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Abstract
Esthetic dentistry has become increasingly important and a variety of esthetic restorative techniques have been devised and developed in response to the increasing demand (Hayashi et al, 1998 and Siervo et al 1994). This is due to the appearing issues concerning toxicity of amalgam restorations as well as the objectionable color imparted by metallic restorations.
The ideal restorative material should enable teeth, which have been subjected to a partial structural loss to be restored to their original function and appearance and keep this restoration level. At the same time, a seal should develop between the material and tooth so that bacteria loaded fluids cannot permeate the dentine and reach the pulp (Haak et al, 2003)
Polymerization shrinkage accomplished with curing resin composites may create gaps between the resin and the cavity wall/floor in three-dimensional cavity preparations if the forces of polymerization contraction exceed dentine bond strengths. Such gaps may create post-operative sensitivity and permit microleakage to occur. The magnitude of this phenomenon depends upon the configuration of the cavity and hence is called the cavity configuration (Yoshikawa et al, 1999b).