In addition, the distal defect may be not even buccolingually, as indicated by white and red arrowheads in Fig.4.  The lingual wall of the socket may be lower than the buccal one, or vice versa.  The distance between the apex of the tooth and the upper border of the Inferior Alveolar Canal is 5 mm.  After tooth extraction, measure the depth of the socket against a reliable reference point (gingival margin or better the crest).  It should be safe if the depth of the osteotomy is 3 mm.

Complex Distal Defect

Xin Wei, DDS, PhD, MS 1st edition 04/12/2015, last revision 04/12/2015