Question

What is the most common cause of oroantral fistula?

• A. Tuberculosis
• B. Penetrating injury
• C. Tooth extraction
• D. Iatrogenic

Hint:

Upper molar roots lie near the antral floor; extraction is the commonest cause.

Answer 1

The Correct Option is C

Step 1: An oroantral fistula is an abnormal communication between the maxillary antrum (sinus) and the oral cavity. Identifying the most common cause requires knowing the close anatomical relationship of the upper molar roots to the floor of the maxillary sinus.

Step 2: Dental extraction is the most important and most common cause. The maxillary first molar alone accounts for about 50% of extraction-related oroantral fistulas, with the second and third molars accounting for the rest. This makes option (c) correct.

Step 3: Infections such as tuberculosis, syphilis and leprosy of the maxillary bone can cause a fistula but are far less common, so option (a) is wrong. Penetrating injuries or fractures of the maxilla and iatrogenic causes (for example failure of healing after Caldwell-Luc surgery) are also recognised but uncommon causes, so options (b) and (d) are not the most common.

Step 4: Clinically the patient has regurgitation of food into the nose, foul-smelling discharge and inability to build positive or negative pressure in the mouth. The leading cause remains tooth extraction.