Raman spectroscopy analysis of coro- nary dentin of vital and endodonti- cally treated teeth

Purpose: The present study aimed to investigate the properties of coronary dentin of vital and endodontically treated human teeth using Raman Spectroscopy.Material&Methods: The samples used were taken from coronary dentin of intact extracted human teeth, ul-trasonically cleaned and stored in a 0.2% thymol solution at 4 degrees Celsius for up to 3 months. They were divided into two groups - "vital dentin" and "endodontically treated dentin" samples. Each sample was crossed-sec-tioned, embedded in resin, polished and subjected to Ra-man spectroscopy with a Horiba Jobin-Yvon T64000 tri-ple-grating spectrometer, using a CdHe laser with 4 im di-ameter of the laser spot and 2.5mW of power on the exam-ined surface. The resultant diagrams were analyzed using the software package Origin 9.6 andunderwent baseline correction and normalization. A comparison between the two studied groups was made.Results: The results from the "vital dentin" group showed a well-expressed crystalline structure, with clear peaks corresponding to pure and b-carbonated hydroxya-patite. The results of the "endodontically treated dentin" group showed the presence of new chemical compounds - octacalcium phosphate, tricalcium phosphate and dicalcium phosphate dihydrate, as well as increased inten-sity of the-carbonated hydroxyapatite peaks. Conclusions: The presence of mineral substances with low calcium content could contribute to a decrease in dentin toughness, which in turn can lessen the mechani-cal properties of endodontically treated teeth. Raman spectroscopy can be a useful tool in the detection of these dentin components.