In-vitro evidence for efficacy of antimicrobial mouthrinses

Cymbopogon citratus Essential Oil Increases the Effect of Digluconate Chlorhexidine on Microcosm Biofilms

The aim of this study was to evaluate the effect of the Cymbopogon citratus essential oil and its association with chlorhexidine on cariogenic microcosm biofilm composition and acidogenicity. Minimum inhibitory and bactericide concentrations from the essential oil and chlorhexidine were determined by broth microdilution assay. Microcosms (polymicrobial) biofilms were produced on glass coverslips, using inoculum from human saliva in McBain culture medium (0.5% sucrose exposure for 6 h/day) for 3 days in 24-well plates. The biofilms were treated twice a day and their composition was evaluated by microorganism quantification. The acidogenicity was evaluated by measuring the pH of the spent culture medium in contact with the biofilm. Overall, the association of C. citratus and chlorhexidine reduced total bacterial counts and aciduric bacteria (maximum reduction of 3.55 log UFC/mL) in microcosm biofilms. This group also presented the lowest acidogenicity even when exposed to sucrose-containing medium. C. citratus essential oil increases the effect of digluconate chlorhexidine on microcosm biofilms. Based on these findings, this study can contribute to the development of new formulations that might allow for the use of mouthwashes for a shorter period, which may reduce undesirable effects and increase patient compliance to the treatment.

Antimicrobial efficacy of Colgate Plax Cool Mint® mouthwash – in vivo studies

Hygienic procedures in oral cavity, both teeth brushing and using mouthwashes, have an influence on the composition and quantity of oral microflora. The aim of the work was to evaluate the impact of regular use of selected mouthwash on the titer of Lactobacillus and Streptococcus bacteria and Candida yeast-like fungi in the saliva.

The evaluation of the influence of Colgate Plax Cool Mint® mouthwash on the number of Lactobacillus and Streptococcus bacteria and Candida yeast-like fungi in the saliva was done. The research included 39 persons at the age of 17±3 months, out of whom 30 people constituted a study group using mouthwash and 9 people – a control group not using mouthwash. The persons from the study group used the mouthwash twice a day for 2–3 minutes for the period of 5 months. The material for the microbiological tests constituted 2 ml of saliva collected three times from the participants: at the beginning of the research – before the use of a mouthwash and respectively, after 2.5 and 5 months from the first test.

Colgate Plax Cool Mint®, the most frequently used by the youth in their daily oral hygiene and used in the present study mouthwash, showed effectiveness in reduction of Lactobacillus spp. and S. mutans bacteria, as well as C. albicans yeasts in the saliva of the studied persons, what is undoubtedly connected with inhibition of formation and prevention of oral plaque development.

Antimicrobial activity of mouth rinses against bacteria that initially colonizes dental’s surface

Abstract Introduction Much advertising in mouthwash is conveyed in all media appealing to the anti-plaque effect and rendering a disservice to the community. Mouth rinses are available over-the-count and differ on their compositions and antimicrobial effectiveness. Objective In this study, we evaluated the antimicrobial activity of 35 widely available mouth rinses against bacterial species involved in initiation of dental biofilm – Streptococcus gordonii, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius, and Streptococcus sanguinis. Material and method The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of the evaluated mouth rinses were determined according to the Clinical & Laboratory Standards Institute protocols. Data were submitted to Kruskal-Wallis test and Mann-Whitney post hoc (α=0.05). Result About 70% of the mouth rinses achieved high antibacterial activity and 30%, a low antibacterial activity against all the species tested. The most ineffective mouth rinse showed antibacterial activity (MIC) at 1:1 dilution, while the most effective showed activity even at 1:2048 dilution, which may imply prolonged effect in the mouth. About 51% of mouth rinses showed bactericidal activity, and it was verified that cetylpyridinium chloride or chlorhexidine digluconate containing in the formulation were associated with the highest activity. Conclusion Most - but not all - mouth rinses commercially available are effective in inhibiting in vitro initial colonizers of dental surfaces.

Antimicrobial action of chlorhexidine digluconate in self-ligating and conventional metal brackets infected with Streptococcus mutans biofilm

Objectives

The objectives of this study were to assess the adherence of Streptococcus mutans biofilms grown over conventional ligature (CL) or self-ligating (SL) metal brackets and their bacterial viability after 0.12% chlorhexidine (CHX) digluconate treatment.

