Dental impression syringe

Claim 1

A syringe for injecting a pasty material comprising: a main body formed with a longitudinal passage; and a tube removably mounted within the passage to extend through the body, a piston mounted to extend slidably through the tube, said tube formed with a longitudinal slot in a side wall thereof and provided with a handling ring at a rear part of the tube, the cross section of the passage of the main body substantially corresponding to the cross section of the tube such that the tube inserted to extend within the body establishes an injection chamber defined by an internal wall of the tube and an internal wall passage of the body extending coextensive with said slot, said slot being defined between a pair of longitudinal generally sharp edges formed in the tube side wall, each edge extending between the internal wall and an external wall of the tube to directly connect said walls together along the edge so that each edge functions as a scraping edge enabling it to move along and in contact with a surface of a mixing plate on which pasty material is disposed to enable said material to be scraped by the edge directly onto the internal wall of the tube prior to inserting the tube into the body.