Most common cause of oroantral fistula
A most impoant cause of oroantral fistula is dental extraction. It is a communication between the antrum and the oral cavity. Roots of the second premolar and upper molars are closely related to the antral cavity and their extraction may lead to fistula formation. It presents with regurgitation of food foul smelling discharge filling nose and inability to build positive or negative pressure in the mouth. Ref: Textbook of diseases of ENT; PL Dhingra; 7th edition, pg 208
TB
Penetrating injury
Tooth extraction
Iatrogenic
Nose and paranasal sinuses