Clinical and dental aspects of halitosis

Professor Crispian Scully

CBE, MD, PhD, MDS, MRCS, FDSRCS, FDSRCPS, FFDRCSI, FDSRCSE, FRCPath, FMedSci, FHEA, DSc, DChD, DMed(HC)

UCL Eastman Dental Institute, London,

Oral malodour or halitosis (Latin halitus = breath) describes any disagreeable breath odour. Genuine halitosis is where breath malodour is verified objectively. Pseudo-halitosis is where objective evidence of malodour is absent. Where patients persist in believing they have halitosis despite firm evidence for absence of objective evidence of malodour, the term halitophobia is used.
Malodour originates from the mouth, mainly from poor oral hygiene, ulcers or infections, in about 85% of patients affected. The odiferous products responsible appear to be (partly) produced endogenously and/or in the mouth and usually arise from microbial action involving a range of micro-organisms. They include volatile sulphur compounds - VSCs (such as hydrogen sulphide, methylmercaptan)- indoles such as indole and skatole, and polyamines (putrescine and cadaverine). Short chain fatty acids (e.g. valerate, propionate and butyrate) may also arise. Acetone, 2-butanone, 2-pentanone and 1-propanol may appear in both mouth and alveolar (lung) air, with indole and dimethyl selenide in alveolar air.
Halitosis is much less frequently associated with extra-oral causes (e.g. respiratory, gastrointestinal, drugs, metabolic).
Assessment is usually based upon organoleptic assessment of exhaled air - the clinician sniffs air exhaled from the mouth and nose – most apparently objective measurements of halitosis are expensive and time-consuming.
Smoking, drugs, and foods that might be responsible for malodour should be avoided. Regular meals are important. In most patients, treatment is directed towards reducing the accumulation of food debris and malodour-producing oral bacteria, achieved by treating oral/dental diseases, improving oral hygiene - tooth cleaning (brushing and interdental flossing) and use of antimicrobial toothpastes and/or mouthwashes (chlorhexidine gluconate, ceptylpyridinium chloride, zinc or triclosan, may be beneficial), by stimulating salivation (chewing gum), and reducing the tongue coating by brushing/scraping.