Which of the following types of research study provides the highest level of evidence-based dentistry?

Correct answer: D. Meta-analysis

• A. INCORRECT. Case-control studies are observational studies that compare patients who have a disease/outcome (cases) with those who do not (controls). While useful for identifying associations, they are subject to recall bias and confounding, placing them in the middle of the evidence hierarchy.
• B. INCORRECT. A case series describes a group of patients with a similar condition without a control group. They are descriptive and cannot establish causation. They sit near the bottom of the evidence hierarchy.
• C. INCORRECT. Editorials represent expert opinions and are considered the lowest level of evidence. They lack systematic methodology and are subject to individual bias.
• D. CORRECT. Meta-analyses sit at the top of the evidence-based dentistry (EBD) hierarchy. They systematically pool and statistically analyze data from multiple randomized controlled trials (RCTs) on the same topic, providing the largest sample size and greatest statistical power. Systematic reviews with meta-analysis provide the strongest, most reliable evidence for clinical decision-making.