Influence of residual ferrule location on stress distribution of maxillary premolar restored with post-and-core crown： a three-dimensional finite element analysis

Abstract:

Objective：To investigate the stress distribution of maxillary premolar with different residual ferrule locations after post-core crown restoration using the finite element analysis. Methods：An extracted maxillary premolar was embedded in acrylic resin block. Cone-beam CT scan and a finite element analysis software were used to establish five models of post-core crown restoration with dif－ferent residual ferrule locations（group A：teeth with a circular ferrule；group B：teeth with a complete palatal ferrule；group C：teeth with a complete buccal ferrule；group D：teeth with a complete mesial ferrule；group E：teeth with a complete distal ferrule；the height of the ferrule was 2 mm in all groups）. A load of 200 N at a 45° angle to the long axis of the tooth was applied at the top 1/3 of the lingual surface of the buccal cusp. The maximum von Mises stress and the maximum principal stress were analyzed. Results：Group C had the highest maximum von Mises stress of 64.53 MPa，while group A had the lowest maximum von Mises stress of 50.87 MPa. The maximum von Mises stresses in group B，group D，and group E were 55.31，60.61 and 59.73 MPa，respectively. The maximum principal stresses in groups A to E were 43.04，43.60，47.34，45.39 and 46.91 MPa，respectively. Conclusion：A complete ferrule can effectively prevent stress concentration at the dentinal tissue of the tooth and enhance fracture resistance of the diseased tooth. When the re－maining dentinal tissue is not sufficient，preservation of the palatal ferrule can protect the integrity of the adhesive layer，increase the fracture resistance of the adhesive layer between the dentin and resin，and thus enhance the anti-fracture ability of the diseased tooth.