Abstract |
The aim of this study was to evaluate the effect of the increase of energy density on Knoop hardness of Z250 and Esthet-X composite resins. Cylindrical cavities (3 mm in diameter X 3 mm in depth) were prepared on the buccal surface of 144 bovine incisors. The composite resins were bulk-inserted and polymerized using different light-curing units and times: conventional QTH ( quartz- tungsten- halogen; 700 mW/cm(2); 20 s, 30 s and 40 s); LED (light-emitting diode; 440 mW/cm(2); 20 s, 30 s and 40 s); PAC ( xenon plasma arc; 1700 mW/ cm(2); 3 s, 4.5 s and 6 s). The specimens were stored at 37 degrees C for 24 h prior to sectioning for Knoop hardness assessment. Three measurements were obtained for each depth: top surface, 1 mm and 2 mm. Data were analyzed statistically by ANOVA and Tukey's test (p<0.05). Regardless of the light source or energy density, Knoop hardness of Z250 was statistically significant higher than that of Esthet-X (p<0.05). Specimens cured with PAC had lower hardness than those cured with QTH and LED (p<0.05). Higher Knoop hardness was obtained when the energy density was increased for LED and PAC (p<0.05). No statistically significant differences (p>0.05) were found for QTH. Knoop hardness values decreased with the increase of depth. The increase of energy density produced composites with higher Knoop hardness means using LED and PAC.
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Authors | Américo Bortolazzo Correr, Mário Alexandre Coelho Sinhoreti, Lourenço Correr Sobrinho, Rubens Nisie Tango, Luis Felipe Jochims Schneider, Simonides Consani |
Journal | Brazilian dental journal
(Braz Dent J)
Vol. 16
Issue 3
Pg. 218-24
( 2005)
ISSN: 1806-4760 [Electronic] Brazil |
PMID | 16429188
(Publication Type: Journal Article)
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Chemical References |
- Composite Resins
- Dental Materials
- Esthet-X
- Filtek Z250
- Polymers
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Topics |
- Animals
- Cattle
- Composite Resins
(chemistry, radiation effects)
- Curing Lights, Dental
(classification)
- Dental Cavity Preparation
(methods)
- Dental Materials
(chemistry, radiation effects)
- Hardness
- Light
- Light-Curing of Dental Adhesives
(methods)
- Polymers
(chemistry, radiation effects)
- Surface Properties
- Temperature
- Time Factors
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