Stress Analysis of a Class II MO-Restored Tooth Using a 3D CT-Based Finite Element Model

A computational method has been developed for stress analysis of a restored tooth so that experimental effort can be minimized. The objectives of this study include (i) developing a method to create a 3D FE assembly model for a restored tooth based on CT images and (ii) conducting stress analysis of the restored tooth using the 3D FE model established. To build up a solid computational model of a tooth, a method has been proposed to construct a 3D model from 2D CT-scanned images. Facilitated with CAD tools, the 3D tooth model has been virtually incorporated with a Class II MO restoration. The tooth model is triphasic, including the enamel, dentin, and pulp phases. To mimic the natural constraint on the movement of the tooth model, its corresponding mandible model has also been generated. The relative high maximum principal stress values were computed at the surface under loading and in the marginal region of the interface between the restoration and the tooth phases. 1. Introduction Ethical concerns limit laboratory studies on living subjects, and advanced digital imaging technology has opened up new alternative possibilities in dentistry. The computational simulation method takes a more important position in both clinical and therapeutic applications in the dental industry [1]. Usage of virtual models offers an alternative method of investigation, and costs can also be reduced for in vivo and in vitro experiments. In dental research, CT scanning is the most frequently used high resolution imaging technology. To conduct CT scans, the targeted object needs to be exposed to a certain amount of ionizing radiation in which the absorbed radiation is detected and imaged later on. A series of sliced 2D images, depicting a density map of the scanned object, can be obtained. Piling these images creates a 3D description of the scanned area. The development of CT technology has been used to study and quantify the morphology of bone [2, 3], to nondestructively evaluate porous biomaterials [4], and to investigate the architecture of scaffolds [5, 6]. The offering of reasonably high resolution is the main reason for using CT as imaging technology in the field of hard tissue engineering. Contrast segmentation is a technique used for tissue differentiation, in which the grayscale of the layered contour images is determined by the tissue density. Living tissues involve complex shapes, for example, teeth and mandibles that are possible to be digitized using CT scanned images to allow accurate measurement of small changes of irregularities [7]. Ulusoy and Darendeliler [8]