Antibiotics add half a millimetre in peri-implantitis — local beats systemic

When mechanical debridement is not enough in peri-implantitis, do antibiotics earn their place? This systematic review and meta-analysis pooled 22 randomized controlled trials comparing mechanical debridement plus antibiotics against debridement with non-antibiotic adjuncts or none, assessing bone level, bleeding on probing (BOP), probing pocket depth (PPD), clinical attachment level (CAL) and plaque indices.

Adjunctive antibiotics produced statistically significant but clinically modest gains: PPD improved by about 0.69 mm (95% CI -1.04 to -0.33), CAL by about 0.55 mm, with reductions in BOP and plaque score as well. In the cleanest subgroup (debridement plus antibiotics vs debridement alone), the CAL gain was 0.84 mm and plaque reduction likewise significant. Route of administration mattered less than expected for pockets: local and systemic antibiotics reduced PPD comparably (about -0.68 vs -0.70 mm, no significant difference), but for plaque control the local route clearly outperformed the systemic one. Heterogeneity was high in most analyses (I2 often above 90%), so the pooled estimates should be read as a direction of effect rather than precise values.

The practical reading is sober. Antibiotics add a real but small increment over mechanical debridement, on the order of half a millimetre to a millimetre of PPD or CAL. That increment must be weighed against antimicrobial stewardship: sub-millimetre gains rarely justify systemic antibiotics, while the local route offers a comparable pocket benefit, a better effect on plaque and a smaller systemic footprint. For the clinician, the evidence supports local antibiotics as a selective adjunct in the non-surgical management of peri-implantitis, not a routine reflex, and certainly not a substitute for meticulous mechanical decontamination.