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Ultrasonic assessment of the in vitro biomechanical stability of a dental implant

Dental implants are widely used for oral rehabilitation. However, there remain risks of failure which are difficult to anticipate. The objective is to investigate the potentiality of a quantitative ultrasound method to assess the biomechanical stability of a dental implant in vitro. Two experimental configurations were considered using a 10 MHz contact transducer located at the implant extremity. For each ultrasound measurement, a quantitative indicator I is derived based on the time variation of the amplitude of the rf signal. Firstly, seven implants were embedded in tricalcium silicate-based cement. One implant was left without any mechanical solicitation and six implants were subjected to mechanical stresses during 24 hours. The ultrasonic response of each implant was measured during 24 hours. The results show no variation of I without mechanical solicitation, while I significantly increases as a function of fatigue time. Secondly, ten implants were unscrewed from bone tissue and their ultrasonic respo...