Osseodensification: An Overview of Scientific Rationale and Biological Background.

In implant dentistry, primary mechanical stability is considered a prerequisite for successful osseointegration. That is, the alveolar bone architecture of the implant drilling site is critical in dictating the success rate of the implant. Immediately after implant placement, a series of cellular and molecular events occur directly on the implant surface (apposition), whereby host tissues biologically integrate the "foreign" biomaterial into the native bone structure. While cortical bone is responsible for providing the function of withstanding torsional loading and enabling high initial implant stability, cancellous bone is richer in cellular content and is vasculature and, therefore, capable of supplying progenitor cells more rapidly to the implant surface. This article provides an overview of the basic biological remodeling events that take place following implant placement and outlines surgical methods used over the years to increase primary implant stability. Thereafter, implant loading protocols utilizing low, high, and excessive torque are discussed. Finally, the authors introduce the biological rationale supporting the concept of osseodensification of osteotomy sites, which have been heavily utilized in modern implant dentistry.