Antimicrobial Mouthrinses For Plaque and Gingivitis Control

Maintaining a consistent at-home oral hygiene regimen is essential to improved oral health and the control of plaque and gingivitis. Even patients with strong oral hygiene skills may have areas where biofilm remains untouched, raising the risk of caries and/or periodontal diseases. Nearly half of the United States population has some form of periodontal disease, and 70% of adults age 65 and older have this inflammatory disease.¹ Controlling plaque and gingivitis can help to prevent periodontal diseases. Fortunately, clinicians have several formulations of dentifrices, gels, and mouthrinses that serve as important adjuncts to mechanical methods of biofilm removal. This review will focus on the evidence for using chlorhexidine gluconate (CHX), essential oils (EO), and cetylpyridinium chloride (CPC) mouthrinses that are available in the US for plaque and gingivitis control.

Antimicrobial mouthrinses have been investigated as a therapy to reduce plaque and gingivitis. They are formulated to negatively impact the formation, growth, and maturation of oral biofilms.² Mouthrinses are popular with patients because they are easy to use and have minimal side effects. In addition, about 20% of the oral environment is made up of tooth surfaces but plaque biofilm can occupy areas in the remaining 80% of the oral environment, including the oral mucosa and tongue.³ It is possible that a mouthrinse could provide an antimicrobial effect to the entire mouth.

The most widely investigated antimicrobial mouthrinses are those containing CHX, EO, and CPC. Systematic reviews on these rinses have reported impressive plaque and gingivitis reduction in some cases.^4,5

CHLORHEXIDINE GLUCONATE

CHX is the most effective anti-plaque/anti-gingivitis rinse available. In the US, it is sold by prescription only at a 0.12% concentration and a pH of 5.5 to 6.0. While most of the products contain 11.6% alcohol, alcohol-free formulations are available. The rinse works by altering the bacterial adsorption, reducing the pellicle formulation, and altering the bacterial cell wall, causing lysis of the contents. The substantivity of CHX is excellent, with 30% retention in the oral cavity after rinsing and it remains effective for 8 hours to 12 hours.⁶

CHX is approved for the reduction of plaque and gingivitis, but not periodontitis. The reduction of gingivitis, however, may impact the prevention of chronic periodontitis in some patients. A recent systematic review by Van Strydonck et al⁵ reported a 33% reduction in plaque and 26% decrease in gingivitis among studies lasting ? 4 weeks. Studies in the review confirmed CHX to be effective in the reduction of plaque, bleeding, and gingivitis when used as an adjunctive product. CHX should be used by patients twice per day for at least 20 seconds as a 15-ml rinse. Adverse effects include staining of enamel, alteration of taste, and increased calcified deposits.

ESSENTIAL OILS

EO rinses consist of a combination of thymol, menthol, and eucalyptol with methyl salicylate. Alcohol content varies from 21.0% to 26.9%. Depending on the concentration, EO rinses can either disrupt the cell wall and precipitate cell proteins (higher concentration) or inactivate some essential enzymes (lower concentration). They also may exert antioxidant activity.⁷ Gunsolley⁸ concluded that EO rinses are among the most efficacious over-the-counter mouthrinses available in the US. The author reported data on mean plaque reduction of 27% and 18.2% in gingival inflammation reduction in mouthrinses studies lasting a minimum of 6 months, combined with mechanical plaque control.⁸ A recent meta-analysis was conducted by Araujo et al⁹ with the purpose of evaluating the site-specific effectiveness of EO mouthrinses with mechanical plaque control vs mechanical plaque control alone. The analysis consisted of 29 industry-sponsored clinical trials that investigated the anti-plaque, anti-gingivitis effects of EO mouthrinses conducted over 32 years. All studies were designed to meet criteria and regulations outlined by the American Dental Association and the US Food and Drug Administration. The results reported that, after 6 months of use, clinicians could expect approximately 45% of patients to have at least 50% of sites without gingivitis. Approximately 37% of patients would have at least 50% of the sites without plaque when using mechanical plaque control and an EO mouthrinse twice daily for at least 6 months.

Questions frequently arise about the alcohol content of EO mouthrinses. Boyle et al² recently reported that the use of an EO mouthrinse containing alcohol does not pose an increased risk of oral cancer when used as directed. Clinicians should not recommend antimicrobial mouthrinses containing alcohol to patients who are recovering or current alcoholics or to children younger than 12.

Patients should be instructed to rinse with 20 ml for 30 seconds. Contraindications include a burning sensation during use with certain formulations.

CETYLPYRIDINIUM CHLORIDE

CPC is a widely used cationic quaternary ammonium compound with a broad antimicrobial spectrum. Part of its molecule interacts with the bacterial cell membrane, which can cause cell growth inhibition and eventually cell death. It is mostly effective against Gram-positive bacteria and yeast.

When evaluating the 6-month clinical trials on the ability of mouthrinses to control plaque and gingivitis, Gunsolley⁸ concluded that CPC was weaker than CHX and EO. This was mostly because of the fact that few clinical trials tested the same formulations of CPC. Another review on CPC and plaque accumulation and gingival inflammation comes from Haps et al.10 The authors concluded that, when used as an adjunct to mechanical oral hygiene, CPC rinse provides a small but significant additional benefit on reducing both biofilm accumulation and gingival inflammation.¹⁰

CPC should be used as a 20-ml rinse twice a day. Reported side effects include increased calculus formation, staining, and occasional burning sensation.

ANTIMICROBIAL MOUTHRINSES USED AS IRRIGANTS

While clinicians have used antimicrobial rinses for in-office irrigation and in power instrumentation devices (eg, ultrasonics), the evidence does not support the benefits of a single professional episode of subgingival irrigation.¹¹ In addition, studies have found that use of water, through irrigation, is just as effective as the use of an antimicrobial in the device.¹¹ The reason is likely due to the quick elimination of fluids placed subgingivally due to the gingival crevicular fluid.¹¹

Automated interdental cleaning devices, such as water irrigators, have been used by patients for at-home care. In a classic study by Flemmig et al,¹² it was reported that irrigation with CHX rinse (0.06%) reduced plaque and gingival inflammation and was more effective than rinsing with CHX (0.12%) or water. A 2008 systematic review by Husseini et al¹³ reported that oral irrigation provided a beneficial adjunctive effect on bleeding on probing when compared to regular oral hygiene alone, but not in plaque removal. The authors noted several possible advantages to oral irrigation, including a reduction in inflammation caused by a change in the composition of pathogens in biofilm, which may reduce inflammation, as well as changes to the subgingival microbial environment.^12–15

RINSES CONTAINING NATURAL COMPOUNDS

Many consumers are seeking natural products for use in oral health care, as they are perceived as being safer than synthetic products.¹⁶ Only one systematic review was located that reported on natural-compound-containing mouthrinses as an adjunct to oral hygiene in the control of plaque and gingivitis. The authors concluded there is insufficient evidence to support the use of the natural-compound-containing mouthrinses and that more high-quality research is needed in this area.¹⁶

Some mouthrinses containing natural components, such as EO, have a long history of efficacy, showing strong antimicrobial and anti-inflammatory effects.^17,18 Other mouthrinses are available that contain herbal ingredients, such as Centella asiatica, Echinacea purpurea, and Sambucus nigra, which have been investigated for the reduction of inflammation and biofilm.¹⁹

NONTRADITIONAL MOUTHRINSES

Sodium hypochlorite (household bleach) has been investigated as an antimicrobial mouthrinse and irrigant.^20–22 Used as a diluted solution, it has been found to reduce plaque scores and signs of gingival inflammation. However, the studies are small and the applicability to larger populations is not known. Large clinical trials are needed to determine the efficacy of these rinses.

Oil pulling, originating from ancient Ayurvedic medicine, has been advocated as a method to remove harmful bacteria from the oral cavity to improve gingival health. Several oils have been used for this method, including sunflower, olive, and sesame seed oil, which is thought to react with saliva to produce a reaction similar to soap formation. The oil is swished in the mouth for up to 30 minutes before expectorating. One systematic review was located that evaluated the evidence of oil pulling.²³ Five studies conducted in India were included in the review for a total of 160 subjects. Authors noted that the review provides weak evidence of the benefits of oil pulling when compared with CHX mouthrinse or a placebo. They added that the safety or adverse effects of oil pulling are yet to be determined.²³

CONCLUSION

Clinicians should recommend antimicrobial mouthrinses to patients who would potentially benefit from their use. Mouthrinses should be used as adjuncts to mechanical plaque control (ie, brushing and interdental cleaning). The choice of mouthrinse should be based on the evidence available in the literature and both provider and patient preferences.

