多巴胺预处理根管内壁对AH-plus糊剂粘接效果的影响

Effect of dopamine pretreatment on root canal bonding with AH⁃plus sealer

目的探讨用多巴胺预处理根管内壁对提高AH-plus糊剂与根管牙本质壁的粘接性能的效果。方法收集新鲜无龋坏、牙根无折裂、根管弯曲度<10°的单根管离体恒牙32颗,均使用旋转镍钛器械ProTaper预备至F2,分别使用1、2、3 mg/mL多巴胺溶液预处理根管24 h并分为4组(n=8):0 mg/mL多巴胺组(空白对照组)、1 mg/mL多巴胺组、2 mg/mL多巴胺组、3 mg/mL多巴胺组。用扫描电镜观察多巴胺与根管牙本质壁的结合状况;激光共聚焦扫描显微镜观察AH-plus糊剂渗透情况;以AH-plus糊剂与牙胶尖用冷牙胶侧方加压技术进行根管充填,在根中1/3及根尖1/3处切割根管,切片厚度1~2 mm,在万能试验机下进行根充物推出试验,比较各组间推出粘接强度。结果通过扫描电镜可以观察到对照组0 mg/mL多巴胺溶液处理24 h后,牙本质小管大部分呈现开放状态;1 mg/mL组,根管内壁牙本质小管表面有少量多巴胺颗粒分布疏松不均匀;2mg/mL组,可观察到大部分牙本质小管被多巴胺颗粒覆盖,且多巴胺层均匀致密;3 mg/mL组,牙本质小管管口沉积大量多巴胺颗粒,但不均匀分布。通过激光共聚焦扫描显微镜下可观察到多巴胺和AH-plus糊剂可以同时渗入牙本质小管。解剖部位与多巴胺浓度两因素交互作用对AH-plus糊剂粘接强度无显著差异(P>0.05);根管经2 mg/mL多巴胺处理后,与AH-plus糊剂粘接强度最高(P<0.05);分析不同解剖部位的糊剂粘接强度结果有显著差异(P<0.05);AH-plus糊剂粘接强度在根中1/3高于根尖1/3。结论不同多巴胺浓度处理根管内壁对AH-plus糊剂粘接效果有影响,2 mg/mL多巴胺溶液处理24 h后,AH-plus糊剂与根管内牙本质壁粘接效果较好。

Objective To observe the effect of dopamine pretreatment of the root canal on improving the bondingper formance of AH-plus sealer.Methods A total of 32 freshly isolated permanent teeth with a single canal were collected,with no caries,no fracture of roots,and a root canal curvature<10°.All sample root canals were prepared to F2 with Pro Taper rotating nickel-titanium instruments and then treated with 1 mg/m L,2 mg/m L,or 3 mg/m L dopamine solution for 24 hours and divided into 4 groups(n=8):0 mg/m L dopamine group(blank control group),1 mg/m L dopamine group,2 mg/m L dopamine group,and 3 mg/m L dopamine group.Scanning electron microscopy was used to observe the combination of dopamine and root canal dentin wall;laser confocal scanning microscopy was used to observe the penetration of AH-plus sealer;and root canal filling was performed with AH-plus sealer and gutta-percha tip using the cold gutta-percha lateral pressure technique.The root canal samples were cut horizontally at the middle and the apical thirdsections of the root with a slice thickness of 1-2 mm.The push-out test was carried out under an Instron universal test-ing machine to compare the push-out bonding strength between each group.Results Scanning electron microscopyshowed that most of the dentinal tubules were open in the control group after 0 mg/m L dopamine solution treatment for24 hours.In the 1 mg/m L group,a small number of dopamine particles on the surface of the dentin tubules in the innerwall of the root canal were loose and unevenly distributed.In the 2 mg/m L group,most of the dentinal tubules were cov-ered by dopamine particles,and the dopamine layer was uniform and dense.In the 3 mg/m L group,a large number ofdopamine particles were deposited at the mouth of the dentinal tubules,but the distribution was uneven.Dopamine andAH-plus sealer can be seen to simultaneously infiltrate into dentinal tubules under a confocal laser scanning micro-scope.The interaction of the two factors,the anatomical location and dopamine concentration,had no significant effectson the bonding strength of AH-plus sealer(P>0.05).Root canals treated with 2 mg/m L dopamine had the highest bond-ing strength in all groups(P<0.05).Analysis of the push-out test of bonding strength with AH-plus sealer at differentanatomical locations showed significant differences(P<0.05).The push-out bonding strength of the AH-plus sealer inthe middle third section of the root was higher than that in the apical third section of the root.Conclusion Differentdopamine concentrations could affect the bonding strength of AH-plus sealer in root canals.When treated with 2 mg/m Ldopamine for 24 hours,the bonding effect of AH-plus sealer in root canals was improved.