Evaluation of the flexural strength of dual-cure composite resin cements

The aim of this study was to evaluate of flexural strength of some adhesive resin cements. Three dual-cure composite resin cements (Nexus 3; Variolink II, Panavia F) were prepared. The manufacturer's mixing directions for the cements were followed. Adhesive resin cement was mixed, placed in the rectangular portion of the mold. Fifteen specimens were prepared for each cements. The cements were light-activated with light lamp for 40 s on both and top and bottom surfaces. The each cement specimens were divided into three groups according to time of storage and stored in distilled water for 24 h, 15, and 30 days. Total 45 specimens were stored at 37 degrees C (98.6 0F) in distilled water for 24 h, 15, and 30 days prior to tests. The flexural strength was tested wth a universal testing machine at a crosshead speed of 0.5 mm/min (0.02 in.) The maximum load was recorded as MPa. The results were analyzed by Analysis of Variance and Duncan test. The Panavia F resin cements content Bisphenol A was showed the highest flexural strength (80.80 MPa) (11.71 ksi) for 24 h. The lowest flexural strength was observed in Nexus 3 (51.00 MPa) (7.39 ksi). It was found significant interaction of material and time (p < 0.05). The types of cement and time of storage was statistically significant on the flexural strengths (p < 0.001). (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.