[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.
Fracture mechanics analysis of the durability of resin-bonded bridge. The effect of resin-bonded bridge design parameters on crack growth along adhesive layer.
The effects of resin-bonded bridge geometry on crack growth along the adhesive layer were analyzed by the use of elastic energy release rate g concept, together with the finite element technique. The values of g and the critical load for crack propagation in the adhesive layer are presented for various horizontal crack length a*, safety factor n, and metal frame configuration and thickness tm. Based on this analysis, suggestions for the design of resin-bonded bridge are suggested, in order to increase its durability.
Pitting corrosion for retaining acrylic resin facings.
1. Pitting corrosion provides undercuts suitable for retaining a resin facing. 2. Using a cathode with a proper shape, pits were uniformly distributed on the surface of a metal casting. The size of pits varies, depending on the time of pitting treatment. 3. The retentive pits were excellent in both retentive strength and marginal sealing when compared with spherical powder and beads.