Dental decay, incidence

The problem of dental decay is certainly a formidable one and can only be mentioned in passing here. Local factors may be of primary importance, but the role of the resistance of the tooth should not be minimized. May Mellanby saw some decrease in the incidence of caries... 

Indirect evidence of a pre-emptive effect has been described by Sognnaes and by Toverud as a result of considerations of the caries incidence among children in European countries during and subsequent to World War II (99). The consumption of purified carbohydrates was greatly reduced during the war period and increased subsequently. However, changes in the rate of dental decay required several years to become apparent and appeared to be correlated with the time of mineralization of the developing teeth. 

While water fluoridation may be the most effective public health measure for inhibiting dental decay it would, at the same time, seem obvious that much more should be done to discourage the consumption of refined sugar which is so largely responsible for the high incidence of the disease in Western societies (page 133). 

Certain other agents such as hexachlorophene, silver nitrate, chlorophyll are also used to clean debris and decaying material and incidence of dental caries. 

The fluoride ion can exchange for hydroxyl in the crystal structure of apatite, a main component of skeletal bone and teeth. This stabilizes the regenerating tooth surface. Fluoride is available from saliva and may also be released from dental plaque at low pH. Initially, benefit was considered solely to be for the erupting teeth of children, but topical effects on adult teeth are now also thought to reduce decay. There is some initial evidence from small studies that pharmacological doses of fluoride may reduce the incidence of bone fracture in patients with osteoporosis. However, a metaanalysis of fluoride therapy from 11 controlled studies on 1429 subjects found that although this increased lumbar bone density, the incidence of vertebral fractures was not significantly decreased. ... 

The fluoride ion, at proper levels of intake, assists in the prevention of dental caries. When children under 9 years of age consume drinking water containing 1 part per million of fluorine, the teeth have fewer dental caries in childhood, adolescence, and throughout life. This has led to the fluoridation of water supplies in many countries. Fluoridation of water supplies to bring the concentration of fluoride to 1 ppm (one part of fluorine to a million parts of water) has proved to be safe, economical, and an efficient way to reduce tooth decay—a highly important public health measure in areas where natural water supplies do not contain this amount. Extensive medical and public health studies have clearly demonstrated the safety and nutritional advantages that result from fluoridation of water supplies. In communities in which fluoridation has been introduced, the incidence of tooth decay in children has been decreased by 50% or more. 

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