An implant for insertion into a patient includes a superior surface disposed at a first end of the implant and an inferior surface disposed at a second, opposite end of the implant. The superior and inferior surfaces of the implant are constructed with curvatures that approximately match the morphology of vertebral endplates. The inferior surface and superior surface may include the same or different radii of curvature within the coronal and sagittal planes. The inferior surface and superior surface may be defined by spherical radii. The radius of the superior surface may be about 60 percent to 74 percent of the radius of the inferior surface.