Ultrasonic toothbrush

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Ultrasonic toothbrush (Megasonex) Megasonex.jpg
Ultrasonic toothbrush (Megasonex)

An ultrasonic toothbrush is an electric toothbrush designed for daily home use that operates by generating ultrasound in order to aid in removing plaque and rendering plaque bacteria harmless. It typically operates on a frequency of 1.6 MHz, which translates to 96,000,000 pulses or 192,000,000 movements per minute. Ultrasound is defined as a series of acoustic pressure waves generated at a frequency beyond human hearing. [1]



Electric toothbrushes have been used by the public since the early 1950s. Today, they have evolved and based on the speed of their vibration, can be divided into three categories: electric, sonic and ultrasonic.

Electric toothbrushes vibrate in either an up/down direction, or in a circular motion, and sometimes in a combination of the two. Typically, the speed of their vibration is measured in movements per minute, where common electric toothbrushes vibrate at a speed of between a few thousand times a minute to approximately 10,000 to 12,000 times per minute. Sonic toothbrushes are called sonic because the speed or frequency of their vibration, as opposed to the sound of the motor, falls within the average range that is used by people in communication. The voiced speech of a typical adult male will have a fundamental frequency from 85 to 180 Hz (10,200 to 21,000 movements per minute), and that of a typical adult female from 165 to 255 Hz (19,800 to 30,600 movements per minute). [2] [3] Ultrasonic toothbrushes work by generating an ultrasonic wave usually from an implanted piezo crystal, the frequency of which is in the range of 20,000 Hz (2,400,000 movements per minute). The most common frequency however, around which many scientific studies have been conducted, [4] is in the area of approximately 1.6 MHz, which translates to 96,000,000 waves or 192,000,000 movements per minute.


The first ultrasonic toothbrush, initially branded Ultima and later Ultrasonex by Sonex Corporation, was first patented in the USA in 1992 by Robert T. Bock, [5] the same year the FDA gave it approval for daily home use. Initially, the Ultima worked only on ultrasound. A few years later, a motor was added to the Ultrasonex brush, which provided additional sonic vibration. Sonex was then sold to Salton, Inc., who began distributing the product in many countries, including the USA. In 2008, Salton Corporation's new owners decide to exit the oral hygiene market and since then, several new companies started selling ultrasonic toothbrushes such as the Ultreo, Megasonex, and Emmi-Dent brands. In addition, in late 2012, Robert T. Bock created a new Ultrasonic toothbrush, the Smilex Ultrasonic Toothbrush using updated technology. Today, most ultrasonic toothbrushes simultaneously work in the ultrasonic mode together with sonic vibration. As of November 2018, the only Ultrasonic toothbrushes being marketed are the brands Emmi-Dent, Megasonex and Smilex.[ citation needed ]


Ultrasound, in the range of 1.0 to 3.0 MHz[ citation needed ] is used in some therapeutic medical devices to: increase the speed of bone healing; [6] treating aphthous stomatitis, [7] treating gingival bleeding; [8] and plaque removal. [9]

Safety of ultrasound

Ultrasound has been used in medicine for close to half a century and its safety has been studied for almost the same period of time. In 1992, the US FDA first allowed the use of ultrasound at a frequency of 1.6 MHz in a toothbrush. In 1993, the American Institute of Ultrasound in Medicine (AIUM), in conjunction with the National Electrical Manufacturers Association (NEMA) developed the Output Display Standard (ODS), including the thermal index and mechanical index which have been incorporated into the FDA's new regulations. These regulations limit the power output of these devices to a level low enough to avoid raising surrounding tissue temperature by more than 1 °C. [10]

Related Research Articles

Hertz SI unit for frequency

The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named after Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (103 Hz, kHz), megahertz (106 Hz, MHz), gigahertz (109 Hz, GHz), terahertz (1012 Hz, THz), petahertz (1015 Hz, PHz), exahertz (1018 Hz, EHz), and zettahertz (1021 Hz, ZHz).

Ultrasound Sound waves with frequencies above the human hearing range

Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.


