Fig. 2
From: Alveolar bone remodeling during maxillary incisor intrusion and retraction
Reference lines used to determine the extent of intrusion and retraction of the incisor. Difference in the distance from incisor tip to Frankfort plane at pre-treatment and post-treatment (V0–V1) represents the amount of intrusion of incisor. Difference in the distance from incisor tip to N-perpendicular line at pretreatment and posttreatment (H0–H1) represents the amount of retraction of incisor