This article is based on an original article in Swedish which can be found here

BACKGROUND

Bad breath (halitosis) is described as an intense unpleasant odor beyond what is socially acceptable. Halitosis is a health issue that affects the social life of the individual concerned. A full 44% of respondents in a survey study believed that halitosis had a significant impact on their social life. Halitosis is classified into perceived (pseudohalitosis, halitophobia) or genuine halitosis. Pseudohalitosis means that the individual perceives bad breath, but this cannot be objectively measured or subjectively experienced by the examiner. Genuine halitosis is divided into physiological and pathological halitosis. Bad "morning breath" is often due to lower saliva secretion and less oral motor activity during sleep, which promotes bacterial growth and the breakdown/decay of food residues.

Bad breath is relatively common among both younger and older individuals and has been reported in the range of 15 to 55%, but it seems to increase with advancing age. Many are unaware of their bad breath as it is perceived as difficult to point out to someone that he/she has bad breath. Therefore, it is important for dental professionals to have knowledge of the causes of intra-oral halitosis and how to treat it. Daily, we as dental professionals comment on the patient's oral hygiene standards, but far more rarely on the patient's breath. For those with bad breath, it can develop into a significant social and psychological handicap.

What causes bad breath?

As previously mentioned, the oral cavity is the main cause of bad breath (intra-oral halitosis). Intra-oral halitosis is due to the breakdown of proteins from food residues, saliva, plaque, and epithelial cells by anaerobic bacteria. This breakdown results in the production of volatile sulfur-containing gases (VSCs) such as hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide ((CH3)2S). Hydrogen sulfide smells like rotten eggs, methyl mercaptan has a pungent odor of rotten cabbage, and dimethyl sulfide smells unpleasantly sweet.

Coated tongue, poor oral hygiene, gingivitis, mucositis, periodontitis, and peri-implantitis are significant for the occurrence of halitosis and explain 80-90% of intra-oral halitosis.

If the exhaled air from the nose smells bad, it is referred to as extra-oral halitosis. This can be caused by diseases of the airways (e.g., chronic diseases of the trachea or lungs, liver diseases, or diabetes). For dental professionals, it is important to distinguish between intra-oral and extra-oral halitosis. As dental professionals, we can help patients with intra-oral halitosis, but patients with extra-oral halitosis should be referred to an ear, nose, and throat specialist for further investigation.

Some individuals do not have bad breath but have a highly developed fear that they do (halitophobia). We, as dental professionals, can try in various ways to demonstrate that they do not have bad breath, which is difficult; otherwise, they may be referred for help from a psychologist.

DIAGNOSTICS

The method often used is the organoleptic method (smelling the patient's exhaled air). This is a subjective method but is considered the so-called "Gold standard." The procedure involves the patient closing their mouth for about a minute and then slowly exhaling the air present in the oral cavity (the patient should not exhale more air than what fits in the oral cavity). The distance between the person smelling the exhaled air (the examiner) and the person exhaling should be about 10 cm. The examiner then grades the degree of bad odor on a 6-point scale: 0) = no odor at all, 1) = weak scent but does not smell bad, 2) = weak odor classified as bad breath, 3) = definite bad breath, 4) = strong but tolerable odor, 5) = very strong odor that is not tolerated by the examiner. With a little training, anyone can learn to make such an assessment. To determine whether the odor comes from the oral cavity or the airways, one should smell both the air from the oral cavity and from the lungs. If the air that the patient exhales through the nose smells bad, it is classified as extra-oral halitosis.

A more precise recording of VSCs can be made with a portable gas chromatograph OralChroma™. This can provide accurate values of three different volatile sulfur compounds (hydrogen sulfide, methyl mercaptan, and dimethyl sulfide). However, this method is more suitable for research purposes than for use in general clinics.

Since coated tongue is a cause of bad breath, looking at the patient's tongue can provide some guidance on whether the patient can be expected to have bad breath or not. A simple index (Winkel Tongue Coating Index, WTCI) can be used. The tongue is divided into six fields, and the degree of coating on the different fields is assessed on a scale from 0 to 2 (0 = no coating, 1 = thinner whitish coating, 2 = thicker yellow/brown coating).

TREATMENT

Treatment of oral halitosis usually works very well. Treatment should always begin with addressing infections in the oral cavity such as gingivitis, periodontitis, mucositis, or peri-implantitis. Several studies have shown that this reduces the degree of bad breath, although the patient often may need some type of adjunctive treatment. If the patient has a lot of coating on the tongue, the use of a tongue scraper should also be recommended, as the surface of the tongue provides an environment where microorganisms can easily establish and multiply.

If the patient uses a tongue scraper and/or brushes their tongue, the tongue coatings decrease, which is good, but documentation on the effect of tongue cleaning on chronic halitosis is lacking. The patient should not overuse the tongue scraper, as it can cause increased keratinization of the tongue's papillae.

If the patient still has problems with intra-oral halitosis despite improved oral health, a mouth rinse based on zinc can be recommended as an adjunctive treatment. Zinc ions bind VSCs and therefore have the ability to reduce the degree of intra-oral halitosis. In addition to various zinc compounds, some products on the market also contain one or more antibacterial agents such as chlorhexidine or cetylpyridinium chloride. Products that contain a combination of zinc compounds and antimicrobial agents have reported a reduction in intra-oral halitosis in studies, although the scientific basis regarding their long-term effects is currently considered limited. However, in a 6-month study, patients who rinsed with a zinc/chlorhexidine-containing mouth rinse had significantly better control of intra-oral halitosis compared to individuals who used a placebo solution. We in dentistry should demand that manufacturers demonstrate that their products have proven effective not only in short-term trials over a few weeks but also in long-term treatment of intra-oral halitosis. This is because individuals who, despite treatment of periodontitis and use of a tongue scraper, still have intra-oral halitosis likely need long-term treatment with mouth rinses for bad breath.

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