This common discoloration or special form of oral plaque is exclusively located on the tooth surface, especially on primary teeth, and caused by chromogenic bacteria. Insolvable iron sulphide gives a black colour to the, parallel to the gum line scalloped, running dots. The prevalence in children is about 4-8 per cent.
The chromogenic bacteria are mostly harmless and assumed to even be a protective factor for dental caries. Therefore, no treatment is indicated. For esthetic reasons there may be a professional cleaning every few month useful. Fast recurrences of black stain is common.