Power Brushes…From Novelty to Necessity

According to the Lemelson-MIT Invention Index, the toothbrush was selected in 2003 as the No. 1 invention Americans could not live without, beating out the automobile, personal computer, cell phone, and microwave^.1
Historians believe the traditional handheld toothbrush originated in China in the 1600s. Through the centuries, other choices for personal oral care have included toothpicks, chew sticks, tree twigs, strips of linen, bird feathers, animal bones, and porcupine quills2 (Figure 1).
Traditional handheld toothbrushes, popularized during the Victorian era, were first mass-produced in the United States in 1885. The first commercially fabricated brushes were made with boar bristles. Nylon bristle brushes came on the market in 1938. The practice of daily brushing, which was a part of the American soldier’s daily duty, became commonplace in the United States after World War II.²
The first electric brush, called the Broxodent, was developed in Switzerland in 1939. The power tooth-brushing industry began in this country when Squibb Pharmaceuticals introduced Broxodent to the US market during the 1959 American Dental Association Centennial Meeting.³ This early power brush was a plug-in device that featured bristles that moved from side to side. It was quite basic as compared to today’s models, which incorporate complex technologies in user-friendly formats.

Figure 1. A bundle of chew sticks from Nigeria. Loose twigs, known as miswaaks, from Dubai.

In 1683, well-known Dutch scientist Antony van Leeuwenhoek wrote the Royal Society of London about his examination of the scrapings from his own teeth made under the lens of an early microscope. He observed tiny moving organisms floating and spinning through the soft mass. This centuries-old discovery seems primitive by today’s standards, but this early description of plaque biofilm was the basis for modern-day microbiology.⁴

BIOFILM—DISEASE INITIATION AND REMOVAL WITH NONPOWERED DEVICES

Countless publications support the role of plaque biofilm in the development of both caries and periodontal disease.^5-7 Plaque biofilm is a sticky substance that can be quite difficult to remove.^8,9 For many years, both clinicians and patients employed nonmechanical devices to disrupt biofilm. De-spite the proliferation of hand instrument designs and manual brush configurations, the overall success of either strategy was limited. Biofilm disruption with a manual brush can be tedious, time consuming, and lack effectiveness. Many studies demonstrate that today’s power brushes provide more thorough disruption and subsequent removal of plaque biofilm than the results obtained via the use of a manual brush.^8-10
The initial attraction to power brushes has many reasons. Some users are interested in technology and the potential for easier, more thorough plaque removal. Others, who have either diminished manual dexterity or limited mouth opening, find power brushes streamline their ability to maintain good oral health. In addition, power brushes simplify plaque removal around orthodontic appliances, fixed prosthetic devices, malpositioned teeth, and bony protuberances. Caregivers, with proper instruction, can achieve better oral hygiene outcomes for those under their care.
Hand scaling faces similar limitations to that of working with a hand brush. The final results can be complicated by complex tooth anatomy, challenging tooth alignment, size and sharpness of the scaling instrument, limited accessibility, clinician skills, and instrumentation time.

EFFECT OF ULTRASONIC SCALERS AND POWER BRUSHES ON PLAQUE BIOFILM

From a historical standpoint, the first power scalers appeared at the same time as the first electric toothbrush.^3,11 In recent years, the use of both power brushes and power-driven scalers has become more widespread. Clinicians have observed improved oral health outcomes with more frequent use of ultrasonic scaling devices.
A current review of different ultrasonic scaling technologies demonstrates that both piezoelectric and magnetostrictive ultrasonic technologies have the capacity to disrupt plaque biofilm.^12,13 Results reflect clinician skill level, instrumentation time, ultrasonic tip design, and the sophistication of the scaling unit.^11,14 These same factors can affect the outcome of power brush-assisted home care. In addition, lifestyle, immune system status, and frequency of professional visits play a role in preventing or stopping the disease process.
Today’s marketplace is crowded with dozens of power brushes. The choices range from inexpensive, disposable battery-operated rotating brushes to sophisticated rechargeable power brushes that combine mechanical debridement with either sonic action or a combination of sonic and ultrasound activity.^15,16
While power brushes that feature rotational or oscillating brush heads can remove biofilm, their relative effectiveness is limited to areas that receive direct mechanical bristle contact.17-20 Power brushes that utilize direct mechanical scrubbing in combination with fluid dynamics generated via sonic or sonic/ultrasound combinations have demonstrated superiority in biofilm removal, especially beyond the bristle tips.^18-24

ROLE OF SONIC POWER BRUSHES IN BIOFILM DISRUPTION

Figure 2. Sonicare Elite power brush with max and gentle power settings.

The Sonicare brush, first introduced by Optiva 15 years ago, was the first powered brush to incorporate sonic technology, which is sound wave energy that operates at a frequency within the audible range of the human ear. This design breakthrough utilized vibrations created by rare earth magnets to generate unique sonic movements in the brush head bristles. The resulting fluid dynamics created turbulent forces to assist in removing biofilm from tooth surfaces.^18-22 Numerous research studies demonstrate the effectiveness of this type of power brush design.
The entry of the Sonicare brush was analogous to clinicians embracing power scaling as a means of providing more effective biofilm removal. From a clinical standpoint, it quickly became clear that sonic brushes, if used effectively, could be a key player in disease prevention by extending the effectiveness of professional care for a longer period. Patients and clinicians soon learned to expect improved health outcomes when both power scalers and power brushes were used to disrupt plaque biofilm.
Over time, newer Sonicare models (Philips) emerged that featured smaller brush heads, angled necks, slimmer and more lightweight handles, and more compact, efficient charging systems. The introduction of audible timers provided patients with a more effective means of determining how long they were brushing.
Initially, the Sonicare brush was only dispensed professionally through dental offices, but market distribution soon included a variety of retail establishments, making the brush more readily available to the general public. This strategic change gave consumers the opportunity to purchase their choice of high-end sonic brushes directly. Several years ago, Philips acquired Optiva, the original makers of Sonicare, and the company continues to focus on product innovations (Figure 2).

COMBINING SONIC ENERGY AND ULTRASOUND IN POWER BRUSHING

Figure 3. Ultreo brush combines ultrasound waveguide technology with precisely tuned sonic bristle activity.	Figure 4. Ultreo brush bristles surrounding ultrasound waveguide.

Figure 5. Snap-on Ultreo brush head with multilevel bristles.

Every type of technology has inventors and scientists who dream of creating a new device or combining existing ideas that will result in a product with unique properties. Twenty years ago it would have seemed improbable that ultrasound technology, similar to that utilized in ultrasonic scalers, could be incorporated into power brushes. Over the past 4 years, scientists have explored ways to merge sonic and ultrasound energy into a power brush system.²⁵ The new Ultreo brush (Ultreo) is the innovative result of these extensive efforts.
The Ultreo features a small, silicone-covered piezo-electric transducer embedded in the center of an oval-shaped brush head. Precisely tuned sonic energy vibrates the bristles surrounding the transducer to create the desired bubble population. Within this population of bubbles are many bubbles with diameters smaller than the diameter of a toothbrush bristle filament. By virtue of their size, these bubbles may reach areas within the complex oral geometry that bristles cannot. Scientists worked to activate these smaller bubbles using ultrasound energy.
The piezoelectric transducer within the Ultreo brush head generates ultrasound waves, which are transmitted through an ultrasound waveguide toward the tips of the bristles. Bubbles exposed to ultrasound of the proper frequency are known to pulsate in response to an ultrasound wave.²⁶ In vitro research has shown that the combination of sonic and ultrasound processes leads to a synergistic removal of biofilm.²⁵ A clinical study has shown that use of Ultreo can lead to significantly improved oral health²⁷ (Figures 3 to 5).
Two phenomena appear in the technology world. Some companies focus on creating a line extension for an existing product. This type of strategy employs changing the outward appearance of a product or adding a few minor features without making significant changes to the core design of a product. Other companies, typically populated with scientists and engineers, are constantly looking for ways to ramp up their technologies or even create new, novel designs. The continuous improvements in power brush technologies are a perfect example. Companies that are focused on moving forward with science and technology are charting new territories in oral healthcare devices.

INCORPORATING POWER BRUSH TECHNOLOGY

Despite the widespread availability of power brushes, as well as the remarkable improvements in technology, estimates indicate that only about one in 5 people take advantage of the benefits derived from improved biofilm disruption via power brushes.
We can learn something from the telecommunications industry. Cell phones were initially considered luxury devices, reserved for the wealthy gadget guru. Pay phones are nearly extinct and landline use is down. Everyone from 10-year-olds to great grandmas have cell phones. Mobile communication devices are now a daily necessity.
If the toothbrush is truly the No. 1 invention that Americans feel they cannot live without, why doesn’t everyone have a power brush in one hand and a cell phone in the other? How can we create the same sense of necessity? Now is the time to take lessons learned from other technology sectors and help our patients move forward with improved oral health.

References

Ms. Guignon is an internationally recognized speaker and author, and has authored textbook chapters on ergonomics and power-driven scaling. She has more than 150 publications in numerous dental periodicals covering diverse topics such as ergonomics, ultrasonics, new products, and patient comfort issues. She received her BS in dental hygiene in 1971 from the University of Missouri-Kansas City School of Dentistry and a master’s in public health from the University of Texas in 1988. She has practiced dental hygiene continuously in Houston since 1971 and is an active ADHA member. She can be reached at anne@anneguignon.com.

Disclosure: Ms. Guignon received an honorarium from Ultreo, Inc., for preparation of this manuscript.