The effect of root canal preparation,filling and fiber post preparation on the production of microcracks in the root canal wall
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 2 25#,Group 2 40#,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.
Dentin cracksFiber post preparationRoot canal preparationRoot canal filling
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