Prevail_Clinical_Indications

We recently published a paper discussing the theory behind and some clinical findings relating to the concept of Platform Switching.1 This paper discusses some of the dental literature describing the dynamics of biologic width development around implants. Platform Switching is defined as a protocol that includes smaller diameter restorative components that have been placed onto larger diameter implant restorative platforms, i.e., a 4.1mm diameter abutment on a 5mm diameter implant (Figure 1).

The concept of Platform Switching is unique to the BIOMET 3i Implant System since it is the only major system with uniform hex and screw sizes for implants greater than 3.75mm in diameter. This provides maximum flexibility to surgeons and restorative dentists in that the surgeon can choose to platform switch at the time of implant placement. With the BIOMET 3i System, it is up to the surgeon and/or restorative dentist to choose the configuration of the interface and the dimension of the abutments in relation to the size of the restorative platform of the implant. Other systems force the clinician to use abutments that match the diameters of the implants.

Platform Switching has provided clinicians with many benefits and has been used to improve treatment outcomes for some time. This protocol evolved anecdotally when wide diameter implants were first manufactured and placed in 1991 and the corresponding restorative components were not yet available. The dimensional mismatch between implants and restorative components created either a 0.45mm (4.1mm prosthetics/5mm implant platform) or a 0.95mm (4.1mm prosthetics/6mm implant platform) circumferential horizontal difference in dimension between the implant seating surface and the abutment restorative platform. In the publication noted above, bone loss at up to 10 years post occlusal loading was significantly less in and around the implants with Platform Switching than one would have expected to see with conventional implant restorations (bone loss to the first thread). The prevailing theory as to why Platform Switching decreases bone loss is that by moving the implant/abutment junction medially on the implant restorative platform, the overall effect of the abutment inflammatory cell infiltrate (ICT) may be reduced and thus decrease the resorptive effect on the adjacent crestal bone.

There are numerous clinical benefits to Platform Switching including:

Optimal management of the prosthetic space—the amount of restorative volume available for an optimally contoured, physiologic implant restoration;
Improved bone support for short implants—bone remodeling around a platform switched implant is minimized, therefore there is potentially greater bone/implant contact for short implants, thus opening the possibility of treating more patients with less extensive therapy;
Potentially preserving bone that supports the overlying soft tissue—less recession of the interdental papillae and facial gingival margins for optimal aesthetics, especially in the anterior aesthetic zone.

Optimal management of the prosthetic space and correcting implant positions with Platform Switching provides significant flexibility for clinicians. Platform Switching can reduce the cervical diameter of the restoration, relative to the size of the implant, when surgical requirements dictate a wide diameter implant (ie, extraction site, immediate implant placement) but the prosthetic space demands a smaller size for the restoration.

Despite the benefits of Platform Switching, there are potential technical drawbacks i.e., confusion in the dental laboratory when ordering restorative components. If implant clinicians wanted to platform switch, precise instructions had to be written for dental laboratory technicians for implementation of the protocol. Often, this would result in multiple communications between restorative dentists and technicians until the proper components were ordered and implemented. The color coding that was an integral part of the OSSEOTITE® Certain® Implant System would not be applied by the clinician in order for Platform Switching to occur. Also, Platform Switching could not be performed on standard diameter (4mm) implants. Currently available implant systems do not offer smaller diameter restorative components for standard implants with a 4.1mm restorative platform, as the wall thickness of the abutments would be too thin to accommodate the diameter of the abutment screw.

		Figure 1