Fig.2a is a cross section of a normal upper incisor socket with thin buccal plate (B) and thick palatal one (P).  It is difficult to initiate osteotomy in the oblique palatal wall when the buccal plate is resorbed (Fig.2b).  In this case with horizontal buccal and palatal plate bone loss, the socket bottom is flat (Fig.2c red), easy for osteotomy (Fig.2d green arrow, Fig.3).

Incisive Canal Last Next Xin Wei, DDS, PhD, MS 1st edition 12/04/2017, last revision 08/13/2018