Marginal leakage in amalgam restorations and its prevention.

Marginal leakage is the penetration of fluids, bacteria and ions into the space existing between all restorative materials and cavity walls. It can cause pulp irritation, colour changes in the tooth and secondary caries, and may result in failure of the restoration. The margins of a fresh amalgam restoration invariably leak. As time passes there is a decrease in marginal leakage related to the production of corrosion products and the spreading of certain materials into the space between the tooth and the restoration. Correct cavity margin preparation and proper condensation of the restorative material minimize marginal leakage round fresh amalgam restorations. Varnish coated on the cavity walls is most important and an indispensable method for preventing marginal leakage.