Stress Analysis of the Deciduous Tooth Using the Finite Element Method

Part 2: Depth of the Proximal Wall of Class II Cavity Preparation

Abstract

The analysis of the change and stress of the restoration was carried out regarding the depth and different materials employed in class II cavity preparation using the finite element method.
For the two dimensional finite element model for the primary teeth, the disto-lingaul section of the crown of the lower second primary molar was used as a standard. The cavity was conventional class II cavity. The restorative materials used were composite resin, silver amalgam and metal inlay.
The model of the class II cavity of the primary tooth was divided into 106points and 169 triangle elements. Displacement and stress figures were made, and the analysis was done for displacement of each point and the relative stress in the principal area.
The change in position of the tooth and the material at the mesial pit, peak mesial curvature of the tooth, axio-pulpal line angle and cervical marginal enamel were noticeable.
The degree of change in the position of restorative materials was low with resin, followed by amalgam and inlay. Furthermore, the deeper the proximal wall, the lower was the change. The stress in the restorative material in the occlusal portion was not related to the materials or to the depth of the proximal wall. However, in the proximal wall, the highest stress was found with the inlay followed by the amalgam and then resin. The deeper the proximal wall,, the more stress was concentrated in the bottom portion of the proximal wall.
The stress of the tooth was low with the inlay, followed by the amalgam and the resin. The differences in stress levels become incleasingly apparant when the depth of the proximal wall was increased.