Influence of different endodontic irrigants on the push-out bond strength of an epoxy-resin based sealer and newly introduced bioceramic sealer to root dentin: An in-vitro study

Aim: The present in-vitro study evaluated the influence of different organic and inorganic root canal irrigants used during chemomechanical preparation on the push-out bond strength of an Epoxy-resin based AH Plus sealer and a Bioceramic Endosequence BC sealer. Materials and Methods: Eighty extracted permanent human mandibular single rooted premolar teeth were used and randomly assigned to four major groups [according to irrigation protocol using sodium hypochlorite (NaOCl) with MTAD (mixture of tetracycline, acid and detergent) or ethylenediaminetetraacetic acid (EDTA) or phosphoric acid or normal saline (NS) as control group]. The root canals were instrumented using rotary nickel-titanium Hyflex CM file system to size 30/0.06 taper, at the working length, as final shaping and finishing file, following different irrigation protocols, as per group allocation. The samples were further subdivided into two groups, with ten samples each (n=10), based on endodontic sealer; roots were obturated with gutta-percha and test sealers (AH-Plus or Endosequence Bioceramic sealer). The teeth were decoronated and obtained samples of eighty obturated roots of eight groups were cut to obtain 2mm thick coronal root slices (10 root section in each group), using hard tissue microtome. Bond strength of sealers was then measured by subjecting each root section to a compressive load via Instron Universal testing machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA) and Tukey’s HSD along with Bonferroni’s post-hoc test and level of significance set at a p value<0.05. Results: The highest mean push-out bond strength of 5.38 MPa for AH Plus sealer was obtained in Group 2A followed by 3.94 MPa for Endosequence BC sealer (Group 2B), when phosphoric acid was used as chelating agent. However, mean bond strength of AH Plus sealer was significantly decreased (p<0.01) to 2.30 MPa when MTAD was used as chelating agent in Group 3A as compared to other groups where EDTA (Group 1A) or phosphoric acid (Group 2A) was used. Moreover, the use of chelating agents for removal of smear layer yield significantly high mean bond strength values in different groups (Group 1, Group 2, Group 3) as compared to control group (Group 4) where only NS was used (p<0.01). Conclusion: The Bioceramic based Endosequence BC sealer and gutta-percha core combination was not superior in push-out bond strength to AH Plus and gutta-percha core combination. Moreover, use of different organic and inorganic endodontic irrigants influenced the push-out bond strength of both the sealers. Clinical Significance: In dynamic clinical situation, for longer functional viability of an endodontically treated tooth, adhesion of a sealer to root dentin is necessary to avoid its dislocation during tooth flexure and also even during operative procedures like post space preparation. Adequate measures should be undertaken while using different irrigation protocols bearing in mind that the canal irrigants used during chemomechanical preparation can affect root dentin surface, thereby influencing sealer adhesion.