The Power of Mouthrinses

Mouthrinses are chemotherapeutic agents used orally that, when combined with proper oral self-care, assist in the management of many dental conditions such as periodontal diseases, dental caries, xerostomia, and oral malodor. Some of these conditions significantly impact both oral and systemic health.¹

Multiple factors play a role in creating a favorable environment for oral diseases.¹ The chief etiologic factor for the most common oral diseases, such as caries and periodontal diseases, is the formation of pathogenic dental plaque-oral biofilm. Oral self-care, consisting of toothbrushing, interdental cleaning, and mouthrinsing, is key to maintaining optimal oral and overall health.^2,3 Evidence shows that an effective oral self-care regimen relies on mechanical methods of plaque removal and control.^4–7

Other parts of the mouth — such as interproximal areas of teeth, posterior regions of the mouth, gingival margin, and mucosa of the tongue, cheeks, and palate — often remain inadequately cleaned or untouched during self-care due to limited access or poor patient skill.^5,8 These areas account for 80% of the mouth’s surface area and harbor harmful bacteria that may cause disease and oral malodor.⁸ Mouthrinsing can help patients reach these areas, serving as an adjunct to mechanical methods of plaque removal.

Mouthrinse use is a practical, safe, and effective means to reinforcing positive oral health outcomes. It serves as a vehicle for the local delivery of therapeutic active ingredients to the oral cavity, especially those that are difficult to access. The effects of mouthrinses are enhanced when used in conjunction with mechanical methods of biofilm control, as mouthrinse delivery does not extend beyond 1 mm of the gingival margin. In addition, mouthrinses do not target mature biofilm associated with advanced forms of periodontal diseases.⁵

The ingredients found in mouthrinses can remain active for hours after their release and typically suppress, reduce, or kill the causal agents of oral diseases. Commercially marketed mouthrinses, available over the counter (OTC) or by prescription, are considered safe to use upon federal review by the United States Food and Drug Administration (FDA), which ensures their safety and efficacy (Table 1).

After receiving FDA approval, OTC oral rinses are eligible to apply for the American Dental Association Seal of Acceptance. To receive the seal, mouthrinses must submit clinical/laboratory data that support and substantiate the product’s safety and efficacy claims. The seal does not apply to prescription oral products.^5,8,9

Significant research has been conducted on the clinical benefits of specific active ingredients found in mouthrinses, demonstrating their ability to suppress the bacterial activity responsible for oral diseases.^2,8,10 Mouthrinses containing chlorhexidine gluconate (CHX), essential oils (EO), cetylpyridinium chloride (CPC), fluoride, and some natural compounds have all shown to improve conditions associated with dental plaque to some degree, particularly when combined with oral self-care.^2,5,8

Chlorhexidine Gluconate

Mouthrinses containing CHX have long been considered the gold standard for their highly efficacious bactericidal, bacteriostatic, and cariostatic properties.^4,5 In the US, CHX is available by prescription only and in concentrations of 0.1%, 0.12%, and 0.2%.^5,9

Classified as a cationic bisbiguanide, CHX’s positively charged molecules strongly adhere to the negatively charged surfaces of bacterial cell membranes.¹¹ This binding action causes leakage of bacterial intracellular components, inhibiting cell reproduction at low concentration and cell death with higher concentrations.⁵

CHX has a broad spectrum of antibacterial activity, making it effective against a host of microorganisms including those involved in the etiology of caries and periodontal diseases. CHX’s binding ability extends to the teeth, mucosa, pellicle, and saliva, allowing for continued release of its therapeutic effect for 8 to 12 hours once rinsing is complete.⁵

Studies using plaque, bleeding, and gingival indices over the course of 4 weeks to 6 months to measure the effectiveness of CHX in the treatment of mild to moderate cases of gingivitis found strong, high-quality evidence in support of CHX as a powerful anti-plaque and anti-gingivitis agent.^12,13 The most common therapeutic dosages and frequencies consist of rinsing with 10 to 15 mL of 0.1% to 0.2% CHX for 30 to 60 seconds twice daily, for patients with biofilm-induced periodontal diseases or oral mucositis, as well as patients undergoing periodontal or implant surgery.^8,9

The use of CHX is a standard recommendation in periodontal therapy and pre- and post-oral surgery when mechanical oral hygiene methods may be too difficult to perform due to pain and discomfort.^5,11 CHX’s use helps to reduce the risk of alveolar osteitis (dry socket).

CHX use does cause negative side effects such as staining of the teeth, tongue, and restorations; taste alteration; increased calculus formation; and burning sensation of the mouth.^4,5,14,11 Less commonly reported side effects include mucosal irritations, ulceration, soreness, desquamation, and parotid swelling.^5,12 These effects limit CHX to short-term use. CHX also binds to ingredients found in dentifrices, such as sodium lauryl sulfate, which can deactivate its therapeutic effect. Therefore, when using CHX, it is advisable to wait 30 minutes before or after brushing to prevent this interaction.

