This study evaluated the effect of the activa tion mode on flexural strength and elasticity modulus of four dual cure resin-based cements. Methods: Two self-adhesive resin cements (Clearfil SA Cement (CSA) and RelyX U100 (U)) and two conventional resin cements (Clearfil Esthetic Cement (CE) and...

This study evaluated the effect of the activa tion mode on flexural strength and elasticity modulus of four dual cure resin-based cements. Methods: Two self-adhesive resin cements (Clearfil SA Cement (CSA) and RelyX U100 (U)) and two conventional resin cements (Clearfil Esthetic Cement (CE) and RelyX ARC (ARC)) were used to produce a total of 45 bar specimens (7x2x2 mm) using three different activation modes (n=15): Direct light-cure (D), Indirect light-cure using a 2mm composite resin barrier (I) and Self-cure (S). Three-point flexural tests were performed after 24 hours water storage at 37 degrees C, using a universal testing machine (Instron) at a cross-speed of 0.5 mm/min until fracture. Flexural strength (MPa) and elasticity modulus values were subjected to ANOVA and Tukey's Test (alpha=0.05). Results: Data revealed that light polymerized groups presented statistically higher flexural strength (CSA/D=113.63 +/- 19.65; CSA/I=80.66 +/- 23.74; U/D=101.33 +/- 9.8; U/I=94.96 +/- 36.9; CE/D=219.08 +/- 39.94; CE/I=226.42 +/- 34.59; ARC/D=150.03 +/- 26.15; ARC/I=111.78 +/- 14.28) and also elasticity modulus values (CSA/D = 2.9 +/- 0.6; CSA/I = 1.5 +/- 0.4; U/D = 2.9 +/- 0.5; U/I = 2.6 +/- 1.4; CE/D = 6.5 +/- 1.3; CE/I = 5.8 +/- 1.0; ARC/D = 4.2 +/- 0.93; ARC/I = 2.5 +/- 0.5) compared to self-cured groups (flexural strength: CSA/S=65.81 +/- 21.84; U/S=53.62 +/- 28.73; CE/S=129.02 +/- 51.67; ARC/S=77.98 +/- 19.61 and elasticity modulus: CSA/S = 1.4 +/- 0.5; U/S = 1.2 +/- 0.7; CE/S = 2.2 +/- 1.5; ARC/S = 1.0 +/- 0.5). The usage of a composite resin barrier only affected the mechanical properties of ARC and CSA. Conventional resin cements presented higher flexural strength values than the self-adhesive cements. CE presented the highest values compared to all other cements. No statistical difference was observed between self-adhesive cements. Conclusion: Light-curing of resin luting cements produced higher flexural strength for all tested materials. Similar mechanical behavior was observed for the tested self-adhesive cements

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

307540/2009-0

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