Since there is a lot of scattering from nearby crowns, the implant at #20 will be placed free hand.  To overcome the thick dense lingual plate (Fig.8 L), osteotomy is initiated (Fig.9 red line) in the middle of the lingual wall of the extraction socket (black area) on the top of the socket shield (S). 

Sticky Bone Last Next Xin Wei, DDS, PhD, MS 1st edition 12/21/2019, last revision 12/21/2019