Just that. I'm looking for a new electric toothbrush and keep seeing 'sonic'. With various numbers attached. I presume that's related to how fast they oscillate. They range from £45-500 so, y'know, for hundreds of pounds I'll be expecting all singing, all dancing dental equipment.
I was happy with my electric toothbrush, till it gave up, and my teeth always felt clean enough. These sonic ones say they're better for breaking down plaque (but then they've got to sell themselves, haven't they?)
I keep thinking of the sonic showers in Star Trek, where no water was involved. I think the sonic waves just broke down the dirt and left you clean. Presumably that's not how they work? 😋