A traditional lateral approach to the sinus involves either very careful drilling with large diamonds, or a piezo unit. Having read some very positive reviews, I used the DASK drill set for an external sinus lift. This has an internal irrigation system, that delivers water from the drill tip. Thus as the buccal bone is removed, and you get to the sinus membrane, hydrostatic pressure pushes the membrane out of the way, significantly reducing the risk of tearing the membrane. Not only is risk of membrane tears reduced, but so was surgical time. Contact me if you wish further information, but have been impressed with this system.