In vitro microhardness evaluation of bulk fill resins after six months of water storage

Simone Maria Bonfanti Henkes, Almir José Henkes, Fernanda Zanella Arruda, Marcos Alexandre Fadanelli, Vicente Castelo Branco Leitune, Fabrício Mezzomo Collares

Introduction: Bulk fill resins provide a reduction in clinical time during the confection of a restoration, by permitting the polymerization of larger increments compared to conventional resins (4 to 5 mm). Objective: The aim of this study was to verify the bulk fill and conventional resins Knoop microhardness immediately and after 180 days stored in a solvent. Methods: 24 samples were divided into four groups: Z2 (control with conventional resin), AB (Aura Bulk fill), TB (Tetric Bulk fill) and FB (Filtek Bulk fill). The Knoop microhardness (KHN) was measured at top and bottom of the samples. Results: The KHN obtained for top after 24 hours and 180 days were: Z2= 95.02 ± 10.72 and 63.50 ± 7.98; AB= 60.92 ± 5.43 and 39.43 ± 3.02; TB= 66.38 ± 7.38 and 41.05 ± 6.29; FB= 60.30 ± 8.42 and 44.61 ± 6.65. For bottom: Z2= 79.65 ± 9.67 and 52.36 ± 5.6; AB= 38.79 ± 6.46 and 30.16 ± 4.34; TB= 40.14 ± 7.79 and 31.55 ± 5.62; FB= 42.67 ± 5.94 and 33.69 ± 4.15. The AB, TB and FB groups obtained values significantly lower than the control, both at the top and at the bottom, at both moments. Conclusion: Aging in solvent reduced the microhardness for all composites, presenting no statistical difference between them. Only the control group obtained clinically acceptable results. The bulk fill resins are not able to be exposed to the humid environment, requiring an external coating.

Keywords: Dental restoration, permanent. Composite resins. Hardness tests.

How to cite: Henkes SMB, Henkes AJ, Arruda FZ, Fadanelli MA, Leitune VCB, Collares FM. In vitro microhardness evaluation of bulk fill resins after six months of water storage. J Clin Dent Res. 2018 Sept-Dec;15(3):38-46. DOI: https://doi.org/10.14436/2447-911x.15.3.038-046.oar

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