RCT was retreated in 2013 (Fig.2).  The mesial  periodontal ligament space increases in 2015 (Fig.3 *).  Yellow dashed line: the apex of the tooth #20; red dashed line; Mental Loop.

Implant Within Apex

Xin Wei, DDS, PhD, MS 1st edition 06/29/2017, last revision 06/29/2017