According to the American Dental Association, nearly 150 million resin-based restorations and sealants are placed every year. Almost all of these use light-cured resin-based composites. Thus, a light-curing device is now commonly found in dental practices across the country. Some assume that a “point and shoot” technique is sufficient. However, in order to achieve optimal results, dental curing lights must be used correctly.
In the dental field, a curing light can use ultraviolet or visible light, depending on what it is designed for. Both dentist and patient need to wear eye protection to limit damage to the retina for even the 20 seconds to a minute that the light is in use during rapid curing, and the light needs to be well maintained so that it will work properly and effectively. It’s also important to use the right curing light for the right resin product; many lights are designed to handle a range of resins safety.
Using a curing light accomplishes two things. In the first place, it makes sure that the resin cures properly and adheres evenly. When applying fillings, this is critical to keep the filling in place in the mouth. For sealants, the curing light limits the risk of cracks and other problems with the sealant. With adhesives for implants( dental implant motor ) and braces, the rapid, even cure is also designed to limit problems in the future.
How a dentist uses a light-curing unit makes a large difference in the amount of energy a restoration receives. Even when the device is handled correctly, if the energy level is insufficient, then the resulting restoration may not attain expected longevity; this may explain why resin-based restorations last only five to seven years when actual life expectancy should be 15 years or more.
Both light intensity – or irradiance – and the dental application should factor into a dentist’s decision regarding his or her choice of curing light. For instance, irradiance is measured by calculating power output, or milliwatts (mW), of a curing light across the surface area of the curing light guide. A curing light must deliver a minimum irradiance of 400mW/cm2 for a time interval to adequately polymerize a 1.5-2mm thick resin composite.
Clinicians also should consider the clinical application at hand. It has been documented that irradiance of curing lights attenuate/decrease significantly when it passes through restorative materials, such as ceramic restorations or resin composites. The percentage of decrease in irradiance depends on filler type, filler loading, shades, refractive index, opacity, translucency and thickness of restorative materials. Curing lights with high irradiance compensate for the decrease in the loss of total energy and allow dentists to cure resin composites completely. In general, an irradiance of 1000mW/cm2 or higher is considered ideal to cure resin-based materials through indirect restorations.