Chlorhexidine: is it still the gold standard?

Effect of daily manual toothbrushing with 0.2% chlorhexidine gel on pneumonia-associated pathogens in adults living with profound neuro-disability

Purpose

To investigate the effect of daily toothbrushing with 0.2 % chlorhexidine digluconate (CHX) on the colonization of dental plaque by pathogens associated with pneumonia amongst non-ventilated adults with a neuro-disability.

Methodology

Forty-nine patients living in long-term care were recruited. Daily toothbrushing with 0.2 % CHX gel was conducted for 48 weeks. Plaque accumulation was assessed and microbiological sampling was undertaken every 6 weeks.

Results

At any one time point at least 65 % (n=32) of subjects were found to harbour respiratory pathogens. Although there were significant changes in the proportion of individuals colonized over time with Gram-negative bacilli and Pseudomonas aeruginosa, the changes were not sustained. By week 48 there was no significant difference from the levels that had been recorded at baseline.

Conclusions

Bacteria known to be causal in pneumonia are present and colonize the dental plaque of non-ventilated adults with a neuro-disability. Daily toothbrushing with 0.2 % CHX gel did not produce a sustained reduction in intra-oral respiratory pathogen counts after 48 weeks.

Mouthwash Effects on LGG-Integrated Experimental Oral Biofilms

In order to investigate the effects of mouthwashes on oral biofilms with probiotics, we compared in biofilms the susceptibility to mouthwashes of probiotic Lactobacillus rhamnosus GG (LGG) and oral pathogens Streptococcus mutans, Streptococcus sanguinis, and Candida albicans. We also evaluated these pathogens’ susceptibility to the mouthwashes and their recovery after mouthwash-rinsing in biofilms with/without LGG. First, 1-day-/3-day-old LGG-integrated multi-species biofilms were exposed for 1 min to mouthwashes containing chlorhexidine, essential oils, or amine fluoride/stannous fluoride. Cells were plate-counted and relative survival rates (RSRs) of LGG and pathogens calculated. Second, 1-day-/3-day-old multispecies biofilms with and without LGG were exposed for 1 min to mouthwashes; cells were plate-counted and the pathogens’ RSRs were calculated. Third, 1-day-old biofilms were treated for 1 min with mouthwashes. Cells were plate-counted immediately and after 2-day cultivation. Recovery rates of pathogens were calculated and compared between biofilms with/without LGG. Live/Dead^® staining served for structural analyses. Our results showed that RSRs of LGG were insignificantly smaller than those of pathogens in both 1-day and 3-day biofilms. No significant differences appeared in pathogens’ RSRs and recovery rates after treatment between biofilms with/without LGG. To conclude, biofilm LGG was susceptible to the mouthwashes; but biofilm LGG altered neither the mouthwash effects on oral pathogens nor affected their recovery.

Chlorhexidine: An Elixir for Periodontics

Chlorhexidine is a cationic bisbiguanide with broad antibacterial activity, and wide spectrum of activity encompassing gram-positive and gram-negative bacteria, yeasts, dermatophytes and some lipophilic viruses. Its antibacterial action is due to the disruption of the bacterial cell membrane by the chlorhexidine molecules, increasing the permeability and resulting in cell lysis. Thus, chlorhexidine plays a key role in the dentistry and is used to treat or prevent periodontal disease, and has earned its eponym of the gold standard. This article reviews in detail about the mechanism of action, indications, forms and various studies related to chlorhexidine.

Postoperative effects of intra-alveolar application of 0.2% chlorhexidine or 1% hyaluronic acid bioadhesive gels after mandibular third molar extraction: a double-blind randomized controlled clinical trial

OBJECTIVE

The aim of this study was to analyze the postoperative effects of intra-alveolar applications of 0.2% chlorhexidine (CHL) or 1% hyaluronic (HA) acid bioadhesive gels following the extraction of mandibular impacted third molars (MITMs).

MATERIALS AND METHODS

In this double-blind randomized controlled clinical trial, 90 patients with one asymptomatic MITM were randomized into three group (n = 30 per group): group 1 (0.2% CHL), group 2 (1% HA), and group 3 (control). Visual analogue scales (VAS) were used to assess postoperative pain 24, 48, and 72 h and 7 days after surgery. Postsurgical complications were recorded: trismus, alveolitis osteitis, infection, or hematoma.

RESULTS

In order from least to greatest, postoperative pain at all evaluation times was 0.2% CHL < 1% HA < control. At 24 h, statistically significant differences were found between both study groups and the control groups (0.2% CHL/control: P = 0.001; 1% HA/control: P = 0.010). At 48 and 72 h, significant differences were only found between 0.2% CHL and the control group (P = 0.229 and P = 0.046, respectively). At 7 days, no significant differences were found between any groups. Comparing the incidence of postoperative trismus, alveolitis osteitis, infection, or hematoma, although complications were more frequent in the control group, no statistical differences between groups were found (P > 0.050).

CONCLUSIONS

Both 0.2% CHL and 1% HA bioadhesive gels applied intra-alveolarly minimize the postoperative complications after MITM extraction. Further research is necessary to confirm the present results.

CLINICAL RELEVANCE

This study might help to reduce the postsurgical complications in patients after MITM extraction.

Morphological and chemical analysis of surface interaction of irrigant-endosequence root repair material

This study aimed to evaluate the characterization of chemical interaction of root canal irrigants on the surface of EndoSequence root repair materials using spectroscopy analysis. Round discs of putty and paste were obtained and immersed in saline, sodium hypochlorite (NaOCl), or chlorhexidine. On the surface of chlorhexidine treated putty, diffuse red pigmentation was detected by Raman analysis and diffuse black pigmentation having unusual needle-like shaped crystals was detected by scanning electron microscopy. This pigmentation formed from nitrogen-rich compounds detected by Raman, infrared spectroscopy, and X-ray diffraction analysis. Mineral/amide ratios were increased by NaOCl and significantly decreased by chlorhexidine. Carbonate/phosphate ratios showed no significant changes by NaOCl, while a significant decrease by chlorhexidine. A full half of maximum width_Raman of the phosphate band was significantly increased by NaOCl, while decreased by chlorhexidine. In conclusion; nitrogen-rich compounds produced by chlorhexidine altered the surface morphology of the putty without crystallinity reduction. However, NaOCl reduced the organic fillers that affected its binding to phosphate ions. This reaction affects the chemical properties and perfection of root repair material. The clinicians should be aware of different irrigants to be used after repairing the perforation.

Efficacy of gaseous ozone in smoking and non-smoking gingivitis patients

BACKGROUND

The gingivitis treatment protocols aim to stop the progression of inflammation and prevent the affliction of deeper periodontal tissues. Current research focuses on novel methods that can be applied with handheld and ultrasonic devices to increase the effectiveness of non-surgical periodontal treatment. Ozone has been shown to have a strong antimicrobial effect against bacteria that play a role in the etiology of gingival/periodontal diseases. Research evaluating the effects of ozone gas on the treatment of gingival tissues is limited.

AIM

We investigated the effects of ozone application during the scaling procedure on clinical parameters of gingivitis in smokers and non-smokers and to investigate the efficacy of ozone gas in periodontal treatment.

METHODS

A total of 40 subjects, 27 males/13 females-20 smokers/20 non-smokers-with plaque-induced gingivitis, were selected. The patients underwent a single session of full-mouth supragingival and subgingival scaling. Gaseous ozone application was performed on a randomly selected maxillary quadrant. The other maxillary quadrant was designated as the control group receiving only initial periodontal treatment. Clinical parameters, such as PI, GI, GBTI, and PPD, were measured before and 1 week after treatment.

RESULTS

Our study shows that ozone therapy significantly improves clinical parameters in smokers and non-smokers when applied in addition to periodontal therapy.

CONCLUSIONS

Additional studies comparing the effect of ozone therapy on smokers and non-smokers to the effects of oral mouthwashes may provide valuable contributions to the field.

