Chlorhexidine: is it still the gold standard?

Dose-response effect of chlorhexidine on a multispecies oral biofilm formed on pure titanium and on a titanium-zirconium alloy

This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.

Evaluation of wound healing and postoperative pain after oral mucosa laser biopsy with the aid of compound with chlorhexidine and sodium hyaluronate: a randomized double blind clinical trial

OBJECTIVES

The aim of this study is to evaluate secondary intention healing process and postoperative pain of oral soft tissues after laser surgery with the use of a compound containing chlorhexidine and sodium hyaluronate.

MATERIALS AND METHODS

This double-blind, randomized clinical study included 56 patients affected by benign oral lesions and subjected to excisional biopsy with diode laser and randomly divided into three groups. Study group (SG) received 0.2% chlorhexidine digluconate and 0.2% sodium hyaluronate treatment; control group (CG) received 0.2% chlorhexidine digluconate; and placebo group (PG) followed the same protocol, taking a neutral solution having the same organoleptic characteristics. Wound healing was evaluated using percentage healing index (PHI). Numeric rating scale (NRS) was used to evaluate postoperative pain.

RESULTS

PHI (T1 = 7 days) was 67.25% for SG, 58.67% for CG, and 54.55% for PG. PHI (T2 = 14 days) was 94.35% for SG, 77.79% for CG, and 78.98% for PG. A statistically significant difference was between the groups for PHI at T2 p = 0.001. No difference was detectable for pain index.

CONCLUSIONS

A solution containing sodium hyaluronate and chlorhexidine is a good support to increase wound healing by secondary intention after laser biopsy, but no differences were in postoperative perception of pain.

CLINICAL RELEVANCE

The use of the tested solution can be recommended after laser oral biopsies, to achieve a healing without suture. About the postoperative pain, the compound has not showed the same results and did not have measurable effects.

Comparative evaluation of efficacy of Murraya koenigii and chlorhexidine gluconate in the treatment of gingivitis: A randomized controlled clinical trial

Background

Herbal products are widely substituting synthetic antimicrobials due to their minimal adverse effects and cost-effectiveness. Murraya koenigii (curry leaf) is an easily available green leafy vegetable, which is known for their antimicrobial, antioxidative, and cytotoxic activity. However, no published literature available evaluates their effectiveness in treating gingival inflammation. This study was aimed to evaluate the effectiveness of M. koenigii mouthwash in reduction of plaque and gingivitis in comparison with commercially available chlorhexidine (CHX) mouthwash.

Materials and Methods

This single-center, parallel-arm, randomized controlled clinical trial was carried out among individuals reported to the institution. A total of 45 participants with mild-to-moderate gingivitis were selected and divided into three groups. Group A and B participants undergone scaling and were instructed to use M. koenigii and CHX mouthwashes, respectively. Group C participants have received only scaling. All the participants were recalled after 14 days of prescribed mouthwash use and clinical parameters were recorded. One-way analysis of variance test and Student's paired t-test were used for inter- and intra-group comparison of parameters, respectively.

Results

On intragroup comparison of clinical parameters, all the three groups showed a statistically significant difference with P ≤ 0.05. On pairwise comparison, it showed a significant difference for Group B versus Group C and Group A versus Group C, while between Group A and Group B showed no significant difference.

Conclusion

M. koenigii mouthwash is equally effective as CHX, in treating plaque-induced gingivitis.

Antimicrobial efficacy of alternative compounds for use in oral care toward biofilms from caries-associated bacteria in vitro

For caries‐active patients, antimicrobial measures may be useful in addition to mechanical biofilm removal. The aim of this study was to investigate the antimicrobial efficacy of alternative compounds for use in oral care from two main categories (i.e., preservatives and natural compounds) toward biofilms from caries‐associated bacteria as compared to oral care gold‐standards chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC), and zinc. Compounds were screened in initial Streptococcus mutans biofilms. Then, the most effective compounds were further investigated in mature S. mutans and polymicrobial biofilms comprising Actinomyces naeslundii, Actinomyces odontolyticus, and S. mutans. Here, distinct treatment periods and concentrations were evaluated. Biofilms were visualized by scanning electron microscopy and bacterial membrane damage was evaluated by means of flow cytometry and staining with SYBR Green and propidium iodide. Citrus extract was the only compound exhibiting similar antimicrobial efficacy in initial S. mutans biofilms (>5 log₁₀) as compared to CHX and CPC, but its effect was clearly inferior in mature S. mutans and polymicrobial biofilms. Flow cytometric data suggested that the mechanism of antimicrobial action of citrus extract may be based on damage of bacterial membranes similar to CHX and CPC. From all alternative compounds investigated in this study, citrus extract exhibited the highest antimicrobial efficacy toward in vitro biofilms from caries‐associated bacteria, but still was less effective than oral care gold‐standard antiseptics CHX and CPC. Nevertheless, citrus extract may be a valuable antimicrobial compound for use in oral care for caries‐active patients.

Caries lesion remineralization with fluoride toothpastes and chlorhexidine - effects of application timing and toothpaste surfactant

Habitual toothbrushing with fluoridated toothpaste followed by rinsing with antibacterial mouthwashes is a method to maintain good oral hygiene and to diminish the occurrence and severity of dental caries and periodontal disease. However, our understanding of how antimicrobial agents in mouthwashes affect fluoride-mediated caries lesion remineralization is still poor.

Antimicrobial and cytotoxic effects of denture base acrylic resin impregnated with cleaning agents after long-term immersion

The coadjutant method for denture cleansing most used by denture wearers is immersion in chemical agents, which are toxic when in direct contact with cells. However, clinically, the contact between these chemical agents and prosthetic tissues does not occur directly, but rather with what remained impregnated into acrylic bases, even after rinsing the disinfected dentures. This study evaluated the antimicrobial and cytotoxic effects of a denture acrylic resin after successive cycles of daily overnight immersion in 1% sodium hypochlorite (1%NaClO) and 2% chlorhexidine digluconate (2%CHX), simulating the periods of 9 months or 1.5 year. Microbiological and cytotoxic assays were performed, respectively, by broth microdilution method (Candida albicans or Staphylococcus aureus) and MTT assay. Chemical residues of 2%CHX impregnated into the denture acrylic resin had an antimicrobial effect on both immersion periods, which was not observed with those of 1%NaClO. However, residues of 2%CHX were severely cytotoxic to human gingival fibroblasts compared to those of 1%NaClO and acrylic resin (not submitted to the denture cleansers), which were slightly cytotoxic. Even at low concentrations recommended for overnight soaking of removable dentures, the chemical residues of CHX may result in some degree of toxicity to the denture-bearing mucosa after long-term daily immersion.

Evaluation of substantivity of hypochlorous acid as an antiplaque agent: A randomized controlled trial

BACKGROUND

Hypochlorous acid (HOCl) is a non-antibiotic antimicrobial substance with significant effects on pathogenic oral micro-organisms. The effects of HOCl as an antiplaque agent have not been studied.

OBJECTIVE

The aim of this study was to evaluate the substantivity of HOCl mouthwashes compared with chlorhexidine (CHX) rinses and a placebo.

MATERIALS AND METHODS

A double-blind randomized controlled trial with 75 participants was conducted. Participants were divided into five groups using block randomization: 0.025% HOCl, 0.05% HOCl, 0.12% CHX, 0.2% CHX, and sterile water as a placebo. Participants were instructed to use each rinse solution for 30 seconds after dental prophylaxis. Samples of saliva were taken at baseline and after 30 seconds, 1, 3, 5 and 7 hours to assess substantivity, and bacterial viability was established by the fluorescence method. Visible plaque in all participants was assessed with the Turesky index at baseline and at 7 hours, and adverse events were also assessed.

RESULTS

HOCl led to a 33% reduction in bacterial counts in the saliva after 30 seconds compared with a 58% reduction by CHX. HOCl has no substantivity, and bacterial counts returned to baseline after 1 hour. Placebo treatment led to the highest plaque count after 7 hours compared with the CHX and HOCl groups, although the differences were not significant. HOCl rinsing induced the highest percentages of unpleasant taste and dryness sensations.

