Endosseous dental implants and abutments for deterring tissue loss, such as loss of buccal bone, at the site of the implant/abutment. An exemplary implant may include longitudinally extending externally threaded and unthreaded regions each extending over only a circumferential portion of the external circumference of the implant. The implant may include an internal passage extending along the shaft having a frusto-conical region extending over only a circumferential portion of the internal passage. An exemplary abutment may include a distal connection end comprising a frusto-conical region thereat extending over only a circumferential portion of the external circumference of the connection end to provide a frusto-conical connection region and non-frusto-conical connection region.
