What causes the mottling of the dental enamel ?

Mottling of dental enamel is primarily caused by high levels of fluoride in drinking water, a condition known as dental fluorosis. While low levels of fluoride are beneficial for preventing tooth decay by strengthening enamel, excessive intake during the formative period of permanent teeth (typically before age 8 or 9) leads to discoloration, pitting, and the appearance of white flecks or opaque marks [t1, t3, t4]. Specifically, fluoride concentrations exceeding 0.3 ppm have been associated with teeth mottling, and levels above 5 mg/l are significantly detrimental to tooth structure [t2, t10]. In severe cases, this excess fluoride can also lead to skeletal fluorosis, causing stiff joints and bone deformities [c1, c2]. Other substances like nitrates are associated with 'blue baby syndrome' rather than dental issues [t3, t7].

Sources

1. [1] https://www.cdc.gov/oral-health/about/about-dental-fluorosis.html
2. [2] https://www.epa.gov/privatewells/potential-well-water-contaminants-and-their-impacts
3. [3] https://pmc.ncbi.nlm.nih.gov/articles/PMC3956646/
4. [4] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > ag.l.s.Fluorine > p. 414
5. [5] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 3. Hazards of ground water pollution: > p. 76