title: Effect of two designs of implant-supported overdentures on peri-implant and posterior mandibular bone resorptions: a 5-year prospective radiographic study.
abstract: OBJECTIVE
  The aim of this study was to evaluate and compare the effect of two designs of implant-supported overdentures on peri-implant and posterior mandibular bone resorptions after 5 years of follow-up.
  
  
  METHODS
  Twenty edentulous patients were randomly assigned into two equal groups: Group I (GI), patients received overdentures supported and retained by cantilevered bars on two canine implants and Group II (GII), patients received overdentures retained by straight bars on two canine implants and supported by two-first molar implants. Peri-implant vertical (VBL) and horizontal (HBLO) bone losses were assessed on periapical radiographs at the time of overdenture insertion (T0), 6 months (T6 m), 1 year (T1), 3 years (T3), and 5 years (T5) after insertion. Posterior mandibular bone resorption was evaluated using proportional measurements (posterior area index, PAI) made on panoramic radiographs at T0 and T5.
  
  
  RESULTS
  Group I recorded significant higher VBL than GII. VBL increased significantly with advance of time in both groups. Posterior implant recorded significant higher VBL than anterior implants in GII. HBLO did not differ significantly between groups or between observation times. Group I recorded significant higher PAI than GII at T5. Group, age, and initial height of the mandibular ridge were significantly correlated with PAI.
  
  
  CONCLUSIONS
  Within the limitations of this study, regarding the small sample size, it could be concluded that overdentures retained by straight bars on two canine implants and supported by two-first molar implants present a clinical advantage in terms of peri-implant and posterior mandibular bone preservation compared to overdentures supported and retained by cantilevered bars on two canine implants after 5 years.
authors.affiliation: Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
authors.forename: Moustafa A
authors.initials: MA
authors.lastname: Elsyad
authors.affiliation: Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
authors.forename: Mohammed Mahmoud
authors.initials: MM
authors.lastname: Alokda
authors.affiliation: Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
authors.forename: Ashraf Anwer
authors.initials: AA
authors.lastname: Gebreel
authors.affiliation: Oral Surgery, Faculty of Dentistry, Mansoura university, Mansoura, Egypt.
authors.forename: Nelly Ibrahim
authors.initials: NI
authors.lastname: Hammouda
authors.affiliation: Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
authors.forename: Ahmed Ali
authors.initials: AA
authors.lastname: Habib
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging* / Q000453:epidemiology; D000069343:Bone-Implant Interface; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003828:Denture, Overlay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011446:Prospective Studies; D013997:Time Factors
keywords: bone; implant; overdentures; resorption; supported