Effect of sodium hypochlorite gel on bacteria associated with periodontal disease

Abstract Objectives An adjunct in non-surgical periodontal therapy might be sodium hypochlorite (NaOCl)–based agents. The purpose of the present in vitro study was to get deeper knowledge on the influence of different parameters as time after mixing, pH, and chemical composition of an amino acid 0.475% NaOCl (AA-NaOCl) gel consisting of two components on its anti-biofilm activity. Materials and methods Six-species biofilms were cultured for 5 days, before AA-NaOCl gel was applied. In the different series, the influence of the time after mixing of the two components before application, of the concentration of NaOCl in the gel mixture, of the pH of the gel mixture, and of an exchange of the amino acid component by hyaluronic acid (HA), was analyzed. Results Mixing time point experiments showed that the AA-NaOCl gel is capable of statistically significantly reducing colony-forming unit (cfu) counts up to 30 min after mixing, but only up to 20 min after mixing the reduction was more than 2 log10 cfu. The pH experiments indicate that a reduced pH results in a reduced activity of the NaOCl formulation. NaOCl concentrations in the formulation in the range from 0.475 to 0.2% provide adequate activity on biofilms. A HA/NaOCl gel was equally active against the biofilm as the AA-NaOCl gel. Conclusion Mixing of the components should be made in a timeframe of 20 min before applications. An optimization of the composition of the NaOCl formulation might be possible and should be a topic in further in vitro studies. Clinical relevance The AA-NaOCl gel formulation can be mixed up to 20 min before application. Further, the study indicates that the composition of the NaOCl gel formulation can be optimized.