IADR Abstract Archives
Compositional Changes in Organic Matrix of Dentin by Post-Sequential Irrigation
Objectives: Preparation of dentin prior to treatment involves irrigating the tissue with sequential use of proteolytic (sodium hypochlorite) and chelating agent (ethylenediaminetetraacetic acid). These chemicals affect the dentin matrix composed of organic collagen fibers and inorganic components, and alter the dentin ultrastructure and its properties. The aim is to analyze the compositional changes within dentin after treatment with saline, NaOCl, and EDTA, using FTIR, polarized light, and electron diffraction spectroscopies.
Methods: Dentin blocks (n = 24, 4mm x 3mm x 2mm) were obtained from freshly extracted third molars and divided into 4 groups based on irrigants used: saline (group 1), NaOCl (15min), group 2, NaOCl-EDTA (15-2-min), group ,3 and NaOCl-EDTA-NaOCl (15-2-2-min), group 4. Half of the specimen from each group were demineralized, stained with picrosirius, and observed under polarized light microscope (PLM). The mineralized samples were analyzed using FTIR and EDS spectroscopy. Atomic-weight-% of carbon and nitrogen obtained were statistically analyzed using one-way-ANOVA (P=0.05).
Results: Under PLM, the network of organized collagen fibers is seen (group 1). There is a change in organization of these fibers in groups 2 and 3. Group 3 shows thinning of fibers. The intensity of the pixels was higher in group 1 and 4 with presence of red, blue, and green channels. Groups 2 and 3 had lower peak levels, with diminished blue channel in group 3, suggesting loss of components. This was confirmed using FTIR, where group 2 and 4, have no amide III peak. Group 2 had significantly lesser C and N percentage compared with group 1.
Conclusions: Different changes take place in the organic matrix of the dentin with the sequential use of saline, NaOCl, and EDTA.
Methods: Dentin blocks (n = 24, 4mm x 3mm x 2mm) were obtained from freshly extracted third molars and divided into 4 groups based on irrigants used: saline (group 1), NaOCl (15min), group 2, NaOCl-EDTA (15-2-min), group ,3 and NaOCl-EDTA-NaOCl (15-2-2-min), group 4. Half of the specimen from each group were demineralized, stained with picrosirius, and observed under polarized light microscope (PLM). The mineralized samples were analyzed using FTIR and EDS spectroscopy. Atomic-weight-% of carbon and nitrogen obtained were statistically analyzed using one-way-ANOVA (P=0.05).
Results: Under PLM, the network of organized collagen fibers is seen (group 1). There is a change in organization of these fibers in groups 2 and 3. Group 3 shows thinning of fibers. The intensity of the pixels was higher in group 1 and 4 with presence of red, blue, and green channels. Groups 2 and 3 had lower peak levels, with diminished blue channel in group 3, suggesting loss of components. This was confirmed using FTIR, where group 2 and 4, have no amide III peak. Group 2 had significantly lesser C and N percentage compared with group 1.
Conclusions: Different changes take place in the organic matrix of the dentin with the sequential use of saline, NaOCl, and EDTA.