CONCLUSIONS

HOCl rinses have an initial effect on bacterial viability in saliva but have no substantivity. Other mechanisms may explain its antiplaque effect.

The effect of chlorhexidine on dental calculus formation: an in vitro study

Background

Chlorhexidine gluconate (CHG) has been proven to be effective in preventing and controlling biofilm formation. At the same time, an increase in calculus formation is known as one of considerable side effects. The purpose of this study was to investigate whether mineral deposition preceding a calculus formation would occur at an early stage after the use of CHG using an in vitro saliva-related biofilm model.

Methods

Biofilms were developed on the MBEC™ device in brain heart infusion (BHI) broth containing 0.5% sucrose at 37 °C for 3 days under anaerobic conditions. Biofilms were periodically exposed to 1 min applications of 0.12% CHG every 12 h and incubated for up to 2 days in BHI containing a calcifying solution. Calcium and phosphate in the biofilm were measured using atomic absorption spectrophotometry and a phosphate assay kit, respectively. Morphological structure was observed using a scanning electron microscope (SEM), and chemical composition was analyzed with an electron probe microanalyzer (EPMA).

Results

The concentrations of Ca and Pi following a single exposure to CHG increased significantly compared with the control. Repeatedly exposing biofilms to CHG dose-dependently increased Ca deposition, and the amount of Ca was five times as much as that of the control. Pi levels in CHG-treated biofilms were significantly higher than those from the control group (p < 0.05); however, the influence of the number of exposures was limited. Analyses using an SEM and EPMA showed many clusters containing calcium and phosphate complexes in CHG-treated biofilms. Upon composition analysis of the clusters, calcium was detected at a greater concentration than phosphate.

Conclusions

Findings suggested that CHG may promote mineral uptake into the biofilm soon after its use. It is necessary to disrupt the biofilm prior to the start of a CHG mouthwash in order to reduce the side effects associated with this procedure. The management of patients is also important.

Effectiveness of three mouthwashes - Manuka honey, Raw honey, and Chlorhexidine on plaque and gingival scores of 12-15-year-old school children: A randomized controlled field trial

Objectives:

The aim of this study is to compare the effectiveness of three types of mouthwashes manuka honey (MH), raw honey (RH), and chlorhexidine (CHX) on plaque and gingival scores of 12–15-year-old government school children.

Study Design:

This study was a double-blind, randomized controlled field trial conducted in Belagavi city, India.

Materials and Methods:

One hundred and thirty-five government school children aged 12–15 years were randomly selected and allocated into three groups, RH, MH, and CHX mouthwash groups. Ten milliliters each of honey-based mouthwash formulation and CHX mouthwashes (0.2%) were administered according to the group allocation twice daily for 21 days. All the children were examined at baseline, 22^nd day (after discontinuation of mouthwash) and 28^th day (1 week after discontinuation of mouthwash) for Gingival (Loe and silness 1963) and Plaque Index (Silness and Loe, 1964).

Results:

Descriptive statistics was applied for distribution of study participants according to age and gender. One-way ANOVA followed by Tukey's post hoc test and repeated measures ANOVA test followed by Bonferroni's post hoc were applied for inter- and intragroup comparison, respectively. Statistically significant reductions (P < 0.001) in plaque and gingival scores were observed in all the three types of mouthwash groups at the end of the 22^nd day and 28^th day. MH and RH mouthwash demonstrated equal effectiveness, whereas CHX mouthwash showed the maximum reduction in clinical parameters.

Conclusion:

Honey-based mouthwash showed a promising antimicrobial effect on dental caries and plaque and gingival scores.

Synergistic mechanism of Ag+-Zn2+ in anti-bacterial activity against Enterococcus faecalis and its application against dentin infection

Background

Ag⁺ and Zn²⁺ have already been used in combinations to obtain both enhanced antibacterial effect and low cytotoxicity. Despite this, it is still unclear how the Zn²⁺ co-works with Ag⁺ in the synergistic antibacterial activity. The main purposes of this study were to investigate the co-work pattern and optimum ratio between Ag⁺ and Zn²⁺ in their synergistic antibacterial activity against E. faecalis, the possible mechanisms behind this synergy and the primary application of optimum Ag⁺–Zn²⁺ co-work pattern against the E. faecalis biofilm on dentin. A serial of Ag⁺–Zn²⁺ atomic combination ratios were tested on both planktonic and biofilm-resident E. faecalis on dentin, their antibacterial efficiency was calculated and optimum ratio determined. And the cytotoxicity of various Ag⁺–Zn²⁺ atomic ratios was tested on MC3T3-E1 Cells. The role of Zn²⁺ in Ag⁺–Zn²⁺co-work was evaluated using a Zn²⁺ pretreatment study and membrane potential—permeability measurement.

Results

The results showed that the synergistically promoted antibacterial effect of Ag⁺–Zn²⁺ combinations was Zn²⁺ amount-dependent with the 1:9 and 1:12 Ag⁺–Zn²⁺ atomic ratios showing the most powerful ability against both planktonic and biofilm-resident E. faecalis. This co-work could likely be attributed to the depolarization of E. faecalis cell membrane by the addition of Zn²⁺. The cytotoxicity of the Ag⁺–Zn²⁺ atomic ratios of 1:9 and 1:12 was much lower than 2% chlorhexidine.

Conclusions

The Ag⁺–Zn²⁺ atomic ratios of 1:9 and 1:12 demonstrated similar strong ability against E. faecalis biofilm on dentin but much lower cytotoxicity than 2% chlorhexidine. New medications containing optimum Ag⁺–Zn²⁺ atomic ratios higher than 1:6, such as 1:9 or 1:12, could be developed against E. faecalis infection in root canals of teeth or any other parts of human body.

Antibacterial Activity of Nitric Oxide-Releasing Hyperbranched Polyamidoamines

Hyperbranched polyamidoamines (h-PAMAM) were prepared using a one-pot reaction to have similar molecular weight to third generation PAMAM (G3-PAMAM) dendrimers, and then functionalized with N-diazeniumdiolate nitric oxide (NO) donors. A wide range of NO storage capacities (∼1-2.50 μmol mg-1) and NO-release kinetics (t1/2 ∼30-80 min) were achieved by changing the extent of propylene oxide (PO) modification. The therapeutic potential of these materials was evaluated by studying their antibacterial activities and toxicity against common dental pathogens and human gingival fibroblast cells, respectively. Our results indicate that the combination of NO release and PO modification is necessary to yield h-PAMAM materials with efficient bactericidal action without eliciting unwarranted cytotoxicity. Of importance, NO-releasing PO-modified h-PAMAM polymers exhibited comparable biological properties (i.e., antibacterial action and cytotoxicity) to defect-free G3-PAMAM dendrimers, but at a substantially lower synthetic burden.

Comparative evaluation of the efficacy of a herbal mouthwash and chlorhexidine mouthwash on select periodontal pathogens: An in vitro and ex vivo study

Background:

Several herbal mouthwash and herbal extracts have been tested in vitro and in vivo in search of a suitable adjunct to mechanical therapy for long-term use. In this study, we aimed to look at the antimicrobial effect of the herbal mouthwash and chlorhexidine (CHX) mouthwash on select organisms in in vitro test and an ex vivo model.

Materials and Methods:

The antimicrobial effects were determined against standard strains of bacteria that are involved in different stages of periodontal diseases. The in vitro tests included determination of minimum inhibitory concentration (MIC) using broth dilution and agar diffusion. In the ex vivo part of the study supragingival dental plaque were obtained from 20 periodontally healthy adult volunteers. Descriptive analysis was done for the entire quantitative and qualitative variable recorded.

