Electric toothbrush
[5] The General Electric automatic toothbrush was introduced in the early 1960s;[6] it was cordless, with rechargeable NiCad batteries and although portable, was rather bulky, about the size of a two-D-cell flashlight handle.
The GE automatic toothbrush came with a charging stand that held the hand piece upright; most units were kept in the charger, which is not the best way to get maximum service life from a NiCad battery.
By the early 1990s Underwriter Laboratories (UL) and Canadian Standards Association (CSA) no longer certified line-voltage appliances for bathroom use.
[citation needed] The first ultrasonic toothbrush, first called the Ultima and later the Ultrasonex, was patented in the US in 1992, the same year the FDA gave it approval for daily home use.
Initially, the Ultima worked only on ultrasound, but a few years later, a motor was added to give the Ultrasonex brush additional sonic vibration.
Some versions of the oscillating rotating toothbrush also involve a pulsating motion which enables a more three dimensional clean.
Most modern rechargeable electric toothbrushes from brands such as Sonicare, FOREO, and Oral-B fall into this category and typically have frequencies that range from 200 to 400 Hz, that is 12,000–24,000 oscillations or 24,000–48,000 movements per minute.
In order for a toothbrush to be considered "ultrasonic" it has to emit a wave at a minimum frequency of 20,000 Hz or 2.4 million movements per minute.
Typically, ultrasonic toothbrushes approved by the U.S. Food and Drug Administration (FDA) operate at a frequency of 1.6 MHz, which translates to 192 million movements per minute.
These vibrations break up bacterial chains that make up dental plaque and remove their methods of attachment to the tooth surface up to 5 mm below the gum line.
Other ultrasonic toothbrushes, such as the Ultreo and the Megasonex, provide additional sonic vibration ranging from 9,000 to 40,000 movements per minute, comparable to a sonic toothbrush, in order to provide additional sweeping motion which facilitates removal of food particles and bacterial chain remnants.
[10] Although the scale of these differences in a clinical setting remains questionable,[10] other reviews have reached similar conclusions.
[23][24] Another large review of studies also concluded that power toothbrushes were more effective in removing plaque than manual brushes for children.
[25] For patients with limited manual dexterity or where difficulty exists in reaching rear teeth, electric toothbrushes may be especially beneficial.
A few units use a step-down transformer to power the brush, but most use a battery, usually but not always rechargeable and non-replaceable, fitted inside the handle, which is hermetically sealed to prevent water damage.
According to Friends of the Earth, "Disposable electric toothbrushes are one example of a terrible product ... it's virtually impossible to separate out the tech from the batteries and plastic casing which means valuable and often toxic materials are dumped in landfill or burnt in incinerators.
[9] Many modern electric toothbrushes have a timer that buzzes, or briefly interrupts power, typically after two minutes, and sometimes every 30 seconds.
Most modern top-end sonic toothbrushes come with a pressure sensor, which prevents users from brushing too aggressively.
Some sensors produce a sound warning and some immediately stop movements of the sonic toothbrush when it is used too aggressively.
The sharing of data between toothbrush and smartphone is intended to assist the user in creating better brushing technique and habits.
Since ultrasound movements are very low in amplitude, this setting may be indicated for patients who may not be suitable candidates for typical sonic or power toothbrush vibration but need the additional cleaning power of an ultrasonic toothbrush, such as patients who have recently undergone periodontal surgery.