Essential Oils

Mouthrinses containing EO are among the most clinically studied oral antiseptic solutions due to their antimicrobial abilities.¹⁵ EO are OTC chemotherapeutic agents, belonging to a class of chemical compounds known as phenols.⁹ EO rinses typically contain a fixed formula of two phenolic compounds 0.064% thymol and 0.092% eucalyptol, mixed with 0.042% menthol and 0.060% methyl salicylate. Their mechanism of action is membrane disruption at high concentrations and the inactivation of essential enzymes at lower concentrations.

Through their mechanism of action, EO disrupt bacterial aggregation, retard bacterial multiplication, inhibit the maturation of plaque mass, and exhibit inflammatory properties. Research examining the use of EO with mechanical plaque control show that nearly half of users see reductions in plaque and gingival inflammation ranging from 16% to 60% when EO are added to self-care regimens vs mechanical plaque control methods alone.^5,9,15,16,   

EO and CHX mouthrinses have comparable efficacy; however, EO-containing rinses cause fewer side effects.^5,8 Rinsing with EO may have a sharp taste and cause mild burning that is relieved upon expectoration.^8,5,9 EO mouthrinses typically contain alcohol as a solvent to emulsify its ingredients, however, nonalcohol formulations are also available and show similar inhibiting effects on plaque regrowth as the alcohol-containing formulation, but a less inhibiting effect in comparison to a CHX control. Both EO (alcohol and nonalcohol-containing) and CHX mouthrinses show better inhibiting effects on plaque regrowth than placebos.¹⁷

Cetylpyridinium Chloride

Quaternary ammonium chemical compounds have antiseptic properties that prevent supragingival plaque formation and reduce the risk of gingivitis.^8,9,18 Of these quaternary ammonium chemical compounds, CPC is the most commonly used.^5,8,9,11,18 CPC’s mechanism of action relies on binding with the bacterial cell membrane. Its cationic nature causes a breakdown in the cell membrane, leading to intracellular loss of cell components, disruption of cell metabolism, and inhibition of cell growth that ultimately results in cell death.¹¹ CPC exerts bactericidal effects mainly on Gram-positive bacteria. Available in concentrations of 0.045% to 0.10%, CPC mouthrinse is used for the treatment of plaque-induced gingivitis.^5,11,18,19

Systematic reviews show CPC yields a small yet clinically significant anti-plaque and anti-gingivitis effect, particularly in concentrations equal to or greater than 0.05%.^5,8,11,18,19 Adverse effects similar to CHX, but to a lesser degree, have been documented with CPC.^5,11,20 Staining, taste alteration, and irritation or burning of oral mucosal tissue are the most commonly reported side effects.

Fluoride

Fluoride is a well-known caries-prevention agent used in a variety of OTC and professionally applied products. Systematic reviews show that fluoride mouthrinses prevent caries better than a placebo in permanent teeth among children and adolescents, as well in the prevention/arrest of root caries in older adults.^21,22

Fluoride mouthrinses typically range from 225 to 1,000 ppm and are intended for those ages 6 and older. In a study of adults, daily rinsing with 0.09% sodium fluoride significantly reduced crown and root caries over a 2-year period.²¹ These findings suggest that fluoride prevents caries among adults of all ages.

Fluoride supports the remineralization of early caries and inhibits demineralization. Remineralization involves the deposition of calcium phosphates from saliva to rebuild partly dissolved enamel crystallites. When fluoride is incorporated, the dissolution of these reinforced crystallites will be reduced during a subsequent sugar-induced and bacteria-mediated acid attack.²²

Herbal Rinses

Mouthrinses with all natural compounds and herbal ingredients offer oral health benefits as well. Mouthrinses with herbal and/or natural ingredients exhibit antibacterial and anti-inflammatory properties aiding in the control of dental biofilm and improved periodontal outcomes. Studies that have tested natural ingredients, such as aloe vera, tea tree oil, turmeric, clove, neem, and others, have found that, in some instances, the effects of these ingredients are comparable to EO and CHX with fewer side effects.^5,8,23–25 While this evidence is promising, many of the studies had limitations such as small sample sizes, short durations, and considerable heterogeneity.⁵ More research on natural compounds is necessary.

Conclusion

Mouthrinses are helpful adjuncts to mechanical biofilm control in preventing, reducing, and managing oral diseases.^2,5,8,10  Over the past 20 years, evidence has continued to demonstrate their safety and efficacy. Oral health professionals are responsible for remaining up to date on the scientific literature surrounding mouthrinses so they can provide informed recommendations.

