Abstract:
Clinically, endodontically treated teeth with thin root canal wall or flared root canal is a result of carious extension, secondary caries, pin removal procedure, etc. The prognosis for this problem has been unpredictable. Recently, there have been some literatures which introduced the techniques of reinforcing the weaken root, nevertheless, suitable restorative procedures are still controversial and information on longitudinal study has been limited. In order to find out the optimal technique, this study aimed to investigate the stress distribution in root dentin and restorative materials. The 2 dimensional finite element model of flared root canal of maxillary central incisors with ten restorative methods were performed using MSC/Nastran for Windows. Three evaluated parameters were investigated : reinforcing or unreinforcing the flared root canal, reinforcing materials (composite resin and cermet) and post materials (gold alloy type III, Ni-Cr alloy, stainless steel and carbon fiber). All materials were assumed to be homogeneous, isotropic, linear elastic and perfectly bonded between the interfaces. The results showed that maximal tensile stress in dentin were reduced in the reinforcing models. Reinforcement with composite resin provided less maximum tensile stress than that with cermet. High elastic modulus of post materials provided more maximal tensile stress and less stress concentration at flared dentin than post with low elastic modulus. From this FEA study, reinforcement of flared root canal with composite resin and carbon fiber post displayed favorable stress distribution and might be a suitable technique for rehabilitating pintooth with flared root canal