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

比较研究了化学固化型（CCT）和光固化型（LCT）牙体修复复合树脂的粘接抗剪强度和粘接耐久性。在牛牙的不同位置切割试样，制备直径为5mm的圆柱形空腔，然后填充每种复合树脂。胶粘剂抗剪强度试验采用作者提出的推出式抗剪试验方法。在载荷幅值为50N和100N、频率为1Hz、循环次数为10万次的条件下，采用脉动疲劳试验进行试件为带底空腔的粘接耐久性试验，然后通过测量边际泄漏来评价粘接耐久性。主要研究结果如下：在各类试件中，LCT树脂的粘接强度均高于CCT树脂。I型和II型（牙本质）的粘接强度相似，因此很难用树脂标签肯定牙本质小管的锚定作用。它们的强度比IV型（牙釉质）低得多。III型（牙釉质/牙本质）的强度介于I型和iv型之间。III型试样的SEM照片显示，牙本质层粘结界面出现脱粘现象。在脉动试验后的牙釉质/牙本质试样中，验证了边缘渗漏，因此，反复加载似乎导致了边缘部分的脱粘。在复合树脂/牙釉质的粘接界面上也观察到脱粘现象。这种剪切试验方法对于评价牙科用复合树脂的粘接性能是有用的。

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.