A reduction in irregular deposits of calcium salts in either teeth or bone. Teeth with fluorosis exhibit a sub-surface hypomineralization of the enamel. Molar incisor hypomineralization (MIH) is the developmental hypomineralization of one or more permanent first molars associated with hypomineralization of the permanent incisors; the cause is unclear. The appearance can range from mild enamel opacities to enamel that is easily abraded on tooth eruption causing extensive hypersensitivity and often resulting in extensive carious lesions. Management is usually by sealants, restorative intervention, or extraction depending on the severity of the condition. See also hypoplasia; amelogenesis imperfecta.