LAUSR

Abstract Background One of the most important yet unresolved tasks facing therapeutic dentistry is the problem of efficient personalised diagnostics of pathological processes in the dentine tissues of human teeth. In this regard, dentine fluid is an ideal screening candidate, which acts as an important factor in the development of dentine caries. However, the serious difficulty and practical impossibility of dentine fluid sampling in vivo is the main obstacle to its use in advancing a new line of diagnostics. Extracting gingival crevicular fluid for diagnosing is a much simpler approach. Therefore, we sought to establish the molecular composition and protein conformation of blood, dentine fluid, and gingival fluid during the development of dentine caries using synchrotron FTIR investigations. Methods Ten participants aged 22–28 participated in the study. Each participant had teeth with lesion foci related to primary and secondary enamel surface caries (tooth decay). Three biological fluid samples were obtained for each participant: dentine fluid, gingival crevicular fluid, and blood. The molecular composition of the samples was investigated using FTIR synchrotron spectroscopy technique. Findings Based on the mathematical simulation of absorption band Amide I in the FTIR spectra of the samples, it was found that the development of pathological processes of the carious type in dentine tissue affects the molecular composition of the biological fluids coming in contact with hard dental tissue. In addition, for the first time, we observed an increased content of thiocyanates and complex esters as well as the presence of anti-inflammatory cytokines, and their interaction with the secondary protein structure in the dentine fluid and gingival crevicular fluid for people with pathological carious processes in the dental tissues. Conclusion The detected features in the FTIR spectra of biological fluids within the oral cavity in combination with the well-known in literature spectral markers of the development of carious process in dentine prove to be significant, reliable signatures of pathology that can relatively easily detected in the analysis of gingival fluid.