title: Bone loading pattern around implants in average and atrophic edentulous maxillae: a finite-element analysis.
abstract: BACKGROUND
  Oral implants placed in the maxilla, especially the posterior region, have a lower success rate than those placed in the mandible. Poor bone quantity and quality have been suggested as a reason for this differential success rate.
  
  
  OBJECTIVE
  The purpose of this study was, therefore, to evaluate stress and strain distributions around loaded implants in the normal and atrophic maxilla by finite-element (FE) analyses.
  
  
  METHODS
  FE models of a solitary implant were generated to determine stresses and strains in the bone adjacent to the implant surface under loading conditions.
  
  
  METHODS
  Different bony situations and implant lengths were used in a FE model. Static loads were applied axially and the resulting stresses and strains calculated.
  
  
  RESULTS
  Bone quality and quantity play a major role in decreasing bone strains adjacent to the implant surface under loading. It was found that stresses were more homogeneously distributed when more spongy bone was present. Decreased bone height was found to have less pronounced effects on strain and stress alterations than poor bone quality. Atrophic bony dimensions in combination with poor bone quality were associated with surface strains exceeding physiological levels (> 6,000 microstrains).
  
  
  CONCLUSIONS
  Our investigation indicates that supraphysiological bone strains adjacent to the implant surface should be expected under mechanical loading in the atrophic maxilla.
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University of Münster, Germany. ulmeyer@uni-muenster.de
authors.forename: U
authors.initials: U
authors.lastname: Meyer
authors.forename: D
authors.initials: D
authors.lastname: Vollmer
authors.forename: C
authors.initials: C
authors.lastname: Runte
authors.forename: C
authors.initials: C
authors.lastname: Bourauel
authors.forename: U
authors.initials: U
authors.lastname: Joos
mesh_terms: D000539:Alveolar Process / Q000473:pathology / Q000503:physiopathology; D001284:Atrophy; D015519:Bone Density; D003198:Computer Simulation; D015921:Dental Implants; D017267:Dental Prosthesis Design; D020342:Finite Element Analysis; D006801:Humans; D007575:Jaw, Edentulous / Q000473:pathology / Q000503:physiopathology*; D008437:Maxilla / Q000473:pathology / Q000503:physiopathology*; D008954:Models, Biological; D016348:Osseointegration; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D015921:Dental Implants