title: Three-dimensional finite element analysis of the application  of attachment for obturator framework in unilateral  maxillary defect.
abstract: OBJECTIVE
  The aim of this study was to evaluate the stress on the abutment teeth and framework ina unilateral maxillary defect which was restored by an obturator retained by resin-bonded extra coronal attachment.
  
  
  METHODS
  A three-dimensional finite element model of the human unilateral maxillary defect was constructed. Traditional obturator framework with four casting circumferential clasp was established (model 1). A continuous lingual guide plane of 0.5 mm thickness on all of the remaining teeth, with Mini-SG/F attachment on the mesial surface of the central incisor was also established (model 2). The modelling and analytical processes were performed using the ANSYS technologies.
  
  
  RESULTS
  Stress was transmitted to the anterior part of the palate, with stress values being lower on the anterior teeth compared with the posteriors. The highest stress value of model 1 and model 2 was 13.1 Mpa, 19.9 Mpa respectively. Stress concentrations were found at the junction of the attachment to the lingual guide plane and the anterior part of the lingual plane.
  
  
  CONCLUSIONS
  The results of this study suggest that the application of a resin-bonded extra coronal attachment for obturator retention is in accordance with the design principles for the restorative treatment of maxillary defects.The design of the attachment framework needs to be further investigated. Benefit can be gained by splinting the abutment teeth.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Ninth People's Hospital, and Department of Mechanics, Shanghai Jiaotong University, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: T
authors.initials: T
authors.lastname: Jiao
authors.forename: Y
authors.initials: Y
authors.lastname: Tie
authors.forename: D-M
authors.initials: DM
authors.lastname: Wang
mesh_terms: D000044:Dental Abutments; D003799:Dental Stress Analysis / Q000379:methods*; D003781:Denture Retention / Q000295:instrumentation*; D020342:Finite Element Analysis; D006801:Humans; D008437:Maxilla / Q000002:abnormalities*; D019231:Tooth Preparation, Prosthodontic / Q000379:methods*