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.