Marginal Leakage Around Fixed Dental Prosthesis - A review

Abstract

Marginal leakage is the intrusion into the space between all the restorative materials and cavity walls of fluids, bacteria, and ions. It can cause irritation of the pulp, change of color in the tooth and secondary caries, and may also result in restoration failure. The freshly placed prosthetic margins invariably leak. As time goes by there is a rise in marginal leakage associated with the manufacture of corrosion products and the expansion of other materials into the space between the tooth and the prosthesis. Dental researchers have been interested in the efficacy of the restorative materials to seal cavity margins against the entry of salivary constituents for some time. Some studies have shown that normal dentin would allow the penetration of dyes into human teeth's dentinal tubules. An analysis of later micro-leakage studies reveals that the structure of the dentin is permeable to the diffusion of fluids by natural and acquired defects. Because the enamel surface contains natural cracks and lamellas that allow the fluid to penetrate, the enamel can also have areas of hypo calcification, hypoplasia, chemical breakdown, abrasion, and carious lesions that increase penetration. However, dentine enables the transportation of fluids by odontoblastic processes. Cutting dentin with dental pressure increases the exposed surface area and thus increases the amount of tubules available for fluid transfer into the pulp chamber. While ionic charge and chemical reactivity of diffusing fluids lead to marginal leakage, the physical and chemical character of restorative materials, and the operator's clinical skills are equally essential.