Endodontic implants 587

interdental length of the implant has been established and the implant is withdrawn.

Fifth, rotary burs are used to pierce the apex, which is enlarged until the pin or post can pass through. Enlarging the apical foramen removes a great deal of cementum. This cementum is particu-

larly prone to infection and, by destroying it, the danger of a later infection is greatly diminished. Because this stage shortens the root about 1mm., it is a kind of "inner apicoectomy." The burs pass into the bone, gradually deepening the bore' hole as much as anatomically possible and

Fig. 13-9. Orlay's eight-stage endodontic pin insertion procedure.

1. The root canal is trephined and the entrance made funnel-shaped for easier access.

2. The canal is widened, stopping just short of the apex, which has been filled with Kri paste to avoid contamination with debris.

3. With Kri paste in the apex, the root canal is enlarged to the diameter of the pin. At this point, the apex is still unpierced.

4. The pin is inserted and its emergence point marked. This establishes the intradental depth of the pin.

5. The apex is pierced and enlarged. The bone is prepared for the pin gradually, deepening and enlarging the site. Roentgenographic control is essential. The post is inserted and its new emergence point marked.

6. The pin is withdrawn, and hemorrhaging is arrested. The pin is deeply notched.

7. After the canal is cleaned and dried with ether, Kri paste is applied to the apices of both the canal and the pin and cement applied to their respective superior portions. The pin is then inserted.

8. The excess length is snapped off and any remaining space treated. The implanted tooth is then immediately stabilized. (Redrawn from Orlay, H. G.: Endodontic implants, J. Oral Implant Transplant Surg., pp. 44-53, 1965.)