بررسي اثر تغيير دما ناشي از محرك سرمايي روي دندان ترميم شده با پست و كورهاي متفاوت به وسيله روش اجزاي محدود

Comparison of thermal changes in restored teeth with different post and core materials: A finite element analysis

Background & Aim: If restorative materials have significant difference in thermal properties when compared with natural tooth structure, these thermal difference can produce noticeable thermal stresses, and may result in tooth fracture and leakage in the restoration which means failure in post and core treatment. The purpose of this study was to investigate the influence of thermal difference in combination of post and core materials used in endodontically treated maxillary central incisors. Materials & Methods: The finite element study model was used for this investigation. A 3-dimentional finite element model of a maxillary central incisor with a ceramic crown, a post, core, and supporting tissues were constructed. Three combinations of post, core and crown were used: 1) zirconium post/ composite core/ IPS Empress II crown 2) carbon fiber post/ composite core/ IPS Empress II crown and 3) gold post/ gold core/ IPS Empress II crown. For thermal change evaluation, the teeth were kept in 36ْ C and for cold evaluation a cold irritant at 0ْ C were applied on the outer surface of the model for seven seconds. Results: Thermal gradients in the models with zirconium and carbon fiber post and composite core were more than the model with gold post and core after seven seconds. The maximum thermal stresses were seen in restoration rather than the surrounding tissues. Conclusion: Temperature changes can produce thermal stresses and the gold post and core generated the lowest thermal stress in restoration and dentin than other non metallic restorations.