The bond interface between Silastic 891 and methyl methacrylate was evaluated to determine whether the use of primers would prevent leakage. Three different primers were tested, and the amount of leakage at the bond interface was evaluated by placing the test samples in India ink for periods of 12, 24, and 48 hours and 2 weeks. Of the 80 samples studied, 73 showed evidence of leakage-most of which occurred during the initial 12-hour test period.