Is fracture resistance of endodontically treated mandibular molars restored with indirect onlay composite restorations influenced by fibre post insertion?

ObjectivesThe aim of this study was to investigate the influence of post placement on fracture resistance of endodontically treated mandibular molars restored with adhesive overlay restorations.MethodsEndodontically treated human molars with two- and one-wall cavities either underwent or did not undergo fibre post insertion within composite build-up before cementation of indirect composite onlay restorations. The specimens were thermocycled, exposed to cyclic loading, and submitted to the static fracture resistance test. Fracture loads and mode of failure were evaluated.ResultsStatistical analysis revealed that specimens with fibre posts demonstrated similar failure loads (p = 0.065) but more favourable fracture patterns compared with specimens without fibre posts. No difference was found between two- and one-wall cavities.ConclusionsWithin the limitations of this study, the insertion of fibre posts did not improve support under indirect composite overlays.Clinical significanceWhen restoring heavily broken down endodontically treated mandibular molars with an indirect overlay composite restoration, the fibre post inserted within the composite build-up do not provide any increase in fracture resistance.