Oral Microbiota and Secondary Alveolar Bone Grafting Outcomes: Evidence, Mechanisms, and Research Priorities

Secondary alveolar bone grafting (SABG) restores alveolar continuity and supports tooth eruption and subsequent orthodontic movement in patients with alveolar clefts. Established determinants of outcome include surgical, anatomical, dental, and behavioral factors. The perioperative microbial environment may also be influenced by cleft-adjacent plaque retention, oronasal communication, local inflammation, and appliance-associated biofilms. This narrative review asks whether perioperative oral microbial features are associated with defined SABG complications and whether they add clinically useful prediction of graft outcomes beyond established clinical factors. Direct SABG reports are distinguished from broader cleft and mechanistic evidence. Two reports describe, respectively, an association of preoperative salivary microbial features with study-defined inflammation at the grafted site 3 months after SABG and postoperative microbial changes; partial participant overlap remains unresolved. Neither report establishes a causal role for oral microbiota in SABG complications or validates microbial features as predictors of long-term bone outcomes or graft failure. The reviewed evidence is insufficient for routine microbiome profiling, pathogen-directed or antifungal treatment based solely on microbial findings, or microbiome-based prediction of SABG success. Without formal quality or risk-of-bias appraisal, conclusions remain provisional. Multicenter prospective studies with standardized local sampling and outcome-specific follow-up are needed to evaluate incremental prognostic value and the efficacy of microbiota-targeted interventions.