Selective outcome reporting concerning antibiotics and third molar surgery.

Objectives: This study evaluates the selective outcome reporting (SOR) in clinical trials on antibiotic use in third molar surgeries. It explores how SOR may bias results and affect systematic reviews, potentially leading to misinterpretations of intervention efficacy.

Materials And Methods: A search was conducted on "ClinicalTrials.gov", "Brazilian Registry of Clinical Trials", "International Clinical Trials Registry Platform" and "European Union Clinical Trials Register" using the terms "third molar" and "antibiotics" up to December 2024. Two independent researchers selected eligible clinical trials. Data were extracted from registered protocols and corresponding publications. Discrepancies were analyzed using established criteria, and the risk of bias of published articles was assessed with Risk of Bias2.

Results: Discrepancies between protocols and publications were found in 87.5% of cases, affecting outcomes in 68.7% of studies. SOR significantly influenced results in studies with one or more discrepancies. 75% of studies assess pain post-antibiotic therapy; of those, 50% found significant results. Only 31,25% of studies showed significant reductions in trismus or edema with antibiotic use. The risk of bias varied significantly across studies.

Conclusions: The high rate of selective reporting stresses the need for transparent studies to clarify the role of antibiotics in the perioperative period. Researchers should adhere to best clinical practices, including protocol registration, accurate sample size calculations, and precision in reporting. Journals and reviewers must prioritize transparency to reduce bias and improve research quality.

Clinical Relevance: This study emphasizes the impact of SOR in clinical trials using antibiotics in third molar surgery. Clinicians should be more cautious in reading evidence based on randomized clinical trials with SORs.