Effects of low dose chlorhexidine mouthrinses on oral bacteria and salivary microflora including those producing hydrogen sulfide

Role of Hydrogen Sulfide in Oral Disease

Oral diseases are among the most common human diseases yet less studied. These diseases affect both the physical, mental, and social health of the patients resulting in poor quality of life. They affect all ages, although severe stages are mostly observed in older individuals. Poor oral hygiene, genetics, and environmental factors contribute enormously to the development and progression of these diseases. Although there are available treatment options for these diseases, the recurrence of the diseases hinders their efficiency. Oral volatile sulfur compounds (VSCs) are highly produced in oral cavity as a result of bacteria activities. Together with bacteria components such as lipopolysaccharides, VSCs participate in the progression of oral diseases by regulating cellular activities and interfering with the immune response. Hydrogen sulfide (H2S) is a gaseous neurotransmitter primarily produced endogenously and is involved in the regulation of cellular activities. The gas is also among the VSCs produced by oral bacteria. In numerous diseases, H2S have been reported to have dual effects depending on the cell, concentration, and donor used. In oral diseases, high production and subsequent utilization of this gas have been reported. Also, this high production is associated with the progression of oral diseases. In this review, we will discuss the production of H2S in oral cavity, its interaction with cellular activities, and most importantly its role in oral diseases.

Oral bacterial decontamination using an innovative prototype for photocatalytic disinfection

OBJECTIVES

The aim of this study was to evaluate the effectiveness of a prototype photocatalytic device for bacterial decontaminations of the oral cavity.

METHODS

Sixty-four subjects (18-65) were selected and randomly assigned to eight groups (n = 8), according to oral disinfection protocol: (G1): distilled water (control); (G2): 1.5% hydrogen peroxide (HP); (G3): 3.0% HP; (G4): 0.12% chlorhexidine (CHX); (G5): Germinator; (G6): 1.5% HP + Germinator; (G7): 3.0%HP + Germinator; (G8): 0.12% CHX + Germinator. Stimulated saliva was collected before and after a 3-min mouthwash and/or Germinator application. The patients were kept relaxed and retained saliva 5-10 min, spitting out into the tube for 3 min. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) after culturing on blood agar plates. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 5%) for statistical significance.

RESULTS

The highest bacterial reduction was observed in groups 3 (3.0% HP), 6 (1.5% HP + Germinator), and 7 (3.0% + Germinator), with no statistically significant difference between them (p > 0.05). Groups 6 (1.5% HP + Germinator) and 8 (0.12% CHX + Germinator) showed higher bacterial reduction than groups 2 (1.5% HP) and 4 (0.12% CHX) (p < 0.05). Finally, group 5 (Germinator) showed higher bacterial reduction than control group (DW) and group 4 (0.12% CHX) (p < 0.05).

CONCLUSIONS

The photocatalytic disinfection was effective against oral bacteria and improved the antimicrobial action of 1.5% HP and 0.12%.

CLINICAL SIGNIFICANCE

The photocatalytic disinfection can be an alternative protocol to provide the oral decontamination.

Efficacy of antioxidant mouthwash in the reduction of halitosis: A randomized, double blind, controlled crossover clinical trial

Background/purpose

Halitosis is the unpleasant and offensive odour in exhaled air, which is linked to the presence of volatile sulphur compounds (VSC). Different mouthwashes have been used to treat halitosis. The objective of this study was to test the effect of an antioxidant (AO) mouthwash, and mouthwash containing [0.05% chlorhexidine, 0.05% cetylpyridinium chloride, and 0.14% zinc lactate (CHX-CPC-Zn)] on VSC.

Material and methods

Thirty-five subjects with halitosis participated in this clinical trial. At the baseline visit, a breath sample was taken and analyzed for the level of hydrogen sulphide (H₂S), methyl mercaptan (CH₃SH), and dimethyl sulphide (CH₃SCH₃) using portable gas chromatography (OralChroma™). Two mouthwashes were randomly provided to each subject in addition to saline solution (NaCl 0.9%) as control. Subjects were instructed to rinse with 20 ml of the mouthwash for 1 min twice daily for 2 weeks. At second visit, post-treatment breath sample was taken. Afterward, the patient was asked to refrain from using mouthwash for a washout period of 1 week. A similar procedure was repeated for each mouthwash interval.

