Chemical agents for the control of plaque and plaque microflora: an overview

Invisible assassin coated on dental appliances for on-demand capturing and killing of cariogenic bacteria

The accumulation of microbes on long-wear artificial dental materials creates a great risk for oral diseases and causes deterioration of material properties. Therefore, smart antibacterial materials capable of resisting the colonization of microorganisms and simultaneously eliminating pathogenic bacteria as needed show outstanding superiority for the recovery of dental health, which are scarcely reported until now. Here, we present a responsive hydrogel coating as invisible assassin on clear overlay appliances target for dental caries. Taking advantage of pH-responsive carboxybetaine methacrylate-dimethylaminoethyl methacrylate copolymer P(CBMA-co-DMAEMA) and antibacterial peptides, the surface potential of hydrogel shifts positively, accompanied with the release of antibacterial peptides when pH gets lower. The hybrid hydrogel layer hence exerts antifouling property and resists bacterial adhesion in normal physiological, while captures and kills cariogenic bacteria in acidic condition. This biocompatible, transparent and stable hydrogel coating has little influence for the aesthetics and mechanical properties of bulk materials. The strategy developed here can provide reference for the design of biomedical devices in other areas.

Differences in chlorhexidine mouthrinses formulations influence the quantitative and qualitative changes in in-vitro oral biofilms

OBJECTIVE

Chlorhexidine mouthrinses are marketed in different formulations. This study aimed at investigating qualitative and quantitative changes in in-vitro multispecies oral biofilms, induced by different chlorhexidine-containing mouthrinses.

BACKGROUND DATA

Earlier studies comparing chlorhexidine mouthrinses are either clinical studies or in-vitro studies assessing the antimicrobial efficacy of the mouthrinses. However, no clear investigations are available regarding ecological impact of different chlorhexidine formulations on in-vitro multispecies oral biofilms after rinsing with different chlorhexidine formulations.

METHODS

Nine commercially available chlorhexidine mouthrinses were selected. Multispecies oral communities (14 species) were grown for 48 h in a Biostat-B Twin bioreactor. After that, they were used to develop biofilms on the surface of hydroxyapatite disks in 24-well pates for 48 h. Biofilms were then rinsed once or multiple times with the corresponding mouthrinse. Biofilms were collected before starting the rinsing experiment and every 24 h for 3 days and vitality quantitative PCR was performed. The experiment was repeated 3 independent times on 3 different days and the results were analyzed using a linear mixed model.

RESULTS

The mouthrinses provoked different effects in terms of change in total viable bacterial load (VBL), ecology, and community structure of the multispecies biofilms. There was no relation between chlorhexidine concentrations, presence, or absence of cetylpyridinium chloride and/or alcohol, and the observed effects. Some tested chlorhexidine mouthrinses (MC, HG, HH, and HI) strongly lowered the total VBL (≈10⁰⁷ Geq/ml), but disrupted biofilm symbiosis (≥40% of the biofilms communities are pathobionts). On the other hand, other tested chlorhexidine mouthrinses (MD, ME, and HF) had limited impact on total VBL (≥10¹⁰ Geq/ml), but improved the biofilm ecology and community structure (≤10% of the biofilms communities are pathobionts).

CONCLUSION

Not all chlorhexidine mouthrinses have the same effect on oral biofilms. Their effect seems to be strongly product dependent and vary according to their compositions and formulations.

Synthesis and Characterization of Montmorillonite Supported Zero-Valent Bimetallic Fe/Ni Nanoparticles for the Removal of Triclosan

As an important industrial material, triclosan is widely used in manufacturing, and similar to many materials of its kind, triclosan causes significant environmental pollution, especially water pollution. In the organic pollutant degradation field, iron nanoparticles are among the most popular catalysts and have been successfully applied in various kinds of environmental modification, but there is still plenty of room for improvement. As we will show in this study, combined with nickel, the montmorillonite-supported Fe-Ni bimetallic nano-systems gained better organic contaminant degradation ability and stability than iron nanoparticles. By means of X-ray diffraction (XRD), Brunauer- Emmett-Teller (BET) surface area analysis, Fourier transform infrared (FTIR) spectra analysis and scanning electron microscopy (SEM), the characteristics of the montmorillonite-supported Fe-Ni nanocomposites were studied in detail. BET analysis shows that montmorillonite restrains the aggregation of Fe-Ni to reduce the size of its particles. By adding montmorillonite, Fe-Ni materials are transformed into uniform mesoporous structures, which are beneficial for adsorption and catalysis. The layers of montmorillonite and zero-valent metal constitute a "house-of-cards" structure. Based on FTIR spectral analysis, the stretching vibration of montmorillonite hydroxyl groups is present only in the spectra of supported nanoparticles and not in the spectra of unsupported nanoparticles. The degradation ability of different catalysts is tested by a series of experiments and measured by checking the remaining triclosan in polluted water. The test results confirmed that Mont/Fe-Ni nanoparticles exhibit the best removal efficiency, which is approximately 80% after 90 min.

The ability of dual whitening anti-caries mouthrinses to remove extrinsic staining and enhance caries lesion remineralization - An in vitro study

OBJECTIVES

This laboratory study investigated the ability of dual whitening anti-caries mouthrinses to remove extrinsic staining from artificially stained caries lesions and to enhance their remineralization and fluoridation.

MATERIALS AND METHODS

Early caries lesions were created in bovine enamel specimens. The lesions were artificially stained and pH cycled for 10 days with the daily cycling regimen consisting of twice daily 60s-treatments with one of 11 mouthrinses, a 4-h demineralization period and artificial saliva treatments in between. Mouthrinses were eight commercially available products, all containing 100ppm fluoride but utilizing hydrogen peroxide, pyro-, tri- or hexametaphosphate salts and/or sodium bicarbonate. The three control mouthrinses were 100ppm fluoride, 30 % hydrogen peroxide and deionized water. Enamel color changes (ΔE) were determined spectrophotometrically. Vickers surface microhardness (VHN) was used to determine lesion remineralization. Enamel fluoride content (EFC) was determined using the microbiopsy technique. Data were analyzed using ANOVA.

