【作者】 曹琼； 张彦； 谢晓莉； 尹晓敏；

【Author】 Cao Qiong~1,Zhang Yan~2,Xie Xiao-li~2,Yin Xiao-Min~2(1:Department of Stomatology, Xiangya Second Hospital,Central South University.Changsha 410011,Hunan Province, China.2:Department of Stomatology,Xiangya Hospital,Central South University. Changsha 410008,Hunan Province,China)

【机构】 中南大学湘雅二医院口腔科； 中南大学湘雅医院口腔科；

【摘要】 目的:评估不同浓度的EDTA溶液封闭于根管内一周后对根管牙本质硬度及牙本质表面形貌影响。方法:45颗人类单根管直根前磨牙常规开髓拔髓,根尖蜡封,根管内注射5%、10%、15%、20%EDTA溶液或去离子水直至釉牙本质界,Ceivitron暂封后置于37℃恒温水浴箱内。七天后,每组各取一颗牙齿纵剖后行场发射扫描电镜扫描,并行能谱分析,余标本平均横剖为根冠、根中、根尖3部分包埋于热镶嵌材料中,经研磨抛光后使用显微硬度仪行不同深度的显微硬度测量。各组数据的比较使用Kruskal-Wallis检验,两两之间比较使用Mann-Whitney检验。结果:从根管横向和纵向比较,EDTA溶液对根管牙本质显微硬度的效果呈现随浓度增大而递减的趋势(P<0.05)。EDTA溶液有效降低距牙髓牙本质界550μm以内的牙本质显微硬度(P<0.05)。在根上、中、尖三组间,牙本质硬度的降低无显著差异(P>0.05)。随着EDTA浓度的递增,根管内壁牙本质腐蚀程度加深,表现为管周牙本质边缘变锐,胶原纤维暴露逐渐明显,开口增大,管间牙本质出现被腐蚀情况,甚至断裂,但EDTA溶液未改变根管内壁牙本质的Ca/P比值。结论:EDTA溶液封闭于根管内一周后,有效降低550μm以内的牙本质硬度,呈浓度依赖性。高浓度的EDTA溶液可以造成根管内壁牙本质较重脱矿效果,但不改变牙本质的钙磷比例。更多还原

【Abstract】 AIM:To evaluate the effect of solution with different concentrations of EDTA on the microhardness and the surface morphology of human root canal dentin after one week.METHODS:Forty-five extracted human premolars with wax fixing root tips were extirpated of pulp,injected with 5%EDTA,10%EDTA,15%EDTA,20%EDTA or deionized water to the dentino-enamel junction and obturated with Ceivitron at 37℃for one week.Five specimens of each group were used for the surface morphology of the root canal dentine using Field emission electronic microscope.Forty of them were sectioned horizontally into three segments,embedded in thermal mosaic materials and were grounded flat with silicon carbide abrasive papers.The specimens of every group(n=8)were used to determine the microhardness of different depth of root canal dentine in the coronal,middle,and apical third using Vickers microhardness tester.The data were statistically analyzed using Kruskal-Wallis test for global comparisons and the Mann-Whitney test for pairwise comparisons.RESULTS:There were significant differences between different concentrations of EDTA in the reduction of microhardness horizontally and longitudinally(P<0.05).EDTA solution reduced dentine microhardness less than 550μm from the pulp dentin border(P<0.05).ln the coronal,middle,and apical third groups,EDTA solution reduced the dentine microhardness with no significant difference(P>0.05).The morphology of root canal wall changed more apparently with high concentrations of EDTA,but Ca/P ratio kept same in different concentrations of EDTA solution.CONCLUSION:After action for one week,EDTA solution reduced dentine microhardness less than 550μm from the pulp dentin border,with concentration dependence.EDTA led to root canal wall erosion but didn’t change the ratio of calcium and phosphorus in dentine.更多还原