title: Residual ridge resorption in the edentulous maxilla in patients with implant-supported mandibular overdentures: an 8-year retrospective study.
abstract: OBJECTIVE
  This retrospective study radiologically investigated alveolar bone resorption in the edentulous maxilla in patients with implant-supported mandibular overdentures.
  
  
  METHODS
  This study consisted of 35 healthy, completely edentulous patients with a mean age of 59.7 years. They had received two implants between the mental foramina. New bar-retained mandibular overdentures and maxillary complete dentures were fabricated. Standardized panoramic radiographs taken subsequent to loading and at annual recall visits for up to 8 years were measured for alveolar bone loss in the maxilla. Bone areas and areas of reference not subject to resorption were measured with a planimetry program. The proportional value between both was expressed as a ratio (R). Bone loss was expressed as a change in R between two time points. Differences in the resorption rate between the anterior and posterior parts of the maxilla were investigated.
  
  
  RESULTS
  Residual ridge resorption continued during the follow-up period and revealed high individual variability. With a range of 5% to 11% (median) loss in the original bone height, it was significantly (P < .031) more pronounced in the anterior than posterior maxilla (2% to 7%) from the second through eighth years. Regression analysis of the medians revealed a relatively high correlation between time and bone loss in both anterior and posterior parts of the maxilla.
  
  
  CONCLUSIONS
  The anterior anchorage of mandibular overdentures by means of two implants and an ovoid bar was associated with slightly higher resorption in the anterior than in the posterior part of the edentulous maxilla.
authors.affiliation: Department of Oral Surgery, Johannes Gutenberg University Mainz, Germany. matthiaskreisler@web.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Kreisler
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Behneke
authors.forename: Alexandra
authors.initials: A
authors.lastname: Behneke
authors.forename: Bernd
authors.initials: B
authors.lastname: d'Hoedt
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology*; D019094:Dental Prosthesis, Implant-Supported / Q000009:adverse effects*; D003781:Denture Retention / Q000295:instrumentation; D003827:Denture, Complete, Upper; D003828:Denture, Overlay / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D008439:Maxillary Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000534:rehabilitation; D011859:Radiography; D012044:Regression Analysis; D012189:Retrospective Studies; D018709:Statistics, Nonparametric