In Vitro Antimicrobial Effect of Cetylpyridinium Chloride on Complex Multispecies Subgingival Biofilm

Periodontopathogenic subgingival biofilm is the main etiological agent of periodontitis. Thus, a search for antimicrobials as adjuvant for periodontal treatment in the literature is intense. Cetylpyridinium chloride (CPC) is a well-known antimicrobial agent commonly used in mouthrinses. However, CPC effects on a complex biofilm model were not found over the literature. Therefore, the aim of this manuscript is to evaluate 0.075% CPC antimicrobial properties in a multispecies subgingival biofilm model in vitro. The subgingival biofilm composed by 31 species related to periodontitis was formed for 7 days, using the calgary device. The treatments with CPC and chlorhexidine (CHX) 0.12% (as positive control) were performed 2x/day, for 1 min, from day 3 until the end of experimental period, totaling 8 treatments. After 7 days of biofilm formation, biofilm metabolic activity was evaluated by a colorimetric reaction and biofilms microbial composition by DNA-DNA hybridization. Statistical analysis was performed using ANOVA with data transformed via BOX-COX followed by Dunnett post-hoc. Both CPC and CHX reduced biofilm metabolic activity in 60% and presented antimicrobial activity against 13 different species. Specifically, only CHX reduced levels of F.n. vicentii and P. gingivalis while only CPC reduced A. odontolyticus and A. israelli. CPC was as effective as CHX as antimicrobial through in vitro complex multispecies subgingival biofilm. However, future studies using in vivo models of experimental periodontal disease should be performed to prove such effect.

Evaluation of Plaque Removal Efficacy of Dental Floss with/without Chlorhexidine Gel Coating in Patients with Gingivitis - A Clinical and Microbological Study

BACKGROUND: Chlorhexidine has shown anti-plaque and antimicrobial effects when used as a mouthwash and appears to be effective when used as a topical antiseptic agent. AIM: The present study aimed to compare the efficacy of chlorhexidine gel coated dental floss with that of uncoated dental floss. METHODS: This parallel, single-blinded, randomized controlled clinical trial Included 30 patients with moderate to severe gingivitis. The total population was randomly divided into three groups, with ten patients in each group. Group A received dental floss with 1% chlorhexidine gel, and Group B received only dental floss, while in Group C no dental floss was provided. All thirty volunteers were provided with standard toothpaste and toothbrush. Clinical parameters such as gingival index, plaque index, and bleeding index were recorded along with supragingival plaque sample collection for microbiological culture. Subjects were recalled after 15 days and clinical and microbiological analysis was performed. All parameters were re-assessed at the follow up visit after two weeks. RESULTS: All the groups showed a significant reduction in values of plaque index, gingival index, and bleeding index, as well as the microbial counts post-enrollment in the study. A significant reduction in the bleeding indices was noticed in Group A in comparison to C (p < 0.05). CONCLUSIONS: The use of dental floss coated with 1% chlorhexidine gluconate gel was effective as an interproximal aid for patients with moderate to severe gingivitis.

Dynamics of Dissolution, Killing, and Inhibition of Dental Plaque Biofilm

The present study aims to establish a standardized model that makes it possible to evaluate the dynamic dissolution of biofilm, killing of biofilm microbes and inhibition of growth of biofilm by disinfecting solutions. Biofilm was grown from dental plaque bacteria on collagen-coated hydroxyapatite (HA) disks for 3 days or 3 weeks under anaerobic conditions. Biofilms were stained with the LIVE/DEAD viability stain and subjected to sterile water, 2% sodium hypochlorite (NaOCl), 6% NaOCl, or 2% chlorhexidine (CHX) for 32 min. Dynamic change in fluorescence on bacterial cells and extracellular polymeric substance (EPS) during the exposure was analyzed using Alexa Fluor 647-labeled dextran conjugate and a live-cell imaging confocal laser scanning microscopy (LC-CLSM). The biofilm structures after treatments were visualized by scanning electron microscopy (SEM). The treated biofilms on HA disks were collected and subjected to colony forming unit (CFU) counting. Another set of sterile HA disks were coated with CHX prior to the monitoring of plaque biofilm growth for 12 h. The LC-CLSM results showed that NaOCl dissolved biofilm effectively, more so at a higher concentration and longer exposure time. Six percent NaOCl was the most effective at dissolving and killing bacteria (e.g., 99% bacterial reduction in 3-day-old biofilm and 95% bacterial reduction in 3-week-old biofilm in 32 min) followed by 2% NaOCl and CHX. Sodium hypochlorite dissolved over 99.9% of the EPS whereas CHX only slightly reduced the EPS biovolume in 32 min. CFU results indicated that the dispersed biofilm bacteria are more resistant than planktonic bacteria to disinfectants. SEM showed the disruption of biofilm after exposures to CHX and NaOCl. The use of 2% CHX and sterile water did not result in biofilm dissolution. However, prior exposure of the HA disks to 2 and 0.2% CHX for 3 min prevented biofilm from growing on the HA disk surfaces for at least 12 h. This new platform has the potential to aid in a better understanding of the antibiofilm properties of oral disinfectants.

Vinegar inhibits the formation of oral biofilm in situ

Background

Vinegar has been recognized as an effective antimicrobial agent for long. This study intended to elucidate the effect of commercially available vinegar on in situ pellicle formation and existing 24-h biofilms.

Methods

In situ biofilm formation took place on bovine enamel slabs mounted in individual splints and exposed intraorally over 3 min and 24 h, respectively. After 5 s rinsing with vinegar, all samples were analyzed via fluorescence microscopy (FM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, salivary samples were collected and analyzed via FM. Samples with water rinsing served as controls.

Results

Vinegar caused destruction of the pellicle. Compared to the control group, vinegar rinsing reduced the outer globular layer of the pellicle (p < 0.001), and resulted in formation of subsurface pellicle. Also, vinegar rinsing could reduce bacterial viability and disrupt the 24-h biofilm. Total bacteria amount of saliva samples decreased remarkably (p < 0.001) after vinegar rinsing within 30 min. Reduction of bacterial viability was observed even 120 min after vinegar rinsing in both biofilm and saliva sample (p < 0.001).

Conclusion

This in situ study reveals that rinsing with vinegar for only 5 s alters the pellicle layer resulting in subsurface pellicle formation. Furthermore, vinegar rinsing will destruct mature (24-h) biofilms, and significantly reduce the viability of planktonic microbes in saliva, thereby decreasing biofilm formation.

Comparative Evaluation of Efficacy of Chlorhexidine and Herbal Mouthwash as a Preprocedural Rinse in Reducing Dental Aerosols: A Microbiological Study

Objective. The risk to dentists, assistants, and patients of infectious diseases through aerosols has long been recognized. The aim of this study was to evaluate and compare the efficacy of commercially available preprocedural mouth rinses containing 0.2% chlorhexidine (CHX) gluconate, Befresh™ herbal mouthwash, and water in reducing the levels of viable bacteria in aerosols. Materials & Methods. This was a single-center, double-masked, placebo-controlled, randomized, three-group parallel design study. 30 patients (10 patients in each group) were recruited in the study. Patient rinsed mouth with 10 ml of CHX, 10 ml Befresh™, or 10 ml water. All the patients underwent supragingival ultrasonic scaling for a minimum of 30 min. The aerosol collection was done using a blood agar plate. The blood agar plates were kept approximately 12 inches from the patient’s mouth. The microbial culture was analyzed. The colony-forming unit (CFU) counting in all three groups was assessed using one-way ANOVA test to compare among the groups (p value <0.001). The intergroup comparison was done using the post hoc Tukey test. Result. There was a marked reduction in the CFU in the CHX group in all three areas. This was followed by Befresh™ (Sagar Pharmaceuticals) mouthwash. There was no reduction in the CFU of the water group. Conclusion. This study proves that a regular preprocedural mouth rinse could significantly reduce the majority bacteria present in aerosols generated by the use of an ultrasonic unit, and Befresh™ mouth rinse was found to be equally effective in reducing the aerosol contamination to 0.2% CHX gluconate.

Antibacterial action of nitric oxide-releasing hyperbranched polymers against ex vivo dental biofilms

OBJECTIVES

This study investigates the antibiofilm action of nitric oxide (NO)-releasing hyperbranched polymers against ex vivo multispecies periodontal biofilms.

METHODS

The antibiofilm efficacy of NO-releasing hyperbranched polymers was evaluated as a function of NO-release properties, polymer concentrations, and oxygen levels in the exposure media. 16s rRNA sequencing technique was employed to evaluate the impact of NO-releasing hyperbranched polymers on the microbial composition of the biofilms.

RESULTS

The addition of NO release significantly improved the antibiofilm action of the hyperbranched polymers, with NO-releasing hyperbranched polyamidoamines of largest NO payloads being more effective than hyperbranched polykanamycins. Furthermore, the NO-releasing hyperbranched polymers reduced the biofilm metabolic activity in a dose-dependent manner, killing biofilm-detached bacteria under both aerobic and anaerobic conditions, with greater antimicrobial efficacy observed under aerobic conditions.

SIGNIFICANCE

These results demonstrate for the first time the potential therapeutic utility of NO-releasing hyperbranched polymers for treating multispecies dental biofilms.

Tea Tree Oil versus Chlorhexidine Mouthwash in Treatment of Gingivitis: A Pilot Randomized, Double Blinded Clinical Trial

Objective  The study evaluated the efficacy of tea tree oil for the treatment of gingivitis.

