halitosis

halitosis, bad breath, or foetor oris (stench of the mouth) is an age-old and universal problem. Nowadays it is called oral malodour. But halitosis by any other name still smells as foul! Bad breath is mainly a social problem — a fact exploited by the cosmetics industry. Nearly 25 centuries ago, Hippocrates wrote that ‘a pleasant odour is essential in any girl, and can be obtained and maintained by using a mouthwash containing anise, dill seeds, myrrh and white wine’. The Roman dramatist, Maccius Plautus claimed that his wife's breath was so foul that he would ‘rather kiss a toad’.

Oral malodour is caused by nasty-smelling chemicals, such as hydrogen sulphide (H₂S) and methyl mercaptan (CH₃SH). These substances are by-products of protein breakdown by bacteria. In the case of oral malodour, these proteins are mostly derived from cells shed from the lining of the mouth. However, some cases may arise from dental plaque and from food debris trapped between the teeth.

In about 85% of cases, the malodour originates in the mouth. The commonest sources are the spaces between the teeth, around the gum margins, and at the back of the tongue. Dentures can sometimes be a cause, especially if these are not regularly cleaned. Malodours may also originate from the nose and throat. Unpleasant breath smells can occasionally occur after eating foods such as garlic, or in heavy smokers. Breath smells may arise from other organs, such as the gastrointestinal tract and lungs, or in metabolic disorders such as diabetes mellitus. But these are relatively rare causes of oral malodour.

People are not usually aware of the malodour. (A few people are obsessed about bad breath, even though their breath smells normal.) Just as beauty is in the eye of the beholder, so bad breath is in the nose of the receiver! In other words, we rely on others to tell us of any problem. This can be a source of embarrassment. Hieron of Syracuse allegedly reprimanded his wife for not informing him of his bad breath. She neatly avoided an awkward situation by replying innocently that she thought all men's breath must smell so foul!

People are unaware of their own breath, partly because senses adapt to a constant stimulus, but mainly because the air flow from the mouth does not enter the nose. We can detect malodours if we smell dental floss or woodsticks that have been used to clean between our teeth. Another way is to smell a spoon that has been scraped over the tongue surface. Devices are now available for detecting and measuring the chemicals responsible for malodour.

In most cases, the remedy is simple. Effective oral hygiene will remove the causative agents. This involves cleaning between the teeth and also brushing or scraping the surface of the tongue. Interestingly, the practice of tongue scraping was introduced in India many centuries ago. Mouthwashes can also be used, but are generally ineffective without the oral hygiene measures.

Robin Orchardson

Bibliography

Ratcliff, P. A. and and Johnson, P. W. (1999). The relationship between oral malodor, gingivitis and periodontitis. A review. Journal of Periodontology, 70, 485–89.
Rosenberg, M. (1996). Clinical assessment of bad breath: current concepts. Journal of the American Dental Association, 127, 475–82.