Featured article

Degree of conversion of Filtek Silorane Adhesive System and Clearfil SE Bond within the hybrid and adhesive layer: An in situ Raman analysis.

Chiara O. Navarra, Milena Cadenaro, Steven R. Armstrong, Julie Jessop, Francesca Antoniolli, Valter Sergo, Roberto Di Lenarda and Lorenzo Breschi

Dental Materials 2009:25(9):1178-1185

Abstract

Objectives: To examine the degree of conversion (DC) of the adhesive interfaces created by Filtek Silorane Adhesive and Clearfil SE Bond using micro-Raman spectroscopy.

Methods: The adhesives were applied on human dentin in accordance with manufacturer's instructions. Specimens were cut to expose the bonded interfaces to the micro-Raman beam (Ranishaw InVia; laser wl 785 nm). Raman spectra were collected along the dentin/self-etching primer/adhesive interface at 1 μm intervals. The relative intensities of bands associated with mineral (P–O functional group at 960 cm−1) and adhesive (C–C–O group at 605 cm−1) components within the bonded interface were used to detect monomer penetration into the dentin matrix and to calculate the degree of conversion (Cdouble bond; length as m-dashC at 1640 cm−1 as reaction peak, C–C–O at 605 cm−1 as reference peak). Data were statistically analyzed with two-way ANOVA.

Results: DC of Filtek Silorane Adhesive was 69 ± 7% in the adhesive layer, increasing (p<.05) to 93 ± 5% in the primer and 92 ± 9% in the hybrid layer. Clearfil SE Bond showed a DC of 83 ± 3% in the hybrid and 85 ± 3% in the adhesive layer. Thus, Filtek Silorane Adhesive showed a higher DC than Clearfil SE Bond in the hybrid layer (p<.05), but a lower DC in the adhesive (p<.05).

Significance: As high DC is a fundamental pre-requisite for the stability of the bond over time, this study supports the hypothesis that optimal stability of Filtek Silorane Adhesive can be obtained. However, further research is needed to investigate the mechanical properties of the hybrid layer created by Filtek Silorane Adhesive and its long-term stability.