Molecular signatures in infrared spectra of saliva in healthy, chronic and aggressive periodontitis

Abstract

The aim of the study was to employ IR spectroscopy to characterize saliva from healthy, chronic periodontitis, aggressive periodontitis and to determine specific spectral signatures that clearly demarcates healthy subjects, chronic periodontitis and aggressive periodontitis patients. 66 subjects (22 chronic periodontitis, 22 aggressive periodontitis and 22 healthy subjects) were recruited for the study. Unstimulated whole saliva sample was collected and lyophilization was done. 50 μl of salivary aliquots that was dispensed on a barium fluoride window was dried. IR spectra were recorded using a FTIR spectrometer. The spectral differences of saliva in three groups were analyzed using linear discriminant analysis. ANOVA test revealed that the mean difference of IR spectra between control and periodontitis groups was significant for wavelengths 1087 cm−1, 1240 cm-1 and 1652 cm−1 and 1740 cm−1. There was a significant increase in the mean IR spectra in aggressive periodontitis when compared to chronic periodontitis for wavelengths 1087 cm−1, 1240 cm−1 and 1652 cm−1 and 1740 cm−1, which corresponds to symmetric Po2- stretching vibrations of phosphodiester groups in DNA, asymmetric Po2- stretching vibrations of phosphodiester groups in DNA, amide I band and lipid ester respectively. Thus IR spectroscopy can be used as a non-invasive, rapid, reagent-free, cost effective method for the diagnosis of aggressive periodontitis and chronic periodontitis by analysing saliva sample.