A 15-year-old White female patient sought treatment from her general dentist, reporting a 2-month history of asymptomatic dark spots on her mandibular left gingiva. Her general dentist referred her to a periodontist for evaluation. The patient was a never-smoker with an unremarkable medical history and no known allergies. She did not take any medications. Before onset, the patient had been using an activated-charcoal whitening dentifrice for approximately 2 years. Examination revealed several poorly demarcated slate-gray macules of the maxillary facial marginal gingiva of teeth nos.