Repeated local delivery of hyaluronic acid gel as adjunctive treatment of residual pockets in periodontitis patients undergoing supportive periodontal care. A randomized controlled clinical trial

Objectives To assess the effect of hyaluronic acid (HyA) application as adjunct to re-instrumentation of residual pockets in patients undergoing regular supportive periodontal care (SPC). Methods Chronic periodontitis patients (stage III and IV, grade B and C) with 4 interproximal residual pockets were randomly assigned to the test (HyA gel) or control (saline) group. After subgingival instrumentation, test or control substance was applied subgingivally, then daily supragingivally for 3 months, and if required a second time after subgingival re-instrumentation after 3 months. Clinical and patient reported outcome parameters were recorded every 3 months for 12 months. Pocket closure [probing pocket depth (PPD) ≤ 4mm with absence of bleeding on probing (BoP) at PPD = 4mm] was the main outcome parameter. Results Fifty-six patients (221 experimental sites) were analysed. Pocket closure was achieved in 56.8 and 46.6% of the experimental sites in the test and control group, respectively (p > 0.05), while median PPD and PPD distribution (< 5mm/5mm/ > 5mm) differed significantly between groups in favour of the test group, at 12 months. Further, significantly fewer sites in the HyA group required re-instrumentation at 3 months, and sites in the HyA group showed a tendency for lower odds to remain diseased compared to the control group (OR 0.48, 95%CI 0.22–1.06). The odds for a site to remain diseased after 12 months increased significantly in the presence of plaque (OR 7.94, 95%CI 4.12–15.28), but in general, decreased significantly over time (OR 0.48, 95%CI 0.28–0.81). Conclusion Re-instrumentation of residual pockets in SPC patients, per se , leads to a significant increase in pocket closure over time; this was impeded by poor plaque control. Repeated local application of HyA results in fewer sites requiring re-instrumentation and might slightly improve the rate of pocket closure. (clinicaltrials.gov registration nr. NCT04792541). Clinical relevance HyA gel is easy to apply, well accepted by patients, and may have some positive effect in terms of fewer sites requiring re-instrumentation at 3 months and higher pocket closure rate at 12 months.