sodium-hypochlorite and hydroxide-ion

Intracanal mineral trioxide aggregate (MTA) may provide an alternative to calcium hydroxide in the treatment of external inflammatory root resorption. This in vitro study using human matched pairs of teeth compared white ProRoot MTA (WMTA; (Dentsply Tulsa Dental Specialties, Tulsa, OK) and an alternative material with purportedly improved handling properties, EndoSequence Root Repair Material (ES; Brasseler USA, Savannah, GA), by measuring pH in simulated root surface resorptive defects after intracanal placement. The null hypothesis tested was that there is no difference between WMTA and ES.. Bilaterally matched pairs (n = 24) of extracted, human, single-rooted teeth were instrumented to apical size 50/.06, and root surface cavities were prepared at 5 mm and 2 mm from the apex. Root canals of experimental matched pairs (n = 20) were filled with WMTA or ES; control pairs (n = 4) were filled with calcium hydroxide (positive control [POS]) or saline (negative control [NEG]). Teeth were sealed coronally and apically and immersed in saline. The pH in root surface cavities was measured at 20 minutes, 3 hours, 24 hours, 1 week, 2 weeks, 3 weeks, and 4 weeks.. The pH at 5 mm when compared with the 2-mm level was significantly higher for the WMTA, ES, and POS groups (P < .05, paired t tests); therefore, each level was analyzed separately. At both the 2-mm and 5-mm levels, significant pH changes occurred over time in the WMTA, ES (both P < .0001, repeated-measures analysis of variance), and POS (P < .0001, Friedman test) groups and not in the NEG group (mean pH = 7.32 ± 0.04, P > .05). There were no differences between WMTA and ES at 20 minutes and 3 hours at both levels or at 24 hours at 5mm. The pH of WMTA was higher than ES by 24 hours at the 2-mm level (8.79 vs 8.56, P < .05, paired t test) and after 1 week at the 5-mm level (8.91 vs 8.05, P < .0001) and was thereafter always significantly higher in WMTA compared with ES (P < .0001). The null hypothesis was rejected.. In matched pairs of teeth, intracanal placement of WMTA compared with ES resulted in a higher pH in simulated root resorption defects that was time and root level dependent.

Topics: Aluminum Compounds; Calcium Compounds; Calcium Hydroxide; Calcium Phosphates; Case-Control Studies; Dental Pulp Cavity; Dentin; Diffusion; Drug Combinations; Humans; Hydrogen-Ion Concentration; Hydroxides; Materials Testing; Oxides; Root Canal Filling Materials; Root Canal Irrigants; Root Canal Preparation; Root Resorption; Silicates; Sodium Chloride; Sodium Hypochlorite; Tantalum; Time Factors; Zirconium

This study measured hydroxyl ion diffusion through dentinal tubules into a bathing solution. Eighty single-canal, instrumented teeth were divided into 8 groups. Control groups 1 and 3 were irrigated with 10 mL 0.9% saline and 10 mL 6% sodium hypochlorite (NaOCl), respectively. Control groups 5 and 7 were irrigated with 3 mL and 1 mL 17% ethylenediaminetetraacetic acid (EDTA) and then 10 mL 6% NaOCl, respectively. Experimental groups 2, 4, 6, and 8 were irrigated as groups 1, 3, 5, and 7, followed by placement of calcium hydroxide (Ca(OH)2) into canals. Bathing solution pH was recorded for 30 days, a cementum defect was made, and then pH was recorded for another 30 days. With a paired difference test, average pH during steady state was statistically different and higher after the defect (P < .001). With Tukey multiple comparisons, post-defect pH for group 6 was found to be significantly greater (P < .01) than in other groups. This study indicated final canal irrigation with 3 mL 17% EDTA and 10 mL 6% NaOCl before Ca(OH)2 placement allowed the greatest hydroxyl ion diffusion to the root surface.

Topics: Analysis of Variance; Dental Cementum; Dentin; Edetic Acid; Humans; Hydrogen-Ion Concentration; Hydroxides; Root Canal Irrigants; Smear Layer; Sodium Hypochlorite

This study investigated the effect of passive ultrasonic irrigation (PUI) on diffusion of hydroxyl ions through radicular dentine.. After chemomechanical preparation of root canals in 60 human teeth, the cementoenamel junction and the apical 3 mm of each root were covered with fast-setting adhesive. Four final irrigation protocols were applied (n = 10): group (G)1: irrigation with EDTA + NaOCl; G2: EDTA + PUI + NaOCl; G3: EDTA+(NaOCl + PUI); G4: (EDTA + PUI) + (NaOCl + PUI). Ten teeth irrigated with distilled water followed by PUI (G5) served as the negative control. After drying, the canals were filled with calcium hydroxide paste (CH), sealed and kept in individual vials containing 10 mL of distilled water with known pH values. At 7, 14, and 21 days, the pH of the water in the vials was measured. The pH values in various groups were analyzed with two-way ANOVA (irrigation protocol and time period as factors) and Holm-Sidak multiple comparison test (α = 0.05).. Changes in pH was not significantly different among groups (P = 0.651) but was significant different among different time periods (P < 0.0001). For all groups, ion diffusion was higher at 14 and 21 days than at 7 days.. PUI has no effect on diffusion of hydroxyl ions through radicular dentine. When CH is used as temporary filling material, a waiting period of at least 14 days is required to create an alkaline environment within the radicular dentine.. The use of PUI during final irrigation phase does not improve the action of CH when it is used as temporary filling material.

Topics: Calcium Hydroxide; Dentin; Edetic Acid; Humans; Hydrogen-Ion Concentration; Hydroxides; In Vitro Techniques; Root Canal Filling Materials; Root Canal Irrigants; Root Canal Preparation; Sodium Hypochlorite; Therapeutic Irrigation; Ultrasonics

Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). We confirm the formation of N,N-diisopropylformamide and N,N-diisopropylamine following decontamination of VX with hypochlorite-based solution, whereas they were not detected in extracts of hydroxide-based decontamination solutions by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography-mass spectrometry. We report the electron ionisation and chemical ionisation mass spectroscopic details, retention indices, and NMR spectra of N,N-diisopropylformamide and N,N-diisopropylamine, as well as analytical methods suitable for their analysis and identification in solvent extracts and decontamination residues.

Topics: Chemical Warfare Agents; Decontamination; Formamides; Gas Chromatography-Mass Spectrometry; Humans; Hydroxides; Magnetic Resonance Spectroscopy; Organothiophosphorus Compounds; Propylamines; Sodium Hypochlorite; Solutions

A novel anorganic bovine bone xenograft with enhanced bioactivity and osteoconductivity was prepared by an ion substitution method using sodium hypochlorite. Bovine bone granules were defatted, washed, and then soaked in sodium hypochlorite solution at room temperature. Subsequently, the granules were dried and then heat-treated at 1000°C with sodium hypochlorite. As a control, bovine bone granules were prepared with the same conditions but without sodium hypochlorite treatment. Phase, functional group, and elemental analyses by XRD, FTIR, and EPMA showed that the granules heat-treated without and with sodium hypochlorite were pure hydroxyapatite and sodium-chlorine-bearing hydroxyapatite, respectively. After soaking in simulated body fluid (SBF) for 1 week, low crystalline hydroxyl carbonate apatite fully covered the surface of sodium-chlorine-bearing hydroxyapatite, whereas it formed little on the hydroxyapatite surface. After soaking in SBF and deionized water, ICP-AES and IC analyses showed that the dissolutions of calcium, sodium, chlorine, and hydroxyl ions from sodium-chlorine-bearing hydroxyapatite notably increased compared with those from hydroxyapatite. This resultantly increased the ionic activity product of apatite in SBF and induced new formation of low crystalline hydroxyl carbonate apatite. The cytotoxicity test by BCA assay showed that there were no statistically significant differences between hydroxyapatite and sodium-chlorine-bearing hydroxyapatite. In addition, sodium-chlorine-bearing hydroxyapatite showed better osteoconductivity in the calvarial defects of New Zealand white rabbits within 4 weeks compared with that of hydroxyapatite. The results suggest that this novel anorganic bovine bone xenograft possesses encouraging potential for use as a bone grafting material due to better bioactivity and osteoconductivity than hydroxyapatite.

Topics: 3T3 Cells; Animals; Bone Substitutes; Bone Transplantation; Calcium; Cattle; Hydroxides; Hydroxyapatites; Male; Materials Testing; Mice; Microscopy, Electron, Scanning; Osseointegration; Rabbits; Skull; Sodium Hypochlorite; Spectroscopy, Fourier Transform Infrared; Transplantation, Heterologous; X-Ray Diffraction