Patent ID: 7776010

Claim:
A syringe-in-syringe mixing system for use in mixing a two-part dental composition comprising: a first component contained in an inner hollow plunger with a first plunger slidable within the inner hollow plunger; a second component contained in a syringe barrel, the inner hollow plunger being disposed within the syringe barrel so that after the first plunger slides into and is locked within the inner hollow plunger, the inner hollow plunger and first plunger may together be used to function as a second plunger for the syringe barrel; the inner hollow plunger including an integrally formed sealing plug and rupturable membrane disposed over a dispensing end of the inner hollow plunger; the integrally formed sealing plug and rupturable membrane including a sealing plug portion laterally disposed around said dispensing end of the inner hollow plunger so as to terminate at an opening of the dispensing end and so as to sealingly engage against the interior of the syringe barrel; and the integrally formed sealing plug and rupturable membrane comprising a rupturable membrane portion that extends over the dispensing end of the inner hollow plunger at the point where the sealing plug portion terminates at said opening of the dispensing end, forming an uninterrupted surface across the entirety of the sealing plug portion and the membrane portion at which the sealing plug and membrane portions both terminate, and wherein by sliding the first plunger into the inner hollow plunger when expelling the first component, pressure against the membrane portion causes rupture of the membrane portion, introducing the first component into the syringe barrel so that the first component contacts the second component.