Comparative antimicrobial activity of an essential oil and an amine fluoride/stannous fluoride mouthrinse in vitro

Inhibitory Effects of Chrysanthemum boreale Essential Oil on Biofilm Formation and Virulence Factor Expression of Streptococcus mutans

The aim of the study was to evaluate the antibacterial activity of essential oil extracted from Chrysanthemum boreale (C. boreale) on Streptococcus mutans (S. mutans). To investigate anticariogenic properties, and bacterial growth, acid production, biofilm formation, bacterial adherence of S. mutans were evaluated. Then gene expression of several virulence factors was also evaluated. C. boreale essential oil exhibited significant inhibition of bacterial growth, adherence capacity, and acid production of S. mutans at concentrations 0.1-0.5 mg/mL and 0.25-0.5 mg/mL, respectively. The safranin staining and scanning electron microscopy results showed that the biofilm formation was also inhibited. The result of live/dead staining showed the bactericidal effect. Furthermore, real-time PCR analysis showed that the gene expression of some virulence factors such as gtfB, gtfC, gtfD, gbpB, spaP, brpA, relA, and vicR of S. mutans was significantly decreased in a dose dependent manner. In GC and GC-MS analysis, seventy-two compounds were identified in the oil, representing 85.42% of the total oil. The major components were camphor (20.89%), β-caryophyllene (5.71%), α-thujone (5.46%), piperitone (5.27%), epi-sesquiphellandrene (5.16%), α-pinene (4.97%), 1,8-cineole (4.52%), β-pinene (4.45%), and camphene (4.19%). These results suggest that C. boreale essential oil may inhibit growth, adhesion, acid tolerance, and biofilm formation of S. mutans through the partial inhibition of several of these virulence factors.

Evaluation of antimicrobial effects of commercial mouthwashes utilized in South Korea

Streptococcus mutans is frequently associated with dental caries. Bacterial fermentation of food debris generates an acidic environment on the tooth surface, ultimately resulting in tooth deterioration. Therefore, various mouthwashes have been used to reduce and prevent Streptococcus mutans. The aim of this study was to evaluate the antimicrobial activities of 4 commercial mouthwashes and those of 10% and 20% ethanol solutions (formula A, B, C, D, E and F) against Streptococcus mutans using biofilm and planktonic methods. The range of reduction in the viable cell count of Streptococcus mutans as estimated by the biofilm and planktonic methods was 0.05-5.51 log (P ≤ 0.01) and 1.23-7.51 log (P ≤ 0.001) compared with the negative control, respectively, indicating that the planktonic method had a stronger antibacterial effect against S. mutans. Among the tested formulations, formula A(Garglin regular^Ⓡ mouthwash) was the most effective against Streptococcus mutans (P ≤ 0.001). [BMB Reports 2015; 48(1): 42-47]

Effectiveness of an alcohol-free essential oil-containing mouthwash in institutionalised elders receiving long-term care: a feasibility study

OBJECTIVES

To conduct a feasibility study on investigating the effectiveness of an alcohol-free essential oil mouthwash (AF-EOMW) to reduce plaque accumulation and oral pathogen levels in institutionalised elders receiving long-term care and to obtain preliminary results.

BACKGROUND

Although simple, cost-effective strategies to improve oral hygiene in seniors such as the use of mouthwashes have been shown to reduce the risks of respiratory diseases, little information is available on the feasibility of implementing these measures.

METHODS

Twenty-five elderly participants with significant loss of autonomy were initially recruited and divided into two groups. A test group rinsed with an AF-EOMW twice a day, and a control group rinsed with tap water. Data on demographic characteristics, dental history and tobacco use were collected from a questionnaire. Problems encountered during recruitment and data collection were documented. Plaque index, denture cleanliness and salivary levels of several pathogens were measured at three time points: baseline (T0 ), day 22 (T1 ) and day 45 (T2 ).

RESULTS

Eighteen participants completed the study. Several problems were encountered during recruitment and execution of the study protocol. No significant differences in clinical or microbiological measures were found between the test group and controls at three time points (p > 0.05).

CONCLUSION

This pilot study shows that, if sufficient logistical and financial resources are available, it is feasible to conduct randomised clinical trials in a seniors' facility. The use of an AF-EOMW to improve oral hygiene in seniors was not found to be superior to tap water. However, larger controlled clinical studies are needed to confirm these results.

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.

