Effects of Various Rinsing Protocols after the Use of Amine Fluoride/Stannous Fluoride Toothpaste on the Acid Production of Dental Plaque and Tongue Flora

Effectiveness of probiotic, chlorhexidine and fluoride mouthwash against Streptococcus mutans - Randomized, single-blind, in vivo study

Aim:

To determine the short-term efficiency of probiotic, chlorhexidine, and fluoride mouthwashes on plaque Streptococcus mutans level at four periodic intervals.

Materials and Methods:

This was a single-blind, randomized control study in which each subject was tested with only one mouthwash regimen. Fifty-two healthy qualified adult patients were selected randomly for the study and were divided into the following groups: group 1- 10 ml of distilled water, group 2- 10 ml of 0.2% chlorhexidine mouthwash, group 3- 10 ml of 500 ppm F/400 ml sodium fluoride mouthwash, and group 4- 10 ml of probiotic mouthwash. Plaque samples were collected from the buccal surface of premolars and molars in the maxillary quadrant. Sampling procedure was carried out by a single examiner after 7 days, 14 days, and 30 days, respectively, after the use of the mouthwash. All the samples were subjected to microbiological analysis and statistically analyzed with one-way analysis of variance (ANOVA) and post-hoc test.

Results:

One-way ANOVA comparison among groups 2, 3, and 4 showed no statistical significance, whereas group 1 showed statistically significant difference when compared with groups 2, 3, and 4 at 7^th, 14^th, and 30^th day.

Conclusion:

Chlorhexidine, sodium fluoride, and probiotic mouthwashes reduce plaque S. mutans levels. Probiotic mouthwash is effective and equivalent to chlorhexidine and sodium fluoride mouthwashes. Thus, probiotic mouthwash can also be considered as an effective oral hygiene regimen.

Models and Role Models

Developing experimental models to understand dental caries has been the theme in our research group. Our first, the pH-cycling model, was developed to investigate the chemical reactions in enamel or dentine, which lead to dental caries. It aimed to leverage our understanding of the fluoride mode of action and was also utilized for the formulation of oral care products. In addition, we made use of intra-oral (in situ) models to study other features of the oral environment that drive the de/remineralization balance in individual patients. This model addressed basic questions, such as how enamel and dentine are affected by challenges in the oral cavity, as well as practical issues related to fluoride toothpaste efficacy. The observation that perhaps fluoride is not sufficiently potent to reduce dental caries in the present-day society triggered us to expand our knowledge in the bacterial aetiology of dental caries. For this we developed the Amsterdam Active Attachment biofilm model. Different from studies on planktonic (‘single') bacteria, this biofilm model captures bacteria in a habitat similar to dental plaque. With data from the combination of these models, it should be possible to study separate processes which together may lead to dental caries. Also products and novel agents could be evaluated that interfere with either of the processes. Having these separate models in place, a suggestion is made to design computer models to encompass the available information. Models but also role models are of the utmost importance in bringing and guiding research and researchers.

Effects of pH and lactate on hydrogen sulfide production by oral Veillonella spp

Indigenous oral bacteria in the tongue coating such as Veillonella have been identified as the main producers of hydrogen sulfide (H2S), one of the major components of oral malodor. However, there is little information on the physiological properties of H2S production by oral Veillonella such as metabolic activity and oral environmental factors which may affect H2S production. Thus, in the present study, the H2S-producing activity of growing cells, resting cells, and cell extracts of oral Veillonella species and the effects of oral environmental factors, including pH and lactate, were investigated. Type strains of Veillonella atypica, Veillonella dispar, and Veillonella parvula were used. These Veillonella species produced H2S during growth in the presence of l-cysteine. Resting cells of these bacteria produced H2S from l-cysteine, and the cell extracts showed enzymatic activity to convert l-cysteine to H2S. H2S production by resting cells was higher at pH 6 to 7 and lower at pH 5. The presence of lactate markedly increased H2S production by resting cells (4.5- to 23.7-fold), while lactate had no effect on enzymatic activity in cell extracts. In addition to H2S, ammonia was produced in cell extracts of all the strains, indicating that H2S was produced by the catalysis of cystathionine γ-lyase (EC 4.4.1.1). Serine was also produced in cell extracts of V. atypica and V. parvula, suggesting the involvement of cystathionine β-synthase lyase (EC 4.2.1.22) in these strains. This study indicates that Veillonella produce H2S from l-cysteine and that their H2S production can be regulated by oral environmental factors, namely, pH and lactate.

