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Objective To investigate the effect of surface sealant coating on flexural strength of four provisional resin materials used for fixed partial prosthesis.
Materials and Methods The total of one hundred and twenty-eight bar-shaped specimens (25 mm ×2 mm× 2 mm) were fabricated from four provisional restorative materials according to manufacturer’s instruction: methacrylate resin (Unifast Trad) and bis-acryl resins (Protemp 4, Luxatemp Fluorescence and Integrity). The prepared specimens were wet polished with 320-grit silicon carbide abrasive paper. The specimens of each material were then randomly assigned into 2 groups; group 1: non-sealant group (n=16) as a control group and group 2: sealant group (n=16). For group 1, the specimens were immersed in 37oC distilled water for 24 hours. For group 2, the specimens were sandblasted with 50 micron-aluminium oxide, rinsed with water and dried. Then the surface sealant agent (Optiglaze color) was applied on the specimens’ surface and the specimens were immersed in 37oC distilled water for 24 hours. After both groups were stored in distilled water for 24 hours, the three-point flexural strength test by a universal testing machine (EZ-S, SHIMADZU, Japan) with a cross-head speed of 1±0.3 mm/min was performed and the data were analyzed by using a two-way analysis of variance.
Results In non-sealant group, the mean flexural strength of Unifast Trad, Protemp 4, Luxatemp fluorescence and Integrity were 63.45, 66.94, 71.64 and 76.18 MPa, respectively. Flexural strength of all bis-acryl resins was higher than methacrylate resins except Protemp 4, which was not statistically different from GC Unifast Trad (p>0.05). In sealant group, the mean flexural strength of Unifast Trad, Protemp 4, Luxatemp fluorescence and Integrity with surface sealant agent were 57.87, 72.51, 71.86 and 62.19 MPa, respectively. The mean flexural strength of Integrity and Luxatemp fluorescence in non-sealant group were statistically significant higher than Protemp 4 and GC Unifast (p<0.05). The mean flexural strength of Integrity and GC Unifast Trad in sealant group were statistically lower than non-sealant group (p<0.05). The mean flexural strength of Protemp 4 in sealant group were statistically higher than non-sealant group (p<0.05). The mean flexural strength of Luxatemp fluorescence in sealant group were not statistically difference from non-sealant group (p>0.05).
Conclusion The application of surface sealant did not increase the flexural strength of GC Unifast Trad, Integrity and Luxatemp fluorescence but it could improve the flexural strength of Protemp 4.
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