Trends in Clinical Trial Registration in Dentistry: An Analysis of Registered Clinical Trials in the Clinical Research Information Service from 2013 to 2021 in South Korea

The Clinical Research Information Service (CRIS) in South Korea provides a clinical trial registry platform in which all clinical trials should be mandatorily and prospectively registered. However, to date, the registration status of clinical trials in the field of dentistry has not been investigated. Therefore, this study aimed to provide an overview of the methodological design and trends of the registered clinical trials over a period of nine years. Information about registered clinical trials in the field of dentistry from the CRIS was comprehensively collected from 2013 to 2021. The details assessed from the collected trials include: type of sponsors, recruitment status, study design, randomization, allocation concealment, single or multi-centric, retrospective or prospective registration, and publication status. A total of 65 registered clinical trials were identified. The number of clinical trials in dentistry in South Korea was found to be less; however, an increasing trend was observed in the recent three years. A majority of the trials were interventional (81.5%), single-centered (86.2%), and conducted on patients (81.5%) and in private hospitals (55.4%). A considerable number of trials had an unclear phase, were retrospectively registered, and rarely published. Regarding the quality, most trials have inadequately reported the method of randomization and allocation concealment. The number of clinical trials in dentistry is still low in South Korea, and most of them were registered retrospectively. A poor-quality reporting of methods at several specific areas was observed. It is necessary for dental investigators to raise awareness of the need to register clinical trials.