Patent ID: 8821161

Claim:
A prophy angle comprising a housing, wherein the housing includes a paste chamber, a drive mechanism and paste dispensing assembly within the housing; wherein the prophy angle drive mechanism includes a drive shaft configured for delivering mechanical energy to a rotatable head assembly provided at a distal end of the prophy angle housing; wherein the prophy angle also includes a housing tube configured to fit about at least a portion of the drive shaft of the drive mechanism; the paste dispensing assembly further comprising a pushrod arranged on at least a portion of the drive shaft of the drive mechanism and said housing tube, wherein when the housing tube and pushrod are joined together in mechanical engagement, contact between the drive shaft and paste that may be stored within the chamber of the prophy angle housing is precluded in order to maintain effective functioning of the drive mechanism in the presence of paste; said pushrod further comprising a distal tip at least partially overlapping a proximal end of the housing tube; a spring arranged within the distal tip of the pushrod and abutting the proximal end of the housing tube, the spring configured to permit reciprocal movement of the pushrod linearly relative to the housing tube, wherein reciprocal movement of the pushrod is caused by a user controlled actuator positioned at a proximal end of the pushrod such that distal movement of the actuator causes distal movement of the pushrod and whereupon release of the actuator, the spring causes proximal movement of the pushrod; and a generally cylindrical plunger positioned on at least a portion of the pushrod between the actuator and the spring, the plunger comprising an opening therein to permit passage of the pushrod there through when in use, the plunger comprising a generally cylindrical seal comprising resilient but sturdy material to pressurize and push the paste contents within the chamber in a distal direction while resisting the passage of pressurized paste between the seal and an interior wall of the prophy angle housing and between the seal and the pushrod when the paste dispensing assembly is in use in the prophy angle, the plunger further comprising a generally cylindrical retainer clip secured to the generally cylindrical seal to preclude proximal movement of the plunger when the actuator is released by the user during use; whereby distal movement of the actuator causes distal movement of the pushrod and the generally cylindrical plunger to direct paste in a distal direction when in use in the prophy angle, and whereby release of the actuator causes proximal movement of the pushrod by the spring, but not the generally cylindrical plunger such that continued actuation of the actuator caused controlled quantities of paste to be delivered out of the prophy angle.