The influence of endodontic sealer dentine penetration on fibreglass post retention

This study aimed to evaluate the influence of endodontic sealer inside dentinal tubules on the retention of fibreglass posts. One hundred eighty extracted teeth were instrumented with rotary instruments and divided into two groups (n = 90) according to their filling technique: (LC) lateral condensation and (CT) controlled technique, and subdivided into three subgroups according to the endodontic sealer used: (A) epoxy resin sealer, (B) zinc-oxide and eugenol sealer, and (C) bioceramic endodontic sealer. After root preparation, each subgroup received a fibreglass posts cemented with (1) adhesive resin cement, (2) self-adhesive resin cement, and (3) glass ionomer cement. After stored for 15 days at 37 °C and 100% humidity, the teeth were sectioned transversely into 1-mm thick slices and subjected to laser confocal scanning microscopy and push-out test. The failure mode was analyzed by stereo microscope, and scanning electron microscopy images of representative fractures were made. Although there were no significant differences in the dislocation resistance among the filling techniques (p > 0.05), the type of sealer used affected bond strengths on the cervical and middle thirds. Fibreglass posts cemented with glass ionomer cement presented higher values for the push-out test than those cemented with resin cements (p < 0.05). Mix failure modes were predominant and occurred in all experimental groups. The use of bioceramic endodontic sealer was able to reduce the bond strength, mainly when the fibreglass posts was cemented by resin cement.