IADR Abstract Archives
Evaluation of bonding durability to CAD/CAM crowns
Objectives: The aim of this study was to evaluate the influence of the resin cement film thickness on the retention of CAD/CAM composite crowns using a cyclic loading test.
Methods: Abutment models were machined from titanium alloys with a 5-axis milling unit(GM-1000, GC). Molar crowns with cementation space of 100, 300 and 600 micro meters were fabricated from CAD/CAM blocks(Cerasmart(GC), HC(Shofu), LAVA Ultimate(3M)), and they were cemented to the abutment with resin cements(G-CEM Cerasmart(GC), Resicem(Shofu), RelyX Ultimate(3M)) by self-curing mode. The specimens were soaked in 37degC distilled water for 24hours. Using Instron universal tester(E1000) at a 30degree angle with respect to the specimen axis, and cyclic loading test was carried out at loads 50N-500N, 100,000cycles, 15Hz. TBS was tested by AG-I/20kNT(Shimadzu, cross head speed 1mm/min., n=3). And after load, some specimens were placed by thermal cycling (10,000cycle, 5-55degC). The results were analyzed by one-way ANOVA and Turkey test.
Results: The results showed that the bond strength decreased with the increase of cement film thickness.
Conclusions: Bond strength of each CAD/CAM block decreased by the increasing cement film thickness, because the stress has concentrated to the cement layer, which has the lowest elastic modulus between CAD/CAM block and abutment. From these results, we conclude that the cement film thickness affects bonding durability of resin cement to CAD/CAM composite block.
Methods: Abutment models were machined from titanium alloys with a 5-axis milling unit(GM-1000, GC). Molar crowns with cementation space of 100, 300 and 600 micro meters were fabricated from CAD/CAM blocks(Cerasmart(GC), HC(Shofu), LAVA Ultimate(3M)), and they were cemented to the abutment with resin cements(G-CEM Cerasmart(GC), Resicem(Shofu), RelyX Ultimate(3M)) by self-curing mode. The specimens were soaked in 37degC distilled water for 24hours. Using Instron universal tester(E1000) at a 30degree angle with respect to the specimen axis, and cyclic loading test was carried out at loads 50N-500N, 100,000cycles, 15Hz. TBS was tested by AG-I/20kNT(Shimadzu, cross head speed 1mm/min., n=3). And after load, some specimens were placed by thermal cycling (10,000cycle, 5-55degC). The results were analyzed by one-way ANOVA and Turkey test.
Results: The results showed that the bond strength decreased with the increase of cement film thickness.
Conclusions: Bond strength of each CAD/CAM block decreased by the increasing cement film thickness, because the stress has concentrated to the cement layer, which has the lowest elastic modulus between CAD/CAM block and abutment. From these results, we conclude that the cement film thickness affects bonding durability of resin cement to CAD/CAM composite block.