What happens to residual pockets during supportive periodontal therapy?

During supportive periodontal care (SPC), residual pockets represent a persistent clinical challenge and a recognised risk factor for periodontitis progression ^[1]. Repeated subgingival instrumentation of these pockets leads to significant improvements in probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing over time, and pocket closure rates increase progressively with each re-evaluation cycle ^[2]. However, poor plaque control significantly impedes pocket closure, with plaque presence shown to increase the odds of a site remaining diseased nearly eightfold ^[2].

When re-instrumentation alone is performed, outcomes can be modest, which has driven investigation into adjunctive strategies. Locally delivered antimicrobials such as chlorhexidine chip and tetracycline fibre have shown small but statistically significant additional PPD reductions of around 0.64-0.65 mm over six months compared to instrumentation alone ^[3]. Evidence for other adjuncts - including photodynamic therapy, antiseptics, hyaluronic acid, and probiotics - is currently insufficient or inconsistent to draw firm conclusions about their routine use in SPC ^[4][2]. For deep residual pockets unresponsive to repeated non-surgical care, surgical access or endoscopic-assisted debridement are options, with endoscopic re-instrumentation shown to be non-inferior to papilla preservation flap surgery in terms of CAL gain and pocket resolution at 12 months ^[5].