Teixeira Cleonice Silveira, Alfredo Edson, Thomé Luis Henrique de Camargo, Gariba-Silva Ricardo, Silva-Sousa Yara T Correa, Sousa-Neto Manoel Damião
Department of Stomatology, Dental School, University of Santa Catarina, Florianópolis, SC, Brazil.
J Appl Oral Sci. 2009 Mar-Apr;17(2):129-35. doi: 10.1590/s1678-77572009000200011.
The use of an adequate method for evaluation of the adhesion of root canal filling materials provides more reliable results to allow comparison of the materials and substantiate their clinical choice. The aims of this study were to compare the shear bond strength (SBS) test and push-out test for evaluation of the adhesion of an epoxy-based endodontic sealer (AH Plus) to dentin and gutta-percha, and to assess the failure modes on the debonded surfaces by means of scanning electron microscopy (SEM). Three groups were established (n=7): in group 1, root cylinders obtained from human canines were embedded in acrylic resin and had their canals prepared and filled with sealer; in group 2, longitudinal sections of dentin cylinders were embedded in resin with the canal surface smoothed and turned upwards; in group 3, gutta-percha cylinders were embedded in resin. Polyethylene tubes filled with sealer were positioned on the polished surface of the specimens (groups 2 and 3). The push-out test (group 1) and the SBS test (groups 2 and 3) were performed in an Instron universal testing machine running at crosshead speed of 1 mm/min. Means (+/-SD) in MPa were: G1 (8.8+/-1.13), G2 (5.9+/-1.05) and G3 (3.8+/-0.55). Statistical analysis by ANOVA and Student's t-test (alpha=0.05) revealed statistically significant differences (p<0.01) among the groups. SEM analysis showed a predominance of adhesive and mixed failures of AH Plus sealer. The tested surface affected significantly the results with the sealer reaching higher bond strength to dentin than to gutta-percha with the SBS test. The comparison of the employed methodologies showed that the SBS test produced significantly lower bond strength values than the push-out test, was skillful in determining the adhesion of AH Plus sealer to dentin and gutta-percha, and required specimens that could be easily prepared for SEM, presenting as a viable alternative for further experiments.
使用一种恰当的方法来评估根管充填材料的黏附力，能提供更可靠的结果，以便对材料进行比较并证实其临床选择的合理性。本研究的目的是比较剪切粘结强度（SBS）测试和推出测试，以评估一种环氧类根管封闭剂（AH Plus）与牙本质和牙胶的黏附力，并通过扫描电子显微镜（SEM）评估脱粘表面的失效模式。设立了三组（n = 7）：第1组，将取自人类犬齿的牙根圆柱体嵌入丙烯酸树脂中，预备根管并使用封闭剂充填；第2组，将牙本质圆柱体的纵切片嵌入树脂中，使根管表面光滑并向上；第3组，将牙胶圆柱体嵌入树脂中。将充满封闭剂的聚乙烯管放置在标本的抛光表面上（第2组和第3组）。推出测试（第1组）和SBS测试（第2组和第3组）在一台Instron万能测试机上进行，横梁速度为1毫米/分钟。以兆帕为单位的平均值（±标准差）为：第1组（8.8±1.13），第2组（5.9±1.05）和第3组（3.8±0.55）。通过方差分析和学生t检验（α = 0.05）进行的统计分析显示，各组之间存在统计学上的显著差异（p < 0.01）。SEM分析表明，AH Plus封闭剂主要出现粘结和混合失效。测试表面对结果有显著影响，在SBS测试中，封闭剂与牙本质的粘结强度高于与牙胶的粘结强度。对所采用方法的比较表明，SBS测试产生的粘结强度值明显低于推出测试，在确定AH Plus封闭剂与牙本质和牙胶的黏附力方面很有效，并且需要能够轻松制备用于SEM的标本，是进一步实验的可行替代方法。
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