Materials and methods

The sample consisted of 48 metallic orthodontic brackets divided randomly into two groups: CL (n=24) and SL brackets (n=24). S. mutans biofilms were grown over the bracket surface (96 h) and treated with CHX (positive control) or 0.9% phosphate-buffered saline (PBS) (negative control) for 1 min each. Quantitative analysis was assessed by colony-forming units, and fluorescence microscopy was performed aiming to illustrate the outcomes. The tests were done in triplicate at three different times (n=9). Data were analyzed using ANOVA and Tukey test (P<0.05).

Results

There were significant differences in brackets’ biofilm formation, being CL largely colonized compared with SL, which was observed by colony-forming unit counting (P<0.05) and microcopy images. Significant reduction in the viability of S. mutans was found in both brackets treated with CHX compared to PBS (P<0.05).

Conclusion

The antimicrobial activities of CHX were similar for CL and SL brackets (P>0.05). In conclusion, a lower colonization was achieved in SL brackets and S. mutans biofilms were susceptible to CHX treatment to both studied brackets.

The effects of essential oil mouthrinses with or without alcohol on plaque and gingivitis: a randomized controlled clinical study

BACKGROUND

The efficacy of several variants of essential oil mouthrinses has been studied extensively. This is the first study to compare the anti-plaque and anti-gingivitis efficacy of two marketed essential oil mouthrinses: one is an alcohol containing mouthrinse and the other one is an alcohol-free mouthrinse.

METHODS

This examiner-blind, parallel-group study randomized subjects to three groups: 1) Mechanical Oral Hygiene (MOH) only; 2) MOH plus Alcohol-Containing essential oil Mouthrinse (ACM); 3) MOH plus Alcohol-Free essential oil Mouthrinse (AFM). Primary endpoint was whole-mouth mean Modified Gingival Index (MGI) at six months. Secondary endpoints included whole-mouth mean MGI at one and three months, and whole-mouth mean Plaque Index (PI) and whole-mouth mean Bleeding Index (BI) at one, three and six months. Safety assessments were conducted at all time points.

RESULTS

A total of 370 subjects were enrolled; 348 subjects completed the study. After six months, subjects using essential oil mouthrinses with or without alcohol showed significant reduction (p < 0.001) in gingivitis (28.2% and 26.7%, respectively) and significant reduction (p < 0.001) in plaque (37.8% and 37.0%, respectively), compared to those performing MOH only. Significant reductions in MGI, PI, and BI (p < 0.001) were observed at one and three months and also at six months for mean BI. No statistically significant differences were observed for all measured indices between ACM and AFM groups at any time point. Both mouthrinses were well tolerated.

CONCLUSIONS

No significant differences were observed in the efficacy of ACM and AFM to reduce plaque and gingivitis, when used in addition to MOH, over six months.

TRIAL REGISTRATION

The trial was registered on clinicaltrials.gov on November 30, 2016. The registration number is NCT02980497 .

The clinical evaluation of Vi-one chlorhexidine mouthwash on plaque-induced gingivitis: A double-blind randomized clinical trial

Background

Chlorhexidine (CHX) is the most effective antiseptic mouthwash to date. Essential oil such as thymol, have inhibitory and biocidal effects a range of bacteria.

Objective

To determine the effect of mouthwash containing CHX and thymol on plaque induced gingivitis.

Methods

This double-blind randomized clinical trial study was performed on 60 patients with plaque induced gingivitis who were randomly divided into two groups: Group I (CHX/thymol mouthwash-Vi-one) and Group II (CHX mouthwash-Behsa). Patients in each group underwent scaling and root planning and polishing, then were educated about BASS-Method brushing, and were recommended Oral-B toothbrushes and Pooneh toothpaste. The two groups were asked to rinse their mouths for 60 seconds twice a day, once in the morning and once at night, after brushing their teeth. Plaque index, gingival index, bleeding index and stain index were evaluated at baseline and 14 days later in Ramfjord teeth. Data analysis was conducted using SPSS version 21. Independent-samples t-test and paired-samples t-test were used for data analysis.

