Platform switching: a new concept in implant dentistry for controlling postrestorative crestal bone levels.

TLDR

Histologic and radiographic evidence shows that a biologic dimension of hard and soft tissues extends apically from the implant‑abutment interface, with vertical bone repositioning and soft tissue attachment occurring when the implant is uncovered and matched‑diameter components are attached, and that conventional two‑piece systems place the interface at the outer edge of the platform. The article introduces platform switching and establishes a foundation for understanding its biologic and clinical implications. Wide‑diameter implants were initially restored with standard‑diameter healing abutments and prosthetic components, creating a mismatch between implant and abutment platforms. Long‑term radiographic follow‑up shows that platform‑switched wide implants exhibit reduced vertical crestal bone loss compared to conventional restorations, indicating that inward repositioning of the interface alters the post‑restorative biologic process.

Abstract

Histologic and radiographic observations suggest that a biologic dimension of hard and soft tissues exists around dental implants and extends apically from the implant-abutment interface. Radiographic evidence of the development of the biologic dimension can be demonstrated by the vertical repositioning of crestal bone and the subsequent soft tissue attachment to the implant that occurs when an implant is uncovered and exposed to the oral environment and matching-diameter restorative components are attached. Historically, two-piece dental implant systems have been restored with prosthetic components that locate the interface between the implant and the attached component element at the outer edge of the implant platform. In 1991, Implant Innovations introduced wide-diameter implants with matching wide-diameter platforms. When introduced, however, matching-diameter prosthetic components were not available, and many of the early 5.0- and 6.0-mm-wide implants received "standard"-diameter (4.1-mm) healing abutments and were restored with "standard"-diameter (4.1-mm) prosthetic components. Long-term radiographic follow-up of these "platform-switched" restored wide-diameter dental implants has demonstrated a smaller than expected vertical change in the crestal bone height around these implants than is typically observed around implants restored conventionally with prosthetic components of matching diameters. This radiographic observation suggests that the resulting postrestorative biologic process resulting in the loss of crestal bone height is altered when the outer edge of the implant-abutment interface is horizontally repositioned inwardly and away from the outer edge of the implant platform. This article introduces the concept of platform switching and provides a foundation for future development of the biologic understanding of the observed radiographic findings and clinical rationale for this technique.