FTIR characterization of the setting reaction of biodentine™

Objective. To provide insight of the setting reactions of Biodentine (TM), a hydraulic calcium silicate cement, based upon observations using Fourier Transform Infra-Red (FTIR) spectroscopy. Methods. FTIR spectra of components before and during the setting reaction were taken using the attenuated total reflectance (ATR) technique. Measurements over wavelengths 600-4000 cm(-1) were taken at regular intervals for two days. Results. FTIR spectrum of Biodentine (TM) powder revealed a number of peaks from 650 to 1100 cm(-1) and a plateau from 1400 to 1500 cm(-1), indicative of Si-O and CO3-bonding, while the mixing fluid exhibited water peaks. Results following mixing displayed three distinct regimes; (i) incubation phase, during the first 35 min, when minimal change occurred, (ii) rapid transitory stage, between 35 and 90 min, when major changes occurred, and (iii) slow sustained reaction stage for remaining 45 h. Incubation appears to be associated with the presence of CO3-peaks. The transition region indicates formation of CaOH and Jennite OH-peaks, anticipated intermediate reaction phases. At 90 min, the end of second stage, CaOH and Jennite are replaced by a dominant Portlandite (Ca(OH)(2))-peak and minor presence of Tobermorite, another anticipated intermediate phase, and water reduction. During the following 45 h Portlandite and Tobermorite decline while the water peak increases. Significance. FTIR can be used to follow the chemical reactions in dental cements and provides insight into the relatively slow setting reactions of hydraulic calcium silicate cements. (C) 2018 Published by Elsevier Inc. on behalf of The Academy of Dental Materials.