Results

The results showed that plaque index and gingival index significantly reduced in two groups (p<0.001). However, group I was significantly more efficient than group II (p<0.001, p=0.021 respectively). Similar results were observed in terms of bleeding index with the difference that the two groups did not differ significantly from each other (p=0.879). Both groups significantly increased the stain index. No remarkable difference was also observed between the two groups (p=0.754).

Conclusion

Based on the results of this study, we can conclude that the CHX/thymol mouthwash can be offered to patients with dental plaque-induced gingivitis, because it appears to be more effective in controlling dental plaque and gingivitis.

Trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT201602231760N45.

Funding

This study was part of a thesis and research project (Grant No: 9440921) supported and funded by Babol University of Medical Sciences. The authors received no financial support from Behsa pharmaceutical company (Behsa mouthwash manufacturer) or Rojin cosmetic laboratory (Vi-one mouthwash manufacturer) for this study.

Microbiological assessment of effects of clinical mouth rinses on common oral microbes

Dry mouth occurs frequently in aged individuals, as well as in patients who are hospitalized, receiving multiple drugs, undergoing radiation treatment to the head and neck, or wearing a removable denture prosthesis, use of mouth rinse being often an option for relief. In the present study, we performed microbiological assessments of subjects given three different commercially available mouth rinses commonly employed in clinical practice (Peptisal, Biotène, ConCool) to determine their effects. For bacterial clearance in vitro, Peptisal showed the highest level of suppression of oral indigenous bacteria found in both planktonic formations and biofilm. Furthermore, the inhibitory effects of these agents on biofilm formation on acrylic resin plates were examined using scanning electron microscopy. Again, Peptisal proved superior, because acquisition of resistance to antimicrobial peptides by a sensitive microbial strain was rarely observed. We conclude that Peptisal is an effective mouth rinse for clearance of planktonic and biofilm microorganisms present in the oral cavity.

Mouthwashes in the 21st century: a narrative review about active molecules and effectiveness on the periodontal outcomes

INTRODUCTION

Poor oral hygiene is a major risk factor for oral diseases. Regular home-based care is essential to maintain good oral hygiene. In particular, mouthrinses can support conventional tooth brushing in reducing accumulation of oral plaque. Areas covered: The most common molecules contained in mouthrinses (chlorhexidine, essential oils, cetyl pyridinium chloride, triclosan, octeneidine, delmopinol, polyvinylpyrrolidone, hyaluronic acid, natural compounds) are discussed, together with relevant clinical and in vitro studies, focusing on their effects on periodontal health. Currently, chlorhexidine is the most efficacious compound, with both antiplaque and antibacterial activities. Similar results are reported for essential oils and cetyl pyridinium chloride, although with a somewhat reduced efficacy. Considering the adverse effects of chlorhexidine and its time-related characteristics, this molecule may best be indicated for acute/short-term use, while essential oils and cetyl pyridinium chloride may be appropriate for long-term, maintenance treatment. Expert opinion: The literature has not clearly demonstrated which compound is the best for mouthrinses that combine good efficacy and acceptable side effects. Research should focus on substances with progressive antibacterial activity, prompting a gradual change in the composition of oral biofilm and mouthrinses that combine two or more molecules acting synergistically in the mouth.

Cetylpyridinium chloride mouth rinses alleviate experimental gingivitis by inhibiting dental plaque maturation

Oral rinses containing chemotherapeutic agents, such as cetylpyridinium chloride (CPC), can alleviate plaque-induced gingival infections, but how oral microbiota respond to these treatments in human population remains poorly understood. Via a double-blinded, randomised controlled trial of 91 subjects, the impact of CPC-containing oral rinses on supragingival plaque was investigated in experimental gingivitis, where the subjects, after a 21-day period of dental prophylaxis to achieve healthy gingivae, received either CPC rinses or water for 21 days. Within-subject temporal dynamics of plaque microbiota and symptoms of gingivitis were profiled via 16S ribosomal DNA gene pyrosequencing and assessment with the Mazza gingival index. Cetylpyridinium chloride conferred gingival benefits, as progression of gingival inflammation resulting from a lack of dental hygiene was significantly slower in the mouth rinse group than in the water group due to inhibition of 17 gingivitis-enriched bacterial genera. Tracking of plaque α and β diversity revealed that CPC treatment prevents acquisition of new taxa that would otherwise accumulate but maintains the original biodiversity of healthy plaques. Furthermore, CPC rinses reduced the size, local connectivity and microbiota-wide connectivity of the bacterial correlation network, particularly for nodes representing gingivitis-enriched taxa. The findings of this study provide mechanistic insights into the impact of oral rinses on the progression and maturation of dental plaque in the natural human population.

