In the dental field, a dental 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.

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.

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.

Light Emitting Diode (LED) curing lights. These curing lights use light-emitting diodes (LEDs) as a light source and do not require filters. The original LED lights had narrow emission spectrum and low power intensities, necessitating long curing times. This issue was overcome by 2nd generation curing lights with high power intensity. However, they maintained narrow emission spectrum, which restricted them to activate only camphorquinone, and thus could not fully polymerize some composite materials.

Manufacturers of dental curing lights make models which are designed to be sterilized between patients, with controls which allow the dentist to adjust focus and intensity. Replacement bulbs, special filters, and other fixtures are usually available through dental supply catalogs. When purchasing a curing light, it is advisable to go through reviews in trade publications and to talk to practicing dentists to get product recommendations and performance ratings.