Implant histology 113

onstrates active haversian systems and marrow spaces of variable size which contain fibrovascular tissue [Fig. 4-59].

Miscellaneous cases. As anchorage for a five-unit fixed partial denture, two non–self-tapping vent-plants were placed into the lower left molar area (Fig. 4-60). One of the implants was causing inter-

Fig. 4-65. The shaft portion was removed by unscrewing it, leaving the vent portion in bone.

mittent pain because of its proximity to the inferior alveolar canal and had to be removed.

A spicule of bone was tenaciously bound to the removed implant both by its close adaptation to the implant's overall length and by a bony growth through the vent portion (Fig. 4-61).

According to Harry Lane Robinson, M.D., of New York University School of Dentistry, the histologic report on sections of the specimen revealed in cross section that a band of dense fibrous tissue encircled the implant and was attached at the periphery to portions of dense bone (Fig. 4-62). A longitudinal section showed healthy living bone around the implant site (Fig. 4-63).

X

cal

Fig. 4-66. The surgically removed apical ring shown here with the rest of the implant contained bone.

Fig. 4-67. Under low power, a longitudinal section from a bone block around a metallic implant shows dense bone separated from the implant site (X) by a fibrous tissue membrane. (Courtesy K. R. Blakey, Howard University.)