Halitosis: the tongue dorsum produces more sulphur compounds than the rest of the mouth

In the great majority of cases halitosis originates in the oral cavity, and the site contributing most is the dorsum of the tongue.

The reason is anatomical. The posterior tongue dorsum has an irregular surface with papillae and grooves offering an enormous adhesion area and a low-oxygen environment.

It is exactly what anaerobic gram-negative bacteria require, as they degrade proteins and produce the volatile sulphur compounds responsible for the odour.

It follows that cleaning teeth and gums without touching the tongue leaves the principal source intact, which is why patients with good dental hygiene can have persistent halitosis.

The right instrument is a scraper, and the difference from a toothbrush is not one of convenience. The scraper removes the coating by dragging it; the brush redistributes it among the papillae.

Filaments do not reach the base of the grooves and push material sideways, which explains why brushing the tongue gives poorer results than scraping it.

Correct technique starts as far back as possible and pulls forward in single passes, rinsing the instrument between them.

Pressure should be light. Scraping hard irritates the papillae and produces discomfort leading to abandonment, without removing more material.

The practical limit is the gag reflex, easier to trigger at the back. Ground is gained gradually: a few extra millimetres each week is better tolerated than an aggressive attempt that discourages.

Mouthwashes with zinc compounds or cetylpyridinium chloride act by binding sulphur compounds or reducing bacterial load, and are a useful adjunct.

They do not, however, replace mechanical removal, for the same reason a mouthwash does not replace a toothbrush: the coating remains and reproduces what the mouthwash neutralised.

If halitosis persists after a period of correct tongue hygiene, the origin should be sought elsewhere: periodontal pockets, defective restorations, ear-nose-throat conditions or reflux.

In summary: the posterior tongue dorsum is the principal site, a scraper removes where a brush redistributes, technique starts at the back with light pressure, mouthwashes are adjunct rather than substitute, and persistence after correct hygiene indicates a different origin.