The antibacterial activity of chlorhexidine digluconate against Streptococcus mutans biofilms follows sigmoidal patterns

The aim of this study was to determine the pattern of the antibacterial activity of chlorhexidine digluconate (CHX) against mature Streptococcus mutans biofilms. Streptococcus mutans biofilms were formed on saliva-coated hydroxyapatite discs and then treated with 0-20% CHX, once, three times, or five times (1 min per treatment) during the period of mature biofilm formation (beyond 46 h). After the treatments, the colony-forming unit (CFU) counts of the treated biofilms were determined. The pH values of the spent culture medium were also determined to investigate the change in pH resulting from the antibacterial activity of CHX. The relationships between the concentration of CHX and the CFU counts and the concentration of CHX and culture medium pH, relative to the number of treatments performed, were evaluated using a sigmoidal curve-fitting procedure. The changes in CFU counts and culture medium pH followed sigmoidal curves and were dependent on the concentration of CHX (R² = 0.99). The sigmoidal curves were left-shifted with increasing number of treatments. Furthermore, the culture-medium pH of the treated biofilms increased as their CFU counts decreased. The lowest CHX concentration to increase culture-medium pH above the critical pH also decreased as the number of treatments increased. These results may provide fundamental information for selecting the appropriate CHX concentrations to treat S. mutans biofilms.

Antimicrobial efficiency of mouthrinses versus and in combination with different photodynamic therapies on periodontal pathogens in an experimental study

BACKGROUND AND OBJECTIVE

In the therapy of destructive periodontal disease, chemical antimicrobial agents and increasingly photodynamic therapy (PDT) play an important adjunctive role to standard mechanical anti-infective treatment procedures. However, both antiseptic methods have their shortcomings in terms of eliminating periodontal pathogens. The aim of the study was to compare the antibacterial efficacy of different antiseptic mouthrinses, of a conventional and a new, modified PDT^plus as well as of the different antiseptic mouthrinses combined with either the conventional or the modified PDT^plus against periopathogens.

MATERIAL AND METHODS

Six representative periodontitis-associated bacterial strains were grown for 24 h under anaerobic conditions. After mixing the individual cell pellets they were exposed to 10 different antiseptic mouthrinse formulations: chlorhexidine (0.2%, 0.06%, CHX); CHX + cetylpyridinium chloride (each 0.05%); sodium hypochlorite (0.05%); polyhexanide (0.04%, PHMB1; 0.1%, PHMB2); octenidine dihydrochloride (0.1%); fluoride (250 ppm); essential oils; povidone iodine (10%); and saline (0.9%, NaCl) as control. Furthermore, the bacteria were treated with conventional PDT based on light-emitting diodes and a new modified photodisinfection combining photosensitizer with hydrogen peroxide to PDT^plus also based on light-emitting diodes. In addition to the single treatments, a combined application of antiseptic exposure followed by use of PDT or PDT^plus was performed. The microbial viability was characterized by analyzing colony growth and fluorescence-based vitality proportions.

RESULTS

Nearly all mouthrinses caused a statistically significant growth inhibition. The most effective antiseptics, CHX (0.2%), CHX/cetylpyridinium chloride and octenidine dihydrochloride, inhibited bacterial growth completely. Conventional PDT resulted in moderate reduction of colony growth. The modified PDT^plus achieved maximum antimicrobial effect. The combination of antiseptic exposure and PDT against periopathogens predominantly increased antibacterial efficacy compared to the single applications. The mouthrinse containing essential oil seemed to interfere with PDT.

CONCLUSION

A combination therapy of preceding chemotherapeutical exposure and subsequent photodisinfection may be a more effective and promising antibacterial treatment than single applications of the antiseptic methods. The modified PDT^plus using oxygen-enriched toluidine showed a superior antibacterial effect on periodontal pathogens to conventional PDT and to the majority of the investigated mouthrinses.

