Fig.2 (CT axial section), The tooth #14 has a large septum between 3 roots (P: palatal, MB: mesiobuccal, DB: distobuccal).  The septum can hold an implant with diameter of 5 mm.

Large Healing Abutment

Xin Wei, DDS, PhD, MS 1st edition 12/10/2013, last revision 12/24/2013