Edgard Poiate Junior

Stress distribution in the cervical region of an upper central incisor in a 3D finite element model

The aim of this study was to evaluate the stress distribution in the cervical region of a sound upper central incisor in two clinical situations, standard and maximum masticatory forces, by means of a 3D model with the highest possible level of fidelity to the anatomic dimensions. Two models with 331,887 linear tetrahedral elements that represent a sound upper central incisor with periodontal ligament, cortical and trabecular bones were loaded at 45 masculine in relation to the tooths long axis. All structures were considered to be homogeneous and isotropic, with the exception of the enamel (anisotropic). A standard masticatory force (100 N) was simulated on one of the models, while on the other one a maximum masticatory force was simulated (235.9 N). The software used were: PATRAN for pre- and post-processing and Nastran for processing. In the cementoenamel junction area, tensile forces reached 14.7 MPa in the 100 N model, and 40.2 MPa in the 235.9 N model, exceeding the enamels tensile strength (16.7 MPa). The fact that the stress concentration in the amelodentinal junction exceeded the enamels tensile strength under simulated conditions of maximum masticatory force suggests the possibility of the occurrence of non-carious cervical lesions such as abfractions.

Evaluation of Stress Distribution in Implant-Supported Restoration Under Different Simulated Loads

Technical and scientific developments, in the form of osseointegrated implants, have made Restorative Dentistry evolve to become a highly successful form of treatment (Adell et al., 1981; Binon, 2000), considered as an additional safe tool oral surgeons have at their disposal to rehabilitate partially and totally edentulous patients. However, many negative factors can interfere in the treatment, causing clinical and functional complications that may culminate in the loss of osseointegration (Adell et al., 1981; Jemt et al., 1989; Naert et al., 2001a, 2001b; Isidor, 2006). The attachment of the crown to the abutment and of the latter to the implant, the loosening of the fixation screw, and even its fracture may arise from a poor distribution of occlusal loads in the prosthesis-implant set (Binon, 1994).