Sub-Crestal Placement

Incision reveals that the ridge is moderately atrophic.  As planned, the initial osteotomy depth is 10 mm (Fig.1).  It is still safe when a 5x12 mm drill with stopper is in place (Fig.2).  The osteotomy is deepened by 2 mm with 4.5 mm drill before placement of a 5x12 mm implant with ~ 1 mm implant thread exposure buccally (Fig.3 ^).  After placement of a 6.8x4(2) mm abutment (Fig.4), there is no occlusal clearance, while there is space between the implant and the superior border of the Inferior Alveolar Canal (red dashed line).  With removal of the abutment, the implant is placed deeper (~ 1 mm) until the buccal thread is buried subcrestally. 

There is crestal bone loss 3 months postop, especially distally (Fig.5 *).  There appears to be bone graft mesially.

Return to Lower Molar Immediate Implant Limited Ortho

Xin Wei, DDS, PhD, MS 1st edition 12/24/2015, last revision 07/28/2019