An ultrasonic cleaner is a pre-sterilization device used in dental clinics to thoroughly clean instruments before they are placed in an autoclave. It works by generating high-frequency sound waves that create microscopic bubbles in a cleaning solution, a process called cavitation. These bubbles collapse rapidly and gently remove blood, tissue, plaque, and other debris from small crevices and hard-to-reach areas of dental instruments. This process improves the effectiveness of sterilization and extends the life of the instruments.