An immediate implant will be placed at #17 after bridge removal (Fig.3 blue).   It appears that a 5x13 mm implant is safe for the site with enough clearance for 5.5x4(2) abutment (pink).

Once the implant osteointegrates, it will be used an anchorage (direct (instead of indirect), most efficient) to upright the tooth #18 (change the longitudinal axis from red line to purple one (Fig.4); white circle: center of resistance (rotation)).  Then an implant will be placed at #19 (white rectangle).

Implant As Upright Anchorage

Xin Wei, DDS, PhD, MS 1st edition 11/16/2016, last revision 11/16/2016