References

1. Institute of Medicine and National Research Council. Improving Access to Oral Health Care for Vulnerable and Underserved Populations. Washington, DC: The National Academies Press; 2011.
2. American Dental Association. Mouthrinse. Available at: ada.org/resources/research/science-and-research-institute/oral-health-topics/mouthrinse-mouthwash. Accessed October 25, 2023.
3. American Dental Association. Home Oral Care. Available at: ada.org/resources/research/science-and-research-institute/oral-health-topics/home-care. Accessed October 25, 2023.
4. James P, Worthington HV, Parnell C, et al. Chlorhexidine mouthrinse as an adjunctive treatment for gingival health. Cochrane Database Syst Rev. 2017;3:CD008676.
5. Takenaka S, Sotozono M, Noiri Y. Evidence on the use of mouthwash for the control of supragingival biofilm and its potential adverse effects. Antibiotics (Basel). 2022;11:727.
6. Worthington HV, MacDonald L, Poklepovic Pericic T, et al. Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries. Cochrane Database Syst Rev. 2019;4:CD012018.
7. Fleming EB, Nguyen D, Afful J, Carroll MD, Woods PD. Prevalence of daily flossing among adults by selected risk factors for periodontal disease-United States, 2011-2014. J Periodontol. 2018;89:933–939.
8. Osso D, Kanani N. Antiseptic mouth rinses: An update on comparative effectiveness, risks, and recommendations. J Dent Hyg. 2013;87:10–18.
9. Darby ML, Walsh MM, Bowen DM, Pieren JA. Dental Hygiene: Theory and Practice. Philadelphia: Elsevier/Saunders; 2020.
10. Barnett ML. The rationale for the daily use of an antimicrobial mouthrinse. J Am Dent Assoc. 2006:137 Suppl:16S–21S.
11. Mouthwashes and Their Use in Dentistry: A Review. Available at: oralhealthgroup.com/features/mouthwashes-and-their-use-in-dentistry-a-review. Accessed October 25, 2023.
12. Gunsolley J. A meta-analysis of six-month studies of antiplaque and antigingivitis. J Am Dent Assoc. 2006;137:1649–1657.
13. Healthy People 2030. Objectives. Available at: health.gov/healthypeople/objectives-and-data/browse-objectives. Accessed October 25, 2023.
14. Chapple ILC, Mealey BL, Van Dyke TE, et al. Periodontal health and gingival diseases and conditions on an intact and a reduced periodontium: consensus report of workgroup 1 of the 2017 World Workshop on the classification of periodontal and peri-implant diseases and conditions. J Clin Periodontol. 2018;45 Suppl 20:S68–S77.
15. Haas AN, Wagner TP, Muniz FW, Fiorini T, Cavagni J, Celeste RK. Essential oils-containing mouthwashes for gingivitis and plaque: meta-analyses and meta-regression. J Dent. 2016:55:7–15.
16. 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.
17. Marchetti E, Tecco S, Caterini E, et al. Alcohol-free essential oils containing mouthrinse efficacy on three-day supragingival plaque regrowth: a randomized crossover clinical trial. Trials. 2017;18:154.
18. Haps S, Slot D, Berchier C, Van der Weijden G. 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.
19. Sreenivasan PK, Haraszthy VI, Zambon JJ. Antimicrobial efficacy of 0·05% cetylpyridinium chloride mouthrinses. Letters in applied microbiology. Lett Appl Microbiol. 2013;56:14–20.
20. Oo MM, Oo PH, Saddki N. Efficacy of 0.05% cetylpyridinium chloride mouthwash as an adjunct to toothbrushing compared with 0.12% chlorhexidine gluconate mouthwash in reducing dental plaque and gingival inflammation: a randomized control trial. Int J Dent Hyg. 2022;21:195–202.
21. Griffin SO, Regnier E, Griffin PM, Huntley V. Effectiveness of fluoride in preventing caries in adults. J Dent Res. 2007;86:410–415.
22. ten Cate JM. Contemporary perspective on the use of fluoride products in caries prevention. Br Dent J. 2013;214:161–167.
23. Kothiwale SV, Patwardhan V, Gandhi M, Sohoni R, Kumar A. A comparative study of antiplaque and antigingivitis effects of herbal mouthrinse containing tea tree oil, clove, and Basil with commercially available essential oil mouthrinse. J Indian Soc Periodontol. 2014;18:316–320.
24. Safiaghdam H, Oveissi V, Farzaei MH, Rahimi R. Medicinal plants for gingivitis: a review of clinical trials. Iran J Basic Med Sci. 2018 Oct;21:978–991.
25. Ajmera N, Chatterjee A, Goyal V. Aloe vera: it’s effect on gingivitis. J Indian Soc Periodontol. 2013;17:435–438.

From Dimensions in Dental Hygiene. November/December 2023; 21(10):16-18.