Why is this type of dental technology so underappreciated?
The curing light is as important to clinical success as a handpiece—so why is it so often overlooked?
Here's a clinical scenario: an anterior composite is about to be done on a Class IV fracture. When completed, it will be visible to others. Before starting, chances are you will take a couple of photos and spend at least a few minutes performing a shade match with you and your assistant, and evaluating the surrounding teeth to help you determine anatomical shape, etc.
Once all those steps are completed, you then prep, which could be affected by esthetics, and restore. When the procedure is complete you will proudly take a couple of after photos so that you have a record of your good work. Unfortunately, a few days later the patient calls to say the restoration has “come off.” You silently curse the dental gods knowing you’ll be doing the whole procedure again… only this time for free.
Here’s another clinical scenario: A posterior composite is done replacing an old occlusal amalgam restoration. You do everything by the book. You’re happy with the results. A week later, the patient calls saying they are having pain every time they bite on the tooth. The front desk tells them that it is most likely needing a bite adjustment, but at the follow-up appointment, the occlusion looks perfect. You decide to check it with a Tooth Slooth and it only responds to pressure on the restoration.
Both of those scenarios are ones that are seen in offices all over the world daily. When troubleshooting these types of problems, there are several things to consider as the single or contributory cause, but how many of you would consider your curing light?
In my lectures, I often refer to curing as “the stepchild of adhesive dentistry.” That’s because even though it’s always around, no one pays it very much attention. However, if your restoration isn’t properly cured, it is doomed to fail.
An improperly cured composite can have more “give” along the pulpal floor which can cause pressure differentials along the dentinal tubules when occlusally loaded. This can cause (though it is not the only culprit) the dreaded “pain upon biting” problem. Improperly cured composites can also lead to marginal degradation and even fracture of the material.
There are several factors to take into consideration when thinking about how curing affects your restoration. It’s not just a matter of holding the light over the composite.
The first thing is your light intensity. Do you really know how strong your curing light is? Most lights currently on the market are very strong, putting out around 1000mw/cm2. However, that intensity can drop over time for a variety of reasons. If you are not monitoring your lights on a regular basis and checking their output, your curing is nothing better than a roll of the dice. Most manufacturers like to see a minimum of 800mw/cm2, but I’m a fan of the previously mentioned 1000mw/cm2.
The intensity of the beam allows for deeper penetration of the photons into the material. However, remember that darker colors absorb more so they must be placed in thinner layers and cured using more cycles. Conversely, lighter colors allow for greater depth of cure and can be placed in thicker layers.
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