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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This research is supported by Biomedical Implant Technology Inc.