Chemical Plaque Control Strategies in the Prevention of Biofilm-associated Oral Diseases

Dental plaque is a biofilm that forms naturally on the surfaces of exposed teeth and other areas of the oral cavity. It is the primary etiological factor for the most frequently occurring oral diseases, such as dental caries and periodontal diseases. Specific, nonspecific, and ecologic plaque hypothesis explains the causation of dental and associated diseases. Adequate control of biofilm accumulation on teeth has been the cornerstone of prevention of periodontitis and dental caries. Mechanical plaque control is the mainstay for prevention of oral diseases, but it requires patient cooperation and motivation; therefore, chemical plaque control agents act as useful adjuvants for achieving the desired results. Hence, it is imperative for the clinicians to update their knowledge in chemical antiplaque agents and other developments for the effective management of plaque biofilm-associated diseases. This article explores the critical analysis of various chemical plaque control strategies and the current trends in the control and prevention of dental plaque biofilm.

Evaluation of toothbrush disinfection via different methods

The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl), a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10). Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal-Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05). The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control). The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

In vitro method for prediction of plaque reduction by dentifrice

An in vitro Particle Based Biofilm (PBB) model was developed to enable high throughput screening tests to predict clinical plaque reduction. Multi-species oral biofilms were cultured from pooled stimulated human saliva on continuously-colliding hydroxyapatite particles. After three days PBBs were saline washed prior to use in screening tests. Testing involved dosing PBBs for 1min followed by neutralization of test materials and rinsing. PBBs were then assayed for intact biofilm activity measured as ATP. The ranking of commercial dentifrices from most to least reduction of intact biofilm activity was Crest ProHealth Clinical Gum Protection, Crest ProHealth, Colgate Total and Crest Cavity Protection. We demonstrated five advantages of the PBB model: 1) the ATP metric had a linear response over ≥1000-fold dynamic range, 2) potential interference with the ATP assay by treatments was easily eliminated by rinsing PBBs with saline, 3) discriminating power was statistically excellent between all treatment comparisons with the negative controls, 4) screening test results were reproducible across four tests, and 5) the screening test produced the same rank order for dentifrices as clinical studies that measured plaque reduction. In addition, 454 pyrosequencing of the PBBs indicated an oral microbial consortium was present. The most prevalent genera were Neisseria, Rothia, Streptococcus, Porphyromonas, Prevotella, Actinomyces, Fusobacterium, Veillonella and Haemophilus. We conclude these in vitro methods offer an efficient, effective and relevant screening tool for reduction of intact biofilm activity by dentifrices. Moreover, dentifrice rankings by the in vitro test method are expected to predict clinical results for plaque reduction.

Essential Oil from Berries of Lebanese Juniperus excelsa M. Bieb Displays Similar Antibacterial Activity to Chlorhexidine but Higher Cytocompatibility with Human Oral Primary Cells

Chlorhexidine (CHX), one of the most effective drugs administered for periodontal treatment, presents collateral effects including toxicity when used for prolonged periods; here, we have evaluated the bactericidal potency and the cytocompatibility of Juniperus excelsa M. Bieb essential oil (EO) in comparison with 0.05% CHX. The EO was extracted from berries by hydrodistillation and components identified by gas chromatography and mass spectrometry. Bacterial inhibition halo analysis, quantitative cell viability 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenyl amino) carbonyl]-2H-tetrazolium hydroxide assay (XTT), and colony forming unit (CFU) count were evaluated against the two biofilm formers Aggregatibacter actinomycetemcomitans and Streptococcus mutans. Finally, cytocompatibility was assessed with human primary gingival fibroblasts (HGF) and mucosal keratinocytes (HK). The resulting EO was mainly composed of monoterpene hydrocarbons and oxygenated monoterpenes. An inhibition halo test demonstrated that both bacteria were sensitive to the EO; XTT analysis and CFU counts confirmed that 10-fold-diluted EO determined a statistically significant (p < 0.05) reduction in bacteria count and viability towards both biofilm and planktonic forms in a comparable manner to those obtained with CHX. Moreover, EO displayed higher cytocompatibility than CHX (p < 0.05). In conclusion, EO exhibited bactericidal activity similar to CHX, but a superior cytocompatibility, making it a promising antiseptic alternative to CHX.

