Tooth abnormalities caused by environmental factors during tooth development have long-lasting effects. Enamel and dentin do not regenerate after they mineralize initially. Enamel hypoplasia is a condition in which the amount of enamel formed is inadequate. This results either in pits and grooves in areas of the tooth or in widespread absence of enamel. Diffuse opacities of enamel does not affect the amount of enamel but changes its appearance. Affected enamel has a different translucency than the rest of the tooth. Demarcated opacities of enamel have sharp boundaries where the translucency decreases and manifest a white, cream, yellow, or brown color. All these may be caused by nutritional factors, an exanthematous disease (chicken pox, congenital syphilis), undiagnosed and untreated celiac disease, hypocalcemia, dental fluorosis, birth injury, preterm birth, infection or trauma from a deciduous tooth. Dental fluorosis is a condition which results from ingesting excessive amounts of fluoride and leads to teeth which are spotted, yellow, brown, black or sometimes pitted. In most cases, the enamel defects caused by celiac disease, which may be the only manifestation of this disease in the absence of any other symptoms or signs, are not recognized and mistakenly attributed to other causes, such as fluorosis. Enamel hypoplasia resulting from syphilis is frequently referred to as Hutchinson's teeth, which is considered one part of Hutchinson's triad. Turner's hypoplasia is a portion of missing or diminished enamel on a permanent tooth usually from a prior infection of a nearby primary tooth. Hypoplasia may also result from antineoplastic therapy.