Abstract: A selectively operable removable purge unit is provided for flushing and disinfecting a primary line through which water is directed in normal operation of a dental unit to various devices in the unit, the purge unit including a solution reservoir, a double inlet single outlet router valve, an inlet air line removably connectable between a pressurized air source and either the reservoir or the router valve, and lines between the reservoir solution and the router valve and the router valve and the primary water line.

Abstract: In a method of making repositionable pressure sensitive adhesive of tacky elastomeric microspheres wherein the microspheres are polymerized and formed in an aqueous suspension which includes a surfactant, a certain amount of the surfactant is removed from the aqueous suspension after completion of polymerization of the microspheres so that a predetermined reduced amount of surfactant remains, with the result that migration of the surfactant from the adhesive is at least substantially reduced.

Abstract: In a chime tube suupported by a coaxial hanger cord, a resilient clip element connecting the cord and the interior of the chime tube having two or more legs which have a straight line length longer than the inside radius of the chime tube before insertion and which bend to grip the inside of the chime tube upon insertion and hold the clip element at the desired position.