The most common type of dental curing light is an LED. This classic type of light was designed to polymerize a specific photoinitator called camphorquinone (CoQ), which is most effectively polymerized at around 480nm. The light guide is designed to deliver a high concentration of light at this exact wavelength. Int he years since then our resin materials have changed and today we deal with 4 different photoinitiators. The light wavelength to most efficiently polymerize this newer chemistry may be around 390-405nm, or still int he range of 450-480nm. Today a new type of LED light referred to as "polywave" delivers two separate wavelengths of light.