title: Nonlinear finite element analyses: advances and challenges in dental applications.
abstract: OBJECTIVE
  To discuss the development and current status of application of nonlinear finite element method (FEM) in dentistry.
  
  
  METHODS
  The literature was searched for original research articles with keywords such as nonlinear, finite element analysis, and tooth/dental/implant. References were selected manually or searched from the PUBMED and MEDLINE databases through November 2007.
  
  
  METHODS
  The nonlinear problems analyzed in FEM studies were reviewed and categorized into: (A) nonlinear simulations of the periodontal ligament (PDL), (B) plastic and viscoelastic behaviors of dental materials, (C) contact phenomena in tooth-to-tooth contact, (D) contact phenomena within prosthodontic structures, and (E) interfacial mechanics between the tooth and the restoration.
  
  
  CONCLUSIONS
  The FEM in dentistry recently focused on simulation of realistic intra-oral conditions such as the nonlinear stress-strain relationship in the periodontal tissues and the contact phenomena in teeth, which could hardly be solved by the linear static model. The definition of contact area critically affects the reliability of the contact analyses, especially for implant-abutment complexes. To predict the failure risk of a bonded tooth-restoration interface, it is essential to assess the normal and shear stresses relative to the interface. The inclusion of viscoelasticity and plastic deformation to the program to account for the time-dependent, thermal sensitive, and largely deformable nature of dental materials would enhance its application. Further improvement of the nonlinear FEM solutions should be encouraged to widen the range of applications in dental and oral health science.
authors.affiliation: Department of Removable Prosthodontics, School of Dentistry, Iwate Medical University, 1-3-27 Chuodori, Morioka, Iwate 020-8580, Japan. wakabayashi.rpro@tmd.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Wakabayashi
authors.forename: M
authors.initials: M
authors.lastname: Ona
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D001696:Biomechanical Phenomena; D003764:Dental Materials / Q000737:chemistry; D017266:Dental Prosthesis; D003813:Dentistry; D020342:Finite Element Analysis; D006801:Humans; D017711:Nonlinear Dynamics; D010513:Periodontal Ligament / Q000502:physiology; D014070:Tooth / Q000502:physiology
chemical_list: D003764:Dental Materials