You might not know that it is critical for your dentist to periodically chemically disinfect (purge) their dental unit waterlines. Also, ultrasonic devices, which are typically used for teeth cleaning (prophylaxis), should not be used if the dental office is not regularly disinfecting the ultrasonic device’s waterlines to control bacterial biofilm buildup in the ultrasonic device’s waterline. See Center for Disease Control (CDC) Guidelines for dental office infection control.