Results:

The MIC by broth dilution method found no statistically significant difference between the mouthwashes. The agar dilution method showed CHX was more effective as compared to the herbal mouthwash against standard strains of Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans. However, no difference was observed between the mouthwashes for Porphyromonas, Pseudomonas aeruginosa, and Fusobacterium nucleatum. The ex vivo results conclude that none of the selected mouthwashes were statistically significantly different from each other.

Conclusion:

In the present study, CHX showed higher levels of antimicrobial action than the herbal mouthwash against bacterial species. The results reinforce the earlier findings that the in vitro testing is sensitive to methods and due diligence is needed when extrapolating the data for further use. However, long-term use and in vivo effectiveness against the periopathogens need to be tested in well-planned clinical trials.

Controlling Streptococcus mutans and Staphylococcus aureus biofilms with direct current and chlorhexidine

Microbial biofilms formed on biomaterials are major causes of chronic infections. Among them, Gram-positive bacteria Streptococcus mutans and Staphylococcus aureus are important pathogens causing infections associated with dental caries (tooth-decay) and other medical implants. Unfortunately, current antimicrobial approaches are ineffective in disrupting established biofilms and new methods are needed to improve the efficacy. In this study, we report that the biofilm cells of S. mutans and S. aureus can be effectively killed by low-level direct current (DC) and through synergy in concurrent treatment with DC and chlorhexidine (CHX) at low concentrations. For example, after treatment with 28 µA/cm² DC and 50 µg/mL CHX for 1 h, the viability of biofilm cells was reduced by approximately 4 and 5 logs for S. mutans and S. aureus, respectively. These results are useful for developing more effective approaches to control pathogenic biofilms.

Optimization of Adhesive Pastes for Dental Caries Prevention

Dental caries prevention products available on the market contain only remineralizing agents or antibacterial agents. This study aimed to develop adhesive pastes containing calcium phosphate and α-mangostin for dental caries prevention using the optimization technique. Calcium phosphate was used as a remineralizing agent, and extracted α-mangostin was used as an antibacterial agent. The effect of the independent variables, which were fumed silica, Eudragit^® EPO, polyethylene glycol, and ethyl alcohol, on the responses was investigated. The drying time, erosion rate, calcium release rate, and α-mangostin release rate were established as the measured responses. An equation and a model of the relationship were constructed. An optimal formulation was obtained, and its effect on dental caries prevention was investigated using the pH-cycling model. The quadratic equation revealed that the drying time, calcium release rate, and α-mangostin release rate tended to decrease when increasing the fumed silica and decreasing other factors. The erosion rate tended to increase when decreasing Eudragit^® EPO and increasing other factors. The observed responses of the optimal adhesive pastes were not significantly different from the predicted responses. This result demonstrated that optimization is an efficient technique in the formulation development of the adhesive pastes. In addition, the optimal adhesive pastes could enhance acid resistance activity to the tooth enamel.

In vitro studies of the antimicrobial effect of non-thermal plasma-activated water as a novel mouthwash

The aim of this study was to evaluate the antimicrobial effects of non-thermal plasma-activated water (PAW) as a novel mouthwash in vitro. Three representative oral pathogens - Streptococcus mutans, Actinomyces viscosus and Porphyromonas gingivalis - were treated with PAW. The inactivation effect was evaluated using the colony-forming unit (CFU) method, and the morphological and structural changes of a cell were observed by scanning electron microscopy and transmission electron microscopy (TEM). The physicochemical properties of PAW were analysed, and its influence on the leakage of intracellular proteins and DNA was evaluated. The results showed significant reduction of Streptococcus mutans within 60 s, of Actinomyces viscosus within 40 s, and of Porphyromonas gingivalis in less than 40 s. Scanning electron microscopy and TEM images showed that the normal cell morphology changed by varying degrees after treatment with PAW. Intracellular proteins (280 nm) and DNA (260 nm) leaked from all three species of bacteria after treatment with PAW. Reactive oxygen species (ROS), especially atomic oxygen (O), hydroxyl radical (˙OH), and hydrogen peroxide (H₂ O₂ ), were generated and led to strong oxidative stress and cell damage. These results suggest that PAW has potential use as a novel antimicrobial mouthwash.

Application of xanthan gum as polysaccharide in tissue engineering: A review

Xanthan gum is a microbial high molecular weight exo-polysaccharide produced by Xanthomonas bacteria (a Gram-negative bacteria genus that exhibits several different species) and it has widely been used as an additive in various industrial and biomedical applications such as food and food packaging, cosmetics, water-based paints, toiletries, petroleum, oil-recovery, construction and building materials, and drug delivery. Recently, it has shown great potential in issue engineering applications and a variety of modification methods have been employed to modify xanthan gum as polysaccharide for this purpose. However, xanthan gum-based biomaterials need further modification for several targeted applications due to some disadvantages (e.g., processing and mechanical performance of xanthan gum), where modified xanthan gum will be well suited for tissue engineering products. In this review, the current scenario of the use of xanthan gum for various tissue engineering applications, including its origin, structure, properties, modification, and processing for the preparation of the hydrogels and/or the scaffolds is precisely reviewed.

In vitro chlorhexidine release from alginate based microbeads for periodontal therapy

Periodontitis is one of the most common infectious diseases globally that, if untreated, leads to destruction of the tooth supporting tissues and finally results in tooth loss. Evidence shows that standard procedures as mechanical root cleaning could be supported by further treatment options such as locally applied substances. Due to gingival crevicular fluid flow, substances are commonly washed out off the periodontal pockets. The evaluation of administration techniques and the development of local drug releasing devices is thus an important aspect in periodontal research. This study describes the development and examination of a new alginate based, biodegradable and easily applicable drug delivery system for chlorhexidine (CHX). Different micro beads were produced and loaded with CHX and the release profiles were investigated by high performance liquid chromatography (HPLC). The in vitro-demonstrated release of CHX from alginate based beads shows comparable releasing characteristics as clinically approved systems. Yet many characteristics of this new delivery system show to be favourable for periodontal therapy. Easy application by injection, low production costs and multifunctional adaptions to patient related specifics may improve the usage in routine care.

Effects of polyhexamethylene guanidine phosphate on human gingival fibroblasts

OBJECTIVE

Polyhexamethylene guanidine phosphate (PHMG-P) was compared to chlorhexidine (CHX) in order to determine potential cytotoxic and immune-modulatory effects on human gingival fibroblasts.

MATERIALS AND METHODS

Cytotoxic effects of PHMG-P and CHX on human gingival fibroblasts were assessed using cell viability assay at various time points and concentrations. The effects of PHMG-P and CHX on the secretion of prostaglandin (PG) E₂, interleukin (IL)-6, IL-8 and matrix metalloproteinase (MMP)-1 by non-stimulated or IL-1β stimulated fibroblasts were evaluated by enzyme-linked immunosorbent assays.

RESULTS

PHMG-P concentration 0.00009% led to the total loss of fibroblast viability within 24 h, whereas inhibition of fibroblast viability by CHX occurred at significantly higher concentrations of 0.0009% (p < .001). Short-term exposure to 0.005% PHMG-P led to loss of fibroblast viability after 5 min, whilst cells exposed to 0.005% CHX survived 30 min of treatment (p < .001). IL-1β stimulation induced an inflammatory response with a significant increase in the secretion of PGE₂, IL-6, IL-8 and MMP-1. Treatment of IL-1β stimulated fibroblasts in combination with PHMG-P or CHX at concentrations of 0.000045 or 0.0.00009% resulted in significantly decreased PGE₂, IL-6, IL-8 and MMP-1 levels. PHMG-P or CHX alone did not affect the baseline secretion of PGE₂, IL-6, IL-8 or MMP-1 by gingival fibroblasts.

CONCLUSIONS

Cytotoxic effects on gingival fibroblasts were triggered by both PHMG-P and CHX at concentrations below those used in clinical practice. The tested antiseptics did not cause inflammation and reduced IL-1β-induced secretion of inflammatory mediators and collagenase by gingival fibroblasts, which suggests anti-inflammatory properties.

