A review of nondestructive test methods and their application to measure the stability and osseointegration of bone anchored endosseous implants.

Threaded and cylindrical metallic endosseous implants are being used increasingly in cranio-facial, dental, and orthopedic surgery. There is a significant need for the development of quantitative noninvasive test methods to measure implant stability and success. Such success can be quantified by measurements of the stiffness and damping of an implant in the surrounding bone, and also the height of the marginal bone around an implant. In the case of a failing implant, the bone around it is replaced by fibrous tissue, and in the case of an overloaded implant the bone height around the implant falls. Nondestructive test methods have been applied to the testing of implant and tooth mobility, and commonly these have used transient or steady-state test methods. Transient methods entail tapping an implant, measuring its response and then performing a Fast Fourier Transform to resolve the fundamental frequencies. Steady-state methods measure the frequency response of a system using a swept frequency wave form. A number of dedicated electronic instruments have been designed to perform these tasks, and this article discusses their applications, accuracy, and value as clinical diagnostic instruments.