Osteotomy is initiated in the middle of the septum (Fig.4 S).  In fact, it should have been distal ~ 1 mm because of differential bone thickness.   There is bone loss buccal and lingual of the mesial socket.  A narrower implant (4.5 mm instead of 5 mm) should be placed with guide.

Osteotomy Depth Control Last Next Xin Wei, DDS, PhD, MS 1st edition 10/17/2017, last revision 04/26/2020