Two-piece occlusion rim for screw-retained implant prosthesis.

The record base for a multiple, implant-supported, fixed prosthesis may be attached to the implants by screws. The screw attachment provides a stable record base for recording maxillomandibular relationships. Extraoral adjustment of the occlusion rim requires that it be unscrewed to allow removal from the mouth. The rim must be reattached with screws for the next intraoral evaluation. Although this cycle of removal and replacement provides stability, retention, and accuracy, it is time-consuming and inefficient. To resolve this problem, a two-piece record base/occlusion rim can be used. The screw-retained record base remains intraoral for the duration of the clinical appointment. The occlusion rim is designed to fit over the record base, with retention and stability, without screw retention. Use of the two-piece record base/occlusion rim facilitates convenient removal, adjustment, and replacement of the occlusion rim.

Controlled retainer-screw access placement for screw-retained implant prosthesis.

An implant-supported prosthesis is often secured to the underlying gold cylinders by retaining screws. There must be access to these screws from the oral surface of the prosthesis. Conventional preparation of this access is from the oral surface. This approach is difficult because the underlying gold cylinder is obscured. It may be damaged by a rotary cutting instrument as the access is prepared above it, because the cylinder cannot be seen during the preparation. Alternatively, the access hole may be unnecessarily enlarged in an attempt to find the cylinder. This loss of structure may weaken the prosthesis. A new approach, using 18-gauge stainless steel wire as a rotary cutting instrument, permits preparation of the access chamber from the intaglio surface of the prosthesis. This reduces risk of damage to the gold cylinder and is less destructive to the overlying material.

The use of attachments in combination implant and natural-tooth fixed partial dentures: a technical report.

When implants and natural teeth are combined, forces on the abutments need to be controlled so that neither the teeth nor the implants sustain excessive amounts of force. The technique described addresses reduction of potentially harmful cantilever effects in a fixed prosthesis that is facultatively removable. A nonrigid attachment is used in the implant crown. Telescopic copings are definitively cemented on the natural teeth. Provisionally cemented overcastings incorporate this nonrigid connection between the pontics and the implant crowns. The means of connection employs a semiprecision attachment in which the female connector is placed within the relatively immobile implant crown. The male connector is placed on the pontic seating into the implant crown. This relationship limits cantilever forces exerted on the natural-tooth abutment. The nonrigid connection of the tooth-supported retainer limits cantilever forces and directs occlusal loads axially in a direction along the long axis of the implant. This arrangement is acceptable as compared to the complete tooth-supported arrangement described by Shillingburg; in this situation, the implant will not migrate. Since 1986, this arrangement has been used clinically without attachment migrations, implant failure, or endodontic therapy, with only minor screw-loosening episodes.