The selection of a dental curing light that fits your style of practicing remains one of the most important equipment purchases you will make. If you have an active restorative practice, it is a device that you use virtually every time you treat a patient. The right light can help you achieve success, while the converse is true – the wrong light can make your efforts more tedious and your results less consistent.

Curing lights provide light energy of an emission spectrum. Photo-initiators absorb this light energy and initiate chemical reactions to polymerize a composite material. This process is called photo-polymerization.

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.

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.

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 and braces, the rapid, even cure is also designed to limit problems in the future.

The dental curing light also increases patient comfort by rapidly curing resins so that the patient is not forced to sit in discomfort while the resin sets. Since the mouth usually needs to be held open wide and may be dry for the procedure, patients usually want the procedure to end as quickly as possible so that they can close their mouths and remoisturize the dried oral membranes. Using a curing light gets patients in and out of the portable folding chair quickly so that the experience of irritation and pain is limited.

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.