions of L1 and the difference between occlusal plane angles. The horizontal difference was related to the following variables : the horizontal difference of U1, the difference of occlusal plane angle, the horizontal and vertical differences of L1. The vertical difference was related to the vertical differences in U1 and the vertical differences in L1. The results suggest that attention should be given to the positions of the incisors, not only horizontally but also vertically, in order to perform mandibular setback as accurately as that predicted initially. Therefore, we should establish a critical pathway that enables evaluation of the positions of incisors during pre-surgical orthodontic treatment and improve the accuracy for the tooth movement.