Stress Analysis Of Mandibular Second Premolar With Three Different Restorations

[Objectives] To investigate the stress intensity and distribution in the dentine of intact endodontically treated mandibular second premolar under three different restorations and provide the foundation for more in vitro and clinical studies and a guidance for clinical selection of restoration methods.[Materials and Methods] Four three-dimensional finite element models were constructed by the data of Spiral CT: (1) mandibular second premolar restored directly by all ceramic crown(control group); (2) fill the perforating cavity with resin material and restored with all ceramic crown; (3) cast nickel chromium(NiCr) alloy post core plus all ceramic crown restoration; (4)fiber post and resin core plus all ceramic crown restoration. Load was applied on the buccal inclined surface near the top of the buccal cusp and in the middle of the lingual inclined surface of the buccal cusp and the intensity and distribution of the maximum tensile stress and von Mises stress in the dentine were compared.[Results] When the tooth was restored with NiCr alloy post core, an obvious stress concentration area was observed in the dentine next to the top of the post; when the fiber post was used, there was little stress concentration area around the top of the post, and the stress distribution in the dentine was almost the same as the control group; no difference of the intensity and distribution of the stress was found with the control group when no post was used and the perforating cavity was just filled with resin material.[Conclusion] Compared with cast metal post, fiber post was more suitable for post-core crown restorations. In cases with sufficient coronal tooth substance, post is not absolutely necessary and just filling the perforating cavity with resin material followed by crown restoration can be one of the alternative restorations.