A toothbrush is an oral hygiene instrument used to clean the teeth, gums, and tongue. It consists of a head of tightly clustered bristles, atop of which toothpaste can be applied, mounted on a handle which facilitates the cleaning of hard-to-reach areas of the mouth. They are usually used alongside floss.

Toothpaste Paste or gel dentifrice used to clean and maintain the health of teeth

Toothpaste is a paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients to help prevent tooth decay and gum disease (gingivitis). Salt and sodium bicarbonate are among materials that can be substituted for commercial toothpaste. Large amounts of swallowed toothpaste can be toxic.

Teeth cleaning is part of oral hygiene and involves the removal of dental plaque from teeth with the intention of preventing cavities, gingivitis, and periodontal disease. People routinely clean their own teeth by brushing and interdental cleaning, and dental hygienists can remove hardened deposits (tartar) not removed by routine cleaning. Those with dentures and natural teeth may supplement their cleaning with a denture cleaner.

Diathermy is electrically induced heat or the use of high-frequency electromagnetic currents as a form of physical therapy and in surgical procedures. The earliest observations on the reactions of high-frequency electromagnetic currents upon the human organism were made by Jacques Arsene d'Arsonval. The field was pioneered in 1907 by German physician Karl Franz Nagelschmidt, who coined the term diathermy from the Greek words dia and θέρμη therma, literally meaning "heating through".

Sonic weapon A weapon that uses soundwaves to discomfort, capacitate or kill opponents.

Sonic and ultrasonic weapons (USW) are weapons of various types that use sound to injure, incapacitate, or kill an opponent. Some sonic weapons are currently in limited use or in research and development by military and police forces. Some of these weapons have been described as sonic bullets, sonic grenades, sonic mines, or sonic cannons. Some make a focused beam of sound or ultrasound; some make an area field of sound.

Sonicare is the brand name of an electric toothbrush produced by Philips.

An electric toothbrush is a toothbrush that makes rapid automatic bristle motions, either back-and-forth oscillation or rotation-oscillation, in order to clean teeth. Motions at sonic speeds or below are made by a motor. In the case of ultrasonic toothbrushes, ultrasonic motions are produced by a piezoelectric crystal. A modern electric toothbrush is usually powered by a rechargeable battery charged through inductive charging when the brush sits in the charging base between uses.

Piezoelectric motor

A piezoelectric motor or piezo motor is a type of electric motor based on the change in shape of a piezoelectric material when an electric field is applied. Piezoelectric motors use the converse piezoelectric effect of piezoelectric sensors, in which deformation or vibration of the piezoelectric material produces an electric charge. An electrical circuit makes acoustic or ultrasonic vibrations in the piezoelectric material, which produce linear or rotary motion. In one mechanism, the elongation in a single plane makes a series of stretches and position holds, analogous to the way a caterpillar moves.

Ultrasonic motor

An ultrasonic motor is a type of electric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation. Ultrasonic motors differ from piezoelectric actuators in several ways, though both typically use some form of piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials. The most obvious difference is the use of resonance to amplify the vibration of the stator in contact with the rotor in ultrasonic motors. Ultrasonic motors also offer arbitrarily large rotation or sliding distances, while piezoelectric actuators are limited by the static strain that may be induced in the piezoelectric element.


Sonication is the act of applying sound energy to agitate particles in a sample, for various purposes such as the extraction of multiple compounds from plants, microalgae and seaweeds. Ultrasonic frequencies (>20 kHz) are usually used, leading to the process also being known as ultrasonication or ultra-sonication.

Laser-ultrasonics uses lasers to generate and detect ultrasonic waves. It is a non-contact technique used to measure materials thickness, detect flaws and carry out materials characterization. The basic components of a laser-ultrasonic system are a generation laser, a detection laser and a detector.

Tooth brushing Manual abrasion of the surfaces of the teeth.

Tooth brushing is the act of scrubbing teeth with a toothbrush, usually equipped with toothpaste. Interdental cleaning can be useful with tooth brushing, and together these two activities are the primary means of cleaning teeth, one of the main aspects of oral hygiene.

