This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Dentin island are frequently found in the root canals of which of the following permanent teeth 
Select and explain. 
A. Upper 2nd Molar, B. Upper 2nd Premolar, C. Lower 2nd Molar, D. Lower 2nd Premolar
B: Upper 2nd Premolar
Answer: B: Upper 2nd Premolar 
Explanation: None