An adapter for coupling a compule with a dental handpiece including a piston. The compule contains a dental material. The adapter includes a coupling portion that defines openings for attaching the adapter to the compule and for attaching the adapter to the dental handpiece. A plunger portion extends through one opening and engages the piston. A breakable tab connects the coupling portion and the plunger portion and breaks during dispensing of the material. The plunger portion is then movable relative to the coupling portion. A tip for use with the dental handpiece includes a housing that defines a chamber. A needle extends from the housing and defines a lumen having an opening from which the dental material is dispensed. A plunger slides within the chamber to push the dental material through the lumen and includes a rib that seals the plunger against the chamber during sliding movement of the plunger.