Objective, the aim of this investigation was to determine effect of high-intensity light curing on hardness and depth of cure (DC) of a composite and their correlation. Methods, Charisma shade A20 (Kultzer) was employed. Three cylindrical specimens 3 X 6 mm were prepared for each of 7 light intensities (110, 266, 425, 625, 836, 1009 and 1295 mW/cm2). Two light curing units (Spectrum 800, Dentsply and Optilux 501, SDS/Kerr) were used. Light curing (LC) was applied for 5, 10, 15, 30 & 40 s. Light was applied from top end only and specimens were scraped to remove soft material from other end. Specimen length was measured and DC values were calculated as ½ measured length. Groups of 2 disc specimens were prepared from same material for Knoop hardness number (KHN) measurements at each light intensity and curing time as above. Three KHNs were obtained from each specimen. Mean KHNs and DC values were determined. Results, at 425 mW/cm2 mean KHNs were: 9.4, 15.9, 19.5, 26.9 at LC of 5, 10, 15 & 30 s, respectively. While at 1295 mW/cm2 mean KHNs were: 18.6, 30.4, 37.2, 44.8 & 49.9 at LC of 5, 10, 15, 30 & 40 s, respectively. At 425 mW/cm2 mean DC values were: 1.6, 1.81, 2.0 & 2.5 at LC of 5, 10, 15 & 30 s, respectively. While at 1295 mW/cm2 mean DC values were: 2.44, 2.81, 3.17, 3.4 & 3.62 at LC of 5, 10, 15, 30 & 40 s, respectively. Increasing intensity from 425 to 1295 mW/cm2 resulted in an increase in KHN ranging 67–98% and in DC ranging 45-59%. Conclusions, a positive correlation was found between DC and KHN with increasing light intensity, however, the effect was more pronounced with KHN than with DC. Supported in part by Dentsply Canada, SDS/Kerr.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

Top Level Search