This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral Cavity, Subject name: Surgery
The most common cyst of the oral region is - 
Select and explain. 
A. Dentigerous cyst, B. Keratosis cyst, C. Dermoid cyst, D. Periapical cyst
D: Periapical cyst
Answer: D: Periapical cyst 
Explanation: Ans. (d) Periapical cystRef: Scott-Browns Otorhinolaryngology 7/e p 1924-1925Periapical Cyst (Radicular Cyst)* MC type of Jaw cyst* Inflammatory origin* Found at the apex of teeth.* Result in long standing Pulpitis.* Removal of irritant material and tooth extraction.