I'm not sure if this is a "technical name", but I've heard that they are called dental dry vacuums. It's a complete system, made up of a vacuum motor and flexible hose, and once you bend it, it keeps its shape.
http://www.airtechniques.com/products/essentialUtility.aspx? SubID = 11
You need to buy a vacuum motor/jar as seen above.
http://www.ehow.com/how-does_4924492_dental-dry-vacuum-work.html
Explain quickly how they work.
