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Brazilian Journal of Oral Sciences
Piracicaba Dental School - UNICAMP
EISSN: 1677-3225
Vol. 8, No. 1, 2009, pp. 30-33
Bioline Code: os09006
Full paper language: English
Document type: Research Article
Document available free of charge

Brazilian Journal of Oral Sciences, Vol. 8, No. 1, 2009, pp. 30-33

 en Knoop hardness of composites cured with halogen and led light-curing units in class I restorations
Giorgi, Maria Cecília C.; Maffei, Luís Alexandre & Paulillo, Sartini

Abstract

Aim: To evaluate the effect of light-curing units (LCUs) on the microhardness of class I composite restorations at different depths.
Methods: Two light emitting diodes (LED) (Freelight 2, Radii) and one halogen (Optilux 501) LCUs were evaluated. Thirty class I cavities prepared in human third molars were restored with a microhybrid (Charisma) and a microfilled (Renamel) resin composite. After seven days of water storage, the teeth were decoronated and the crowns were bisected mesiodistally and tested for microhardness under a 25 g load for 20 seconds. Fifteen indentations were performed at three depths for each half-crown.
Results: Charisma presented significantly higher Knoop hardness number (KHN) values than Renamel. At the superficial depth, there were no statistically significant differences (p > 0.05) when Charisma was cured with both LED curing units. However, statistically significant difference (p < 0.05) was found when Charisma was light-cured with the halogen LCU. The lowest KHN value was obtained by Renamel light-cured with both LED LCUs, regardless of the composite. Nevertheless, when the microfilled composite was light-cured with the halogen LCU, hardness was significantly higher compared to those cured with LED units at all evaluated depths.
Conclusions: The effectiveness of polymerization is related not only to the light-curing source, but also to the type of composite and the curing depth.

Keywords
composite resins, hardness

 
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