Platform shifting, or platform switching, is a concept that has come into the mainstream as it has become an integral feature of some of Nobel Biocare’s most popular implants.
Originally described by Dr. Lazzara, platform shifting is a concept that involves an inward horizontal repositioning of the implant-abutment interface (figure 1). This connection shifts the perimeter of the implant-abutment junction towards the center of the implant, creating a horizontal component for the total linear distance between the abutment and crestal bone required for biologic width.
This allows for higher tissue volume and vascularization, ultimately leading to more stable crestal bone heights and interdental papilla.
Less bone loss and better soft tissue support
Most studies show that a horizontal component of about 0.5 mm results in significantly less radiographically detectable crestal bone loss and better soft tissue support in the esthetic zone. Platform shifting can be accomplished with the NobelReplace Platform Shift tri-channel (figure 2) or NobelReplace Conical Connection (figure 3), which is identical to the NobelActive configuration.
I have had the good fortune to be able to place both the NobelReplace Platform Shift and Conical Connection implants during the pre-launch and evaluation stages. To date, our practice has placed over one hundred of these implants and have found the marginal bone levels and soft tissue esthetics to be excellent.
The surgical placement and instrumentation is virtually identical to the standard NobelReplace system, making it ideal from a staff training and surgical armamentarium standpoint. A simple case illustration will demonstrate the ease of use and predictability.
Platform shifting in practice
The case illustrated in this page is of a 78-year-old man who had a vertical and horizontal fracture through tooth #9 (FDI 21), evident clinically and on the pre-op film (figures 4 and 5). The treatment plan was to remove #9 and to immediately place a NobelReplace Platform Shift with immediate load.
This implant was chosen to maximize soft tissue volume in hopes of overcoming any negative tissue influences from a large maxillary frenum. The tooth was atraumatically removed and a surgical guide was fabricated to assist with depth placement of the implant.
The osteotomy was started with twist drills, but finished with osteotomes to preserve the buccal plate. A 5 x 13 mm NobelReplace Platform Shift implant was placed using the 4.3 mm implant driver, placing the implant to just below the facial height of the crestal bone to take full advantage of the platform shift.
A 6 x 3 mm healing abutment, 4.3 series was placed on the implant (figure 7), and the patient was then seen by his restorative dentist for immediate temporization (figure 8).
Superior esthetic results
The patient functioned on the immediate temporary for 12 weeks, at which time the final impression was taken (figure 9). Note that at all times the integrity of the marginal bone was preserved.
A CAD/CAM custom abutment was fabricated using the NobelProcera Scanner and Software (figure 10).
The final crown was inserted at 14 weeks (figure 11). As can be seen in the final restoration (figure 12), tissue level integrity is preserved.
Our practice has acquired a great deal of experience with NobelReplace Platform Shift and Conical Connection implants over the past year. We have seen superior esthetic results with excellent preservation of soft tissue and crestal bone. Although the follow- up period is relatively short, preliminary results are very encouraging. This is an excellent addition to the Nobel family of implant products.