Light curing unit effectiveness assessed by dental radiometers

Objectives: The purpose of this investigation was to assess the effectiveness of five commercially available hand-held dental radiometers and a computer-based experimental radiometer. Methods: Light intensity of five visible light activation units was determined using the dental radiometers. The influence of curing light intensity on depth of cure of a hybrid composite material was determined using a digital penetrometer. Results: The radiometers evaluated varied with respect to sensor aperture diameter, scale readings (analogue or digital) and the units of measurement (arbitary or mW cm2). The experimental computerbased radiometer allowed continuous recording of intensity against time; thus the light output could be monitored over the entire irradiation period. Conclusions: When light intensity readings were normalized with regard to a standardized light sensing device aperture of 4 mm diameter, a linear relationship was found between depth of cure and the logarithm of the intensity of the light. The results of this investigation support the use of dental radiometers for periodically monitoring visible light activation units.