What condition is suspected when a 6-year-old child presents with black lines on the teeth at the gum line?

When a 6-year-old child presents with black lines on the teeth at the gum line, lead poisoning is suspected. This condition is associated with the appearance of lead lines, also known as Burton's lines, which manifest as a dark pigmentation caused by the deposition of lead in the enamel and dentin of teeth. Lead exposure can occur through various means, such as ingestion of lead-based paint or contaminated water, and it can have significant neurological and developmental implications for children.

The appearance of black lines specifically at the gum line is indicative of chronic exposure to lead rather than acute toxicity, as acute lead poisoning presents with more severe systemic symptoms. It is crucial to identify and address lead exposure early to prevent further health issues.

Other conditions listed do not typically present with this specific dental manifestation. For example, Perthes disease is a hip disorder affecting the blood supply to the femoral head, and does not affect dental health. Salicylate toxicity, commonly related to aspirin overdose, may lead to gastrointestinal distress or metabolic complications but does not cause discoloration of teeth. Tetracycline administration can lead to intrinsic staining of teeth, but these stains usually appear yellow or brown rather than black and do not specifically localize to the gum line as seen in lead