Effect of different carriers preventive measures in children highly infected with mutans streptococci

Antimicrobial activities of a small molecule compound II-6s against oral streptococci

Background: The side effects of present antimicrobials like chlorhexidine (CHX) and the emergence of drug resistance necessitate the development of alternative agents to control dental caries. Aim: This study developed a novel small molecule, namely II-6s, and investigated its antimicrobial activities against common oral streptococci associated with dental caries. Methods: The susceptibility of streptococci to II-6s was evaluated by the microdilution method, time-kill assay and scanning electron microscopy. The exopolysaccharides, dead/live bacteria and bacterial composition of the II-6s-treated Streptococcus mutans/Streptococcus gordonii/Streptococcus sanguinis 3-species biofilms were analyzed by confocal laser scanning microscopy, fluorescent in situ hybridization and quantitative PCR. The anti-demineralization effect and cytotoxicity of II-6s were evaluated by transverse microradiography and CCK-8 assay, respectively. Repeated exposure of S. mutans to II-6s was performed to assess if II-6s could induce drug resistance. Results: II-6s exhibited antimicrobial activity similar to CHX against S. mutans, S. gordonii and S. sanguinis and significantly inhibited exopolysaccharides production, live bacteria and the demineralizing capability of the 3-species streptococcal biofilms. Besides, II-6s showed reduced cytotoxicity relative to CHX and did not induce drug resistance in S. mutans after 15 passages. Conclusion: - II-6s may serve as a promising part of a successful caries management plan.

Topical fluoride (toothpastes, mouthrinses, gels or varnishes) for preventing dental caries in children and adolescents

BACKGROUND

Topical fluoride therapy (TFT) in the form of varnish, gel, mouthrinse or toothpaste has been used extensively as a caries-preventive intervention for over three decades.

OBJECTIVES

To determine the effectiveness and safety of fluoride varnishes, gels, mouthrinses, and toothpastes in the prevention of dental caries in children and to examine factors potentially modifying their effect.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group's Trials Register (May 2000), CENTRAL (The Cochrane Library Issue 2, 2000), MEDLINE (1966 to January 2000), plus several other databases. We handsearched journals, reference lists of articles and contacted selected authors and manufacturers.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials with blind outcome assessment, comparing fluoride varnish, gel, mouthrinse, or toothpaste with placebo or no treatment in children up to 16 years during at least 1 year. The main outcome was caries increment measured by the change in decayed, missing and filled tooth surfaces (D(M)FS).

DATA COLLECTION AND ANALYSIS

Inclusion decisions, quality assessment and data extraction were duplicated in a random sample of one third of studies, and consensus achieved by discussion or a third party. Authors were contacted for missing data. The primary measure of effect was the prevented fraction (PF) that is the difference in mean caries increments between the treatment and control groups expressed as a percentage of the mean increment in the control group. Random effects meta-analyses were performed where data could be pooled. Potential sources of heterogeneity were examined in random effects metaregression analyses.

MAIN RESULTS

There were 144 studies included. For the 133 that contributed data for meta-analysis (involving 65,169 children) the D(M)FS pooled prevented fraction estimate was 26% (95% CI, 24% to 29%; p < 0.0001). There was substantial heterogeneity, confirmed statistically (p < 0.0001), but the direction of effect was consistent. The effect of topical fluoride varied according to type of control group used, type of TFT used, mode/setting of TFT use, initial caries levels and intensity of TFT application, but was not influenced by exposure to water fluoridation or other fluoride sources. D(M)FS PF was on average 14% (95% CI, 5% to 23%; p = 0.002) higher in non-placebo controlled trials, 14% (95% CI, 2% to 26%; p = 0.25) higher in fluoride varnish trials compared with all others, and 10% (95% CI, -17% to -3%; p = 0.003) lower in trials of unsupervised home use compared with self applied supervised and operator-applied. There was a 0.7% increase in the PF per unit increase in baseline caries (95% CI, 0.2% to 1.2%; p = 0.004).

REVIEWER'S CONCLUSIONS

The benefits of topical fluorides have been firmly established on a sizeable body of evidence from randomized controlled trials. While the formal examination of sources of heterogeneity between studies has been important in the overall conclusions reached, these should be interpreted with caution. We were unable to reach definite conclusions about any adverse effects that might result from the use of topical fluorides, because data reported in the trials are scarce.

Resistance to mercury and antimicrobial agents in Streptococcus mutans isolates from human subjects in relation to exposure to dental amalgam fillings

Resistance to cefuroxime, penicillin, tetracycline, and mercury is reported for 839 Streptococcus mutans isolates from 209 human study subjects. The MICs of these drugs did not differ for isolates from one dental amalgam group and two nonamalgam subsets: a group with no known exposure to amalgam and a group whose members had their amalgam fillings removed.

In vitro susceptibility of Streptococcus mutans to chlorhexidine and six other antimicrobial agents

The susceptibility of Streptococcus mutans to chlorhexidine and to six commonly used, systemic antibacterial agents (amoxicillin, cefuroxime, penicillin, sulfamethoxazole-trimethoprim, tetracycline, and erythromycin) was studied for 424 clinical isolates from 116 children and students. The MIC of chlorhexidine for all isolates was < or = 1 micrograms/ml. No resistance to the other antimicrobial agents was detected. Although widely exposed to various antimicrobial agents, S. mutans has remained susceptible to common antimicrobial agents, most importantly to chlorhexidine.