ORAL MALODOUR
Halitosis (from the Latin for breath, Halitus) is a very common complaint among the general population and may
affect up to 30% of individuals.1 In recent years, this area has witnessed growing technology and communications
with particular increase in advertisements for bad breath remedies in the media. This, in turn, has raised the
levels of information and misinformation about bad breath among the patient population. I am sure that you are
commonly asked about the causes and treatment of halitosis so it is important that we educate our patients
correctly.
Halitosis has a complex aetiology with extrinsic and intrinsic pathways. Extrinsic causes include tobacco, alcohol
and specific food substances such as onion, garlic and certain spices2,3. Substances absorbed by the circulatory
system may be released in pulmonary air or saliva as volatile compounds derived from foods. Intrinsic causes of
bad breath are oral or systemic in origin. In general, approximately 90% of the cases are of intra-oral origin (oral
malodour), whereas only 10% of these cases are of systemic origin 4-6. Oral malodour is the result of the action of
anaerobic bacteria in producing a range of malodorous molecular species including volatile sulphur compounds.
Whilst malodour is often associated with the presence of periodontitis, in many cases there is no such link, and
the evidence points to the importance of these anaerobic bacteria in tongue coatings, which results in the clinical
presentation of oral malodour.
The initial contact with a patient may stem from a complaint of bad breath, either suspected by the patient or
identified by another person. However, a patient may be a very poor judge of his or her personal level of halitosis.
Many patients who complain of bad breath do not have malodour as determined organolepitcally7,8. There are
individuals who do not have halitosis but are convinced that they do; the term ‘halitophobia’ has been applied to
such patients9. Some of the latter may have a range of psychopathological symptoms that often complicate the
diagnosis and management of oral malodour. Contrastingly, some patients have oral malodour but may be
completely oblivious of it.
A thorough medical and dental history is necessary to determine the cause(s) of halitosis. Several systemic
conditions can exclusively or partially contribute; particular emphasis should be placed on medication history and
history of disease or injury to the upper face and sinuses. An intra-oral examination is imperative to reveal any
pathology of oral origin that may contribute to the halitosis as well as oral hygiene status and extent of mouth
breathing.
There is no ideal test to objectively assess the extent of oral malodour. However, direct tests and indirect tests
exist. Direct tests include sniffing of the bad breath. The human nose is an extremely sensitive sensor and is able
to detect more than 10000 different odours; it is the primary reference standard for breath analysis. Direct
sniffing of expired air is the simplest, most common method to evaluate oral malodour 10. Although this method
may be objectionable to the dentist, it is the one that most closely resembles daily situations in which oral
malodour is detected. Rosenberg et al introduced an organoleptic scale ranging from 0 to 5 (0 = no odour, 1 =
barely noticeable, 2 = slight but clearly noticeable odour, 3 = moderate odour, 4 = strong odour, 5 = extremely
foul odour) and this scale has been used in many studies 11-13. The organoleptic evaluation of oral malodour
depends on the operator and technique used. The technique can vary from whole mouth, nose assessment,
tongue odour test and saliva odour test. For whole mouth breath assessment, which is usually regarded as the
method of choice, the patient is instructed to breathe out through the mouth at a distance of 10 cm from the
nose of the blinded judge13,14. Another direct method is determination of the malodourous substances by
halimetry. A relatively inexpensive, portable industrial sulphide montiro, sold commercially as the Halimeter
(Interscan, Chatswoorth, Calif.) has been adapted to measure gases associated with oral malodour.14 This monitor
measures volatile sulphur compounds with an electrochemical sensor using a suction pump to bring mouth air
into the instrument. Some studies that used this monitor found significant correlations between the measures of
sulphide concentration obtained with the monitor and the organoleptic assessment of oral malodour.14
Indirect methods assess oral malodour potential either by identifying putative organisms that are believed to
produce volatile sulphur compounds in vivo or the by-products produced by these microorganisms in vitro. These
include bacterial culture, direct bacterial smears and enzyme assays.
