Dental Assistant Practice Exam

What mechanism does an ultrasonic cleaner use to remove debris from instruments?

1. High-pressure steam

2. Cold water and rinsing

3. Sound waves, water, and detergent

4. Chemical disinfectants

The correct answer is: Sound waves, water, and detergent

An ultrasonic cleaner operates by utilizing high-frequency sound waves, typically in the range of 20-400 kHz, which create millions of tiny bubbles in a liquid solution composed of water and a detergent. This process is known as cavitation. As the ultrasonic waves travel through the solution, they cause these bubbles to rapidly form and collapse. When the bubbles implode, they generate tiny shock waves that effectively dislodge particles, debris, and contaminants from the surfaces of the instruments being cleaned. This method is particularly effective for cleaning intricate and delicate instruments, as it ensures that even the smallest crevices are cleaned without causing any damage to the instruments. The detergent in the solution enhances cleaning by breaking down the organic and inorganic materials on the instruments, allowing for more effective removal during the cavitation process. Other mentioned mechanisms like high-pressure steam or chemical disinfectants serve different purposes in cleaning and sterilization, but they do not utilize the specific technology of sound waves creating cavitation to achieve thorough cleaning of instruments like an ultrasonic cleaner does.