Abstract: An automatic fluid mixing system is disclosed which, in its preferred embodiment, discontinuously opens a disposable multi-compartmented module to permit the mixing of initially released contents before the subsequent opening of remaining compartments, flushes each compartment with base liquid, and utilizes knife-edge pairs to slit the module in a manner which permits rapid release of the contents.The preferred system additionally includes means responsive to specific gravity of the solution for controlling the amount of base liquid introduced into the solution and a level sensing mechanism including a magnetic float assembly employing magnetically responsive switches to electronically sense liquid level.

Abstract: An improved chuck wrench for contra-angle dental handpieces. The wrench includes a unitary angular C-shaped body, one of the arms of the body being provided with a socket and recess for accurately locating the wrench in position relative to the head of a handpiece when chuck adjustment (or removal) is desired. Between the paired arms is a knurled cylindrical wheel dimensioned to fit comfortably between, and be rotated by, the same fingers that receive the narrower connecting portion of the C-shaped body. A torsion spring shaft extends through the wheel and into the socket and has a non-circular end portion receivable within an opening of a handpiece chuck for locking the two parts (chuck and shaft) against independent relative rotation.