FTIR Spectroscopy Revealing the Effects of Laser and Ionizing Radiation on Biological Hard Tissues

Effect of 2.94 µm Er: YAG laser on the chemical composition of hard tissues

“…Enamel has just 1.5% of organic constituents (Antunes, de Rossi, & Zezell, 2006; Iijima, Fan, Bromley, Sun, & Moradian‐Oldak, ). Our results relating to dentin agree with previous studies (Choeysuppaket, Pokaipisit, & Limsuwan, ; Soares, Resende, Brugnera, Zanin, & Martin, 2007), and disagree with some previous findings (Antunes et al, ; Bakry et al, ; Soares et al, ; Zezell et al, ). The difference might be due to different methodologies (Sasaki et al, ).…”

“…The literature demonstrates that the laser radiation can induce collagen denaturation and water evaporation, which can be observed as a decrease in the infrared bands of amide I, II, and III in the analysis under FTIR spectroscopy. Related to the inorganic matter, the literature shows that the evaporation of carbonate can occur due to laser radiation, which shown as a decrease in the carbonate bands proportional to the phosphate in the irradiated sample when analyzed by the FTIR spectroscopy (Zezell, Benetti, Veloso, Castroa, & Anab, ). Furthermore, the carbonization effect of the laser energy on the biological hard tissues may be seen as changes in the band positions, disappearance or appearance of new infrared bands (Zezell et al, ).…”

“…Related to the inorganic matter, the literature shows that the evaporation of carbonate can occur due to laser radiation, which shown as a decrease in the carbonate bands proportional to the phosphate in the irradiated sample when analyzed by the FTIR spectroscopy (Zezell, Benetti, Veloso, Castroa, & Anab, ). Furthermore, the carbonization effect of the laser energy on the biological hard tissues may be seen as changes in the band positions, disappearance or appearance of new infrared bands (Zezell et al, ). With a temperature rise, the elimination of carbonate happens progressively and was a maximum value between 400 and 800°C (Corrêa‐Afonso, Bachmann, de Almeida, Corona, & Borsatto, ).…”

“…In the spectra in Figures it is possible to see that all the main infrared bands of hard tissues are maintained, which suggests that the Er‐YAG laser irradiation used did not induce the complete degradation of any component of the hard tissues. Therefore, it is possible to infer that the Er‐YAG laser radiation did not raise the surface temperature more than 700°C, which is the temperature that causes degradation of organic matter (Zezell et al, ). The low temperature rise might be attributed to the moist environment.…”

ATR-FTIR Assessment of the Biochemical Composition and Micro Hardness of the Hard Tissues of Oral Cavity Submitted to Gamma Irradiation

“…The infrared spectra of enamel region are showed in Figure 15 , related to asymmetric axial deformation of C-H bond from methylene group of hydrocarbon chain; at 1.731 cm -1 , related to axial deformation of C-O-O-bonds (peroxide group); at 1.465 cm -1 related to angular deformation from amide group (amide III) 46; at 1.165 cm -1 , corresponds to asymmetric axial deformation of C-O-C bonds (ether group); at 1.034 cm -1 and 873 cm -1 related to infrared absorption of PO43-(phosphate group) and at 715 cm -1 corresponding to out-of-plane angular deformation of hydroxyl group linked by hydrogen bonds. This analysis suggests sample is formed by proteins, an inorganic region and water that is according to dental enamel composition, presented in the literature [41][42][43][44] specifically 97% of poly hydroxy apatite, 1% of protein, being ameloblastine, enamelin, amelogenin and 2% of water [45][46][47]. Irradiated samples (E26_1708 and E18_1708) showed almost the same absorption bands, however, the band at 3.425 cm -1 disappeared, suggesting water removal and a band at 877 cm -1 is observed, suggesting some changes in poly hydroxy apatite inorganic region (Figure 16) shows irradiated and non-irradiated root dentine spectra.…”