A large implant (7x12 mm) placed in the middle of the socket may increase the chance to invade the root of #20 (Fig.2), as compared to that placed more distal (Fig.3).  There is possible periapical radiolucency associated with #20 (^).

Thin Septum with Deviated Roots

Xin Wei, DDS, PhD, MS 1st edition 12/04/2016, last revision 12/04/2016