The synthetic human beta-defensin-3 C15 peptide exhibits antimicrobial activity against Streptococcus mutans, both alone and in combination with dental disinfectants

Streptococcus mutans is a major etiologic agent of human dental caries that forms biofilms on hard tissues in the human oral cavity, such as tooth and dentinal surfaces. Human β-defensin-3 (HBD3) is a 45-amino-acid natural antimicrobial peptide that has broad spectrum antimicrobial activity against bacteria and fungi. A synthetic peptide consisting of the C-terminal 15 amino acids of HBD3 (HBD3-C15) was recently shown to be sufficient for its antimicrobial activity. Thus, clinical applications of this peptide have garnered attention. In this study, we investigated whether HBD3-C15 inhibits the growth of the representative cariogenic pathogen Streptococcus mutans and its biofilm formation. HBD3-C15 inhibited bacterial growth, exhibited bactericidal activity, and attenuated bacterial biofilm formation in a dose-dependent manner. HBD3-C15 potentiated the bactericidal and anti-biofilm activity of calcium hydroxide (CH) and chlorhexidine digluconate (CHX), which are representative disinfectants used in dental clinics, against S. mutans. Moreover, HBD3-C15 showed antimicrobial activity by inhibiting biofilm formation by S. mutans and other dentinophilic bacteria such as Enterococcus faecalis and Streptococcus gordonii, which are associated with dental caries and endodontic infection, on human dentin slices. These effects were observed for HBD3-C15 alone and for HBD3-C15 in combination with CH or CHX. Therefore, we suggest that HBD3-C15 is a potential alternative or additive disinfectant that can be used for the treatment of oral infectious diseases, including dental caries and endodontic infections.

Evaluation of the Efficacy of G32 (Commercially Available Ayurvedic Preparation) in Reducing Halitosis - A Randomized Controlled Trial

INTRODUCTION

Oral malodour is a social malady affecting people of all the age groups. Effective management of oral malodour is the key to improve the quality of life of such people.

AIM

To evaluate the effectiveness of ayurvedic medication, G32 in controlling oral malodour and comparing the effects with Chlorhexidine (CHX).

MATERIALS AND METHODS

This was a single blind randomized controlled trial with parallel study design conducted at a hospital in the city of Udupi in Southern India. A total of 40 patients suffering with oral malodour, aged 17-35 years, were included in this trial. After inclusion into the study, the subjects were examined twice, with a one-week interval between both examinations. Volatile Sulphur Compounds (VSCs), gingival, plaque and tongue coating scores were assessed at both examinations. Subjects were randomly allocated to G32 group - ayurvedic formulation (intervention group) and CHX group (control group), and were provided with the respective formulations enough to be used twice daily for a period of one week. The difference between the mean scores of VSCs, plaque, and gingivitis and tongue coating were compared within the intervention and control groups, respectively, using paired t-test.

RESULTS

Both test and control groups showed a significant reduction in VSCs, plaque and gingivitis levels. The percentage reductions in VSCs, plaque and gingivitis were found to be similar among the two groups. There was no significant difference between the preintervention and postintervention scores in both the groups.

CONCLUSION

G32, an ayurvedic medication, can be an effective tool to deal with oral malodour.

Comparative Evaluation of Antiplaque Efficacy between Essential Oils with Alcohol-Based and Chlorhexidine with Nonalcohol-Based Mouthrinses

Aim and Objectives:

The aim of this study is to compare the antiplaque efficacy of alcohol-based mouthwash with essential oils and nonalcohol-based chlorhexidine mouthrinse in 4 days plaque re-formation study.

Materials and Methods:

The current research paper is double-blinded, parallel designed clinical trial that was conducted in the Department of Periodontics and Oral Implantology, Kalinga Institute of Dental Sciences, Bhubaneswar. This included ninety dental students of Bachelor of Dental Surgery curriculum (in the age range from 20 to 24 years) Professional cleaning with scaling and polishing was carried out to acquire a zero plaque and gingival index (GI) for all ninety patients at baseline. Ninety patients were randomly divided into three groups with thirty patients in each group named as Group A, B, and C, respectively. Two commercially available mouthrinses, one containing alcohol (labeled as Solution (A) and one without alcohol (labeled as Solution (B) were placed in identical bottles and distributed to Group A and Group B patients. Whereas, the Group C patientswere instructed to use warm saline mouth rinse. The statistical analysis was performed using the Statistical Package for the Social Sciences software (Version 18).

Results:

Essential oils with an alcohol-based and chlorhexidine (CHX) alcohol-free mouthrinse (0.2%) groups compared to normal saline showed significant reductions in GI and PI scores.(P < 0.0001).

Conclusion:

The antiplaque efficacy of both alcohol-based mouthwash with essential oils and nonalcohol based CHX mouthwash were found to be equally effective in 4 days of plaque re-formation.

A broad-spectrum bactericidal lipopeptide with anti-biofilm properties

Previous studies of the oligoacyllysyl (OAK) series acyl-lysyl-lysyl-aminoacyl-lysine-amide, suggested their utility towards generating robust linear lipopeptide-like alternatives to antibiotics, although to date, none exhibited potent broad-spectrum bactericidal activity. To follow up on this premise, we produced a new analog (C₁₄KKc₁₂K) and investigated its properties in various media. Mechanistic studies suggest that C₁₄KKc₁₂K uses a non-specific membrane-disruptive mode of action for rapidly reducing viability of Gram-negative bacteria (GNB) similarly to polymyxin B (PMB), a cyclic lipopeptide used as last resort antibiotic. Indeed, C₁₄KKc₁₂K displayed similar affinity for lipopolysaccharides and induced cell permeabilization associated with rapid massive membrane depolarization. Unlike PMB however, C₁₄KKc₁₂K was also bactericidal to Gram-positive bacteria (GPB) at or near the minimal inhibitory concentration (MIC), as assessed against a multispecies panel of >50 strains, displaying MIC₅₀ at 3 and 6 µM, respectively for GPB and GNB. C₁₄KKc₁₂K retained activity in human saliva, reducing the viability of cultivable oral microflora by >99% within two minutes of exposure, albeit at higher concentrations, which, nonetheless, were similar to the commercial gold standard, chlorhexidine. This equipotent bactericidal activity was also observed in pre-formed biofilms of Streptococcus mutans, a major periodontal pathogen. Such compounds therefore, may be useful for eradication of challenging poly-microbial infections.

Effectiveness of disinfectants on the adherence of Candida albicans to denture base resins with different surface textures

The aim of the present study was to compare the effects of some disinfectants, including ethanol extract of propolis (EEP), on the adhesion of Candida albicans to denture base resins. Seventy-two acrylic resin samples were prepared, half of which was polished and the other half was roughened. C. albicans strain ATCC 10231 was incubated on Sabouraud dextrose agar (SDA) at 37°C for 48 h. The adhesion period was completed by keeping the cells in this suspension for 90 min at 37°C. Specimens were then immersed in the following solutions: 1%, 2%, and 5% sodium hypochlorite; 4% chlorhexidine gluconate; and 10% EEP. Quantification of the antifungal activity of the chemical solutions was performed using the colorimetric MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay test. One-way ANOVA and post-hoc Tukey tests were performed to evaluate the effectiveness of chemical agents. Polished and roughened surfaces were compared using independent sample t-test. The mean surface roughness value was 0.35 (±0.04) µm for the polished group and 1.2 (±0.2) µm for the roughened group. The contact angles of both surfaces showed statistically significant difference, and 10% EEP solution exhibited significantly less removal of adherent viable C. albicans cells in both groups. All forms of sodium hypochlorite solutions yielded higher efficiency than 4% chlorhexidine gluconate and EEP solutions (P < 0.05). (J Oral Sci 58, 431-437, 2016).

Chlorhexidine mouthrinse as an adjunctive treatment for gingival health

BACKGROUND

Dental plaque associated gingivitis is a reversible inflammatory condition caused by accumulation and persistence of microbial biofilms (dental plaque) on the teeth. It is characterised by redness and swelling of the gingivae (gums) and a tendency for the gingivae to bleed easily. In susceptible individuals, gingivitis may lead to periodontitis and loss of the soft tissue and bony support for the tooth. It is thought that chlorhexidine mouthrinse may reduce the build-up of plaque thereby reducing gingivitis.