Results

No significant differences in VSC level between all three groups were detected at baseline. A significant reduction in VSC level was obtained after using CHX-CPC-Zn mouthwash. On other hand, both AO mouthwash and saline had no significant impact on the level of VSC.

Conclusion

CHX-CPC-Zn mouthwash has a significant effect on VSC level reduction in subjects with confirmed halitosis. Besides, using AO mouthwash regularly for 2 weeks did not have any impact on improving the level of halitosis.

Rapid Antibiofilm Effect of Ag/ZnO Nanocomposites Assisted by Dental LED Curing Light against Facultative Anaerobic Oral Pathogen Streptococcus mutans

The integration of nanomaterials with clinical therapeutic instruments is a promising approach to improve the effects of nanomaterials. We reported an efficient synergistic antibacterial strategy formed through the combination of Ag/ZnO nanocomposites with a light-emitting diode (LED) curing light, which is a commonly used small instrument in dental clinics. The as-designed integration depicted a significantly enhanced bactericidal effect on facultative anaerobic oral pathogen Streptococcus mutans (S. mutans) both in planktonic and biofilm phases over a very short irradiation time (≤5 min). Further study showed that the combination of LED and Ag/ZnO nanocomposites induced more ·OH and ·O₂^- generation, which is responsible for the enhanced antibacterial activity. Moreover, this combination could destroy S. mutans biofilm by killing the bacteria embedded within biofilm, inhibiting exopolysaccharide production and down-regulating the biofilm-related gene expression. Therefore, it is proposed that this combination could be applied in dental clinics to realize dental caries prevention and dental restoration simultaneously.

In situ chlorhexidine substantivity on saliva and plaque-like biofilm: influence of circadian rhythm

BACKGROUND

The aim of the present study is to assess in situ substantivity of a single mouthrinse with 0.2% chlorhexidine (CHX) on saliva and on undisturbed de novo plaque-like biofilm (PL-biofilm), differentiating between two times of application: 1) CHX mouthrinse in the morning; and 2) CHX mouthrinse at night.

METHODS

The study participants were 10 healthy volunteers who wore an individualized splint with glass disks for 48 hours to boost the growth of PL-biofilm. Saliva samples were collected, and two disks were removed from each volunteer's splint at 8, 10, and 12 hours after performing a mouthrinse with 0.2% CHX at 7:00 am (M-0.2% CHX-diurnal) and 1:00 am (M-0.2% CHX-nocturnal). The saliva and plaque samples were analyzed by epifluorescence and confocal laser scanning microscopy, respectively, using a green fluorescent nucleic acid stain/propidium iodide staining.

RESULTS

With M-0.2% CHX-diurnal, the frequency of vital bacteria in saliva was significantly higher than in the PL-biofilm at 8, 10, and 12 hours after mouthrinse. After M-0.2% CHX-nocturnal, the frequency of vital bacteria in saliva was significantly lower than in the PL-biofilm at 8 hours and higher than in the PL-biofilm at 12 hours after mouthrinse.

CONCLUSION

These results support the more active physiologic dynamics of the salivary flora and the possible reservoir function associated with the structure of undisturbed de novo PL-biofilm.

Effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia in children undergoing cardiac surgery

OBJECTIVE

To evaluate the effect of oral hygiene with 0.12% chlorhexidine gluconate on the incidence of nosocomial pneumonia and ventilator-associated pneumonia (VAP) in children undergoing cardiac surgery.

DESIGN

Prospective, randomized, double-blind, placebo-controlled trial.

SETTING

Pediatric intensive care unit (PICU) at a tertiary care hospital.

PATIENTS

One hundred sixty children undergoing surgery for congenital heart disease, randomized into 2 groups: chlorhexidine (n = 87) and control (n = 73).

