A plunger for advancing a substance in a syringe toward a dispensing nozzle. The plunger has a plunger rod and a seal and being formed of a plastic composition. The plastic composition includes a polymer and a filler which is non-uniformly distributed within the polymer to provide the plunger rod and the seal with different mechanical properties depending on the filler content in the portions of the plastic composition plunger forming the rod and the seal. The invention preferably provides a dental syringe which can be conveniently used, and further helps minimizing costs in the manufacturing of the dental syringe.