不同根管封闭剂及清洗方法对纤维桩粘接强度的影响

目的 研究不同根管封闭剂和清洗方法对纤维桩粘接强度的影响，探讨二者对纤维桩粘接强度是否存在交互影响作用。方法 48颗离体下颌前磨牙行完善根管治疗后，根据根管封闭剂随机分为两组，A组采用Endofil封闭剂（丁香酚类），B组采用AH-plus封闭剂（树脂类）。桩道预备后每组再根据根管清洗方法分为3个亚组（每组8颗）：A1、B1组采用0.9%NaCl溶液清洗；A2、B2组采用17%乙二胺四乙酸（EDTA）+5.25%NaClO+0.9%NaCl溶液清洗；A3、B3组采用17%EDTA+5.25%NaClO+0.9%NaCl溶液+超声清洗。采用RelyX^TMUnicem树脂粘接剂黏固纤维桩1周后，行薄片推出实验。对结果进行三因素方差分析及Turkey检验。采用扫描电子显微镜（SEM）观察根管内壁的超微形态。结果 6组的纤维桩粘接强度分别为A1组（7.96±2.23） MPa，A2组（9.95±2.89）MPa，A3组（18.88±3.69）MPa，B1组（11.41±3.71）MPa，B2组（14.00±4.04）MPa，B3组（19.14±3.27）MPa。三因素方差分析表明：不同的根管封闭剂与清洗方法具有交互作用（P<0.05）； B1组粘接强度大于A1组，B2组大于A2组（P<0.05），B3与A3组无明显差异（P>0.05）。SEM显示A3、B3组的根管内壁玷污层最少，牙本质小管完全开放。结论 采用0.9%NaCl溶液、17%EDTA+5.25%NaClO+0.9%NaCl溶液清洗根管时，使用丁香酚类根管封闭剂较树脂类根管封闭剂的纤维桩粘接强度降低；超声联合17%EDTA+5.25%NaClO+0.9%NaCl溶液清洗根管，两种根管封闭剂对纤维桩粘接强度的影响无明显差异。

Analysis of different endodontic sealers and strategies of root canal irrigation on the bond strength of fiber posts

Objective To evaluate the influence of eugenol-containing and resin-containing endodontic sealers on the bond strength of fiber posts using different strategies of root canal irrigation. Methods Forty-eight mandibular premolars were endodontically treated. The specimens were randomly assigned into two groups according to different endodontic sealers. Group A used Endofil (eugenol-containing endodontic sealer), and group B used AH-plus (resin-containing endodontic sealer). After post space preparation, each group was randomly assigned into three subgroups according to the strategies of root canal irrigation (eight premolars in each subgroup). Group A1 and B1:0.9%NaCl irrigation; Group A2 and B2:17% ethylene diamine tetraacetic acid (EDTA)+5.25%NaClO+0.9%NaCl irrigation; Group A3 and B3: ultrasonic agitation associated with 1 7%EDTA+5.25%NaClO+0.9%NaCl. One week after the cementation of fiber posts using RelyX^TM Unicem, a push-out test was performed to measure the bond strength of the posts. The microstructure of the root canal surface was examined under scanning electron microscope (SEM). Results The bond strengths of the six groups were as follows: A1 (7.96±2.23) MPa, A2 (9.95±2.89) MPa, A3 (18.88±3.69) MPa, B1 (11.41±3.71) MPa, B2 (14.00±4.04) MPa, and B3 (19.14±3.27) MPa. Statistical analysis revealed a significant interaction between the different endodontic sealers and the strategies of root canal irrigation (P<0.05). Lower bond strength was found in group A1 but not in group B1 (P<0.05), and the same result was revealed when comparing group A2 and B2. No significant difference was observed between group A3 and B3 (P>0.05). SEM showed that the root canal in group A3 and B3 achieved the cleanest surface with nearly all dentine tubules opened. Conclusion The eugenol-containing endodontic sealer can impair the bond strength of fiber posts compared with the resin-containing sealer when the root canal is irrigated by 0.9% NaCl or 17%EDTA+5.25%NaClO+0.9%NaCl. No difference was observed between the two sealers when using 17%EDTA+5.25% NaClO+0.9%NaCl combined with ultrasonic irrigation.