and coronal (4) cross-sections show that an implant set in this fashion has good bony resistance to lateral forces.

The implant site also can be angled across the arch (5). Pro-file (6), saggital (7), and coronal (8) sections indicate adequate bony support in this position.

Even when the implant is set across the dental arch line (9), the sections (10, 11, 12) show secure encasement by bone.

Seating the narrow single-tooth implant is unique in several ways. Because the post obscures the shoulders, the pointed seating instrument cannot be used on them. Thus, the force must always be directed on the post, a problem with an implant whose post has been acutely angled away from the socket's angle. In such a case, bending the post is delayed.

With a single-head seating instrument, the implant — with its post not yet bent — is driven almost all the way home.

Caution: The socket is always made to its full depth, even when the bone is porous, to minimize off-center seating problems.

The implant is then removed and the neck is bent appropriately. When countersinking is necessary, it is accomplished prior to re-insertion, although in experienced hands it does not matter.

The implant is returned to its socket, and the single-headed seating instrument is used again to tap it home. Because the force is being directed against the labial plate by using the angled post, the labial plate should be supported.

Caution: Because of the implant's narrowness, it is easy to create a "drag" (13) on the implant with a supporting finger. The fingers should not press the implant or inserting instrument during seating.

If the deeper bone is exceptionally dense, the legs of the implant can be shortened. The cut edges should be reground to a taper to facilitate insertion. When the post is only slightly misaligned after insertion, it may be trimmed in the mouth with a bur or stone (14) to be parallel with other abutments and perpendicular to the dental arch. Water (15) must be used continually to cool the post; metal is an excellent conductor of friction-induced heat.

Excessive trimming of the post in the mouth will reduce its height and/or width, and therefore its effectiveness as a support. Major alterations should be done outside the mouth prior to final seating. In most cases, the ability to bend or twist the neck of the post obviates the necessity for extensive remodeling of the post with burs.

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