Objectives: Compare the physical properties of Multilink Automix (MLA), RelyX Ultimate (RXUL) and the experimental cement (EXC) 1 and 24 hours after curing in the self-curing mode. Determine the discoloration with Safranin-T and coffee during the first 24 hours. After thermocycling the integrity of polymerized specimens should be judged.
Methods:
Thermocycling tests were done between 5°C to 55°C and 10’000 cycles with samples in the self-curing mode.
Flexural strength and modulus of elasticity were measured according to ISO-4049:2009 in the self-curing mode considering additionally the 1 hour values.
Discoloration tests were conducted in aqueous 0,01% Safranin-T and 3% coffee solutions in self-curing mode starting 1 hour after sample preparation and evaluated up to 24 hours in 37°C.
ANOVA and Tukey were used to determine differences (p<0.05).
Results:
The flexural strength and modulus in the self-curing mode (SC) after 1 hour compared to the 24 hour values are 31.1 percent lower for MLA, 39.4 percent for EXC and 83.5 percent for RXUL.
Cements |
1h-SC-Flexural-strength-(MPa) |
1h-SC-Modulus-of-elasticity-(MPa) |
24h-SC-Flexural-strength-(MPa) |
24h-SC-Modulus-of-elasticity-(MPa) |
MLA |
68.9±5.6 a |
2346±266a |
100.0±15.4a |
3928±327a |
EXC |
69.6±9.5a |
3204±115b |
114.9±14.1a |
5699±496b |
RXUL |
10.2±1.9b |
<200c |
61.8±3.9b |
3196±336a |
After 24 hours the order of discoloration with Safranin-T of materials cured in the self-curing mode is “EXC = MLA << RXUL” and with coffee “EXC = MLA < RXUL”.
Conclusions: After 1 hour the MLA and EXC are significantly stronger than RXUL. The discoloration with coffee and Safranin-T is the highest for RXUL. The experimental cement reaches significantly higher modulus of elasticity than the other two.