Impact of an anticaries mouthrinse on in vitro remineralization and microbial control

Objective. The objective of this research was to evaluate the caries control potential of a new fluoride mouthrinse that also contained antimicrobial agents and a biofilm disrupting agent using different in vitro models. Methods. Four in vitro studies were conducted to assess the performance of this three pronged approach to caries control: (1) traditional enamel fluoride uptake, (2) surface microhardness study using pH cycling model and subsequent fluoride uptake, (3) a salivary biofilm flow-through study to determine the anti-microbial activity, and (4) a single species biofilm model measuring effect on biofilm matrix disruption. Results. The data showed that a LISTERINE rinse with fluoride, essential oils and xylitol was superior in promoting enamel fluoride uptake and in enhancing antimicrobial activity over traditional commercially available fluoridated products. An increase of the surface microhardness was observed when the LISTERINE rinse was used in combination with fluoridated toothpaste versus the fluoridated toothpaste alone. Finally, it was demonstrated that xylitol solutions disrupted and reduced the biovolume of biofilm matrix of mature Streptococcus mutans. Conclusion. These in vitro studies demonstrated that a fluoride mouthrinse with antimicrobial agent and biofilm matrix disrupting agent provided multifaceted and enhanced anti-caries efficacy by promoting remineralization, reducing acidogenic bacteria and disrupting biofilm matrix.

Efficacy of a new mouth rinse formulation based on 0.07% cetylpyridinium chloride in the control of plaque and gingivitis: a 6-month randomized clinical trial

AIM

To assess the efficacy of a 0.07% cetylpyridinium chloride (CPC) mouth rinse in the control of plaque and gingival inflammation during a 6-month period.

MATERIAL AND METHODS

Adult subjects with moderate gingivitis were selected [≥40% bleeding on marginal probing (BOMP)]. After retrieving microbiological samples and evaluating the clinical parameters (plaque, BOMP and stain indexes), a professional prophylaxis was performed and subjects were randomly assigned to the test (CPC mouth rinse) or to the placebo group. Subjects were re-assessed after 3 and 6 months.

RESULTS

A total of 67 patients (35 test, 32 placebo) were included in the analysis. At 6 months, intra-group significant plaque reductions were observed in the test group (0.691, p < 0.001), but not in the placebo (0.181, p = 0.653). At 6 months, the mean BOMP values were lower in the test group (p = 0.052). Changes between baseline and 6 months were significantly higher in the test group both for plaque (p = 0.002) and BOMP (p = 0.037) when compared with the placebo. A microbiological impact was observed in the test group, especially for Prevotella intermedia.

CONCLUSION

The evaluated 0.07% CPC-based mouth rinse, used three times per day adjunctively to mechanical tooth cleaning, prevents plaque accumulation and gingival inflammation, as compared to the placebo, for at least 6 months.

A high-throughput microfluidic dental plaque biofilm system to visualize and quantify the effect of antimicrobials

OBJECTIVES

Few model systems are amenable to developing multi-species biofilms in parallel under environmentally germane conditions. This is a problem when evaluating the potential real-world effectiveness of antimicrobials in the laboratory. One such antimicrobial is cetylpyridinium chloride (CPC), which is used in numerous over-the-counter oral healthcare products. The aim of this work was to develop a high-throughput microfluidic system that is combined with a confocal laser scanning microscope (CLSM) to quantitatively evaluate the effectiveness of CPC against oral multi-species biofilms grown in human saliva.

METHODS

Twenty-four-channel BioFlux microfluidic plates were inoculated with pooled human saliva and fed filter-sterilized saliva for 20 h at 37°C. The bacterial diversity of the biofilms was evaluated by bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). The antimicrobial/anti-biofilm effect of CPC (0.5%-0.001% w/v) was examined using Live/Dead stain, CLSM and 3D imaging software.

RESULTS

The analysis of biofilms by bTEFAP demonstrated that they contained genera typically found in human dental plaque. These included Aggregatibacter, Fusobacterium, Neisseria, Porphyromonas, Streptococcus and Veillonella. Using Live/Dead stain, clear gradations in killing were observed when the biofilms were treated with CPC between 0.5% and 0.001% w/v. At 0.5% (w/v) CPC, 90% of the total signal was from dead/damaged cells. Below this concentration range, less killing was observed. In the 0.5%-0.05% (w/v) range CPC penetration/killing was greatest and biofilm thickness was significantly reduced.

