根管预备、充填及纤维桩的预备对根管壁微裂产生的影响

The effect of root canal preparation,filling and fiber post preparation on the production of microcracks in the root canal wall

目的研究根管预备、充填及纤维桩预备对根管壁微裂产生的影响。方法收集150颗离体前磨牙,并随机分为四个大组[1组(n=10)、2组(n=20)、3组(n=40)、4组(n=80)]及15个小组(1组,2组25#、2组40#,3组A25#、3组B25#、3组A40#、3组B40#,4组AX25#、4组AX40#、4组AT25#、4组AT40#、4组BX25#、4组BX40#、4组BT25#、4组BT40#,n=10)。1组:即对照组,不进行预备;2组:均分为两组,一组预备至WaveOne25#,另一组预备则预备至40#;3组:将样本与2组一样进行分组预备,之后进一步分为2个小组,进行冷牙胶侧压充填(A)及热牙胶连续波充填(B);4组:将样本与3组一样进行分组预备及充填,之后将不同方法充填后的样本进一步分为2小组进行RelyXTM(X)和RTD(T)纤维桩预备。将所有的样本从距离根尖3、5、7 mm处垂直于牙体长轴截断,在显微镜下观察微裂发生情况,并进行比较分析。结果1组及2组中均并未有裂纹存在。充填后,3组A与3组B的裂纹数目比较差异无统计学意义(P>0.05)。置入纤维桩后,4组A的牙本质裂纹明显较4组B多,且差异具有统计学意义(22/120 VS 10/120,P<0.05)。在与根尖距离7 mm处,相较于RelyXTM纤维桩,RTD纤维桩预备后牙本质产生更多裂纹,差异具有统计学意义(9/120 VS 23/120,P<0.05)。4组的裂纹总发生率高于1组、2组、3组(P<0.05),说明纤维桩置入后,牙本质裂纹较仅进行牙体预备和充填明显增多。结论纤维桩的预备主要导致根管壁裂纹的产生,冷侧压充填后进行纤维桩预备比热牙胶充填后进行桩体预备更容易产生根管壁裂纹。

Objective To study the effect of root canal preparation,filling and fiber post preparation on the production of microcracks in the root canal wall.Methods 150 isolated premolars were collected and randomly divided into 4 large groups[Group 1(n=10),Group 2(n=20),Group 3(n=40),Group 4(n=80)]and 15 small groups(Group 1,Group 225#,Group 240#,Group 3 A25#,Group 3 B25#,Group 3 A40#,Group 3 B40#,Group 4 AX25#,Group 4 AX40#,Group 4 AT25#,Group 4 AT40#,Group 4 BX25#,Group 4 BX40#,Group 4 BT25#,Group 4 BT40#,n=10).Group 1:that was,control group,no preparation;Group 2:divided into two groups,one group prepared to WaveOne25#,the other group prepared to 40#;Group 3:the samples were prepared in the same group as Group 2,and then further divided into 2 groups for cold dental glue side pressure filling(A)and hot dental glue continuous wave filling(B);Group 4:the samples were grouped and prepared and filled as in Group 3,and after that the samples were further divided into 2 groups for RelyXTM(X)and RTD(T)fiber post preparation after filling by different methods.All the samples were truncated perpendicular to the long axis of the tooth at 3,5,and 7 mm from the root apex,and the occurrence of microfracture was observed under the microscope and analyzed comparatively.Results No cracks were observed in Group 1 and Group 2.After filling,there was no statistically significant difference in the number of cracks between Group 3A and Group 3B(P>0.05).After fiber post application,Group 4A had significantly more dentin cracks than that in Group 4B,and the difference was statistically significant(22/120 VS 10/120,P<0.05).At a distance of 7 mm from the root apex,more cracks were produced in the dentin after RTD fiber post preparation compared to RelyXTM fiber post,and the difference was statistically significant(9/120 VS 23/120,P<0.05).The total incidence of cracks in Group 4 was higher than that in Group 1,Group 2,and Group 3(P<0.05),suggesting that dentin cracks were significantly more frequent after fiber post placement compared to dental preparation and filling.Conclusion Fiber post preparation mainly contributes to the dentin crack formation.Fiber post preparation after cold lateral compression filling is more likely to result in root canal wall cracks than pile preparation after warm gutta-percha filling.