An<unk>  is a condition of teeth where<unk>  is found on locations where<unk>  is not supposed to be, such as on a root surface.  They are found usually in the area between roots, which is called a furcation, of molars.<unk> s are not common in teeth with a single root.
Enamel pearl
Keratoconus
Onychophosis
Nevus of Ota
Acrochordon
Halo nevus
Linitis plastica
Formothion