REFERENCES

1. Eke PI, Dye BA, Wei L, Thoronton-Evans GO, Genco RJ. CDC Periodontal Disease Surveillance Workgroup. Prevalence of periodontitis in adults in the United States: 2009 and 2010. J Dent Res. 2012;91:914–920.
2. Boyle P, Koechlin A, Autier P. Mouthwash use and the prevention of plaque, gingivitis and caries. Oral Dis. 2014;(Suppl 1):1–68.
3. Mager DL, Ximenez-Fyvie LA, Haffajee AD, Socransky SS. Distribution of selected bacterial species on intraoral surfaces. J Clin Periodontol. 2003;30:644–654.
4. Gunsolley JC. A meta-analysis of six-month studies of antiplaque and antigingivitis agents. J Am Dent Assoc. 2006;137:1649–1657.
5. Van Strydonck DA, Slot DE, Van der Velden U, et al. Effect of a chlorhexidine mouthrinse on plaque, gingival inflammation and staining in gingivitis patients: a systematic review. J Clin Periodontol. 2012;39:1042–1055.
6. Bonesvoll P, Lökken P, Rölla G, Paus PN. Retention of chlorhexidine in the human oral cavity after mouth rinses. Arch Oral Biol. 1974;19:209–212.
7. Van der Weijden FA, Van der Sluijs E, Ciancio SG, Slot DE. Can chemical mouthwash agents achieve plaque/gingivitis control? Dent Clin North Am. 2015;59:799–829.
8. Gunsolley JC. Clinical efficacy of antimicrobial rinses. J Dent. 2010;38(Suppl 1):S6–S10.
9. Araujo MWB, Charles CA, Weinstein RB, et al. Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque. J Am Dent Assoc. 2015;146:610–622.
10. Haps S, Slot DE, Berchier CE, Van der Weidjen GA. The effect of cetylpyridinium chloride-containing mouth rinses as adjuncts to toothbrushing on plaque and parameters of gingival inflammation: a systematic review. Int J Dent Hyg. 2008;6:290–303.
11. Greenstein G. Research, Science and Therapy Committee of the American Academy of Periodontology. Position paper: the role of supra- and subgingival irrigation in the treatment of periodontal diseases. J Periodontol. 2005;76: 2015–2027.
12. Flemmig TF, Newman MG, Doherty FM, Grossman E, Meckel AH, Bakdash MB. Supragingival irrigation with 0.06% chlorhexidine in naturally occurring gingivitis. I. 6 month clinical observations. J Periodontol. 1990;61;112–117.
13. Husseini A, Slot DE, Van der Weijden GA. The efficacy of oral irrigation in addition to a toothbrush on plaque and the clinical parameters of periodontal inflammation: a systematic review. Int J Dent Hyg. 2008;6:304–314.
14. Flemmig TF, Epp B, Funkenhauser Z, et al. Adjunctive supragingival irrigation with acetylsalicylic acid in periodontal supportive therapy. J Clin Periodontol. 1995;22:427–433.
15. Chaves ES, Korman KS, Manwell MA, Jones AA, Newhold DA, Wood RC. Mechanism of irrigation effects on gingivitis. J Periodontol. 1994;65:1016–1021.
16. Chen Y, Wong RW, McGrath C, Hagg U, Seneviratne CJ. Natural compounds containing mouthrinses in the management of dental plaque and gingivitis: a systematic review. Clin Oral Investig. 2014;18:1–16.
17. Van Leeuwen MP, Slot E, Van der Weijden GA. Essential oils compared to chlorhexidine with respect to plaque and parameters of gingival inflammation: a systematic review. J Periodontol. 2011;82:174–194.
18. Kalemba D, Kunicka A. Antibacterial and antifungal properties of essential oils. Curr Med Chem. 2003;10:813–829.
19. Samuels N, Grbic JT, Saffer AJ, Wexler ID, Williams RC. Effect of an herbal mouth rinse in preventing periodontal inflammation in an experimental gingivitis model: a pilot study. Compend Contin Educ Dent. 2012;33:204–211.
20. De Nardo R, Chiappe V, Gómez M, Romanelli H, Slots J. Effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingival inflammation. Int Dent J. 2012;62:208–212.
21. Gonzalez S, Cohen CL, Galván M, Alonaizan FA, Rich SK, Slots J. Gingival bleeding on probing: relationship to change in periodontal pocket depth and effect of sodium hypochlorite oral rinse. J Periodontal Res. 2015;50:397–402.
22. Slots J. Low-cost periodontal therapy. Periodontol 2000. 2012:60:1110–1137.
23. Gbinigie O, Onakpoya I, Spencer E, McCall MacBain M, Heneghan C. Effect of oil pulling in promoting oro dental hygiene: A systematic review of randomized clinical trials. Complement Ther Med. 2016;26:47–54.

From Dimensions of Dental Hygiene. November 2016;14(11):29–30.