figure 3-6. Follow the manufacturer's instructions on setup, adjusting water flow, ultrasonic tuning, and ultrasonic power. Some units are tuned automatically while others require manual tuning.

ELECTRONIC GENERATOR. - The electronic generator produces the power required to activate the handpiece. The three controls located on the front panel of an automatically tuned ultrasonic unit are the ON/OFF indicator, POWER ADJUSTMENT CONTROL, and a WATER ADJUSTMENT CONTROL. A manually tuned ultrasonic unit will also have a TUNING ADJUSTMENT CONTROL.

HANDPIECE AND CABLE ASSEMBLY. - This assembly consists of a handpiece into which interchangeable scaling inserts are placed. A cable connects the handpiece to the generator. To place an

Figure 3-7. - Placement of the insert into the handpiece.

insert into the handpiece, first lubricate the O-ring with water. Then hold the handpiece with the open end upright over a sink or suitable basin. Step on the foot switch to turn on the unit and flood the handpiece chamber with water. Stop flooding when you see the water has reached a level halfway up the handpiece. Push the insert into the open end of the handpiece with a twisting motion (fig. 3-7); a small amount of water may be displaced by the insert stack and may spill out. Check to see if the insert is fully seated. With the insert in place, hold the handpiece in an upright position. Activate the insert and bleed off any air trapped during handpiece insertion. Allow the water to run from the handpiece for a few seconds until it flows without spurting. Repeat this procedure each time an insert is placed into the handpiece. Trapped air does not interfere with the handpiece operation, but can cause excessive heating of the instrument.

INTERCHANGEABLE INSERTS. - A set of interchangeable inserts facilitates access to all areas of the mouth. The components of an insert include the insert tip, water outlet, plastic grip, O-ring, connecting body, and the magnetostrictive stack (fig. 3-8). The water outlet delivers preheated water along the entire working length of the tip. The O-ring acts as a water seal when the insert is placed into the open end of the handpiece. A connecting body transmits motion from the stack to insert tip. The magnetostrictive stack converts electrical power supplied to the handpiece into mechanical vibrations to activate the insert tip.

FOOT CONTROLLED SWITCH. - The handpiece is activated by a foot-operated on/off switch. When the foot pedal is held down, the handpiece is activated and water flows. Both the handpiece and water flow are shut off when the pedal is released.

Water Supply

Attached to the ultrasonic scaling unit is a water supply hose. The free end of the hose attaches to a

Figure 3-8. - Components of the interchangeable inserts.