Association between industry support and the reporting of study outcomes in randomized clinical trials of dental implant research from the past 20 years

Abstract

Background: Industry support is a significant funding source in implant dentistry research, not only to provide regulatory processes, but also to validate and promote products through randomized clinical trials (RCTs). However, industry funding should not affect scientific outcomes. Purpose:The aim of this study was to investigate whether there is an association between industry support for RCTs in implant dentistry and a greater chance of the reporting of positive outcomes, and whether there are other funding tendencies.Materials and Methods: Randomized clinical trials from five implant dentistry journals were reviewed. Data were extracted, and descriptive and inferential statistical analyses (α = 0.05), including bivariate and multivariable logistic regression, and Spearman's correlation were performed.Results: Two hundred eleven RCTs were included. Industry-funded and -unfunded studies presented similar outcomes, in terms of positive and negative results (p ≥ 0.05). North American and European countries received more industry funding, as did high-income countries, which showed well-established collaboration with each other. Clinical Oral Implants Research and Clinical Implant Dentistry and Related Research published 83.6% of industry-funded articles. Industry-funded studies from middle-income countries established more international collaborations with highincome countries than did unfunded studies. Citation numbers were similar for funded and unfunded studies. The chance of RCTs being industry-funded was higher for high-income (odds ratio [OR] = 3.00; 95% confidence interval [CI], 0.99-9.32; p = 0.05) and North American articles (OR = 3.40; 95% CI, 1.37-8.42; p = 0.008) than in lower-middle-income and other continents, respectively. Higher industry funding was associated with specific topics such as "surgical procedures," "prosthodontics topics," and "implant macrodesign" (OR = 4.7; 95% CI, 1.45-15.20; p = 0.010) and with the increase in numbers of institutions (OR = 1.52; 95% CI, 1.16-2.0; p = 0.002).

Translating the determinant aspects on the study design in the dental implant field

“…A similar trend was observed by our research team, which found that randomized clinical trials performed by high-income countries were more likely to be funded by industry compared with upper- and lower-middle-income countries. 14 This result is consistent with all said in this discussion since high-income countries might provide better structural and financial conditions. In addition, most reputable and well-known dental implant companies were developed in USA and Switzerland, which certainly, favor more industry support directed to both countries (Website (2020).…”

“…The findings are consistent with a recent article from our research group that reported an increasing trend in collaboration between countries over the years in the dental implant field. 14 Previous study has also demonstrated a growth in scientific production linked to increased collaboration, mainly between high-income and upper-middle/lower-income countries. 19 Further reasons for overall collaboration include rising investments, easier access to financial resources, intellectual influences, increased scientific productivity, and exchange programs.…”

“…Indeed, high-income countries hold greater resources and offer quality infrastructure, which attracts and enables a greater number of collaborations with upper-middle and low-income countries, consequently affecting scientific production. 14 , 19 , 24 …”