OBJECTIVES

To assess the effectiveness of chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for the control of gingivitis and plaque compared to mechanical oral hygiene procedures alone or mechanical oral hygiene procedures plus placebo/control mouthrinse. Mechanical oral hygiene procedures were toothbrushing with/without the use of dental floss or interdental cleaning aids and could include professional tooth cleaning/periodontal treatment.To determine whether the effect of chlorhexidine mouthrinse is influenced by chlorhexidine concentration, or frequency of rinsing (once/day versus twice/day).To report and describe any adverse effects associated with chlorhexidine mouthrinse use from included trials.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 28 September 2016); the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8) in the Cochrane Library (searched 28 September 2016); MEDLINE Ovid (1946 to 28 September 2016); Embase Ovid (1980 to 28 September 2016); and CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 28 September 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for at least 4 weeks on gingivitis in children and adults. Mechanical oral hygiene procedures were toothbrushing with/without use of dental floss or interdental cleaning aids and could include professional tooth cleaning/periodontal treatment. We included trials where participants had gingivitis or periodontitis, where participants were healthy and where some or all participants had medical conditions or special care needs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where feasible. For continuous outcomes, we used means and standard deviations to obtain the mean difference (MD) and 95% confidence interval (CI). We combined MDs where studies used the same scale and standardised mean differences (SMDs) where studies used different scales. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs. Due to anticipated heterogeneity we used random-effects models for all meta-analyses.

MAIN RESULTS

We included 51 studies that analysed a total of 5345 participants. One study was assessed as being at unclear risk of bias, with the remaining 50 being at high risk of bias, however, this did not affect the quality assessments for gingivitis and plaque as we believe that further research is very unlikely to change our confidence in the estimate of effect. Gingivitis After 4 to 6 weeks of use, chlorhexidine mouthrinse reduced gingivitis (Gingival Index (GI) 0 to 3 scale) by 0.21 (95% CI 0.11 to 0.31) compared to placebo, control or no mouthrinse (10 trials, 805 participants with mild gingival inflammation (mean score 1 on the GI scale) analysed, high-quality evidence). A similar effect size was found for reducing gingivitis at 6 months. There were insufficient data to determine the reduction in gingivitis associated with chlorhexidine mouthrinse use in individuals with mean GI scores of 1.1 to 3 (moderate or severe levels of gingival inflammation). Plaque Plaque was measured by different indices and the SMD at 4 to 6 weeks was 1.45 (95% CI 1.00 to 1.90) standard deviations lower in the chlorhexidine group (12 trials, 950 participants analysed, high-quality evidence), indicating a large reduction in plaque. A similar large reduction was found for chlorhexidine mouthrinse use at 6 months. Extrinsic tooth staining There was a large increase in extrinsic tooth staining in participants using chlorhexidine mouthrinse at 4 to 6 weeks. The SMD was 1.07 (95% CI 0.80 to 1.34) standard deviations higher (eight trials, 415 participants analysed, moderate-quality evidence) in the chlorhexidine mouthrinse group. There was also a large increase in extrinsic tooth staining in participants using chlorhexidine mouthrinse at 7 to 12 weeks and 6 months. Calculus Results for the effect of chlorhexidine mouthrinse on calculus formation were inconclusive. Effect of concentration and frequency of rinsing There were insufficient data to determine whether there was a difference in effect for either chlorhexidine concentration or frequency of rinsing. Other adverse effects The adverse effects most commonly reported in the included studies were taste disturbance/alteration (reported in 11 studies), effects on the oral mucosa including soreness, irritation, mild desquamation and mucosal ulceration/erosions (reported in 13 studies) and a general burning sensation or a burning tongue or both (reported in nine studies).

AUTHORS' CONCLUSIONS

There is high-quality evidence from studies that reported the Löe and Silness Gingival Index of a reduction in gingivitis in individuals with mild gingival inflammation on average (mean score of 1 on the 0 to 3 GI scale) that was not considered to be clinically relevant. There is high-quality evidence of a large reduction in dental plaque with chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for 4 to 6 weeks and 6 months. There is no evidence that one concentration of chlorhexidine rinse is more effective than another. There is insufficient evidence to determine the reduction in gingivitis associated with chlorhexidine mouthrinse use in individuals with mean GI scores of 1.1 to 3 indicating moderate or severe levels of gingival inflammation. Rinsing with chlorhexidine mouthrinse for 4 weeks or longer causes extrinsic tooth staining. In addition, other adverse effects such as calculus build up, transient taste disturbance and effects on the oral mucosa were reported in the included studies.

Effectiveness of a pre-procedural mouthwash in reducing bacteria in dental aerosols: randomized clinical trial

The aim of this randomized, single blinded clinical trial was to evaluate the effect of a pre-procedural mouthwash containing cetylpyridinium chloride (CPC), zinc lactate (Zn) and sodium fluoride (F) in the reduction of viable bacteria in oral aerosol after a dental prophylaxis with ultrasonic scaler. Sixty systemically healthy volunteers receiving dental prophylaxis were randomly assigned to one of the following experimental groups (15 per group): (i) rinsing with 0.075% CPC, 0.28% Zn and 0.05% F (CPC+Zn+F), (ii) water or (iii) 0.12% chlorhexidine digluconate (CHX), and (iv) no rinsing. Viable bacteria were collected from different locations in the dental office on enriched TSA plates and anaerobically incubated for 72 hours. The colonies were counted and species were then identified by Checkerboard DNA-DNA Hybridization. The total number of colony-forming units (CFUs) detected in the aerosols from volunteers who rinsed with CPC+Zn+F or CHX was statistically significantly (p<0.05) lower than of those subjects who did not rinse or who rinsed with water. When all locations were considered together, the aerosols from the CPC+Zn+F and CHX groups showed, respectively, 70% and 77% fewer CFUs than those from the No Rinsing group and 61% and 70% than those from the Water group. The mean proportions of bacterial species from the orange complex were statistically significantly (p<0.05) lower in aerosols from the CPC+Zn+F and CHX groups compared with the others two groups. In conclusion, the mouthwash containing CPC+Zn+F, is effective in reducing viable bacteria in oral aerosol after a dental prophylaxis with ultrasonic scaler.

Chlorhexidine mouthwash as an adjunct to mechanical therapy in chronic periodontitis: A meta-analysis

BACKGROUND

Through a systematic literature review, the authors evaluated the use of chlorhexidine (CHX) mouthwash as an adjunct to mechanical periodontal therapy for chronic periodontitis.

TYPES OF STUDIES REVIEWED

The authors performed a systematic search by using PubMed (MEDLINE), Scopus, Scientific Electronic Library Online, and Cochrane Central Register of Controlled Trials. The authors selected randomized controlled clinical trials in which the investigators evaluated the probing depth (PD) and clinical attachment level (CAL) in test groups by using CHX as an adjuvant and in control groups and subject to mechanical periodontal therapy (scaling and root planing [SRP] 4-6 visits or 24 hours).

RESULTS

The literature search resulted in 8 articles, which the authors then assessed for quality. After testing for heterogeneity, the authors performed a meta-analysis only in the SRP group with 4 to 6 visits. Results were positive for both PD and CAL with use of CHX. However, the summary measure was significant (P < .05) only for PD at 40 to 60 days (0.33 millimeters; 95% confidence interval, 0.08 to 0.58 mm) and 180 days (0.24 mm; 95% confidence interval, 0.02 to 0.47 mm) of follow-up, showing positive results for the use of CHX at those times. Although those differences were statistically significant, they could be interpreted as clinically slight.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Adjunctive use of CHX mouthrinse with mechanical SRP resulted in slightly greater PD reduction than did SRP alone. Clinicians must consider the small additional gain in PD reduction, negligible effect on CAL, and potential for tooth staining when using CHX as an adjunct to SRP in treating chronic periodontitis.

