IADR Abstract Archives
Aging Effect on Push-Out Bond Strength of Six Resin Cements.
Objectives: To determine the push-out bond strength of six resin cements used to lute fiber posts, at 24-hours and 6-months aging.
Methods: Sixty human roots received endodontic treatment before fiber post luting (FRC Postec Plus size 0 and 1) using different resin cements: three self-adhesive resin cements (RelyX Unicem, RX; G-Cem, GC; NormoCem, NC), two universal resin cements (RelyX Universal, RU; G-Cem One, GO) and one self-etch resin cement used as control (Multilink Automix, MA). Resin cements were light-cured through the post for 60s (Spec3). After storage time, six slices were transversally obtained from each root, two corresponding to each root third: cervical, middle and apical. Push-out test was performed at a crosshead speed of 0,5 mm/min using a universal testing machine (Instron 3345). Type of failure was determined under steromicroscope (Olympus SZX7) and representative specimens were observed under SEM (Philips XL30 ESEM).Data were statistically analyzed by two-way ANOVA and Tukey tests.
Results: Mean and standard deviations are shown in Table 1. The root third did not influence on the bond strength at 24 hours nor at 6 months (p>0.05). All resins cements yielded similar bond strength values at 24 hours (p>0.05). At 6 months RX, GC, GO exhibited the highest strength, RU and MA intermediate values and NC the lowest values. After 6-month storage, bond strength significantly decreased for NC and MA. The adhesive failure was the most representative for all cements at both evaluation times except for MA, which showed adhesive and mixed failures equally at 24 hours.
Conclusions: Storage time had a detrimental effect on NC and MA bond strength. Immediate bond strength was similar for all cements. At 6 months, the lowest bond strength values were yielded by NC.
Methods: Sixty human roots received endodontic treatment before fiber post luting (FRC Postec Plus size 0 and 1) using different resin cements: three self-adhesive resin cements (RelyX Unicem, RX; G-Cem, GC; NormoCem, NC), two universal resin cements (RelyX Universal, RU; G-Cem One, GO) and one self-etch resin cement used as control (Multilink Automix, MA). Resin cements were light-cured through the post for 60s (Spec3). After storage time, six slices were transversally obtained from each root, two corresponding to each root third: cervical, middle and apical. Push-out test was performed at a crosshead speed of 0,5 mm/min using a universal testing machine (Instron 3345). Type of failure was determined under steromicroscope (Olympus SZX7) and representative specimens were observed under SEM (Philips XL30 ESEM).Data were statistically analyzed by two-way ANOVA and Tukey tests.
Results: Mean and standard deviations are shown in Table 1. The root third did not influence on the bond strength at 24 hours nor at 6 months (p>0.05). All resins cements yielded similar bond strength values at 24 hours (p>0.05). At 6 months RX, GC, GO exhibited the highest strength, RU and MA intermediate values and NC the lowest values. After 6-month storage, bond strength significantly decreased for NC and MA. The adhesive failure was the most representative for all cements at both evaluation times except for MA, which showed adhesive and mixed failures equally at 24 hours.
Conclusions: Storage time had a detrimental effect on NC and MA bond strength. Immediate bond strength was similar for all cements. At 6 months, the lowest bond strength values were yielded by NC.