A 26-year-old man presented with complaints of an unpleasant smile caused by generalized tooth discoloration. His medical history was non-contributory. The patient reported that the water in his area has high fluoride level (>3.6 mg/l). Clinical examination revealed changes in the morphology of teeth (Cover Image).

What is the most likely diagnosis? Source: Case Rep Dent. *This case is from the Docplexus Editorial Team for educative purposes only. The correct answer will be posted soon!