title: One-year results of maxillary overdentures supported by 2 titanium-zirconium implants - implant survival rates and radiographic outcomes.
abstract: OBJECTIVE
  To assess implant survival rates and peri-implant bone loss of 2 titanium-zirconium implants supporting maxillary overdentures at 1 year of loading.
  
  
  METHODS
  Twenty maxillary edentulous patients (5 women and 15 men) being dissatisfied with their complete dentures were included. In total, 40 diameter-reduced titanium-zirconium implants were placed in the anterior maxilla. Local guided bone regeneration (GBR) was allowed if the treatment did not compromise implant stability. Following 3 to 5 months of healing, implant-supported overdentures were inserted on two ball anchors. Implants and overdentures were assessed at 1, 2, 4, and 8 weeks after implant insertion and 2, 4, and 12 months after insertion of overdentures (baseline). Standardized radiographs were taken at implant loading and 1 year. Implant survival rates and bone loss were the primary outcomes.
  
  
  RESULTS
  Nineteen patients (1 dropout) with 38 implants were evaluated at a mean follow-up of 1.1 years (range 1.0-1.7 years). One implant failed resulting in an implant survival rate of 97.3%. There was a significant peri-implant bone loss of the implants at 1 year of function (mean, 0.7 mm, SD = 1.1 mm; median: 0.48 mm, IQR = 0.56 mm).
  
  
  CONCLUSIONS
  There was a high 1-year implant survival rate for edentulous patients receiving 2 maxillary implants and ball anchors as overdenture support. However, several implants exhibited an increased amount of bone loss of more than 2 mm. Overdentures supported by 2 maxillary implants should thus be used with caution as minimally invasive treatment for specific patients encountering problems with their upper dentures until more long-term data is available.
authors.affiliation: Department of Oral Implantology and Prosthetic Dentistry, Academic Center for Dentistry Amsterdam (ACTA), Move Research Institute, Amsterdam, The Netherlands.|Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Anja
authors.initials: A
authors.lastname: Zembic
authors.affiliation: Department of Oral Implantology and Prosthetic Dentistry, Academic Center for Dentistry Amsterdam (ACTA), Move Research Institute, Amsterdam, The Netherlands.
authors.forename: Ali
authors.initials: A
authors.lastname: Tahmaseb
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
authors.affiliation: Department of Oral Implantology and Prosthetic Dentistry, Academic Center for Dentistry Amsterdam (ACTA), Move Research Institute, Amsterdam, The Netherlands.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wismeijer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003779:Denture Design; D003828:Denture, Overlay; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000000981:diagnostic imaging / Q000534:rehabilitation; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D008875:Middle Aged; D011446:Prospective Studies; D014025:Titanium; D015040:Zirconium
chemical_list: D015040:Zirconium; D014025:Titanium
keywords: alveolar bone loss; ball anchor; bone resorption; dental implants; dental prosthesis; edentulous; implant-supported; jaw; maxilla; survival rate; titanium-zirconium