Comparison of the Degree of Conversion of Two Resin Cements When using a Fiber Post

Tooth-colored non-metal posts are adhered to the canal walls with the use of resin cements and dentin adhesives. Degree of conversion of these cements is especially important to ensure the durability of the restoration. The present study aimed at evaluating the degree of conversion (DC%) of self-cure and dual-cure resin cements at different depths and time points when using a DT. Light Post.

In this experimental study, metal molds with 5 and 10 mm heights and internal diameter of 0.8 mm were used. Posts were vertically placed in the center of molds. Spectrum of absorption of the dual cure cement was measured before curing using Fourier transform infrared spectroscopy device. The uncured samples were then removed from the device and placed beneath the molds. After light irradiation, samples were transferred again to the FTIR device and their spectrum of absorption was measured. DC% was calculated using the relevant formula. For self-cure cements, spectrum of absorption was measured at 0, 2, 5, 10 and 15 minutes by the FTIR. Results were statistically analyzed using SPSS software.

Self-cure cement had a DC of 5% at 0, 2, 5 and 10 minutes and a DC of 20% at 15 minutes. DC of the dual-cure cement was 44%, 15% and 8% at 0, 5 and 10 mm depths, respectively. Two-way ANOVA and Tukey’s Post Hoc test (HSD) revealed that in the dual-cure cement the DC at 5 and 10 mm depths was significantly different (P<0.05). DC was 20% at 15 minutes which was the highest.

DC% of the dual-cure cement was higher than that of the self-cure cement which is attributed to the optimal characteristics of the dual-cure cement and also the ability of fiber post to pass light.