Ultrasonic toothbrushes

Ultrasonic

— the next evolution beyond sonic toothbrushes (see the relevant section) involves an increased operating frequency. It's important to note that formal classifications consider frequencies starting from 20 kHz as ultrasound, which translates to 1.2 million vibrations per minute. However, toothbrushes have their own criteria for categorization, where much lower frequencies are considered ultrasonic—typically starting at 50,000 vibrations per minute (slightly over 800 Hz). Some manufacturers even classify brushes with speeds as low as 40,000 vibrations per minute as ultrasonic. Therefore, the distinction between sonic and ultrasonic models is somewhat subjective and blurry. Nevertheless, in general, these models are more effective than sonic ones. They not only deliver thorough cleaning, reaching into challenging areas, but also possess a bactericidal effect, capable of destroying bacteria that contribute to plaque formation.

The trade-off for this heightened efficiency primarily comes in the form of the relatively higher cost of ultrasonic brushes. Additionally, they are somewhat less effective than sonic brushes at cleaning braces, implants, and similar specialized structures. However, some brushes in this category address this limitation by incorporating two types of vibrations — ultrasonic and conventional sonic — providing a more versatile cleaning approach.