Subperiosteal implants 579

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ATYPICAL SITUATIONS

Because of improper instructions given to the laboratory technician, a subperiosteal implant can sometimes be cast with an extremely long neck at the expense of a shorter post. This creates not only a looser fit of the superstructure but also causes a weak link in the implant framework in the area of the lengthened neck.

Such a case occurred with one of Linkow's patients. The unique ingenuity in step-by-step procedures for restoring the arch is shown in the following illustrations.

The neck of the left anterior post broke, leaving only three posts connected to the substructure (Fig. 12-121, A). Notice that acrylic resin was added

Fig. 12-122. The mesostructure was cemented over the four implant posts.

around the long neck of the right anterior post, which aided in retention for the superstructure as well as strengthened the extra long neck. A single tooth blade implant was then tapped into a groove previously prepared in the bone in the same area where the neck had broken. The blade was set into the bone between the buccal and lingual peripheral struts (Fig. 12-121, B) . The tissues were sutured close to the neck of the blade (Fig. 12-121, C).

After 5 or 6 days the sutures were removed. When healing had been completed, a hydrocolloid impression was taken of the four posts and a wax interocclusal record of centric relation was obtained. An alginate impression of the upper denture was also taken.

The casts were articulated and a mesostructure containing four gold copings soldered to one another with a dolder bar was fabricated. A new implant

Fig. 12-123. The lower implant denture with its internal clip bar attachments was placed over the mesostructure and articulated with the maxillary denture.

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