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: Periapical Cyst (Radiocular Cyst) MC type of jaw cystQ Inflammatory in origin. Extremely common lesions found at the apex of teethQ. Develop as a result of long-standing pulpitis, caused by advanced carious lesions or by trauma to the tooth. Periapical inflammatory lesions persist as a result of the continued presence of bacteria or other offensive agents in the area. Treatment: Complete removal of offending material and appropriate restoration of the tooth or extraction.