342 Theories and techniques of oral implantology

Fig. 9-24. The taps are carefully screwed into the bone using a hand ratchet. (From Chercheve, R.: Les implants endo-osseoux, Paris, 1962, Librairie Maloine.)

in the area of the intended implant interventions. Then the anterior tooth abutment was prepared for a full coverage restoration. A modeling compound copper tube impression of the prepared tooth and a wax interocclusal record of centric relation were made. An alginate impression of the opposing jaw and an elastic impression of the prepared tooth plus the edentulous space were also made. The technician used these impressions to fabricate a veneer casting and a temporary acrylic splint to cover the natural tooth abutrnent and implant abutments immediately after insertion.

At the beginning of the second visit, just prior to insertion of the implants, the coping was fitted over the natural tooth abutment and its gingival, marginal, and occlusal relationships adjusted. The acrylic splint was tried in position and ground into proper occlusion. Its tissue-bearing surface was hollowed out in the area of the implants.

To insert the first implant, a No. 6 round bur was placed in a slow-running contra-angle with a water spray attachment. This tool was centered over the alveolar crest and used to drill directly through the mucoperiosteunr into the underlying bone until the bur was stopped by the built-in "stop guard" on its shaft. This first bur was left in position, disengaged, and radiographed for parallelism with the prepared coronal portion of the tooth abutment and for its proximity to the mandibular canal.

With the first bur in the alveolus as a parallel guide, a second round bur was drilled into the bone

Fig. 9-25. Both taps are parallel to one another and to the bicuspid preparation.

about 4 mm. behind it. Great care was taken not to perforate the buccal or lingual plates of bone. An x-ray was used to ensure this.

Leaving one of the round burs in position, the other was removed. A helical bone bur was drilled deeper through the same hole, making sure that it was parallel both mesiodistally and buccolingually with the prepared tooth and with the extended shaft of the round bur. Another x-ray was taken to reveal the depth of the helical bur, its proximity to the mandibular canal, and its degree of parallelism with the prepared tooth and round bur shaft.

The remaining round bur was removed, and the second helical bur was driven into the alveolus parallel to the shaft of the first helical bur and deeper than the hole created by the preceding round bur. An x-ray was taken to evaluate this.

One of the helical burs was then removed; in its place a tap, set in a hand ratchet, was screwed deep into the bone parallel to the remaining helical