Clinical and microbiological effects of a single application of sodium hypochlorite gel during subgingival re-instrumentation: a triple-blind randomized placebo-controlled clinical trial.

OBJECTIVES The aim of this study is to assess the clinical and microbiological effects of a single subgingival administration of sodium hypochlorite gel (NaOCl) and compare it with 1% chlorhexidine (CHX) gel and a placebo gel following mechanical re-instrumentation during supportive periodontal therapy (SPT). MATERIALS AND METHODS Sixty-two patients who had been treated for stage III-IV periodontitis and enrolled in SPT were included in the study based on following criteria: (1) active periodontal therapy completed at least 6 months before enrollment in the study, (2) presence of at least 4 non-adjacent sites with probing pocket depths (PPDs) ≥ 4 mm with bleeding on probing (BOP), or presence of 5-8 mm PPDs with or without BOP. All sites presenting PPD ≥ 4 mm and BOP at baseline and 3-, 6-, and 9-month follow-up timepoints were subgingivally re-instrumented with ultrasounds. Selected patients were randomly assigned into three groups and treated additionally with a single subgingival administration of NaOCl gel (group A); 1% CHX gel (group B); and placebo gel (group C). Main outcome variable was pocket closure at 12 months. Secondary outcome variables were changes in mean PPD, BOP, and clinical attachment level (CAL) along with changes in the numbers of the following five keystone bacterial pathogens: Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Prevotella intermedia (P.i.), Tannerella forsythia (T.f.), and Treponema denticola (T.d.). RESULTS At 12 months, pocket closure was obtained in 77.5% in the NaOCl treated sites. The reduction in PPD was higher with CHX than with NaOCl, although a statistically significant adjunctive effect for NaOCl (P = 0.028) was only observed in comparison with placebo only. Mean CAL improved in all groups and at all timepoints, compared to the baseline (P < 0.05). However, after 6 months, CAL gain was statistically significantly higher in the NaOCl treated group than following application of CHX (P = 0.0026). CONCLUSION In SPT patients, a single adjunctive use of a NaOCl gel may provide benefits in controlling inflammation and residual pockets. TRIAL REGISTRATION ISRCTN Registry of Clinical Trials (ISRCTN11387188). CLINICAL RELEVANCE A baseline single application of NaOCl gel in conjunction with mechanical debridement may achieve substantial pocket closure in patients enrolled in SPT; treatment time, cost, and applicability considerations should be taken into account when selecting this therapy