Key Technologies Of Ultrasonic Vibration Assisted Dendal High-speed Grinding

Oral cavity high-speed grinding is the most widely used technique in oral repair surgery.However,patients feel uncomfortable because the large grinding force during the surgery.For this problem,this paper presented axial ultrasonic vibration assisted oral high-speed grinding.With the support of the national natural science foundation,the mechanisms of the axial ultrasonic vibration to the oral cavity were studied.The main contents include:The grinding forces in dental grinding of ceramics using a dental handpiece with and without axial ultrasonic vibration were investigated.The relationship of the grinding force and process parameters in up and down grinding process,and the effect of axial ultrasonic vibration in grinding process were approached.The beneficial effects of axial ultrasonic vibration for grinding four different dental materials were obtained with obviously reduced normal force and tangential force regardless of different dental burs and process parameters.The surface roughness and three-dimensional morphology of the restorer were studied.The results show that the roughness of Sq and Sz value do not influenced by the cutting depth obviously,but will increase with increase of the feed rate and decrease of the rotational speed.When the parameter of cutting depth is small,ultrasonic vibration can effectively reduce the roughness value of Sq and Sz of Enamic,Mark Ⅱ,Suprinity and Lava Ultimate.With the axial ultrasonic vibration,brittle fracture zone of the above materials can be reduced effectively,and the fracture morphology of brittle fracture is refined,the longitudinal crack is inhibited.The study results of the wear of the bur show that the ultrasonic vibration can effectively improve the wear phenomenon in spite of different processing parameters and materials.A new axial ultrasonic vibration assisted rotating dental handpiece was presented.The amplitude amplification ratio and the structure size of the amplitude transformer were designed.Furthermore,the modal analysis and size optimization of ultrasonic vibrator were carried.