These units have many uses including roughening porcelain or composite prior to making intraoral repairs, roughening any indirect bonded restoration (resin, ceramic, or metal) prior to cementation with a resin cement, and roughening the internal surfaces of conventional crowns, inlays, etc. to increase the bond strength to traditional cements.
What is the correct air pressure to operate these devices? Originally, the recommended operating pressure was 60-100psi. Now, with handpiece airline adapters available as an alternative to the quick disconnects, sandblasting can be performed at pressures as low as 30psi. Even though there is preliminary evidence that a specific air pressure may not be critical for optimal bond strengths, the data is too limited to make a definitive determination at this time.
Indeed, we may find that different materials require different pressures. For example, composite, due to its relative softness, may achieve its highest bond strengths after being sandblasted at 30psi, while porcelain may require 60psi.
However, higher air pressures (60-00psi) will complete a task more quickly. To get 60-100psi air pressure, the connection to your air supply should be made prior to the pressure reducer in a typical dental unit.
The ability to connect a sandblaster to a handpiece airline allows maximum portability without any installation whatsoever. But you must remove a handpiece to accommodate its connection, unless you have an unused airline in your dental unit. Therefore, the aforementioned quick disconnect, installed into your dental unit, is probably the best solution for portability and convenience.