Halitosis, otherwise known as fetor oris, oral malodor or simply bad breath, is universally considered to be a socially unacceptable condition.84 Although prevalence estimates vary, it is clear that the condition affects a significant portion of the population, with an estimated 20-30% of adults reported to suffer from chronic breath malodor.84-90 Although a limited percentage of halitosis cases result from extraoral factors, such as diabetes, liver, kidney and other metabolic diseases,91 the highest percentage of cases are the result of intraoral causes,92 and are characterized by the production of gaseous volatile sulfur compounds (VSCs) associated with unpleasant bad breath.93,94 Hydrogen sulfide, methyl mercaptan and dimethyl sulfide are frequently cited as exhaled VSCs most commonly associated with unpleasant breath.92,95
Certain foods, especially ones like garlic and onions that contain pungent oils, can contribute to bad breath because the oils from these foods are eventually carried to your lungs and exhaled through your breath. Another source of bad breath can be individuals that experience ongoing sinus conditions, as sinus conditions can lead to a dry mouth. People with sinus conditions often have congested nasal passages and therefore need to breathe through their mouth. The drying effect of mouth breathing can create an environment that promotes bad breath. Additionally, sinus sufferers are likely to be taking antihistamines, a type of medicine that is known to create mouth dryness.
Even people who don't have an ongoing problem with bad breath easily notice that their breath is least pleasant in the morning when they first wake up. During the night, a person's salivary flow is reduced when a person sleeps. Saliva flow helps maintain mouth moisture, and it helps cleanse debris, bacteria and bacterial by-products that cause bad breath every time we swallow. As that effect is reduced overnight when we sleep, the result can be stale breath in the morning; a condition that is similarly noticed by people whose mouth becomes dry after speaking for long periods of time. Smoking is also considered to be a major cause of bad breath.
In the majority of cases, bad breath is caused by the presence of oral bacteria and oral debris.96 The bacteria and oral debris associated with breath malodor are largely found on the tongue as well as in subgingival and interproximal niches that are difficult to clean.97-99 In the absence of regular, thorough brushing and flossing, bacteria can accumulate on the bits of food left between the teeth, in the mouth and on the tongue. Sulfur compounds released by these bacteria give breath an unpleasant smell; with halitosis occurring when the unpleasant odor is then expelled from the mouth when exhaling. In addition to halitosis being an undesirable condition to have, it clearly has the potential to make social situations particularly unbearable.
Oral inflammatory diseases such as gingivitis and periodontitis are also associated with halitosis; a result of bacteria hiding in diseased tissues, producing foul gases.100,101 While meticulous oral hygiene in conjunction with scrupulous tongue brushing could theoretically help prevent persistent malodor, studies and surveys have shown that few adults regularly remove enough dental plaque through mechanical oral hygiene alone to alleviate the problem.102,103 In most cases, good professional oral care combined with a daily regimen of oral hygiene, including interdental cleaning, deep tongue cleaning and optional use of efficacious oral care products specially formulated to combat the germs that can cause bad breath, will lead to improvement.
Flavors to freshen breath. Bad breath sufferers often seek out help in the form of commercial products marketed to freshen objectionable breath. While some of these products are able to deliver a brief masking of the halitosis, most do not have the potential to provide long-term benefits. They are designed simply to temporarily mask odors. Unfortunately, many are quickly washed away by the natural flow of saliva. Methods used to help reduce bad breath, such as mints, mouth sprays, mouthwash or gum, may only temporarily mask the odors created by the bacteria on the tongue. These methods, however, cannot cure bad breath because they do not remove the source of the bad breath.
Antibacterial agents to reduce malodor. Antibacterial approaches can provide substantially longer-term breath efficacy than that provided by odor masking agents.104-106 As opposed to flavor agents that simply mask odor, antibacterial agents actually treat the source of the problem by targeting the malodor producing bacteria.
The use of zinc and triclosan are two dentifrice ingredients that have been identified for their ability to target bacteria and help reduce volatile compounds responsible for bad breath.107,108 Stannous fluoride, a well-studied antimicrobial agent with concurrent anticaries,68 desensitizing56,70 and anti-plaque and gingivitis benefits47,69 has been found to be a particularly effective as a dentifrice ingredient compared to other approaches for its ability to provide both germ kill and breath protection.109
Video 12. Formation of volatile sulfur compounds (VSC) by bacteria on tongue.
Video 13. Antibacterial agent reducing bacteria and VSC.