Although the 5 mm tap and 8 mm implant (Fig.5  I) appear to protrude into the sinus cavity, there is no air leakage.  The implant appears to be supported by the native bone in the sinus (*). 

Fig.6: 1 month 20 days postop.

8 mm Implant

Xin Wei, DDS, PhD, MS 1st edition 09/21/2015, last revision 11/17/2015