RESULTS

ΔE was significantly different among groups (p=0.0045). Thirty percent hydrogen peroxide was superior to all other mouthrinses, while there were no differences between commercial mouthrinses and deionized water. There were small, directional but non-significant differences between commercial mouthrinses with those containing hydrogen peroxide providing better whitening. There were no significant differences between mouthrinses in their ability to remineralize caries lesions (p=0.2898). EFC differed among groups (p<0.0001), with the two mouthrinses containing pyrophosphate salts having lower EFC than all but the deionized water group.

CONCLUSIONS

Artificially stained caries lesions show reduced susceptibility to fluoride remineralization and whitening effects of commercial whitening and anti-caries mouthrinses.

CLINICAL RELEVANCE

Artificially stained caries lesions appear to require stronger than over-the-counter interventions to successfully whiten and remineralizing them.

Two Randomized Trials Demonstrate Lactic Acid Supplementation in Pet Food Inhibits Dental Plaque, Calculus, and Tooth Stain in Cats

Background:

Dental concerns are some of the most common health problems affecting companion animals. A variety of foods, treats, and chews comprising different mechanical and chemical technologies have been investigated as a means of promoting oral health. Here, we investigate the chemical technology, lactic acid added to a commercially available food, for its ability to inhibit dental plaque, calculus, and tooth stain accumulation in cats.

Methods:

Two separate feeding trials assessed the utility of a nutritionally complete feline maintenance food supplemented with lactic acid to reduce oral substrate accumulation (dental plaque, calculus, and tooth stain) in cats. After a calibration study identified high and low dental plaque formers, 45 cats were randomized to 1 of 2 test groups (food with 1.2% lactic acid supplementation) or control (food without lactic acid supplementation) groups, stratified based on their calibration scores. Data were collected on a monthly basis for 3 months. The second study randomly assigned 24 cats to either the test or control groups for 1 year, with data collected at the 6- and 12-month time points.

Results:

In the 3-month study, reductions in dental plaque, calculus, and tooth stain accumulations were observed at the 2-month assessment in both test groups compared with control (P < .05 for test group 2). The 1-year study showed that these reductions in oral substrate accumulation persisted through the 6- and 12-month time points (P < .05).

Conclusions:

Taken together, these studies demonstrate that lactic acid supplemented at 1.2% in a feline maintenance food significantly inhibits oral substrate accumulation.

Triclosan antimicrobial polymers

Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling into a solid or alternatively applied as a coating through several different methods with dissolving into an organic solvent and dried on by evaporation as a common means.

Withania somnifera attenuates acid production, acid tolerance and extra-cellular polysaccharide formation of Streptococcus mutans biofilms

Withania somnifera (Ashwagandha) is a plant of the Solanaceae family. It has been widely used as a remedy for a variety of ailments in India and Nepal. The plant has also been used as a controlling agent for dental diseases. The aim of the present study was to evaluate the activity of the methanol extract of W. somnifera against the physiological ability of cariogenic biofilms and to identify the components of the extract. To determine the activity of the extract, assays for sucrose-dependent bacterial adherence, glycolytic acid production, acid tolerance, and extracellular polysaccharide formation were performed using Streptococcus mutans biofilms. The viability change of S. mutans biofilms cells was also determined. A phytochemical analysis of the extract was performed using TLC and LC/MS/MS. The extract showed inhibitory effects on sucrose-dependent bacterial adherence (≥ 100 μg/ml), glycolytic acid production (≥ 300 μg/ml), acid tolerance (≥ 300 μg/ml), and extracellular polysaccharide formation (≥ 300 μg/ml) of S. mutans biofilms. However, the extract did not alter the viability of S. mutans biofilms cells in all concentrations tested. Based on the phytochemical analysis, the activity of the extract may be related to the presence of alkaloids, anthrones, coumarines, anthraquinones, terpenoids, flavonoids, and steroid lactones (withanolide A, withaferin A, withanolide B, withanoside IV, and 12-deoxy withastramonolide). These data indicate that W. somnifera may be a potential agent for restraining the physiological ability of cariogenic biofilms.

Confusion over live/dead stainings for the detection of vital microorganisms in oral biofilms--which stain is suitable?

BACKGROUND

There is confusion over the definition of the term "viability state(s)" of microorganisms. "Viability staining" or "vital staining techniques" are used to distinguish live from dead bacteria. These stainings, first established on planctonic bacteria, may have serious shortcomings when applied to multispecies biofilms. Results of staining techniques should be compared with appropriate microbiological data.

DISCUSSION

Many terms describe "vitality states" of microorganisms, however, several of them are misleading. Authors define "viable" as "capable to grow". Accordingly, staining methods are substitutes, since no staining can prove viability.The reliability of a commercial "viability" staining assay (Molecular Probes) is discussed based on the corresponding product information sheet: (I) Staining principle; (II) Concentrations of bacteria; (III) Calculation of live/dead proportions in vitro. Results of the "viability" kit are dependent on the stains' concentration and on their relation to the number of bacteria in the test. Generally this staining system is not suitable for multispecies biofilms, thus incorrect statements have been published by users of this technique.To compare the results of the staining with bacterial parameters appropriate techniques should be selected. The assessment of Colony Forming Units is insufficient, rather the calculation of Plating Efficiency is necessary. Vital fluorescence staining with Fluorescein Diacetate and Ethidium Bromide seems to be the best proven and suitable method in biofilm research.Regarding the mutagenicity of staining components users should be aware that not only Ethidium Bromide might be harmful, but also a variety of other substances of which the toxicity and mutagenicity is not reported.

