10 Theories and techniques of oral implantology

Fig. 1-23. The teeth that will act as the anterior abutments for the fixed partial denture are prepared for full crown coverage. Tube impressions of them are taken, as well as the necessary bite registrations and an opposing jaw alginate impression. In addition, an alginate or rubber impression is taken of the tooth preparations, including the posterior edentulous area, in order to fabricate a temporary acrylic splint.

placement over the anterior tooth abutments and the posterior implants immediately after their inser-

tion (Fig. 1-24). Temporary crown forms are placed over the prepared natural tooth abutments, and the

patient is dismissed (Fig. 1-25).

Second visit. On the second visit, the veneer

crown castings are fitted over the prepared abutment teeth, properly balanced, and put aside. The

temporary acrylic splint is fitted and ground into proper occlusion. The original x-ray films (Fig. 1-26)

are checked for the best site and optimal depth of the implants, and the step-by-step installation pro-

cess begins.

   Using a No. 6 round bur or spear-point bur set in a contra-angle, the alveolar crest is penetrated slowly to a depth of 5 to 6 mm. (Fig. 1-27). An x-ray is taken to check the depth and the degree of parallelism between the crowns of the abutment teeth and the bur (Fig. 1-28). A second round bur is drilled into the alveolar crest slightly distal to the first round bur, which remains in position as a parallel guide (Fig. 1-29), then either one of the round burs is removed.

The helical bur is set into the contra-angle. At

this point the operator has a choice. If he prefers the "hollow-mill" technique   whereby a cylinder

of bone is left attached to the host   it is imperative
that the helical bur not go deeper than the

superficially set round bur. If he wishes to eliminate

Fig. 1-24. The temporary acrylic splint and metal copings for a porcelain-fused-to-metal bridge are seen here.

Fig. 1-25. The copings are placed over the prepared teeth.

the hollow-mill technique, the operator merely drives the helical bur to the full desired depth. It is assumed, however, that because one of the advantages of the vent-plant is its utilization of a bone core to promote more rapid securing of the implant, the operator will frequently choose to utilize this feature. If so, the specially designed trephine is used to penetrate the bone beyond the depth created by the helical burs.

When the mill is removed, either the cylindrical bone core remains attached to the host, or—as is often the case--it breaks away and can be found in-side the hollow mill. It is then removed from the mill and placed inside the vent. The vent-plant containing the cylinder of bone is then screwed into position. Because this procedure is slightly more compli-