Kaurenoic Acid from Aralia continentalis Inhibits Biofilm Formation of Streptococcus mutans

We isolated a single chemical compound from A. continentalis and identified it to be kaurenoic acid (KA) and investigated the influence of anticariogenic properties. Inhibitory effects of KA on cariogenic properties such as growth, acid production, biofilm formation, and the adherence of S. mutans were evaluated. Furthermore, real-time PCR analysis was performed to evaluate the influence of KA on the genetic expression of virulence factors. KA significantly inhibited the growth and acid production of S. mutans at 2–4 μg/mL and 4 μg/mL of KA, respectively. Furthermore, the adherence onto S-HAs was inhibited at 3-4 μg/mL of KA and biofilm formation was significantly inhibited when treated with 3 μg/mL KA and completely inhibited at 4 μg/mL. Also, the inhibitory effect of KA on biofilm formation was confirmed by SEM. In confocal laser scanning microscopy, bacterial viability gradually decreased by KA in a dose dependent manner. Real-time PCR analysis showed that the expressions of gtfB, gtfC, gbpB, spaP, brpA, relA, and vicR were significantly decreased in S. mutans when it was treated with KA. These results suggest that KA from A. continentalis may be a useful agent for inhibiting the cariogenic properties of S. mutans.

Anticariogenic Properties of the Extract ofCyperus rotundus

Streptococcus mutans (S. mutans) is known as the causative bacteria in the formation of dental plaque and dental caries. The aim of this experiment was to investigate the effects of Cyperus rotundus (C. rotundus) tuber extract on the growth, acid production, adhesion, and water-insoluble glucan synthesis of S. mutans. The growth and acid production were reduced by the extract of C. rotundus in a dose dependent manner. The extract of C. rotundus markedly inhibited the adherence of S. mutans to saliva-coated hydroxyapatite beads (HAs). The adherence was repressed by more than 50% at the concentration of 0.5 mg/ml of the extract and complete inhibition was observed at the concentration of 4 mg/ml of the extract. On the activity of glucosyltransferase (GTFase) which synthesizes water-insoluble glucan from sucrose, the extract of C. rotundus showed more than 10% inhibition at a concentration of 2 mg/ml. These results suggest that C. rotundus may inhibit cariogenic properties of S. mutans. Further studies are necessary to clarify the active constituents of C. rotundus responsible for such biomolecular activities.

Inhibitory effect of Aralia continentalis on the cariogenic properties of Streptococcus mutans

ETHNOPHARMACOLOGICAL RELEVANCE

Aralia continentalis has been used in traditional Korean medicine for dental diseases such as toothache, dental caries, periodontal disease and gingivitis, and also has been used for neuralgia, analgesia, sweating, and as an antirheumatic.

AIM OF THE STUDY

The present study was designed to investigate the inhibitory effect of Aralia continentalis extract on cariogenic properties of Streptococcus mutans, which is one of the most important bacteria in the formation of dental caries and dental plaque.

MATERIALS AND METHODS

The inhibitory effects of Aralia continentalis extract on the growth, acid production, water-insoluble glucan synthesis, and adhesion were investigated in Streptococcus mutans. The biofilm formation of Streptococcus mutans was determined by scanning electron microscopy (SEM) and safranin staining.

RESULTS

The ethanol extract of Aralia continentalis showed concentration dependent inhibitory activity on the growth of Streptococcus mutans and significant inhibition of acid production at the concentrations of 0.25, 0.5, 1, 2 and 4 mg/ml compared to the control group. The synthesis of water-insoluble glucan by glucosyltransferase (GTFase) was decreased in the presence of 0.5-4 mg/ml of the extract of Aralia continentalis. The extract markedly inhibited Streptococcus mutans adherence to saliva-coated hydroxyapatite beads (S-HAs). The extract of Aralia continentalis has an inhibitory effect on the formation of Streptococcus mutans biofilms at the concentrations higher than 2mg/ml.

CONCLUSIONS

These results suggest that Aralia continentalis may inhibit cariogenic properties of Streptococcus mutans, and also may support the scientific rationale that native inhabitants used the extract for the treatment of dental diseases.

