2种根管封闭剂对2种纤维桩剪切粘接强度的影响

Effects of two endodontic sealers on the bond strength of two fiber posts

目的研究2种根管封闭剂对2种纤维桩固位力的影响。方法将28颗完整离体上颌中切牙截冠、逐步后退法预备根管,按采用的根管封闭材料及纤维桩不同分为4组:Cortisomol封闭剂+Matchpost纤维桩(A组),Cortisomol封闭剂+Macrolock纤维桩(B组),Guttaflow封闭剂+Matchpost纤维桩(C组),Guttaflow封闭剂+Macrolock纤维桩(D组)。纤维桩黏固后1周,牙根切成1.5 mm薄片,行薄片推出实验,并在扫描电镜下观察酸蚀处理后的桩道表面和粘接界面。结果 4组的剪切粘接强度分别为(7.06±3.22)、(9.31±3.61)、(6.90±3.13)、(9.71±3.42)MPa,B、D组剪切粘接强度显著高于A、C组(P<0.05),A组与C组、B组与D组间剪切粘接强度差异无统计学意义(P>0.05)。牙根颈、中、尖部的剪切粘接强度依次降低,差异有统计学意义(P<0.01)。扫描电镜观察:酸蚀后的桩道表面颈部较根尖部牙本质小管暴露多;颈部粘接界面树脂突的长度、数量增加,侧支交联明显。结论根管封闭剂种类对纤维桩固位无明显影响,纤维桩的表面螺纹可显著增加剪切粘接强度。根管不同区域的粘接力存在差异。

Objective To study the effects of two different endodontic sealers on the bond strength of two fiber posts cemented with adhesive resin cement.Methods Twenty-eight crownless human maxillary central incisors were prepared with the step-back technique and randomly divided into four groups according endodontic sealer and fiber： Group A,Cortisomol sealer＋Matchpost fiber post;Group B,Cortisomol sealer＋Macrolock fiber post;Group C,Guttaflow sealer＋Matchpost fiber post;Group D,Guttaflow sealer＋Macrolock fiber post.One week after fiber posts were bonded,a thin-slice push-out test was performed in a universal machine.Morphologic structure of the root canal dentin surfaces etched and the adhesive interfaces were examined by scanning electron microscopy（SEM）.Results The bond strengths of 4 groups were（7.06±3.22）,（9.31±3.61）,（6.90±3.13）,（9.71±3.42） MPa.The bond strengths of group B and D were significantly higher than that of group A and C（P0.05）.There was no significant difference between group A and C,group B and D（P0.05）.The cervical third had the highest mean push-out bond strength,next to middle third and apical third（P0.01）.SEM showed that larger numbers of the dentin tubules were open after the root canals were etched and penetration of resin tags into the dentinal tubules increased in the coronal root region when compared with the apical root region.Conclusion The shear bond strength doesn＇t have relationship with endodontic sealers.The serration significantly increases the retention of fiber post.The bond strengths are different at the three root segment sites.