INTERVENTIONS

Oral hygiene with 0.12% chlorhexidine gluconate or placebo preoperatively and twice a day postoperatively until PICU discharge or death.

RESULTS

Patients in experimental and control groups had similar ages (median, 12.2 vs 10.8 months; P = .72) and risk adjustment for congenital heart surgery 1 score distribution (66% in category 1 or 2 in both groups; P = .17). The incidence of nosocomial pneumonia was 29.8% versus 24.6% (P = .46) and the incidence of VAP was 18.3% versus 15% (P = .57) in the chlorhexidine and the control group, respectively. There was no difference in intubation time (P = .34), need for reintubation (P = .37), time interval between hospitalization and nosocomial pneumonia diagnosis (P = .63), time interval between surgery and nosocomial pneumonia diagnosis (P = .10), and time on antibiotics (P = .77) and vasoactive drugs (P = .16) between groups. Median length of PICU stay (3 vs 4 days; P = .53), median length of hospital stay (12 vs 11 days; P = .67), and 28-day mortality (5.7% vs 6.8%; P = .77) were also similar in the chlorhexidine and the control group.

CONCLUSIONS

Oral hygiene with 0.12% chlorhexidine gluconate did not reduce the incidence of nosocomial pneumonia and VAP in children undergoing cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00829842 .

In vitro assessment of shiitake mushroom (Lentinula edodes) extract for its antigingivitis activity

Gingivitis is a preventable disease characterised by inflammation of the gums due to the buildup of a microbial biofilm at the gingival margin. It is implicated as a precursor to periodontitis, a much more serious problem which includes associated bone loss. Unfortunately, due to poor oral hygiene among the general population, gingivitis is prevalent and results in high treatment costs. Consequently, the option of treating gingivitis using functional foods, which promote oral health, is an attractive one. Medicinal mushrooms, including shiitake, have long been known for their immune system boosting as well as antimicrobial effects; however, they have not been employed in the treatment of oral disease. In the current study, the effectiveness of shiitake mushroom extract was compared to that of the active component in the leading gingivitis mouthwash, containing chlorhexidine, in an artificial mouth model (constant depth film fermenter). The total bacterial numbers as well as numbers of eight key taxa in the oral community were investigated over time using multiplex qPCR. The results indicated that shiitake mushroom extract lowered the numbers of some pathogenic taxa without affecting the taxa associated with health, unlike chlorhexidine which has a limited effect on all taxa.

MPC-polymer reduces adherence and biofilm formation by oral bacteria

Oral biofilms such as dental plaque cause dental caries and periodontitis, as well as aspiration pneumonia and infectious endocarditis by translocation. Hence, the suppression of oral biofilm formation is an issue of considerable importance. Mechanical removal, disinfectants, inhibition of polysaccharide formation, and artificial sugar have been used for the reduction of oral biofilm. From the viewpoint of the inhibition of bacterial adherence, we investigated whether aqueous biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC)-polymer can reduce streptococcal colonization and biofilm formation. We examined the effects of MPC-polymer on streptococcal adherence to saliva-coated hydroxyapatite and oral epithelial cells, and the adherence of Fusobacterium nucleatum to streptococcal biofilm. MPC-polymer application markedly inhibited both the adherence and biofilm formation of Streptococcus mutans on saliva-coated hydroxyapatite and streptococcal adherence to oral epithelial cells, and reduced the adherence of F. nucleatum to streptococcal biofilms. A small-scale clinical trial revealed that mouthrinsing with MPC-polymer inhibited the increase of oral bacterial numbers, especially of S. mutans. These findings suggest that MPC-polymer is a potent inhibitor of bacterial adherence and biofilm development, and may be useful to prevent dental-plaque-related diseases. (UMIN Clinical Trial Registry UMIN000003471).

