From roughly 7 years old thereafter, most childrens permanent teeth would have undergone complete development (except their wisdom teeth), and therefore their susceptibility to fluorosis is greatly reduced, or even insignificant, despite the amount of intake of fluoride. The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, weight, degree of physical activity, nutrition, and bone growth. Individual susceptibility to fluorosis is also influenced by genetic factors.Many well-known sources of fluoride may contribute to overexposure including dentifrice/fluoridated mouthrinse (which young children may swallow), excessive ingestion of fluoride toothpaste, bottled waters which are not tested for their fluoride content, inappropriate use of fluoride supplements, ingestion of foods especially imported from other countries, and public water fluoridation. The last of these sources is directly or indirectly responsible for 40% of all fluorosis, but the resulting effect due to water fluoridation is largely and typically aesthetic. Severe cases can be caused by exposure to water that is naturally fluoridated to levels above the recommended levels, or by exposure to other fluoride sources such as brick tea or pollution from high fluoride coal.Dental fluorosis has been growing in the United States concurrent with fluoridation of municipal water supplies, although disproportionately by race. A 2010 CDC report acknowledges an overall incidence of dental fluorosis of 22% from 1986-87 increased to 41% in the early 21st century, with an increase in moderate to severe dental fluorosis from 1% to 4%.
This hypomineralized enamel has altered optical properties and appears opaque and lusterless relative to normal enamel.Traditionally severe fluorosis has been described as enamel hypoplasia, however, hypoplasia does not occur as a result of fluorosis. The pits, bands, and loss of areas of enamel seen in severe fluorosis are the result of damage to the severely hypomineralized, brittle and fragile enamel which occurs after they erupt into the mouth.Hydroxyapatite is converted to fluoroapatite in a three step process. Dental fluorosis can be prevented at a population level through defluoridation. It is the downward adjustment of the level of fluoride in drinking water. Management
Dental fluorosis may or may not be of cosmetic concern. In some cases, there may be varying degrees of negative psychosocial effects. The treatment options are:

Mild cases: Tooth bleaching
Moderate cases: Enamel microabrasion (outer affected layer of enamel is abraded in an acidic environment)
Severe cases: Composite fillings, Micro-abrasion, Veneers, Crowns

Epidemiology
Fluorosis is extremely common, with 41% of adolescents having definite fluorosis, and another 20% "questionably" having fluorosis according to the Centers for Disease Control. As of 2005 surveys conducted by the National Institute of Dental and Craniofacial Research in the USA between 1986 and 1987 and by the Center of Disease Control between 1999 and 2004 are the only national sources of data concerning the prevalence of dental fluorosis. Before the 1999-2004 study was published, CDC published an interim report covering data from 1999 to 2002.