Comparison of occlusal loading conditions in a lower second premolar using three-dimensional finite element analysis

This study aimed to compare the patterns of stress distribution in a lower second premolar using three conventional occlusal loadings and two more realistic loading scenarios based on occlusal contact areas. The teeth of a dried modern human skull were micro-CT scanned in maximum intercuspation contact with a Viscom X8060 NDT X-ray system. A kinematic analysis of the surface contacts between antagonistic right upper and lower teeth during the power stroke was carried out in the Occlusal Fingerprint Analyser (OFA) software. Stress distribution in the lower right second premolar was analysed using three-dimensional finite element (FE) methods, considering occlusal information taken from OFA results (cases 4-5). The output was compared to that obtained by loading the tooth with a single point force (cases 1-3). Results for cases 1-3 differ considerable from those of cases 4-5. The latter show that tensile stresses might be concentrated in grooves and fissures of the occlusal surface, in the marginal ridges, in the disto-lingual and in the distal side of the root. Moreover, the premolar experiences high tensile stresses in the buccal aspect of the crown, supporting the idea that abfraction might be a dominant factor in the aetiology of non-carious cervical lesions. The application of FE methods in dental biomechanics can be advanced considering individual wear patterns. More realistic occlusal loadings are of importance for both new developments in prosthetic dentistry and improvements of materials for tooth restoration, as well to address open questions about the worldwide spread problem of dental failure.