470 Theories and techniques of oral implantology

8. Determining the most advantageous position for the implant is much easier because the under-lying bone is always exposed during insertion. In the case of a post type or pin implant, the bone is usually not viewed directly because the tissues are not necessarily retracted. Thus the implant may

Fig. 11-21. Horizontal and vertical set screws inside the posts may give added stability in affixing the prosthesis. (Courtesy Park Dental Research Corporation.)

terminate out of the bone rather than well within it.

9. In porous areas, such as the maxillary tuberosity, the blade implant is by far the most advantageous because of its width. Several screw type implants have actually fallen into and through porous areas, thereby injuring vital structures. However, the anteroposterior width of the blade with its characteristic wedge design becomes an extremely strong abutment where it is wedged into the porous bone. Therefore it is almost impossible to drive a blade deeper than its superoinferior height, no matter how porous the bone may be.

10. A blade implant can be placed into a knife-edge ridge. No other type of implant can be used in such a ridge without perforating the cortical plates of bone flanking the ridge (Figs. 11-18 and 11-19).

11. It is not absolutely necessary to splint a blade implant immediately after its insertion, as must be

Fig. 11-22. A to D, For dense bone the apical end of the blade should be open. E, A Panorex showing open-ended blades for dense and deep bone.