| 1609 Influence of techniques and photoactivation methods on composite Knoop hardness | ||
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L. CORRER-SOBRINHO1, A.B. CORRER1, R.L.X. CONSANI1, E.B. ALVES1, R.M. PUPPIN-RONTANI1, M.A.C. SINHORETI1, and J.C. KNOWLES2, 1State University of Campinas, Piracicaba - SP, Brazil, 2Universitity College London, United Kingdom Objectives: The aim of this study was to evaluate the influence of three techniques and photoactivation methods on Knoop Hardness Number of a Filtek Z250 (3M/ESPE) composite. Methods: Ninety cavities were prepared in the buccal surface of bovine incisor teeth (3mm mesio-distal; 3mm incisive-cervical, and 1.5mm depth) with dentine margins. The groups were divided according to the photoactivation techniques (n=10): direct, transdental or mixed (transdental followed by direct), and methods of photoactivation: halogen light (XL 2500 -3M/ESPE), with 600mW/cm², xenon plasma arc (Apollo - 95E/DMD) with 1340 mW/cm² and light emitting diodes - LED (Ultrablue Is/DMC) with 500mW/cm². The restoration with composite Filtek Z250 was photoativated for 20 seconds with XL 2500 and Ultrablue Is (LED), and 9 seconds with Apollo 95E curing units. All specimens were stored in distilled water at 37°C for 24 hours. Afterwards, the specimens were submitted to Knoop Hardness test using HMV 2 microhardness machine (Shimadzu), with a load of 50g applied for 15 seconds. Six measurements were made for each specimen. The data were submitted to ANOVA and Tukey's test (α=0.05). Results: The Knoop Hardness Number for the photoactivation methods Ultrablue Is (LED), XL 2500 and Apollo 95E within photoactivation techniques were: direct = 95.30, 96.21 and 87.35; mixed = 88.63, 87.11 and 86.54; transdental = 63.21, 58.25, 56.51. The direct photoactivation showed the Knoop Hardness Number statistically higher than mixed and transdental techniques. Independent of photoactivation technique, the Ultrablue Is (LED) curing unit showed the Knoop Hardness Number statistically higher than Apollo 95E. No statistical difference was found in the Knoop hardness number between the Ultrablue Is (LED) and XL 2500, and XL 2500 and Apollo 95E curing units. Conclusion: The direct photoactivation technique and Ultrablue Is (LED) photoactivation method showed the higher Knoop hardness number.
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| Seq #186 - Mechanical Properties 3 2:00 PM-3:15 PM, Friday, March 23, 2007 Ernest N. Morial Convention Center Exhibit Hall I2-J | ||
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Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program
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