Biomechanical and functional behavior of implants.

The ability to achieve a long-term stable implant interface is not a significant clinical issue when sufficient uni- or bi-cortical stabilization is available. Clinical outcomes studies suggest that the higher-risk implants are those placed in compromised cortical bone (thin, porous, etc.) in anatomic sites with minimal existing trabecular bone (characterized as type IV bone). In establishing and maintaining an implant interface in such an environment, one needs to consider the impact of masticatory forces. These forces, in turn, have the potential to create localized changes in interfacial stiffness through the viscoelastic properties of bone. Changes in these properties will alter the communication between osteocytes and osteoblasts, leading to an increase in new bone growth, a maintenance of established bone, or a loss (potentially catastrophic) of either cortical or trabecular bone. Therefore, a key to understanding the biomechanical and functional behavior at an implant interface is to control the extent of anticipated modeling and remodeling behavior through an optimal implant design combined with a thorough understanding of how tissues respond to the mechanically active environment.