SUMMARY

- The nomenclature regarding "viability" and "vitality" should be used carefully.- The manual of the commercial "viability" kit itself points out that the kit is not suitable for natural multispecies biofilm research, as supported by an array of literature.- Results obtained with various stains are influenced by the relationship between bacterial counts and the amount of stain used in the test. Corresponding vitality data are prone to artificial shifting.- As microbiological parameter the Plating Efficiency should be used for comparison.- Ethidium Bromide is mutagenic. Researchers should be aware that alternative staining compounds may also be or even are mutagenic.

Osteopontin reduces biofilm formation in a multi-species model of dental biofilm

BACKGROUND

Combating dental biofilm formation is the most effective means for the prevention of caries, one of the most widespread human diseases. Among the chemical supplements to mechanical tooth cleaning procedures, non-bactericidal adjuncts that target the mechanisms of bacterial biofilm formation have gained increasing interest in recent years. Milk proteins, such as lactoferrin, have been shown to interfere with bacterial colonization of saliva-coated surfaces. We here study the effect of bovine milk osteopontin (OPN), a highly phosphorylated whey glycoprotein, on a multispecies in vitro model of dental biofilm. While considerable research effort focuses on the interaction of OPN with mammalian cells, there are no data investigating the influence of OPN on bacterial biofilms.

METHODOLOGY/PRINCIPAL FINDINGS

Biofilms consisting of Streptococcus oralis, Actinomyces naeslundii, Streptococcus mitis, Streptococcus downei and Streptococcus sanguinis were grown in a flow cell system that permitted in situ microscopic analysis. Crystal violet staining showed significantly less biofilm formation in the presence of OPN, as compared to biofilms grown without OPN or biofilms grown in the presence of caseinoglycomacropeptide, another phosphorylated milk protein. Confocal microscopy revealed that OPN bound to the surface of bacterial cells and reduced mechanical stability of the biofilms without affecting cell viability. The bacterial composition of the biofilms, determined by fluorescence in situ hybridization, changed considerably in the presence of OPN. In particular, colonization of S. mitis, the best biofilm former in the model, was reduced dramatically.

CONCLUSIONS/SIGNIFICANCE

OPN strongly reduces the amount of biofilm formed in a well-defined laboratory model of acidogenic dental biofilm. If a similar effect can be observed in vivo, OPN might serve as a valuable adjunct to mechanical tooth cleaning procedures.

Plaque-left-behind after brushing: intra-oral reservoir for antibacterial toothpaste ingredients

Objectives

Plaque is never fully removed by brushing and may act as a reservoir for antibacterial ingredients, contributing to their substantive action. This study investigates the contribution of plaque-left-behind and saliva towards substantivity of three antibacterial toothpastes versus a control paste without antibacterial claims.

Materials and methods

First, volunteers brushed 2 weeks with a control or antibacterial toothpaste. Next, plaque and saliva samples were collected 6 and 12 h after brushing and bacterial concentrations and viabilities were measured. The contributions of plaque and saliva towards substantivity were determined by combining control plaques with experimental plaque or saliva samples and subsequently assessing their viabilities. Bacterial compositions in the various plaque and saliva samples were compared using denaturing gradient gel electrophoresis.

Results

The viabilities of plaques after brushing with Colgate-Total® and Crest-Pro-Health® were smaller than of control plaques and up to 12 h after brushing with Crest-Pro-Health® plaques still contained effective, residual antibacterial activity against control plaques. No effective, residual antibacterial activity could be measured in saliva samples after brushing. There was no significant difference in bacterial composition of plaque or saliva after brushing with the different toothpastes.

Conclusions

Plaque-left-behind after mechanical cleaning contributes to the substantive action of an antibacterial toothpaste containing stannous fluoride (Crest-Pro-Health®).

Clinical relevance

The absorptive capacity of plaque-left-behind after brushing is of utmost clinical importance, since plaque is predominantly left behind in places where its removal and effective killing matter most. Therewith this study demonstrates a clear and new beneficial effect of the use of antibacterial toothpastes.

Antibacterial activity of reactive quaternary ammonium compounds in solution and in nonleachable coatings

Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), endowed with undecylacryloyl group and alkyl chains with 2 (QAM-C2), 8 (QAM-C8), and 16 (QAM-C16) carbon atoms have been synthesized. Aqueous solutions of QAMs showed biocidal activity against Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains both in suspension and adhered to stainless steel surfaces. QAM-C16 and QAM-C8 evidenced higher activity toward bacteria in suspension and on stainless steel, respectively. The QAMs have shown sufficient reactivity to be copolymerized, by UV irradiation, with a commercial urethane acrylic resin for coating. Bioactivity tests, performed on free films of crosslinked coatings containing 1% of copolymerized QAM, have shown an increasing inactivation effect in the order of magnitude L. monocytogenes, E. coli, S. aureus with a maximum activity of the QAM-C8.

Separation of an effective fraction from turmeric against Streptococcus mutans biofilms by the comparison of curcuminoid content and anti-acidogenic activity

Turmeric has long been used as a colouring and flavouring agent for foods. Curcuminoids are the main component of turmeric and have a range of pharmacological activities. In this study, a fraction that could show anti-biofilm activity was separated from turmeric, based on a comparison of curcuminoid content and anti-acidogenic activity against Streptococcus mutans, and the effects of the separated fraction and curcuminoids on the adherence ability of S. mutans and the physiological ability of S. mutans biofilms were examined at sub-minimum inhibitory concentration (MIC) levels. The separated fraction and curcuminoids had inhibitory effects on the sucrose-dependant adherence of S. mutans to saliva-coated hydroxyapatite (sHA) discs and the acidogenicity and aciduricity of S. mutans biofilms. These results suggest that the separated turmeric fraction and its components, curcuminoids, may be useful for controlling dental biofilms and subsequent dental caries formation.

Treatment protocols: nonfluoride management of the caries disease process and available diagnostics

This article reviews the evidence for saliva diagnostics and some antibacterial concepts with potential to interfere with the caries process. It concludes that there is incomplete evidence to evaluate the role of chair-side tests and to recommend general topical applications of antibacterial agents to prevent caries lesions. However, such measures may be considered to control the disease in caries-active individuals. There is evidence that xylitol has antibacterial properties that alter the oral ecology but the clinical evidence for caries prevention is rated as fair. However, preventive programs should include as many complementary strategies as possible, especially when directed toward caries-active patients. Therefore, any antibacterial intervention should always be combined with a fluoride program, until stronger evidence for its use in caries prevention and management becomes available.

