title: Maxillary overdentures supported by four or six implants in the anterior region; 1-year results from a randomized controlled trial.
abstract: OBJECTIVE
  Comparing treatment outcome of four and six bar-connected implants in the anterior maxillary region to support an overdenture during a 1-year follow-up period.
  
  
  METHODS
  Fifty edentulous patients with lack of retention and stability of the upper denture, but with sufficient bone volume to place implants in the anterior maxillary region, were selected. Randomization assigned patients to either four or six implants. Implant survival, overdenture survival, clinical scores, radiographic bone height changes, and patients' satisfaction were assessed.
  
  
  RESULTS
  Forty-nine patients (one drop out) completed the 1-year follow-up. After 1 year, implant survival was 100% in the four implants group and 99.3% in the six implants group (one implant lost). Overdenture survival was 100% in both groups. Mean clinical scores were low and did not differ between groups (independent Student's t-test). Mean marginal bone resorption was 0.24 ± 0.32 mm in the four implants group and 0.25 ± 0.29 mm in the six implants group. Patients' satisfaction had improved in both groups (paired Student's t-test).
  
  
  CONCLUSIONS
  Bar-supported overdentures on four implants in the anterior maxillary region are not inferior to overdentures supported by six bar-connected implants. Implant survival was high, peri-implant conditions were healthy and patients' satisfaction had increased significantly in both groups.
authors: Department of Fixed and Removable Prosthodontics, Dental School, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. j.w.a.slot@umcg.nl
authors: Wim
authors: W
authors: Slot
authors: Gerry M
authors: GM
authors: Raghoebar
authors: Arjan
authors: A
authors: Vissink
authors: Henny J A
authors: HJ
authors: Meijer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging; D018786:Bone Substitutes / Q000627:therapeutic use; D016025:Bone Transplantation / Q000379:methods; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003774:Dental Plaque Index; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003781:Denture Retention / Q000295:instrumentation; D003827:Denture, Complete, Upper; D003828:Denture, Overlay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000627:therapeutic use; D016348:Osseointegration / Q000502:physiology; D017060:Patient Satisfaction; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D011859:Radiography; D059546:Sinus Floor Augmentation / Q000379:methods; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: C077540:Bio-Oss; D018786:Bone Substitutes; D015921:Dental Implants; D008903:Minerals