Patent ID: 8641416

Claim:
A syringe ( 1 ) for dosed dispensing of free-flowing and/or pasty dental materials, said syringe comprising: a. a sleeve ( 10 ) for accommodating material and b. a piston ( 15 ) which can be inserted into the sleeve ( 10 ), comprising: i. a piston member ( 15 ′) having an axial face and a radial face with an annular recess, ii. a frictional engagement element ( 25 ) having a first surface which frictionally abuts an inner wall ( 35 ) of the sleeve ( 10 ) and a second surface is received in said annular recess, and iii. an elastic element ( 30 ) extending between said first surface and second surface and coupling the frictional engagement element ( 25 ) and the piston member ( 15 ′), wherein the sleeve ( 10 ) and the piston ( 15 ) inserted into the sleeve ( 10 ) define an inner sleeve chamber ( 70 ) for accommodating the material, wherein the elastic element ( 30 ) can be tensioned by relative lag of the first surface of the frictional engagement element ( 25 ) in relation to the piston member ( 15 ′) when the piston ( 15 ) and/or the piston member ( 15 ′) is inserted into the sleeve ( 10 ), said frictional engagement element and an inner surface of said sleeve being arranged to provide a frictional force therebetween to cause the relative lag of the first surface of the frictional engagement element and the tensioning of the elastic element, wherein by relaxing the elastic element ( 30 ) it is possible for the piston member ( 15 ′) to be expelled at least partially from the sleeve ( 10 ) while the frictional engagement element ( 25 ) remains motionless, in order to increase the volume of the inner sleeve chamber ( 70 ).