Fig.2: Prior to RCT, the outline of the septum is discernable.  Its height is ~ 10 mm.

After RCT, the outline of the septum is hard to be detected.  In fact the mesiolingual cusp fractures subgingivally (Fig.3).  This PA can be used for implant design.

Shorter Maxillary Immediate Implant

Xin Wei, DDS, PhD, MS 1st edition 07/04/2015, last revision 07/04/2015