A review of the recent advances in antimicrobial coatings for urinary catheters

More than 75% of hospital-acquired or nosocomial urinary tract infections are initiated by urinary catheters, which are used during the treatment of 15-25% of hospitalized patients. Among other purposes, urinary catheters are primarily used for draining urine after surgeries and for urinary incontinence. During catheter-associated urinary tract infections, bacteria travel up to the bladder and cause infection. A major cause of catheter-associated urinary tract infection is attributed to the use of non-ideal materials in the fabrication of urinary catheters. Such materials allow for the colonization of microorganisms, leading to bacteriuria and infection, depending on the severity of symptoms. The ideal urinary catheter is made out of materials that are biocompatible, antimicrobial, and antifouling. Although an abundance of research has been conducted over the last forty-five years on the subject, the ideal biomaterial, especially for long-term catheterization of more than a month, has yet to be developed. The aim of this review is to highlight the recent advances (over the past 10years) in developing antimicrobial materials for urinary catheters and to outline future requirements and prospects that guide catheter materials selection and design.

STATEMENT OF SIGNIFICANCE

This review article intends to provide an expansive insight into the various antimicrobial agents currently being researched for urinary catheter coatings. According to CDC, approximately 75% of urinary tract infections are caused by urinary catheters and 15-25% of hospitalized patients undergo catheterization. In addition to these alarming statistics, the increasing cost and health related complications associated with catheter associated UTIs make the research for antimicrobial urinary catheter coatings even more pertinent. This review provides a comprehensive summary of the history, the latest progress in development of the coatings and a brief conjecture on what the future entails for each of the antimicrobial agents discussed.

Reduced susceptibility to chlorhexidine disinfectant among New Delhi metallo-beta-lactamase-1 positive Enterobacteriaceae and other multidrug-resistant organisms: Report from a tertiary care hospital in Karachi, Pakistan

We analysed susceptibility of multidrug-resistant organisms (MDROs) including New Delhi metallo-beta-lactamase-1 positive Enterobacteriaceae to chlorhexidine and compared results to their susceptible counterparts. Susceptibilities of chlorhexidine digluconate in a standard (CHX-S) preparation and two commercial disinfectants containing different CHX concentrations (2% w/v and 4% w/w) were performed. MDROs had narrower range of higher CHX-S minimum inhibitory concentrations (MICs) as compared to pan-sensitive organisms. The MIC values for commercial disinfectants products for MDROs were many folds higher (20-600 times), than CHX-S for in vitro use. Increasing antibiotic resistance among bacterial isolates can be an indirect marker of reduced susceptibility to chlorhexidine in hospital setting.

A randomised clinical study to evaluate the efficacy of alcohol-free or alcohol-containing mouthrinses with chlorhexidine on gingival bleeding

Investigates the efficacy and tolerability of alcohol-free and alcohol-containing chlorhexidine mouthrinses.

Discusses the pharmacokinetics of alcohol-free and alcohol-containing chlorhexidine mouthrinses after single and repeated use.

Objectives Gingival bleeding following twice-daily use of 0.2% w/v chlorhexidine digluconate mouthrinse with and without alcohol (0.2% CHX-alcohol; 0.2% CHX-alcohol-free, respectively) and brushing with a standard fluoride toothpaste was compared to brushing alone.

Methods Three hundred and nineteen subjects with mild-to-moderate gingivitis (with ≥16 gradable permanent teeth including four molars, bleeding after brushing and ≥20 bleeding sites) completed this randomised, examiner-blinded, parallel-group study. A prophylaxis was performed at baseline. Gingival Severity Index (GSI; primary objective), Gingival Index (GI) and Plaque Index (PI) were assessed at baseline and after 6 weeks of treatment. Adverse events (AEs) were recorded throughout the study.

Results Between treatment differences at week 6 demonstrated significantly lower GSI for the 0.2% CHX-alcohol and 0.2% CHX-alcohol-free groups compared to brushing alone (primary endpoint; treatment difference −0.061 [95% CI −0.081, −0.041] and −0.070 [95% CI −0.090, −0.050], respectively; both p <0.0001). There were also significant reductions in GI and PI for the 0.2% CHX-alcohol and 0.2% CHX-alcohol-free groups compared to brushing alone (all p <0.0001). The proportion of subjects reporting ≥1 treatment-related adverse events (TRAEs) was 27.8% (0.2% CHX-alcohol), 24.8% (0.2% CHX-alcohol-free) and 3.7% (brushing alone).

Conclusions Chlorhexidine mouthrinse with or without alcohol as an adjunct to brushing with regular fluoride toothpaste significantly reduces bleeding scores, plaque and gingival inflammation compared to brushing alone. TRAEs are characteristic of those associated with the use of chlorhexidine and are similar for both mouthrinses.

A comparative evaluation of the efficacy of curcumin and chlorhexidine mouthrinses on clinical inflammatory parameters of gingivitis: A double-blinded randomized controlled clinical study

Aim:

The aim of this study was to assess the efficacy of 0.1% curcumin mouthwash and to compare it with 0.2% chlorhexidine gluconate as an antiplaque agent and its effect on gingival inflammation.

Materials and Methods:

One hundred and fifty subjects, age between 20 and 30 years were recruited. Study population were randomly divided into three groups. In Group A, 50 subjects were advised the experimental mouthwash. Group B subjects used placebo mouthrinse, and chlorhexidine mouth wash was given to Group C. The subjects were advised to use 10 ml of mouthwash for 1 min twice a day 30 min after brushing. Parameters were recorded for plaque, gingival, and sulcus bleeding indices at day 0, 7, 14, and 28 days along with subjective assessment of taste.

Results:

On intragroup comparison between curcumin, chlorhexidine, and placebo mouthwash, the mean percentage reduction of the plaque index (PI) between 0 and 28 days were 0.58,0.57 and 1.17, respectively (P < 0.01), percentage reduction of gingival index (GI) between 0 and 28 days were 0.65, 0.66, and 1.09, respectively (P < 0.01) and sulcus bleeding index (SBI) showed a percentage reduction of 0.69, 0.66, and 1.13, respectively The intergroup comparison revealed chlorhexidine and curcumin mouthwash were statistically significant with P < 0.001 as compared to placebo.

Conclusion:

Curcumin mouthwash has shown an antiplaque and antigingivitis properties comparable to chlorhexidine mouthwash. Thus, curcumin mouthwash and chlorhexidine gluconate can be effectively used as an adjunct to scaling and root planning.

Drug loaded poly(glycerol sebacate) as a local drug delivery system for the treatment of periodontal disease

A simple, cost-efficient method to load drugs into poly(glycerol sebacate) polymer. Drugs were able to sustained release for up to 60 days. The drugs loaded polymer showed cytocompatibility and antimicrobial activities.

Gingivitis and plaque prevention using three commercially available dentifrices: A comparative clinical and microbiological randomized control parallel study

Aim:

The aim of the study was to compare the clinical and microbiological efficacy of Group I-delmopinol dentifrice, Group II-chlorhexidine, and Group III-triclosan-containing regularly used control dentifrice on plaque formation and gingivitis.

Materials and Methods:

A total of 45 healthy volunteer students fulfilling the inclusion criteria are recruited for this randomized control parallel study. All the individuals were randomly assigned into 3 groups depending on the dentifrice prescribed. After the selection of individuals, thorough scaling and polishing were performed for all the individuals, and in a 4 days' washout period, they were refrained from regular oral hygiene maintenance and 0.9% NaCl (normal saline) rinse was prescribed to obtain plaque regrowth. Microbiological morphotypes were assessed using darkfield microscope.

Statistical Analysis:

The data were analyzed using the SPSS-software 19.00 program. The intragroup comparison of clinical parameters was done using Kruskal–Wallis ANOVA test, and intergroup comparison was done by Mann–Whitney U-test. The intragroup comparison of clinical parameters including modified staining index, the supragingival microbiota such as cocci, bacilli, and spirochetes scores was done at various study intervals using one-way ANOVA, and intergroup comparison was done using Tukey's multiple post hoc test.