Susceptibility to various oral antiseptics of Porphyromonas gingivalis W83 within a biofilm

The origin of chronic periodontal disease is strongly related to the nature and physiology of the subgingival bacterial biofilm, of which Porphyromonas gingivalis is a main protagonist. This study was conducted in vitro, to test the susceptibility of the W83 strain of P gingivalis to several oral antiseptics, bearing in mind its mode of growth as biofilm. To this end, the investigators inoculated a brain-heart infusion broth with Streptococcus gordonii, to which P gingivalis was added before perfusion for 7 d via a closed circuit containing a modified Robbins device. Then, various antiseptics were perfused through the circuit over 30 min, and their bactericidal effects were evaluated after culture by comparison of the mean proportion of bacteria killed. The average proportion of P gingivalis W83 killed after 15 min of contact with antiseptics was 90.51% (+/-4.78) for chlorhexidine 0.2%, 89.87% (+/-6.58) for povidone-iodine 1%, and 98.6% (+/-0.86) for Listerine (McNeil-PPC, Inc., Morris Plains, NJ). After 30 min of contact, survival of P gingivalis was nil, irrespective of the antimicrobial agent used. Preliminary results show that antiseptic mouth rinses, when used in pure concentrations in the traditional way, are effective in killing P gingivalis W83 within a biofilm. Furthermore, in light of these experiments, it appears that the best results are obtained when Listerine is used; however, new trials should be conducted to confirm this observation.

Saussurea lappa inhibits the growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans

In the present study, inhibitory effects of the ethanol extract of Saussurea lappa (S. lappa) on the growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans (S. mutans) were examined. The growth and acid production of Streptococcus mutans were inhibited by the presence of ethanol extract of Saussurea lappa (0.5-4 mg/ml) significantly. The ethanol extract of Saussurea lappa (0.25-4 mg/ml) also significantly lowered the adherence of Streptococcus mutans in a dose dependent manner. In water-insoluble glucan synthesis assay, 2-4 mg/ml of the ethanol extract of Saussurea lappa significantly inhibited the formation of water-insoluble glucan. These results suggest that Saussurea lappa may inhibit the caries-inducing properties of Streptococcus mutans. Further studies are necessary to clarify the active constituents of Saussurea lappa responsible for such biomolecular activities.

Asarum sieboldii extracts attenuate growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans

Asarum sieboldii has been used in traditional folk medicine to treat dental caries and periodontal disease. In the present study, we investigated the inhibitory effect of the ethanol and aqueous extracts of A. sieboldii on the growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans. The ethanol and aqueous extracts of A. sieboldii inhibited the growth and acid production of S. mutans. In the bacterial adherence assay, the ethanol and aqueous extracts of A. sieboldii significantly lowered the adherence of S. mutans. We also found that the ethanol and aqueous extracts of A. sieboldii significantly inhibited the synthesis of water-insoluble glucan by crude glucosyltransferase. These results suggest that A. sieboldii extracts may inhibit the caries-inducing properties of S. mutans. Further studies are necessary to clarify the active constituents of A. sieboldii extracts responsible for such biomolecular activities.

How to select the right mouthrinses in periodontal prevention and therapy. Part I. Test systems and clinical investigations

The use of mouthrinses is increasing, especially as adjuncts to the daily mechanical oral hygiene. Different test systems may and can be used to test their antibacterial and clinical effects: bacteriology in vitro, substantivity in vivo, 4-day plaque re-growth, experimental gingivitis and long-term use. The plaque re-growth investigations of a few days are not only of limited use but may also be dangerous because often too extensive conclusions have been drawn from their design. The 'gold standard' test is the experimental gingivitis model to reveal the antiplaque as well as the antigingivitis effects of any mouthrinse preparation during 3 weeks. The last kind of investigations are of several months' duration, where the substances are used as supplements to mechanical oral hygiene measures.

In vivo antimicrobial effectiveness of an essential oil-containing mouth rinse 12 h after a single use and 14 days' use

OBJECTIVES

Two studies were conducted to determine the antimicrobial effect of rinsing with an essential oil-containing mouth rinse 12 h after a single rinse and 12 h after 2 weeks of twice daily rinsing, during the daytime and overnight.

MATERIALS AND METHODS

These studies utilized a randomized, double-blind, controlled crossover design. Following baseline sampling of bacteria from supragingival plaque and the dorsum of the tongue, subjects began twice-daily rinsing with either an essential oil mouth rinse containing 0.09% zinc chloride (Tartar Control Listerine Antiseptic) or a negative control rinse. Bacterial sampling was repeated 12 h after the first rinse, and again 12 h after the final rinse 14 days later. The sampling schedule was adjusted according to whether the study was investigating daytime or overnight activity. Samples were plated on Schaedlers medium (total anaerobes), Schaedlers Nalidixic/Vancomycin medium (Gram-negative anaerobes), and OOPS medium (volatile sulphur compound (VSC)-producing organisms). Inter-group log10 transformed colony-forming units/ml counts from samples of supragingival plaque and tongue swabs on each of the three media were compared by analysis of covariance.

