title: Mandibular overdentures supported by two or four endosseous implants: a 10-year clinical trial.
abstract: OBJECTIVE
  The aim of this 10-year clinical trial was to evaluate the treatment outcome (condition of hard and soft peri-implant tissues, patient satisfaction, surgical and prosthetic aftercare) of mandibular overdentures supported by two or four implants.
  
  
  METHODS
  Sixty edentulous patients with a mandibular height between 12 and 18 mm participated. Thirty patients were treated with an overdenture supported by two IMZ implants (group A) and 30 patients were treated with an overdenture supported by four IMZ implants (group B). Standardised clinical and radiographic parameters were evaluated 6 weeks after completion of the prosthetic treatment and after 1, 5 and 10 years of functional loading. Prosthetic and surgical aftercare was scored during the evaluation period, as well as patient satisfaction.
  
  
  RESULTS
  There were no statistically significant differences with regard to any of the studied clinical or radiographic parameters of the peri-implant tissues between the groups. In addition, no differences in satisfaction and aftercare were observed between the groups.
  
  
  CONCLUSIONS
  There is no difference in the clinical and radiographical state of patients treated with an overdenture on two or four implants during a 10-year evaluation period. Patients of both groups were evenly satisfied with their overdentures and received the same amount of aftercare. For reasons of cost-effectiveness, a two-implant overdenture is advised for patients with a Cawood classes IV-VI resorption of the mandible and complaints concerning retention and stability of the lower denture.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, Groningen, The Netherlands. h.j.a.meijer@kchir.umcg.nl
authors.forename: Henny J A
authors.initials: HJ
authors.lastname: Meijer
authors.forename: Gerry M
authors.initials: GM
authors.lastname: Raghoebar
authors.forename: Rutger H K
authors.initials: RH
authors.lastname: Batenburg
authors.forename: Anita
authors.initials: A
authors.lastname: Visser
authors.forename: Arjan
authors.initials: A
authors.lastname: Vissink
mesh_terms: D000328:Adult; D000359:Aftercare; D000368:Aged; D000369:Aged, 80 and over; D001862:Bone Resorption / Q000145:classification / Q000601:surgery; D003362:Cost-Benefit Analysis; D000044:Dental Abutments; D015921:Dental Implants / Q000191:economics; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003781:Denture Retention; D003826:Denture, Complete, Lower; D003828:Denture, Overlay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000601:surgery; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000601:surgery*; D008875:Middle Aged; D009911:Oral Hygiene Index; D017060:Patient Satisfaction; D010512:Periodontal Index; D010519:Periodontium / Q000473:pathology; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants