How to know if you’re using the right curing light?

3M ESPE scientist Joe Oxman said it’s important to realize your materials and your curing light need to work together properly to make sure your patients get the best possible care.

Not only do you need to understand how the various restorative materials handle and how they work for different procedures, it’s also key to stay on top of what curing lights work best with what material and exactly what it takes to ensure you get the best results.

3M ESPE scientist Joe Oxman said it’s important to realize your materials and your curing light need to work together properly to make sure your patients get the best possible care.

“If you don’t cure it properly you can end up with reduced properties, you can end up with more staining, more extractables, so adequate curing is really the key to success,” said Oxman, who has worked at 3M ESPE for three decades.

“Traditionally there had been two limitations with materials: No. 1 it was challenging to get sufficient curing from top to bottom; so to try and cure something from top to bottom 4 mm was challenging. But the bigger issue is that when these materials undergo their curing or hardening process is they tend to shrink.’

“The problem that you run into is if the materials exhibit too much shrinkage then the more material you place the more potential issues that you could have in terms of the material not anchoring well or adhering well to all the walls of the tooth structure.”

Because of this, Oxman said it takes a lot of research before you understand how materials and curing lights work together. Companies also need to conduct plenty of tests before launching new dental restoratives and curing lights. Numerous studies need to be conducted before researchers determine that products like bulk fill materials will deliver strong restorations.

A decade ago halogen lights were quite popular in the industry, but the shift to LED lights is reflected by DPR ‘s latest survey. Almost six in 10 respondents (59%) now use an LED curing light, while 17% use a halogen light (22% use a combination of both types in their practice).

“LEDs provide the benefits of being energy efficient. They don’t need to be replaced, they have high output and they provide the ability to use a battery-operated source,” Oxman said.

“So there’s going to be some continued advancements in the lights, but the lights by themselves don’t serve a useful purpose without the materials, and the material by itself isn’t useful without the lights. It’s the combination of the two—it’s the system that’s critical to the end result.”

Dr. Daniel Ward said it is important to understand how your curing light works with a variety of today’s materials.

As is always the case, following manufacturer instructions is a key step that should not be overlooked. He added, however, that information is not always easily accessible when you’re working with numerous products and are unclear of how exactly each one will interact with your curing light.

“It is not always easy to ascertain the photoinitiators employed for a particular brand and/or shade of composite,” Dr. Ward said. “It is certainly not printed on the side of the composite syringe nor prominently listed on the directions for use (DFU).’

“Some composite materials may use different photoinitiators within the same brand of materials. The most common used photoinitiator is camphoroquinone, which is yellow in color.

“Companies often use dif ferent initiators in their translucent incisal shades to allow for a more clear-blue/gray color,” added Dr. Ward, who has lectured at the Post-Graduate Programs in Esthetic Dentistry at the University of Minnesota, SUNY Buffalo, UMKC , and the University of Florida and served as chief examiner.

“Recently new photoinitiators have been introduced that are more sensitive to light output, allowing for a deeper depth of cure. It is better to use a curing light that emits multiple wavelengths of light; 470 nm blue light, which cures camphoroquinone, and 390-435nm purple light, which cures many of the other photoinitiators used. Light output is very important. The latest generation of LED lights have incredible energy output to ensure that the material is adequately cured for optimal performance.”

Oxman warns, however, that some materials require a minimal amount of curing time even when high intensity lights are used. He suggests clinicians make sure the cure is complete before moving on to the next step.

“Really the take-home message now from a number of researchers is that the exposure time is more important than the intensity. I’m not saying the intensity isn’t important, but if you really step back the studies are saying you really need to have a certain amount of light exposure,” Oxman said.

“Again it’s going to vary depending on the shade of the material and the optical properties. The message is that there is some limitation with the chemistry. You need to cure it effectively at the top and you need to cure it effectively at the bottom and that there’s some kind of minimum light exposure.”

Dr. John Comisi suggests dentists shop around when considering a curing light purchase as today’s options offer up a wide range of features.

“First they need to know what the energy output of the light happens to be, and how the energy is maintained as the light is further and further from the deepest aspect of the preparation,” he said.

“Second will it cure all materials? Is the wavelength of the light output going to do the job? Third can the light’s battery be replaced, and if so is it at a reasonable cost? All batteries eventually will need to be replaced since they will lose the ability to recharge after a period of time. If the cost is high, then that becomes a consideration in purchasing the device. If the battery cannot be replaced, then the entire device will need to be discarded and a new one purchased. These costs are important to keep in mind.”

According to our survey, dentists are clearly aware of the importance of curing lights. When we asked how important the quality of your curing light is in ensuring proper results in restorative procedures — on a scale of 5 for very important and 1 for not important at all — 74% checked 5 (most important) and 20% checked 4 (next most important).

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