Materials and Methods  The tea tree oil was administered in the form of mouthwash and then compared with a mouthwash with chlorhexidine 0.12%. Both treatments were domestic and lasted for 14 days. Patients were chosen according to random criteria, aged between 18 and 60 years, and who showed a clinically evident gingivitis. In clinical evaluation, the following clinical criteria were taken into consideration: gingival index (GI), plaque index (PI), bleeding index (BI), probing depth (PD), the presence of dental dyschromia, and the presence of taste alteration. The subjects were evaluated before (T0) and after the treatment (T1), and the data collected for each patient were recorded on a periodontal chart.

Results  The comparison showed that tea tree oil offered a better improvement in the evaluation of PI, BOP, and PD; furthermore, it did not cause dental dyschromia and taste alteration. In group A, treated with tea tree oil, PI decreased from 53.25 to 5.50% and BI from 38.41 to 4.22%. In group B, treated with chlorhexidine PI decreased from 47.69 to 2.37% and BI from 32.93 to 6.28%. Instead, the subjects using chlorhexidine 0.12% blamed a distaste for the product that caused a slight taste alteration; 20% of them showed iatrogenic dental dyschromia.

Conclusions  The collected data showed the efficacy of both treatments. Although further research works will be necessary, this study showed that tea tree oil could be an effective nontoxic substitute for the therapy of gingivitis.

Oral rinses in growth inhibition and treatment of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) is well-known for its role in chronic gastritis and gastric cancer. Eradication of these carcinogenic bacteria from the gut is one of the challenges for clinicians. The complexity of treatment mainly owes to antibiotic resistance and relapse due to an additional reservoir in the oral cavity. Our study emphases the isolation of H. pylori from distinct habitats of the gut microenvironment (gastric biopsy and gastric juice) and its subsequent characterization. We have also evaluated the effect of various oral rinses on isolated H. pylori from different anatomical locations of included subjects.

RESULTS

The possible strains isolated from two different habitats of the same subject shows a striking difference in their growth pattern. Promisingly, some of the included oral rinses are efficient in growth inhibition as per recommended 30 s treatment. The subsequent evaluation shows that oral rinse B (among A-E) is most effective and down-regulates the expression of one of the potent H. pylori gene, CagA, in the infected gastric adenocarcinoma (AGS) cells.

CONCLUSION

Our study, for the first time, revealed that H. pylori, isolated from the different habitat of the same subject, show a different growth pattern. The expression of H. pylori pathogenic gene (CagA) was down-regulated by the use of oral rinses. Hence, oral rinses will reduce the H. pylori in the oral cavity and help to control its migration from oral to the gastric compartment and may be used as an adjuvant treatment option for its re-infection.

Comparative evaluation of the effect of curcumin and chlorhexidine on human fibroblast viability and migration: An in vitro study

Background and Objective:

Chemical plaque control acts as an adjunct to mechanical periodontal therapy. Chlorhexidine (CHX) is considered as the gold standard in chemical plaque control, but the main concern is about its fibroblast cytotoxicity. Curcumin, a lipophilic polyphenol, may offer as a promising antiplaque agent. This study was conducted to compare the effect of curcumin (0.003%, 0.03%, 0.06%, 0.1%, and 0.12%) and CHX (0.03%, 0.06%, 0.1%, 0.12%, and 0.2%) on gingival fibroblast cell viability and wound healing at different time periods (1, 2, 4, 6, 8, and 10 min).

Materials and Methods:

The minimum inhibitory concentration (MIC50) was determined before the evaluation of cytotoxicity and wound healing property. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and morphological examination by direct invert microscopy were carried out to determine cytotoxicity. Wound healing was evaluated by scratch wound assay.

Results and Discussion:

The MIC50 of CHX and curcumin was at 0.1% and 0.003%, respectively. The mean percentage of fibroblast viability at different concentrations of CHX and curcumin at each time period showed a significant difference. Curcumin exhibited less cytotoxicity as compared to CHX at all concentrations and at varying time periods. There was a significant difference between mean percentage of fibroblast viability at MIC50 of CHX (0.1%) and curcumin (0.003%) at different time periods. The difference between percentage wound healing at antibacterial concentrations of CHX and curcumin at varying time periods was significant.

Conclusion:

The antibacterial concentration of curcumin (0.003%) exhibits less fibroblast cytotoxicity and excellent wound healing property as compared to CHX. Curcumin may offer as a promising chemical plaque control agent which is less cytotoxic, cost-effective, safe, easily available, and with a possibly beneficial effect on wound healing.

Oral biofilm elimination by combining iron-based nanozymes and hydrogen peroxide-producing bacteria

Dental caries is a global risk in terms of oral health in many schoolchildren and in a vast majority of adults. The primary factor for caries formation is the attachment of bacteria on the tooth surface to form an oral biofilm which generates acids to demineralize calcium and eventually cause tooth decay. Oral biofilm elimination is still a challenge because bacteria are embedded inside with the biofilm matrix protecting them, preventing the penetration of antibiotics or bactericides. Promising strategies for disrupting oral biofilms have been developed, including the use of natural enzymes to degrade the biofilm matrix and hydrogen peroxide to kill bacteria. Here we demonstrate a strategy that combines nanozymes with peroxidase-like activity and bacteria generating biogenic hydrogen peroxide to eliminate oral biofilms for caries treatment. By using a saliva-coated hydroxyapatite disc and sectioned human tooth to mimic the real oral environment, we analyze the influence of iron oxide nanozymes or iron sulfide nanozymes on a Streptococcus mutans biofilm in the presence of Streptococcus gordonii which can generate hydrogen peroxide. Bacterial viability assays and biofilm morphology characterization show that the combination of nanozymes and bacteria remarkably reduces the bacteria number (5 lg reduction) and biofilm matrix (85% reduction). Therefore, the combination of iron-based nanozymes and hydrogen peroxide-generating bacteria may provide a new strategy for oral biofilm elimination in dental caries treatment.

Effects of a sub-minimum inhibitory concentration of chlorhexidine gluconate on the development of in vitro multi-species biofilms

Following antimicrobial administrations in oral environments, bacteria become exposed to a sub-minimum inhibitory concentration (sub-MIC), which can induce in vitro single-species biofilms. This study explored the effects of chlorhexidine gluconate (CHG) at a sub-MIC on in vitro multi-species biofilms comprising Streptococcus mutans, Streptococcus oralis and Actinomyces naeslundii. CHG at a sub-MIC was found to induce in vitro biofilm growth, although the bacterial growth was not significantly different from that in the control. The gene transcription related to S. mutans multi-species biofilm formation with CHG at a sub-MIC was significantly higher than that of the control, but this was not found in S. mutans single-species biofilms. The bio-volume of extracellular polysaccharides with CHG at a sub-MIC was significantly higher than that of the control. This suggests that CHG at a sub-MIC may promote the development of multi-species biofilms by affecting the gene transcription related to S. mutans biofilm formation.

Effects of Herbal Mouthwashes on Plaque and Inflammation Control for Patients with Gingivitis: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Objective

The aim of this study was to evaluate the overall effects of herbal mouthwashes as supplements to daily oral hygiene on plaque and inflammation control compared with placebos and chlorhexidine (CHX) mouthwashes in the treatment of gingivitis.

Methods

PubMed, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and grey literature databases were searched. Only randomised controlled trials (RCTs) comparing herbal mouthwashes with placebos or CHX in the daily oral hygiene of patient with gingivitis were included to compare the effect of different mouthwashes on plaque and inflammation control.

Results

A total of 13 studies satisfied the eligibility criteria, and 11 studies were included in meta-analyses. Significant differences were observed in favour of herbal mouthwashes compared with placebos in both plaque- and inflammation-related indices (Quigley-Hein Plaque Index, QHPI: WMD = −0.61, 95% CI (−0.80, −0.42), P < 0.001; Gingival Index, GI: −0.28 (−0.51, −0.06), P=0.01; Modified Gingival Index, MGI: −0.59 (−1.08, −0.11), P=0.02; Gingival Bleeding Index, GBI: −0.06 (−0.09, −0.04), P < 0.001). No significant difference was found between herbal and CHX mouthwashes.

Conclusions

Herbal mouthwashes have potential benefits in plaque and inflammation control as supplements to the daily oral hygiene of patients with gingivitis. Although no difference was observed between herbal and CHX mouthwashes in the selected studies, further high-quality RCTs are needed for more firm support before advising patients with gingivitis about whether they can use herbal mouthwashes to substitute for CHX mouthwashes or not (PROSPERO registration number: CRD42019122841).

