A core for obturating a root canal includes a body that has a pre-formed contour that closely matches a contour of the root canal. When the core is inserted in the root canal with or without sealer, there are essentially no voids in the root canal. A method of making a customized root canal obturation core includes generating a three-dimensional image of a root canal. The method also includes manufacturing the customized root canal obturation core based on the three-dimensional image of the root canal. The customized root canal obturation core has a preformed contour that closely matches a contour of the root canal such that when the core is inserted in the root canal with or without sealer there are essentially no voids in the root canal.