Mouthwash | Rinsing out your mouth after brushing

Bittner Dental Clinic

Key Points

  • There are two main types of mouthwash: cosmetic and therapeutic.
  • Therapeutic mouthwashes are available both over-the-counter and by prescription, depending on the formulation.
  • There are therapeutic mouthwashes that help reduce or control plaque, gingivitis, bad breath, and tooth decay.
  • Children younger than the age of 6 should not use mouthwash, unless directed by a dentist, because they may swallow large amounts of the liquid inadvertently.
  • A company earns the ADA Seal of Approval by providing scientific evidence that demonstrates the safety and efficacy of its product, which the ADA Council on Scientific Affairs carefully evaluates according to objective requirements.

Introduction

While not a replacement for daily brushing and flossing, use of mouthwash (also called mouthrinse) may be a helpful addition to the daily oral hygiene routine for some people.  Like interdental cleaners, mouthwash offers the benefit of reaching areas not easily accessed by a toothbrush.  The question of whether to rinse before or after brushing may depend on personal preference; however, to maximize benefit from the oral care products used, manufacturers may recommend a specific order for their use, depending on ingredients.  For example, some dentifrice ingredients (like calcium hydroxide or aluminum hydroxide) can form a complex with fluoride ions and reduce a mouthwash’s effectiveness. Therefore, vigorous rinsing with water may be recommended after brushing and before rinsing if these ingredients are present.1

Mouthwash is not recommended for children younger than 6 years of age.  Swallowing reflexes may not be well developed in children this young, and they may swallow large amounts of the mouthwash, which can trigger adverse events—like nausea, vomiting, and intoxication (due to the alcohol content in some rinses).1, 2 Check the product label for specific precautions and age recommendations.

Types of Mouthwash

Broadly speaking, there are two types of mouthwash: cosmetic and therapeutic.  Cosmetic mouthwash may temporarily control bad breath and leave behind a pleasant taste, but have no chemical or biological application beyond their temporary benefit.  For example, if a product doesn’t kill bacteria associated with bad breath, then its benefit is considered to be solely cosmetic.  Therapeutic mouthwash, by contrast, has active ingredients intended to help control or reduce conditions like bad breath, gingivitis, plaque, and tooth decay.

Active ingredients that may be used in therapeutic mouthwash include:

  • cetylpyridinium chloride;
  • chlorhexidine;
  • essential oils;
  • fluoride;
  • peroxide.

Cetylpyridinium chloride may be added to reduce bad breath.3  Both chlorhexidine and essential oils can be used to help control plaque and gingivitis.4, 5 Fluoride is a proven agent in helping to prevent decay.6 Peroxide is present in several whitening mouthwashes. Therapeutic mouthwash is available both over-the-counter and by prescription, depending on the formulation.  For example, mouthwashes containing essential oils are available in stores, while those containing chlorhexidine are available only by prescription.

Clinical Considerations

Some of the conditions mouthwashes are designed to address are discussed in the following sections.

Alveolar Osteitis (Dry Socket)

Alveolar osteitis (AO), also known as dry socket, is a common postoperative condition following dental extraction procedures, particularly those of the third molar.7 AO occurs when the fibrin clot that forms following extraction is dislodged; while the underlying cause is unclear, it is theorized that bacteria cause clot decomposition, compromising its stability. AO usually results in intense pain in and around the extraction site 2 to 3 days after the procedure. A recent systematic review and meta-analysis of 18 trials7 has shown chlorhexidine, without the use of antibiotics, to be effective for AO prevention following third molar extractions.  A moderate, but statistically not significant, increase in efficacy was seen in the gel formulation compared with the rinse formulation; however, the review could not recommend a specific dosing regimen. Studies included in the review reported minor, nonclinical reactions to chlorhexidine, including staining of teeth, dentures, and tongue, and altered taste.

Oral Malodor (Bad Breath)

Volatile sulfur compounds (VSCs) are the major contributing factor to oral malodor or bad breath.  They arise from a variety of sources (e.g., breakdown of food, dental plaque and bacteria associated with oral disease).3 Cosmetic mouthwashes can temporarily mask bad breath and provide a pleasing flavor, but do not have an effect on bacteria or VSCs.  Mouthwashes with therapeutic agents like antimicrobials, however, may be effective for more long-term control of bad breath.  Antimicrobials in mouthwash formulations include chlorhexidine, chlorine dioxide, cetylpyridinium chloride, and essential oils (e.g., eucalyptol, menthol, thymol, and methyl salicylate).  Other agents used in mouthwashes to inhibit odor-causing compounds include zinc salts, ketone, terpene, and ionone.1 Although the combination of chlorhexidine and cetylpyridinium chloride plus zinc lactate has been shown to significantly reduce bad breath, it also may significantly contribute to tooth staining.3, 8

Plaque and Gingivitis

When used in mouthwashes, antimicrobial ingredients like cetylpyridinium, chlorhexidine, and essential oils have been shown to reduce plaque and gingivitis when combined with daily brushing and flossing.5, 9 While some studies have found that chlorhexidine achieved better plaque control than essential oils, no difference was observed with respect to gingivitis control. Cetylpyridinium and chlorhexidine may cause brown staining of teeth, tongue, and/or restorations.4

Tooth Decay

Fluoride ions, which promote remineralization, may be provided by certain mouthwashes. A Cochrane systematic review found that regular use of fluoride mouthwash reduced tooth decay in children, regardless of exposure to other sources of fluoride (i.e., fluoridated water or toothpaste containing fluoride).10

Topical Pain Relief

Mouthwashes that offer pain relief most commonly contain topical local anesthetics such as lidocaine, benzocaine/butamin/tetracaine hydrochloride, dyclonine hydrochloride, or phenol.1  In addition, sodium hyaluronate, polyvinylpyrrolidine and glycyrrhetinic acid may act as a barrier to relieve pain secondary to oral lesions, like aphthous ulcers.1

Whitening

Mouthwash may contribute to extrinsic stain reduction when either carbamide peroxide or hydrogen peroxide are among the active ingredients.  Products that rely on carbamide peroxide typically contain 10 percent carbamide peroxide and may be dispensed by dentists to their patients for use at home.11  Mouthwashes that claim to whiten teeth also may contain 1.5 to 2 percent hydrogen peroxide.One study found that 12 weeks’ use of mouthwash containing hydrogen peroxide in this concentration range achieved similar color alteration as that achieved by 2 weeks’ use of 10 percent carbamide peroxide whitening gel.12

Xerostomia

Xerostomia is a reduction in the amount of saliva bathing the oral mucous membranes.  Since the lack of saliva increases the risk of caries, a fluoride-containing mouthwash may be helpful to those managing this problem.  However, since alcohol can be drying, it may be prudent to recommend an alcohol-free mouthwash.13 Mouthwashes containing enzymes, cellulose derivatives and/or animal mucins can mimic the composition and feel of saliva and may provide additional relief from symptoms associated with xerostomia.1

Oral Cancer Concern

Alcohol consumption as well as alcohol and tobacco use are known risk factors for head and neck cancers.14 Resulting from this has been the question of whether use of alcohol-containing mouthwash increases risk of these cancers.15 A recent systematic review and meta-analysis failed to find an association between mouthwash use and oral cancer, use of alcohol-containing mouthwash and oral cancer, or mouthwash dose response and oral cancer.16