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An endodontic instrument extractor tool is configured for removing a fragment of a broken endodontic instrument that has become lodged within a root canal of a tooth. The extractor tool comprises an elongate shaft, including a hollow gripping body at a distal end, and a proximal handle portion. The

An endodontic instrument extractor tool is configured for removing a fragment of a broken endodontic instrument that has become lodged within a root canal of a tooth. The extractor tool comprises an elongate shaft, including a hollow gripping body at a distal end, and a proximal handle portion. The hollow gripping body includes an inside diameter that is initially greater than a cross-sectional dimension of a fragment of a broken endodontic instrument to be removed from a root canal of a tooth. The inside diameter of the hollow gripping body defines a hollow interior cavity portion into which at least a portion of the fragment is receivable. At least the hollow gripping body of the body is formed of a shape memory alloy (e.g., nickel-titanium) or polymer in an expanded configuration so that upon heating, the shape memory alloy or polymer returns to its unexpanded configuration, tightly gripping around a proximal end of the fragment.

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What is claimed is: 1. An endodontic instrument extractor tool for removing a broken endodontic instrument that has become lodged within a root canal of a tooth, comprising: an elongate shaft having a proximal end and a distal end, at least the distal end of the elongate shaft being insertable into

What is claimed is: 1. An endodontic instrument extractor tool for removing a broken endodontic instrument that has become lodged within a root canal of a tooth, comprising: an elongate shaft having a proximal end and a distal end, at least the distal end of the elongate shaft being insertable into root canal of a tooth, the elongate shaft having a length so that the proximal end extends outside the tooth when the distal end is positioned within a root canal of a tooth; and gripping means formed of a shape memory material, disposed at the distal end of the elongate shaft, for gripping a portion of a broken endodontic instrument that has become lodged within a root canal of a tooth by causing the gripping means to shrink around at least a portion of the broken endodontic instrument in response to application of heat energy to the gripping means. 2. An endodontic instrument extractor tool as recited in claim 1, wherein the gripping means comprises a hollow body having an outer wall defining a hollow interior portion and. 3. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall is flared. 4. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall of the hollow body is substantially cylindrical. 5. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall of the hollow body has a substantially smooth interior surface for contacting the broken endodontic file. 6. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall of the hollow body has a roughened interior surface for contacting the broken endodontic file. 7. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall of the hollow body has a diameter that exceeds the diameter of the distal end of the elongate shaft. 8. An endodontic instrument extractor tool as recited in claim 2, wherein the inside diameter of the hollow interior portion of the hollow body is initially between about 0.03 mm and about 1.75 mm. 9. An endodontic instrument extractor tool as recited in claim 2, wherein the outer wall of the hollow body comprises a nickel-titanium alloy having shape memory. 10. An endodontic instrument extractor tool as recited in claim 9, wherein the nickel-titanium alloy comprises at least about 40% titanium. 11. An endodontic instrument extractor tool as recited in claim 10, wherein the balance of the nickel-titanium alloy consists essentially of nickel. 12. An endodontic instrument extractor tool as recited in claim 10, wherein the balance of the nickel-titanium alloy further comprises nickel and at least one of copper and/or niobium. 13. An endodontic instrument extractor tool as recited in claim 9, wherein the nickel-titanium alloy comprises at least about 50% titanium. 14. An endodontic instrument extractor tool as recited in claim 1, further comprising an enlarged gripping handle at the proximal end of the elongate shaft. 15. An endodontic instrument extractor tool for removing a broken endodontic instrument that has become lodged within a root canal of a tooth, comprising: an elongate shaft having a proximal end and a distal end, at least the distal end of the elongate shaft being insertable into root canal of a tooth, the elongate shaft having a length so that the proximal end extends outside the tooth when the distal end is positioned within a root canal of a tooth; and a hollow gripping body disposed at a distal end of the elongate shaft having an outer wall defining a hollow interior portion having an initial diameter that is greater than an outer cross-sectional dimension of a broken endodontic instrument to be extracted, the hollow body comprising a material having shape memory such that, upon heating to above a minimum threshold temperature, the hollow body shrinks in size in order for the hollow interior portion to have reduced diameter so as to thereby grip the broken endodontic instrument within the hollow interior portion. 16. An endodontic instrument extractor tool as recited in claim 15, wherein the outer wall of the hollow body comprises a nickel-titanium alloy having shape memory. 17. An endodontic instrument extractor tool as recited in claim 1, wherein the endodontic instrument extractor tool is included as part of a kit that also includes an endodontic coring tool comprising a hollow tube and a cutting surface at a distal end of the hollow tube for coring around a fragment of a broken endodontic instrument. 18. A kit as recited in claim 17, further comprising a plurality of endodontic instrument extractor tools and endodontic coring tools of different sizes in order to facilitate extraction of differently-sized broken endodontic instruments that may individually become lodged in a root canal of a tool. 19. A method of removing a fragment of a broken endodontic instrument that has become lodged within a root canal of a tooth during an endodontic procedure, comprising: selecting an endodontic instrument extractor tool as defined in claim 1; inserting the gripping means and distal end of the elongate shaft of the endodontic instrument extractor tool into a root canal of a tooth in order for the gripping means to engage an end of a broken endodontic instrument lodged in the root canal; heating the gripping means in order to cause the gripping means to securely grip the end of a broken endodontic instrument; and removing the broken endodontic instrument from the root canal. 20. A method as recited in claim 19, further comprising coring around an end of the broken endodontic instrument prior to inserting the endodontic instrument extractor tool into the root canal. 21. A method as recited in claim 19, wherein heating the gripping means is accomplished by electrical resistance heating. 22. A method as recited in claim 19, wherein heating the gripping means is accomplished by exposure to body heat. 23. A method as recited in claim 19, wherein the gripping means is heated to a temperature between about 110�� F. and about 200�� F. 24. A method as recited in claim 19, wherein the gripping means is heated to a temperature between about 130�� F. and about 180�� F. 25. A method as recited in claim 19, wherein the gripping means is heated to a temperature between about 135�� F. and about 160�� F.