title: Implant-supported versus implant-retained distal extension mandibular partial overdentures and residual ridge resorption: a 5-year retrospective radiographic study in men.
abstract: OBJECTIVE
  This retrospective study sought to examine posterior mandibular ridge resorption under implant-supported and implant-retained distal extension partial overdentures in men at the end of a 5-year observation period.
  
  
  METHODS
  Class I mandibular partial edentulism was managed in 34 patients with removable partial overdentures that were adjunctively supported (n = 18) or retained (n = 16) via resilient attachments placed bilaterally on single implants (n = 68) in the first molar areas. Posterior Area Indices (PAI) were calculated for each patient by digitizing the traced rotational tomograms taken immediately before and after 5 years of treatment. Proportional rather than actual measurements were used in an effort to minimize errors related to magnification and distortion.
  
  
  RESULTS
  Residual ridge resorption associated with the implant-supported partial overdentures was recorded as PAI =0.012 ± 0.022; it was PAI = 0.073 ± 0.044 for the implant-retained group. Estimated average reductions in ridge heights were 0.15 and 1.03 mm for implant-supported and implant-retained partial overdentures, respectively. Multiple linear regression models demonstrated that prosthesis type, initial mandibular ridge height, and relining frequency were significantly correlated with PAI.
  
  
  CONCLUSIONS
  Implant-supported partial overdentures appear to be associated with reduced posterior mandibular alveolar ridge resorption when compared to implant-retained ones. Int J Prosthodont 2011;24:306-313.
authors.forename: Moustafa Abdou
authors.initials: MA
authors.lastname: Elsyad
authors.forename: Ahmed Ali
authors.initials: AA
authors.lastname: Habib
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging; D019094:Dental Prosthesis, Implant-Supported; D003828:Denture, Overlay; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies