In vitro anti-Helicobacter pylori activity and antivirulence activity of cetylpyridinium chloride

The primary treatment method for eradicating Helicobacter pylori (H. pylori) infection involves the use of antibiotic-based therapies. Due to the growing antibiotic resistance of H. pylori, there has been a surge of interest in exploring alternative therapies. Cetylpyridinium chloride (CPC) is a water-soluble and nonvolatile quaternary ammonium compound with exceptional broad-spectrum antibacterial properties. To date, there is no documented or described specific antibacterial action of CPC against H. pylori. Therefore, this study aimed to explore the in vitro activity of CPC against H. pylori and its potential antibacterial mechanism. CPC exhibited significant in vitro activity against H. pylori, with MICs ranging from 0.16 to 0.62 μg/mL and MBCs ranging from 0.31 to 1.24 μg/mL. CPC could result in morphological and physiological modifications in H. pylori, leading to the suppression of virulence and adherence genes expression, including flaA, flaB, babB, alpA, alpB, ureE, and ureF, and inhibition of urease activity. CPC has demonstrated in vitro activity against H. pylori by inhibiting its growth, inducing damage to the bacterial structure, reducing virulence and adherence factors expression, and inhibiting urease activity.

Antimicrobial cetylpyridinium chloride causes functional inhibition of mitochondria as potently as canonical mitotoxicants, nanostructural disruption of mitochondria, and mitochondrial Ca2+ efflux in living rodent and primary human cells

People are exposed to high concentrations of antibacterial agent cetylpyridinium chloride (CPC) via food and personal care products, despite little published information regarding CPC effects on eukaryotes. Here, we show that low-micromolar CPC exposure, which does not cause cell death, inhibits mitochondrial ATP production in primary human keratinocytes, mouse NIH-3T3 fibroblasts, and rat RBL-2H3 immune mast cells. ATP inhibition via CPC (EC50 1.7 μM) is nearly as potent as that caused by canonical mitotoxicant CCCP (EC50 1.2 μM). CPC inhibition of oxygen consumption rate (OCR) tracks with that of ATP: OCR is halved due to 1.75 μM CPC in RBL-2H3 cells and 1.25 μM in primary human keratinocytes. Mitochondrial [Ca2+] changes can cause mitochondrial dysfunction. Here we show that CPC causes mitochondrial Ca2+ efflux from mast cells via an ATP-inhibition mechanism. Using super-resolution microscopy (fluorescence photoactivation localization) in live cells, we have discovered that CPC causes mitochondrial nanostructural defects in live cells within 60 min, including the formation of spherical structures with donut-like cross section. This work reveals CPC as a mitotoxicant despite widespread use, highlighting the importance of further research into its toxicological safety.

VesiX cetylpyridinium chloride is rapidly bactericidal and reduces uropathogenic Escherichia coli bladder epithelial cell invasion in vitro

Management of urinary tract infection (UTI) in postmenopausal women can be challenging. The recent rise in resistance to most of the available oral antibiotic options together with high recurrence rate in postmenopausal women has further complicated treatment of UTI. As such, intravesical instillations of antibiotics like gentamicin are being investigated as an alternative to oral antibiotic therapies. This study evaluates the efficacy of the candidate intravesical therapeutic VesiX, a solution containing the cationic detergent Cetylpyridinium chloride, against a broad range of uropathogenic bacterial species clinically isolated from postmenopausal women with recurrent UTI (rUTI). We also evaluate the cytotoxicity of VesiX against cultured bladder epithelial cells and find that low concentrations of 0.0063% and 0.0125% provide significant bactericidal effect toward diverse bacterial species including uropathogenic Escherichia coli (UPEC), Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, and Proteus mirabilis while minimizing cytotoxic effects against cultured 5637 bladder epithelial cells. Lastly, to begin to evaluate the potential utility of using VesiX in combination therapy with existing intravesical therapies for rUTI, we investigate the combined effects of VesiX and the intravesical antibiotic gentamicin. We find that VesiX and gentamicin are not antagonistic and are able to reduce levels of intracellular UPEC in cultured bladder epithelial cells.

IMPORTANCE

When urinary tract infections (UTIs), which affect over 50% of women, become resistant to available antibiotic therapies dangerous complications like kidney infection and lethal sepsis can occur. New therapeutic paradigms are needed to expand our arsenal against these difficult to manage infections. Our study investigates VesiX, a Cetylpyridinium chloride (CPC)-based therapeutic, as a candidate broad-spectrum antimicrobial agent for use in bladder instillation therapy for antibiotic-resistant UTI. CPC is a cationic surfactant that is FDA-approved for use in mouthwashes and is used as a food additive but has not been extensively evaluated as a UTI therapeutic. Our study is the first to investigate its rapid bactericidal kinetics against diverse uropathogenic bacterial species isolated from postmenopausal women with recurrent UTI and host cytotoxicity. We also report that together with the FDA-approved bladder-instillation agent gentamicin, VesiX was able to significantly reduce intracellular populations of uropathogenic bacteria in cultured bladder epithelial cells.

Cetylpyridinium chloride and chlorhexidine show antiviral activity against Influenza A virus and Respiratory Syncytial virus in vitro

BACKGROUND

The oral cavity is the site of entry and replication for many respiratory viruses. Furthermore, it is the source of droplets and aerosols that facilitate viral transmission. It is thought that appropriate oral hygiene that alters viral infectivity might reduce the spread of respiratory viruses and contribute to infection control.

MATERIALS AND METHODS

Here, we analyzed the antiviral activity of cetylpyridinium chloride (CPC), chlorhexidine (CHX), and three commercial CPC and CHX-containing mouthwash preparations against the Influenza A virus and the Respiratory syncytial virus. To do so the aforementioned compounds and preparations were incubated with the Influenza A virus or with the Respiratory syncytial virus. Next, we analyzed the viability of the treated viral particles.

RESULTS

Our results indicate that CPC and CHX decrease the infectivity of both the Influenza A virus and the Respiratory Syncytial virus in vitro between 90 and 99.9% depending on the concentration. Likewise, CPC and CHX-containing mouthwash preparations were up to 99.99% effective in decreasing the viral viability of both the Influenza A virus and the Respiratory syncytial virus in vitro.

CONCLUSION

The use of a mouthwash containing CPC or CHX alone or in combination might represent a cost-effective measure to limit infection and spread of enveloped respiratory viruses infecting the oral cavity, aiding in reducing viral transmission. Our findings may stimulate future clinical studies to evaluate the effects of CPC and CHX in reducing viral respiratory transmissions.

The complex of tannic acid and cetylpyridinium chloride: An antibacterial and stain-removal cleaner for aligners

INTRODUCTION

Effective aligner hygiene is recognized as an important part of orthodontic treatments and oral hygiene. However, there is no effective cleansing method for removable aligners.

METHODS

In this study, we incorporated tannic acid (TA) with cetylpyridinium chloride (CPC) to develop the TA-CPC complex. The antibacterial properties of 15.8 mg/mL TA-CPC against Escherichia coli and Staphylococcus aureus were evaluated in vitro, which were compared with 5.1 mg/mL TA, 10.7 mg/mL CPC, a commercial denture cleansing solution (YA; 15 mg/mL), and water. As for the assessment of stain-removal ability, the aligners stained by coffee were soaked in cleansing solutions, and the color changes (ΔE∗) were calculated on the basis of the CIE L∗a∗b∗ color system, and the National Bureau of Standards system was used for the clinical interpretation of the color change. Atomic force microscope examination, tensile property assessment, and wavelength dispersive x-ray fluorescence analysis were performed to investigate the material compatibility of TA-CPC, and Cell Counting Kit-8 assay and live/dead assay were used to test the cytotoxicity of TA-CPC.

RESULTS

The results showed that TA-CPC had a positive zeta-potential, and cation-π interaction changed the chemical environments of the phenyl group in TA-CPC, resulting in greater inhibition zones of S. aureus and E. coli than other cleaners. The quantification of the biofilm biomass and the fluorescent intensities also reflected that the TA-CPC solution exhibited better antibacterial ability. As for the ability of stain removal, ΔE∗ value of group TA-CPC was 2.84 ± 0.55, whereas those of stained aligners immersed with deionized distilled water, TA, YA, and CPC were 10.26 ± 0.04, 9.54 ± 0.24, 5.93 ± 0.36, and 4.69 ± 0.35, respectively. The visual inspection and National Bureau of Standards ratings also showed that the color of stained aligners cleansed by TA-CPC was much lighter than those of the other groups. Meanwhile, TA-CPC had good compatibility with the aligner material and cells.

CONCLUSIONS

TA-CPC is a promising strategy to inhibit the formation of biofilms and remove the stains on the aligners safely, which may disinfect the aligners to improve oral health and help keep the transparent appearances of aligners without impacting the morphology and mechanical properties.

Antimicrobial and antitumor activities of an alginate-based membrane loaded with bismuth nanoparticles and cetylpyridinium chloride

OBJECTIVE

To evaluate the antitumor and antimicrobial properties of an alginate-based membrane (ABM) loaded with bismuth lipophilic nanoparticles (BisBAL NPs) and cetylpyridinium chloride (CPC) on clinically isolated bacteria and a pancreatic cancer cell line.

MATERIAL AND METHODS

The BisBAL NP-CPC ABM was characterized using optical and scanning electron microscopy (SEM). The antimicrobial potential was measured using the disk-diffusion assay, and antibiofilm activity was determined through the live/dead assay and fluorescence microscopy. The antitumor activity was analyzed on the pancreatic cell line (Panc 03.27) using the MTT assay and live/dead assay with fluorescence microscopy.

RESULTS

After a 24-h exposure (37°C, aerobic conditions), 5 µM BisBAL NP reduced the growth of K. pneumoniae by 77.9%, while 2.5 µM BisBAL NP inhibited the growth of Salmonella, E. faecalis and E. faecium by 82.9%, 82.6%, and 78%, respectively (p < 0.0001). The BisBAL NPs-CPC ABM (at a ratio of 10:1; 500 and 50 µM, respectively) inhibited the growth of all isolated bacteria, producing inhibition halos of 9.5, 11.2, 7, and 10.3 mm for K. pneumoniae, Salmonella, E. faecalis, and E. faecium, respectively, in contrast to the 6.5, 9.5, 8.5, and 9.8 mm obtained with 100 µM ceftriaxone (p < 0.0001). The BisBAL NPs-CPC ABM also reduced bacterial biofilms, with 81.4%, 74.5%, 97.1%, and 79.5% inhibition for K. pneumoniae, E. faecium, E. faecalis, and Salmonella, respectively. Furthermore, the BisBAL NPs-CPC ABM decreased Panc 03.27 cell growth by 76%, compared to 18% for drug-free ABM. GEM-ABM reduced tumoral growth by 73%. The live/dead assay confirmed that BisBAL NPs-CPC-ABM and GEM-ABM were cytotoxic for the turmoral Panc 03.27 cells.

CONCLUSION

An alginate-based membrane loaded with BisBAL NP and CPC exhibits dual antimicrobial and antitumoral efficacy. Therefore, it could be applied in cancer treatment and to diminish the occurrence of surgical site infections.

Mitigating the attachment of Salmonella Infantis on isolated poultry skin with cetylpyridinium chloride

To provide the poultry industry with effective mitigation strategies, the effects of cetylpyridinium chloride (CPC) on the reduction of Salmonella Infantis, hilA expression, and chicken skin microbiota were evaluated. Chicken breast skins (4×4 cm; N = 100, n = 10, k = 5) were inoculated with Salmonella (Typhimurium or Infantis) at 4°C (30min) to obtain 108 CFU/g attachment. Skins were shaken (30s), with remaining bacteria being considered firmly attached. Treatments were applied as 30s dips in 50 mL: no inocula-no-treatment control (NINTC), no treatment control (NTC), tap water (TW), TW+600 ppm PAA (PAA), or TW+0.5% CPC (CPC). Excess fluid was shaken off (30s). Samples were homogenized in nBPW (1 min). Samples were discarded. Salmonella was enumerated and Log10 transformed. Reverse transcriptase-qPCR (rt-qPCR) was performed targeting hilA gene and normalized using the 2-ΔΔCt method. Data were analyzed using one-way ANOVA in RStudio with means separated by Tukey's HSD (P≤0.05). Genomic DNA of rinsates was extracted, 16S rRNA gene (V4) was sequenced (MiSeq), and data analyzed in QIIME2 (P≤0.05 and Q≤0.05). CPC and PAA affected Salmonella levels differently with CPC being effective against S. Infantis compared to TW (P<0.05). Treatment with CPC on S. Infantis-infected skin altered the hilA expression compared to TW (P<0.05). When inoculated with S. Typhimurium, there was no difference between the microbiota diversity of skins treated with PAA and CPC; however, when inoculated with S. Infantis, there was a difference in the Shannon's Entropy and Jaccard Dissimilarity between the two treatments (P<0.05). Using ANCOM at the genus level, Brochothrix was significant (W = 118) among skin inoculated with S. Typhimurium. Among S. Infantis inoculated, Yersiniaceae, Enterobacterales, Lachnospiraceae CHKCI001, Clostridia vadinBB60 group, Leuconostoc, Campylobacter, and bacteria were significant (408). CPC and PAA-treated skins had lowest relative abundance of the genera. In conclusion, CPC mitigated Salmonella Infantis, altered hilA expression, and influenced the chicken skin microbiota.

Maternal exposure to cetylpyridinium chloride impairs oogenesis by causing mitochondria disorder in neonates

Cetylpyridinium Chloride (CPC) is a common disinfectant with potential mitochondrial toxicity. However, the effects of CPC on female reproduction remains unclear. In the present study, pregnant mice were exposed to environmentally relevant doses of CPC for 3 days, the effects were evaluated in the female offspring. Maternal exposure to CPC caused loss of oocytes in neonatal ovaries. TEM analysis of neonatal ovaries showed CPC caused aberrant mitochondrial morphology including vacuolated and disorganized structure, reduced functional cristae. In addition, CPC decreased mitochondrial membrane potential in neonatal oocytes. Seahorse analysis showed that CPC hampered mitochondrial reserve, manifested as reduced spare respiratory capacity. Furthermore, CPC damaged mitochondrial function and impaired developmental competence of MII oocytes, suggesting a persisting impact into adulthood. In summary, this is the first known demonstration that maternal exposure to CPC caused mitochondrial disorders in neonatal ovaries and had long-term effects on fertility of the female offspring.

Pharmaceutical agent cetylpyridinium chloride inhibits immune mast cell function by interfering with calcium mobilization

Cetylpyridinium chloride (CPC) is an antimicrobial used in numerous personal care and janitorial products and food for human consumption at millimolar concentrations. Minimal information exists on the eukaryotic toxicology of CPC. We have investigated the effects of CPC on signal transduction of the immune cell type mast cells. Here, we show that CPC inhibits the mast cell function degranulation with antigen dose-dependence and at non-cytotoxic doses ∼1000-fold lower than concentrations in consumer products. Previously we showed that CPC disrupts phosphatidylinositol 4,5-bisphosphate, a signaling lipid critical for store-operated Ca2+ entry (SOCE), which mediates degranulation. Our results indicate that CPC inhibits antigen-stimulated SOCE: CPC restricts Ca2+ efflux from endoplasmic reticulum, reduces Ca2+ uptake into mitochondria, and dampens Ca2+ flow through plasma membrane channels. While inhibition of Ca2+ channel function can be caused by alteration of plasma membrane potential (PMP) and cytosolic pH, CPC does not affect PMP or pH. Inhibition of SOCE is known to depress microtubule polymerization, and here we show that CPC indeed dose-dependently shuts down formation of microtubule tracks. In vitro data reveal that CPC inhibition of microtubules is not due to direct CPC interference with tubulin. In summary, CPC is a signaling toxicant that targets Ca2+ mobilization.

One-Pot Preparation of Cetylpyridinium Chloride-Containing Nanoparticles for Biofilm Eradication

Quaternary ammonium compounds (QACs) have been widely used due to their excellent antimicrobial activity. However, using the technology where nanomaterials are employed as drug carriers to deliver QAC drugs has not been fully explored. In this study, mesoporous silica nanoparticles (MSNs) with short rod morphology were synthesized in a one-pot reaction using an antiseptic drug cetylpyridinium chloride (CPC). CPC-MSN were characterized via various methods and tested against three bacterial species (Streptococcus mutans, Actinomyces naeslundii, and Enterococcus faecalis), which are associated with oral infections, caries, and endodontic pathology. The nanoparticle delivery system used in this study prolonged the release of CPC. The manufactured CPC-MSN effectively killed the tested bacteria within the biofilm, and their size allowed them to penetrate into dentinal tubules. This CPC-MSN nanoparticle delivery system demonstrates potential for applications in dental materials.

Incorporation of zinc into cetylpyridinium chloride mouthwash affects the composition of multispecies biofilms

This study evaluated the effect of a mouthwash containing 0.075% cetylpyridinium chloride and 0.28% zinc lactate (CPC + Zn) in a multispecies biofilm model. A 7-days 33-species biofilm, formed on Calgary device, was 1-min treated with: 0.12% chlorhexidine (CHX), culture medium (negative control), 0.075% cetylpyridinium chloride (CPC) or CPC + Zn, 2x/day, from day 3 until day 6. The metabolic activity and the microbial composition were evaluated by colorimetric method and checkerboard DNA-DNA hybridization, respectively. The three antimicrobials (CPC, CPC + Zn and CHX) reduced metabolic activity, total biofilm count and several species counts, including Porphyromonas gingivalis, Fusobacterium nucleatum, Parvimonas micra, Campylobacter gracilis and Streptococcus mutans. However, only CPC + Zn reduced counts of the pathogen Prevotella intermedia and did not interfere with the levels of some beneficial species in relation to the negative control. The treatment of multispecies subgingival biofilm with CPC + Zn was effective in controlling periodontal pathogens and favored the colonization of health-associated bacterial species.

Impacts of cetylpyridinium chloride on the behavior and brain neurotransmitter levels of juvenile and adult zebrafish (Danio rerio)

Cetylpyridinium chloride (CPC) is a cationic surfactant that has been widely used as an antibacterial ingredient in pharmaceutical and personal care products. Due to its high residue in surface waters, there is increasing concern over the potential risk of CPC to aquatic ecosystems. However, knowledge of its impacts on fish is still limited. Therefore, this study exposed juvenile and adult zebrafish to CPC (0, 10, and 40 μg/L) for four days. Subsequently, changes in their behavioral traits and brain levels of several neurotransmitters were investigated. The behavioral assay showed that CPC exposure significantly decreased the locomotor activity and social interaction of zebrafish at both life stages, and juveniles were more sensitive to CPC exposure than adults. In the control groups, the brain neurotransmitters concentrations increased with age in zebrafish. However, CPC exposure tended to increase the brain neurotransmitter levels of juveniles but decreased their levels in adults. Correlation analysis revealed that the brain monoamine neurotransmitters and their turnover might play important roles in the life stage-dependent behavioral response to CPC. In particular, the DOPAC/DA ratio was significantly associated with CPC-induced hypoactivity and reduced social interactions in juveniles but not adults. Our findings demonstrated that CPC exposure could cause abnormal behavior in juvenile and adult zebrafish and disturb their brain neurotransmitters, even at environmentally relevant concentrations, and thus highlighted the necessity for further assessing its potential risks to aquatic ecosystems.

Cetylpyridinium chloride (CPC) reduces zebrafish mortality from influenza infection: Super-resolution microscopy reveals CPC interference with multiple protein interactions with phosphatidylinositol 4,5-bisphosphate in immune function

The COVID-19 pandemic raises significance for a potential influenza therapeutic compound, cetylpyridinium chloride (CPC), which has been extensively used in personal care products as a positively-charged quaternary ammonium antibacterial agent. CPC is currently in clinical trials to assess its effects on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) morbidity. Two published studies have provided mouse and human data indicating that CPC may alleviate influenza infection, and here we show that CPC (0.1 μM, 1 h) reduces zebrafish mortality and viral load following influenza infection. However, CPC mechanisms of action upon viral-host cell interaction are currently unknown. We have utilized super-resolution fluorescence photoactivation localization microscopy to probe the mode of CPC action. Reduction in density of influenza viral protein hemagglutinin (HA) clusters is known to reduce influenza infectivity: here, we show that CPC (at non-cytotoxic doses, 5-10 μM) reduces HA density and number of HA molecules per cluster within the plasma membrane of NIH-3T3 mouse fibroblasts. HA is known to colocalize with the negatively-charged mammalian lipid phosphatidylinositol 4,5-bisphosphate (PIP2); here, we show that nanoscale co-localization of HA with the PIP2-binding Pleckstrin homology (PH) reporter in the plasma membrane is diminished by CPC. CPC also dramatically displaces the PIP2-binding protein myristoylated alanine-rich C-kinase substrate (MARCKS) from the plasma membrane of rat RBL-2H3 mast cells; this disruption of PIP2 is correlated with inhibition of mast cell degranulation. Together, these findings offer a PIP2-focused mechanism underlying CPC disruption of influenza and suggest potential pharmacological use of this drug as an influenza therapeutic to reduce global deaths from viral disease.

Commonly used surfactants sodium dodecyl sulphate, cetylpyridinium chloride and sodium laureth sulphate and their effects on antioxidant defence system and oxidative stress indices in Cyprinus carpio L.: an integrated in silico and in vivo approach

The present study evaluated the homology modelling, in silico prediction and characterization of Cyprinus carpio cytochrome P450, as well as molecular docking experiments between the modelled protein and the surfactants sodium dodecyl sulphate (SDS), sodium laureth sulphate (SLES) and cetylpyridinium chloride (CPC). Homology modelling of cytochrome P450 was performed using the best fit template structure. The structure was optimized with 3D refine, and the ultimate 3D structure was checked with PROCHEK and ERRATA. ExPASy's ProtParam was likewise used to analyse the modelled protein's physiochemical and stereochemical attributes. To establish the binding pattern of each ligand to the targeted protein and its effect on the overall protein conformation, molecular docking calculations and protein-ligand interactions were performed. Our in silico analysis revealed that hydrophobic interactions with the active site amino acid residues of cytochrome p450 were more prevalent than hydrogen bonds and salt bridges. The in vivo analysis exhibited that exposure of fish to sublethal concentrations (10% and 30% of 96 h LC₅₀) of SDS (0.34 and 1.02 mg/l), CPC (0.002 and 0.006 mg/l) and SLES (0.69 and 2.07 mg/l) at 15d, 30d and 45d adversely affected the oxidative stress and antioxidant enzymes (CAT, SOD, GST, GPx and MDA) in the liver of Cyprinus carpio. As a result, the study suggests that elicited oxidative stress, prompted by the induction of antioxidant enzymes activity, could be attributable to the stable binding of cytochrome P450 with SDS, CPC and SLES which ultimately leads to the evolution of antioxidant enzymes for its neutralization.

Novel composite cement containing the anti-microbial compound CPC-Montmorillonite

OBJECTIVES

The aim of this study was to evaluate the mechanical properties, bonding performance and anti-microbial activity of a novel composite cement containing cetylpyridinium chloride (CPC) modified montmorillonite ('CPC-Mont'), and using these parameters to determine the optimal particle size and concentration of CPC-Mont the composite cement can be loaded with.

METHODS

CPC-Mont particles with a median diameter of 30 and 7 µm were prepared and added to a composite cement at a concentration of 2, 3, 4, 5 and 7.5 wt%. Mechanical properties and bonding performance of the experimental composite cements were evaluated by 3-point bending and micro-tensile bond-strength testing. The amount of CPC released from the cement disks was quantified using a UV-vis recording spectrophotometer. The anti-biofilm activity was studied using scanning electron microscopy (SEM).

RESULTS

Adding 30-μm CPC-Mont decreased the mechanical properties and bonding performance of the composite cement, while no reduction was observed for the 7-μm CPC-Mont loaded cement formulation. Although CPC release substantially decreased during the 7-day period assessed, 5- and 7.5-wt% CPC-Mont loaded composite cement inhibited biofilm formation for 30 days.

SIGNIFICANCE

Loading composite cement with CPC-Mont with a median diameter of 7 µm at concentrations of 5-7.5 wt% was effective in achieving continuous anti-biofilm activity, while maintaining mechanical strength and bonding performance.

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

Oxidative stress in benthic oligochaete worm, Tubifex tubifex induced by sublethal exposure to a cationic surfactant cetylpyridinium chloride and an anionic surfactant sodium dodecyl sulfate

The present study was assessed to determine the in vivo toxic effects of a cationic surfactant, cetylpyridinium chloride (CPC), and an anionic surfactant, sodium dodecyl sulfate (SDS) in terms of oxidative stress biomarkers in benthic oligochaete worm Tubifex tubifex for 14 days. The investigation demonstrated that sublethal concentrations of CPC (0.0213, and 0.0639 mg L^-1) and SDS (1.094 and 3.092 mg L^-1)induced paramount alterations in the oxidative stress enzymes in Tubifex tubifex. Superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH), and glutathione peroxidase (GPx) exhibited an initial notable increase in their activities in the surfactants exposed worms at 1d and 7d of exposure period followed by consequential reduction at 14d exposure period with respect to control, while catalase (CAT) and malondialdehyde (MDA) activities markedly incremented gradually throughout the exposure periods. Through the construction of the correlation matrix and integrated biomarker response (IBR), the effects of CPC and SDS on Tubifex tubifex were distinguished. These results indicate that exposure to these cationic and anionic surfactants modulates the levels of oxidative stress enzymes in Tubifex tubifex.

Antimicrobial Activity, Biocompatibility and Anti-inflammatory Properties of Cetylpyridinium Chloride-based Mouthwash Containing Sodium Fluoride and Xylitol: An In Vitro Study

PURPOSE

The use of a mouthwash as an adjunct to mechanical plaque removal may be useful to improve oral hygiene. In this study, cetylpyridinium chloride (CPC)-based mouthwashes containing sodium fluoride and xylitol (X-PUR Opti-Rinse 0.05% NaF and X-PUR Opti-Rinse 0.2% NaF) were evaluated for their antimicrobial activity against important oral pathogens associated with dental caries, periodontal disease, and candidiasis. Moreover, their biocompatibility and anti-inflammatory properties were assessed.
Materials and Methods: Antimicrobial activity was determined using a disk-diffusion assay, a microplate dilution assay, and the European standard protocols for antiseptics. Microbicidal properties were assessed against both planktonic and biofilm cultures. An oral epithelial cell model was used to evaluate the biocompatibility of mouthwashes and their ability to attenuate cytokine secretion.
Results: Using three different antimicrobial assays, the CPC-based mouthwashes were found to be highly active against the tested microorganisms. More specifically, the mouthwashes met the European Standard NF EN 1040 and NF EN 1275 defined as a log10 reduction ≥ 5 (≥ 99.999% killing) for bacteria and log10 reduction ≥ 4 (≥ 99.99% killing) for fungi, respectively. The CPC-based mouthwashes were also bactericidal against biofilms of S. mutans, S. sobrinus, and P. gingivalis. Using an oral epithelial cell model, the CPC-based mouthwashes were found to be less cytotoxic than a chlorhexidine-containing mouthwash used as control. Lastly, the CPC-based mouthwashes decreased the secretion of interleukin-6 and interleukin-8 by lipopolysaccharide-stimulated oral epithelial cells.
Conclusion: The CPC-based mouthwashes supplemented with sodium fluoride (0.05% or 0.2%) and xylitol (10%) were highly active against important oral pathogens. Moreover, using an oral epithelial cell model, these mouthwashes were found to be biocompatible and to exhibit anti-inflammatory activity.

Antimicrobial effects of viscous mouthrinses containing cetylpyridinium chloride and isopropyl methylphenol

PURPOSE

To evaluate the in vitro antimicrobial effect of low- and high-viscosity experimental mouthrinses containing cetylpyridinium chloride (CPC) and 4-isopropyl-3-methylphenol (IPMP) on Streptococcus pneumoniae, Klebsiella pneumoniae, Porphyromonas gingivalis, Streptococcus mutans, and Candida albicans.

METHODS

Low- and high-viscosity experimental mouthrinses containing 0.05% CPC and 0.1% IPMP were fabricated. Non-viscous mouthrinses containing either CPC- or IPMP were used as controls. The antimicrobial activity (sterilization or exposure time) of mouthrinses was evaluated based on the bactericidal criterion of <10¹ viable cells in 0.1 mL of culture medium.

RESULTS

The sterilization time of the low-viscosity experimental mouthrinse was shorter than that of the high-viscosity mouthrinse. However, whereas a 10-minute exposure to the low-viscosity mouthrinse resulted in no viable cells of C. albicans, neither the CPC- or IPMP mouthrinses had an antimicrobial effect for the same exposure time. These findings show that the low-viscosity experimental mouthrinse containing anodal CPC and neutral IPMP exhibited superior antimicrobial effects against pneumonia- and oral infection-related bacteria compared with the control mouthrinses.

CLINICAL SIGNIFICANCE

In Japan, the oral care with the low-viscosity experimental mouthrinse containing CPC and IPMP as alternatives to those based on chlorhexidine are available for preventing the development of pneumonia- and oral infection-related bacteria.

Inhibition of Staphylococcus aureus and Pseudomonas aeruginosa biofilms by quatsomes in low concentrations

Staphylococcus aureus and Pseudomonas aeruginosa are primary pathogens in chronic rhinosinusitis (CRS), and the presence of S. aureus and P. aeruginosa biofilms has been associated with negative outcomes after surgery. This study investigated the inhibition effect of cetylpyridinium chloride (CPC)-quatsomes at low concentrations on both S. aureus and P. aeruginosa biofilms in vitro , as well as their toxicities towards cultured human airway epithelial (NuLi-1) cells. S. aureus ATCC 25923 and P. aeruginosa ATCC 15692 were used to establish biofilms. CPC-quatsome and CPC micelle solutions at concentrations of 0.01%, 0.025%, and 0.05% were prepared. AlamarBlue was used to test the viability of both planktonic S. aureus and P. aeruginosa and their biofilms after treatment for 5 min and 2 h, respectively. Confocal laser scanning microscopy (CLSM) was used to investigate the interactions between CPC-quatsomes and S. aureus and P. aeruginosa biofilms. A lactate dehydrogenase (LDH) assay was used to determine the toxicity of CPC-quatsomes on NuLi-1 cells. CPC-quatsome and CPC micelle solutions had significant inhibition effects at all tested concentrations on planktonic S. aureus and P. aeruginosa and their biofilms after 5-min exposure (P  <  0.05). In the CLSM study, different interactions between CPC-quatsomes and S. aureus or P. aeruginosa biofilms were observed. After 2-h treatment, the size of S. aureus biofilms decreased, while the number of dead bacteria increased in P. aeruginosa biofilms. Neither CPC-quatsomes nor CPC micelle solutions showed significant toxicity on NuLi-1 cell at all tested CPC concentrations (P  <  0.05). CPC-quatsomes at low concentrations inhibited S. aureus and P. aeruginosa in both planktonic form and biofilms. No adverse effects on NuLi-1 cells were observed, indicating their promising potential in the treatment of CRS.

Synthesis, thermal and surface activity of cationic single chain metal hybrid surfactants and their interaction with microbes and proteins

A series of water-soluble metal functionalized surfactants have been prepared using commercially available surfactant cetyl pyridinium chloride and transition metal salts. These complexes were characterized in the solid state by elemental analysis, FTIR, 1H NMR and thermogravimetric analysis. The interfacial surface activity and aggregation behaviour of the metallosurfactants were analysed through conductivity, surface tension and small angle neutron scattering measurements. Our results show that the presence of metal ions as co-ions along with counter ions favours micellization at a low critical micellization concentration (CMC). Small angle neutron scattering revealed that the metallomicelles are of a prolate ellipsoidal shape and exhibit strong counterion binding. This article further describes the interaction of the metallosurfactants with transport protein Bovine Serum Albumin (BSA) using different spectroscopic techniques. A spectroscopic study was used to study the binding, interaction and quenching mechanism of BSA with the metallosurfactants. Gel electrophoresis (SDS-PAGE) and circular dichroism (CD) investigated the structural and conformational changes produced in BSA due to the metallosurfactants. The results indicate that there is an alteration in the secondary structure of BSA due to the electrostatic interaction between positive head groups and metal co-ions of the metallosurfactants and negatively charged amino acids of BSA. As the concentration increases, the α-helicity of BSA decreases and all the three studied metallosurfactants gave comparable results. Finally, the in vitro cytotoxicity and antimicrobial activity of the metallosurfactants were evaluated against erythrocytes and microorganisms, which showed prominent effects related to the presence of a metal ion in metallomicelles of the hybrid surfactants.

Penetration and bactericidal efficacy of two oral care products in an oral biofilm model

PURPOSE

To investigate the immediate penetration and bactericidal effect of two oral care products marketed in China on an intact natural plaque biofilm model at different time points.

METHODS

Eight subjects (aged 20 to 30 years; Turesky Plaque Index Score 2 to 3) were enrolled in the study according to the inclusion criteria. Plaque accumulators were worn by the subjects for 6 and 48 hours for harvesting the dental biofilm. Then the biofilms from different groups were stained with the LIVE/DEAD BacLight fluorescence system to investigate the changes in thickness and fluorescence intensity of living bacteria in biofilm 5 and 15 minutes post-treatment with a mouthrinse containing 0.074% cetylpyridinium chloride (1-minute treatment) or a toothpaste supernatant containing 1.16% stannous chloride (2-minute treatment). In addition, a specific Sn2+ probe was utilized to evaluate the penetration of Sn2+ in the biofilm. Fluorescent images were collected using confocal laser scanning microscopy. Analysis of covariance was used for statistical analyses. All comparisons were two-sided using a 5% level of significance.

RESULTS

The thickness of generated plaque biofilm increased gradually from 7.352±4.22 µm at 6 hours to 16.73±7.38 µm at 48 hours (P< 0.05), whereas the thickness and fluorescence intensity of living bacteria stayed unchanged over time. After the treatment of toothpaste supernatant, the ratios of living bacteria thickness and fluorescence intensity of 6- and 48-hour plaque biofilm were significantly decreased (P< 0.05). Treatment of mouthrinse reduced the ratio of living bacteria thickness, but showed no significant impact on overall fluorescence intensity of living bacteria. For 48-hour biofilm, toothpaste supernatant significantly reduced fluorescence intensity of living bacteria from outer layer through inner layer, whereas the mouthrinse showed bactericidal effect only in the outer layer and middle layer. A wide distribution of Sn2+ was shown in the biofilm with the treatment of the tested toothpaste.

CLINICAL SIGNIFICANCE

This biofilm model proved to be useful and appropriate for pre-clinical testing of anti-plaque agents. A brief exposure of the biofilm to the tested toothpaste produced significant losses in bacteria viability across outer-middle-inner layers. The tested mouthrinse exerted its bactericidal effect mostly in outer and middle layers of biofilm. The penetration of Sn2+ in the biofilm performed an important function in the bactericidal effect of the toothpaste.

Impact of modification with cetylpyridinium chloride - a potential cariogenic microbiota inhibitor, on selected physical-mechanical properties of the water-activated glass-ionomer

PURPOSE

Teeth caries is one of predominant civilization diseases. Dental fillings with antimicrobial addition might allow prevention of secondary caries. The purpose of this study was to evaluate hardness and tensile strength of cetylpyridinium chloride modified water activated glass-ionomer cement.

METHODS

Samples with diameter of 6 mm and height of 3 mm made of water-activated glass-ionomer cement were control group (0.0%). Test groups were series of samples of the same dimensions, with addition of cetylpyridinium chloride antimicrobial in concentrations of 0.5, 1.0, 1.5 and 2.0%. Two subgroups were prepared in each group to determine Vickers Hardness and Diametral Tensile Strength after 1 and 24 hours of sample storage in distilled water.

RESULTS

During hardness studies, no strong effect of antimicrobial concentration on hardness of samples was observed. Higher hardness values after 24 hours were demonstrated for all groups, compared to the samples tested after 1 hour. The exception was the group with the addition of 1% cetylpyridinium chloride, in which no statistically significant differences were observed. Diametral Tensile Strength values for samples tested after 1 hour decreased with increasing antibacterial concentration. A similar relationship was noticed for samples tested after 24 hours. No statistically signifi- cant differences were found between test samples after 1 or 24 hours.

CONCLUSIONS

There was no significant effect of cetylpyridinium chloride concentration on the hardness of the samples that significantly increased during the study. With the increase in antimicrobial concentration a decrease in diametral tensile strength value was observed, but these values did not change over time.

The antibacterial activity and release of quaternary ammonium compounds in an orthodontic primer

The aim of this study was to evaluate the impact of 10 wt% benzalkonium chloride (TB-BAC) or 10 wt% cetylpyridinium chloride (TB-CPC) on the antimicrobial properties of the orthodontic adhesive primer, Transbond XTT (TB). Antimicrobial activity was assessed using a zone of inhibition diffusion test and the release of the antimicrobial compounds was monitored by high performance liquid chromatography (HPLC). Shear bond strength (SBS) was tested using bovine enamel. Control, TB, specimens failed to demonstrate intrinsic antibacterial activity at 1, 7 and 14 days; whereas, TB-BAC and TB-CPC showed antibacterial effects at all times. HPLC analysis indicated no significant differences in the release behaviour of TB-BAC and TB-CPC (t-test, p > 0.05), except for the 7-day release which was higher for TB-BAC (p < 0.05). By 14 days the extents of release were 27 ± 2% and 25 ± 5% of the total initial loading for TB-BAC and TB-CPC, respectively. The incorporation of 10 wt% BAC or CPC in Transbond XTT adhesive primer also resulted in superior shear bond strength at 7 and 14 days (Fisher s LSD, p < 0.05) with no significant change in the mode ofbracket failure under shear stress (Pearson's chi-squared, p > 0.05).

Inhibition of malodorous gas formation by oral bacteria with cetylpyridinium and zinc chloride

OBJECTIVE

The antimicrobial efficacy of zinc- (ZnCl₂) and cetylpyridinium-chloride (CPC) and their inhibition capacity on volatile sulfur compound (VSC) production by oral bacterial strains were investigated.

DESIGN

Minimum inhibitory concentrations (MIC) and growth curves were determined for ZnCl₂, CPC, and CPC with ZnCl₂ solutions against eight oral microorganisms (Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, Tannerella forsythia, Staphylococcus aureus and Streptococcus mutans) known to be involved in the pathophysiology of both halitosis and periodontal disease. Gas chromatography was applied to measure VSCs (H₂S, CH₃SH, (CH₃)₂S) production levels of each strains following exposure to the solutions.

RESULTS

ZnCl₂ and CPC effectively inhibited growth of all eight strains. ZnCl₂ was generally more effective than CPC in suppressing bacterial growth excluding A. actinomycetemcomitans, P. intermedia, and T. forsythia. Synergism between CPC and ZnCl₂ was shown in A. actinomycetemcomitans. The MIC for CPC was significantly lower than ZnCl₂. VSC production was detected in five bacterial strains (A. actinomycetemcomitans, F. nucleatum, P. gingivalis, T. denticola, and T. forsythia). Each bacterial strain showed unique VSCs production profiles. H₂S was produced by F. nucleatum, P. gingivalis, and T. denticola, CH₃SH by all five strains and (CH₃)₂S by A. actinomycetemcomitans, F. nucleatum, P. gingivalis, and T. denticola. Production of CH₃SH, the most malodorous component among the three major VSCs from mouth air was evident in F. nucleatum and T. forsythia.

CONCLUSION

Both ZnCl₂ and CPC effectively inhibit bacterial growth causative of halitosis and periodontal disease, resulting in a direct decrease of bacterial VSCs production.

Lipopolysaccharide and lipoteichoic acid binding by antimicrobials used in oral care formulations

PURPOSE

To study the reactivity of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) with the cationically charged agents cetylpyridinium chloride, stannous fluoride, and the non-cationic agent triclosan. We also assessed the effect of these agents to inhibit LPS and LTA binding to cellular Toll-like Receptors (TLRs) in vitro.

METHODS

The ability of these antimicrobials to bind with LPS and/or LTA was assessed in both the Limulus amebocyte lysate and BODIPY-TR-cadaverine dye assays. Mass spectroscopy was then used to confirm that stannous fluoride directly binds with LPS and to determine stoichiometry. Lastly, we looked for possible inhibitory effects of these antimicrobial agents on the ability of fluorescently conjugated LPS to bind to TLR4 expressed on HEK 293 cells.

RESULTS

Cetylpyridinium chloride (CPC) and stannous salts including stannous fluoride interfered with LPS and LTA reactivity in both dye assays, while triclosan had no effect. Mass spectroscopy revealed direct binding of stannous fluoride with E. Coli LPS at 1:1 stoichiometric ratios. In the cellular assay, cetylpyridinium chloride and stannous fluoride, but not triclosan, inhibited LPS binding to TLR4.

CLINICAL SIGNIFICANCE

These results support a potential mechanism of action for stannous fluoride and CPC formulated in oral products in which these ingredients bind bacterial toxins and potentially render them less toxic to the host. These results may influence home care recommendations for patients at risk for plaque-related diseases.

Effects of Remineralization Agents on Artificial Carious Lesions

PURPOSE

The purpose of this study was to evaluate the remineralization potentials of different agents on demineralized enamel surfaces.

METHODS

Four hundred and sixty extracted human molars with artificial carious lesions were divided into six groups: (1) control; (2) acidulated phosphate fluoride (APF); (3) Curodont Repair (CR); (4) silver diamine fluoride (SDF); (5) ammonium hexafluorosilicate (SiF); and (6) SiF plus cetylpiridinium chloride (SiF+CPC). They were subdivided according to immersion periods (seven out of 30 days). After demineralization and remineralization procedures, microhardness test (VHN), energy-dispersive X-ray spectroscopy analysis, and confocal laser scanning microscopy evaluation were performed. The data were statistically analyzed.

RESULTS

By the 30-day remineralization, the mean differences in VHN values were ranked as follows, in order: (1) CR; (2) APF; (3) SiF; (4) SiF+CPC; (5) SDF; and (6) control (P<0.05). The calcium (Ca) content and calcium/phosphate ratio for all groups were significantly higher after 30 days (P<0.05). The greatest lesion depth changes were observed in the CR, APF, SiF, and SDF groups (P<0.05), while the greatest fluorescence changes were observed in the APF, SiF, and CR groups (P<0.05).

CONCLUSIONS

The remineralization was most successful in the CR, APF, and SiF groups, with higher values than for those of the other treatments.

Antibacterial effects of conventional glass ionomer cement

OBJECTIVES

The antibacterial activity of conventional glass ionomer cement against three different microorganism strains alone and following incorporation of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride was evaluated.

METHODS

Agar diffusion method was used to determine the inhibitory effect of the conventional glass ionomer cement ChemFlex on Streptococcus mutans, Lactobacillus casei and Actinomyces viscosus. Bacterial strains were inoculated into BHIB, and incubated in an anaerobic atmosphere (37 °C). From the bacteria grown in the liquid medium, the density of the inoculum was set to be equivalent to McFarland 2 standard. In Shaedler agar, 350 μL of the bacterial suspension were equally spread. Specimens (4 mm × 6 mm) were prepared from the cement without and with addition of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride. The inhibition zones were determined after 48 hours, after 2, 7 and 21 days of incubation.

RESULTS

The combination ChemFlex + Benzalkonium Chloride has the best effect on the three analysed bacteria. The Benzalkonium Chloride antibacterial compound has a stronger antibacterial effect than Cetylpyridinium Chloride.

CONCLUSIONS

Glass ionomer cements can potentially be used as a medium for slow release of active antimicrobial components, and they have the potential to improve clinical outcomes of the cements (Tab. 3, Fig. 3, Ref. 31).

Nanoemulsion Therapy for Burn Wounds Is Effective as a Topical Antimicrobial Against Gram-Negative and Gram-Positive Bacteria

The aim of this study is to investigate the antimicrobial efficacy of two different nanoemulsion (NE) formulations against Gram-positive and Gram-negative bacteria in an in vivo rodent scald burn model. Male Sprague-Dawley rats were anesthetized and received a partial-thickness scald burn. Eight hours after burn injury, the wound was inoculated with 1 × 10(8) colony-forming units of Pseudomonas aeruginosa or Staphylococcus aureus. Treatment groups consisted of two different NE formulations (NB-201 and NB-402), NE vehicle, or saline. Topical application of the treatment was performed at 16 and 24 hours after burn injury. Animals were killed 32 hours after burn injury, and skin samples were obtained for quantitative wound culture and determination of dermal inflammation markers. In a separate set of experiments, burn wound progression was measured histologically after 72 hours of treatment. Both NE formulations (NB-201 and NB-402) significantly reduced burn wound infections with either P. aeruginosa or S. aureus and decreased median bacterial counts at least three logs when compared with animals with saline applications (p < .0001). NB-201 and NB-402 also decreased dermal neutrophil recruitment and sequestration into the wound as measured by myeloperoxidase (MPO) assay and histopathology (p < .05). In addition, there was a decrease in the proinflammatory dermal cytokines (interleukin 1-beta [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]) and the neutrophil chemoattractants CXCL1 and CXCL2. Using histologic examination, it was found that both NB-201 and NB-402 appeared to suppress burn wound progression 72 hours after injury. Topically applied NB-201 and NB-402 are effective in decreasing Gram-positive and Gram-negative bacteria growth in burn wounds, reducing inflammation, and abrogating burn wound progression.

Antimicrobial effectiveness of cetylpyridinium chloride and zinc chloride-containing mouthrinses on bacteria of halitosis and peri-implant disease

PURPOSE

To clarify the antimicrobial efficacy of zinc chloride (ZnCl2) and cetylpyridinium chloride (CPC) by testing their impact on the growth of seven bacterial strains known to be involved in the pathophysiology of both peri-implant disease and halitosis-Staphylococcus aureus, Streptococcus mutans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Treponema denticola, and Tannerella forsythia.

MATERIALS AND METHODS

A time-response growth curve was obtained. Commercial mouthrinses with CPC, ZnCl2, or both were added to the media in a final concentration of 0.25% CPC, 2.5% ZnCl2, and 2.5% ZnCl2 with 0.25% CPC.

RESULTS

Both CPC and ZnCl2 effectively inhibited the growth of almost all bacterial strains tested except T denticola. ZnCl2 was generally more effective in suppressing bacterial growth than CPC. ZnCl2 with CPC showed the greatest inhibitory activities on almost all strains of bacterial growth except for P gingivalis and T denticola, followed by ZnCl2, then CPC, thus suggesting the possibility of a synergistic effect of the two agents. P gingivalis exhibited a different pattern because ZnCl2 showed the most significant inhibitory effect. CPC did not show growth inhibitory effects on T denticola, but ZnCl2 did.

CONCLUSION

Zinc and CPC effectively inhibit bacterial growth that causes both halitosis and peri-implant disease. The effect is even more powerful when applied in combination.

Antibacterial efficacy of a cetylpyridinium chloride-based mouthrinse against Fusobacterium nucleatum and in vitro plaques

PURPOSE

To assess the antimicrobial effects of a fluoride-free and alcohol-free mouthrinse containing 0.075% CPC (test rinse, TR) compared with an otherwise-identical CPC-free control rinse (CR).

METHODS

Activity against laboratory cultures of Fusobacterium nucleatum, a bacterium associated with gingival disease, was determined using viable counting following 30-second exposures to TR and CR. Effects against intact saliva-derived plaque biofilms were quantified using confocal microscopy coupled with three-dimensional image analyses (viability profiling).

RESULTS

Short exposures to TR caused significant inactivation of F. nucleatum, as determined by viable counting (c. 3 log reduction compared to the control rinse, P < 0.05). Confocal microscopy revealed extensive inactivation of complex oral biofilms following treatment with TR; biofilms were significantly less viable than those exposed to CR and three-dimensional images revealed extensive zones of dead bacteria even within plaque depths. In conclusion, this investigation demonstrates that the CPC-containing mouthrinse has significant antibacterial efficacy against oral bacteria associated with gingival disease and significantly inactivated plaque biofilm in comparison to a relevant control.

Mouthwashes: Rationale for use

PURPOSE

To update the rationale for the use of mouthwashes and summarize data on the incorporation of an antibacterial, cetylpyridinium chloride (CPC), into a new mouthwash formulation. Data from various published articles are reviewed which demonstrate the value of mouthwashes. Also this Special Issue provides research supporting the efficacy of 0.075% cetylpyridinium chloride in a new, alcohol-free mouthwash formulation (Colgate Total).

RESULTS

Benefits of mouthwashes include improving the reduction of plaque biofilm as an adjunct to oral hygiene, killing bacteria in areas difficult to reach by normal oral hygiene, killing bacteria on non-tooth oral surfaces, reaching bacteria subgingivally by placement in an irrigator, and supporting a positive effect on oral health by reducing bacteremia from oral micro-organisms. The benefits of including CPC in this new formulation are demonstrated by in vitro and clinical studies which demonstrate the efficacy of this formulation of CPC on biofilm as well as an effect on the reduction of plaque and gingivitis in three clinical studies.

Gingival health benefits of essential oil, 0.075% cetylpyridinium chloride and control mouthrinses: A 4-week randomized clinical study

PURPOSE

This randomized, single center, examiner-blind, controlled, parallel-group, 4-week clinical study compared the antiplaque/anti-gingivitis efficacy of an essential oil (EO) containing mouthrinse versus a 0.075% cetylpyridinium chloride (CPC) containing mouthrinse. A 5% hydroalcohol solution was included as a control group.

METHODS

165 systemically healthy volunteers (18-72 years of age), with mild to moderate plaque-related gingivitis were enrolled in this clinical trial; 162 subjects completed the study. At baseline and 4-week visits, subjects received an oral examination, gingivitis (MGI), gingival bleeding (BI) and plaque (PI) assessments. Following randomization, subjects began rinsing with 20 mL of the assigned mouthrinse for 30 seconds, in conjunction with their usual oral hygiene, twice daily for the duration of the study.

RESULTS

All rinses were well tolerated by the subjects. EO was statistically significantly superior to CPC with a reduction in mean MGI of 5.9%, and in mean PI of 6.4%. Statistically significant reductions in gingivitis, bleeding and plaque were observed for both EO and CPC when compared to the negative control; mean MGI and mean PI were reduced by 13.0% and 18.9% for EO and by 7.6% and 13.3% for CPC. EO also statistically significantly reduced the proportion of gingival bleeding sites compared to CPC by 7.6% (P = 0.012) and compared to control by 10.6% (P < 0.001). For the post hoc sitewise analyses, at 4 weeks, the mean percentage of healthy sites for EO, CPC and Control were 7.4%, 1.1% and 0.8%, respectively and the mean percentage of virtually plaque free sites for EO, CPC and control were 5.4%, 3.8% and 0.4% respectively. The mean percentages of more inflamed gingival sites for EO, CPC and control were 20.4%, 26.2% and 45.7%, respectively. The mean percentage of tooth surfaces with heavier accumulations of plaque (PI scores ≥ 3) was 50.9% for EO, 56.1% for CPC and 81.1% for control. Reduction of gingival inflammation and dental plaque was statistically significantly superior for EO compared to both 0.075% CPC and negative control. Both marketed antimicrobial mouthrinses showed a beneficial result in gingival health and in reducing plaque accumulation as early as 4 weeks.

Interference of Antimicrobial Activity of Combinations of Oral Antiseptics Against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus

PURPOSE

The purpose of this study was to compare the effects of combinations of sodium fluoride and antiseptic compounds on the growth of Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus.

METHODS

The agar diffusion assay was used to determine bacterial growth inhibition.

RESULTS

Of the combinations tested, 0.1 percent sodium fluoride and five percent povidone iodine produced synergistic antibacterial effects against S. mutans and S. sanguinis. The combination of 10 percent povidone iodine and 0.5 percent sodium hypochlorite produced additive antibacterial effects against L. acidophilus. Interference was seen in some combinations such as 0.01 percent chlorhexidine and 0.25 percent sodium lauryl sulphate, 0.5 percent sodium hypochlorite and 10 percent povidone iodine, and 0.01 percent cetyl pyridium chloride and 0.1 percent sodium fluoride. However, 0.1 percent sodium fluoride combined with 0.01 percent chlorhexidine did not interfere with the antibacterial effects of chlorhexidine against S. mutans or S. sanguinis.

CONCLUSIONS

Combinations of common antiseptics and fluoride compounds can produce interference, synergistic, or additive effects. The combination of 0.1 percent sodium fluoride and five percent povidone iodine had the greatest potential for suppression of S. mutans.

In vitro comparison of commercial oral rinses on bacterial adhesion and their detachment from biofilm formed on hydroxyapatite disks

PURPOSE

This in vitro study was designed to assess the effectiveness of three oral rinses on bacterial adherence to epithelial cells and hydroxyapatite surfaces. The role of oral rinses on the detachment of bacteria from biofilm was also evaluated.

MATERIALS AND METHODS

The efficacy of three oral rinses, Acclean, Noplak and Prevention were tested against a wide range of oral bacteria. Oral rinse antimicrobial activity was determined by an MTT assay for bacterial viability, by live/ dead staining and by measuring the bacterial metabolic activity using an XTT assay.

RESULTS

The two oral rinses that contained 0.12% chlorhexidine had the greatest antibacterial activity on both planktonic and bio lm-grown organisms when compared to the Prevention oral rinse.

CONCLUSION

Both Acclean and Noplak were extremely effective in lowering the number of bacteria attached to buccal epithelial cells and pelllicles. In addition, these two oral rinses were also effective against the biofilm bacteria.

Development of sustained antimicrobial-release systems using poly(2-hydroxyethyl methacrylate)/trimethylolpropane trimethacrylate hydrogels

Reconstructive materials with sustained antimicrobial effects could be useful for preventing infectious diseases in an environment containing indigenous bacteria or fungi such as the oral cavity. With the objective of applying a non-biodegradable hydrogel to resin-based materials as a reservoir for water-soluble antimicrobials, novel hydrogels consisting of 2-hydroxyethyl methacrylate (HEMA) and trimethylolpropane trimethacrylate (TMPT) were fabricated. Cetylpyridinium chloride (CPC) was loaded into five hydrogels comprising different ratios of HEMA/TMPT, and their ability to release as well as to be recharged with CPC was examined in vitro. A polyHEMA/TMPT hydrogel comprising 50% HEMA/50% TMPT could be effectively loaded and recharged with CPC by immersion into a CPC solution, demonstrating the longest release of CPC, above the concentration required to inhibit bacteria and fungi. The binding of CPC to the hydrogels was mainly through hydrophobic interaction. Loading of CPC into a hydrogel by mixing CPC powder with the HEMA/TMPT monomer before polymerization resulted in marked extension of the initial CPC-release period. The CPC-pre-mixed hydrogel was confirmed to exhibit antibacterial activity by agar diffusion tests. It is possible to achieve a sustained release system for antimicrobials by pre-mix loading and recharging CPC into a 50% HEMA/50% TMPT hydrogel.

Comparative bioavailability and antimicrobial activity of cetylpyridinium chloride mouthrinses in vitro and in vivo

PURPOSE

Commercialized cetylpyridinium chloride (CPC) mouthrinses were compared for antimicrobial substantivity/bioavailability in an in vitro disk retention assay (DRA) and clinical antimicrobial activity in vivo in the plaque glycolysis and regrowth method (PGRM).

METHODS

Formulations compared in this testing included commercially available CPC mouthrinses: Crest Pro Health (CPH), (containing 700 ppm formulated CPC); Colgate Total Puerto Rico (CT450), (containing 450 ppm formulated CPC); Colgate Total US (CT750), (containing 750 ppm formulated CPC); and Scope Mouthwash (SCP), (containing 450 ppm formulated CPC). A water control (CTR) was included in one of the PGRM clinical trials. Two separate clinical PGRM studies employed a controlled, double-blind, randomized, crossover design where qualified adult PGRM panelists were supplied with acclimation NaF dentifrice for use throughout the trials. On treatment days, subjects sampled baseline plaque and then rinsed with assigned mouthrinse following morning toothbrushing. Treated plaque samples were collected 15 and 45 minutes after rinsing. Sampled plaques were vortexed, normalized for biomass and incubated under standard conditions to assess glycolysis. pH response of treated plaques in incubation buffers were compared to baseline untreated plaque values and an Area Under Curve (AUC) composite/aggregate analysis of glycolysis inhibition was used for treatment comparisons. A laboratory disk retention substantivity/bioavailability assay measured adsorption affinity of CPC in mouthrinse for anionic cellulose disks in vitro.

RESULTS

Clinical PGRM studies showed significant differences in antibacterial clinical efficacy of commercialized mouthrinses. Combining clinical study results reveals rank ordered efficacy CPH > CT750 > SCP > CT450 > CTR. Comparison of DRA to PGRM glycolysis showed a linear relation highlighting correlation of CPC bioavailability to clinical antimicrobial performance of CPC mouthrinses.

Interactions between non-phospholipid liposomes containing cetylpyridinium chloride and biofilms of Streptococcus mutans: modulation of the adhesion and of the biodistribution

Cetylpyridinium chloride (CPC) is a surfactant that binds strongly to bacteria and bacterial biofilms. In this study, fluorescence-based techniques were used to determine the penetration and adhesion of CPC when it was introduced in liposomes. In spite of a reduced adhesion as compared to pure CPC micelles, CPC-containing liposomes adhered significantly to the biofilms of Streptococcus mutans. In contrast, no binding was observed for liposomes that were composed of phosphatidylcholine-cholesterol. The influence of the charge of the liposome on its adhesion to biofilms was studied using cholesterol (Chol) and cholesterol sulfate (Schol). In spite of similar binding to the biofilms, positively charged CPC/Chol liposomes were located mainly in the core of the biofilm microcolonies, whereas the negatively charged CPC/Schol liposomes were mainly concentrated at their periphery. This effect may be attributed to the different availability of the CPC head group. In summary, this work demonstrates the high potential for tailoring drug nanovectors by modulating sterol selection in order to selectively target and bind biofilms.

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.

Biological evaluation of quaternary bis ammonium salt and cetylpyridinum bromide against S. epidermidis biofilm

Quaternary ammonium compounds are broad-spectrum bacteriocides widely used as antiseptics, disinfection and preservation agents. The aim of this study was to examine the activity of two quaternary ammonium salts, cetylpyridinum bromide and a newly synthesized quaternary bis ammonium salt, against S. epidermidis biofilm. The average values of killing efficiency for cetylpyridinum bromide ranged from 26.6% to 64.1% for all tested concentrations (0.125 to 8.0 microg x mL(-1)) and for quaternary bis ammonium salt the percentage of killing efficiency ranged from 59.7% to 88.4% for tested concentrations (from 2.0 to 128.0 microg x mL(-1)). Both tested compounds significantly affect staphylococcal biofilms, but any of used concentrations caused a total eradication of bacterial biofilm.

Fate of sputum samples transported in bottles containing cetylpyridinium chloride and sodium chloride: a national reference laboratory study

The transportation of sputum samples may sometimes take more than one week which results in an increased contamination rate and loss of positive cultures. The current study was planned to analyze the recovery rate of mycobacteria from transported samples with and without Cetylpyridinium chloride (CPC). Addition of CPC is useful for isolation of M. tuberculosis from sputum subjected to long-term storage.

Antibacterial activity of ammonium hexafluorosilicate solution with antimicrobial agents for the prevention of dentin caries

PURPOSE

This study evaluated the antibacterial activity of the SiF solution with the addition of antibacterial agents on a Streptococcus mutans biofilm.

METHODS

Various antibacterial SiF solutions were prepared by adding chlorhexidine, cetylpyridinium chloride, isopropyl methylphenol, or epigallocatechin gallate. Hydroxyapatite pellets treated with several SiF solutions were immersed in BHI inoculated with S. mutans standardized suspension. The number of S. mutans cells adhered to each pellet was evaluated.

RESULTS

SiF with the addition of CPC was the most effective for reducing the adherence of bacteria and inhibiting the formation ofbiofilm, showing the same level as AgF, In contrast, the addition of other antibacterial agents to SiF reduced the original antibacterial activity of SiF solution.

Microbiological effects of an antiseptic mouthrinse in irradiated cancer patients

OBJECTIVE

To assess the microbiological effects of an antiseptic, non-alcohol based mouth-rinse containing chlorhexidine and cetylpyridinium chloride, in patients undergoing radiation therapy for head-and-neck cancer.

STUDY DESIGN

This was a parallel, double-blind, prospective, randomized clinical trial, including patients irradiated as part of the therapy of head-and-neck cancer, aged 18-75, with at least 10 teeth, and willing to sign an informed consent. Cancer patients were randomly assigned to one of the two treatments (test mouth-rinse or a placebo). Three visits were scheduled (baseline, 14 and 28 days). Microbiological findings were evaluated in tongue, mucosa and subgingival samples, by means of culture. Microbiological variables were assessed by means of the Mann-Whitney, Wilcoxon and chi-square tests.

RESULTS

70 patients were screened and 36 were included. The detection of Candida species in mucosa and tongue samples showed significant reductions in the test group. Total bacterial counts decreased in both groups from baseline to the 2-week visit, while minor changes occurred between 2 and 4 weeks (effects on P. gingivalis, P. intermedia, C. rectus, E. corrodens).

CONCLUSIONS

Within the limitations of the small sample size, this study suggests that the use of the tested mouth-rinse may lead to improvements in microbiological parameters in patients irradiated for head-and-neck cancer.

Disinfection of toothbrushes contaminated with Streptococcus mutans

PURPOSE

To determine the most effective method to kill Streptococcus mutans on contaminated toothbrushes.

METHODS

Seven toothbrushes (one for each treatment and the control) were contaminated with S. mutans. Toothbrushes were then rinsed in phosphate buffered saline (PBS) and treated as follows: (1) control without treatment; (2) air dry for 4 hours; (3) Crest Pro-Health mouthwash for 20 minutes; (4) Listerine mouthwash for 20 minutes; (5) normal cleaning cycle in a dishwasher; (6) microwave on high power for 5 minutes; and (7) ultraviolet light using the DenTek Toothbrush Sanitizer for 10 minutes. All toothbrushes were rinsed again with PBS. The bristles were cut and vortexed in PBS. Serial dilutions were performed and the number of colonies enumerated after incubation. The experiment was independently repeated seven times.

RESULTS

The Crest Pro-Health mouthwash and the dishwasher almost completely eliminated S. mutans. The second most effective treatment was the microwave. The Listerine mouthwash and the air dry groups were not significantly different from each other and ranked third. Although UV light significantly decreased the number of bacteria compared to the control, reduction in the number of S. mutans CFU was significantly lower than that of all the other treatments evaluated. Crest Pro-Health mouthwash for 20 minutes and a normal dishwasher cycle are the most effective methods to eradicate S. mutans from contaminated toothbrushes. Dent

Occlusion of dentin tubules with antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries

PURPOSE

To evaluate the degree of penetration of an ammonium hexafluorosilicate [SiF: (NH4)2SiF6] solution containing various antibacterial agents into dentin and the depth of dentin tubule occlusion by the precipitate.

METHODS

Various antibacterial SiF solutions were prepared with the addition to chlorhexidine (CHX), cetylpyridinium chloride (CPC), isopropyl methylphenol (IPMP), or epigallocatechin gallate (EGCG), respectively. Two types of dentin disks were prepared from extracted teeth. One was a dentin surface covered with a smear layer, and the other treated with EDTA for 2 minutes to remove the smear layer and open dentin tubules. Then, the disks were treated with SiF solution with or without antibacterial agents for 3 minutes. The dentin surface and a longitudinally divided surface were observed with scanning electron microscopy (SEM) immediately after SiF treatment and after immersion in synthetic saliva for 7 days.

RESULTS

SEM photographs demonstrated that dentin tubules after treatment with SiF were occluded homogeneously and similar to those on conventional SiF treatment regardless of the addition of an antibacterial agent. However, the depth of occlusion became significantly shallower when SiF was applied to dentin specimens covered with a smear layer.

Antimicrobial activity of nanoemulsion on cariogenic Streptococcus mutans

OBJECTIVE

To assess antimicrobial activities of nanoemulsion (NE) to control the adhesion and biofilm formation by Streptococcus mutans by in vitro.

DESIGN

In vitro antimicrobial susceptibility of nanoemulsion was determined as per National Committee for Clinical Laboratory Standards guidelines and agar diffusion, serial dilution technique for the determination of minimum inhibitory concentration and minimum bactericidal concentration (MIC/MBC). Efficacy was tested by kinetics of killing, biofilm assay and scanning electron microscopy.

RESULTS

: NE concentrations ranging from 1:100 to 1:10,000 dilutions were effective against S. mutans as shown through MIC/MBC assays. NE showed antimicrobial activity against planktonic cells at high dilutions, confirmed by time kill studies. 4-day-old S. mutans biofilms were treated with NE; subsequent reductions of bacterial cell counts were noticed with decreasing dilutions. Staining of NE-treated biofilms with LIVE/DEAD BacLight resulted in dead cell areas of up to 48% in 1 min, 84% at 1h and significant (<0.05) increases in dead cell counts at all time points. Damage to cell membranes and cell walls of S. mutans by NE was demonstrated using scanning electron microscopy (SEM).

CONCLUSION

These results suggest that nanoemulsion has effective antibacterial activity against S. mutans and may be a useful medication in the prevention of dental caries.

Haemolytic action of N-alkylpolymethylenediamines

The haemolytic action of various N-alkyl derivatives (lauryl; C12H25-, myristyl; C14H29-, palmityl; C16H33-) of 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane was examined using rabbit red blood cells. The activities of the various derivatives were compared with those of antiplaque agents commonly used as mouthwashes; cetylpyridinium chloride (CP) and chlorhexidine acetate (CH). The haemolytic activities of these agents were dependent on the length of the N-alkyl chain, whereas the number of methylene groups between the nitrogen atoms had little effect. The order of potency was CP, N-palmityl derivatives, N-myristyl derivatives &gt; N-lauryl derivatives &gt; CH which was similar to the order of the antiplaque effect evaluated in-vitro.

An in vitro comparative study determining bactericidal activity of stabilized chlorine dioxide and other oral rinses

OBJECTIVE

The study was conducted to determine the bactericidal activity of a stabilized chlorine dioxide oral rinse (ClōSYS Oral Rinse) compared to products currently available on the market.

METHODS

Oral bacteria associated with gingivitis and periodontitis were exposed to rinses for one minute and five minutes. The numbers of colony forming units per milliliter (CFU/ml) were measured prior to and following exposure to determine the bactericidal activity.

RESULTS

As expected, Listerine and Crest Pro-Health demonstrated complete kill on all bacteria exposed within one minute. Breath Rx exhibited the weakest levels of bactericidal effects overall. ClōSYS and chlorhexidine rinses proved identical 100% kills against the periodontal pathogens at five minutes; in some cases, ClōSYS oral rinse achieved a higher kill at the one-minute mark over the chlorhexidine rinse.

CONCLUSION

The results demonstrated that ClōSYS Oral Rinse has potential for providing a therapeutic benefit, making it an attractive option to induce compliance in patients concerned about taste and tooth discoloration during oral health therapy.

In vitro antibacterial efficacy of cetylpyridinium chloride-containing mouthwashes

OBJECTIVE

The objective of this study was to examine the ability of three CPC-containing mouthwashes to kill planktonic bacteria in an in vitro short-exposure assay.

METHODS

This blind study was conducted on two common oral bacterial species: Aggregatibacter (Actinobacillus) actinomycetemcomitans and Streptococcus mutans. The following mouthwashes were tested: two containing 0.075% CPC and 0.05% NaF in an alcohol-free base, and one containing 0.075% CPC and 0.05% NaF plus 6% alcohol. Additionally, a 0.05% NaF-only mouthwash was included as a negative control. Bacteria were exposed to one of the test mouthwashes for 30 seconds and then washed thoroughly, serially diluted, and plated on appropriate media to determine viable bacterial counts. Viable counts were converted to a log reduction in colony forming units (CFUs) relative to the negative control.

RESULTS

All three test mouthwashes included in this study gave a statistically significant reduction of > 3 log CFUs relative to samples treated with the negative control.

CONCLUSION

All three experimental 0.075% CPC mouthwash formulas gave a > 99.9% reduction in viable bacteria of both species following 30 seconds of treatment.

Efficacy of an alcohol-free CPC-containing mouthwash against oral multispecies biofilms

OBJECTIVE

The aim of this work was to develop two static-model multispecies oral biofilm systems to compare the efficacy of a placebo mouthwash to an alcohol-free mouthwash containing 0.075% CPC.

METHODS

Two model biofilm systems were used: a 24-well glass-bottom microplate (GM) system and a chamber slide (CS) system. These were inoculated with Schaedler media containing pooled, unfiltered saliva. During incubation at 37 degrees C in 5% CO2, Schaedler media was replaced every 24 hours. Five-day and 10-day multispecies biofilms in the GM and CS systems were then exposed to phosphate buffered saline, the placebo mouthwash, or the alcohol-free 0.075% CPC-containing mouthwash. Biofilms were visualized in three-dimensions by Confocal Laser Scanning Microscopy (CLSM), and fluorometric analyses were performed on biofilms in the GM system.

RESULTS

CLSM demonstrated that regardless of the model system used, the alcohol-free 0.075% CPC-containing mouthwash solution increased the number of damaged biofilm cells. The efficacy of CPC was inversely related to the age of the biofilm. A contrariety between the two biofilm systems was that the CS system indicated that alcohol-free 0.075% CPC-containing mouthwash partially disrupted biofilms. Fluorometric analysis ofGM biofilms also demonstrated that the alcohol-free 0.075% CPC-containing mouthwash damaged biofilm cells.

CONCLUSION

Two static oral multispecies model biofilms systems demonstrated that an alcohol-free 0.075% CPC-containing mouthwash had greater antimicrobial efficacy than a placebo mouthwash. The alcohol-free 0.075% CPC-containing formulation is effective against multispecies oral biofilms.