Time-dependent decalcifying effects of endodontic irrigants with antibacterial properties

The aim of this study was to investigate the extent of calcium ion (Ca(2+)) removal on root dentin after treatment with 1.25% NaOCl, 2.5% NaOCl, 5.25% NaOCl, 2% chlorhexidine (CHX), 2% iodine potassium iodide (IKI), and MTAD in 3 immersion time periods. Extracted human mandibular premolars were bisected longitudinally, and the root halves (n = 70) were isolated with nail varnish, leaving the root canal exposed. The specimens were immersed in the test solutions, during which the amount of Ca(2+) release into the solutions was determined at 5, 10, and 15 minutes by flame photometry. The decalcifying effect of 5%, 2.5%, and 1.25% NaOCl and 2% IKI significantly increased within time (P < .05), with 5% NaOCl extracting the greatest amount of Ca(2+) at all treatment times. For 2% CHX and distilled water, a significant increase in the amount of Ca(2+) extraction from root dentin was only evident at 10 minutes (P < .05) and did not change at 15-minute readings. Between the 5- to 10-minute and 10- to 15-minute intervals, the greatest amount of increase in the rate of Ca(2+) extraction from root dentin was observed in the 2.5% NaOCl group. At 15 minutes, 2% CHX and distilled water showed the least amount of change. Among the test solutions, MTAD extracted the least amount of Ca(2+) at 5 minutes.