The edentulous area at #6 is particularly narrow (Fig.4 (coronal section)).  In contrast, the ridge at #7 is wide enough for 3 mm or smaller 1-piece implant (Fig.5).  Since the implant is palatal to the crown, an angled implant may be needed.

Narrow Ridge

Xin Wei, DDS, PhD, MS 1st edition 11/14/2015, last revision 11/14/2015