冷热循环对载银软衬材料拉伸强度的影响

The effects of thermocycling on the tensile bond strength of silicone denture liner incorporated with silver-nano-particles

复合体组:载银软衬-树脂复合体8块,37℃蒸馏水浸泡24 h;复合体老化组:载银软衬-树脂复合体8块,冷热循环4 000次;基托树脂老化组:8对树脂块冷热循环4 000次后,制成载银软衬-树脂复合体8块。复合体组与复合体老化组拉伸强度(MPa)分别为2.683±0.435和2.179±0.633(P>0.05),试件断裂模式以内聚破坏为主。基托树脂老化组拉伸强度(MPa)为1.460±0.566(与前2组比较,P<0.05),试件断裂模式以粘接破坏为主。表明冷热循环对载银软衬材料拉伸强度无明显影响。

16 standered acrylic resin blocks with silicone resilient denture liner（10 mm ×8 mm ×3 mm）incorporated with nano-silver par-ticles at 5% （m/m,by dry wet）in-between were prepared.8 blocks were immersed in distilled water for 24 h at 37 ℃ as the controls （group 1）.Another 8 were thermocycled for 4 000 cycles（group 2）.16 acrylic resin bars were thermal cycled for 4 000 cycles.Then they were processed exactly as the control group （group 3）.Tensile bond strength of the specimens was measured by a universal testing machine. The bond strength values（MPa）of group 1,2 and 3 were 2.683 ±0.435,2.179 ±0.633 and 1.460 ±0.566 respectively（group 1 vs 2,P〉0.05;group 3 vs 1 or 2,P〈0.05）.The failure mode of the blocks in group 1 and 2 was mainly cohesive failure,in group 3 adhesion fail-ure.