National Board Dental Hygiene Examination (NBDHE) Dental Hygienist Practice Test

The condition characterized by the abnormal accumulation of keratin on the filiform papillae of the tongue, leading to a dark, hair-like appearance is known as black hairy tongue. This occurs when there is a disruption in the natural exfoliation process of the epithelial cells on the tongue's surface. Normally, the epithelial cells should shed regularly, allowing for the renewal of the tongue's surface. However, in black hairy tongue, factors such as poor oral hygiene, smoking, certain medications, and dry mouth can hinder this normal shedding process, causing the keratinized cells to accumulate and form a discolored, elongated appearance resembling hair.

This condition is not directly related to geographic tongue, which is characterized by patches of smooth, red areas appearing on the tongue's surface due to the loss of papillae without the hairy appearance. Halitosis, or bad breath, is a separate issue typically stemming from bacteria or food particles rather than an epithelial shedding disorder. Melanin pigmentation refers to darker pigmentation of the mucosal surfaces and is not related to the exfoliation of epithelial cells, but rather to a pigmentation process. Thus, black hairy tongue is specifically linked to the failure of normal epithelial cell turnover on the tongue.