Infrared Spectroscopic Analysis of Tooth Structure and Dental Restorative Materials

Objectives: The aim of this study was to evaluate the structural analysis of various areas of tooth and differentiate them with different dental restorative materials. Methods: The extracted human teeth were obtained from tissue bank. The commercial materials included in this study were zinc oxide eugenol, zinc phosphate, glass ionomer cement (type I, type II) and resin-based composites. The materials were manipulated according to manufacturer's instructions. Fourier Transform Infrared Spectroscopy (FTIR) was used for all samples with resolution of 4cm^-1. The dental materials spectra were taken immediately after mixing and after duration of 10min, 60min, 24hrs, 72hrs, 96hrs and 120hrs. The samples were stored at 37°C during spectra collection time interval. Results: The tooth structure showed distinctive features of inorganic and organic components. Zinc oxide eugenol showed increase in intensity and appearance of new peaks with time. The spectra of zinc phosphate paste showed that after 60min the peaks were replaced by bands and these bands became broader after 96hrs. Glass ionomer cements exhibited no distinct peaks in the immediate spectrum while the peaks appeared after 10min that were replaced by bands after 60min, while the peak intensities increased after 72hrs. Resin-based composites showed degree of conversion after light curing, however, insignificant difference was observed with periodical time intervals. Conclusions: The spectroscopic analysis of these different dental materials provided in-situ setting behavior and understanding of their bonding, compatibility with tooth structure and change in relation with periodical time intervals.