Abstract

GRAU GRULLON, P.; PORTERO, P.P.; LAUFER-NETO, J.  and  GOMES, O.M.M.. Polymerization of dual-cure resin luting cements through laboratory-processed-resins: LED versus halogen lights. Av Odontoestomatol [online]. 2008, vol.24, n.4, pp.261-265. ISSN 2340-3152.

This study evaluated the influence of indirect composite resin thickness, the storage time and light-curing units on the Vickers hardness of a dual-cure resin luting cement. Two light-emitting diodes lights (Optilight CL [CL] and UltraLume5 [UL]) were compared with a quartz tungsten halogen unit (Optilux 401 [OH]). Laboratory-processed composite specimens with a diameter of 5mm and thickness of 1 and 2 mm were constructed to be interposed between the light guide and the metal matrix (5mm wide and 0.5 mm deep) with the resin luting cement. Then, 45 dual-cure resin luting specimens were divided in nine groups: G1: direct light exposure DLE/OH; G2: 1 mm/OH; G3: 2 mm/OH; G4: DLE/CL; G5: 1 mm/CL; G6: 2 mm/CL; G7: DLE/UL; G8: 1 mm/UL and G9: 2 mm/UL. The light curing was performed for 60 seconds. The Vickers hardness (50g/30s) was measured at the top surface of all specimens, either after 24 hours or 180 days. The Light-curing unit and the Composite thickness were statistically significant (p<0.05). The CL light curing unit produced the lowest mean hardness values; no significant difference was observed between OH and UL. No significant effect of storage time was observed. The thickness of the laboratory-processed resin and the light curing unit can influence the hardness of the resin luting cement.

Keywords : Composite resin; hardness; resin luting cements.

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