Objectives: This study evaluated the initial (1min.) and delayed (24hr) shear bond strength (SBS) of three self-adhesive resin cements to e-max Press. The self-adhesive resin cements tested were SpeedCEM(S) (IvoclarVivadent), RelyX™ Unicem(U) (3M ESPE) and Maxcem Elite™(M) (Kerr).
Methods: Thirty-six freshly prepared human molars were used. The teeth were sectioned longitudinally and mounted in acrylic with the buccal surface exposed. The exposed surfaces were coarsely ground flat then finished with 600 grit sanding paper (n=12). The e.max Press rods (2.5mm diameter) were cleaned with 600 grit silicon carbide paper, treated with IPS Ceramic Etching-gel for 20 seconds and then with Monobond Plus for 1 minute. Ceramic specimens were coated with cement, seated on the prepared dentin surface, excess removed and then light-cured for 20s on each side. Twenty-four hour specimens were stored at 37°C and 100% humidity before testing. SBS was measured using a universal testing machine at a crosshead speed of 1 mm/min. Bond strength values were calculated in MPa and subjected to statistical analysis (ANOVA, p<0.05).
Results: Groups with same letter are not statistically different (p>0.5)
Cement | Condition | Mean(SD) |
(S)SpeedCEM | Light Cure / Immediate | 15.7 (3.3)a |
(S)SpeedCEM | Light Cure / 24hr | 17.7 (3.1)a |
(U)Relyx Unicem | Light Cure / Immediate | 8.1 (2.6)c |
(U)Relyx Unicem | Light Cure / 24 hr | 11.6 (2.6) |
(M)Maxcem Elite | Light Cure / Immediate | 6.2 (2.7)bc |
(M)Maxcem Elite | Light Cure / 24hr | 5.9 (2.5)bc |
Conclusions: There were no statistical differences for self-adhesive cements S and M at 1 minute and 24 hrs. Cement U was statistically different (p<0.05) to cement S but not to cement M. Cement S values were statistically higher than the other two (p<0.05). The performance of each cement greatly depends upon the setting reaction, the substrate preparation and the curing mode. This study was partially funded by Ivoclar Vivadent.