The effects of cavity disinfection on the nanoleakage of compomer restorations: an in vitro study

Purpose:

Cavity disinfection, in addition to routine caries removal methods, is recommended to eliminate the microorganisms. The aim of this study was to compare the effect of various systems Er,Cr:YSGG lasers, diode lasers and FotoSan and agents Corsodyl; Cervitec and Cervitec Plus and Fluor Protector—on the nanoleakage of compomer restorations when used for cavity disinfection.

Materials and methods:

A total of 40 intact human deciduous molar teeth containing Black V cavities (3×2×1.5 mm) on the buccal and lingual surfaces parallel to the cementoenamel junction were randomly divided into 8 groups according to the cavity disinfection methods. The antibacterial agents and systems were applied according to the manufacturer’s instructions. Restorations were completed using a compomer. The restored teeth were then subjected to thermocycling for 500 cycles in a water bath at 5°C and 55°C with a dwell time of 30 seconds. After the thermocycling procedures, 1-mm sticks were obtained from the center of each cavity to prepare for the nanoleakage test. After the teeth were sectioned, they were immersed in 50 wt % ammoniacal silver nitrate solution for 24 hours and dipped in photo-developing solutions for 8 hours with fluorescent light irradiation. The samples were examined under a scanning electron microscope (SEM). The non-parametric Kruskal-Wallis and Mann-Whitney U test (p<0.05) were applied.

Results:

The Er,Cr:YSGG laser group showed significantly less nanoleakage than all of the tested groups (p<0.01). The diode laser, Fluor protector and FotoSan groups showed similar nanoleakage to that of the control group (p>0.05). The Corsodyl (p<0.01) and Cervitec (p<0.001) groups showed significantly higher nanoleakage than the control group.

Conclusion:

Er,Cr:YSGG laser irradiation which showed lower nanoleakage scores from either control or tested groups can be recommended for cavity disinfection Additionally, a diode laser and FotoSan, which have antibacterial effects and no negative effect on leakage, can be used for cavity disinfection.

Effects of Chlorine Dioxide on Oral Hygiene - A Systematic Review and Meta-analysis

BACKGROUND

Effective and selective oral rinses are required in the daily medical and dental practice. Currently mouthwashes used have substantial side effects.

OBJECTIVES

Our aim was to evaluate the efficacy of chlorine dioxide-containing mouthwashes in comparison with other previously established mouth rinses in healthy adults using oral hygiene indices.

METHODS

This work was registered in PROSPERO (CRD42018099059) and carried out using multiple databases and reported according to the PRISMA statement. The search terms used were "chlorine dioxide" AND "oral", and only randomised controlled trials (RCTs) were included. The primary outcome was the alteration of the plaque index (PI), while the secondary outcomes were the gingival index (GI) and bacterial counts. For the risk of bias assessment, the Cochrane Risk of Bias Tool was used. Statistical analysis for data heterogeneity was performed by Q-value and I2-tests.

RESULTS

364 articles were found in the databases. After the selection process, only five RCTs were eligible for meta-analysis. Data heterogeneity was low. There were no statistical differences in effectiveness between chlorine dioxide and other effective mouth rinses in PI (0.720±0.119 vs 0.745±0.131; 95%; confidence intervals (CIs): 0.487-0.952 vs 0.489-1.001, respectively) and GI (0.712±0.130 vs 0.745±0.131; 95% CIs: 0.457-0.967 vs 0.489- 1.001, respectively) and also in bacterial counts.

CONCLUSION

Chlorine dioxide reduces both plaque and gingival indices and bacterial counts in the oral cavity similar to other routinely used oral rinses, however, the evidence supporting this outcome is very limited. Therefore, further large scale RCTs are needed to decrease the risk of bias.

Antibacterial Activity of Chlorhexidine-Killed Bacteria: The Zombie Cell Effect

We report a biocidal zombie effect of chlorhexidine, a wide-scope biocidal agent commonly used in disinfectant and antiseptic formulations. The zombie effect refers to the ability of dead bacteria killed by a biocidal agent to act as efficient biocidal agents toward a new generation of viable bacteria. The killed bacteria serve as a reservoir for the antibacterial agent incorporated within them; and the new viable population of bacteria acts as a trap of the bioactive agent, shifting the equilibrium of this agent between the reservoir in the dead cells and their aqueous environment. This report is a major generalization of the zombie phenomenon reported previously for silver from the points of view of extending to organic antibacterial agents; extending the effect to both Gram-negative-Pseudomonas aeruginosa PAO1-and Gram positive-Staphylococcus aureus-representative bacteria; showing that the zombie effect is maintained in the second and third generations; showing the effect to operate in an environment of growth media, which extends it to life-supporting environments; and proving that cross-killing is possible, that is, killed S. aureus cells fully inactivated viable P. aeruginosa.

Effects of S. mutans gene-modification and antibacterial monomer dimethylaminohexadecyl methacrylate on biofilm growth and acid production

OBJECTIVES

Antibacterial quaternary ammonium monomers (QAMs) are used in resins. The rnc gene in Streptococcus mutans (S. mutans) plays a key role in resisting antibiotics. The objectives of this study were to investigate for the first time: (1) the effects of rnc deletion on S. mutans biofilms and acid production; (2) the combined effects of rnc deletion with dimethylaminohexadecyl methacrylate (DMAHDM) on biofilm-inhibition efficacy.

METHODS

Parent S. mutans strain UA159 (ATCC 700610) and the rnc-deleted S. mutans were used. Bacterial growth, minimum inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) were measured to analyze the bacterial susceptibility of the parent and rnc-deleted S. mutans against DMAHDM, with the gold-standard chlorhexidine (CHX) as control. Biofilm biomass, polysaccharide and lactic acid production were measured.

RESULTS

The drug-susceptibility of the rnc-deleted S. mutans to DMAHDM or CHX was 2-fold higher than parent S. mutans. The drug-susceptibility did not increase after 10 passages (p < 0.05). Deleting the rnc gene increased the biofilm susceptibility to DMAHDM or CHX by 2-fold. The rnc-deletion in S. mutans reduced biofilm biomass, polysaccharide and lactic acid production, even at no drugs. DMAHDM was nearly 40 % more potent than the gold-standard CHX. The combination of rnc deletion+DMAHDM treatment achieved the greatest reduction in biofilm biomass, polysaccharide synthesis, and lactic acid production.

SIGNIFICANCE

Gene modification by deleting the rnc in S. mutans reduced the biofilm growth and acid production, and the rnc deletion+DMAHDM method showed the greatest biofilm-inhibition efficacy, for the first time. The dual strategy of antibacterial monomer+bacterial gene modification shows great potential to control biofilms and inhibit caries.

Determination of chlorhexidine retention in different oral sites using matrix-assisted laser desorption/ionization-time of flight mass spectrometry

OBJECTIVE

The aim of this study was to determine chlorhexidine retention in different oral sites after a one-time 30 s mouth rinsing.

DESIGN

Five volunteers were asked to rinse their mouth with 10 ml of 0.2 % chlorhexidine digluconate for 30 s. After rinsing, samples were collected from the interdental area, buccal dental pellicle, anterior labial and posterior buccal mucosa, and saliva with a microbrush at five-time points within 24 h. Retention of chlorhexidine was measured using matrix-assisted laser desorption/ionization-time of flight mass spectrometry with a quantification limit of 15 ng/ml.

RESULTS

Chlorhexidine remained in the oral cavity at micrograms per milliliter levels for 11 h after mouth rinsing and was even detected 24 h after application. The results showed a distinct decline of intraoral chlorhexidine levels during the first 6 h after rinsing and it was then retained at low concentrations for at least 24 h.

CONCLUSIONS

The dental pellicle and oral mucosa were favorable sites for chlorhexidine retention. The novel method used for chlorhexidine determination offered excellent quantification limits and readily permitted quantification of chlorhexidine.

Tolerability of a green tea-based mouth rinse: A pilot study

Introduction

Mouth rinse containing essential oil is one of the most popular, over the counter dental products which has been promoted to have anti-inflammatory, anti-plaque and anti-microbial properties. An essential oil alcohol-free mouth rinse with green tea has been introduced recently and promoted for management of periodontitis and gingivitis. As the role of chlorhexidine gluconate (CHX) mouth rinse in management of periodontal disease has been evaluated previously, the aim of this study is to compare the tolerability of none-alcohol containing green tea-based (NAGT) mouth rinse with CHX mouth rinse.

Methods

Forty healthy subjects were enrolled in September 2018 at King Abdulaziz University and allocated randomly to two study arms: NAGT mouth rinse and chlorhexidine gluconate mouth rinse. Study subjects were instructed to follow the manufacturer instructions and rinse twice daily for two weeks. Collected data included age, gender, smoking history in addition to subjective assessment using a validated questionnaire. Intraoral clinical examination was completed at baseline and 2-weeks time point.

