The impact of irrigating solutions on root canal dentin

The goal of the study. Comparison of the removal process quality when the smear layer inorganic part is removed from the root dentin of the tooth using irrigation solutions of citric and ethylenediaminetetraacetic acid (EDTA). Material and methods. Forty root canals of the teeth were divided into two groups of 20 canals each and processed to size 30—35 in the apical apex area, with a taper of 0.4—0.6. In the first group, the root canal irrigation protocol included the use of 3.25% sodium hypochlorite (NaOCl) solution and 40% citric acid solution, in the second group — 3.25% NaOCl solution and 17% EDTA solution. The study of 74 micrographs within samples of the middle and apical thirds of the root canals in the first and second groups was performed on a scanning electron microscope and assessed on a five-point scale to find the degree of root dentin cleaning. Results. When comparing the two irrigation protocols, it has been revealed that there are differences in the degree of cleaning and the effect of solutions on dentin for the apical and middle thirds of the root canal. The factors including lower percentage of dentinal tubules covered with a smear layer in the apical third and the percentage distribution of open dentinal tubules in the middle third confirm a better efficiency of EDTA. A high percentage of dentin erosions (55%) was found in samples processed with citric acid. In addition, crystals found on the dentin surface were revealed only in the first group. Calcospherites were noticed in half of the root canals of the second group. Conclusion. That study confirms the effect of 40% citric acid and 17% EDTA on the smear layer formed in root dentin by means of instrumentation, as well as their difference in cleaning efficiency and effect on root dentin.