Effects of minor tooth movements on occlusal forces

Abstract

SUMMARY The aim of this study was to assess if minor tooth shifts, common with dental restorations and during orthodontic treatment, can substantially affect occlusal contact forces. Matched pairs of Dentsply Portrait IPN denture teeth with cuspal angulations of 0°, 20°, 33° and 40° were brought into occlusion by a weighted maxillary tooth. Each pair of teeth was positioned in three interocclusal molar relationships (Angle Class I, Class II and Class III) and 5 relative angulations, for a total of 60 control measurements. From each control position, the mandibular tooth, supported by a load cell, was moved 0.2 mm to the mesial, and in turn, 0.2 mm to the buccal. In each configuration, the three-dimensional loads (3 force and 3 moment components) on the lower tooth were measured by the load cell. It was found that the 0.2 mm tooth shifts substantially affected the occlusal contact forces with all interocclusal configurations and cusps. Current clinical concepts and guidelines oversimplify the complexity of the interactions of occlusal contact forces. Because the relationships between occlusal anatomy and tooth loads are so complex, more investigations are needed to establish the full extent of their potential clinical implications.