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

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.