Derek, you were pretty close with your dentist reference. A medical pump would be the only safe thing to use (since the motor is isolated from the pump itself) but the cost would be most prohibitive. Unless you can find a used one somewhere, I wouldn't chance using any other electrical type vacuum.

We used to modify them to make automatic chlorinators for swimming pools and transferring hazardous chemicals from one tank to another, etc. Good luck in your search.