Fig. 4.

Panoramic view shows the reference points and lines used for bone height and MBL measurements. A In the upper jaw, N is the lowest point of nasal floor, and A and P correspond to the lowest parts of the mesial wall and distal walls, respectively. Point I is the median point between points A and P. h is the bone height, determined by the distance between the alveolar ridge to the upper limit. B h’ is the bone height, determined by the distance between the alveolar ridge and the border of the jaw; a and b are the mesial and distal MBL, respectively, determined by the distances from the most mesial and distal points of the implant platform to the crestal bone