Results:

The results showed that statistically significant correlation between Group II and Group III at 15 and 30 days and between Group I and Group II at 30 days with cocci and bacilli but not spirochetes.

Conclusion:

Group II showed better plaque and gingivitis reduction compared to other active groups. To validate the results of the present study, further long-term studies with larger sample size and evaluation using known and proven study designs on gingivitis patients are needed.

Chlorhexidine possesses unique cytotoxic actions in rat thymic lymphocytes: Its relation with electrochemical property of membranes

Chlorhexidine (CHX) is an antibacterial agent used in various types of pharmaceutical products. Therefore, CHX is easily found around us. Owing to its positive charge, the electrochemical property of cell membranes was assumed to be a key point of cytotoxic action of CHX. Depolarization of membranes attenuated the cytotoxic action of CHX in rat thymic lymphocytes. CHX interfered with annexin V binding to membranes. Manipulations to induce exposure of phosphatidylserine on the outer membrane surface augmented the cytotoxic action of CHX, indicating that changes in the electrochemical property of membranes affected the cytotoxic action of CHX. Hence, CHX might kill cells physiologically undergoing apoptosis, resulting instead in necrotic cell death. However, the threshold CHX concentration in this in vitro study was slightly higher than blood CHX concentrations observed clinically. Therefore, these results may support the safety of CHX use although CHX possesses unique cytotoxic actions described in this study.

Evaluation of new chlorhexidine- and cetylpyridinium chloride-based mouthrinse formulations adjunctive to scaling and root planing: pilot study

OBJECTIVE

To compare the effect of two newly formulated chlorhexidine (CHX) and cetylpyridinium chloride (CPC) mouthrinses after scaling and root planing (SRP) in terms of clinical, microbiological, patient-based variables and adverse events, with a positive control with the same active components, already marketed and tested.

METHODS

A pilot, randomized clinical trial, double-blind, parallel design with 1-month follow-up was conducted. Chronic periodontitis patients requiring non-surgical periodontal therapy were enrolled and randomly assigned to: (i) SRP and test-1 (new reformulation: 0.12% CHX and 0.05% CPC); (ii) SRP and test-2 (new formulation: 0.03% CHX and 0.05% CPC); or (iii) SRP and positive control (commercial product: 0.12% CHX and 0.05% CPC). All variables were evaluated at baseline and 1 month after SRP. Quantitative variables were compared by means of anova or Kruskal-Wallis test and qualitative variables by chi-square or McNemar tests.

RESULTS

Thirty patients (10 per group) were included. After 1 month, there were significant differences among groups in plaque levels (P = 0.016) as test-1 showed less sites with plaque than test-2 (31.15% [standard error-SE 2.21%] versus 49.39% [SE 4.60%), respectively). No significant differences were found for global patient perception of the product or in adverse effects. Test groups showed better results in levels and proportions (P = 0.022) of Capnocytophaga spp.

CONCLUSIONS

Within the limitations of this pilot study, it can be concluded that the newly formulated 0.12% CHX and 0.05% CPC mouthrinse showed larger plaque level reductions, without showing more adverse effects, when compared to the other two mouthrinses, after SRP.

Anti-biofilm and bactericidal effects of magnolia bark-derived magnolol and honokiol on Streptococcus mutans

Dental caries affects people of all ages and is a worldwide health concern. Streptococcus mutans is a major cariogenic bacterium because of its ability to form biofilm and induce an acidic environment. In this study, the antibacterial activities of magnolol and honokiol, the main constituents of the bark of magnolia plants, toward planktonic cell and biofilm of S. mutans were examined and compared with those of chlorhexidine. The minimal inhibitory concentrations of magnolol, honokiol and chlorhexidine for S. mutans were 10, 10 and 0.25 µg/mL, respectively. In addition, each agent showed bactericidal activity against S. mutans planktonic cells and inhibited biofilm formation in a dose- and time-dependent manner. Magnolol (50 µg/mL) had greater bactericidal activity against S. mutans biofilm than honokiol (50 µg/mL) and chlorhexidine (500 µg/mL) at 5 min after exposure, while all showed scant activity against biofilm at 30 s. Furthermore; chlorhexidine (0.5-500 µg/mL) exhibited high cellular toxicity for the gingival epithelial cell line Ca9-22 at 1 hr, whereas magnolol (50 µg/mL) and honokiol (50 µg/mL) did not. Thus; it was found that magnolol has antimicrobial activities against planktonic and biofilm cells of S. mutans. Magnolol may be a candidate for prevention and management of dental caries.

Betulin inhibits cariogenic properties of Streptococcus mutans by targeting vicRK and gtf genes

Streptococcus mutans, a multivirulent pathogen is considered the primary etiological agent in dental caries. Development of antibiotic resistance in the pathogen has created a need for novel antagonistic agents which can control the virulence of the organism and reduce resistance development. The present study demonstrates the in vitro anti-virulence potential of betulin (lup-20(29)-ene-3β,28-diol), an abundantly available plant triterpenoid against S. mutans UA159. Betulin exhibited significant dose dependent antibiofilm activity without affecting bacterial viability. At 240 µg/ml (biofilm inhibitory concentration), betulin inhibited biofilm formation and adherence to smooth glass surfaces by 93 and 71 % respectively. It reduced water insoluble glucan synthesis by 89 %, in conjunction with down regulation of gtfBC genes. Microscopic analysis confirmed the disruption in biofilm architecture and decreased exopolysaccharide production. Acidogenicity and aciduricity, key virulence factors responsible for carious lesions, were also notably affected. The induced auto-aggregation of cells upon treatment could be due to the down regulation of vicK. Results of gene expression analysis demonstrated significant down-regulation of virulence genes upon betulin treatment. Furthermore, the nontoxic effect of betulin on peripheral blood mononuclear cells even after 72 h treatment makes it a strong candidate for assessing its suitability to be used as a therapeutic agent.

Enzymes in therapy of biofilm-related oral diseases

Biofilm-related infections of the oral cavity, including dental caries and periodontitis, represent the most prevalent health problems. For years, the treatment thereof was largely based on antibacterial chemical agents. Recently, however, there has been growing interest in the application of more preventive and minimally invasive biotechnological methods. This review focuses on the potential applications of enzymes in the treatment and prevention of oral diseases. Dental plaque is a microbial community that develops on the tooth surface, embedded in a matrix of extracellular polymeric substances of bacterial and host origin. Both cariogenic microorganisms and the key components of oral biofilm matrix may be the targets of the enzymes. Oxidative salivary enzymes inhibit or limit the growth of oral pathogens, thereby supporting the natural host defense system; polysaccharide hydrolases (mutanases and dextranases) degrade important carbohydrate components of the biofilm matrix, whereas proteases disrupt bacterial adhesion to oral surfaces or affect cell-cell interactions. The efficiency of the enzymes in in vitro and in vivo studies, advantages and limitations, as well as future perspectives for improving the enzymatic strategy are discussed.

Chlorhexidine Loaded Cyclodextrin Containing PMMA Nanogels as Antimicrobial Coating and Delivery Systems

Antimicrobial nanogels, aggregates, and films are prepared by complexation of the antiseptic and bacteriostatic agent chlorhexidine (CHX) for medical and dental applications. A series of α-, β-, and γ-cyclodextrin methacrylate (CD-MA) containing hydrophobic poly(methyl methacrylate) (PMMA) based nanogels are loaded quantitatively with CHX in aqueous dispersion. The results show that CHX is enhancedly complexed by the use of CD-MA domains in the particles structure. β-CD-MA nanogels present the highest uptake of CHX. Furthermore, it is observed that the uptake of CHX in nanogels is influenced by the hydrophobic PMMA structure. CHX acts as external cross-linker of nanogels by formation of 1:2 (CHX:CD-MA) inclusion complexes of two β-CD-MA units on the surfaces of two different nanogels. The nanogels adsorb easily onto glass surfaces by physical self-bonding and formation of a dense crosslinked nanogel film. Biological tests of the applied CHX nanogels with regard to antimicrobial efficiency are successfully performed against Staphylococcus aureus.