In vitro stability of triclosan in dentifrice under simulated use condition

Triclosan has been formulated into a dentifrice at a 0.3% level to enhance the antibacterial function of the dentifrice, to improve oral health and to decrease the daily malodor inside the mouth cavity. The hypothesis that chloroform may be generated from triclosan when contacted with chlorinated drinking water has challenged our guarantee of safe use of triclosan in oral care products, especially in Colgate Total toothpaste. Currently, there was no available analytical method to detect chloroform levels under the use conditions expected during daily tooth brushing. To fill this gap and to continue guaranteeing that our customers can safely use Colgate Total toothpaste products, a gas chromatography-single ion monitoring-mass spectrometry method for detecting chloroform in artificial saliva media has been developed. The limit of detection (LOD) and limit of quantitation are about 41 and 130 ppb, respectively. This LOD level is lower than the current Environmental Protection Agency trihalomethanes contamination limit, which is required for our daily drink water. Our in vitro study indicated that Colgate Total does not form detectable chloroform levels (41 ppb) over the range of expected consumer-brushing times while using normal chlorinated drinking water.

Novel technologies for the prevention and treatment of dental caries: a patent survey

IMPORTANCE OF THE FIELD

Dental caries is one of the most common preventable childhood diseases; people are susceptible to this ailment throughout their lifetime. In the US, 90% of late adolescents and young adults have dental caries, while 94% of all dentate adults had evidence of treated or untreated coronal caries. Dental caries is often not self-limiting and without proper care can progress until the tooth is destroyed.

AREAS COVERED IN THIS REVIEW

In this paper, the etiology of dental caries is briefly introduced. It is followed by a thorough review of patents and literatures on the recent development of various novel technologies for the prevention and treatment of dental caries.

WHAT THE READER WILL GAIN

Recent advances in anti-plaque agents, including chemoprophylactic agents, antimicrobial peptides, vaccines, probiotics/replacement therapy and sugar substitutes, and remineralization agents including fluorides and casein phosphopeptides are analyzed. TAKE HOME MASSAGE: Both the discovery of new anti-caries agents and the development of dentotropic delivery systems will be the future focus of this research field.

In vitro anti-bacterial and anti-adherence effects of natural polyphenolic compounds on oral bacteria

AIMS

To investigate the action of different polyphenolic compounds, extracted from red wine, grape marc and pine bark, on oral bacteria.

METHODS AND RESULTS

The anti-microbial activity of extracts was examined by determining the Minimal Inhibitory Concentration and Minimal Bactericidal Concentration using the macro dilution broth technique. Their effect on the adherence was tested on growing cells of Streptococcus mutans on a glass surface and on a multi-species biofilm grown on saliva-coated hydroxyapatite discs. The effect on glucosyltransferase activity was analysed through the reductions in the overall reaction rate and the quantity of insoluble glucan (ISG) synthesized. Pine bark and grape marc extracts were the most effective inhibitors of the multi-species biofilm formation and of the ISG synthesis.

CONCLUSION

The tested components showed an interesting anti-plaque activity in vitro.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is, to our knowledge, the first and the most complete report on the properties of wine and pine bark extracts that could be used for oral disease prevention purpose.

Effect of N-chlorotaurine mouth rinses on plaque regrowth and plaque vitality

The purpose of this 4-day plaque regrowth study was to assess the effect of N-chlorotaurine (NCT) mouth rinses on plaque inhibition and plaque vitality. Eighty volunteers participated in this investigator-blind, randomized, clinical controlled study in parallel groups. No oral hygiene was permitted except rinsing with a 2% or 3% NCT mouth rinse, a positive or a negative control. Primary parameters were the plaque index (Silness and Löe, Acta Odontol Scand, 22:121-135, 1964) and plaque vitality (Netuschil et al., J Clin Periodontol, 16:484-488, 1989) after the final rinse. In addition, another plaque index (Turesky et al., J Periodontol, 41:41-43, 1970), plaque area, and bleeding on probing were recorded. All parameters were taken at baseline and day 5. U test was applied on a 5% error level. No differences in plaque inhibition were found between the two NCT formulations and the negative control. However, a statistically significant reduction of plaque vitality compared to the negative and positive control was observed. Discoloration of the tongue and unpleasant taste were recorded in participants in the NCT groups. NCT mouth rinses did not inhibit plaque regrowth, but they did reduce the vitality of plaque bacteria. Methods of prolonging the substantivity of the NCT mouth rinses should be investigated to enhance the antibacterial properties of these formulations.

In vitro inhibitory effects of Polygonum cuspidatum on bacterial viability and virulence factors of Streptococcus mutans and Streptococcus sobrinus

OBJECTIVES

Polygonum cuspidatum has been used in Korean folk medicine to improve oral hygiene. This study was performed to evaluate the effects of methanol extract from root of P. cuspidatum (MEP) on bacterial viability and the virulence factors of Streptococcus mutans and Streptococcus sobrinus.

METHODS

To test the effects of MEP on bacterial viability, we determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against 20 bacterial strains, including S. mutans and S. sobrinus, using a micro-dilution assay. In case of S. mutans and S. sobrinus, the assays for time-kill and bacterial growth rate at sub-MIC concentrations were also performed. To determine effects of the extract on the virulence factors of S. mutans and S. sobrinus, the assays for sucrose-dependent adherence, water-insoluble glucan formation, glycolytic acid production, and acid tolerance were performed at sub-MIC levels. Phytochemical analysis for constituents of MEP was carried out.

