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.