One of most critical aspects in the replacement of missing teeth using dental implants is the ability of small screws within the implant complex to hold the various implant parts together during loading and stress transfer. As an implant screw is tightened, the initial stress level developed within the screw becomes critical to the maintenance of the joint stability between the parts the screw is clamping together. Owing to the high strain level that the assembled joint experiences in everyday life, this initial stress level called the preload is of paramount importance. Insufficient tightening of the screw can result in the screw becoming loose rather quickly, and over time this looseness can lead to fracture of the screw and potentially failure of the implant reconstruction. Ultrasound instrumentation has been suggested as an innovative use of acoustic technology to measure the preload established in these implant screws following tightening. The purpose of this research project is to develop an implant screw Preload Measurement Gage (PMG) using ultrasonic techniques.
