More unusual pigmentations of the gingiva.

Three unusual types of oral pigmentation are presented. The first is a brown orange pigmentation caused by the habit of using the bark of Juglans regia for teeth cleaning. The second is a bright yellow pigmentation associated with the habit of chewing the seeds of Cola nitida. The third is a generalized mousy brown pigmentation related to the habit of chewing the leaves of Catha edulis. The purpose of this article is to describe the nature of these pigmentations and to present their clinical and histologic features.