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Reducing the oral cavity's bacterial load is essential to maintaining health. Here's how antimicrobial mouthrinses can help. By Kathleen O. Hodges, RDH, MS


Antimicrobial mouthrinses can be an effective adjunct to self–care routines for patients experiencing a number of oral health problems, including gingivitis, caries, and enamel erosion. There is no shortage in selection when considering the best mouthrinse for individual patient needs. Antimicrobial rinses typically contain chlorhexidine gluconate, essential oils, cetylpyridium chloride, or stannous fluoride. By understanding the mechanism of action of these antimicrobials, dental hygienists will be well prepared to provide effective recommendations for their patients.



Chlorhexidine gluconate (CHX) mouthrinse has great substantivity, meaning it is retained in the oral cavity for extended periods of time and provides a slow and sustained release of the active ingredient. As a result, CHX mouthrinse is known the "gold standard" of mouthrinses.1–3 Research conducted in the 1980s found that CHX was the most effective agent against supragingival plaque and gingivitis, with reported plaque reductions of 50% to 55% and gingivitis reductions of 45%.1–3 In the United States, CHX commercial rinse preparations are available by prescription only in a 0.12% concentration with 11.6% alcohol and a pH of 5.5 to 6.0. It can also be compounded at a pharmacy where inactive ingredients may be adjusted. An alcohol-free version is also available that has been approved by the federal Food and Drug Administration (FDA) as therapeutically equivalent to traditional CHX rinses.4 

A lipophilic broad-spectrum antimicrobial agent, CHX disrupts cells osmotic equilibrium, which leads to cell death. CHX's pronounced substantivity results from its absorption into oral mucosa, hydroxyapatite, and salivary glycoprotein. Approximately 30% is retained in the oral cavity after rinsing, and it remains effective for 8 hours to 12 hours.5 FDA approval of CHX mouthrinse is limited to gingivitis, however, it is also used in the treatment of oral candidiasis, aphthous stomatitis, linear gingival erythema, necrotizing ulcerative periodontitis, and HIV/AIDS care.1–3 In addition, CHX helps prevent respiratory infections, reduces bacteria in the edentulous, and supports oral health in those undergoing chemotherapy.1–3 Evidence has not shown that CHX mouthrinse is effective in the treatment of periodontitis, however, the rinses's efficacy in reducing gingivitis may enhance prevention of chronic periodontitis.

Patients should not rinse, eat, or brush immediately after using a CHX mouthrinse to prevent the loss of substantivity.1–3 Patients should be advised of the rinse's side effects, including bitter taste, staining, increased calculus formation, and altered taste sensation. Modern CHX mouthrinses have improved taste through the addition of flavoring, and the calculus formation and staining can be controlled by effective self-care and professional treatment. Best used after meals to prevent interference with taste, patients should also wait at least 30 minutes after toothbrushing to prevent interaction between sodium lauryl sulfate and other elements in dentifrice.1–3 

Patients' insurance coverage for prescription medication should be considered when recommending CHX because ease of purchase and cost effectiveness both influence compliance. Over–the–counter (OTC) products may be a better choice when access and cost are factors.

Short–term CHX mouthrinse is also used to treat rampant caries and is recommended for those at high caries risk. Suggested use is typically to rinse with 10 ml daily for 1 week each month.6 However, a 2011 summary of evidence– based clinical recommendations concluded that CHX rinse is not effective in coronal or root caries prevention7. The effects of CHX, essential oils, and fluoride on three root caries pathogens were investigated in an artificial mouth model. CHX created the most significant inhibition results, as well as the best inhibitory action against Streptococcus mutans, Lactobacilli, and Candida albicans when compared to sodium fluoride.8 



Phenolic compounds, such as essential oils, reduce plaque and gingivitis. Essential oil mouthrinses usually contain a combination of thymol, eucalyptol, menthol, and menthyl salicyclate. Essential oils decrease plaque formation and bacterial adhesion. Side effects include burning, objectionable taste, and tooth staining. Chemical irritation and desquamative oral mucosa can occur with prolonged rinsing. The mouthrinse usually contains 21.6% to 26.95% alcohol at a pH of 5.0; nonalcohol compounds are available, however, they are not antiseptics. The antiseptic is contraindicated for alcoholics or recovering alcoholics (as are all rinses with alcohol; it is recommended that patients check with their abuse counselor9) and patients with oral cancer. While alcohol use is a risk factor for oral cancer, evidence has not demonstrated an increased risk of oral and pharyngeal cancers with the use of alcoholcontaining mouthrinses. Essential oil mouthrinses are often used when CHX mouth rinses are contraindicated due to taste, cost, esthetics, ease of purchase, or mode of application.



