FT-Raman spectroscopy was used to study the human and bovine dentin and their interactions with adhesive systems. Ten human (H) molars and ten bovine (B) teeth were prepared exposing the dentin and then each specimen was divided into two parts. The resulted forty dentin segments were treated either with the total-etch one bottle adhesive (Prime & Bond 2.1, PB) or with the single-step self-etching adhesive (Xeno III, X) and divided into four groups: HPB (control), HX, BPB, and BX. Each group was analyzed by FT-Raman spectroscopy before and after the adhesive treatment. Six regions of the Raman spectrum were analyzed and the integrated areas of organic and inorganic peaks were calculated. Bovine untreated specimens showed higher peak area ofPO4 3−ν2  content than in human specimens. Human untreated specimens had higher peak areas ofPO4 3−ν4andCO3 2−ν1  contents than in bovine specimens. The peak areas of amide III,CH2, and amide I contents were higher in human than in bovine specimens (before treatments). Treated dentin showed no significant statistical differences between the adhesives for both inorganic and organic contents considering the same substrate. However, the differences found between human and bovine specimens after adhesives application show a reduced accuracy of these substrates as a substitute to the human specimens.

EPR and fluorescence spectroscopy were used to evaluate the degradation of crude oils of different origins that were submitted to photochemical weathering under tropical conditions. The EPR spectra obtained showed signals of the paramagnetic species: the vanadylVO2+ion and organic free radicals. A decrease in linewidth of free radical signals was observed for both oils irradiated for 100 hours with sunlight of 350 W/m2. The reduction in the linewidth of the free radical of 9.8% in Arabian oil and 18.5% in Colombian oil, as well as the decrease in radical numbers, indicated photochemical degradation, especially in Colombian oil. The linewidth narrowing corresponding to free radicals in the irradiated oils occurred due to the rearrangement among radicals and aromatic carbon consumption. The irradiated oils showed a reduction in the relative intensity of fluorescence of the aromatics with high molecular mass, polar aromatics, and asphaltene. The fluorescent fraction was reduced by 61% in Arabian oil and 72% in Colombian oil, corresponding to photochemical degradation of crude oil aromatic compounds.