The present article is a case report on the cusp expression of protostylid in the deciduous inferior molars and in the first permanent inferior molar, in which the correspondence and bilateral symmetry of the mentioned expression can be evidenced, as well as the their relation with the foramen cecum of the mesiobuccal furrows of the deciduous and of the permanent inferior molars.
Keywords: Deciduous and permanent mandibular molars; dental anthropology; dental morphology; nonmetric dental traits; protostylid.