After extraction at #15 with 9 mm offset, a 12 mm bone trimmer is used to create a dimple in the septum. When a 4x7.3 mm drill is done according to drill sequence, initial osteotomy has no palatal wall.  A 4.5x10 mm dummy implant cannot engage for sinus lift.  DIO Sinus Approaching drill cannot enter IS green metal sleeve.  When a 4x8.5 mm drill is finished, the sinus floor is intact.  This is not the case when a 2.2x10 mm drill is used.  Water membrane lifter does not seal the osteotomy (palatal defect).  The 4.5x10 mm dummy implant is used for sinus lift, followed by 2-3 Amalgam carriers of allograft lifted with the same implant (Fig.1,2). 

Step-by-Step Last Next Xin Wei, DDS, PhD, MS 1st edition 09/03/2019, last revision 04/12/2020