A dental implant system comprising: a lower implant body configured to be implanted in bone and defining a centerline; an upper implant body configured to be coupled to the lower implant body, thereby forming a cavity between the upper and lower implant bodies, the upper implant body comprising an opening to the cavity; and a rotatable, swivelable anchor comprising: a base disposed at least partially within the cavity, the base comprising a substantially spherical surface; and a shaft coupled to the base and extending through the opening, wherein the upper implant body further comprises an internal surface comprising a substantially spherical surface, configured such that the substantially spherical surface of the base is at least partially in contact with the internal surface when the upper and lower implant bodies are coupled together with the base of the anchor disposed within the cavity, wherein the opening passes through the substantially spherical surface of the internal surface, wherein the lower implant body comprises an anti-rotation post configured to project into the cavity when the upper and lower implant bodies are coupled together; and the base further comprises an anti-rotation cavity configured to engage the anti-rotation post when the base of the anchor is disposed within the cavity; and the anti-rotation post and anti-rotation cavity are configured to resist rotation of the anchor about the centerline of the lower implant body while allowing rotation of the anchor about axes perpendicular to the centerline. a lower implant body configured to be implanted in bone and defining a centerline; an upper implant body configured to be coupled to the lower implant body, thereby forming a cavity between the upper and lower implant bodies, the upper implant body comprising an opening to the cavity; and a rotatable, swivelable anchor comprising: a base disposed at least partially within the cavity, the base comprising a substantially spherical surface; and a shaft coupled to the base and extending through the opening, wherein the upper implant body further comprises an internal surface comprising a substantially spherical surface, configured such that the substantially spherical surface of the base is at least partially in contact with the internal surface when the upper and lower implant bodies are coupled together with the base of the anchor disposed within the cavity, wherein the opening passes through the substantially spherical surface of the internal surface, wherein the lower implant body comprises an anti-rotation post configured to project into the cavity when the upper and lower implant bodies are coupled together; and the base further comprises an anti-rotation cavity configured to engage the anti-rotation post when the base of the anchor is disposed within the cavity; and the anti-rotation post and anti-rotation cavity are configured to resist rotation of the anchor about the centerline of the lower implant body while allowing rotation of the anchor about axes perpendicular to the centerline. a base disposed at least partially within the cavity, the base comprising a substantially spherical surface; and a shaft coupled to the base and extending through the opening, wherein the upper implant body further comprises an internal surface comprising a substantially spherical surface, configured such that the substantially spherical surface of the base is at least partially in contact with the internal surface when the upper and lower implant bodies are coupled together with the base of the anchor disposed within the cavity, wherein the opening passes through the substantially spherical surface of the internal surface, wherein the lower implant body comprises an anti-rotation post configured to project into the cavity when the upper and lower implant bodies are coupled together; and the base further comprises an anti-rotation cavity configured to engage the anti-rotation post when the base of the anchor is disposed within the cavity; and the anti-rotation post and anti-rotation cavity are configured to resist rotation of the anchor about the centerline of the lower implant body while allowing rotation of the anchor about axes perpendicular to the centerline.