So what are the solutions to this unpleasant condition? The first step in treating oral malodour is to treat any
disease or pathology existent in the mouth; this may include the treatment of periodontal disease. For diseasefree people, treatment is aimed at reducing microorganisms in the oral cavity that may be producing volatile
compounds. This can be accomplished by mechanical or chemical means. When considering mechanical cleaning,
emphasis should be placed on cleaning of the dorsum of the tongue; brushing the tongue decreases volatile
sulphur compounds by around 75%15. A number of tongue brushes and cleaners are now available. There is ample
evidence in the literature that brushing and flossing of teeth reduces the number of microorganisms in the oral
cavity, thereby reducing oral malodour16. Both professional and home oral hygiene procedures are important in
controlling oral malodour. Chemical control may be accomplished by a number of oral actives, including
antibacterial agents (essential oils, cetylpyridium chloride, chlorine dioxide, hydrogen peroxide, domiphen
bromide and others) and antimicrobial metabolics (zinc salts and others). Mouthwashes have been advertised for
the elimination of halitosis and this is often the primary reason why people use them. Though numerous industrysponsored studies have evaluated the effectiveness of oral malodour products, most of these studies are
unpublished or results are equivocal and proprietary. Recommendations of specific products can be made with
greater confidence when clinical results demonstrating safety and efficacy have been published. If the source of
the malodour is not in the oral cavity, the patient should be referred to their general practitioner for further
assessment.
In summary, assessing oral malodour vigilantly from the beginning will enable dental professionals to treat each
case appropriately. The increase in interest in oral malodour among dental professionals and the general public
should result in better understanding of the aetiology of the condition and the development of more effective
diagnostic and treatment methods. Simple and innovative products should help patients with oral malodour to
live comfortably and with self-confidence.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Hughes F, McNab R. Oral malodour- a review. Arch Oral Biol 2008; 53 Suppl 1:S1-7.
McDowell JD, Kassebaum DK. Diagnosing and treating halitosis. JADA 1993; 124: 55-64.
Scully C, el-Maaytah M, Porter SR, Greenman J. Breath Odour: aetiopathogenesis, assessment and management. Eur J Oral
Sci 1997; 105(4): 287-93.
Attia EL, Marshall KG. Halitosis. Can Med Assoc J 1982; 126: 1281-5.
Rosenberg M. Bad breath: diagnosis and treatment. Univ Toronto Dent J 1990; 3(2): 7-11.
Weinberg M. Halitosis: the ‘bad breath’ syndrome. US Pharmacist 2001; 26(3): 46-57.
Bosy A, Kulkarni GV, Rosenberg M, McCulloch CA. Relationship of oral malodour to periodontitis: evidence of
independence in discrete subpopulations. J Periodontol 1994; 65: 37-46.
Rosenberg M. Clinical assessment of bad breath: current concepts. JADA 1996; 127: 475-82.
Loesche WJ, Kazor C. Microbiology and treatment of halitosis. Periodontol 2000 2002; 28: 256-79.
Rosenberg M, McCulloch CA. Measurement of oral malodour: current methods and future prospects. J Periodontol 1992;
63: 776-82.
Rosenberg M, Gelernter I, Barki M, Bar-Ness R. Daylong reduction of oral malodour by a two-phase oil: water mouthrinse,
as compared to chlorhexidine and placebo rinses. J Periodontol 1992; 63: 39-43.
Amir E, Shimonov R, Rosenberg M. Halitosis in children. J Pediatric 1999; 134: 338-43.
Rosenberg M, Septon I, Eli I. Halitosis measurement by an industrial sulphide monitor. J Periodontol 1991: 62; 487-9.
Rosenberg M, Kulkarni V, Bosy A, McCulloch CA. Reproducibility and sensitivity of oral malodour measurement with
portable sulphide monitor. J Dent Res 1991; 11:1436-40.
Tonzetich J. Production and origin of oral malodour: a review of mechanisms and methods of analysis. J Periodontol 1977;
48: 13-20.
Rosenberg M. Clinical assessment of bad breath: current concepts. JADA 1996; 127: 475-82.