固定性ブリッジの保持に及ぼす各種合着材の影響 下顎第三大臼歯を支台としたブリッジ模型での評価

Abstract

The laboratory fixed partial denture models, made from Ni-Cr alloy or Au-Ag-Pd alloy, were used to measure the retentive force of one retainer (full cast crown) luted on the abutment before and after thermal cycling and to evaluate the retentivity and durability of various luting materials.Three types of conventional luting materials and two adhesive resins, 4 META-MMA/TBB resin and phosphate ester composite resin, were used.The retentive forces with adhesive resin, glass ionomer, polycarboxylate and zinc phosphatecements were 57.3-74.0, 26.3-30.6, 17.9-20.2 and 11.3-19.5 kgf respectively after 24-hour immersion in 37°C water (thermal cycle 0). There was no significant difference in the retentive force between Ni-Cr and Au-Ag-Pd alloy in all luting materials except phosphate ester composite resin. The retentive force with 4 METAMMA/TBB resin was significantly decreased by the thermal cycle test up to 50, 000 cycles, while those with other luting materials were hardly affected by thermal cycling.