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Brazilian Journal of Oral Sciences
Piracicaba Dental School - UNICAMP
EISSN: 1677-3225
Vol. 6, No. 22, 2007, pp. 1372-1375
Bioline Code: os07024
Full paper language: English
Document type: Research Article
Document available free of charge

Brazilian Journal of Oral Sciences, Vol. 6, No. 22, 2007, pp. 1372-1375

 en Thermocycling effect on microhardness of laboratory composite resins
Pereira, Sarina Maciel Braga; Castilho, Anderson Almeid; Salazar-Marocho, Susana María; Oliveira, Karla Mychellyne Costa; Váquez, Vanessa Zulema Ccahuana & Bottino, Marco Antonio

Abstract

The aim of this study was to evaluate the thermocycling effect on microhardness of laboratory composite resins. 30 disks were fabricated, 5 mm of diameter and 2mm of width, using 3 laboratory resins: G1 (n=10) - RESILAB MASTER (Wilcos-Brasil), G2 (n=10) - Vita VMLC (VITA Zahnfabrik-Germany), and G3 (n=10) - Vita Zeta (VITA Zahnfabrik-Germany). Vickers microhardness (HV) of all specimens was evaluated using a microhardness tester FM-700 (Future Tech- 50 g/10s). The specimens were measured before and after the thermocycling (3.000 times and 12.000 times - 5° /55°C±1). The microhardness values before cycling were (mean±SD): G1: 55.50±4.6; G2: 35.54±2.5; G3: 27.97±1.6.; after 3.000 thermocycles: G1: 55.54±3,9; G2: 29.92±2,73; G3:21.01±1.4 and after 12.000 cycles G1:54.27±3.2; G2: 30.91±1.6. G3: 23.81±0.9. Variance analysis (ANOVA) and Tukey's test was accomplished (p<0,05), the highest microhardness values were observed in G1; G2 and G3 showed reduction of microhardness values. It was concluded that, after thermocycling, the tested laboratory composites resins are susceptible to the decrease of surface microhardness.

Keywords
composite resins, microhardness, thermocycling

 
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