Dr. Alan MeltzerFROM THE DESK OF ALAN M. MELTZER DMD MScD
This monograph will address crestal bone preservation techniques. As I discussed in my last newsletter, when an implant is exposed to the oral environment there is a natural adjustment in the position of the crestal bone. The bone adjusts apically and laterally about 1.5 millimeters. This has been classically described as bone loss to the first thread. As discussed previously, this natural phenomenon impacts soft tissue morphology and aesthetics.
Pic1One way to overcome this problem is through the use of platform switching. Platform switching is defined as the placement of an undersized prosthetic component on an oversized or expanded platform.
Pic2Notice the classic formation of biologic width on the mesial implant. Bone remodeling has moved the point of bone to implant contact to the first thread. Note how the bone level on the distal implant holds at the platform level due to the impact of platform switching on the formation of biologic width.
How does platform switching alter the formation of biologic width?
By moving the implant abutment junction away from the edge of the implant, a space is provided to shield the bone from the inflammatory process associated with the junction. This physiologic inflammatory process has been described and documented by Ericsson and others. It is this inflammatory reaction which is the trigger for the formation of biologic width. Platform switching provides a space for the inflammatory cells to reside without impacting the bone. Therefore, platform switching eliminates crestal bone remodeling, providing additional bone to implant contact and eliminating changes in soft tissue morphology usually associated with the formation of biologic width.
pic3The classic location of the inflammatory cells.
Pic 4The location of inflammatory cells with platform switching. Note how the platform provides a space for the inflammatory cells so it does not impact the crestal bone.