Systematic review of outcome measurements and reference group(s) to evaluate and compare implant success and failure

Background: There is a lack of consensus on measures to assess implant performance in clinical research. Objectives: To investigate the outcomes measures and reference groups employed to evaluate and compare implant success and failure. Data Sources: MEDLINE (OVID) and Web of Science with searching reference lists of included papers. Study Eligibility Criteria: Inclusion: root form, titanium implants in dentate or edentulous individuals. Longitudinal studies reporting survival or success outcomes on at least 20 participants >= mean 5 years. Study Appraisal and Synthesis Methods: Descriptive statistics. Results: Two- hundred and sixteen studies were included. Implant survival was the most commonly reported primary outcome (60%) with success at 15.7%. Success constituted a wide variety of measures with little consistency. A percentage of 98.6% of studies employed the implant as the unit of analysis with little consideration of clustering within patients. The status of periodontal and general heath of study groups was unclear for more than 80% studies. The proportion of studies comprising randomized trials or using appropriate analytical methods increased from 1980 to 2011. Limitations: Considers only English language and there was no author contact. Conclusion: In view of the disparate outcome measures employed to assess dental implant performance, agreement is needed both on a core set of implant outcomes and their statistical management.