In vivo substantivity of 0.12% and 0.2% chlorhexidine mouthrinses on salivary bacteria

The in vivo antimicrobial activity of 0.12% and 0.2% chlorhexidine (CHX) on the salivary flora up to 7 h after its application, using epifluorescence microscopy with the SYTO 9/propidium iodide dual staining, was evaluated. Fifteen volunteers performed a single mouthrinse with sterile water (SM-water), a single mouthrinse with 0.12% CHX (0.12% SM-CHX) and a single and double mouthrinse with 0.2% CHX (0.2% SM-CHX and 0.2% DM-CHX). Samples of saliva were taken at 30 s, and 1, 3, 5, and 7 h after each application. In comparison with SM-water, 0.2% CHX (SM and DM) showed a significant antibacterial effect up to 7 h after the mouthrinse, whereas this effect only persisted up to 5 h after the 0.12% SM-CHX mouthrinse. On comparing the two concentrations of CHX, significantly higher percentages of bacterial vitality were observed in all the saliva samples after the use of 0.12% CHX than after 0.2% CHX. On comparison of the 0.2% SM-CHX and 0.2% DM-CHX, significantly higher percentages of live bacteria were observed in the saliva samples taken at 1, 3, 5, and 7 h after the single mouthrinse compared with the double mouthrinse. The 0.2% CHX mouthrinse had the greatest antimicrobial activity on the salivary flora up to 7 h after its application, with a progressive recovery in bacterial vitality. The differences observed with respect to the 0.12% CHX mouthrinse demonstrate the influence of the concentration on its immediate antimicrobial activity and substantivity.

Evaluation of chlorhexidine substantivity on salivary flora by epifluorescence microscopy

OBJECTIVE

To evaluate the in vivo antimicrobial activity of chlorhexidine (CHX) in saliva 7 h after its application using an epifluorescence microscopy technique.

SUBJECTS AND METHODS

Fifteen volunteers performed a single mouthrinse with sterile water (SM-water) and with 0.2% CHX (SM-0.2% CHX). Saliva samples were taken at 30 s and 1, 3, 5 and 7 h after each application. The bacterial suspension was mixed with the SYTO 9/propidium iodide staining and observed using an Olympus BX51 microscope. The mean percentage of viable bacteria was calculated for each sample.

RESULTS

In comparison with baseline values, the frequency of viable bacteria decreased significantly at 30 s after the SM-0.2% CHX (P < 0.001) and presented significant antibacterial activity up to 7 h after the mouthrinse (P < 0.001). In comparison with SM-water, the prevalence of viable bacteria was significantly lower at 30 s after the SM-0.2% CHX (P < 0.001) and showed a significant antibacterial effect up to 7 h after the mouthrinse (P < 0.001).

CONCLUSIONS

Epifluorescence microscopy permits evaluating the antimicrobial activity of CHX on the salivary flora in real-time. Fluorescence assays could be particularly useful to analyse simultaneously the effect of antimicrobials that alter the cytoplasmic membrane integrity on different oral ecosystems.

The Impact of a Low-Frequency Chlorhexidine Rinsing Schedule on the Subgingival Microbiota (the TEETH clinical trial)

BACKGROUND

Information on the efficacy of chlorhexidine (CHX) rinsing on the subgingival microbiota is limited. This study tested if intermittent CHX rinsing over 5 years had an impact on the subgingival microbiota.

METHODS

Subgingival plaque samples were analyzed by the checkerboard DNA-DNA hybridization method in a double-blind randomized CHX rinse study.

RESULTS

A total of 210 subjects were included. The mean age of the subjects was 71.7 (+/- 4.1) years, and 56.2% were women. Evidence of alveolar bone loss was found in 39% of subjects. Bacterial loads were not correlated significantly with probing depth. At year 5, subjects in the CHX rinse group with no evidence of bone loss presented with lower total bacterial counts than control subjects with no bone loss. The levels of the following bacteria were significantly lower in the CHX group: Lactobacillus acidophilus (P <0.05), Eikenella corrodens (P <0.05), Fusobacterium nucleatum sp. nucleatum (P <0.01), Treponema denticola (P <0.05), Leptotrichia buccalis (P <0.05), and Eubacterium saburreum (P <0.05). No differences in bacterial loads were found between CHX and control rinse subjects with alveolar bone loss.

