title: A systematic review of outcome measurements and quality of studies evaluating fixed tooth-supported restorations.
abstract: OBJECTIVE
  The purpose of this systematic review was to review clinical studies of fixed tooth-supported prostheses, and to assess the quality of evidence with an emphasis on the assessment of the reporting of outcome measurements. Multiple hypotheses were generated to compare the effect of study type on different outcome modifiers and to compare the quality of publications before and after January 2005.
  
  
  METHODS
  An electronic search was conducted using specific databases (MEDLINE via Ovid, EMBASE via Ovid, Cochrane Library) through July 2012. This was complemented by hand searching the past 10 years of issues of the Journal of Oral Rehabilitation, Journal of Prosthetic Dentistry, Journal of Prosthodontics, and the International Journal of Prosthodontics. All experimental and observational clinical studies evaluating survival, success, failure, and complications of tooth-supported extracoronal fixed partial dentures, crowns, and onlays were included. No restrictions on age or follow-up time were placed.
  
  
  RESULTS
  The electronic search generated 14,869 papers, of which 206 papers were included for full-text review. Hand-searching added 23 papers. Inclusion criteria were met by 182 papers and were included for the review. The majority were retrospective studies. Only 8 (4.4%) were randomized controlled trials. The majority of the studies measured survival and failure, and few studies recorded data on success; however, more than 60% of the studies failed to define survival, success, and failure. Many studies did not use any standardized criteria for assessment of the quality of the restorations and, when standardized criteria were used, they were modified, thereby not allowing for comparisons with other studies. There was an increase of 21.8% in the number of studies evaluating outcome measurements of all-ceramic restorations in past 8 years.
  
  
  CONCLUSIONS
  Prosthodontic literature presents with a reduced percentage of RCTs compared to other disciplines in dentistry. The overall quality of recording prosthodontic outcome measurements has not improved greatly in the past 8 years.
authors.affiliation: Prosthodontics Unit, Department of Restorative Dentistry, UCL Eastman Dental Institute, London, UK.
authors.forename: Devangkumar Rajnikant
authors.initials: DR
authors.lastname: Patel
authors.forename: Tim
authors.initials: T
authors.lastname: O'Brien
authors.forename: Aviva
authors.initials: A
authors.lastname: Petrie
authors.forename: Haralampos
authors.initials: H
authors.lastname: Petridis
mesh_terms: D003442:Crowns; D000044:Dental Abutments; D019232:Dental Restoration Failure; D003830:Denture, Partial, Fixed; D006801:Humans; D007284:Inlays; D017063:Outcome Assessment, Health Care; D016019:Survival Analysis; D016896:Treatment Outcome
keywords: Success; complications; evidence-based dentistry; standardized criteria; survival; treatment failure; treatment outcome