title: Finite element analysis of a transmandibular implant.
abstract: Finite element analysis (FEA) was used to study the influence of bony height and baseplate effect on the transmandibular implant (TMI). FEA was used to assess the stress distribution in the mandible, with and without a baseplate. Forces were applied to the center of a bar space. The von Mises stress (SEQV) was displayed in bone, and shear stress also was measured. Tensile stress was always seen at the so-called saddle area; compressive stress was seen at the inferior border. Tensile strain at the saddle area of a 6-mm height mandible is always 9.1 times greater (corresponding to more SEQV) than that of an 18-mm mandible. At same bone heights, saddle area stresses are similar with or without a baseplate. However, stress at the lateral transossseous post interface with bone was significantly different between different bone height groups. Shear stress around the lateral transossseous post was smaller than does the SEQV of the same site. Decreased bone height dramatically increases stress at the saddle area independent of the baseplate presence. These data suggest that bone apposition is found in the severely atrophic mandibles. Thus, there is no need for a baseplate in a slight to mild atrophic mandible.
authors.affiliation: Division of Reconstructive Surgery for Oral and Maxillofacial Region, Department of Tissue Regeneration, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-Dori, Niigata City 951-8514, Japan. t-nomura@sf7.so-net.ne.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nomura
authors.forename: Michael P
authors.initials: MP
authors.lastname: Powers
authors.forename: J Lawrence
authors.initials: JL
authors.lastname: Katz
authors.forename: Chikara
authors.initials: C
authors.lastname: Saito
mesh_terms: D001696:Biomechanical Phenomena; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D008341:Mandibular Prosthesis; D008422:Materials Testing; D011474:Prosthesis Design