Proof-of-concept study to establish an insitu method to determine the nature and depth of collagen changes in dentine using Fourier Transform Infra-Red spectroscopy after sodium hypochlorite irrigation.

Abstract

To establish a method using Fourier Transform Infra-Red spectroscopy (FTIR) to characterize the nature and depth of changes in dentinal collagen following exposure to sodium hypochlorite (NaOCl) during root canal irrigation in an ex vivo model. Fourier Transform Infra-Red spectroscopy was used to assess the changes in dentinal collagen when the root canal was exposed to NaOCl. The changes in dentinal collagen caused by NaOCl irrigation of root canals in transverse sections of roots, at 0.5mm from the canal wall and 0.5mm from the external root surface, were assessed by FTIR. The data were analysed using paired t-test with 5% significance level. Fourier Transform Infra-Red spectroscopy confirmed that NaOCl exposure caused alterations in the chemistry and structure of collagen in dentine. FTIR spectra obtained from dentine surfaces and dentine adjacent to root canals exposed to NaOCl, all consistently showed degradation and conformational change of the collagen structure. FTIR data from the exvivo model showed that the depth of effect of NaOCl extended to at least 0.5mm from the canal wall. In extracted human teeth, NaOCl caused changes in dentinal collagen that were measurable by FTIR. In an ex vivo model, the depth of effect into dentine extended at least 0.5mm from the canal wall.