Establishing the Customized Occlusal Plane in Systemized Surgical Treatment Objectives of Class III

Abstract

The purpose of this study was to present a new approach for establishing the customized occlusal plane for an individual patient in systemized surgical treatment objective of class III cases. After the correction of incisor inclination to occlusal planes (U1-MxOP and L1-MnOP), the intermaxillary relationship can be established with normal overbite/overjet and maximum intercuspation. The anterior limits of the maxilla and the mandible can be positioned according to A to N perpendicular, Frankfort horizontal (FH) to AB plane angle, and upper incisor display. The vertical level of the upper first molar can then be determined in relation to the Y plane (an imaginary arch drawn using the distance between the lower incisor edge point and the rotation center point of the condylar head as a radius) and a triangle projected by the upper and lower limits of the FH to the occlusal plane (FH-OP triangle). Soft-tissue facial balance can be checked with the lip/chin projection in relation to the true vertical line at subnasale and the lower third facial height ratio. Appropriate superior impaction of the posterior part of the maxilla in relation to the Y plane and FH-OP triangle in case 1 produced significant improvement of the facial profile and occlusion. However, case 2 showed that the amount of superior impaction of the posterior part of the maxilla was not enough to produce a significant setback of the mandible and retraction of the lip and chin. The systemized surgical treatment objective flowchart that could set the customized occlusal plane for an individual patient might provide a useful guideline for obtaining optimal aesthetics and functional occlusion in class III cases.