Weiner, Saul; Aboyoussef, Hoda; Zweig, Barry; Thompson, Van: University of Medicine & Dentistry of New Jersey, 110 Bergen Street, University Heights, Newark, NJ, 07103, USA
Kwan, Norman; Yang, Silvia: Canadian Dental Implant Institute, 206 King Street, St. Catharines, ON, L2R 3J7, Canada

Abstract:

Most dental implant systems today employ either an external or internal hexed implant which connects to an abutment using a screw for stabilization of a prosthesis. This report reviews the success of a one-piece implant system with a 3mm extended hex to which the prosthesis can be directly attached, either with a screw or by cement.

In one series, a total of 172 consecutive patients with more than 800 implants were evaluated with one group receiving the two-piece device in a two-stage procedure while the second group received a two-piece device in a one-stage procedure. Eight year Kaplan-Meier life table analysis indicated no significant difference in survival between the two-stage (91.6%) and the one-stage (89.7) protocols, p<0.05.

In another one-year prospective clinical study, 140 (88.61%) of the one-piece non-submergible, implantable devices achieved osseointegration and were able to support a total of 64 fixed restorations. 20 out of 32 single implant restorations were screw-retained crowns the other 12 single crowns were cemented. 32 other restorations were supported by multiple implants and all were screw retained. No prosthetic complication was observed in this one-year period.

This 3mm extension provides stable support in lateral function and retention of the final prosthesis - no separate abutment was used. The abutment-implant component gap is replaced by a smooth-rough interface. The removal of the component gap eliminates all prosthetic complications. In addition, the location of the smooth-rough (abutment-implant) interface minimizes horizontal and vertical bone loss around implant support of the prosthesis.

Use of this one-piece system eliminates problems associated with impression transfer of the two-stage external hex and the uncertainties in selection and use of abutments. In addition, the lack of an abutment-implant component gap reduces prosthetic instability, reduces the possibilities of loss of crestal bone adjacent to the abutment-implant interface and the possibility of component fracture.

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2. Hermann JS, Cochran DL, Nummikoski PV, Buser D: Crestal Bone Changes Around Titanium Implants. A Radiographic Evaluation of Unloaded Nonsubmerged and Submerged Implants in the Canine Mandible. J Periodontol 1997;68:1117-1130.

This research is supported by Biomedical Implant Technology Inc.