Yesterday, new general dentist said i may need a sinus lift (really?) as part of an implant process. molar pulled 3 mos. earlier; no graft could hold.

Correct: If there is insufficient bone in that area, a "sinus lift" is performed to create enough height of bone to place an implant. It has become quite routine and generally not that invasive. Without enough solid bone, an implant cannot be placed.

Sinus lift: Upper molars often need sinus lifts in order to retain an implant. The roots often extend up into the sinus itself, so there seldom is enough bone to hold an implant.

Sufficient bone?: There needs to be enough quality and quantity of bone in order to support an implant in order for it to be integrated and have a good long term prognosis. Without seeing you and an x-ray of the area, we can't comment further on the need for it in your particular case. You seem to question the comment. I suggest that you consult with at least one periodontist and find a dentist whom you trust.

CBCT 3D imaging: may eliminate any questions or variables, and should be considered to achieve the highest standard of diagnosis and treatment.