Effect of medicaments used in endodontic regeneration technique on the chemical structure of human immature radicular dentin: an in vitro study.

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.