In fact there is no bone apically, although the sinus membrane is intact.  After try in of various taps (tapered and cylindrical, bone- and tissue-level), a 8x14 mm dummy implant is placed (Fig.2), followed by Osteogen plug and the same sized definitive implant, which has to be placed deeper to obtain ~ 45 Ncm (Fig.3).  There is minimal thread engagement.  If the implant fails, place 2 layers of PRF membrane apically, bone graft and 1 layer of PRF coronally for ridge preservation.  When the implant heals, take Orthogonal panoramic X-ray (left) to determine exactly how many threads are involved in bone contact.

Rescue Screw Implant Last Next Xin Wei, DDS, PhD, MS 1st edition 04/30/2018, last revision 09/20/2018