title: Mechanics analysis of molar tooth splitting.
abstract: A model for the splitting of teeth from wedge loading of molar cusps from a round indenting object is presented. The model is developed in two parts: first, a simple 2D fracture mechanics configuration with the wedged tooth simulated by a compact tension specimen; second, a full 3D numerical analysis using extended finite element modeling (XFEM) with an embedded crack. The result is an explicit equation for splitting load in terms of indenter radius and key tooth dimensions. Fracture experiments on extracted human molars loaded axially with metal spheres are used to quantify the splitting forces and thence to validate the model. The XFEM calculations enable the complex crack propagation, initially in the enamel coat and subsequently in the interior dentin, to be followed incrementally with increasing load. The fracture evolution is shown to be stable prior to failure, so that dentin toughness, not strength, is the controlling material parameter. Critical conditions under which tooth splitting in biological and dental settings are likely to be met, however rare, are considered.
authors.affiliation: School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, WA 6009, Australia. Electronic address: barani.amir@gmail.com.
authors.forename: Amir
authors.initials: A
authors.lastname: Barani
authors.affiliation: School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Herzl
authors.initials: H
authors.lastname: Chai
authors.affiliation: School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, WA 6009, Australia; Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Lawn
authors.affiliation: School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, WA 6009, Australia.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Bush
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D008962:Models, Theoretical; D008963:Molar / Q000473:pathology* / Q000503:physiopathology*; D014082:Tooth Fractures / Q000473:pathology* / Q000503:physiopathology*; D055815:Young Adult
keywords: Bite force; Fracture mechanics modeling; Molar cusps; Tooth splitting