How UVC lights work
I started off by doing a little research to see if UV lights were proven to be effective or if this was just hype. I discovered that the type of UV radiation used in these devices is called ultraviolet-C (UVC) and has been used for decades to decrease the spread of bacteria as explained by the US Food and Drug Administration. This special type of light can be used on air, water, and nonporous surfaces.1 The disinfection of water is currently the most widely accepted application for UVC light.2
As far as ultraviolet light is concerned, there are three different types: ultraviolet-A, -B, and -C.3 Ultraviolet-A is the most common type that we are exposed to from the sun, accounting for 95% of the ultraviolet radiation landing on the earth’s surface. It has the longest wavelength. Ultraviolet-B has a medium wavelength and is the damaging light that is responsible for sunburns, skin cancer, and aging. Ultraviolet-C, with the highest frequency, is the most damaging type of UV radiation. UVC does not naturally reach ground level as it is filtered out by the earth’s atmosphere.
The wavelength of UV radiation is strictly defined in the range of 210–328 nanometers (nm).4 Its maximum bactericidal effect occurs from 240–280 nm. This type of light is effective against microorganisms, because it causes the creation of thymine dimers, or double bonds. Thymine is one of the basic components of DNA. Permanent cellular damage occurs when this change to thymine occurs and further replication is inhibited.5 It is also important to consider that UVC light is not proven to destroy COVID-19, although it has been shown to be effective against other coronaviruses, but only when a specific wavelength of light is used.6
Trying out a UVC light for myself
I decided to try out a UV disinfecting wand as it was the most readily available option for me. Whole-room disinfecting lights have drawbacks in that they must be utilized only when the room is completely empty; as such they are often equipped with motion sensors.5 Smaller countertop units are limited by the size of items they are able to disinfect. UVC wands, however, are relatively inexpensive and have the advantage of being easily movable from room to room.
The wand I tried out is manufactured by Dine Corp. The company claims that the disinfecting wand is designed to kill up to 99.9% of bacteria and viruses.7 There are two different models available. The first is 12 inches by 1.5 inches. It is rechargeable and provides three hours of continuous usage. It is recommended that the light from this wand be used three-to-four inches away from the desired surface for a minimum of 10 seconds per inch. The light wavelength emitted is 264 nm, which is in the correct range for disinfecting bacteria and viruses on surfaces.
The second wand model is a foldable UVC disinfection wand that is small enough to fit in a pocket. When disinfecting a surface, this wand is held two to three inches above the area it is scanning in two-inch sections for 20–30 seconds. The wavelength of light emitted ranges from 265–280 nm. After being charged by a USB cable, the foldable wand can be used for up to 120 minutes.
One caution about this product is that it absolutely cannot be shined directly into anyone’s eyes. It is also not to be used on human skin under any circumstances. As mentioned above, this type of UV light can be highly damaging. Although it may be tempting to use it directly on skin, it can cause burns within a matter of seconds.6 The foldable wand made by Dine Corp has a safety feature that automatically turns off the unit if it is facing upward.7 UVC safety goggles can also be purchased.
I have found that the foldable wand is convenient, lightweight, and easy to use in the dental operatory. It is reassuring to be able to further disinfect the electronics I use on a regular basis with a no-touch system. I often utilize tape and plastic barriers to cover my keyboard and mouse, but I’ve never been sure whether this action is effective enough. The UV wand has definitely made my operatory feel like a safer place with its comforting purple light hard at work.
After getting good results from using this product in the operatory, I also started using the foldable wand on some of my personal items that can be difficult to keep clean—e.g., my car keys, cash, and cell phone. It has reassured me to know that these frequently touched and difficult-to-disinfect items are cleaner as I carry them around. I even took a wand on my trip to visit family in Florida this summer, and my children and I came back as healthy as ever.
If there is anything we have learned in dentistry since COVID-19, it is that we must be hypervigilant about infection control. Keeping our eyes open for various ways to accomplish this objective is the best way to keep our patients and ourselves safe. New disinfection measures, such as use of a UVC sanitizing light, can help us pave the path for a safer practice of dentistry for years to come.
