Dental OSCE (Objective Structured Clinical Examination) Practice Exam

The condition known as black hairy tongue is primarily caused by the elongation and accumulation of filiform papillae on the dorsum of the tongue. These papillae, which are normally small and slender, become elongated and can trap food particles, bacteria, and dead cells, leading to a dark coloration. The presence of chromogenic bacteria, which can produce pigments, may contribute to the characteristic black appearance.

In contrast, the other options involve different types of papillae or conditions that do not directly relate to the features of black hairy tongue. For instance, elongation of fungiform papillae and inflamed circumvallate papillae do not result in the same accumulation or pigmentation effects as seen with the filiform papillae. Atrophic papillae, on the other hand, are usually reduced in size and may lead to a smooth tongue, which does not present the hairy appearance characteristic of this condition. Therefore, the correct cause of black hairy tongue is linked specifically to the elongation of the filiform papillae.