can be shortened by cutting (24) a few millimeters off the legs. The altered legs should be retapered and smoothed (25).

Caution: After any form of alveoplasty, the implant site must be re-evaluated to ensure that a previously selected implant design is still appropriate.

Before final seating, the implant is tried in its socket and the alignment of its post checked with that of the neighboring teeth (26). Often the neck (27) must be twisted so that the post will follow the arch line. This is particularly important in anterior sites for the construction of a natural-looking, non-bulky restoration.

A single-headed inserting instrument is used with a finger sup-porting the labial plate. A few taps should sink the implant to its proper depth, with the bottom of its post touching the top of the ridge.

The single-tooth bladevent is the only bladevent design that must be immediately stabilized after insertion. The method of stabilization will depend upon its location, the condition of the neighboring teeth, and the type of final restoration.

The single-tooth implant can serve an important function when a maxillary canine is missing by insuring osteogenic stimulation within the canine pillar. This column of bone limits the anterior extent of the maxillary sinus. As the column shrinks, the sinus advances. Sinus advancement may threaten the bicuspids, particularly when the situation is aggravated by bone traumatized by drifting teeth.

The naso-mental crease also deepens as the underlying bone shrinks, making the lip drop in the area — a tendency noteworthy for its cosmetic implications. Thus an implant can provide more benefit than a conventional restoration whose prime functions are space maintenance and providing a chewing surface.

Anterior Tooth Replacements

The decision to use an implant in a one- or two-tooth anterior span depends primarily upon the condition of the remaining teeth and their supporting tissues. Neighboring teeth with good bone sup-port (1) are usually adequate anchors for a prosthesis without the use of an implant. An implant might be considered to promote osteogenesis, but in such a short span the neighboring teeth usually provide adequate stimulation.

Frequently the cause of tooth loss affects neighboring teeth as well, and they are either unstable or in a precarious situation (2). In such cases an implant can provide additional support for a

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