Industry sponsorship bias in clinical trials in implant dentistry: Systematic review and meta-regression.

Aim: Industry sponsorship might distort the conduct and findings of studies in a large range of medical disciplines. The objective of this study was to assess whether industry sponsorship bias is present in randomized controlled trials (RCTs) on dental implants.

Material And Methods: Two databases were searched (MEDLINE; Web of Science) to identify RCTs published between 1996 and 2016 assessing different implant systems, components or techniques, such as implant-abutment connections, geometries, surfaces, loading protocols or regions of placement. Studies' sponsorship status was classified as unclear, non-sponsored or sponsored. Our outcome was marginal bone loss per year (MBL/year) of follow-up. Random-effects meta-analysis of MBL/year with subgroup analysis according to sponsorship status was performed. Moreover, multivariable stepwise-selection meta-regression was performed to assess whether sponsorship status, among other covariates, was associated with MBL/year.

Results: One hundred and two RCTs (4,775 patients, 8,806 implants) were included. Overall mean (95% confidence interval) MBL/year was 0.74 mm (95% CI 0.67/0.82). There was no significant difference in MBL/year among sponsorship categories; unclear: 0.64 (95% CI 0.37/0.91); non-sponsored: 0.65 (095% CI 0.55/0.75); and sponsored: 0.82 (95% CI 0.71/0.94).

Conclusion: Meta-regression did not demonstrate a significant association of MBL/year with sponsorship status or other covariates was found. We did not detect significant sponsorship bias in RCTs on dental implants.