The name of a place of articulation. The active articulator is the tongue tip and the passive articulator is the upper front teeth. Some writers distinguish between plain dental where the tongue tip articulates with the back of the teeth and interdental where it protrudes between the upper and lower teeth, articulating with the edges of the upper teeth. Dental sounds include θ ð. Many dental sounds are symbolised by the addition of a combining bridge diacritic (U+032A) below the symbol for an alveolar consonant, as in .