Results

The data of 36 patients were included in this study and analyzed. At 2 weeks, NAGT group reported higher burning sensation score compared to chlorhexidine group (mean: 4.33 and 0.6 respectively; P < 0.05). Reported mucosal dryness was more evident in NAGT group (mean: 1.9 Vs 1.7 for chlorhexidine group). Oral examination revealed significant mucosal desquamation (27.8%) in NAGT group. However, oral ulceration was reported equally in both groups (5.6%).

Conclusion

The current data demonstrates an overall less tolerability of a non-alcohol containing green tea-based mouth rinse compared to chlorhexidine gluconate. Further long term randomized clinical trials are recommended to confirm our findings.

Evidence-based strategy for dental biofilms: Current evidence of mouthwashes on dental biofilm and gingivitis

Therapeutic mouthwash (MW) is an adjunctive tool along with a regular oral hygiene routine of daily tooth brushing and daily flossing. Previous systematic reviews have demonstrated that it is effective against dental biofilm and gingival inflammation, for prevention of dental caries, and for managing one's bad breath condition according to the active ingredients. MWs prevent the microorganisms from bacterial adhesion that corresponds to the initial step in biofilm formation. This review summarized the current state of evidence such as anti-biofilm, anti-gingivitis and cariostatic properties of MWs by evaluating systematic reviews from the past six years. The anti-biofilm property has been proven to be effective, with strong evidence of three main clinical efficacies. The most commonly studied active agent was chlorhexidine gluconate (CHX), followed by essential oil (EO) and cetylpyridinium chloride. All the systematic reviews are in complete agreement that CHX and EO provide statistically significant improvements in terms of plaque and gingival indices. These effects have held up over the years as the number of studies has increased. While the use of fluoride MW is proven to be effective in improving the oral health of both children and adults, the quality of evidence is still regarded as low.

Antimicrobial and antibiofilm effects of abietic acid on cariogenic Streptococcus mutans

Dental caries is a type of oral microbiome dysbiosis and biofilm infection that affects oral and systemic conditions. For healthy life expectancy, natural bacteriostatic products are ideal for daily and lifetime use as anti-oral infection agents. This study aimed to evaluate the inhibitory effects of abietic acid, a diterpene derived from pine rosin, on the in vitro growth of cariogenic bacterial species, Streptococcus mutans. The effective minimum inhibitory concentration of abietic acid was determined through observation of S. mutans growth, acidification, and biofilm formation. The inhibitory effects of abietic acid on the bacterial membrane were investigated through the use of in situ viability analysis and scanning electron microscopic analysis. Cytotoxicity of abietic acid was also examined in the context of several human cell lines using tetrazolium reduction assay. Abietic acid was found to inhibit key bacterial growth hallmarks such as colony forming ability, adenosine triphosphate activity (both planktonic and biofilm), acid production, and biofilm formation. Abietic acid was identified as bacteriostatic, and this compound caused minimal damage to the bacterial membrane. This action was different from that of povidone-iodine or cetylpyridinium chloride. Additionally, abietic acid was significantly less cytotoxic compared to povidone-iodine, and it exerted lower toxicity towards epithelial cells and fibroblasts compared to that against monocytic cells. These data suggest that abietic acid may prove useful as an antibacterial and antibiofilm agent for controlling S. mutans infection.

Does antimicrobial coating and impregnation of urinary catheters prevent catheter-associated urinary tract infection? A review of clinical and preclinical studies

Introduction: Catheter-associated urinary tract infection (CAUTI) is one of the most common nosocomial infections in hospitals, accounting for 36% of all health care-associated infections. Areas covered: We aimed to address the potential impact of antimicrobial coating of catheter materials for the prevention of CAUTI and to analyze the progress made in this field. We conducted literature searches in the PubMed, Embase, and Cochrane Library databases, and found 578 articles. Data from 60 articles in either the preclinical or clinical stage were analyzed in this expert review. Expert opinion: The literature review revealed many promising methods for preventing CAUTI. Recent studies have suggested the combination of silver-based products and antibiotics, owing to their synergistic effect, to help address the problem of antibiotic resistance. Other coating materials that have been tested include nitric oxide, chlorhexidine, antimicrobial peptides, enzymes, and bacteriophages. Because of heterogeneity among studies, it is difficult to reliably comment on the clinical efficacy of different coating materials. Future research should focus on double-blind randomized clinical trials for evaluating the role of these potential coating agents.

The impact of 0.2% chlorhexidine gel on oral health and the incidence of pneumonia amongst adults with profound complex neurodisability

AIMS

Investigate the effect of toothbrushing with 0.2% chlorhexidine gel on oral health and pneumonia amongst patients with a neurodisability who are fed via percutaneous endoscopic gastrostomy.

METHOD

Forty-nine patients at the Royal Hospital for Neuro-disability were recruited to an observational study. Daily toothbrushing with 0.2% chlorhexidine gel was undertaken for 12 months by trained nursing staff. Plaque and gingival health were assessed every six weeks using the Simplified Debris Index and the Basic Periodontal Examination. The annual incidence and prevalence of episodes of pneumonia experienced by patients whilst using the chlorhexidine gel were compared to rates from the previous year.

RESULTS

Plaque levels and the proportion of patients with periodontal pocketing > 3.5 mm significantly reduced, P < .001, with chlorhexidine toothbrushing. Total number of pneumonia episodes (75-67), antibiotics administered (73-64), and radiographs taken (19 to 16) were lower in the year wherein chlorhexidine was employed, and hospitalisations dropped by 31% (16-11), but these reductions were not statistically significant. No adverse events were reported.

CONCLUSION

Daily toothbrushing with 0.2% chlorhexidine undertaken by a trained and supported nursing staff was effective in improving oral health but did not significantly affect annual rates of pneumonia amongst patients.

A Critical Review of Modern Concepts for Teeth Whitening

Besides prevention of caries and periodontitis, an increasing number of oral care products focus on teeth whitening. The aim of this review is to summarize and discuss frequently used whitening agents and their efficacy from a chemical viewpoint. Therefore, a comprehensive literature survey on teeth whitening agents and products was conducted. The current whitening methods are analyzed and discussed from a chemist’s viewpoint. Frequently used whitening agents are abrasives (mechanical removal of stains), antiredeposition agents (prevention of deposition of chromophores), colorants (intended to lead to a white color), proteases (degradation of proteins), peroxides (oxidation of organic chromophores), and surfactants (removal of hydrophobic compounds from tooth surface). In-office bleaching using peroxides is effective, but side effects like tooth sensitivity or a damage of the natural organic matrix of enamel and dentin may occur. The applicability of abrasives in teeth whitening is limited due to potential tooth wear, especially when toothpastes with high RDA values are used. The effect of other whitening agents in vivo is often unclear because of a shortage of placebo-controlled clinical trials.

Evaluation of Herbal Mouthwashes Containing Zataria Multiflora Boiss, Frankincense and Combination Therapy on Patients with Gingivitis: A Double-Blind, Randomized, Controlled, Clinical Trial

Background

Dental plaques as adhesive microbial aggregates on tooth surfaces are considered the first stage of tooth decay as well as gingivitis. Accordingly, the effect of different antimicrobial mouthwashes on removing dental plaques and preventing their formation has been evaluated in various studies. This study aimed to evaluate the efficacy of herbal mouthwashes containing hydro-alcoholic extract of Zataria multiflora (ZM), Frankincense (FR), and a combination of both (ZM+FR) and compare it with chlorhexidine (CHX) mouthwash in subjects with gingivitis.

Materials and Methods

In this randomized, controlled, clinical trial a total of 140 patients with gingivitis were divided into four groups including CHX (control group), ZM, FR, and ZM+FR groups. Plaque index (PI), gingival index (GI), and gingival bleeding index (GBI) were measured in days 1, 14, and 21.

Results

All three herbal types of mouthwash significantly improved plaque, gingivitis, and gingival bleeding throughout days 14 to 21 (P<0.001). There was no difference between herbal mouthwash with CHX groups. CHX mouthwash showed the most side effects (54.3%), while ZM mouthwash showed the least side effects and the highest consumer satisfaction (5.7% and 94%, respectively).

Conclusion

All of the herbal mouthwashes can be good candidates for controlling gingivitis. Comparing with CHX mouthwash, herbal mouthwashes have lower side effects and negligible alcohol content. Among the herbal mouthwashes, ZM outperforms FR and FR+ZM due to its lower side effects and higher levels of patients' satisfaction.

Back to Basics: Could the Preoperative Skin Antiseptic Agent Help Prevent Biofilm-Related Capsular Contracture?

