In the hierarchy of evidence-based dentistry, which study design provides the highest level of evidence for evaluating treatment effectiveness?

The hierarchy of evidence in evidence-based medicine places systematic reviews and meta-analyses of RCTs at the top, followed by individual RCTs, then cohort studies, case-control studies, case series, and expert opinion at the bottom. Randomized Controlled Trials (RCTs) are considered the gold standard for evaluating treatment effectiveness because random allocation minimizes selection bias and confounding variables, allowing causal inferences. Among individual study designs (excluding systematic reviews), RCTs provide the highest quality evidence.