RESULTS

The mean bacterial counts in subjects using the essential oil mouth rinse were significantly lower (p< or =0.005) than mean counts in subjects using the control rinse in all the comparisons, i.e., tongue and supragingival plaque samples on each of three media at two sampling periods in the daytime and overnight study, respectively. Mean bacterial count percent reductions for plaque samples ranged from 56.3 to 95.3; percent reductions for tongue samples ranged from 61.1 to 96.1. There was a trend to higher reductions after 14 days' rinsing than after the initial rinse.

CONCLUSION

Rinsing with the essential oil mouth rinse can have long-lasting effects in reducing anaerobic bacteria overall as well as Gram-negative anaerobes and VSC-producing bacteria. The significant reductions in numbers of these bacteria produced by the essential oil mouth rinse, both in plaque and on the dorsum of the tongue, can play a key role in explaining the essential oil mouth rinse's effectiveness in reducing supragingival plaque and gingivitis as well as its effectiveness in controlling intrinsic oral malodor over prolonged periods.

Effect of Powerdental on caries-inducing properties of Streptococcus mutans and TNF-alpha secretion from HMC-1 cells

We studied the inhibitory effect of Powerdental on the growth and acid production of Streptococcus mutans as well as secretion of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha). The growth of Streptococcus mutans was reduced by the presence of the Powerdental (1 mg/ml) and NaCl (1 mg/ml) significantly, and the positive control group (1% NaF) also exhibited a significant antibacterial activity. The decrease of pH was significantly inhibited in the presence of Powerdental (1 mg/ml) compared to the control group. The decrease in pH was also inhibited in the presence of positive control (1% NaF), but the bamboo salt alone did not show inhibitory activity. We also found that Powerdental (0.01 mg/ml) inhibited significantly the secretion of TNF-alpha with 46.5+/-0.2% from human mast cells. Our results suggest that Powerdental contributes to the prevention or treatment of periodontitis and other oral diseases or inflammatory diseases.

Does professional preventive care benefit from additional subgingival irrigation?

The effect of an oral irrigator (Water Pik, Intersante) with a subgingival tip (Pik Pocket Subgingival Tip, Intersante) in the reduction of gingivitis was investigated in a single-blind three-group study involving 45 volunteers (age 46.2+/-10.2). All volunteers (inclusion criteria: gingivitis or a superficial periodontitis) were examined and underwent professional tooth cleaning at the first appointment. They were then randomly distributed in three groups: one group used the irrigator with the subgingival tip once daily with just tap water, in addition to their regular oral hygiene; another group also used an herbal-based mouth rinse (Parodontax, GlaxoSmithkline) in the water of the irrigator; a third group did not use an irrigator or any irrigant and therefore served as control. All groups received professional oral care education at each appointment. The investigation period was 3 months. At baseline and after 4, 8, and 12 weeks, the plaque index (PI, scores 0-5), gingival index (GI, scores 0-3), bleeding index (BI scores 0-5), and sulcus fluid flow rate (SFFR, Periotron 6000) at the Ramfjord teeth were scored. At baseline and after 3 months, the probing depth (millimeters) was measured at six surfaces of all teeth. A significant reduction in BI, PI, GI, probing depth, and SFFR was observed within 3 months. With all volunteers, however, there was no statistically significant difference ( p>/=0.05, Wilcoxon-test, SAS 6.04) between the three groups at any time. The additional use of the Water Pik irrigator with the Pik Pocket subgingival irrigation device with or without an herbal mouth rinse showed no clinical benefit over professional education in oral hygiene alone.

The role of therapeutic antimicrobial mouthrinses in clinical practice: control of supragingival plaque and gingivitis

BACKGROUND

Although mechanical plaque control methods have the potential to maintain adequate levels of oral hygiene, clinical experience and population-based studies demonstrate that such methods are not being employed sufficiently by large numbers of the population. The need for additional help in controlling bacterial plaque provides the rationale for patients' using antimicrobial mouthrinses as adjuncts to their mechanical oral hygiene regimens.

TYPES OF STUDIES REVIEWED

The author presents an overview of the types of studies used to support the effectiveness of antiplaque and antigingivitis mouthrinses, ranging from laboratory studies to six-month clinical trials. He discusses plaque as an example of a biofilm and the implications of recent research on the nature of biofilms with respect to the nature of the evidence that can be used to demonstrate clinical effectiveness.

CONCLUSIONS

The safety and clinical effectiveness of antiplaque and antigingivitis antimicrobial mouthrinses are best determined using prospective, randomized clinical trials conducted in accordance with ADA guidelines.

