Which Factors Affect the Completion and Publication of Dental Implant Trials?

Clinical decision making in implant dentistry may be vulnerable to industry influence. The purpose of this study was to identify factors associated with the completion and publication of implant trials.

This was a cross-sectional study of dental implant trials registered with ClinicalTrials.gov. The predictor variables were composed of a set of study characteristics including study design (investigational or observational), topic, sample size (≤50 or >50 participants), investigator specialty (periodontics, oral-maxillofacial surgery, prosthodontics, general/implantology, or other), study site (United States or international), and industry funding (yes or no). The outcome variables were time to study completion and time to publication. Reverse Kaplan-Meier analyses were used to determine time-to-event probabilities, and Cox proportional hazards models were used to identify factors associated with study completion and publication.

A total of 317 trials were included in the final sample. The median trial duration was 2.3 years, and the median time from completion to publication was 1.9 years. Compared with periodontist-led trials, oral and maxillofacial surgeon-led trials had greater success with publication (publication rate, 73.0% vs 54.4%; P = .01) but were less likely to be conducted in the United States (US site present, 8.8% vs 46.0%; P < .01). Trials that received industry funding were able to extend their operations by an average period of 1.2 years (P < .01). The projected trial completion rate at 5 years was 78.0%, and the projected publication rate 5 years after completion was 94.0%. Multivariate Cox regression showed that both industry-funded trials (hazard ratio, 0.66; P < .01) and pharmacologic studies (hazard ratio, 1.69; P = .02) were significantly associated with the completion rate. Among completed trials, neither industry sponsorship nor any other factor influenced the publication rate over time.

Trials that were industry funded had lower rates of completion but not publication. Future efforts should explore the reasons for research waste and improve US oral and maxillofacial surgeon involvement in clinical trial research.