Implant histology 85

sponds to the peripheral part of the studied material (Fig. 4-4). The tissues are made of a dense, fibrous, connective tissue, particularly in the region immediately adjacent to the hollow left by the metallic spiral itself. Circling this fibrous tissue, and always at some distance from the spiral, are osseous trabeculae, which differentiate directly from connective tissue.

At a deeper level, the hollow wire was enclosed by dense connective tissues of a fibrillar type (Fig. 4-5). In a different site, not in relation to the hollow left by the wire, granulation tissue with an infiltration of polymorphonuclear leukocytes, lymphocytes, and plasma cells was seen.

Further studies were done at various levels along the site. Most of these demonstrated bone in some state of transformation, and some showed evidence of inflammatory reactions characterized by abundant polymorphonuclear leukocytes and plasmocyte infiltrations. Sections made at a distance from the implant site contained richly vascularized tissues, constituted mainly of fibroblasts and some lymphocytic materials (Fig. 4-6).

From his observations, Zepponi concluded:

1. The embedded wire, being enclosed in a dense

fibrous connective tissue, does not provoke

intolerancy phenomena.

Fig. 4-6. At a distance from the implant, richly vascularized tissues containing fibroblasts and some lymphocytes are seen. (From Chercheve, R.: Les implants endo-osseux, Paris, 1962, Librairie Maloine.)

2. Ossification around the wire takes place only at a certain distance and with all the characteristics of metaplastic ossification. This is the same type of organization that takes place around an orthopedic screw completely em-bedded in tissue. In other words, a thin, soft tissue membrane always forms around a metallic pin, no matter in which part of the body it is implanted.

3. As for the inflammation, such a reaction may not be related to the implant itself. It may have been aroused by special conditions inherent to trauma, such as poor positioning of the implant in relation to the dental pros-thesis. This, of course, is caused by poor operative techniques.

Perron-Andres on a Formiggini type implant

The Spaniard, Dr. Carlos Perron-Andres, care-fully documented the case of a 27-year-old woman. Her family history indicated that her father died of a sarcoma, her mother was suffering from heart insufficiency, and two brothers had died of infectious diseases. One other brother was alive and well. The patient herself enjoyed good health, although as a child she had had chickenpox and, at the age of 20, had joint pains that returned from time to time for 2 years without preventing her following her normal daily routine.

On April 2, 1958, Perron-Andres extracted the first left upper premolar, prepared the socket with a surgical bur, and inserted a Formiggini type im-

Fig. 4-7. A Formiggini type implant inserted by Perron-Andres. The uppermost spirals were set too close to the alveolar crest, inviting failure caused by epithelial tissue invagination. (From Chercheve, R.: Les implants endoosseux, Paris, 1962, Librairie Maloine.)