The study on the adhesive durability of dental restorative composite resins by new testing mthod

比较了化学固化型（CCT）和光固化型（LCT）牙体修复复合树脂的粘接剪切强度和粘接耐久性。从牛牙的不同位置切下测试样本，制备直径为5mm的圆柱形洞，然后填充每种复合树脂。采用自行研制的推出剪切试验方法进行粘结剪切强度试验。在载荷幅值为50 N和100 N、频率为1 Hz、循环次数为1手千次的条件下，通过脉冲疲劳试验进行以带底空腔为试样的粘合剂耐久性试验，然后通过测量边缘泄漏来评价粘合剂耐久性。主要结果如下：1.推出剪切试验在所有类型的试样中，LCT树脂的粘结强度均高于CCT树脂。I型和II型（牙本质）的粘附强度相似，因此，很难肯定树脂标签对牙本质小管的锚定作用。它们的强度远低于IV型（釉质）。III型（牙釉质/牙本质）的强度介于I型和IV型之间。在III型的测试样本中，通过SEM照片观察到牙本质层的粘结界面上存在脱粘。粘结耐久性试验在脉冲试验后的牙釉质/牙本质试样中，证实了边缘渗漏，因此，重复加载似乎导致边缘部分的脱粘。在复合树脂/牙釉质粘接界面上也观察到了脱粘现象，这种剪切试验方法可用于评价复合树脂的粘接性能。

The adhesive shear strength and the adhesive durability of chemically cured type (CCT) and light cured type (LCT) of dental restorative composite resins were comparatively investigated. The test specimen cut from different locations on bovine tooth, cylindrical cavities 5mm in diameter were prepared and then filled with each composite resin. The test for adhesive shear strength was done using the push-out shear test method developed by the authors. The adhesive durability test of which the test specimen was the cavity with bottom was done by pulsating fatigue test in the conditions of load amplitudes of 50N and 100N,frequency of 1Hz and cycles of one handred thousand times, and then the adhesive durability was evaluated by measuring a marginal leakage. The following are major results :1. Push-out shear test In test specimens of all types, adhesive strengths of LCT resin were higher than those of CCT resin. Adhesive strength of Types I and II (dentin) were similar, consequently, it is difficult to positively confirm the anchoring effect of dentinal tubules by resin tags. And their strengths were much lower than those Type IV (enamel). Type III (enamel/dentin) showed an intermediate value between the strength of Type I and IV.In the test specimen of Type III,debonding was observed on the adhesive interface of the dentin layr by SEM photo.2. Adhesive durability test In test specimen for enamel/dentin after pulsating test the marginal leakage was verified, threfore, the repeated loading seemed to cause the debonding at a margin part. In adhesive interface of the composite resin/enamel the debonding was also observed from SEM photo.Such the shear test methods appear to be useful in evaluting the adhesive properties of composite resin for dental use.