Randomized controlled trials: what are they and who needs them?

Dentistry is rapidly entering a new era of evidence-based practice, and society is demanding prevention and treatment that has been proven to be effective in terms of meaningful health outcomes. Practitioners, individual patients and the public need randomized controlled trials because they provide the highest level of scientific evidence to change clinical practice and inform public health policy. Well-designed randomized controlled trials are conceptually simple but deceptively complex to design, implement and translate into clinical practice. Randomized controlled trials are fundamentally different from observational clinical research because they randomly assign volunteers to receive test or control interventions, they are prospective and the success of the test intervention is based on a meaningful clinical outcome that is specified before the trial begins. To be successful, randomized controlled trials must be carefully designed and powered to answer a specific question that will be generalizable to the population under study. Randomized controlled trials can be designed to evaluate efficacy, effectiveness, superiority, equivalence or noninferiority. Prominent issues and challenges in designing and conducting randomized controlled trials include carefully defining enrollment criteria, establishing an organizational infrastructure, use of a data-coordinating center, developing a manual of procedures, obtaining informed consent, recruiting and ensuring the safety of volunteer subjects, ensuring data quality, analysis and publication of trial outcomes, and translating results into clinical practice.