Halitosis: in eighty per cent of cases the origin is the tongue dorsum

Halitosis is a complaint patients raise with embarrassment and which often receives a generic answer about hygiene. The causes are identifiable and in the great majority resolvable.

The compounds responsible for the odour are volatile sulphur compounds, produced by anaerobic bacteria degrading proteins. Hydrogen sulphide, methyl mercaptan and dimethyl sulphide are the principal ones.

The literature converges in attributing the great majority of cases to intraoral causes, and among these the tongue dorsum is the principal reservoir.

The reason is anatomical: the filiform papillae create an irregular surface that retains debris, desquamated cells and bacteria. It is an oxygen-poor environment, ideal for anaerobes.

From this follows the most effective and most neglected instruction: cleaning the tongue dorsum should be taught as part of the routine, not mentioned in passing.

A scraper is superior to a toothbrush for this purpose. It removes the coating with a dragging action rather than displacing it, and provokes less gagging because no pressure is needed.

A toothbrush used on the tongue tends to spread the material rather than collect it, and the head shape does not conform to the lingual surface.

The technique is simple and should be demonstrated: the scraper is placed as far back as tolerated without gagging, drawn forward with light pressure, rinsed and repeated several times.

The gag reflex diminishes over the first weeks through adaptation, and this should be mentioned in advance, or the patient abandons the practice after the first attempt.

Other intraoral causes must be excluded before attributing everything to the tongue: periodontitis, deep caries, overhanging restorations, unclean dentures, xerostomia. Each has its own treatment.

Dryness is a frequent and underestimated cause, and explains physiological morning halitosis: during sleep salivary flow falls and anaerobes proliferate.

Extraoral causes are a minority but they exist, and some are recognisable by odour. A fruity smell may indicate ketoacidosis, an ammoniacal one renal failure, a faecal one intestinal obstruction. These call for medical referral, not dental treatment.

In summary: most halitosis originates on the tongue dorsum, a scraper is more effective than a brush, the gag reflex fades with habit, and other oral causes must be excluded before concluding.