[Studies on design for resin veneered crowns. 1. Adhesive resin luting agents reinforcement effect]

Resin veneered crowns show several drawbacks which affect the veneering resin: peeling, fracture, falling and also discoloration by leakages from the metal-resin border. The purpose of the present study is to find out a principle of resin veneered crown design allowing the solution of the above-mentioned problems. As a preliminary step, the influence of luting cements on the relative rigidity of veneered crowns and metal frameworks was examined by measuring the strain to static and impact charges on several portions of crowns. The investigation led to the following results: 1. The magnitude of the strain to a static charge increased with the number of shocks but beyond 100 shocks, no variation could be observed. 2. The magnitude of the strain to a static charge was proportional to the weight of the charge. 3. The strain of crowns and metal frameworks set with PanaviaEX had a magnitude smaller than the strain of those set with Fitchecker. 4. The strain to an impact charge had a magnitude 1-4 times larger than the strain to a static charge. 5. The adhesive resin luting agent reinforcement effect could be clearly confirmed.