Perioperative Antimicrobial Prophylaxis for Invasive Dental Procedures: A Systematic Review and Random-Effects Meta-Analysis of Randomized and Placebo-Controlled Studies

Prophylactic antimicrobials are frequently administered before invasive dental procedures (including implant placement and extractions) to reduce early infectious complications and procedure-related bacteremia; however, clinical benefit remains debated and must be balanced against ecological disruption and antimicrobial resistance. Evidence from experimental work indicates that even a single prophylactic dose of amoxicillin may transiently perturb the oral microbiome and select resistant strains.<i> </i>A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review was conducted. PubMed, Embase, and Cochrane databases were searched. <i>S</i>creening identified 10 randomized placebo-controlled/comparator trials (486 records; 289 duplicates removed; 197 screened; 72 full texts reviewed) for qualitative synthesis and meta-analysis. Included studies evaluated perioperative prophylaxis (systemic antibiotics and/or local antiseptic prophylaxis) versus placebo or no prophylaxis in invasive dental procedures. Outcomes were harmonized across studies as early procedure-related infectious outcomes and/or bacteremia-related endpoints, with secondary assessment of postoperative morbidity indicators (e.g., pain/analgesic use where available). Meta-analysis was performed in Review Manager (RevMan) version 5.4 (2020; The Cochrane Collaboration, London, United Kingdom), using an inverse-variance random-effects model. Across all invasive dental procedures (~1,950 participants pooled), prophylaxis did not demonstrate a statistically significant overall reduction in the primary pooled endpoint (MD -0.12, 95%CI -0.31 to 0.07; random-effects; I² ≈ 99%). In the dental-surgery subgroup, the pooled effect similarly crossed the null (MD -0.17, 95%CI -0.45 to 0.11; I² ≈ 99%). Individual trials showed marked reductions in post-extraction bacteremia surrogates with chlorhexidine mouthwash prophylaxis and with intravenous amoxicillin-clavulanate in extraction settings, whereas in uncomplicated extractions among well-controlled type 2 diabetes, antibiotics did not reduce postoperative complications and were associated with greater analgesic consumption. Implant trials reported low event rates and did not consistently demonstrate clinically meaningful superiority of routine prophylaxis. Funnel plot inspection suggested possible small-study effects influenced by outliers, but interpretation was constrained by extreme between-study heterogeneity.<i> </i>In this pooled analysis of randomized and placebo-controlled studies spanning heterogeneous invasive dental procedures, routine prophylactic antimicrobial strategies did not yield a consistent overall benefit on early infectious/bacteremia-related outcomes, and secondary postoperative morbidity outcomes showed no clear improvement. In parallel, microbiological evidence indicates that single-dose prophylaxis can promote short-term ecological disturbance and selection of resistant oral flora. Future trials should standardize endpoints (distinguishing clinical infection/implant failure from surrogate bacteremia measures), stratify by baseline risk, and prioritize antimicrobial stewardship to identify the limited patient subsets most likely to benefit.