Original scientific paper
Fourier-transform infrared spectroscopic method for assessing sensitivity of light-curable dental restorative composites to ambient light – a pilot study
Lucija Gotovac
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Stella Horvat
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Vlatko Pandurić
; Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Zrinka Tarle
; Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Matej Par
; Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
*
* Corresponding author.
Abstract
Aim: To investigate whether Fourier transform infrared spectroscopy (FTIR) can be used to identify the point at which polymerization begins when dental restorative composites are exposed to ambient light.
Materials and methods: An FTIR spectrometer with an attenuated total reflectance (ATR) diamond accessory and a mercury-cadmium-telluride detector was used to evaluate real-time changes in the degree of conversion (DC) at a fast data collection rate (2 spectra/s). The 0.1 and 0.2 mm thick samples of three commercial composites (OmniChroma, Tetric PowerFill, and Filtek One Bulk Fill) were irradiated with white light simulating dental operating light (temperature of 4,000 K and illuminance of 8,000 lux, according to the recommendations of ISO 4049). The DC data were plotted as a function of time and the first derivative was calculated. The first time point with a non-zero value of the first derivative was considered to indicate the start of the polymerization reaction.
Results: Statistically significant differences in time of onset of polymerization were observed between the materials at both layer thicknesses (p<0.001) with the following material ranking: OmniChroma > Tetric PowerFill > Filtek One Bulk Fill. The highest mean values were measured for OmniChroma (161.75 s / 193.0 s) while the lowest mean values were observed for Filtek One Bulk Fill (76.0 s / 96.75 s) for 0.1 mm and 0.2 mm thick layers, respectively. Statistically significant effects of layer thickness were observed for OmniChroma (p=0.002) and Filtek One Bulk Fill (p<0.001), while Tetric PowerFill showed no significant effect of layer thickness (p=0.350).
Conclusions: High-speed ATR-FTIR spectrometry can be used to detect early signs of the onset of polymerization of dental restorative composites with high sensitivity and reproducibility.
Keywords
dental composites; spectroscopy
Hrčak ID:
318611
URI
Publication date:
25.6.2024.
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