Operative tips 265

Fig. 7-15. A specially designed calibrated periodontal pocket probe can be used to measure socket dept. (Omni-Depth Instrument, manufactured by Whaledent Inc.)

Fig. 7-16. A, If the abutment post of a post type implant is too long, it should be ground with a heatless stone with water attachment or a carborundum disk with water attachment. B, It is essential to hold the implant with pliers during this procedure.

should be determined by x-rays of the tap in position and by checking the occlusal clearance of the tap by having the patient close in centric position.

While the second tap is still in its osseous position, certain measurements can also be taken with a calibrated compass and etching needles. First the height of the tap above the soft tissue is taken. The tap is then removed and the intratissular part of the tap is measured with the compass outside the mouth (Fig. 7-14) . This measurement may be marked on the implant with the etching needle. When dealing with the spiral-post implant, it is usually a good idea to subtract the length of one spiral from the total intratissular length because it may not be possible to fully insert the last spiral in the socket.

Another very accurate way of assuring an appropriately long implant is to measure the socket depth with a specially designed and calibrated periodontal pocket probe* (Fig. 7-15) .

If, despite all previous measurements, a spiral-post implant is too long, a lower spiral may be cut off. If either a spiral-post or vent-plant implant has too long an abutment post, it should be disked off before insertion. If the implant has already been inserted, it is usually better to remove the implant before shortening its shaft. However, the operator may choose to shorten the shaft in the mouth. In this case his assistant should tightly grip the shaft of the implant with a thin, flat-nose pliers against the gingival tissues while the operator uses a heat-

*Omni-Depth Instrument, manufactured by Whaledent Inc., 304 Ashland Place, Brooklyn, New York.