Effect of an intensified treatment with 40% chlorhexidine varnish on plaque acidogenicity

Previous work showed that a single application of 40% chlorhexidine varnish, EC40, reduced plaque acidogenicity upon sucrose challenge during less than 3 weeks. It was questioned whether lactic acid production could be reduced significantly longer when the treatment was intensified. Therefore, the effects of three consecutive EC40 applications on plaque acidogenicity were evaluated. Nine subjects who participated in the previous study received three full mouth EC40 applications within 1 week. Before the first application and up to 9 weeks after the third application, plaque samples were taken after a 10% sucrose rinse and analyzed for organic acids with capillary electrophoresis. At baseline, the mean provoked lactic acid concentration was 1.64 (+/-0.69) micromol/mg protein. At the first and seventh day after the third application, there was too little plaque to measure acid concentrations. At 2 weeks after the third application, lactic acid concentrations were significantly reduced (p < 0.05). The acid concentrations 3 weeks after the third application (1.61 (+/-0.99) micromol/mg protein) did not differ from the values at baseline (paired T test, p > 0.05). We conclude that a triple 40% chlorhexidine varnish treatment did not affect plaque acidogenicity for more than 3 weeks. From comparison with a previous study, we conclude that the triple treatment with EC40 within 1 week was not more effective in reducing plaque acidogenicity than the single one.