CT reveals possible 3 palatal threads exposed (Fig.4,5 arrowheads), which is associated with change in trajectory due to the palatal shift of the apex of the implant (arrow), as compared to the design of the bone-level implant (Fig.6).  When there is a slope in the ridge and/or sinus floor, do not shift implants and use the guide for implant placement.  If switching is necessary, use a final drill without underprep (Fig.7 red) through the sinus floor after sinus lift to avoid apical implant deviation.

Sloped Sinus Floor Last Next Xin Wei, DDS, PhD, MS 1st edition 08/30/2019, last revision 01/23/2020