Читать книгу Basic Guide to Oral Health Education and Promotion - Alison Chapman - Страница 83

Supragingival calculus (Figure 2.4) begins to form after 2–14 days of inadequate plaque removal, depending upon the individual’s cleaning ability and mineral content of their saliva. Most supragingival calculus is found on teeth adjacent to the main saliva ducts, i.e. behind the lower central incisors and on the buccal (cheek) surfaces of the upper first and second molars.

Figure 2.4 Supragingival calculus before (right) and after (left) scaling.

Source: Mary Mowbray. Reproduced with permission of Mary Mowbray.

Supragingival calculus is usually preceded by plaque accumulation that becomes hardened (calcified) by the mineral salts in saliva (i.e. calcium and phosphate salts become incorporated into sticky plaque, causing calcification).

Some patients have more supragingival calculus than others, and this is because they:

 Have relatively more calcium and phosphate ions in saliva, and/or

 Do not remove plaque effectively, and so there is a material present for saliva to calcify.

 Have highly alkaline saliva, which favours the production of calculus.

Patients cannot remove calculus with a brush or floss once it has hardened, and because it has a rough texture, more plaque adheres, and the process of calcification begins again. Dentists and hygienists scale and polish teeth to remove supragingival calculus (and help prevent periodontal disease).