Effect of Medicaments Used in Endodontic Regeneration Technique on the Chemical Structure of Human Immature Radicular Dentin: An In Vitro Study

Abstract Introduction The aim of this study was to investigate the effect of 3 intracanal medicaments used in pulp regeneration on the chemical structure of radicular dentin. Methods Human immature radicular dentin specimens were exposed to triple antibiotic paste (tripaste), double antibiotic paste (bipaste), calcium hydroxide [(Ca(OH)2 ] paste, or deionized water (control) for 1, 2, or 4 weeks. After each time point, specimens were examined with attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy to analyze the relative loss of organic and inorganic components by using phosphate/amide I ratios. Data were analyzed by using analysis of variance followed by post hoc comparisons. Results Phosphate/amide ratios were significantly different between the 4 groups at all time points ( P < .0001): Ca(OH)2 -treated dentin > untreated control dentin > bipaste-treated dentin > tripaste-treated dentin. For bipaste groups, 4-week treated dentin had significantly lower phosphate/amide I ratios than 1- and 2-week treated dentin ( P < .05); however, phosphate/amide I ratios of 1- and 2-week treated dentin did not have a significant difference. For tripaste groups, 4-week treated dentin had a significantly higher phosphate/amide I ratio than 1- and 2-week treated dentin ( P < .001), and phosphate/amide I ratio of 1-week treated dentin was significantly higher than that of 2-week treated dentin ( P = .04). No significant time effect for Ca(OH)2 -treated dentin or untreated control dentin was found ( P > .05). Conclusions The results suggested a superficial collagen degradation or demineralization of radicular dentin caused by Ca(OH)2 or antibiotic pastes, respectively, after 1, 2, or 4 weeks of exposure.