The Effect of Ferrule/Crown Ratio and Post Length on the Applied Stress and Strain Distribution to the Endodontically Treated Maxillary Central Teeth: A Finite Element Analysis

Ramin Mosharaf; Majid Abolhasani; Amir Hossein Fathi; Ali Rajabi

doi:10.18502/fid.v20i16.12686

Ramin Mosharaf Department of Dental Prostheses, Dental Materials Research Center, Dental Sciences Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
Majid Abolhasani Department of Dental Prostheses, Dental Materials Research Center, Dental Sciences Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
Amir Hossein Fathi Department of Dental Prostheses, Dental Materials Research Center, Dental Sciences Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
Ali Rajabi Students Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran

DOI: https://doi.org/10.18502/fid.v20i16.12686

Keywords: Finite Element Analysis; Tooth Crown; Root Canal Therapy; Dental Stress Analysis

Abstract

Objectives: One of the most common methods used for the reconstruction of endodontically treated teeth is post and core and crown. Various factors such as the remaining tissue above the cutting margin (ferrule) affect the fracture resistance of teeth restored with post and core and crown. This study aimed to investigate the effect of ferrule/crown ratio (FCR) on the strength of maxillary anterior central teeth using finite element analysis.

Materials and Methods: A 3D scan of a central incisor was obtained, and the data were transferred to Mimics software. Then, a 3D model of the tooth was designed. Next, 300N load was applied at a 135° angle to the tooth model. Force was applied to the model both horizontally and vertically. Ferrule height was considered to be 5%, 10%, 15%, 20%, and 25% in the palatal surface and 50% in the buccal surface. The length of post in the model was 11, 13, and 15mm.

Results: By increasing the FCR, stress and strain distribution increased in the dental model and decreased in the post itself. As the horizontal angle of load application increased, the level of stress and strain created in the dental model increased as well. The closer the force application site to the incisal area, the higher the stress and strain would be.

Conclusion: Maximum stress was inversely correlated with FCR and post length. In ratios of 20% and higher, insignificant changes occurred in stress and strain patterns in the dental model.