title: Treatment outcomes of fixed or removable implant-supported prostheses in the edentulous maxilla. Part II: clinical findings.
abstract: BACKGROUND
  There is a widespread belief that maxillary overdenture prostheses are associated with a higher frequency of complications and require more maintenance than fixed implant prostheses.
  
  
  OBJECTIVE
  This prospective clinical study compared the treatment outcomes of fixed and removable implant-supported restorations in the edentulous maxilla with the main emphasis on the clinician's point of view.
  
  
  METHODS
  Ten patients were treated with fixed screw-retained implant prostheses (group 1), and 10 patients were treated with removable implant-supported overdentures (group 2) in the edentulous maxilla. Recall was scheduled at 6-month intervals to investigate the prosthodontic treatment outcomes, including implant survival, prosthesis time until retreatment, and maintenance issues. Clinical parameters gingival index (GI), plaque index (PI), the clinical attachment level, and radiographic marginal bone levels measured, along with any biologic and mechanical complications were recorded.
  
  
  RESULTS
  Patients were followed over a mean period of 39 months (SD=7; group 1) and 27 months (SD=10; group 2) after implant placement. Cumulative implant survival was 97.6% for group 1 and 94.4% for group 2 after an 18-month observation period. The mean time until retreatment after prostheses insertion was 23.4 months for group 1 and 19.8 months for group 2 (n.s.). In both groups, the increase over time in the radiographically investigated bone level was found to be significant. The indices given for the mucosal health and oral hygiene status (GI and PI) were highly correlated in both groups at each recall appointment, but no significant differences were found between groups 1 and 2.
  
  
  CONCLUSIONS
  In groups 1 and 2, comparable prosthodontic treatment outcomes were achieved. The majority of mechanical complications could be managed chairside during recall visits and did not require additional appointments, so that the time and costs involved in providing maintenance were kept down.
authors.affiliation: University of Basel, Basel, Switzerland.
authors.forename: N U
authors.initials: NU
authors.lastname: Zitzmann
authors.forename: C P
authors.initials: CP
authors.lastname: Marinello
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging; D003774:Dental Plaque Index; D019094:Dental Prosthesis, Implant-Supported / Q000191:economics; D019232:Dental Restoration Failure; D003779:Denture Design / Q000191:economics; D003827:Denture, Complete, Upper / Q000191:economics; D003828:Denture, Overlay / Q000191:economics; D005260:Female; D005500:Follow-Up Studies; D017048:Health Care Costs; D006304:Health Status; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation*; D008297:Male; D008437:Maxilla; D009909:Oral Health; D009910:Oral Hygiene; D010512:Periodontal Index; D010513:Periodontal Ligament / Q000473:pathology; D011446:Prospective Studies; D011859:Radiography; D019233:Retreatment; D013223:Statistics as Topic; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome