Most of us don’t give a second thought to how batteries impact our personal and professional lives. We rely on them to power flashlights, children’s toys, and TV remote controls, as well as countless other devices. For years, AAA, AA, and 9-volt batteries served most consumer needs.
More devices are going cordless. For years, dentistry has been mired in cords everywhere; every device had its own cord, hose, and foot control. Neatniks hated the clutter, and the rest of us resigned ourselves to occasionally taking a flying leap across the room as our feet got tangled in the spaghetti bowl of cords that adorned every treatment room floor for decades.
Portable electronics such as high-end cameras, laptops, and smartphones are possible because of recent advances in battery technology. As portability and wireless technologies transitioned from a dream to reality, dental manufacturers began developing products that could be used with newer rechargeable batteries.
While a more traditional AA or AAA will provide sufficient power for a device like a wireless optical mouse that we use in the treatment room, that type of battery would never work for current portable headlights, cordless polishers, or curing lights. These types of devices need a battery pack that has a high energy density — in other words, enough power to keep a headlight bright throughout the clinical day. Lithium ion batteries provide the appropriate level of power to meet our clinical demands. They are also lightweight, have quick recharge cycles, do not have memory issues, and are more environmentally friendly than the earlier NiMh or NiCad rechargeable batteries.1,2
But like all good things, there is a trade-off. While earlier rechargeable batteries have a much faster discharge rate, lithium ion batteries start degrading as soon as they leave the factory, whether they are put into service or not. At the current level of technology, li-ion batteries will last two to three years at best. And like all rechargeable batteries, there are a finite number of recharge cycles. A typical rechargeable li-ion headlight battery will have 500 recharge cycles. After that point, the charging time increases dramatically and the light output or device function decreases correspondingly.2,3
This means that those of us using today’s portable devices in the clinical setting need to be prepared to either replace the battery packs for these devices every two to three years, or better yet, upgrade to whatever new technology that will be available at that time.
Li-ion batteries are also more expensive — for several reasons. First, there is less consumer demand, which keeps the cost higher. As more devices use li-ion technology, the cost will decrease. Second, li-ion batteries are much more complex to manufacture. If a li-ion battery discharges completely, it is ruined, so these batteries actually include special circuitry to protect the battery from damage due to overcharging or undercharging.
Li-ion batteries are also very heat sensitive. This becomes a problem for those tempted to leave the headlight battery pack in a hot car between clinical sessions at different locations, an issue for students going to off-campus assignments or clinicians who do temporary work or have multiple practice locations.1-3
Despite the initial cost and the few other drawbacks, li-ion technology is here to stay. It makes portability possible, frees us from cords, and makes it possible to work with devices that reduce the strain on our bodies, creating a more ergonomically favorable environment. Portability will also become more critical as dental care is delivered in situations outside of the four walls of a traditional clinical practice.
I’m a recycler at heart, so it pains me to accept that portability means more initial waste, but I am confident that the pluses created by new, emerging technologies will create batteries and recharging options that are beyond our wildest dreams. Technology will insist that we recreate our clinical comfort zones. RDH
References
1. Buchman I. Lithium based batteries. http://batteryuniversity.com/learn/article/lithium_based_batteries. Accessed December 10, 1011.
2. Brain M. How litihium-ion batteries work. http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery.htm. Accessed December 10, 1011.
3. Frequently asked questions about lithium ion (li-ion) batteries. http://www.greenbatteries.com/libafa.html. Accessed December 10, 1011.
Anne Nugent Guignon, RDH, MPH, provides popular programs, including topics on biofilms, power driven scaling, ergonomics, hypersensitivity, and remineralization. Recipient of the 2004 Mentor of the Year Award and the 2009 ADHA Irene Newman Award, Anne has practiced clinical dental hygiene in Houston since 1971.
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