A 19-year-old young man complains of cosmetic defect of all his teeth, which developed immediately after the teeth eruption. Objectively on the vestibular and masticatory surfaces of all patient’s teeth there are enamel defects, tooth crowns present with dark brown discoloration. Percussion and probing are painful. In this area ?uoride levels in water are 2.6 mg/L. Make the provisional diagnosis: