How infection-control barriers impact dental curing light performance

Curing lights are used in more than half of a dentist's procedures (1). Because they are handled so often, in close proximity to so many patients, they are a high-risk surface for cross-contamination, exposed every day to blood, saliva, respiratory particles, and the dental materials that cross-contaminate easily.

Infection-control barriers solve that problem. They are convenient, non-invasive, and prevent contact between the oral tissues and the light tip, and they keep uncured resin off the tip too. The Centers for Disease Control and Prevention categorize light-curing units as a semi-critical instrument, for which infection control is essential. Since curing lights cannot be sterilized, disposable infection-control barriers (ICBs) are the most common solution.

But there is more to consider than simply using a barrier or not. Barriers come in different designs and materials, and the question dentists should be asking is this: does placing a barrier on the tip change how the light performs? If it does, it has direct implications for curing times and the success of restorative procedures.

Do barriers impact curing light performance?

When resin sticks to the tip of a curing light, estimated to happen in 35–68% of units in dental offices (5), it can reduce the light's output and impair its ability to polymerize composite. So it should come as no surprise that covering the tip for infection control can affect performance too.

A study by Soares, Braga, Ribeiro, and Price, Effect of infection control barriers on the light output from a multi-peak light curing unit (2), investigated exactly how much impact barriers really have. The researchers tested a high-powered, multi-wave LED curing light with six different commercially available ICBs, measuring the light's radiant power, irradiance, emission spectrum, and beam profile.

Each barrier was tested when positioned correctly, a smooth, transparent face over the tip, and again with several incorrect placements, with seams or opaque sides obscuring the tip, to simulate the realities of a busy operatory.

What they found was that regardless of placement or barrier type, infection-control barriers significantly reduced the radiant power emitted by the curing light by 5–16%. The barriers also impacted performance more severely when applied incorrectly, lowering light output by up to 26%.

Here is what else the study found:

• The worst incorrect usage was a wrinkled barrier surface. This reduced radiant power by 14–26% across all six barrier types.
• Polyethylene and polyvinyl chloride-based barriers had less impact on light performance than the one latex barrier tested.

What this means for your restorations

These findings matter. If you are using a barrier with your curing light, you are likely applying less power than normal to your composite, and if the barrier is placed incorrectly, the energy reaching the material could be lower still. Without knowing your light's actual output and adapting curing times accordingly, you risk undercuring and compromising your restorations.

For context, a 2018 study in Germany found that fewer than a third of dental offices used disposable barriers (3). In Bluelight's own database of dentists using our CheckMARC service, we have seen a 20% increase in curing-light tests completed with a barrier in place (4), so this is an increasingly common, and increasingly important, variable to control for.

How to use barriers and still cure effectively

Dentists face a genuine tension: barriers are necessary to reduce the risk of contamination, yet they tend to decrease curing-light output and raise the risk of an incomplete cure. The study's authors suggest a practical path through it:

• Use a barrier to keep disease and debris off your light.
• Apply it correctly: no folds, seams, or wrinkles over the tip.
• Test your light regularly, and test it with a barrier in place to see how the output changes.
• Adjust your curing times to compensate for power loss.
• Make sure the light is emitting enough power to begin with; low-powered or inconsistent units can be hit harder by a barrier.
• Use protective glasses and keep the tip perpendicular to the restoration surface for maximum efficiency.

The throughline is measurement. Testing your light both with and without a barrier tells you exactly how it is performing and how much its output changes, so you can adapt your technique for better patient outcomes. A CheckMARC evaluation makes that routine, giving you optimal curing times for your materials by measuring your light's output, with or without a barrier in place. Whatever light, material, and barrier combination you choose, you can be confident you are giving your restorations the best chance of success.