title: 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: OBJECTIVE
  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).
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: C H
authors.initials: CH
authors.lastname: Wang
authors.affiliation: Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: J K
authors.initials: JK
authors.lastname: Du
authors.affiliation: Department of Mold and Die Engineering, National Kaohsiung University of Applied Science, Kaohsiung, Taiwan.
authors.forename: H Y
authors.initials: HY
authors.lastname: Li
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: H C
authors.initials: HC
authors.lastname: Chang
authors.affiliation: Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.|School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: K K
authors.initials: KK
authors.lastname: Chen
mesh_terms: D001641:Bicuspid / Q000601:surgery*; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D011176:Post and Core Technique; D012390:Root Canal Therapy / Q000379:methods
keywords: Taguchi method; endodontically treated tooth; finite element method; post; stress analysis