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
The zero degree anatomic teeth is used in: 
Select and explain. 
A. Sharp ridge, B. Flat ridge, C. Ridge with undercut, D. Well contoured ridge
B: Flat ridge
Answer: B: Flat ridge 
Explanation: Monoplane Occlusion

Cuspless teeth (0o) on a flat plane with 1.5-2.0 mm overjet.
No cusp to fossa relationship
No anterior contacts in centric position
Poor residual ridges
Poor neuromuscular control (Bruxers, CP, etc.,)
Previously successful with monoplane dentures or severely worn occlusion on the previous denture
Arch discrepancies
	- Class II or III or Cross-bite
Immediate Dentures
	- Except when opposing natural dentition
Potential poor follow-up.