Peri-implantitis debridement: less than 1 mm cleaned in this SEM cohort

The first objective in treating peri-implantitis is simple to state and brutally hard to achieve: remove the biofilm from the implant surface. But how much of the surface does conventional decontamination actually reach? This study answers with hard physical measurement rather than assumption. Implants removed from patients — for biological or mechanical reasons, including bone loss into the apical third, fixture tearing, or fracture — were examined under scanning electron microscopy. The authors measured the "contaminant-free zone": the band of surface, between the apical edge of remaining biofilm and the first bone-to-implant contact, that decontamination had genuinely cleaned.

Forty-nine implants from thirty-nine patients were analysed. The mean contaminant-free zone measured just 0.66 ± 0.67 mm, with a range from zero to 3.0 mm. Crucially, no patient or implant variable moved the needle: sex, age, diabetes, smoking, implant location, fixture type, length, reason for removal, prosthetic type — none significantly affected how much surface ended up clean. The width stayed stubbornly under a millimetre regardless.

The conclusion is a direct instruction for the operating field. If decontamination reliably cleans less than one millimetre of surface, then biofilm removal during peri-implantitis treatment cannot be left to broad strokes. Every exposed fixture surface above the remaining marginal bone needs precise, deliberate, mechanical debridement — there is no margin for the assumption that a quick pass has done the job. The study is observational and limited to explanted fixtures, so it describes what decontamination has historically achieved rather than what an ideal protocol could reach. But as a reality check on the gap between intention and result at the implant surface, it is sobering and clinically actionable.