There are many brush types of cleansing implements currently marketed to enhance cleansing of the face. Many of these brush designs have evolved from toothbrushes to face brushes. The most popular type of face brush rotates one direction moving the bristles in a circular motion over the skin. The complaint with this type of cleansing action is that it cleans the skin dermatoglyphics in one direction leaving behind facial dirt and cosmetics. The idea of a sonicating brush developed to more thoroughly clean the skin dermatoglyphics by first moving the bristles to the right and then to the left. A sonicating brush moves the bristles back and forth rapidly such that the human eye cannot observe the oscillations. Only the bristles in the center of the sonicating brush move with a fixed row of bristles present on the periphery. The role of the fixed bristles is to prevent from getting tangled and pulled in the oscillating brush head and also to hold the skin in place as the moving bristles tug it forward and backward.
Some controversy has arisen regarding the degree to which the sonicating motion moves the skin. If the head is not properly powered, it will simply vibrate the skin with the movement and not push and pull the skin to achieve cleansing and exfoliation. This may explain why some sonicating cleansing brushes work better than others. One advantage of sonicating brushes is that they foam the soap thoroughly, which may produce better cleansing. Actually, the excellent foam action may lead to too much foam, thus many sonicating brushes come with their own cleanser that contains a lower concentration of foaming agents.