It may seem like a crazy thing to do, but in the past uranium was added to dentures to help them look more attractive. Denture teeth had a big problem: they didn’t fluoresce the way natural teeth do, and uranium gave them that quality.
Why Fluorescence Matters
Fluorescence is when a material that’s hit by invisible light (typically ultraviolet light, such as is produced by black lights) produces visible light as a result. Our natural teeth do this in the dentin, the darker layer inside the teeth. If your denture teeth don’t fluoresce, they won’t look natural.
You might think this only matters if you are going to a nightclub or playing glow-in-the-dark golf, but it’s actually important any time you’re outside in natural light. Sunlight contains ultraviolet light in addition to visible light, so natural teeth actually glow in sunlight. That means that if your denture teeth don’t fluoresce, they will look duller and greyer in the sun.
Uranium for Fluorescence
The first patent for making dental teeth that fluoresce was filed in 1942 using the wonder material of the age — uranium. Because uranium is naturally fluorescent, it seemed a reasonable choice. And at the time, few people really understood the problems with radiation exposure. It was a relatively new phenomenon.
However, over the years as we began to realize the link between radiation exposure and cancer, people began to wonder how significant this source of radiation was. One study estimated that people would be exposed to 66 rem at the surface of their mouth and up to 0.21 rem each year at the layer of sensitive basal cells which can be damaged by radiation, increasing cancer risk.
Another study estimated the dosage was closer to 600 rem per year . For comparison, the total background radiation exposure for a person in South Carolina is estimated at about 0.32 rem. That means that your mouth would be bombarded by something like 200-2000 times the total background radiation exposure to your entire body. It’s no surprise that people stopped supporting the use of uranium in the mid 1980s when these figures came out!
Fluorescence in Denture Teeth Today
Today, uranium is not used in dental porcelain or in dentures at all in the US.
With cheap dentures, the teeth are made of the same PMMA plastic that is used in the denture base. PMMA is one of the least fluorescent plastics, so these teeth can look dull in sunlight and won’t show up in black lights.
Quality dentures use ceramic teeth that have the fluorescence of natural teeth so they look bright in sunlight and natural under black light conditions. They don’t have uranium. Instead, fluorescence is given by the use of rare earth elements that aren’t radioactive.
This is just another way that quality dentures outshine their cheap competitors. If you want to learn more about natural-looking dentures, please call (803) 781-9090 for an appointment with a Columbia, SC denture dentist at Smile Columbia Dentistry.