RESULTS

MEP showed a broad antibacterial range (MIC 0.5-4 mg/ml). The MBC was two to four times higher than the MIC. The time-kill curves showed S. mutans and S. sobrinus were significantly killed after 1h of incubation. At sub-MIC levels, doubling times of S. mutans and S. sobrinus dose-dependently increased up to 211% and 123%, respectively. At sub-MIC levels, MEP also showed inhibitory effects on the virulence factors of S. mutans and S. sobrinus in a dose-dependent fashion. Phytochemical analysis revealed the presence of alkaloids, sterol/terpenes, tannins, flavonoids, and carbohydrates.

CONCLUSION

These data indicate that MEP has inhibitory effects on bacterial viability at higher concentrations (> or =MIC) and the virulence factors of S. mutans and S. sobrinus at sub-MIC concentrations, suggesting that it might be useful for the control of dental plaque formation and subsequent dental caries formation.

In vitro anti-cariogenic activity of dichloromethane fraction from Rheum undulatum L. root

This study aimed to evaluate in vitro effects of Rheum undulatum L. root on the development of dental caries, especially its effects on viability, dental plaque formation, and glycolytic acid production of Streptococcus mutans and Streptococcus sobrinus. Methanol extract of Rheum undulatum L. root and its fractions were prepared and tested. Among the test extract and fractions, dichloromethane fraction (DF) showed the most active antibacterial activity (inhibition zone: 13-17 mm) against S. mutans and S. sobrinus in a disc diffusion method. Minimal inhibitory concentrations (MICs) of DF against these bacteria ranged from 0.25 to 0.5 mg/mL. Furthermore, DF significantly inhibited the caries-inducing factors of these bacteria. At sub-MIC levels, DF inhibited in vitro dental plaque formation by S. mutans and S. sobrinus (IC50= 0.079 and 0.142 mg/mL, respectively), which was caused, in part, by the inhibitory effect on the activity of glucosyltransferases. A significant reduction of glycolytic acid production was found at the concentration as low as 0.032 mg/mL for S. mutans and 0.063 mg/mL for S. sobrinus. The possible bioactive compounds that are inducing in vitro anti-cariogenic activity of DF are unknown. Based on the preliminary phytochemical analysis, the activity of DF may be related to the presence of anthraquinones, cardiac glycosides, coumarines, sterols/terpenes, and phenolics. These results indicate that DF is probably useful for the control of dental plaque formation and subsequent dental caries development.

Differences in efficacy of two commercial 0.2% chlorhexidine mouthrinse solutions: a 4-day plaque re-growth study

BACKGROUND

The purpose of this clinical cross-over study was to examine the antibacterial and plaque-inhibiting properties of two chlorhexidine solutions compared with a negative control.

MATERIAL AND METHODS

Twenty-one volunteers refrained from all oral hygiene measures, but rinsed instead twice daily with 10 ml of a conventional chlorhexidine solution (0.2%; CHX), a chlorhexidine solution with anti-discolouration system (ADS) (0.2%, alcohol-free chlorhexidine solution (CSP)) or a placebo solution (Pla). Plaque index (PI), plaque area (PA) and bacterial vitality were assessed after 24 h (PI1, vital flora (VF)1) and 96 h (PI2; VF2, PA). After a 10-day wash-out period, a new test cycle was started.

RESULTS

Results for Pla were 0.94, 1.59, 27.4 (PI1, PI2, PA) and 79% and 72% (VF1 and VF2). CSP significantly reduced the parameter PI1, PI2 and PA to 0.67 (p=0.012), 1.0 and 15.7 (p<0.001). VF1 and VF2 (63% and 53%) were not significantly affected. The corresponding figures of CHX were 0.42, 0.43, 6.77, 33 and 16%, which were all significantly lower (all p<0.001). On comparing the two chlorhexidine solutions, CHX showed significantly higher reductions of all parameters.

CONCLUSION

The results suggest that the 0.2% alcohol-containing solution showed superiority in inhibiting plaque re-growth and reducing bacterial vitality compared with the solution with ADS.

Sustained-release delivery systems of triclosan for treatment ofStreptococcus mutans biofilm

Dental diseases are chronic infections caused by oral bacteria harboring the dental biofilm. Local sustained-release delivery systems prolong the duration of a drug in the oral cavity, thus enhancing its therapeutic potential, while reducing its side effects. Triclosan is an agent that was found to have an antibacterial effect against oral bacteria. However, its substantivity in the oral cavity is low, resulting in reduced antibacterial efficiency. The purpose of this study was to develop a local sustained release device containing triclosan and to test its antibacterial efficacy on Streptococcus mutans biofilm. Our results show that we can formulate an ethylcellulose-based, nondegradable, sustained-release device in which 80% of the loaded triclosan is released over a 10-day period. The release rate of triclosan corresponded to the Higuchi's planar homogenous diffusion release model (r2 = 0.998). A degradable local sustained-release delivery based on a methacrylate ester matrix was also developed for a faster release rate of triclosan. The release kinetics in those types of sustained-release delivery systems was erosion control. The local sustained-release delivery system significantly affected the viability of S. mutans in biofilm compared to placebo as was tested by confocal laser scanning microscopy. Our in vitro results show that triclosan can be incorporated into degradable or nondegradable sustained-release drug delivery systems. The release of triclosan from the local sustained-release delivery system can be controlled, thus extending its antibacterial properties.

The effect of a new toothpaste containing potassium nitrate and triclosan on gingival health, plaque formation and dentine hypersensitivity

OBJECTIVES

The purpose of this study was to investigate the effect of a new toothpaste containing an antiplaque and antiinflammatory agent (0.3% triclosan), a desensitizing agent (5% potassium nitrate) and an anticaries agent (0.76% sodium monofluorophosphate (SMFP)) on gingival health, plaque formation and dentine hypersensitivity in a 12-week home study. The efficacy of the test toothpaste was compared with that of a control toothpaste containing 5% potassium nitrate and 0.76% SMFP and a benchmark product containing only 0.76% SMFP.

