Degree of conversion and depth of cure of Ivocerin containing photo-polymerized resin luting cement in comparison to conventional luting agents

Objective: To evaluate the degree of conversion (DC) and depth (extent) of cure of four resin cements (Variolink E, Calibra, NX3 and Variolink N) using Fourier transform infrared (FTIR) and Vickers Micro hardness (MH).

Methods: Ten disks (1mmx2mm) of each resin cement were light cured through a ceramic disk for 40 seconds prior to assessment. The ATR spectra of the uncured resin were collected in absorbance mode from 16 scans at 4 wave number resolutions. Degree of conversion was calculated by estimating the changes in peak height ratio of the absorbance intensities of aliphatic C=C peak at 1638 cm-1 and that of an internal standard peak of aromatic C=C at 1608 cm-1 during polymerization. For Vickers microhardness testing 10 disks of each cement specimen was exposed to 100 grams of load for 15 seconds. Three indentations were made 0.5mm apart and an average Vickers micro-hardness (MH) for each specimen. Two way ANOVA and multiple comparison tests were performed to assess data.

Results: The highest degree of conversion by peak area was shown by Variolink-Esthetic [light-cure (87.18±2.90%)]; however the lowest was observed in samples of Variolink-N [Dual cure (44.55±4.33%)]. Similarly, Variolink-Esthetic and NX3 cement showed significantly higher MH as compared to other groups.

Conclusion: Ivocerin containing Variolink–E cement showed high degree of conversion and extent of polymerization when compared to conventional light and dual cure luting cements.