Why Does my Dentist use a Blue Light?
- Sapan Bhatt, DMD
- Jun 22, 2020
- 2 min read
If you've ever had a white filling placed, you'll remember that your dentist used a blue light during the procedure. This is one of the most common questions I get, what is that blue light? Is it giving me ultraviolet (UV) radiation? I'm here to answer those questions.
First off, no, it's is not a UV light. I can understand where the confusion lies because the beam looks like what you'd see from a tanning bed. The light (called a curing light) actually emits visible blue light, much like your phone or TV. And just like your phone or TV, many curing lights are LEDs which allows them to work well over long periods of time without emitting a lot of excess heat, which would be bad for the tooth.
This photo shows a curing light in action. The shape of the light head keeps the beam on the tooth. This is visible blue light. If it was UV light, you wouldn't be able to see it.
Much of modern dentistry revolves around bonding; many crowns and all those white fillings are actually bonded to the tooth. Now in order achieve this bonding, you have to be able to place filling material in soft form that can be shaped, and then be able to cure or harden that shape so it's strong enough to chew on. That's how a dentist is able to make a chipped tooth look like new. This is where the light comes in.
The photo above was taken back when I was still Mr. Bhatt conducting research on curing lights. The special glasses I'm wearing allow me to safely look at the light. Fun fact, this photo is 10 years old and I still wear that yellow polo
In order to start this curing process, the filling material has to absorb blue light. The blue light is the signal to the particles in the filling material to stop doing their own thing and link together to form chains that make the filling durable enough to last thousands of meals! Now you may have heard that too much blue light is bad for your eyes. This is why many curing lights look like a ray gun or tiny flashlight, so the light stays focused on the tooth away from your eyes.
Modern dental bonding allows your dentist to fix chipped teeth like this one quickly and easily. Patients are able to smile and chew with this restoration although we caution using it to bite into hard foods like apples or peanut brittle.
So to conclude, that flashlight your dentist uses is one of the main reasons why people can have their teeth restored to what they use to look like rather than just filled with silver. It emits blue light, much like your phone or TV, not UV rays. This blue light is the secret ingredient that turns soft white filling material in a substance strong enough to last for thousands of meals. Remember, the curing light is still very powerful. Your dentist will keep the light focused inside your mouth, but just like a solar eclipse, you shouldn't stare directly at it.
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