MATERIAL AND METHODS

One hundred and two healthy volunteers, who had a minimum of 20 natural permanent teeth with no probing depth >4 mm and at least one sensitive tooth, participated in this study. Following enrollment, the subjects received a dental prophylaxis and instruction in brushing technique. After a 4-week pre-experimental phase, baseline gingival bleeding index (GBI), plaque index (PI) and visual analogue scales (VASs) indicating dentine hypersensitivity levels responding to tactile and air stimuli were assessed. The subjects were then randomly given one of the three toothpastes; test, control, or benchmark toothpaste, and a soft-filamented toothbrush for home use. The GBI, PI and VASs were re-examined at weeks 4 and 12.

RESULTS

Overall, the GBI scores were significantly reduced compared with baseline in all groups (p<0.01). However, there was no significant difference in GBI score among the three comparison groups. The PI score decreased in the test group and benchmark group from baseline to the end of study, whereas there was no significant change in the control group. Post hoc comparison indicated that the PI score was not statistically different between the three groups. There was a significant difference between the three treatment groups for sensitivity. For both the tactile and air stimuli, the reductions in VAS sensitivity scores for the test group and the control group were significantly greater compared with the benchmark group. Although the sensitivity score for air stimulus decreased more rapidly from baseline to week 4 in the test group, there was no overall difference between the test group and the control group.

CONCLUSIONS

This study demonstrated that the new toothpaste was effective in reducing dentine hypersensitivity. More studies are needed to further determine the potential interaction between triclosan and potassium nitrate in dentifrices.

The role of Triclosan in dentifrice formulations, with particular reference to a new 0.3% Triclosan calcium carbonate-based system

AIM

To discuss the role of Triclosan in dentifrice systems and demonstrate the enhanced efficacy of Triclosan in calcium carbonate-based systems when the level of the antimicrobial agent is raised from 0.2% to 0.3%. Triclosan is the most commonly used antimicrobial agent in oral care products, being compatible with a wide range of ingredients found in toothpaste formulations, whilst having no negative sensory features (e.g. taste, staining) that are associated with some other antimicrobial/anti-plaque agents. Triclosan is a broad spectrum antimicrobial agent, with additional anti-metabolic and anti-inflammatory properties. When delivered to the mouth in oral care products, Triclosan can selectively inhibit Gram negative anaerobic bacteria implicated in gingivitis and periodontal diseases, while leaving species associated with oral health relatively unaffected. Worldwide, attempts have been made to boost delivery/activity of Triclosan, either by use of copolymers or by combination with other agents such as zinc citrate. However, Triclosan has also been shown to maintain clinical efficacy against plaque and gingivitis when present as the sole antimicrobial in toothpaste formulations.

The oral environment: the challenge for antimicrobials in oral care products

For any antibacterial/ anti-plaque system from an oral care product to be effective, it must firstly be delivered and retained at relevant sites in the oral cavity and secondly, remain active within the chosen formulation to successfully target the biofilm cells within dental plaque. This must include inhibition of the growth and metabolism of relevant organisms associated with disease. This review will concentrate on understanding the environmental conditions in which such oral care products must work and summarise the activity within the oral cavity of the main antibacterial and anti-plaque agents in common oral care products, namely chlorhexidine, essential oils, metal salts and Triclosan. Routes to further enhance the activity of these products, together with the use of relatively novel formats such as confectionery products to provide added consumer oral health benefits will be considered.

The effect of a toothpaste containing 2% zinc citrate and 0.3% Triclosan on bacterial viability and plaque growth in vivo compared to a toothpaste containing 0.3% Triclosan and 2% copolymer

OBJECTIVE

To compare the antimicrobial efficacy and effect on plaque growth of a new silica-based fluoride toothpaste containing 2% zinc citrate/ 0.3% Triclosan with a silica-based fluoride toothpaste containing 0.3% Triclosan/2% copolymer.

METHODS

In Study 1, plaque was collected after one week's use of each toothpaste and assessed for bacterial viability, live/ dead ratio and microbial membrane integrity. In study 2, plaque was measured immediately and 18 hours after a single brushing with the specified toothpastes.

RESULTS

The 2% zinc citrate/0.3% Triclosan formulation significantly reduced the total number of viable aerobic and anaerobic bacteria (p = 0.0223 and p = 0.0443 respectively) compared to the 0.3% Triclosan/2% copolymer formulation. Both toothpastes increased the bacterial membrane permeability significantly. However, the proportion of live bacteria for the 2% zinc citrate/0.3% Triclosan product was significantly reduced (p < 0.05). Study 2 showed significantly less plaque growth 18 hours after using the 2% zinc citrate/0.3% Triclosan toothpaste compared to the 0.3% Triclosan/2% copolymer toothpaste (p < 0.01).

CONCLUSION

Regular use of a fluoride toothpaste containing 2% zinc citrate and 0.3% Triclosan, significantly reduced the viability of plaque bacteria compared to a fluoride toothpaste containing 0.3% Triclosan/ 2% copolymer 12 hours after brushing. In addition, a clinical plaque growth study confirmed that this anti-microbial efficacy leads to a significant reduction in plaque growth.

Effect of a triclosan-containing dental gel on the levels of prostaglandin I2 and interleukin-1beta in gingival crevicular fluid from adolescents with fixed orthodontic appliances

The effect of a triclosan-containing (0.3%) dental gel on inflammatory mediators in gingival crevicular fluid (GCF) was evaluated in 14 healthy adolescents undergoing orthodontic treatment with fixed appliances. A double-blind randomized split-mouth study design was used with color-coded experimental and placebo gels. The gel was self-applied for 5 min twice daily for 14 days in custom-made soft plastic trays. Clinic al data (visible plaque index (VPI) and gingival bleeding index (GBI) and samples of GCF were collected at baseline and after 1, 2, 4, and 6 weeks. The concentrations of prostaglandin I2 (PGI2) and interleukin-1beta (IL-1beta were determined by radioimmuno- and enzyme-linked immunosorbent assays, respectively. No clinical effects of the gel applications regarding amount of plaque or gingival bleeding were unveiled. Neither the experimental nor the placebo gel applications caused any statistically significant alterations in the inflammatory mediators, PGI2 and IL-1beta, compared to baseline. In conclusion, the present study did not reveal any beneficial cffects of the triclosan-containing gel regimen on mild gingivitis in adolescents with fixed orthodontic appliances.