CLINICAL IMPLICATIONS

The adjunctive use of antimicrobial mouthrinses can provide significant benefits to patients who cannot maintain adequate levels of plaque and gingivitis control through mechanical methods alone. Dentists should recommend products that have proven clinical activity as demonstrated using generally accepted safety and effectiveness criteria.

Comparative antimicrobial activities of antiseptic mouthrinses against isogenic planktonic and biofilm forms of Actinobacillus actinomycetemcomitans

BACKGROUND

Bacteria contained in biofilms have been shown to have a decreased susceptibility to antimicrobial agents compared to those in planktonic form. Thus, in vitro biofilm models have been developed for screening oral antimicrobial formulations in an effort to produce findings more predictive of clinical activity. This study compared the antimicrobial activity of three mouthrinse formulations when tested against isogenic strains of Actinobacillus actinomycetemcomitans (Aa), one of which was a clinical isolate which forms tenacious biofilms in vitro and the other of which was a spontaneous variant which always grows planktonically.

METHOD

Biofilm-forming Aa strains CU1000 and NJ4300, obtained as clinical isolates, and their respective spontaneous planktonic variants, CU1060 and NJ4350, were grown under standard laboratory conditions and exposed for 15 s to either a negative control (phosphate buffered saline [PBS]), an essential-oil containing mouthrinse (Listerine Antiseptic [LA]), an amine fluoride/stannous fluoride-containing mouthrinse (Meridol [M]), or a triclosan and PVM/MA copolymer-containing mouthrinse (Plax [P]). The cells were then washed, serially diluted, plated, and incubated for enumeration of viable bacteria. Colony-forming units (CFU)/ml were log10 transformed and the mouthrinse groups were compared to the PBS group using analysis of variance.

RESULTS

All 3 mouthrinses produced statisically significant 99.99% reductions (p< or =0.0001) in both planktonic strains compared to the PBS control. Effects on the biofilm forms of the organisms were more variable. Exposure to LA produced statistically significant (p< or =0.0001) reductions in strains CU1000 and NJ4300 of 98.20% and 96.47%, respectively, compared to PBS. M and P produced much smaller reductions which were not statistically significant.

CONCLUSIONS

The results of this study, in which antimicrobial mouthrinses were tested against biofilm-forming and planktonic strains of the same organism, provide a clear demonstration of the resistance to antimicrobial agents conferred by biofilm formation and provide additional support for employing tests using biofilms to more accurately assess the relative activities of antiplaque agents in vitro.

In vitro effect of oral antiseptics on human immunodeficiency virus-1 and herpes simplex virus type 1

AIM

The antiviral effectiveness of widely used commercial mouthrinses has not been well studied. A project was undertaken to evaluate and compare the in vitro antiviral effectiveness of essential oil-containing mouthrinses (LA & TLA) and chlorhexidine mouthrinses (PX & CHX) on 2 different enveloped viruses, human immunodeficiency virus (HIV-1) and Herpes simplex virus (HSV-1) McIntyre strain.

METHOD

HIV-1(89.6) (1x10(5)/ml) and HSV-1 (1x10(6)/ml) in RPMI-1640 medium were treated with two commercially available forms of LA & TLA (tartar control LA), and 2 formulations of chlorhexidine [(PX), 0.12% chlorhexidine & (CHX), 0.2% chlorhexidine] for 30 sec. The antiviral effect was estimated by inhibition of the syncytia formation or the cytopathic effect (CPE) for HIV-1 on MT-2 cells and by inhibition of the plaque formation for HSV-1 on Vero cell monolayers.

RESULTS

Undiluted LA, TLA, PX and CHX completely inhibited both HIV-189.6 and HSV-1 McIntyre strain. PX and CHX inhibited HIV-1 up to 1:4 dilution, whereas, LA and TLA inhibited HSV-1 up to 1:2 dilution. The antiviral effects of LA and TLA were found to be similar and also the antiviral effect of PX and CHX were also found to be comparable.

CONCLUSIONS

The methods used in this investigation allow easy and reproducible evaluations of antiviral efficacy. The anti-HIV-1 and anti-HSV-1 effects of LA, TLA, PX and CHX as evidenced in our in vitro study suggest that we should investigate potential in vivo effects during the use of essential oil-containing or chlorhexidine containing products when used by patients as mouthrinses. If the clinical studies confirm the in vitro data, pre-procedural use by clinicians may be beneficial in reducing viral contamination of bio-aerosols during the delivery of dental care.