Endosseous blade implants 493

rapid resorption over ten other implant materials.

Some investigators claimed plaster of Paris, when in closed sterile wounds, showed little osteogenic capabilities. However, further investigators have de-scribed plaster of Paris to be of great value not only because of its osteogenic potential but also as a space filler that reduces the chances of secondary infection by discouraging epithelial invagination into the sockets and permitting connective tissue regeneration.

Also, although still no substantiation has been shown, it is believed that plaster of Paris releases calcium and phosphorus ions that participate in bone metabolism. All investigators agreed that there were no adverse inflammatory responses to plaster of Paris implants when used in tissue wounds.

Most cases reported on the use of plaster of Paris, including almost one hundred by Linkow, have shown little or no postoperative swelling or pain and no secondary infections. Plaster of Paris seems to

have a resorption characteristic that is compatible with the rate of new tissue replacement.

Although it is still not completely known, the length of time required for the complete resorption of plaster of Paris in a surgical wound from radiographic interpretation was from 3 to 5 weeks, ac-cording to Bier.

This next case illustrates a dental application.

The patient, a healthy 55-year-old woman, was suffering from a complete breakdown of her upper and lower dentitions, which were supported with two full arch porcelain-baked-to-metal splints. Large radiolucent areas appeared beneath the apices of all her lower teeth (Fig. 11-98), and a great deal of mobility and gingival recession were evident (Fig. 11-99).

With great care the entire lower bridge was disked away from the remaining teeth. These teeth were all so loose that they could be extracted with a slight tug of the fingers. However, even though there was a

Fig. 11-98. Preoperative radiographs. Note extreme bone loss in mandible and maxilla.