Following extraction, the buccal plate (Fig.3a (coronal section): B) is not only ~ 2 mm shorter than the palatal one (P), but also thinner.  Since the bone density of the palatal plate is higher, without osteotomy an implant is less likely placed in the middle of the socket (S (Fig.1); Fig.3b) than buccal (Fig.3c).  Therefore drills are used to form osteotomy in the apical 1/3 of the palatal slope (Fig.3d (red arrow); SM: sinus membrane).  When 3.3 mm Magic Drill (MD) is in place (Fig.2), the distal surface of the sinus septum is perforated without air leakage.  Demineralized allograft (.0125-.085) is placed for sinus lift (Fi.g3e: curved blue line: sinus lift; Fig.4 *) prior to placement of 4.5x11 mm implant with ~ 30 Ncm.  The implant is slightly buccal to the ideal position indicated in Fig.3e.   Unintentional Sinus Lift Last Next Xin Wei, DDS, PhD, MS 1st edition 10/03/2016, last revision 05/19/2020