Do endodontically re-treated maxillary central incisors necessitate fiber post reinforcement? [in vitro evaluation and finite element analysis]

ABSTRACT

The integrity of teeth would be affected by the thickness of remaining radicular dentin; therefore, the test hypothesis of this study was to evaluate the necessity of weakened endodontically retreated maxillary anterior teeth to be reinforced with fibre post. The radicular dentin thickness of sound teeth at coronal, middle and apical levels was measured [step 1] and compared with the remaining dentin thickness after endodontic treatment [step2], endodontic retreatment [step3] and after post hole preparation [step4] These measemeAV5 NNXC, ecsx-related with the fracture resistance of teeth submitted to corresponding steps. Finite Element Analysis [FEA] as a valid and reliable technique was used to study the stress distribution within the tooth structure in each of the previously mentioned situations. The results showed that significant reduction of radicular dentin thickness occurred after endodontic treatment in the coronal and the apical two thirds and this reduction continued insignificantly in the consequent steps On the other hand, middle one-third revealed significant reduction in endodontic retreatment at P o.o5 The fracture resistance of sound teeth [group I] was insignificantly different either with those of endodontically treated [group II] or teeth restored with post [group IV]. However, endodontically retreated teeth [group III] showed significant reduction in the fracture resistance when compared with other groups which pointed out the necessity to fibre post reinforcement. FEA showed the patterns of stress distribution within the tooth structure for each step and the similar results obtained by this technique clarify the same conclusion: