Evaluation of mechanical properties of composite resins with shelf life expired. First test: volumetric shinkrage

Rafael Avellar de Carvalho Nunes, Diogo Pedrollo Lise

Objective: To evaluate the volumetric shrinkage of different brands of composite resin 6 months after the expiration date, using a video/imaging system (Acuvol, Bisco). Methods: Composite resin increments of approximately 15μL were placed on a teflon pedestal and the initial sample perimeter was checked. After resting for 3 min, the increments were light cured and the perimeter was checked through the video/imaging and a computer software, before and after light-curing. The difference between both measurements was calculated to achieve the volumetric shrinkage percentage. Results: The mean volumetric percentage values were 2.8% for Group I, 2.66% for Group II, 2.56% for Group III, 2.58% for Group IV, 2.3% for Group V, and 2.26% for Group VI. After statistical analysis using Student t test, no significant differences were found between the groups. Conclusion: It was concluded that the volumetric shrinkage of the composites tested does not change 6 months after the expiration date.

Keywords: Dental materials. Date of validity of products. Dental restoration, permanent.

How to cite: Nunes RAC, Lise DP. Evaluation of mechanical properties of composite resins with shelf life expired.First test: volumetric shinkrage. J Clin Dent Res. 2017 Oct-Dec;14(4):67-73. DOI: https://doi.org/10.14436/2447-911x.14.4.067-073.oar

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