Procera® Abutments

Abstract: The purpose of this study was to measure the tensile bond strength of Procera® AllCeram copings cemented onto Procera® Custom titanium abutments with varying taper and/or abutment heights and using a eugenol provisional cement. Procera custom abutments were fabricated using the Nobel Biocare 3D CAD/CAM program. The abutments were designed in 4.0 and 8.0 mm heights. With the height held constant at 4.0 mm, abutments were designed with 3.9° and 8° tapers. Similarly 3.9° and 8° tapered abutments were designed in the 8.0 mm height. The four (4) Procera custom abutments were scanned by the Procera scanner and Procera aluminum oxide copings of 0.6 mm thickness were fabricated by Nobel Biocare, AB for each abutment. The Procera custom abutments were positioned onto 3.75 Brånemark implants and tighten using Unigrip® abutment screws. The implant/abutment sample was positioned within a Universal Instron testing machine. A Procera aluminum oxide coping was cemented onto the abutment using the provisional cement Temp Bond NE. A load was applied by the Instron machine to the Procera coping to measure the tensile strength needed to remove the aluminum oxide coping from the titanium abutment. All four implant/abutment/coping samples were test in this manner. A significant difference (P=0.001) was demonstrated when the 4.0 mm abutment height (9.166 kg) was compared to the 8.0 mm abutment height (34.55 kg) with the abutment taper held constant at 3.9°. A significant difference (P=0.001) wad demonstrated when the 4.0 mm abutment height (6.69 kg) was compared to the 8.0 mm abutment (30.21 kg) with the abutment taper held constant at 8°. A significant difference (P=0.01) was demonstrated when the 3.9° abutment taper (34.55 kg) was compared to the 8° abutment taper (30.21 kg) with the abutment height held constant at 8.0 mms. A significant difference was not demonstrated (P=0.14) with the 3.9° tapered abutment (9.16 kg) compared to the 8° abutment taper (6.69 kg) with the abutment height held constant at 4.0 mm.
Conclusions: Increasing the abutment height will result in an increase in the force needed to remove an aluminum oxide coping from the titanium abutment, while increasing the abutment taper will result in a decrease in the force to remove the aluminum oxide coping.

Abstract: The advantages of the custom design of the CAD/CAM Procera® abutment warrants its evaluation for fit with the most commonly used implant systems. If a precise fit can be achieved between the hexagons of these implants and the hexagon of the Procera abutment, then this abutment could be considered as a universal abutment for these implant systems. Six implants were obtained for each of the following implants systems. Brånemark - Conical Self-Tapping 3.75 X 10 mm implants, Implant Innovations Inc (3I) - 3.75 X 10 mm implants, Impla-Med - 3.75 X 10 mm implants, Paragon - Taper-Lock 4.0 X 10 mm, Lifecore - Restore 3.75 X 10 mm implants. The three-dimensional external hexagon of each implant was measured, as was the internal hexagon of six Procera custom abutment blanks. Procera abutments were fabricated from Procera blanks and fitted onto the implant abutments. The appropriate abutment screw was used for each implant system to tighten the abutment using an electric torque controller (Nobel Biocare AB, Göteborg, Sweden) and tightened to 32 Ncm. Following tightening, the junction of the abutment to the implant was photographed. Each sample was positioned in a holding device oriented perpendicular to the long axis of a radiographic source and radiographs were made. The mean hexagon dimensions for the implants were: BrOEnemark Conical Self-Tapping 3.75 mm implant (2.69 mm widths and 0.70 height), Implant Innovations Inc (3I) 3.75 mm implant (2.69 mm widths and 0.70 height), Impla-Med 3.75 mm implant (2.69 mm widths and 0.69 height), Paragon Taper-Lock 4.0 mm implant (2.69 mm widths and 0.79 height), and Lifecore Restore 3.75 mm implant (2.67 mm widths and 0.81 height). The mean hexagon dimensions for the Procera custom abutment internal hexagon was (2.73 mm widths and 0.90 mm height). The photographs of each sample demonstrated a clinically acceptable fit between the abutment and the implant. The radiographs demonstrated that the implant screws in many instances were not properly seating within the internal screw bore of the custom abutment. The dimensions and design differences of the screw heads would not permit proper seating of the screw head onto the clamping ledge of the abutment bore. A preliminary examination of the fit of the Procera abutment screw (Unigrip screw - Nobel Biocare AB, Göteborg, Sweden) used to replace the abutment screw of each implant system demonstrated that all of the non-Brånemark implants appeared to accepted the Unigrip screw into the internal screw bore of the implant.
Conclusions: From the measurement data it would appear that the Procera abutment would fit onto all of the implants measured in this study. However the Procera abutment would not accept the non-Brånemark implant abutment screws. Although all of the non-Brånemark implants appeared to accept the Unigrip screw into the internal screw bore of the implant further studies are needed to confirm a precise fit.