The Impact of Different Access Cavity Designs on the Retreatment Procedure of Single Oval Canals Using Reciprocating File Systems: An Ex-Vivo Study

This study aimed to compare the efficacy of the reciprocating system for the retreatment procedure of root canals obturated with two different sealers, through two different access designs.

A total of 40 extracted human mandibular premolars with single oval canals were selected. The samples were divided into two groups (n = 20): Group I, which had an endodontic access cavity (CEC), and Group II, which had a traditional endodontic access cavity (TEC). The samples were divided into subgroups (n = 10) according to the following sealers: Bioceramic, AH, and Saler. Retreatment was performed using the Reciproc system. Teeth were scanned with CBCT, and the percentage of residual filling was calculated. The time needed for retreatment was recorded. The ANOVA test was used for statistical analysis.

A significant difference was observed in retreatment times, with the contracted access combined with the bioceramic (BC) sealer requiring the longest time. Overall, no significant difference was found in the amount of remaining obturating material among the four groups. However, when using contracted access and the BC sealer, a significant difference was noted among the root thirds, with the coronal third showing the highest volume of residual material.

The reciprocating retreatment system was not effective in completely cleaning the canals, regardless of the access cavity design or the type of sealer used. One limitation of this study is the use of CBCT; more accurate results might have been obtained with the use of micro-CT.

The contracted access combined with the bioceramic (BC) sealer required the longest retreatment time. Residual obturating material was observed in all groups. The contracted access/BC sealer group exhibited the highest amount of remaining material in the coronal third.