The socket shield at #11 is apparently incomplete, since the apical gutta percha (Fig.2 <) and the apex of the root (Fig.2,3 R) are not removed.  The bone is hard when a 1.6 mm drill is being used (Fig.2) as the apical native bone is almost exclusively composed of the cortices.  Two of the apical threads of 3.5x13 mm implant are bent (Fig.3).  Failure of socket shield is related to retention of the apex (Fig.6 < Lingual view).

Shield Removal Last Next Xin Wei, DDS, PhD, MS 1st edition 12/16/2018, last revision 12/16/2019