Objectives: . To evaluate the degree of cure (%DC) of two self-adhesive resin cements, compared to a conventional dual-cure resin cement, in self- and dual-cure polymerization modes using differential scanning calorimetry (DSC).
Methods: Two commercial self-adhesive cements were tested: Maxcem (Kerr) and RelyX Unicem (3M ESPE). Panavia F2.0 (Kuraray Medical) was selected as a dual-cure resin based cement and used as control. Thermal analysis instrumentation (DSC) was used to measure the %DC of different cements. Cements were placed in pans with a transparent cover and polymerized within the DSC chamber. 10 specimens were dual-cured, immediately irradiated for 20s using a photo-polymerizing unit (600mW/cm2) and left undisturbed for 2hrs; 10 additional specimens were left to self-cure in the dark for 2hrs while in the DSC. Curing was performed at 35°C under a nitrogen atmosphere. Data were analyzed with two-way ANOVA and Tukey's post hoc test.
Results: %DC of all cements was higher when the dual-cure mode was used (p<0.05) vs self-cure polymerization. Overall, no significant difference was found between the self-adhesive cements and conventional dual-cured product Panavia F2.0 both within the dual-cure or self-cure modes.
| Dual-cure (%DC±SD) | Self-cure (%DC±SD) |
Maxcem | 58.85 ± 0.69a | 35.60 ± 1.27c |
RelyX Unicem Aplicap | 53.06 ± 1.38b | 31.68 ± 1.39d |
Panavia F2.0 | 58.61 ± 1.13a | 31.35 ± 1.82d |
Different superscript letters indicate significantly different values among test groups (p<0.05).
Conclusion: Self-adhesive cements showed %DC comparable to the conventional dual-curing cement. However, for each product tested, the %DC was significantly lower if allowed to self-cure only, as opposed to being exposed to light (dual-cure).