CONCLUSIONS

This work demonstrates the utility of a high-throughput microfluidic-CLSM system to grow multi-species oral biofilms, which are compositionally similar to naturally occurring biofilms, to assess the effectiveness of antimicrobials.

Oil Essential Mouthwashes Antibacterial Activity against Aggregatibacter actinomycetemcomitans: A Comparison between Antibiofilm and Antiplanktonic Effects

The aim of this work is to determine the antibacterial activity of three marketed mouthwashes on suspended and sessile states of Aggregatibacter actinomycetemcomitans. The efficacy of two commonly used products in clinical practice, containing essential oils as active ingredients (menthol, thymol, methyl salicylate, and eucalyptol) in association with or without alcohol, has been evaluated in comparison with a chlorhexidine-based mouthwash. The microtiter plate assay, in order to obtain a spectrophotometric measurement of bacterial responses at growing dilutions of each antiseptic, was used for the study. The analysis revealed that a good antibacterial activity is reached when the abovementioned mouthwashes were used at concentration over a 1/24 dilution and after an exposure time of 30 seconds at least. In conclusion, the alcoholic mouthwash appears to have a better biofilm inhibition than its antiplanktonic activity while the nonalcoholic product demonstrates an opposite effect with a better antiplanktonic behavior.

Oil Essential Mouthwashes Antibacterial Activity against Aggregatibacter actinomycetemcomitans: A Comparison between Antibiofilm and Antiplanktonic Effects

The aim of this work is to determine the antibacterial activity of three marketed mouthwashes on suspended and sessile states of Aggregatibacter actinomycetemcomitans. The efficacy of two commonly used products in clinical practice, containing essential oils as active ingredients (menthol, thymol, methyl salicylate, and eucalyptol) in association with or without alcohol, has been evaluated in comparison with a chlorhexidine-based mouthwash. The microtiter plate assay, in order to obtain a spectrophotometric measurement of bacterial responses at growing dilutions of each antiseptic, was used for the study. The analysis revealed that a good antibacterial activity is reached when the abovementioned mouthwashes were used at concentration over a 1/24 dilution and after an exposure time of 30 seconds at least. In conclusion, the alcoholic mouthwash appears to have a better biofilm inhibition than its antiplanktonic activity while the nonalcoholic product demonstrates an opposite effect with a better antiplanktonic behavior.

Validation of ATP bioluminescence as a tool to assess antimicrobial effects of mouthrinses in an in vitro subgingival-biofilm model

Objectives. The aim of this investigation was to evaluate whether the adenosine triphosphate (ATP) bioluminescence method is an appropriate tool to assess the efficacy of antiseptic mouthrinses in terms of quantitative reductions of total viable microbial counts in mixed biofilm populations in vitro. Study Design. Three mouthrinses, containing respectively, chlorhexidine and cetylpyridinium chloride (CHX/CPC), essential oils (EO) and amine fluoride/stannous fluoride (AFSF), as well as Phosphate Buffered Saline (PBS) used as control, were tested in an in vitro static biofilm model by ATP bioluminescence and compared to culture method. Biofilms were grown on saliva-coated hydroxyapatite disks for 72 hours and then exposed for 1 minute to the mouthrinse or control by immersion. The antibacterial effect of the rinses was tested by analysis of variance. The reliability of the ATP bioluminescence method was assessed by calculating the Pearson correlation coefficients when compared to the viable cell counts obtained by culture. Results. Using ATP bioluminescence, the antimicrobial activity of the tested mouthrinses was demonstrated when compared to the PBS control. The ATP bioluminescence values were significantly correlated (0.769, p<0.001) to the viable cell counts. CHX/CPC and AFSF showed similar antimicrobial activity, although AFSF had a less homogeneous effect, being both more effective than the EO rinse. Conclusion. ATP bioluminescence viability testing may be considered a useful tool to assess the in vitro efficacy of antibacterial compounds. In the proposed model, CHX/CPC and AFSF containing mouthrinses demonstrated superior antimicrobial activity, as compared to EO rinses, in a multispecies biofilm model.

