Non-contact Vibro-acoustic Detection Technique for Dental Osseointegration Examination

This study develops a non-contact vibro-acoustic detection technique for measuring the defect quantity and determining the imperfection orientation surrounding a bone-implant interface. Acoustic excitation through a miniature loud speaker and vibration response measurement using a capacity-type displacement sensor are applied to accomplish this task to prevent the mass loading effect on the structure to be examined. The proposed non-contact excitation-response measurements are verified using a series of designated in vitro defect models, and the measured resonance frequencies (RFs) are used to discriminate interfacial structure variations. A finite element modal analysis is conducted to validate the measured RFs. Additionally, a prototype device is developed and applied to assess the osseointegration between dental implants and tibia in an in vivo animal model. A comparison of in vitro experimental results with numerical simulations shows that the RFs in the defective orientation are significantly smaller than those in the complete direction (p < 0.05), and that the values decrease with increasing defect quantity (p < 0.05). Moreover, the defect depth affects RF variation. In the in vivo experiments, the RF levels in the lateral direction of the tibia are much higher than those in the axial direction (p < 0.05) of the tibia. The RF values in the axial direction for two implants have no significant difference (p = 0.552), but the RFs in the lateral direction for implant 2 are higher than those for implant 1 (p < 0.05). The RF changes can be compared to assess osseointegration development. The proposed technique is promising for assisting dentists in the assessment of implant stability after surgery.