Factorial analysis of variables influencing mechanical characteristics of a post used to restore a root filled premolar using the finite element stress analysis combined with the Taguchi method.

ABSTRACT

AIMS: To identify the contributions of various mechanical factors related to cast posts in a root filled tooth by integration of finite element analysis and the Taguchi method. The investigated factors included post-length (Post-L), post-diameter (Post-D), ferrule height (Ferrule-H) and periodontal bone loss (Bone-H). METHODOLOGY: Three-dimensional finite element models of a mandibular premolar were developed to simulate a root filled tooth. For each investigated factor, three levels and values were selected, and based on a Taguchi orthogonal array, nine models were established. An inclination load of 100 N was applied on the buccal cusp tip, and the dentine peak von Mises stress was used as the evaluation index. RESULTS: Among the four investigated factors, Bone-H was the predominant mechanical factor, with a contribution of more than 97%. Among the other three controllable factors of post-design, Post-D was the primary contributing factor and was almost five times more substantial than the least contributing factor, Ferrule-H. CONCLUSION: Bone-H was the predominant factor influencing the stress of the dentine on a post-restored root filled tooth, followed by the Post-D, Post-L and Ferrule-H. For patients with severe periodontal bone loss, a large post-diameter is essential for endodontic post-restoration treatment.