When the affected tooth is extracted, the buccal plate is lost (Fig.1A (coronal section): B).  The septum is low (S), while the buccal slope of the septum is perforated (red dashed line).  Therefore the palatal (P) socket is the only suitable site for implant.  Osteotomes (Fig.1C: green) are used to create osteotomy and sinus lift, followed by taps.  Effort to direct the coronal end of the osteotomes and taps (Fig.2 T) in the middle of the socket fails.  Fig.1B is the occlusal view of the palatal socket (2 circles) with the septum (S).  To facilitate change in trajectory, Lindamann bur is used to make slot the buccal wall of the palatal socket and the septum (Fig.1C,D red lines). 

Change in Trajectory Next Xin Wei, DDS, PhD, MS 1st edition 10/29/2015, last revision 12/25/2018