การปรับปรุงเครื่องขูดหินปูนแบบอัลตร้าโซนิคสาหรับชุดทันตกรรมเคลื่อนที่

This research presents the development of ultrasonic scaler for mobile dental unit. The operation of the scaler uses a phase-locked loop circuit to generate high frequency electrical signal. Then the signal is amplified with a Darlington amplifier circuit to feed to the coil in the Hand Piece resulting in Magnetostriction. This phenomenon causes the stretching and shrinking of the magneto-strictive stack with high frequency which causes the tip of the scaling head to vibrate more than 20000 times/second. Traditional ultrasonic scaler for mobile dental unit has thermal problem of the amplifier circuit due to use of the transistors as the switching devices. When used for a period of time the scaler is necessary to stop working resulting in not much scaling per day. This research solved the problem by using MOSFETs as switching devices and adding cooling system to the amplifier circuit. The experiment was carried out using actual conditions. The experimental results show that the developed scaler has increased the number of scaling per day. In addition it will still remove plaque and dirt in the gumline around the base of the teeth similar to the scaler used by general dentists.