1. Impact of the distance of light curing on the degree of conversion and microhardness of a composite resin.
- Author
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Catelan A, de Araújo LS, da Silveira BC, Kawano Y, Ambrosano GM, Marchi GM, and Aguiar FH
- Subjects
- Carbon chemistry, Hardness, Humans, Light-Curing of Dental Adhesives instrumentation, Methacrylates chemistry, Polymerization, Random Allocation, Spectroscopy, Fourier Transform Infrared, Spectrum Analysis, Raman, Surface Properties, Composite Resins chemistry, Curing Lights, Dental classification, Dental Materials chemistry, Light-Curing of Dental Adhesives methods
- Abstract
Objective: This study evaluated the impact of the distance between the light guide tip of the curing unit and material surface on the degree of conversion and Knoop microhardness of a composite resin., Materials and Methods: Circular samples were carried out of a methacrylate micro-hybrid resin-based composite and light cured at 0, 2 and 4 mm distance. Monomer conversion rate was measured using a Fourier-transform Raman spectrometer and Knoop hardness number was obtained using a microhardness tester on the top and bottom surfaces. Data were statistically analyzed by analysis of variance and Tukey's test (α=0.05)., Results: Overall, the increase of curing distance reduced the microhardness (p≤0.05), but did not influence the carbon double bond conversion rate (p>0.05) of the composite resin tested; and the top surface showed better properties compared to the bottom (p≤0.05)., Conclusions: The light curing at distance can reduce mechanical properties and could affect long-term durability of the composite restorations. Thus, the use of a curing device with high irradiance is recommended.
- Published
- 2015
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