Efficacy of an amine fluoride-triclosan mouthrinse as compared to the individual active ingredients

BACKGROUND

The purpose of the clinical study was to examine the antibacterial and plaque-reducing properties of mouthrinses containing triclosan (TRI), amine fluoride (AmF), and the combination of both (AFT) on 4-day plaque regrowth. A placebo solution (PLA) and a 0.2% chlorhexidine solution (CHX) served as negative and positive controls, respectively.

MATERIALS AND METHODS

After a professional tooth cleaning (day 0), 15 volunteers refrained from all mechanical oral hygiene measures for the next 96 h and rinsed instead twice daily for 1 min with 10 ml of one of the five randomly assigned solutions. Plaque index (PlI), which was assessed after 24 and 96 h (PlI1, PlI2), and plaque area of the front teeth (PA), which was planimetrically recorded from disclosed teeth after 96 h, served as clinical parameters. After 24 and 96 h a plaque sample was taken and analyzed microbiologically to evaluate biofilm vitality (VF1, VF2). The subsequent test cycles were conducted after a washout period of 10 days each.

RESULTS

No severe adverse events or allergy were seen during the study. CHX influenced all parameters at all time points in comparison to PLA. AFT and AmF showed very similar values (in all parameters), but AmF did not reach the level of significance regarding VF1, nor did AFT with VF2 and PlI1. The TRI solution only reduced PlI2 and PA significantly, but had no influence on biofilm vitality when compared to PLA.

CONCLUSION

A synergism between AmF and TRI was not observed. The results suggest that the plaque-reducing and antibacterial effects of the AFT solution are mainly based on the effects of the amine fluoride moiety.

Antiplaque biocides and bacterial resistance: a review

Modern dentistry emphasizes the importance of dental plaque control to improve oral health. The use of oral care formulations with antiplaque biocides plays a crucial role in patient-directed approaches for plaque control. The antiplaque efficacies of these formulations have been extensively studied in many long-term clinical studies designed in accordance with well-accepted guidelines. The results from these studies conclusively demonstrate that long-term use of oral care formulations with well-known antiplaque biocides such as chlorhexidine and triclosan reduce supragingival plaque and gingivitis. This review summarizes microbiological results from clinical studies conducted with oral care formulations containing antiplaque biocides. Results from a number of long-term clinical studies conducted under real-life use conditions indicate no adverse alterations in the bacteria found in dental plaque or emergent microbial resistance. Additionally, microbial sampling of dental plaque subsequent to extended use of antiplaque biocides reveals no increase in resistant microflora. Large numbers of common oral bacteria isolated from patients using chlorhexidine indicate no increase in microbial resistance to chlorhexidine or to commonly used antibiotics. The effects of antiplaque biocides containing oral care formulations on dental plaque that exists naturally as a biofilm are examined. These formulations contain biocide, surfactants, polymers and other components that are effective against the biofilm. In summary, the results of studies on the real-life use of oral care formulations with antiplaque biocides show no emergence of resistant microflora or alterations of the oral microbiota, while such formulations have been found to provide the benefits of reducing plaque and gingivitis.

Substantivity of toothpaste slurries and their effect on reestablishment of the dental biofilm

OBJECTIVES

Toothpastes are good vehicles for antibacterial substances to exert a prolonged effect. This effect depends on the substantivity and ability to interfere with plaque metabolism and/or vitality. It was the purpose of this clinical, randomized 2 x 4 cell crossover study to evaluate and to compare the antibacterial effects of two toothpastes (Colgate Total(R), COL and Parodontax(R), PAR) applied as slurries on established plaque over 24 h (Part I) and their effect on 4-day plaque regrowth (Part II). Chlorhexamed(R) (0.1%; CHX) and water served as positive and negative controls.

MATERIAL AND METHODS

After professional toothcleaning eight students were asked to refrain from all mechanical hygiene measures for the next 72 h. After 48 h plaque was sampled and vitality of the plaque flora examined (baseline, VF0%). The subjects then rinsed for 1 min with 15 mL of one of the test or control solutions. Every second hour up to 14 h and 24 h after rinsing, plaque sampling and staining was performed to assess plaque vitality (VF2-24, Part I). In Part II, the classical 4-day plaque regrowth design was used with two rinses (1 min) a day as the only oral hygiene measure. Vitality values were assessed on day 1 and day 4 (VF1, VF2). At day 4, teeth were stained to assess the whole mouth plaque index (PlI) and to evaluate the percentage of plaque area (PA) of the anterior teeth.

RESULTS

Compared to placebo, all active rinses reduced plaque vitality significantly over a period of 24 h (Part I). PAR, COL and CHX revealed reductions of 18-31%, 28-50% and 19-50%, respectively. In Part II, similar reductions of all parameters were found for all active rinses (PAR 12-30%, COL 34-51%, CHX 40-64%).

CONCLUSIONS

Colgate Total has shown a significant action on plaque regrowth and a high substantivity during 24 h, while Parodontax revealed a more moderate but still significant effect.

Determination of triclosan in personal health care products by liquid chromatography (HPLC)

An isocratic reversed-phase liquid chromatographic (HPLC) method is proposed for the practical and reliable determination of triclosan, an antimicrobic agent incorporated into a variety of personal heath care products. Chromatographic separations were performed on a C-18 column using acetonitrile-TEA phosphate (70 mM; pH 3.5) 55:45 (v/v) as mobile phase and UV detection at 230 and 280 nm. The selectivity of the method was assured by the on-line photodiode array detector. The identity of the triclosan peak was also confirmed by HPLC MS. The method was successfully applied to the determination of triclosan in commercially available health care products (deodorant stick, dentifrice gel, mouthrinse, toothpaste and handwash). All the products displayed triclosan concentrations in compliance with the EEC directive (< or = 0.3%,).