BACKGROUND

Capsular contracture (CC) has remained an unresolved issue throughout history. Strong evidence focuses on bacterial biofilm as its main source. A literature review revealed that more than 90% of bacteria found in capsules and implants removed from patients with Baker grade III-IV CC belong to the resident skin microbiome (Staphylococcus epidermidis, predominant microorganism). The use of an adequate preoperative skin antiseptic may be a critical step to minimize implant contamination and help prevent biofilm-related CC.

OBJECTIVES

The authors sought to compare the effect of 2 different antiseptic skin preparations: povidone-iodine (PVP-I) vs chlorhexidine gluconate (CHG) on CC proportions after primary breast augmentation through a periareolar approach.

METHODS

In June of 2014, The Society for Healthcare Epidemiology of America proposed to use CHG for preoperative skin preparation in the absence of alcohol-containing antiseptic agents as strategy to prevent surgical site infection. The clinical safety committee of a surgical center in Colombia decided to change PVP-I to CHG for surgical site preparation thereafter. The medical records of 63 patients who underwent to primary breast augmentation through a periareolar approach during 2014 were reviewed. In the first 6 months PVP-I was used in 32 patients, and later CHG was employed in 31 patients.

RESULTS

Pearson's chi-squared test to compare CC proportions between subgroups showed a statistically significant difference. The CC proportion was higher for patients who had antisepsis with PVP-I. CC was absent when CHG was employed.

CONCLUSIONS

CHG as preoperative skin antiseptic for primary breast augmentation surgery was more effective than PVP-I to help prevent biofilm-related CC.

LEVEL OF EVIDENCE: 3

Effectiveness of Different Commercial Chlorhexidine-Based Mouthwashes After Periodontal and Implant Surgery: A Systematic Review

OBJECTIVES

The aim of the present study was to review the effectiveness, side effects, and patient acceptance of different concentrations and formulation of chlorhexidine-based mouthwashes used after periodontal and implant surgery.

MATERIALS AND METHODS

The PRISMA guideline was adopted in the search strategy using electronic databases PubMed and MEDLINE to identify randomized and case-control prospective studies on humans written in English language and published up to September 2017.

RESULTS

A total of 10 articles were selected for a total of 344 patients. Because of the significant heterogeneity of the outcome measures, meta-analysis was not performed, and the data were summarized in a table. A positive relationship between the use of chlorhexidine and reduction of plaque was found, demonstrating the effectiveness of the substance in terms of antisepsis and decrease of inflammation after periodontal and implant surgery.

CONCLUSION

Chlorhexidine is recognized as the primary agent for plaque control and the gold standard in preventing infection, although the presence of largely known side effects would affect patient compliance. Future research should be directed at finding chlorhexidine formulation with negligible adverse effects, without compromising or even increasing its effectiveness as the antiseptics and antiplaque agent.

Matrix metalloproteinases and inhibitors in dentistry

OBJECTIVES

Matrix metalloproteinase (MMP) expression has been associated with tissue development, invasive cancer cell behavior, and inflammation. The associations of increased expression of MMPs with diseases have led to intensive research activities to develop MMP inhibitors. Here, the questions are addressed which associations between increased levels of any MMP with dental diseases may be cause or consequence, whether MMP levels may be of diagnostic value and whether and which MMP inhibitors need further investigations for use in dental diseases.

METHODS

To study the role of MMPs and to discriminate between cause or consequence, the literature about measurements of MMPs and about the use of inhibitory drugs and genetic knockout animal models in dentistry was compared.

RESULTS

The only FDA-approved treatment with MMP inhibitors is tetracyclines for periodontitis, whereas a diagnostic test for activated MMP-8 in oral fluids is valued in practical periodontology. The MMP literature in dentistry is artificially skewed to the gelatinases MMP-2 and MMP-9 and to enamelysin, alias MMP-20. The basis for this observation is, respectively, the widely used and sensitive technique of gelatin zymography and enamel proteins as substrates of MMP-20. Studies on additional MMPs are gaining interest in dentistry and MMP inhibitors may provide new applications. In addition, drugs with proven effects for the treatment of dental diseases may be found to act through MMP inhibition.

CONCLUSION AND RELEVANCE

In conclusion, research on MMPs and inhibitors may provide practical applications beyond diagnosis and treatment of periodontitis and will be, directly or indirectly, beneficial for patients with dental or periodontal diseases.

Hydroxyapatite in Oral Biofilm Management

Particulate hydroxyapatite, Ca5 (PO4)3 (OH), shows a good biocompatibility and is used as a biomimetic ingredient in dental care formulations due to its similarity to human enamel. Numerous studies show its efficiency, for example, in reducing dentin hypersensitivity, and in the remineralization of enamel and dentin. In addition, oral care products with hydroxyapatite improve periodontal health under in vivo conditions. This review article summarizes data on the effects of hydroxyapatite particles in oral biofilm management. Two databases (PubMed and SciFinder) were searched for studies using specific search terms. In contrast to frequently used antibacterial agents for biofilm control, such as chlorhexidine, stannous salts, and quaternary ammonium salts, hydroxyapatite particles in oral care products lead to a reduction in bacterial attachment to enamel surfaces in situ without having pronounced antibacterial effects or showing unwanted side effects such as tooth discoloration. Furthermore, antibacterial agents might lead to dysbiosis of the oral ecology, which was recently discussed regarding pros and cons. Remarkably, the antiadherent properties of hydroxyapatite particles are comparable to those of the gold standard in the field of oral care biofilm management, chlorhexidine in situ. Although biomimetic strategies have been less well analyzed compared with commonly used antibacterial agents in oral biofilm control, hydroxyapatite particles are a promising biomimetic alternative or supplement for oral biofilm management.

Comparative evaluation of Chlorhexidine, Metronidazole and combination gels on gingivitis: A randomized clinical trial

Introduction

Dental plaque has been established as an etiological factor in the development of gingivitis and periodontitis. Several antimicrobials including Chlorhexidine and Metronidazole have been used as an adjuvant to mechanical plaque removal.

Objective

To compare 0.8% Metronidazole gel, 0.2% Chlorhexidine gel and alternate application of the two gels in reducing gingival inflammation when used for 14 days as an adjuvant with home based oral hygiene instructions.

Methods

The bleeding sites, probing depth and the gingival index score will be calculated. (Group A standard 0.2% Chlorhexidine gel applied on the marginal gingiva; Group B subjects will be instructed to apply 0.8% Metronidazole gel; Group C subjects 0.2% Chlorhexidine gel on the marginal gingiva after morning tooth brushing and 0.8% Metronidazole gel after evening tooth brushing). After 2 weeks second clinical examination will be carried out for bleeding sites, probing depth and the gingival index score. Scaling & polishing of teeth in all three groups and oral hygiene instructions will be reinforced. Subjects will be recalled at 6 weeks for evaluation of gingival and oral hygiene indices. Descriptive statistics for variables such as age, baseline clinical parameters including probing depth, bleeding sites, gingival index, and oral hygiene index will be computed. Generalized estimation equation (GEE) will be run to account for the correlated data for the comparison of study arms. Friedman test will be used to assess the bleeding sites among three study groups at the baseline and endpoint. Similarly, gingival index and oral hygiene index in the three groups at baseline, after 2 weeks and 4 weeks will be compared. The level of significance will be kept at 0.05.

Resistance Toward Chlorhexidine in Oral Bacteria - Is There Cause for Concern?

The threat of antibiotic resistance has attracted strong interest during the last two decades, thus stimulating stewardship programs and research on alternative antimicrobial therapies. Conversely, much less attention has been given to the directly related problem of resistance toward antiseptics and biocides. While bacterial resistances toward triclosan or quaternary ammonium compounds have been considered in this context, the bis-biguanide chlorhexidine (CHX) has been put into focus only very recently when its use was associated with emergence of stable resistance to the last-resort antibiotic colistin. The antimicrobial effect of CHX is based on damaging the bacterial cytoplasmic membrane and subsequent leakage of cytoplasmic material. Consequently, mechanisms conferring resistance toward CHX include multidrug efflux pumps and cell membrane changes. For instance, in staphylococci it has been shown that plasmid-borne qac ("quaternary ammonium compound") genes encode Qac efflux proteins that recognize cationic antiseptics as substrates. In Pseudomonas stutzeri, changes in the outer membrane protein and lipopolysaccharide profiles have been implicated in CHX resistance. However, little is known about the risk of resistance toward CHX in oral bacteria and potential mechanisms conferring this resistance or even cross-resistances toward antibiotics. Interestingly, there is also little awareness about the risk of CHX resistance in the dental community even though CHX has been widely used in dental practice as the gold-standard antiseptic for more than 40 years and is also included in a wide range of oral care consumer products. This review provides an overview of general resistance mechanisms toward CHX and the evidence for CHX resistance in oral bacteria. Furthermore, this work aims to raise awareness among the dental community about the risk of resistance toward CHX and accompanying cross-resistance to antibiotics. We propose new research directions related to the effects of CHX on bacteria in oral biofilms.

