Fig. 2

Schematic diagram of radiographic measurements. (0- the root apex; 1- the intersection of the labial-lingual CEJ line and the long axis; 2- the intersection of the labial alveolar bone surface and the line perpendicular to the long axis through dot 0; 3- the mid-root point of the labial root surface; 4- the intersection of the labial alveolar bone surface and the line perpendicular to the long axis through dot 3; 5- the point 2 mm below the labial CEJ; 6- the intersection of the labial alveolar bone surface and the line perpendicular to the long axis through dot 5; 7- the labial CEJ; 8-the alveolar crest.)