Adventures in curing

March 21, 2012

In case your missed it, this adhesive dentistry thing is starting to catch on. Of course I’m kidding, but when was the last time you heard “bonding doesn’t work?” Adhesive dentistry has pretty much become the gold standard these days with many of us not even sure of the last time we placed a restoration that wasn’t bonded into place. However, like everything else in dentistry, attention to detail is paramount in the recipe to ensure the longevity of bonded restorations.

In case your missed it, this adhesive dentistry thing is starting to catch on. Of course I’m kidding, but when was the last time you heard “bonding doesn’t work?” Adhesive dentistry has pretty much become the gold standard these days with many of us not even sure of the last time we placed a restoration that wasn’t bonded into place.
However, like everything else in dentistry, attention to detail is paramount in the recipe to ensure the longevity of bonded restorations.

While issues such as “wet bonding” (thanks to Dr. John Kanka) and proper isolation are important, one step is frequently taken for granted…the step of proper curing. It’s often a given in our profession that a curing light is a curing light, but frequently nothing can be further from the truth. For without proper curing, all of our other efforts to ensure the longevity of bonded restorations are really pretty much in vain.

Curing troubles

The problems with curing and bonding really break down into two areas. One is directly related to the intensity of the light. Without a proper intensity of the curing light, we cannot expect the material to cure properly. This affects depth of cure as well as simply not setting even very thin layers adequately.

The other deals with the thickness of the composite. While some new materials are being indicated for “bulk fill” (more on that in a future article), most materials are still being indicated by manufacturers as “incremental.” This means these materials should be placed in 2-3 mm increments.

If you place darker colored composite in increments that are in excess of 2-3 mm you run the risk of uncured material…which will be on the floor of the prep. This causes sensitivity and will be even worse if the light intensity is not adequate. You can overcome some of this with a high intensity light, but you still need to remember that the more material there is, the harder it is for intense light to pass all the way through.

Curing advice

My first recommendation is to buy a good radiometer and check your lights on a regular basis. Kerr (kerrdental.com) has one for halogen lights and one for LED lights. Monitoring your lights on a daily or weekly basis is an easy way to ensure your lights are providing proper curing.

My second recommendation is to use some type of barriers on your lights. Besides preventing cross contamination, this keeps bonding agent and composite from becoming cured on the tip. As this debris accumulates on un-sleeved lights, the tip becomes like the windshield of my SUV on a summer drive. Lots of junk on the tip will keep light from getting to the composite. Just peel off the barrier and throw it away. Problem solved.

Bright lights

And now lets take a look at three of the devices that are currently available to you.

SmartLite MaxDENTSPLY Caulk

The SmartLite Max features Standard, Pulse, Boost and Ramp modes with an output of 1,200 mw/cm2 in Standard Mode and 1,400 mw/cm2 in Boost mode. It can be used cordless or, if someone forgets to charge it, it can be used with an AC cord. It also has a nice display screen on the device that provides all necessary info.
This unit, and the last one in this article, both have unique LED arrays. Although there are not many, there are a few materials on the market that don’t use camphoroquinone as the photoinitiator. To combat this problem, the SmartLite Max (and the Valo mentioned later) both have an LED array that uses LEDs with different wavelengths from 400 nm-470 nm. This ensures all composites can be set.

DemiPlusKerr Corp.

The DemiPlus features a unique concept of pulsing their LEDs. Termed “Periodic Level Shifting” this patented technology means for every ¼ of each one-second exposure, the light’s output shifts from high to even higher in a constant pulsing pattern. This gives the device the ability to provide high intensity output without damaging the LEDs by overheating. The device features a standard output of 1,100 mw/cm2 while the pulses deliver an output up to 1330 mw/cm2.
The light guide is extended, which translates to a 28% increase in reaching areas in the posterior. It features time modes of 5, 10 and 20 seconds, has a low battery indicator, and can provide 500 five-second cures on one charge. The battery can be fully recharged in only 3 hours.

Valo Cordless Ultradent

By the time you read this, Ultradent’s latest curing light, the Valo Cordless, should be available. The original Valo was brought to market in 2008, and while a terrific light, required an AC cord. This was necessary because of the small diameter of the device and the power demands caused by the intensity of the output. However, Ultradent has continued to press onward with research and is now able to provide all of Valo’s advantages with the added plus of it being cordless. The device features outputs of Standard with 1,000 mw/cm2, High Power with 1,400 mw/cm2 and Xtra Power with 3,200 mw/cm2.

The device (like the SmartLite Max above) features an array of different wavelength LEDs that allow it to cure any composite on the market. It also is made of aircraft grade aluminum and is very durable to drops and the wear and tear of every day use due to this and a special sapphire finish.

The Valo is powered by two batteries and comes with an extra set standard. These extra batteries are charged via a separate charger (included) and will fully charge in 1-3 hours. In case of an emergency where more batteries are needed, Ultradent includes a list of authorized alternate batteries that can be purchased from battery distributors.

Conclusion

Curing is critically important to bonded restorations. Attention to details-including using the best curing light possible-will definitely allow you to provide superior restorative services to your patients.

About the author

John Flucke, DDS, is Technology Editor for Dental Products Report and dentistry’s “Technology Evangelist.” He practices in Lee’s Summit, Mo., and has followed his passions for both dentistry and technology to become a respected speaker and clinical tester of the latest in dental technology, with a focus on things that provide better care and better experiences for patients. He blogs about technology and life at blog.denticle.com.