Design/exploration and verification of an electromagnetic probe for assessing dental implant osseointegration

Osseointegration is the key to the success of surgery of dental implantation. In this study, we proposed, implemented and explored a handheld and noncontact electromagnetic-type stability assessment device for the use after surgery. The device with two pairs of dual inductors incorporating with a driving signal of swept wavelets was first proposed. This detection device feeds 200–10 kHz of alternating current into an inductor to produce swept broadband magnetic flux and excite the implant structure with a magnetic pole. The implant vibration causes magnetic-flux changes and generates an induced electromotive force. The implant structure resonance frequency (RF) can be characterized to exhibit osseointegration status by evaluating the frequency response function. In vitro bone block experiment and in vivo animal testing were performed to validate the developed device. For bone block experiment on fourteen designs, besides two cancellous bones and two cortical-shell thicknesses, four interface tissues produced using varied mixing ratios of epoxy adhesive were to imitate osseointegration progress. Further, a pilot animal test was conducted on five female New Zealand rabbits to assess implant osseointegration in live bodies. Statistical analyses for varied bone models on measured RF, and the regression analysis between the measured RF and Osstell^TM ISQ for in vivo testing were performed. The correlation analysis on the built regression models shows a close relationship between the measured RFs and ISQ quotients with the determination coefficients up to over 0.9.