CHAPTER 9 Mandibular endosseous

implant interventions

A great range of endosseous implant techniques can be used in the mandible. Not only may the type of implant itself vary, but the method of insertion and fabrication of a restoration may differ considerably from case to case.

Assuming that the patient's health is good, the prime consideration when contemplating an endosseous implant is the amount of alveolar bone, its shape, and its condition. When a good amount of alveolar bone exists between the alveolar crest and an an-atomic landmark, post type implants can be used. Pin implants are most beneficial when used to circumvent various anatomic landmarks, where less bone structure is available. Knife-edge ridges re-quire either narrow ridge implants or the newly designed blade-vent. Because the blade-vent implant has an even wider range of application, it will be dealt with in a separate chapter.

The material presented here shows the various situations in which vent-plants, spiral-shaft implants, triplants, and some of the other more common endosseous implants can be used.

UNILATERAL RESTORATIONS

To evaluate a unilateral edentulous area, intraoral, periapical radiographs are taken of the intended implant sites. These studies should include the entire edentulous free-end saddle area; a fairly clear picture of the mandibular canal, especially its superior wall: the two anterior teeth closest to the edentulous area intended as natural tooth abutments; and the mental foramen, if it is included in the edentulous area. If implants are to be used in the area of the mandibular canal, a Panorex or a lateral plate roentgenogram should also he taken to determine the outline of the canal.

Case 1

Unilateral posterior free-end saddle restoration using vent-plants and a temporary splint

In this first case two implants and two natural teeth constituted the supports for a four-unit fixed partial denture. The type of implant used, the Linkow vent-plant, is a modified post with an opening at its base through which hone can possibly grow (Fig. 9-1) . This implant, like any other post implant, must be used only when there is sufficient alveolar bone in which to bury the implant's spirals and a good portion of its narrower shaft. Because the implant comes in several lengths with a variable number of spirals, it has a wide range of applications.

The two anterior tooth abutments were prepared for full coverage restorations (Fig. 9-2). Modeling compound in copper tube impressions, as well as a wax bite, were taken. In addition, an alginate impression was taken of the two prepared natural tooth abutments along with the edentulous spaces and of the opposing jaw. These impressions were used to fabricate two veneer castings and a temporary acrylic splint to cover the prepared natural teeth and implant abutments. Such a splint is used immediately after implant insertions to help stabilize them and to protect the tongue, cheeks, and lips from laceration by the sharp line angles of the protruding implant posts (Fig. 9-3) .

At the beginning of the second visit, just prior to inserting the implants, the castings were fitted over the natural tooth abutments (Fig. 9-4) . Their gingival

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