CONCLUSIONS

Older subjects with or without periodontitis carry a large variety of bacteria associated with periodontitis. Intermittent rinsing with CHX may provide a preventive benefit in reducing levels of bacteria but only in subjects without alveolar bone loss.

Bacterial colonization immediately after installation on oral titanium implants

BACKGROUND

Information on bacterial colonization immediately after dental implant insertion is limited.

AIMS

(1) To assess the early colonization on titanium implants immediately after placement and throughout the first 12 post-surgical weeks, (2) to compare the microbiota at interproximal subgingival implant and adjacent tooth sites.

MATERIAL AND METHODS

Subgingival plaque samples from implant and neighbouring teeth were studied by checkerboard DNA-DNA hybridization before surgery, 30 min after implant placement, and 1, 2, 4, 8, and 12 weeks after surgery.

RESULTS

Comparing bacterial loads at implant sites between 30 min after placement with 1-week data showed that only the levels of Veillonella parvula (P<0.05) differed with higher loads at week 1 post-surgically. Week 12 data demonstrated significantly higher bacterial loads for 15/40 species at tooth sites compared with pre-surgery (P-values varying between 0.05 and 0.01). Between the period immediately after surgery and 12 weeks at implant sites, 29/40 species was more commonly found at 12 weeks. Included among these bacteria at implant sites were Porphyromonas gingivalis (P<0.05), Tannerella forsythia, (P<0.01), and Treponema denticola (P<0.001). Immediately post-surgery 5.9% of implants, and 26.2% of teeth, and at week 12, 15% of implants, and 39.1% of teeth harbored Staphylococcus aureus. Comparing tooth and implant sites, significantly higher bacterial loads were found at tooth sites for 27/40 species after 30 min following implant placement. This difference increased to 35/40 species at 12 weeks post-surgically.

CONCLUSIONS

Bacterial colonization occurred within 30 min after implant placement. Early colonization patterns differed between implant and tooth surfaces.

Postcare Recommendations for Emergency Department Wounds

Diligent posttreatment wound care management undoubtedly will improve wound outcome and patient satisfaction. There are limited recommendations in the literature to guide management plans. Nevertheless patients must receive specific instructions to complete wound care. These instructions should include whether a dressing is indicated, which dressing should be used, the duration of use, and the method of application. The plan must explain clearly the reasons for returning for further medical attention, for follow-up, for routine removal of sutures/staples, and an earlier return for possible concerns of infection or dehiscence. Preprinted discharge instruction sheets are useful, and illustrations can be helpful.

An ex-vivo multiplexed antibacterial test on oral microflora

BACKGROUND/AIMS

Characterized clinical strains of oral bacteria are utilized to examine the antimicrobial efficacy of oral care formulations. A demonstration of antimicrobial effects of formulations on microbial samples obtained from the human mouth offers advantages, i.e. incorporates the considerable microbial diversity of this environment with bacteria harvested from naturally occurring biofilms to form the focus of this investigation.

MATERIALS AND METHODS

Samples of oral flora from each adult subject were briefly treated (2 min) with test and control formulations and plated on appropriate agar for multiplexed antimicrobial effects on functional groups of oral bacteria associated with specific conditions.

RESULTS

Ex-vivo treatments of oral samples with the triclosan/copolymer dentifrice demonstrated significant dose-dependent antimicrobial effects compared with a control formulation on anaerobic and facultative oral bacteria from a group of 16 volunteers (P < 0.05) with reproducible effects observed in three separate trials (P < 0.05). Similarly, significant dose-dependent effects were noted with chlorhexidine mouthrinses (P < 0.05). A simultaneous assessment of the effects of these formulations on several functional classes of oral bacteria associated with specific oral conditions such as dental caries and oral malodor demonstrated multiplexed antimicrobial activity (P < 0.05).

CONCLUSIONS

A rapid procedure using small volumes of human oral samples and well-known formulations demonstrates ex-vivo multiplexed antimicrobial effects on functional groups of bacteria with both dentifrices and mouthrinses. Modifications of this approach may include antibacterial effects over time with formulations at clinically relevant concentrations, effects of novel agents or samples from subjects stratified on the basis of their clinical status.