Therapeutic ultrasound refers generally to any type of ultrasonic procedure that uses ultrasound for therapeutic benefit. Physiotherapeutic ultrasound was introduced into clinical practice in the 1950s, with lithotripsy introduced in the 1980s. Others are at various stages in transitioning from research to clinical use: HIFU, targeted ultrasound drug delivery, trans-dermal ultrasound drug delivery, ultrasound hemostasis, cancer therapy, and ultrasound assisted thrombolysis It may use focused ultrasound (FUS) or unfocused ultrasound.

Ultrasonic transducer Acoustic sensor

Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound.

Oral hygiene Cleaning the mouth by brushing the teeth and cleaning in between the teeth.

Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems by regular brushing of the teeth and cleaning between the teeth. It is important that oral hygiene be carried out on a regular basis to enable prevention of dental disease and bad breath. The most common types of dental disease are tooth decay and gum diseases, including gingivitis, and periodontitis.

Sonoporation, or cellular sonication, is the use of sound for modifying the permeability of the cell plasma membrane. This technique is usually used in molecular biology and non-viral gene therapy in order to allow uptake of large molecules such as DNA into the cell, in a cell disruption process called transfection or transformation. Sonoporation employs the acoustic cavitation of microbubbles to enhance delivery of these large molecules. The bioactivity of this technique is similar to, and in some cases found superior to, electroporation. Extended exposure to low-frequency (<MHz) ultrasound has been demonstrated to result in complete cellular death (rupturing), thus cellular viability must also be accounted for when employing this technique.

Debridement (dental)

In dentistry, debridement refers to the removal by dental cleaning of accumulations of plaque and calculus (tartar) in order to maintain dental health.

Ultrasonic antifouling is a technology that helps reduce fouling on underwater structures, through using small-scale acoustic cavitation to destroy, denature and discourage attachment of algae and other single-celled organisms.


  1. "High Intensity Focused Ultrasound - Physics". uci.edu. Retrieved 27 January 2015.
  2. Titze, I.R. (1994). Principles of Voice Production, Prentice Hall (currently published by NCVS.org) (pp. 188), ISBN   978-0-13-717893-3.
  3. Baken, R. J. (1987). Clinical Measurement of Speech and Voice. London: Taylor and Francis Ltd. (pp. 177), ISBN   1-5659-3869-0.
  4. Shinada, K; Hashizume, L; Teraoka, K; Kurosaki, N (1999). "Effect of ultrasonic toothbrush on Streptococcus mutans". Japan J. Conserv. Dent. 42 (2): 410–417.
  5. US Patent number US5247716, August 18, 1992, Robert T. Bock
  6. Padilla, F; Puts, R; Vico, L; Raum, K (Jul 2014). "Stimulation of bone repair with ultrasound: a review of the possible mechanic effects". Ultrasonics. 54 (5): 1125–45. doi:10.1016/j.ultras.2014.01.004. PMID   24507669.
  7. Brice, SL (Jan 1997). "Clinical evaluation of the use of low-intensity ultrasound in the treatment of recurrent aphthous stomatitis". Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 83 (1): 14–20. doi:10.1016/s1079-2104(97)90084-6. PMID   9007917.
  8. Terezhalmy, GT; Iffland, H; Jelepis, C; Waskowski, J (Jan 1995). "Clinical evaluation of the effect of an ultrasonic toothbrush on plaque, gingivitis, and gingival bleeding: a six-month study". J Prosthet Dent. 73 (1): 97–103. doi:10.1016/s0022-3913(05)80278-1. PMID   7699607.
  9. Shinada, K; Hashizume, L; Teraoka, K; Kurosaki, N (1999). "Effect of ultrasonic toothbrush on Streptococcus mutans". Japan J. Conserv. Dent. 42 (2): 410–417.
  10. American Institute of Ultrasound in Medicine (AIUM). Bioeffects and safety of diagnostic ultrasound. Laurel, MD: AIUM Publications; 1993

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