Effect of an amine-fluoride-triclosan mouthrinse on plaque regrowth and biofilm vitality

BACKGROUND

The purpose of this double-blind, prospective, latin-square crossover randomised study was to examine the efficacy of a mouthrinse solution containing a combination of triclosan, amine fluoride and sodium fluoride on supragingival plaque regrowth compared to a placebo and a chlorhexidine solution.

METHODS

12 volunteers refrained after professional oral prophylaxis from all mechanical hygiene measures for the following 96 h and rinsed instead cross-over in a randomised order with either chlorhexidine digluconate (0.2%, positive control), a verum solution (0.5% amine fluoride, 0.028% sodium fluoride, 0.03% triclosan) or a placebo solution. The plaque index was assessed after 24 and 96 h (PI 1, PI 2) and the plaque area (PA) photographed and calculated after 96 h of undisturbed plaque regrowth. Moreover plaque samples were taken after 24 and 96 h and examined with the vital fluorescence technique to assess the vitality of the biofilm microbiota (VF 1, VF 2).

RESULTS

The amine-fluoride-triclosan solution reduced the clinical parameters (PI and PA) as well as the vitality of the plaque flora (VF) significantly when compared to the placebo solution. The verum reached a 36.5% (p<0.05) and a 39.8% reduction (p<0.0001) in PI 1 and PI 2, respectively, concomittant with a reduction of 23.8% and 32.2% (p<0.001) in VF 1 and VF 2 and of 46.9% (p<0.0001) in PA at day 4. This was less than the reductions found with the positive control, i.e., the 0.2% chlorhexidine solution (54.2% and 71.1% reduction in PI 1 and PI 2, 40.0% and 53.4% in VF 1 and VF 2 and 71.5% in PA). However, significant differences between both active solutions were only established for PI 2 and PA.

CONCLUSION

During 4-day plaque regrowth the amine-fluoride-triclosan product displayed a significant antibacterial and plaque-reducing action in comparison to the control.

Clinical effect of a new liquid dentifrice containing triclosan/copolymer on existing plaque and gingivitis

BACKGROUND

Dentifrices traditionally have been formulated as pastes or gels. However, liquid varieties recently have become available The authors conducted a study to determine whether a fluoridated liquid product with added triclosan and a polyvinyl methyl ether/maleic acid, or PVM/MA, copolymer delivery system is efficacious for the control of supragingival plaque and gingivitis.

METHODS

The authors conducted a six-month, double-blind, parallel, stratified clinical study in accordance with American Dental Association guidelines for the clinical evaluation of antiplaque/antigingivitis products. Subjects who qualified with a suitable amount of existing plaque and gingivitis were given one of two dentifrices: an "experimental" liquid dentifrice containing 0.3 percent triclosan, 2.0 percent PVM/MA copolymer and 0.243 percent sodium fluoride, or NaF, in a silica base; or a "placebo" dentifrice containing 0.243 percent NaF in a silica base. The authors collected subjects' plaque and gingival index scores at baseline, three months and six months.

RESULTS

The results of the study indicate that the use of the experimental liquid dentifrice provided a significant reduction in existing levels of plaque and gingivitis as compared with the placebo standard dentifrice. At six months, the experimental group demonstrated a 34.9 percent reduction in plaque formation and a 25.7 percent reduction in gingivitis as compared with the placebo group (P < .001).

CONCLUSIONS

When compared with the placebo, the experimental dentifrice had a significantly better ability to reduce plaque and gingivitis. When compared with results reported in the literature, this new form of dentifrice achieved results comparable in efficacy to those of traditional dentifrice pastes with matching active ingredients.

CLINICAL IMPLICATIONS

This study confirms that a liquid dentifrice containing a triclosan/copolymer/NaF delivery system is efficacious in its ability to reduce existing plaque and gingivitis.

Effects of triclosan on the cytotoxicity and fungal growth on a soft denture liner

STATEMENT OF PROBLEM

Contamination of removable prostheses with microorganisms, particularly Candida albicans, is a common clinical problem. Microban, a broad-spectrum antimicrobial containing triclosan, recently has been proposed to inhibit microbial growth.

PURPOSE

This study aimed to determine whether the addition of Microban to PermaSoft denture liner prevents the growth of C albicans and affects the cytotoxicity of the PermaSoft material.

MATERIAL AND METHODS

Experimental specimen disks (5 x 1 mm each) with and without incorporated Microban were fabricated aseptically (n = 6) against polyester film to produce a smooth surface. To assess the cytotoxic effect of Microban, the MTT assay was used. To determine the effect of Microban on the growth of C albicans, disks were placed in Transwell dishes, covered with Sabouraud's broth containing an ATCC strain of C albicans, and incubated at 37 degrees C for 24 hours. Wells containing fluorocarbon resin disks or broth alone served as controls. The disks were rinsed to remove unattached C albicans and then sonicated in sterile water to remove surface organisms. Serial dilutions of the water extracts were plated on Sabouraud's agar and returned to the incubator for 24 hours. Colonies were counted with a Brunswick Colony Counter. Growth of C albicans in the internal aspects of the specimens was determined in a manner as previously described, with the exception that the specimens were sonicated to remove surface organisms, minced, and sonicated once more before making serial dilutions. The results were compared with ANOVA and Tukey intervals (alpha=.05).

RESULTS

The number of colonies formed ranged from 17 to 31 x 10(5) (mean = 23 +/- 4 x 10(5)) and 14 to 69 x 10(5) (mean = 32 +/- 20 x 10(5)) for the PermaSoft with and without Microban groups, respectively. There was no statistically significant difference between PermaSoft with and without Microban.

CONCLUSION

The addition of Microban did not significantly alter the cytotoxicity of the PermaSoft denture lining material or reduce the adherence of viable C albicans to the surface of PermaSoft material after 24 hours.