Assessing microleakage at the junction between amalgam and composite resin: a new method in vitro.

A new dye-diffusion test method was utilized to evaluate the microleakage between amalgam and composite resin. An amalgam cylinder was made to which a base of composite was added. The effects of several factors upon the microleakage were investigated. The test results indicated less microleakage when bonding agent was applied directly to the roughened amalgam prior to placement of composite resin. The most microleakage was found when roughened amalgam surface was acid-etched before placement of bonding agent and composite resin.