174 Theories and techniques of oral implantology

Fig. 5-77. Berman's meshwork subperiosteal implant was fashioned on a stone model prepared from a direct impression of the bone. (From Berman, N.: An implant technique for full lower denture, Dent. Dig. 57 [10] :438, 1951.)

Fig. 5-78. Because it was prepared from a direct impression of the bone, Berman's meshwork implant closely fitted the bone. (From Berman, N.: An implant technique for full lower denture, Dent. Dig. 57 [10] :438, 1951.)

niques. Their early technique, described in the early 1950's, consisted of taking a full lower impression of the soft tissues covering the underlying bone of an

endentulous jaw.* They then estimated the thickness and character of the mucosa overlying the bone by

*Gershkoff, A., and Goldberg, N.: Further report on the full lower implant denture, Dent. Digest 56:11, 1950.

x-rays and palpation and scraped down the stone model accordingly. From this modified model they prepared a Vitallium cast (Fig. 5-74). The tissues over the bone were then reflected and the implant fitted on the exposed bone and held in place with screws (Fig. 5-75).

Some of the early Goldberg-Gershkoff designs failed. Because of the extreme difficulty in determining the true character of the bone without reflecting the overlying tissues, the implants did not fit properly. Also, because the implant sat right on top of the jaw's crest with no buccolingual extensions, the screws were not adequate to prevent implant dislodgment by rocking motions of the jaws during mastication. The screws became loose and were ex-foliated, and the implant failed.

Recognizing that a flat metal strip held in place by screws was easily dislodged, Gershkoff and Gold-berg designed a more elaborate implant with lingual extensions (Fig. 5-76). This design was also prepared on a model, not from a direct bone impression. Again, because of poor fit over the bone, the implant tended to fail but still could remain in the mouth for many years.

Later in 1952, by altering both their designs and operative procedures, Gershkoff and Goldberg began performing successful subperiosteal implant interventions.