An elongate cylindrical body member is adapted for permanent anchoring of its lower end into bone tissue and constructed to support an attached device such as a tooth at its upper end. The body member has an external screw thread formed in its outer surface, and at least one cavity defined therein adjacent its bottom end. Each cavity forms at its intersection with the screw thread at least one cutting edge for self-tapping as the body member is screwed into the bone tissue. Such cavity defines a total volume within the outer surface of said body member sufficient to retain all the bone tissue material which is removed as a result of the self-tapping operation. The cavity stops short of the lowermost end of the body member so as to maintain the bottom end of the body member imperforate, whereby the screwing of the body member into a pre-formed receiving aperture formed in the bone tissue causes the resulting particles of bone tissue to collect in the cavity, thereby promoting the securing of the body member into the aperture, while the bottom of the receiving aperture remains free of the bone particles because of its imperforate bottom lower end member.