a subset of electric toothbrushes with movement that is fast enough to produce vibration in the audible range
Это интересно
Hambaharja pea teeb 24 000 – 48 000 liigutust minutis või 12 000 – 24 000 edasi-tagasiliigutust. Osa mudeleid teevad lausa 62 000 liigutust minutis. Liigutused ja vibratsioon tekitavad kõrvale kuuldava ümiseva heli. Vibreeriv otsik tekitab harjasele justkui suurema amplituudiga liikuva pinna, pühkides mehaaniliselt hammastelt katu ja toidujäägid.
Enamik müügil olevaid elektrilisi hambaharju on helihambaharjad (sonic toothbrushes) ... Helihambaharjad eemaldavad käsiharjaga võrreldes hambakattu väga põhjalikult ja masseerivad igemeid neid traumeerimata.
Sonic toothbrushes have vibrating brush heads that move bristles side-to-side at high speeds. To be classified as a sonic toothbrush, the vibration has to be fast enough to produce an audible hum. Sonic toothbrushes on the market today offer frequencies of up to and over 50,000 movements per minute.
Это интересно
Because of the similarity of the terms "ultrasonic" and "sonic", there is some confusion in the marketplace and sonic toothbrushes are frequently mislabeled as ultrasonic ones. A toothbrush operating at a frequency or vibration of less than 20,000 Hz is a "sonic" toothbrush. It is called "sonic" because its operating frequency, for example 31,000 movements per minute, is within the human hearing range of between roughly 20 Hz to about 20,000 Hz.
