title: Comparative evaluation of the impact of minimally invasive preparation vs. conventional straight-line preparation on tooth biomechanics: a finite element analysis.
abstract: Minimally invasive endodontics emphasizes preservation of a maximal amount of healthy tooth tissue. However, whether the tooth structure preserved by minimally invasive endodontics can maintain higher fracture resistance is unclear. This study aimed to compare the biomechanics on teeth after minimally invasive (MI) preparation and straight-line (SL) preparation using finite element analysis. Six finite element analysis models of a mandibular first molar were constructed and divided into two groups (MI and SL). Two loads of 250 N, one vertically stimulating the vertical masticatory force and the other given 45° to the longitudinal axis of the tooth, were applied. Stresses in the teeth were calculated and analyzed. Under both vertical and 45° loads, the greatest stresses were located at the margin of the cavities on the occlusal surfaces. The stress concentration areas of teeth with minimally invasive access cavities were smaller than those of teeth prepared with straight-line opening in coronal and cervical areas. The stress concentration points in the cervical areas increased with the increase of canal taper in the coronal third. Minimally invasive access preparation reduced the stress distribution in crown and cervical regions. A smaller taper cervical enlargement caused lower stress in the cervical region.
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Keyong
authors.initials: K
authors.lastname: Yuan
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Niu
authors.affiliation: Department of Endodontics, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xie
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Endodontics, Ninth People's Hospital, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai JiaoTong University, Shanghai, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Ma
mesh_terms: D001732:Bite Force; D020342:Finite Element Analysis; D008963:Molar; D013314:Stress, Mechanical; D014070:Tooth; D019228:Tooth Crown
keywords: finite element analysis; stress; tooth preparation