A child presents with discoloration of teeth #8 and #9. The discoloration is due to which process?

Correct answer: B. Breakdown of red blood cells (hemoglobin degradation)

• A. INCORRECT. Fluorosis causes white/opaque spots or brown mottling on enamel surfaces. It results from excessive fluoride intake during tooth formation and would not explain isolated discoloration of specific teeth following trauma.
• B. CORRECT. Internal discoloration of teeth following trauma is caused by breakdown of red blood cells (RBCs) within the pulp chamber. Hemoglobin from lysed erythrocytes degrades into iron sulfide and other chromogenic byproducts that diffuse into dentinal tubules, causing the characteristic gray, pink, or dark discoloration. This is a classic sign of pulpal necrosis following traumatic injury.
• C. INCORRECT. Tetracycline staining causes yellow, gray, or brown band-like discoloration across multiple teeth in the developing dentition. It affects all teeth developing during the period of antibiotic use, not just isolated teeth.
• D. INCORRECT. Hypocalcification produces white opaque spots or areas of reduced mineralization on enamel, not the gray/dark internal discoloration associated with pulp necrosis following trauma.