Supragingival calculus and periodontal disease.

Supragingival calculus predisposes to the development of periodontal disease by providing a retentive surface for plaque bacteria and impeding attempts to maintain an effective level of plaque control (47). Although the presence of calculus and gingival inflammation, as evidenced by bleeding on probing, are not always coincident (1) the close proximity of supragingival calculus to the gingiva ensures that its superficial layer of plaque bacteria is maintained in contact with the gingival tissues. The finding that oral hygiene instruction alone resulted in significant improvements in the gingival health of individuals with large amounts of calculus supports the primary role of plaque bacteria (21). Recent studies have investigated the relationship between supragingival calculus and gingival recession (59). A selected sample of Thai children and adolescents were examined, and the amount of supragingival calculus and gingival recession was measured on the six lower anterior teeth. A significant association was observed between total calculus levels and the presence and extent of gingival recession. Two clinical studies, again involving Thai children and adolescents, demonstrated that subjects who used an anticalculus dentifrice for 1 year had significantly less supragingival calculus and gingival recession than those who used a placebo dentifrice or continued to use their customary oral hygiene procedures (60, 81). Supragingival calculus is relatively porous and becomes stained by dietary constituents and tobacco, and its removal is generally appreciated by the individual. Although toothbrushing with a conventional toothpaste containing abrasives and detergents may interfere with its formation, the widespread prevalence of supragingival calculus clearly indicates that such measures are not generally very effective. The dental profession spends a considerable amount of time removing supragingival calculus. In England and Wales periodontal treatment comprises approximately 23% of the treatment provided by the National Health Service (NHS) general dental services. In 1988-1989, single-visit scale and polishes cost GBP 120 million, approximately 12% of the total costs. The professional removal of supragingival calculus is frequently undertaken as part of a more comprehensive program to remove tooth deposits and provide instruction and advice regarding the maintenance of effective oral hygiene. Many factors influence how often supragingival calculus is removed, including the rate of supragingival calculus formation and whether the costs are borne by the patient or some other form of health care system. The implications of scaling and polishing have been considered in a previous review (2). Since supragingival calculus is a predisposing factor in the development of gingivitis and recession the development of clinically proven products that reduce its formation benefits both the profession and consumers. Anticalculus products comprise a significant sector of the oral hygiene market in many countries. For example, in the United States, anticalculus toothpaste accounted for approximately one quarter of total toothpaste sales in 1995.