Abstract: A crossover prevention valve for use in a multi-component fluid mixing and dispensing system includes a valve body defining at least two fluid passageways having respective one-way check valves at their outlet ends. A forward end of the valve body cooperates with an interior surface of a dispensing nozzle to define a mixing chamber for chemically reactive fluids prior to discharging the mixed fluids out of the dispensing nozzle. The crossover prevention valve does not permit reverse flow, thereby preventing clogs due to undesired intrusion of one reactant into the flow path of another reactant. Solidified reactants left in the mixing chamber are easily removed from the valve body, permitting the valve body to be reused even after sitting for extended periods.

Abstract: A crossover prevention valve for use in a multi-component fluid mixing and dispensing system includes a valve body defining at least two fluid passageways having respective one-way check valves at their outlet ends. A forward end of the valve body cooperates with an interior surface of a dispensing nozzle to define a mixing chamber for chemically reactive fluids prior to discharging the mixed fluids out of the dispensing nozzle. The crossover prevention valve does not permit reverse flow, thereby preventing clogs due to undesired intrusion of one reactant into the flow path of another reactant. Solidified reactants left in the mixing chamber are easily removed from the valve body, permitting the valve body to be reused even after sitting for extended periods.

Abstract: Providing a finger ring retainer for a container of prophylaxis dental paste from elongated formable material segments, each segment having two end portions and a central portion, the two end portions having arcuate configurations greater than 180.degree. in extent so that one end portion can be fitted onto a human finger and the second end portion can be fitted onto a container of dental paste, the central portion being bent at an approximately 45.degree. apex angle sufficient to create a pair of doubled over layers of said central portion extending generally normal to each other in substantially parallel planes.

Abstract: An integral recyclable dental floss package/container/dispenser, and a blank therefor, having an integral structure of one-piece, biodegradable material, preferably paperboard, there being a hang tab integral with extending upwardly from, and separable from, the back panel. The top closure has an inner panel extending rearwardly from the fornt panel, having a floss dispensing orifice and cutter, and an outer top cover panel extending forwardly from the rear wall.