114 Theories and techniques of oral implantology

In another case in which an internally threaded vent-plant was used, a specimen for examination was obtained under the following circumstances. The vent-plant was placed in the maxilla just below the nasal septum. Approximately 8 months after its insertion the impl ant broke in two (Fig. 4-64). The shaft portion was removed by screwing it counter-clockwise, leaving the apical ring still in the bone (Fig. 4-65). When the vertical portion was surgically removed, it contained bone (Fig. 4-66).

Blakey on metallic and nonmetallic implants

Katus K. Blakey, 1).1).S., of Howard University, Washington, I). C., experimentally inserted solid shaft threaded implants, vent-plants, and nonmetallic crystalline bone screws into the mandible and maxilla of dogs. The insertion techniques followed

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those of Linkow. Six months after implant insertion, the animals were sacrificed.

All the metallic implants were separated from the bone by a fibrous tissue membrane (Fig. 4-67). The bone was dense, with numerous osteocytes, and there was no sign of inflammation of either the fibrous tissue membrane or the bone (Fig. 4-68). Near the base of the implant the formation of blood vessels was evident (Fig. 4-69). Also, the fatty mar-row tissue looked normal. In another view of the base of the implant the organization of the connective tissue and blood vessel formation are clear (Fig. 4-70) .

Blakey also examined the tissue found inside the vent of a vent-plant (Fig. 4-71). It was partly fibrous and contained a good amount of healthy bone.

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Fig. 4-68. Under higher magnification, osteocytes can be seen in the bone and osteoblastic activity around the periphery. Note the absence of inflammatory activity. (Courtesy K. R. Blakey, Howard University.)