Cetylpyridium chloride (CPC) is a quarternary ammonia compound used at 0.05% or 0.07% with or without other ingredients, such as domiphen bromide. CPC's mechanism of action is similar to CHX's in that positive ions bind to the negatively charged cell wall— affecting permeability and loss of cellular contents. Long–term clinical results generally show that CPC is less effective than CHX and essential oils due to its lack of substantivity and rapid clearance from the oral cavity.10 Burning, soft tissue irritation, and slight staining have been cited as side effects. Alcohol content varies from 0% to 18% and the pH is 5.5 to 6.5.



Stannous fluoride rinses are another alternative. Pizzo et al11 evaluated the use of amine fluoride/stannous fluoride (ASF) and CHX on plaque regrowth and found that CHX was more effective, however, ASF had fewer side effects. The authors suggest that ASF might be a substitute for CHX mouthrinse when side effects are of concern. Stannous fluoride is also a proven caries prevention agent.



Delmopinol hydrochloride is not an antimicrobial but rather it inhibits bacterial adhesion to the tooth and mucosa, and cohesion between cells. As a result, the rinse improves the efficacy of patient removal of plaque biofilms, in addition to disrupting cariogenic and periodontal pathogens. The rinse contains 1.5% alcohol. Delmopinol mouthrinse is recommended as a precursor to CHX, as well as an appropriate addition to a self–care regimen after treatment with a CHX rinse is complete.12 



Gunsolley10 evaluated the efficacy of antiplaque, antigingivitis mouthrinses and the clinical relevance of the evidence. Three systematic reviews and one meta–analysis were found. Strong evidence supported the efficacy of CHX and essential oils as antiplaque, antigingivitis mouthrinses while the evidence for CPC was weaker due to few clinical trials testing the same formulations. One meta–analysis of delmopinol concluded it was an effective antiplaque, antigingivitis agent. Gunsolley et al concluded that the clinical effects of CHX and essential oil mouthrinses met or exceeded reductions over time when compared to placebo groups.

Studies have evaluated the effects of mouthrinses on other oral problems. In a systematic review on breath malodor, evidence showed that CHX was effective, as well as a CPC/zinc combination.13 A CHX/ CPC/ zinc lactate mouthrinse was effective in reducing breath malodor and both CHX and CPC were recognized as effective, although more randomized control trials containing additional subjects with longer intervals and follow–up periods are needed.13 ASF mouthrinse was compared to CHX rinse for malodor in a single use in vivo. ASF was found to be more effective.14 Eick et al15 studied the in vitro effect of CHX, essentials oils, and ASF against periodontopathic microorganisms and concluded all were active against the microbes, and that long–term use would not result in emergent antimicrobial resistance. Featherstone et al16 tested an intervention of a fluoride dentifrice (1,100 ppm NaF), 0.12% CHX rinse, and 0.5% NaF rinse and concluded that targeted antibacterial and fluoride therapy based on salivary microbial and fluoride levels altered caries risk factors for the better. A systematic review on Staphylococcus aureus in lower respiratory tract infections and cross infections to other patients concluded that CHX in mouthrinses, gels, and sprays had some effect, but more randomized controlled trials were needed.17 In a study on Streptococci and complete dentures, CHX showed the most antimicrobial action when compared to CPC and a nonantimicrobial rinse.18 



Antimicrobial mouthrinses are effective adjuncts to self–care regimens. The American Dental Association Seal of Acceptance provides added credibility to product claims, but is only available for OTC products. Oral health professionals need to target their recommendations to patient conditions and needs. Patients need to understand that antimicrobial mouthrinses are an addition to an appropriate self–care regimen and regular professional care. Antimicrobial mouthrinses can be especially effective among patients with poor self–care and those who need assistance reducing the bacterial load, which is key to both improving oral and systemic health.




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From Dimensions of Dental Hygiene. November 2012; 10(11): 23–24. 

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