A carpule for a dental syringe provides an internal piston disposed between a front septum and a rear plunger. The internal piston is hollow and includes a thin membrane front. The internal piston is designed to offer minimum resistance to movement in the carpule body to allow for aspiration and for easy dispensing. The internal piston divides the carpule into two anesthetic chambers, allowing an anesthetic without a vasoconstrictor and an anesthetic with a vasoconstrictor to be dispensed sequentially in a single injection and without causing undue trauma to the patient.
