Investigations

In patients with halitosis

• detailed medical, dental and oral malodour history should be obtained – including medication history which might reveal an offending drug
• an intraoral examination – to find out any oral diseases which may contribute to bad breath (1)

The investigation of systemic diseases which cause halitosis is detailed under the relevant sections.

For a simple case of halitosis, an independent observer is usually a good judge of the degree of malodour. This method of directly smelling the expired air (from both mouth and nose) and comparing the two (the organoleptic method) is usually subjective and depends on the examiner and the technique used (1,2)

• odour from the mouth alone – cause is likely to be of oral or pharyngeal origin
• odour from the nose alone – cause is likely to from the nose or the sinuses
• odour from both nose and mouth in equal intensity – a systemic cause is likely (2)

In a specialist clinic the use of a portable sulphide monitor allows a quantitative assessment but it may not detect non-sulphide components responsible for oral malodour (2).

Reference:

• (1) ADA Council on Scientific Affairs. Oral malodour. J Am Dent Assoc. 2003;134(2):209-14
• (2) Porter S.R, Scully C. Oral malodour (halitosis). BMJ 2006;333(7569):632–635