Load Transfer Along the Bone-Implant Interface and Its Effects on Bone Maintenance

Abstract

The long term success of dental implant treatment relies on the proper stability of the implant within the host bone. This condition is achieved through osseointegration, which is characterized as a direct functional and structural connection between ingrown bone tissue and implant surface (Branemark et al., 1977; Simmons et al., 2001). Osseointegration begins with rapid growth of random and unorganized woven bone around the implant, while a biomechanically favorable environment at the bone-implant interface develops (Leucht et al., 2007; Schenk & Buser, 1998). This initial bony structure is maintained by bone remodeling and bone adaptation, where woven bone is slowly replaced by more organized lamellar bone. Adaptation of bone morphology in response to functional loads continues throughout life (Schenk & Buser, 1998). The load transfer from the implant to the host bone depends on the amount of bone surrounding the implant and in turn affects the success of treatment, by the load transfer from the implant to the host bone. X-ray imaging, computerized tomography (CT), and histomorphometric evaluation of the extracted implants provide insightful information about the quality and quantity of peri-implant bone. However, systematic evaluation of the mechanism of load transfer and its effect on peri-implant bone remodeling is difficult via aforementioned techniques, due to the cost and effort involved and due to the associated ethical concerns. Reliable computational models can be useful to predict the long term outcome of a dental implant treatment, and thus help with the decisions related to implant treatments and design. In this paper, a state of the art review of the computational models used in evaluating the biomechanics of dental implant systems is provided. The literature shows that load transfer along the bone-implant interface is not well understood, despite the fact that the bone loading starts along this interface. Recently a systematic investigation of the effects of various parameters related to a dental implant’s contour including the implant’s diameter, body-length, collar length and slope, and the morphology of the external threads was carried out by Faegh and Muftu (2010). The variation of normal and shear stresses along the bone dental-implant interface was investigated. Here, in order to generalize the bone morphology an elliptical contour is used. The results are compared to a similar recent study in which the bone contour was drawn from a CT image of the incisor region (Faegh & Muftu, 2010).