Effect of curing-tip diameter on the accuracy of dental radiometers

The purpose of this study was to determine the accuracy of four commerciall y available radiometers when curing tips of different diameters were used. A visible-light curing unit (Optilux 500) with a new 80-watt quartz-halogen bulb (OptiBulb) was used as the light source for all measurements. The uni t's irradiance value was measured using three hand-held radiometers (Demetr on model #100, Cure-Rite model #644726, and Coltolux Light Meter) and a bui lt-in visible-light curing unit radiometer (Optilux 500). Measurements were made with four curing tips of diameters 4 mm, 7.5 mm, 10.5 mm, and 12 mm. For each tip, trials were made with five radiometers of each model. Student 's t-tests at the 0.05 level of significance were used to compare the mean irradiance measured by each model of radiometer to the irradiance value mea sured by a laboratory-grade power meter. A one-way analysis of variance at the 0.05 level of significance was used to compare the irradiance values am ong the five samples of each commercially available radiometer model. Except for the Optilux 500 built-in radiometer with the 10.5-mm tip, all th e commercially available radiometers exhibited irradiance values significan tly different from those of the laboratory-grade power meter. There were no statistically significant differences among the five samples of each comme rcially available radiometer model.