Assessment of bias in methodology for randomized controlled trials published on implant dentistry

Abstract

Purpose: The purpose of this study was to assess randomized controlled trials (RCTs) published on implant dentistry over a 10-year period (1991 to 2000), based on the reporting of control of potential sources of bias in the design methodology.

Materials and methods: A MEDLINE search was conducted for RCTs using keywords dental implant and publication type randomized controlled trial. Three areas of trial methodology were assessed: (1) adequate reporting of randomization procedure, (2) blinding in assessment of outcomes, and (3) handling of subject withdrawals in data analysis. A score of 1 or 0 was assigned for each of the three potential sources of bias. Thus, the maximum quality score for an RCT is 3 and the minimum is 0.

Results: Forty-three articles met criteria for classification as RCTs. Method of randomization was explicit in 51% of the RCTs, but only 12% incorporated blinding in the assessment of outcome. Ninety-eight percent accounted for all subjects at the end of the study. Looking at overall quality scores, only 2% of RCTs adequately reported on control of bias in the three areas examined, 56% were deficient in one area, and 42% were deficient in two areas.

Conclusion: Reporting of randomization procedures and blinding in outcomes assessment for most implant RCTs was inadequate. Subject retention and documentation of subject withdrawals were adequately reported.