Characteristics of an alternative antibacterial biomaterial for mouthwash in the absence of alcohol

Background/purpose

The purpose of this study was to investigate whether poly-gamma-glutamic acid (γ-PGA), a naturally derived biomaterial, was suitable as an alternative antibacterial mouthwash in the absence of alcohol.

Materials and methods

Three bacterial strains, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, were used for testing the antibacterial activity of mouthwashes. In addition, cell viability, cytotoxicity, and genotoxicity experiments were conducted for testing the toxicity of mouthwashes.

Results

We demonstrated that 10000 ppm of γ-PGA without alcohol could efficiently inhibit 99% of bacterial growth. In addition, γ-PGA did not cause any cytotoxicity or genotoxicity.

Conclusion

10000 ppm of γ-PGA in an alcohol-free mouthwash is an alternative biomaterial for mouthwashes.

Effect of Propolis mouthwash on plaque and gingival indices over fixed orthodontic patients

Background

In patients with fixed orthodontics, the presence of orthodontic appliances causes dental plaque accumulation and hygiene problems. The purpose of this study was to evaluate the effect of Propolis and chlorhexidine mouthwashes on plaque and gingival indices in patients who are undergoing orthodontic treatment.

Material and Methods

In this triple blind study, in total, 37 patients aged from 15 to 35 years those who have been undergoing fixed orthodontic treatment were studied. After that, one of the mouthwashes that containing either Propolis or Chlorhexidine was randomly prescribed to patients. The patients were asked to use mouthwashes twice a day after brushing their teeth for three weeks consecutively. Indicators of plaque, gingival and periodontal status (PI, GI, CPI) were determined on Ramford teeth at the beginning and at the end of three weeks for each patient. Then the results were analyzed statistically.

Results

The difference between the values of plaque index (P<0.001), gingival index (P=0.006) and periodontal index (P= 0.005) before and after administration of Propolis were statistically significant. The difference was also statistically significant for all three indexes of plaque (P<0.001), gingival (P=0.001) and periodontal (P=0.003) before and after chlorhexidine mouthwash usage. The indices after using mouthwashes were not statistically significant different between two mouthwash groups.

Conclusions

It seems that Propolis mouthwash can be used as a suitable alternative in patients with fixed orthodontic treatment without the side effects of chlorhexidine mouthwash.

Key words:Mouthwash, antimicrobial, Oral hygiene, Propolis, Dental plaque.

Evaluation of short exposure times of antimicrobial wound solutions against microbial biofilms: from in vitro to in vivo

Objectives

Test the performance of topical antimicrobial wound solutions against microbial biofilms using in vitro, ex vivo and in vivo model systems at clinically relevant exposure times.

Methods

Topical antimicrobial wound solutions were tested under three different conditions: (in vitro) 4% w/v Melaleuca oil, polyhexamethylene biguanide, chlorhexidine, povidone iodine and hypochlorous acid were tested at short duration exposure times for 15 min against 3 day mature biofilms of Staphylococcus aureus and Pseudomonas aeruginosa; (ex vivo) hypochlorous acid was tested in a porcine skin explant model with 12 cycles of 10 min exposure, over 24 h, against 3 day mature P. aeruginosa biofilms; and (in vivo) 4% w/v Melaleuca oil was applied for 15 min exposure, daily, for 7 days, in 10 patients with chronic non-healing diabetic foot ulcers complicated by biofilm.

Results

In vitro assessment demonstrated variable efficacy in reducing biofilms ranging from 0.5 log₁₀ reductions to full eradication. Repeated instillation of hypochlorous acid in a porcine model achieved <1 log₁₀ reduction (0.77 log₁₀, P = 0.1). Application of 4% w/v Melaleuca oil in vivo resulted in no change to the total microbial load of diabetic foot ulcers complicated by biofilm (median log₁₀ microbial load pre-treatment = 4.9 log₁₀ versus 4.8 log₁₀, P = 0.43).

Conclusions

Short durations of exposure to topical antimicrobial wound solutions commonly utilized by clinicians are ineffective against microbial biofilms, particularly when used in vivo. Wound solutions should not be used as a sole therapy and clinicians should consider multifaceted strategies that include sharp debridement as the gold standard.

Novel Methods for Efficacy Testing of Disinfectants – Part I

The pathogens which are the effective transmitters of various infections pose a serious problem in restraining their interference in maintaining a sterile environment. The practical applicability of traditional methods of disinfection is restricted due to their cumbersomeness, toxic product generation, and cost-effectiveness. Therefore, the objective of the current review is to elaborate the efficacies and limitations of various novel disinfectants that can show their activity in a few minutes of treatment. The expected outcome would be feasibility for selection of a favorable disinfectant through various technologies that can generate uniform results and form a basis for the true estimation required parameters. Hence, the current paper ends with the consideration of unique new techniques that distinguishes their simplicity, safety, and efficacy in generating a sterile environment.

N-acetyl cysteine versus chlorhexidine mouthwashes in prevention and treatment of experimental gingivitis: a randomized, triple-blind, placebo-controlled clinical trial

OBJECTIVES

To compare the efficacy of N-acetyl cysteine (NAC) mouthwash with chlorhexidine (CHX) in prevention and treatment of experimental gingivitis MATERIALS AND METHODS: Sixty subjects were assigned randomly and blindly into one of three equal groups: NAC, CHX, or placebo group. The study was conducted in two stages: preventive and treatment substudies. Professional prophylaxis was performed ahead of starting the preventive substudy. Then, the subjects were instructed to stop oral hygiene practices and begin rinsing twice/day with 15 ml of the assigned mouthwash (1.25% NAC, 0.2% CHX, or inert base). Plaque index (PI), gingival index (GI), and papillary bleeding index (PBI) were measured at baseline, 7, 14, and 21 days. The treatment substudy started on day 21 in which the subjects in the placebo group (now with established experimental gingivitis) were assigned to NAC (n = 10) or CHX (n = 10); the abovementioned indices were measured at 28 and 35 days. Efficacy of these interventions was compared.

RESULTS

All groups accumulated plaque and developed some degree of gingivitis: full-blown in the placebo group and remarkably mild in the CHX group. NAC had slight preventive properties at days 14 and 21. In the treatment substudy, CHX was associated with remarkable reduction in plaque and gingivitis while NAC resulted in insignificant reductions.

CONCLUSIONS

1.25% NAC is marginally effective in prevention and treatment of experimental gingivitis.

CLINICAL RELEVANCE

When compared with the placebo, NAC showed promising preventive and treatment effects of gingivitis that deserve further development and studies.

TRIAL REGISTRATION

ISRCTN31352091.

Saliva-coated titanium biosensor detects specific bacterial adhesion and bactericide caused mass loading upon cell death

Bacteria adhering to implanted medical devices can cause invasive microbial infections, of e.g. skin, lung or blood. In dentistry, Streptococcus gordonii is an early oral colonizer initiating dental biofilm formation and also being involved in life-threatening infective endocarditis. To treat oral biofilms, antibacterial mouth rinses are commonly used. Such initial biomaterial-bacteria interactions and the influence of antibacterial treatments are poorly understood and investigated here in situ by quartz crystal microbalance with dissipation monitoring (QCM-D). A saliva-coated titanium (Ti) biosensor is applied to analyze possible specific signal patterns indicating microbial binding mechanisms and bactericide-caused changes in bacterial film rigidity or cell leakage caused by a clinically relevant antibacterial agent (ABA), i.e., a mouth rinse comprising chlorhexidine (CHX) and cetylpyridinium chloride (CPC). Apparent missing mass effects during the formation of microscopically proven dense and vital bacterial films indicate punctual, specific binding of S. gordonii to the saliva-coated biosensor, compared to unspecific adhesion to pure Ti. Coincidentally to ABA-induced killing of surface-adhered bacteria, an increase of adsorbed dissipative mass can be sensed, contrary to the prior mass-loss. This suggests the acoustic sensing of the leakage of cellular content caused by bacterial cell wall rupturing and membrane damage upon the bactericidal attack. The results have significant implications for testing bacterial adhesion mechanisms and cellular integrity during interaction with antibacterial agents.

