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
Main drawback of calcium hydroxide apexification compared with MTA: 
Select and explain. 
A. More treatment time, B. Incomplete apical barrier, C. Incomplete coronal barrier, D. Reduced physical strength of dentin
D: Reduced physical strength of dentin
Answer: D: Reduced physical strength of dentin 
Explanation: Apexification with calcium hydroxide is almost similar when compared with MTA about given options, except achieved physical strength of dentin, which is comparatively less in Ca(OH)2.