Background and Significance: The development of porcelain crowns for the predictable restoration of teeth has been brought about by the development of bonding techniques to enamel and dentin with the use of multi-step total etch adhesive systems along with the evolution in small particle hybrid resin composites as adhesive luting agents. One of the most common post-operative concerns of patients following delivery of full coverage crowns and bridges is sensitivity to thermal conditions in the mouth (cold water, ice cream, etc.) (Goodacre, Bernal et al. 2003). In order to understand the biological basis for these materials it is important to understand the anatomy and neurophysiology of dentin. The following is adapted from a paper provided by Dr. Charles Cox (Professor, University of Alabama School of Dentistry) concerning dentin structure and mechanisms for reduction of dentin hypersensitivity .