V.A.M. Gerardu

The effect of a single application of 40% chlorhexidine varnish on the numbers of salivary mutans streptococci and acidogenicity of dental plaque

The relationship between the numbers of salivary mutans streptococci and the acid production in dental plaque after a single application of the 40% chlorhexidine varnish EC40® has been studied. Thirteen healthy subjects were treated with EC40 varnish. Saliva samples were taken before and up to 12 weeks after treatment to count mutans streptococci and lactobacilli. At the same time points plaque samples were taken before and after sucrose challenge and analyzed for protein and organic acid. Suppression of salivary mutans streptococci was observed together with a reduced production of lactic acid in sucrose-challenged dental plaque in 9 subjects while inhibition of acid production without significant suppression of mutans streptococci was observed in the other 4 participants. The duration of the effects differed among the individuals but never exceeded 6 weeks. We conclude that a prolonged suppression of mutans streptococci and acid production was not achieved by a single treatment with EC40 varnish in all subjects. Moreover, reduced acidogenicity of dental plaque after chlorhexidine treatment was not necessarily predicted by suppression of mutans streptococci in saliva.

Chlorhexidine efficacy in preventing lesion formation in enamel and dentine: an in situ study

Background: Clinical studies on the caries-preventive properties of chlorhexidine mouthrinses are limited and the results are inconclusive. Aim: The aim of this study was to elucidate the contribution of a 0.2% chlorhexidine mouthrinse to the protection of enamel and dentine against demineralization. Methods: In this randomized two-treatment, two-leg study 14 individuals wearing partial prostheses were enrolled. Sound enamel and dentine specimens were placed in situ for 4 weeks. Twice daily, a mouthrinse was performed with either chlorhexidine or saline (control) depending on the experimental group the participant was allocated to. After the experimental period, plaque samples were collected from the surface of the specimens and from natural tooth surfaces to assess the organic acid production upon a sucrose challenge. The specimens were analyzed for mineral loss by transversal microradiography. Results: This study could not demonstrate a significantly better protection of enamel and dentine against demineralization by the chlorhexidine treatment compared to saline. No differences in acid production of plaque samples from the chlorhexidine-treated and control groups were observed. This result was also found for plaque samples originating from the natural tooth surfaces. Conclusion: Mouth rinsing with 0.2% chlorhexidine did not prevent demineralization of dentine and enamel in situ.

Increased Salivary Fluoride Concentrations after Post-Brush Fluoride Rinsing Not Reflected in Dental Plaque

The aim of the present study was to assess fluoride concentrations in unstimulated saliva and buccal dental plaque 6 h after an oral hygiene procedure that consisted of brushing with an AmF/SnF2 dentifrice and different post-brush rinsing protocols: expectorating the excess of dentifrice foam and rinsing with tap water, expectorating only, or rinsing with 10 ml AmF/SnF2 mouthwash. The fluoride concentrations in plaque and saliva were increased after all three experimental protocols compared to F-free periods. The increase of the fluoride concentration in saliva was more pronounced after AmF/SnF2 mouthrinse as compared to rinsing with water and expectorating the excess of dentifrice foam. Such an effect was not seen in dental plaque. It is concluded that the potentially beneficial effect of not rinsing or fluoride rinsing after tooth brushing is not reflected in an increased fluoride concentration in newly formed dental plaque 6 h after brushing.

Effects of various rinsing protocols after the use of amine fluoride/stannous fluoride toothpaste on the acid production of dental plaque and tongue flora

The aim of this clinical study was to evaluate the effect of various rinsing protocols on oral acid production 6 h after tooth brushing with an amine fluoride/stannous fluoride (AmF/SnF2) toothpaste. After a 14-day period of using F-free toothpaste, 30 participants followed three experimental protocols each, followed by F-free washout periods in a randomized crossover trial. They used AmF/SnF2 toothpaste twice daily for 1 week, and after brushing, they either rinsed with tap water, omitted the post-brush rinse, or rinsed with an AmF/SnF2 mouthwash. In the F-free washout periods, the participants brushed their teeth without further instructions. Six hours after the last brushing (± rinsing) of each period, subjects rinsed with 10 ml 10% sucrose solution for 2 min. A tongue film sample and a buccal plaque sample were taken 4 and 8 min after the sucrose challenge, respectively. Metabolic acid ions were determined by capillary electrophoresis. The results show that (1) omitting the post-brush water rinse did not reduce the production of lactic, acetic or minor acids in plaque, nor on the tongue, and that (2) the additional use of AmF/SnF2 mouthwash after brushing reduced the acid production in plaque and tongue samples for at least 6 h. The distributions of acids produced in the plaque or tongue samples were not statistically different between experimental periods. It is concluded that an increase in the antimetabolic effect of AmF/SnF2 toothpaste in between two daily brushing exercises is not achieved by omitting the post-brush water rinse. The additional use of AmF/SnF2 mouthwash after brushing is effective in reducing the acid metabolism in dental plaque and tongue flora.

Effect of various rinsing protocols after use of amine fluoride/stannous fluoride toothpaste on the bacterial composition of dental plaque.

This clinical study evaluated the effect of different oral hygiene protocols on the bacterial composition of dental plaque. After a 2-week period of using fluoride-free toothpaste, 30 participants followed three 1-week experimental protocols, each followed by 2-week fluoride-free washout periods in a randomized crossover examiner-blind controlled trial. The 1-week experimental protocols comprised the use of AmF/SnF2 toothpaste twice daily, after which participants either (1) rinsed with tap water, (2) did not rinse but only spat out the toothpaste, or (3) rinsed with an AmF/SnF2 mouthwash. In the fluoride-free washout periods, the participants brushed their teeth with fluoride-free toothpaste without further instructions. Six hours after the last brushing (± rinsing) of each period, buccal plaque samples in the upper molar region were taken. The microbiota composition of the plaque samples was analyzed by checkerboard DNA:DNA hybridization. A statistically significant reduction was found in the total amount of DNA of the 39 major plaque species measured, and in the proportions of some acid-producing bacterial strains after the period having used the AmF/SnF2 toothpaste + AmF/SnF2 mouthrinsing. The results indicate that using the AmF/SnF2 toothpaste and rinse combination could result in plaque of lower cariogenicity.