Effect of film thickness of adhesive-resin cements on retentive strength of castings

第一部分研究了膜厚对铸件保持强度的影响。1. 水泥膜厚度的差异对复合型和MMA型两种水泥的固相强度没有影响。2. 实际水泥间距小于计算结果。实际与计算水泥间距之比为0.85±0.09。3. Super Bond C/B的结合强度高于Panavia 21。由表面面积换算得到的抗拉结合强度分别为10和6 Mpa。4. 多数病例均以肉眼观察牙体与骨水泥界面断裂。第二部分研究了热应力（5 ~ 58℃，1000次和10000次）下膜厚对保持强度和海洋泄漏的影响。1. 总的来说，除富士鲁特外，膜厚对保持强度的影响不明显；除Super Bond外，膜厚对边际泄漏的影响也不明显。在帕纳维亚的情况下，保持强度约为20公斤。经过1万次热应力循环后，边际泄漏量显著增加，染料渗透深度是1000次循环的3倍。3. 在超级键的情况下，最高的保持强度约为35公斤。膜厚与边际泄漏量的相关性接近显著水平，即膜厚越厚，边际泄漏量越小。4. 富士琵琶的保留强度随膜厚的增加而增加。保持强度与帕纳维亚相当。即使在1000次热应力循环后，侧壁到空腔底板也观察到相对较高的边际泄漏。5. Panavia和Fuji Lute的保留强度与边际泄漏的相关性较低，Super Bond的保留强度与边际泄漏的相关性接近显著水平。

In Part I, effect of film thickness on retentive strength of castings were studied. 1. Differences in cement film thickness did not affect the retentive strength in two kinds of cement used, composite type and MMA type. 2. Actual cement space was smaller than that determined by calculation. The ratio of Actual/ calculated cement space was 0.85±0.09. 3. Super Bond C/B exhibited higher bond strength than Panavia 21. The tensile bond strength converted from the surface area was 10 and 6 Mpa, respectively. 4. In most cases, the interfacial fracture between tooth substance and cement was observed with nakied eye.In Part II, effects of film thickness on retentive strength and marinal leakage was investigated under the thermal stress (5〜58℃, 1,000 or 10,000 times). 1. In general, effect of film thickness on retentive strength was not clearly observed except Fuji Lute, and the effect of film thickness on marginal leakage also was not clear except Super Bond, 2. In the case of Panavia, the retentive strength of approximately 20 kg was exhibited. Marginal leakage increased significantly after 10,000 cycles of thermal stress, and the dye penetration was three times deeper compared that of 1,000 cycle. 3. In the case of Super bond, the highest retentive strength of approximately 35 kg was exerted. The correlation between the film thickness and marginal leakage was close to the significant level, that is, the thicker the film thickness, the lesser the marginal leakage. 4. In the case of Fuji Lute, the retentive strength increased in accordance with the film thickness. The retentive strength was comparative to that of Panavia. Relatively higher marginal leakage was observed beyond the side wall to the cavity floor even after 1,000 cycles of thermal stress. 5. Correlation between the retentive strength and marginal leakage was low for Panavia and Fuji Lute, and close to significant level for Super Bond.