One method to control osteotomy depth for immediate implant is to use the gingival margin.  As Fig.1 indicates, the gingival margin is uneven at the site of #18.  Since the osteotomy in this case is established mesially, large drills and implants may distort the gingiva so that the gingival margin is an unreliable landmark.

Secure Landmark for Osteotomy   Next  Xin Wei, DDS, PhD, MS 1st edition 03/20/2017, last revision 12/28/2019