Which of the Following Is the Main Difference Between a Manually

Multiple Choice

Which of the following is the main difference between a manually tuned and an autotuned ultrasonic instrument or unit?

A) The manually tuned instrument has less "clinical power" than the autotuned instrument.
B) The autotuned unit has a preset frequency, and the manually tuned unit does not.
C) The manually tuned unit does not require water as a coolant, but the autotuned unit does.
D) Amplitude is greater with the autotuned unit than with the manually tuned unit.
E) Autotuned units have inserts and manually tuned have tips to contact the tooth.