Effect of exposure time vs. irradiance on knoop hardness of dental composites

Materials Research

Américo Bortolazzo Correr¹  Mário Alexandre Coelho Sinhoreti¹  Lourenço Correr-sobrinho¹  Rubens Nisie Tango¹  Simonides Consani¹  Luis Felipe Jochins Schneider¹ 

[1] ,UNICAMP Piracicaba School of Dentistry Piracicaba SP ,Brazil

关键词: composite resin;    energy density;    Knoop hardness;    light curing;   

DOI  :  10.1590/S1516-14392006000300006

来源: SciELO

【 摘 要 】

A comparison was made of the hardness of Z250 and Esthet-X composites light cured with different light sources. Cavities (3 mm diameter x 6 mm deep) were prepared in 240 bovine incisors. The composite was bulk inserted and light-cured using halogen light, LED or xenon plasma arc (PAC) with different irradiances and exposure times, maintaining the same energy density. The specimens were stored in an incubator at 37 °C for 24 hours prior to sectioning for hardness measurements. Three measurements were taken at each depth: surface, 1, 2, 3, 4 and 5 mm. The data were analyzed by ANOVA and Tukey's test (p < 0.05). No statistically significant differences were found for LED up to 2 mm, for PAC up to 3 mm, and for halogen light up to 5 mm. Photoactivation with intermediate power density and exposure time resulted in the highest Knoop hardness values.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License