Key words:Biofilm, ATP bioluminescence,mouthrinse, essential oils, chlorhexidine, amine fluoride/stannous fluoride.

Application of an active attachment model as a high-throughput demineralization biofilm model

OBJECTIVES

To investigate the potential of an active attachment biofilm model as a high-throughput demineralization biofilm model for the evaluation of caries-preventive agents.

METHODS

Streptococcus mutans UA159 biofilms were grown on bovine dentine discs in a high-throughput active attachment model. Biofilms were first formed in a medium with high buffer capacity for 24h and then subjected to various photodynamic therapies (PACT) using the combination of Light Emitting Diodes (LEDs, Biotable(®)) and Photogem(®). Viability of the biofilms was evaluated by plate counts. To investigate treatment effects on dentine lesion formation, the treated biofilms were grown in a medium with low buffer capacity for an additional 24h. Integrated mineral loss (IML) and lesion depth (LD) were assessed by transversal microradiography. Calcium release in the biofilm medium was measured by atomic absorption spectroscopy.

RESULTS

Compared to the water treated control group, significant reduction in viability of S. mutans biofilms was observed when the combination of LEDs and Photogem(®) was applied. LEDs or Photogem(®) only did not result in biofilm viability changes. Similar outcomes were also found for dentine lesion formation. Significant lower IML and LD values were only found in the group subjected to the combined treatment of LEDs and Photogem(®). There was a good correlation between the calcium release data and the IML or LD values.

CONCLUSIONS

The high-throughput active attachment biofilm model is applicable for evaluating novel caries-preventive agents on both biofilm and demineralization inhibition. PACT had a killing effect on 24h S. mutans biofilms and could inhibit the demineralization process.

Quantification of vital adherent Streptococcus sanguinis cells on protein-coated titanium after disinfectant treatment

The quantification of vital adherent bacteria is challenging, especially when efficacy of antimicrobial agents is to be evaluated. In this study three different methods were compared in order to quantify vital adherent Streptococcus sanguinis cells after exposure to disinfectants. An anaerobic flow chamber model accomplished initial adhesion of S. sanguinis on protein-coated titanium. Effects of chlorhexidine, Betadine®, Octenidol®, and ProntOral® were assessed by quantifying vital cells using Live/Dead BacLight™, conventional culturing and isothermal microcalorimetry (IMC). Results were analysed by Kruskal-Wallis one-way analysis of variance. Live/dead staining revealed highest vital cell counts (P < 0.05) and demonstrated dose-dependent effect for all disinfectants. Microcalorimetry showed time-delayed heat flow peaks that were proportioned to the remaining number of viable cells. Over 48 h there was no difference in total heat between treated and untreated samples (P > 0.05), indicating equivalent numbers of bacteria were created and disinfectants delayed growth but did not eliminate it. In conclusion, contrary to culturing, live/dead staining enables detection of cells that may be viable but non-cultivable. Microcalorimetry allows unique evaluation of relative disinfectant effects by quantifying differences in time delay of regrowth of remaining vital cells.

Clinical and antimicrobial evaluation of a mouthwash and toothpaste for xerostomia: a randomized, double-blind, crossover study

OBJECTIVES

Specific toothpaste and mouthwash for xerostomia based on triclosan, fluoride, and mineral salts were studied in order to evaluate their efficacy in improving the quality of life as well as their in vitro antimicrobial action.

MATERIALS AND METHODS

30 patients with dry mouth and hyposalivation confirmed by sialometry were included in a randomized, double-blind, crossover study, during two weeks for each experimental phase. Dryness and oral comfort, difficulty in speaking, chewing, swallowing and using dental prostheses, as well as taste and sleep disorders were evaluated. Values of minimal biocidal and minimal inhibitory concentrations of both products against microorganisms that often cause oral disorders in these patients were determined and compared.

RESULTS

The use of the mouthwash and toothpaste studied improved the dry mouth symptoms, whilst no significant differences when compared with the salivary enzyme substitutes were observed. The test products showed, in general, a higher biocidal and inhibitory action than the control products, with particularly noteworthy action against cariogenic bacteria.

CONCLUSIONS

The use of a toothpaste and mouthwash based on triclosan, fluoride, gingival revitalizers and mineral salts, improves the quality of life of patients suffering xerostomia.