Angle between Frankfort horizontal plane and occlusal plane is:

 # Angle between FH plane and Occlusal plane is:

A. 1 degree

B. 10 degrees

C. 27 degrees

D. Parallel to each other

The correct answer is B. 10 degrees.

This is from Down's analysis. The cant measures the slope of occlusal plane to the Frankfort horizontal plane. When the anterior part of plane is lower than the posterior, the angle would be positive. Large positive angles are found in Class II facial patterns. A long mandibular ramus also tends to decrease this angle. The mean value is +9.3° with a range of +1.5° to +9.3°.