182 Theories and techniques of oral implantology

Trying to take some of the occlusal weight off the crest of the jawbone, various operators fashioned more complicated mesh-like flanks. One such at-tempt is that of Hans Nordgren of Sweden (Fig. 5-90) . Here only thin bars connect the flanks, and a very narrow abutment post protrudes from the connecting bar.

Recognizing the value of their predecessor's work in eliminating the amount of metal on bone, the Americans Art Jermyn (Fig. 5-91) , Norman

Fig. 5-91. Mandibular subperiosteal implant of Jermyn. A, Some resorption is seen around the screw, probably because the screw may not have been placed through the center of the hole in the implant, causing a torque on the screw. B, A large area of resorption is now seen around the screw. C, The screw and part of the screw recess have been removed, and the bone has healed. (Courtesy A. Jermyn.)

Cranin, Mentag, and Linkow continued designing full restorations for the mandible. These were basic-ally variations of the later implants of Gershkoff and Goldberg and Lew.

Salagaray and Sol from Madrid, Spain, also fashioned subperiosteal implants. They designed a very simple implant, whose buccal and lingual parts were single metal bars. Spanning the bars were four cross-struts that bore the abutment posts. They grooved the bone so that the implant framework would fit like an inlay. Trying to avoid using the anterior region as much as possible, they used an "aerated bar" in this area.

The Brazilian, Benjamin Bello, worked on evolving satisfactory subperiosteal techniques, stressing that such implants were suitable only for the mandible. Boris Trainin of London also did numerous subperiosteal implants during the 1950's. His implants closely resembled in design those of American practitioners.

Other early implantologists working with subperiosteal implants were the American William Ogus, who in 1951 reported his attempts with upper and lower subperiosteal implants made from impressions taken directly on bone; the French practitioners Parant, Sabras, Mazotto, and Pierre Audoire; and the South American, la Rosa Werner (Fig. 5-92).

Fig. 5-92. A maxillary subperiosteal implant by LaRosa Werner. The implant has no extension across the hard palate and was inadequate as support for a full restoration. (Courtesy LaRosa Werner.)