Abstract
Comparison of thermal changes in restored teeth with different post and core materials: A finite element analysis
Dr. Geramipanah F.,1 Dr. Nokar S.,2 Dr. Shafiee A.,3 Dr. Asadi G.4Â
1Associate professor, Department of Prosthodontics, Faculty of Dentistry, Tehran University / Medical Sciences. Tehran, Iran. 2Assistant Professor, Department of Prosthodontics and member of Dental Research Center, Faculty of Dentistry, Tehran University / Medical Sciences. Tehran, Iran. 3Assistant Professor, Department of Geotechnique and Soil mechanics, International Institute of Earthquake Engineering and Seismology. Tehran, Iran. 4Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Tehran University / Medical Sciences. Tehran, Iran.
(Received 31 Dec, 2007 Accepted 31 July, 2008)
Abstract
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 36Ù’ C and for cold evaluation a cold irritant at 0Ù’ 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.
Key words: Post and core - Finite element - Thermal stress - Restored tooth.
Corresponding Author: Dr. Asadi G., Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Tehran University / Medical Sciences. Tehran, Iran.
e.mail: asadigla@sina.tums.ac.ir