An anchoring element for use in bone has a proximal end and a distal end. The distal end may be embedded in bone with the proximal end exposed. An abutment surface is disposed toward the proximal end. The anchoring element includes four surfaces that define the distal end. A generally cylindrical first...http://www.google.es/patents/US7845945?utm_source=gb-gplus-sharePatente US7845945 - Anchoring element for use in bone
