Solar Energy Technology, Inc.

Jay Marlin

Sheldon B Herskovitz

Martin R Stiglitz

A syringe for extruding heated thermoplastic materials through a hollow needle is disclosed. This syringe is particularly useful in obturating root canal cavities, or other dental cavities, with gutta-percha or similar materials.

Method for filling a root canal

An electrically heated endodontic syringe for injecting thermoplastic material, such as gutta percha, into a root canal cavity includes a syringe barrel for holding a supply of thermoplastic material, a heater body threadedly attached at one end to the syringe barrel and an injection needle threadedly secured to the other end of the heater body by means of a hub. A manual plunger is provided in the syringe barrel for ejecting thermoplastic material from the barrel through the heater body, hub and needle into the root canal cavity. The barrel and plunger are made of materials having a low coefficient thermal conductivity of less than about 20 Btu/(hr)(ft.sup.2) (F..degree./ft) and a thermally insulating washer is positioned between the barrel and the heater body to minimize heat transfer to the barrel. The heater body, hub and needle are made of materials having a high coefficient of thermal conductivity of at least about 200 Btu/(hr) (ft.sup.2) (.degree.F./ft) to maximize heat flow to the needle. An electric resistance heating element carried by the heater body provides sufficient heat to maintain the entire needle above 230.degree. F. at which the thermoplastic material will flow but below the temperature at which the material thermally decomposes. The needle is at least one inch long, of 18-30 gauge size, and manually malleable to enable the needle to be bent to conform to the root canal cavity.

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Leominster, MA, United States of America

Jay Marlin