Effective Use of Dental Curing Lights: A Guide for the Dental Practitioner

Light-cured resin-based restorations will only function as the manufacturer intends when they have received the required amount of energy at very specific wavelengths. This means that the correct irradiance, exposure duration, and spectral emission must be delivered from the light curing unit (LCU). Unfortunately, every survey of LCUs used in dental offices has shown that many of these LCUs do not provide sufficient irradiance, and the light curing techniques used by many clinicians may be ineffective. In this review article, key opinion leaders present a wide breadth of international scientific expertise in the field oflight curing. Clinically relevant guidelines are provided to help clinicians optimize their light-curing technique.The American Dental Association 2005/6 Survey of Dental Services estimates that 146 million resin restorations and sealants are placed annually.1 Almost all of these restorations use light-cured resin-based composites, hereafter referred to as RBCs. Thus, it follows that the light-curing unit (LCU) has become an indispensable piece of equipment in dental offices.While the focus of most research and education has been on choosing the appropriate RBC or LCU and on the proper handling of the restorative materials, little research has been published on the light-curing technique itself. Perhaps because light curing is perceived to be an uncomplicated procedure, the critical role of the LCU and the importance of using the proper light-curing technique are often not emphasized when teaching how to deliver successful RBC restorations. Many LCU’s in dental offices deliver an inadequate output, therefore it is very likely that many RBCs placed in dental offices are undercured2-7 and will never reach their manufacturers’ intended properties.A 2010 study using contemporary, properly functioning LCUs demonstrated that the clinician’s technique when using the LCU can make a considerable difference to the amount of energy delivered to a restoration.2 The research examined the ability of 10 dentists and 10 dental students to deliver an acceptable amount of energy (10 J/cm2) to simulated restorations in a dental mannequin. Using the same LCU for the same exposure time, there was a large variation in energy delivery among the operators: 27% delivered less than 10 J/cm2 of energy to the same Class I preparation and 82% delivered less than 10 J/cm2 to a posterior Class V preparation. If we extrapolate this scenario to a wider group, the fact that so little energy was delivered, even when using correctly functioning LCUs, may explain why posterior resin-based restorations last only a median of 5 to 7 years,8,9 when they could last 15 years or more.10In the following sections, key opinion leaders present a wide breadth of international scientific expertise in the field of light curing. These short summaries reinforce the critical role of light curing in today’s dental practice. Clinically relevant guidelines are provided to help clinicians optimize their light-curing technique so that they can safely deliver sufficient energy to their restorations. This should improve the likelihood that the RBC will achieve the manufacturer’s intended properties, and thereby improve the long-term clinical success of photo-cured RBC restorations