176 Theories and techniques of oral implantology

Fig. 5-81. Berman's circumferential wiring technique. A, The wire is passed through a double-tapered needle placed between the periosteum and bone on the buccal side of the mandible. B, The needle at the buccal lower border; C, the needle at the lingual lower border. D, The needle has been pushed along the entire lingual border of the mandible, disengaged from the wire, and the wire twisted. (From Berman, N.: Implant technique for full lower denture, Washington Dent. J. 19:15-17, 1950.)

Berman was also among the first to experiment with Ivalon-coated implants. Ivalon, a plastic sponge made of polyvinyl alcohol foam, had been buried by other researchers within the bodies of experimental animals. Upon removal of the implanted sponge, it was found to contain noninflammatory fibrous tissue. It was also discovered that Ivalon implanted under the periosteum and Ivalon heat-sealed to Vitallium and buried within tissues also became invaginated by fibrous tissue. Berman postulated that Ivalon around abutment posts would allow the tissue to adhere more readily, therefore preventing bacterial invasion of the implant site. However, the idea did not work. Microbes in the mouth found

Ivalon an ideal medium in which to rapidly proliferate. After repeated failures, Berman abandoned implants incorporating Ivalon.

How an individual implantologist modifies and perfects his ideas can be clearly seen in the work of Isaiah Lew. Lew, working in the late 1940's and early 1950's, refined his own basic implant design for a full mandibular restoration (Fig. 5-83). He reduced the bulk of his early latticed designs gradually until he developed a simplified modern design with fewer metal parts resting on bone. Lew's later implants had simple tapered abutments, and their components directed functional stress to cortical bone—the external oblique ridge, lingual bony plate,