Efficacy of Ocimum sanctum, Aloe vera and chlorhexidine mouthwash on gingivitis: A randomized controlled comparative clinical study

Background

The medicinal plants are widely used for curing various diseases in day-to-day practice. Ocimum sanctum (Tulsi) is one such popular herb in Ayurvedic medicine, which is widely used in the treatment of several systemic diseases because of its antimicrobial property. Aloe vera is also widely known for its medicinal uses in wound healing and its anti-inflammatory properties. However, studies documenting the effect of O. sanctum and A. vera in treating gingivitis are rare.

Aim

The aim of this study was to assess the effectiveness of two herbal mouthwashes in comparison with chlorhexidine mouthwash on gingivitis.

Materials and Methods

A double-blind randomized placebo-controlled clinical trial, wherein sixty patients were randomly allocated into three study groups. (1) O. sanctum mouthwash (n = 20) (2) A. vera mouthwash (n = 20) and (3) Chlorhexidine mouthwash (n = 20). All groups were treated with scaling and asked to rinse with respective mouthwashes twice daily for 1 month. Clinical parameters such as plaque index (PI), gingival index (GI), and sulcus bleeding index (BI) were recorded at baseline, after 15 days and after 30 days, respectively.

Results

Results of the study showed that O. sanctum, A. vera and chlorhexidine are equally effective in reducing plaque, gingival, and bleeding indices at 30-day interval. However, no significant reductions in PI, GI and BI in 15-day interval in group 1 and group 2 when compared with chlorhexidine were evident.

Conclusion

The results in the present study indicate that O. sanctum and A. vera may prove to be as effective as chlorhexidine mouthwash in its ability in reducing all the three indices by reducing plaque accumulation, gingival inflammation and bleeding when used in the long-term follow-up.

Hydrogen peroxide masks the bitterness of chlorhexidine mouthwash without affecting its antibacterial activity

Background:

Chlorhexidine (CHX) is an antiseptic mouthwash widely used as the gold standard for inhibiting plaque formation. However, the bitter taste of CHX limits patient compliance. We developed a 0.12% CHX and 1.5% hydrogen peroxide (H₂O₂) mouthwash that masked the bitter taste of CHX. This study evaluated the antibacterial activity and subject satisfaction of the developed mouthwash.

Materials and Methods:

Three mouthwashes were used as follows: (1) a commercial 0.12% CHX mouthwash, (2) a prepared 0.12% CHX mouthwash containing 1.5% H₂O₂, and (3) a prepared 0.12% CHX mouthwash. A disc diffusion assay was performed to determine the antibacterial activity of each mouthwash against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. To assess subject satisfaction with each mouthwash, a satisfaction questionnaire was completed immediately after rinsing with each mouthwash.

Results:

The antibacterial activities of the three mouthwashes were similar. Moreover, the questionnaire results revealed that the level of satisfaction was significantly higher for the 0.12% CHX/1.5% H₂O₂ mouthwash compared with the other mouthwashes.

Conclusion:

The 0.12% CHX/1.5% H₂O₂ mouthwash revealed a similar antibacterial activity as the CHX standard against periodontal disease pathogens. In addition, the subjects were more satisfied with the new formula compared with 0.12% CHX alone. These data suggest that the 0.12% CHX/1.5% H₂O₂ formulation is an alternative antibacterial mouthwash to avoid the unpleasant CHX side effects.

Efficacy of chlorhexidine rinses after periodontal or implant surgery: a systematic review

BACKGROUND

Biofilm management and infection control are essential after periodontal and implant surgery. In this context, chlorhexidine (CHX) mouth-rinses are frequently recommended post-surgically. Despite its common use and many studies in this field, a systematic evaluation of the benefits after periodontal or implant surgery is-surprisingly-still missing.

OBJECTIVES

To evaluate the benefits of chlorhexidine rinsing after periodontal or implant surgery in terms of plaque and inflammation reduction potential. Furthermore, to screen whether the concentration changes or additives in CHX solutions reduce side effects associated with its use.

MATERIALS AND METHODS

A systematic literature search was performed for clinical trials, which compared CHX rinsing after periodontal or implant surgery with rinsing using placebo, non-staining formulations, or solutions with reduced concentrations of the active compound. Four databases (Medline, PubMed, Embase, Cochrane) were searched up to June 2018. Two reviewers independently identified and screened the literature.

RESULTS

From 691 titles identified, only eleven publications met the inclusion criteria and were finally included. Mainly early publications assessed the benefits of CHX over placebo rinsing, whereas more recent publications focused more on the evaluation of new formulations with regard to effectiveness and side effects. The use of CHX after surgery showed in general significant reduction in plaque (means of 29-86% after 1 week) and bleeding (up to 73%) as compared to placebo. No consensus, however, was found regarding the most beneficial CHX formulation avoiding side effects.

CONCLUSION

Chlorhexidine rinsing helps to reduce biofilm formation and gingival inflammation after surgery. However, no additional reduction of periodontal probing depth over any given placebo or control solution could be found irrespective of whether CHX was used or not. The use of additives such as antidiscoloration systems (ADS) or herbal extracts may reduce side effects while retaining efficacy.

CLINICAL RELEVANCE

Within the limitations of this review, it can be concluded that CHX may represent a valuable chemo-preventive tool immediately after surgery, during the time period in which oral hygiene capacity is compromised. To reduce the side effects of CHX and maintain comparable clinical effects, rinsing with less concentrated formulations (e.g., 0.12%) showed the most promising results so far.

Redox/pH dual-controlled release of chlorhexidine and silver ions from biodegradable mesoporous silica nanoparticles against oral biofilms

BACKGROUND

Oral plaque biofilms pose a threat to periodontal health and are challenging to eradicate. There is a growing belief that a combination of silver nanoparticles and chlorhexidine (CHX) is a promising strategy against oral biofilms.

PURPOSE

To overcome the side effects of this strategy and to exert maximum efficiency, we fabricated biodegradable disulfide-bridged mesoporous silica nanoparticles (MSNs) to co-deliver silver nanoparticles and CHX for biofilm inhibition.

MATERIALS AND METHODS

CHX-loaded, silver-decorated mesoporous silica nanoparticles (Ag-MSNs@CHX) were fabricated after CHX loading, and the pH- and glutathione-responsive release profiles of CHX and silver ions along with their mechanism of degradation were systematically investigated. Then, the efficacy of Ag-MSNs@CHX against Streptococcus mutans and its biofilm was comprehensively assessed by determining the minimum inhibitory concentration, minimum bactericidal concentration, minimal biofilm inhibitory concentration, and the inhibitory effect on S. mutans biofilm formation. In addition, the biosafety of nanocarriers was evaluated by oral epithelial cells and a mouse model.

RESULTS

The obtained Ag-MSNs@CHX possessed redox/pH-responsive release properties of CHX and silver ions, which may be attributed to the redox-triggered matrix degradation mechanism of exposure to biofilm-mimetic microenvironments. Ag-MSNs@CHX displayed dose-dependent antibacterial activity against planktonic and clone formation of S. mutans. Importantly, Ag-MSNs@CHX had an increased and long-term ability to restrict the growth of S. mutans biofilms compared to free CHX. Moreover, Ag-MSNs@CHX showed less cytotoxicity to oral epithelial cells, whereas orally administered Ag-MSNs exhibited no obvious toxic effects in mice.

CONCLUSION

Our findings constitute a highly effective and safe strategy against biofilms that has a good potential as an oral biofilm therapy.

Characteristics of Local Delivery Agents for Treating Peri-Implantitis on Dental Implant Surfaces: A Preclinical Study

Local delivery agents (LDAs) are widely used in peri-implantitis treatments. The aim of this study was to identify LDAs remaining on the dental implant surfaces and to analyze the components of these residues after applying various cleaning methods. Implants were prepared with a sand-blasted, large-grit, acid-etched surface. Four kinds of LDAs were applied on the implant surfaces: chlorhexidine gel (group 2), tetracycline solution (group 3), and 2 kinds of minocycline hydrochloride agents (groups 4 and 5). Group 1 received normal saline as a control. Two cleaning methods were applied for different durations as follows: (1) running distilled water for 10 seconds (subgroup A), 5 minutes (subgroup B), and 15 minutes (subgroup C); and (2) water spray of a dental-unit chair for 10 seconds (subgroup D) and 5 minutes (subgroup E). Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to analyze the surface morphology and residue components for all implants. The amount of LDA removed from the implant surfaces in groups 1, 2, 3, and 5 increased with the cleaning duration and pressure. However, Minocline remained coated on the implant surfaces in group 4 under all cleaning conditions. Minocline could not be cleaned off well by water due to its hydrophobicity. Therefore, directly using this agent on implant surfaces with peri-implantitis should be carefully considered. The presence of LDA residues without drug efficacies on implant surfaces might interfere with reosseointegration and act as a reservoir of microorganisms.