What is that blue light at my dentist’s office?

Blue Dental Light

Have you ever had a cavity? Hopefully you haven’t but chances are, you’ve had at least one. Maybe you’ve seen a strange looking instrument emitting a blue light while you’re sitting in the dentist’s chair. What is this blue light and what does it do? Is it dangerous?

A Strange Blue Light

The blue light we often see our dentists use is called a dental curing light. It’s used to set fillings and sealants in a matter of seconds. Halogen and LED are the two different types of curing lights, and both have been used by dentists.  The majority of dentists today use LED curing lights because they don’t overheat like the halogen lights do.  Halogen lights produce immense heat, which could potentially hurt the pulp of the tooth or the soft tissues in the mouth.

How Does it Work?

When you have a cavity, your dentist removes tooth decay with a drill and prepares the tooth for a dental filling.  The filling material, resin, is generally soft and can be moulded by biting down or by manipulating it with instruments. When the resin is exposed to this light, the material hardens and makes it strong enough for normal chewing. Resin can take anywhere from 20-60 seconds to harden using the dental curing light.

Is it Dangerous?

Since it is not a laser, the dental curing light is not dangerous to the teeth and gums. Since it is very bright, it can put a strain on your eyes if you look at it too long. This is similar to the way your eyes strain if you look at the sun for too long. Dentists and assistants know not to look at the light for long periods of time.


The dental curing light is a quick and easy way to help set your fillings so they stay secured in the tooth cavity. Learn more about fillings here!