<unk>  is congenital blockage or absence of the orifice of a major<unk><unk>  duct or part of the duct itself. It is a very rare condition. The submandibular<unk><unk>  duct is usually involved, having failed to cannulate during embryological development. The condition first becomes apparent in the first few days after birth where a submandibular swelling caused by a retention cyst is noticed.
Salivary gland atresia
Salivary gland hypoplasia
Salivary gland aplasia
Persistent thyroglossal duct
Patulous Eustachian tube
Salivary duct stricture
Regional odontodysplasia
Maxillary hypoplasia