Chlorhexidine-induced elastic and adhesive changes of Escherichia coli cells within a biofilm

Chlorhexidine is a widely used, commercially available cationic antiseptic. Although its mechanism of action on planktonic bacteria has been well explored, far fewer studies have examined its interaction with an established biofilm. The physical effects of chlorhexidine on a biofilm are particularly unknown. Here, the authors report the first observations of chlorhexidine-induced elastic and adhesive changes to single cells within a biofilm. The elastic changes are consistent with the proposed mechanism of action of chlorhexidine. Atomic force microscopy and force spectroscopy techniques were used to determine spring constants and adhesion energy of the individual bacteria within an Escherichia coli biofilm. Medically relevant concentrations of chlorhexidine were tested, and cells exposed to 1% (w/v) and 0.1% more than doubled in stiffness, while those exposed to 0.01% showed no change in elasticity. Adhesion to the biofilm also increased with exposure to 1% chlorhexidine, but not for the lower concentrations tested. Given the prevalence of chlorhexidine in clinical and commercial applications, these results have important ramifications on biofilm removal techniques.

The antiplaque efficacy of white tea extract mouthrinse

Objective:

This study was conducted to assess the antiplaque efficacy of a mouthwash containing white tea. It also assessed the antibacterial properties of white tea against Prevotella intermedia (Pi), Porphyromonas gingivalis (Pg), and Aggregatibacter actinomycetemcomitans (Aa) in vitro.

Materials and Methods:

Forty-five subjects with healthy periodontium were randomly chosen and were divided into three groups and advised to use mouthwashes A, B, and C (Group A, white tea; Group B, distilled water [placebo]; Group C, chlorhexidine) for 4 days. They were advised to refrain from any kind of mechanical oral hygiene techniques. Plaque index (PI) was checked on day 1 and 5. In vitro testing for against Pi, Pg, and Aa against white tea extract was undertaken.

Results:

PI significantly increased from day 1 to day 5 (P < 0.01) in Groups A, B, and C. In inter-group comparison, there was a statistical significant difference between white tea mouthrinse group and placebo group, chlorhexidine group and placebo group and also chlorhexidine group and white tea mouthrinse group. However, chlohexidine showed superior antiplaque activity. In vitro test, white tea showed effective inhibition against all three bacterial strains Pi, Pg, and Aa at 1% concentration.

Conclusion:

White tea mouthrinse potently inhibits plaque formation although not as comparable to chlorhexidine mouthrinse. Hence, for those preferring herbal products, white tea mouthrinse is a good option.

Antimicrobial effect of chlorhexidine on Aggregatibacter actinomycetemcomitans biofilms associated with peri-implantitis

Background. This study aimed to assessthe antimicrobial effect of chlorhexidine (CHX) on Aggregatibacter actinomycetemcomitans biofilms isolated from subgingival plaque of peri-implantitis lesions.

Methods. Thirteen patients requiring peri-implantitis treatment were consecutively selected and their subgingival biofilm was collected by inserting fine sterile paper points into peri-implant pockets for 15 seconds. A. actinomycetemcomitans was isolated from the subgingival biofilm and cultured. In this study, the standard strain of A. actinomycetemcomitans served as the positive control group and a blank disc impregnated with water served as the negative control; 0.1 mL of the bacterial suspension was cultured on specific culture medium and blank discs (6 mm in diameter) impregnated with 0.2%CHX mouthrinse (Behsa Pharmaceutical Co.) and negative control discs were placed on two sides of the bacterial culture plate. The size of growth inhibition zone was measured by a blinded independent observer in millimetres.

Results. According to the results of disc diffusion test, the mean diameter of growth inhibition zone of A. actinomycetemcomitans around discs impregnated with CHX was larger in both standard (positive control) and biofilm samples of A. actinomycetemcomitans compared to the negative control group (blank disc) (P<0.001).

Conclusion. Use of0.2% CHX mouthwash had antibacterial effects on A. actinomycetemcomitans species isolated from peri-implantitis sites.

Antimicrobial activity of toothpastes containing natural extracts, chlorhexidine or triclosan

The objective of this in vitro study was to evaluate the antimicrobial effect of toothpastes containing natural extracts, chlorhexidine or triclosan. The effectiveness of toothpastes containing natural extracts (Parodontax®), 0.12% chlorhexidine (Cariax®), 0.3% triclosan (Sanogil®) or fluoride (Sorriso®, control) was evaluated against yeasts, Gram-positive and Gram-negative bacteria using the disk diffusion method. Water was used as a control. Disks impregnated with the toothpastes were placed in Petri dishes containing culture media inoculated with 23 indicative microorganisms by the pour plate method. After incubation, the inhibition growth halos were measured and statistical analyses (α=0.05) were performed. The results indicated that all formulations, except for conventional toothpaste (Sorriso®), showed antimicrobial activity against Gram-positive bacteria and yeasts. The toothpaste containing natural extracts (Parodontax®) was the only product able to inhibit the growth of Pseudomonas aeruginosa. The toothpastes containing chlorhexidine, triclosan or natural extracts presented antimicrobial activity against Gram-positive bacteria and yeasts.

Establishment and maintenance of asepsis in endodontics - a review of the literature

OBJECTIVES

Successful endodontic treatment depends on effective measures to eliminate and prevent infection of root canals. Initially treatment should start with isolation and disinfection of the operating field. This review makes an inventory of the available knowledge regarding its establishment and maintenance.

MATERIALS AND METHODS

A literature search was conducted in the PubMed database in order to identify clinical trials examining disinfection or unintentional contamination of the endodontic operative field. A list of 115 articles was obtained and screened. Five relevant articles were identified. These articles were read in full text. The reference lists from these articles were checked manually for additional studies and three studies were obtained. A total of eight articles met the inclusion criteria.

RESULTS

There was a great variety in terms of aim, method, and material of the included studies. None could prove a totally reliable aseptic operative field and not one chemical, or combination of chemicals, were found in more than one study.

CONCLUSIONS

No study documented complete asepsis following initial disinfection, and no study could document predictable maintenance of an established bacteria-free surface. Critical appraisal and standardization of the disinfection and aseptic procedures in endodontics are needed.

Triphala, a New Herbal Mouthwash for the Treatment of Gingivitis: A Randomized Controlled Clinical Trial

BACKGROUND

An antiplaque agent with minimal side effects that can be used as an effective adjunct to mechanical plaque control is needed. The current study is designed to evaluate efficacy of triphala (TRP) mouthwash in reduction of plaque and gingivitis.

METHODS

Ninety individuals with chronic generalized gingivitis were randomly assigned to three groups: 1) group I, placebo mouthwash; 2) group II, TRP mouthwash; and 3) group III, chlorhexidine (CHX) mouthwash. All individuals were instructed to rinse with their respective mouthwash twice daily. 1) Plaque index (PI); 2) gingival index (GI); 3) oral hygiene index-simplified (OHI-S); and 4) microbiologic colony counts were recorded at baseline and at 7, 30, and 60 days.

RESULTS

All three groups showed gradual reduction in PI, GI, and OHI-S levels from baseline to 7, 30, and 60 days. There was also significant reduction in microbial counts in all groups at all time intervals except in group I. A significant difference was noticed with respect to reduction in PI, GI, OHI-S, and microbiologic counts in group I compared with groups II and III. However, no significant differences were found between groups II and III for any parameters at any time intervals.

CONCLUSIONS

TRP mouthwash was found to decrease inflammatory parameters from baseline to follow-up intervals. Because improvement in gingivitis was comparable with that of CHX mouthwash, TRP mouthwash can be considered a potential therapeutic agent in the treatment of gingivitis.