Clinical · Dentists
9 ways your dental curing light could be putting composite restorations at risk
Your curing light makes much of the bread-and-butter dentistry you perform every day possible, but it also carries risk. Here are nine risk factors, and how to reduce each one for better patient outcomes.
Curing lights are an indispensable tool in restorative dentistry. While your light makes much of the bread-and-butter dentistry you perform every day possible, it also poses risks. Below are nine risk factors for dental curing lights, with practical ways to reduce each one for the best possible patient outcomes.
Irradiance isn’t all that matters
Not every dentist knows their curing light intimately. But if they know just one characteristic, and one thing that can make or break a restoration, it’s the light’s output, or irradiance. Measured in mW/cm² (milliwatts per square centimeter), irradiance is a measure of the intensity of light emitted.
This is the most basic but essential characteristic of a curing light. You need to apply a certain amount of light energy to polymerize a composite material. So if your light’s irradiance is too low, and output is known to deteriorate through age and regular use, then its ability to cure materials is put at risk.
There are two things dentists should bear in mind:
- Your curing light’s irradiance may not match the stated irradiance the manufacturer provides.
- Testing your light will tell you its irradiance, but irradiance is not the only characteristic that matters.
The most reliable light in the world won't save you if you're not using proper light-curing technique.
For that reason, it’s worth going beyond irradiance alone. Read on for nine risk factors that could affect the longevity and success of your composite restorations.
1. Tip size
Tip size is critical because it dictates where the active part of your light output sits over the curing area. With a smaller light tip and a larger restoration, you might not cover the entire area that needs to be cured. To counteract this, overlap the curing areas so the whole surface receives output. Increasing the light tip size can also minimize this risk.
2. Guide angle
The guide angle dictates where the tip delivers its output. If the guide angle is too high, objects or anatomy can obstruct the light from reaching the restorative surface. You can reduce this risk by curing from the opposite angle; lower-profile guide angles also mitigate the effect.
3. Beam profile
The beam profile is the distribution of light coming from the tip. Some lights emit uniformly, but others have “hot spots” surrounded by areas of lower concentration. Moving the light and circulating between hot and cold spots can increase the uniformity of energy delivered. When using this technique, you may need to increase curing time so the entire material surface spends enough time in the hot spot to cure.
4. Wavelength
Materials contain photoinitiators that need specific wavelength ranges (measured in nanometers) to polymerize. When the light spectrum doesn’t closely match the material spectrum, the curing process becomes inefficient and you risk undercuring the composite. You can compensate for lower efficiency by curing longer, but it’s best to cure with light-and-material combinations you know are compatible. A curing-time calculator can show how your lights and materials interact.
5. Output at distance
Curing-light output diminishes with distance: the farther the tip is from the curing surface, the lower the intensity. Being aware of that distance helps you ensure the proper amount of energy reaches the material. If you can’t bring the light closer, you can increase curing time. A better solution is to test your light at both 0 mm and a clinically relevant distance such as 6 mm, for a clearer understanding of how quickly irradiance drops off.
6. Light-curing technique
The most reliable light in the world won’t save you if you’re not using proper technique. Wearing eye protection and keeping the light steady and in place are critical factors for optimal outcomes.
7. Heat concern
While you cannot overcure materials, heat damage can occur in soft tissue if you have a high-output light or are curing for prolonged periods. In these circumstances, break the curing time into multiple sessions and exposures, especially when the light overlaps the gingiva or vulnerable pulp chambers.
8. Infection control
Infection-control barriers became essential during the COVID-19 pandemic, but studies have shown they can decrease a light’s output. Test your curing light with a barrier in place to determine how it affects output, and adjust your technique to accommodate any loss.
9. Damage and debris
Scratches on the tip, damage to other parts of the light, and debris or composite stuck to the tip all decrease output. Check your light regularly for wear and tear, and clean debris from the tip before using it to cure.
Reduce these risks by knowing your numbers
Curing lights can be more complicated than they seem. The encouraging part is that many of the risk factors above can be reduced or removed once you know the exact output of every light in the practice, and whether the people holding them are delivering enough energy to cure.
Curing-light evaluations recorded across the Bluelight platform: the data behind knowing which lights, and which operators, are a risk.
A CheckMARC evaluation lets a clinic measure output and store results automatically, with curing times tailored to specific light-and-material combinations. To go further, measuring every curing light and every operator in the clinic, and pinpointing exactly where the risk sits, a CheckMARC evaluation closes the loop between the light, the technique, and the restoration.