Background: Primary Apical Periodontitis (AP) is caused by a microbial invasion of a root canal system which spread beyond the apex of the affected tooth. Most commonly used irrigant solution areNaOCl, CHX, EDTA, QMixTM and MTDA. Hence; we planned the present study to assess the interaction between the irrigants and characterize the by products formed in the associations between the most commonly used irrigants in endodontic practice through 1H NMR analyses. Materials & methods: We planned the present study to evaluate interactions between the most commonly used irrigants in endodontic practice.A total of ten experimental groups were formed on mixing the irrigants with each other along with five control groups. Equal volumes (2ml) of the root canal irrigants to be assessed were mixed in round bottom polysterene test tubes. The tubes were allowed to stand for 15 minutes to see if any interaction products are formed. These products were then centrifuged at 14000 rpm for 2.5 minutes. Spectra were taken with 400-MHz Varian NMR System at 250C, in perpetuated (dimethyl sulfoxide) d6-DMSO solvent. Results: In this study, the dried precipitates were dissolved in DMSO (Dimethyl Sulfoxide) which also plays the role of internal reference in NMR was subjected to proton NMR data acquisition. The characteristic FID (Free Induction Decay) patterns were recorded using 400 MHz NMR Bruker spectrometer. Conclusion: Therefore within the limitations of this study it can be said that the use of chlorohexidine should be done judiciously, and its use should be avoided in combination with: NaOCl, MTAD, and Combination of MTAD and QMix should also be avoided
Key words: Irrigants, NMR spectra, Endodontic therapy