The anticaries effect of a food extract (shiitake) in a short-term clinical study

The main objective was to investigate whether low-molecular-weight fraction of edible mushroom shiitake extract (Lentinus edodes) possesses caries-preventive properties. The study was designed as a double-blind, three-leg, cross-over, randomized, controlled clinical trial carried out on two series of volunteers at the University of Gothenburg, and the Academic Centre for Dentistry Amsterdam. Volunteers rinsed twice daily with a solution containing low-molecular-weight fraction of edible mushroom, placebo (negative control without active ingredients), or Meridol (positive control, AmF-SnF₂) for two weeks, with a two-week washout period between each rinsing period. Changes in the acidogenicity of dental plaque before and after a sucrose challenge, shifts in microbial composition, and plaque scores were determined. Frequent rinses with shiitake reduced the metabolic activity of dental plaque. No reduction of plaque scores and no inhibition of the production of organic acids in plaque was found. Minor differences in microbial composition between test sessions were found. To conclude, the results indicate that shiitake extract has anticariogenic potential, but not to the same extent as the positive control.

The effects of fractions from shiitake mushroom on composition and cariogenicity of dental plaque microcosms in an in vitro caries model

The aim of the current study was to investigate the anticariogenic potential of the (sub)fractions obtained from the edible mushroom shiitake (Lentinula edodes) in in vitro caries model. We used a modified constant depth film fermentor (CDFF) with pooled saliva as the inoculum and bovine dentin as a substratum. The test compounds were low molecular weight fraction (MLMW) of the shiitake extract and subfractions 4 and 5 (SF4 and SF5) of this fraction. Chlorhexidine (CHX) and water served as a positive and a negative control, respectively. Dentin mineral loss was quantified (TMR), microbial shifts within the microcosms were determined (qPCR), and the acidogenicity of the microcosms was assessed (CIA). From the compounds tested, the SF4 of shiitake showed strong inhibiting effect on dentin demineralization and induced microbial shifts that could be associated with oral health. The acid producing potential was increased, suggesting uncoupling of the glycolysis of the microbiota by the exposure to SF4. In conclusion, the results suggest that SF4 of shiitake has an anticariogenic potential.

Plaque formation and lactic acid production after the use of amine fluoride/stannous fluoride mouthrinse

The aim of this study was to determine the effects of 3 wk of daily rinsing with amine fluoride/stannous fluoride (AmF/SnF(2)) mouthrinse on plaque formation at buccal and interproximal sites, and on the acid production in plaque, in a randomized clinical trial with 30 participants. The amount of plaque was scored according to Turesky's modification of the Quigley and Hein index. Plaque samples were collected, before and after sucrose rinsing, from the buccal and interproximal surfaces of upper (pre)molars at two baseline visits and on days 2 and 7 after the discontinuation of 3 wk of daily rinsing. Metabolic acid ions were determined by capillary electrophoresis. The results at baseline showed higher lactic acid concentrations in resting interproximal plaque than in buccal plaque, and a higher acid production in response to sucrose challenge in buccal plaque than in interproximal plaque. After 3 wk of use of the AmF/SnF(2) mouthrinse, no significant differences in plaque scores were observed, and the alleged reduction in acidogenicity of dental plaque was not significant on the second day after the last mouthrinse. We conclude that 3 wk of use of AmF/SnF(2) rinse once daily does not result in a reduction of plaque formation or in a reduction of sucrose metabolism in buccal and interproximal plaque after discontinuing the rinse.