Seibert Classification
Question: Class I
Answer: Buccolingual loss of tissue contour with a normal apicocoronal height
Question: Class II
Answer: Apicocoronal loss of tissue with normal buccolingual contour
Question: Class III
Answer: A combination of buccolingual and apicocoronal loss
Question: Ridge described according to the depth of loss: Mild
Answer: Less than 3 mm
Question: Ridge described according to the depth of loss: Moderate
Answer: 3-6 mm