Industry-funded dental implant research is not biased in favor of positive clinical study outcomes, according to a study in the International Journal of Oral and Maxillofacial Implants (September 2011, Vol. 26:5, pp. 1024-1032).
Researchers from the University of Illinois at Chicago reviewed 1,503 articles published in five journals between 2005 and 2009 to determine whether publication bias occurs in implant-related research over time. The journals were Clinical Implant Dentistry and Related Research, Clinical Oral Implants Research, Implant Dentistry, the Journal of Oral Implantology, and the International Journal of Oral and Maxillofacial Implants.
For each article, the researchers recorded study outcome, extramural funding source, type of study, and geographic origin.
Of the articles analyzed, 1,226 (81.6%), 160 (10.6%), and 117 (7.8%) articles reported positive, negative, and neutral outcomes, respectively. In vitro studies, studies from Asia, and funded animal studies were more likely to report positive outcomes compared with others (p = 0.02, p < 0.0001, and p = 0.009, respectively).
Industry-funded studies represented the lowest frequency of positive outcomes versus studies funded by other sources, the researchers noted.
"There were a high number of implant-related studies reporting positive outcomes in the five selected journals," they wrote. "In general, funding was not associated with a positive outcome, except for animal studies."
