Anatomy of sodium hypochlorite accidents.

Division of Endodontics, University of Colorado, School of Dental Medicine, Aurora, USA.
Compendium of continuing education in dentistry (Jamesburg, N.J.: 1995) 11/2007; 28(10):544-6, 548, 550.
Source: PubMed

ABSTRACT Sodium hypochlorite (NaOCl) in various concentrations is the most widely used endodontic irrigant, but it can be an irritant to vital tissues. There are several reports about the complications of irrigation with NaOCl during root canal therapy. Most of the complications are the result of accidental extrusion of the solution from the apical foramen or accessory canals or perforations into the periapical area. This article is a review and comparison of all reported NaOCl accidents in the literature.

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    ABSTRACT: To evaluate and compare the cytotoxicity of various concentrations of sodium hypochlorite on immortalized human bone marrow mesenchymal stem cells (MSCs). The 5.25 percent sodium hypochlo-rite (NaOCl) at concentrations of 0.5, 0.1, 0.025, 0.0125, and 0.005 mg/ml were used to assess the cytotoxic effect on MSCs. Immortalized human bone marrow mesenchymal stem cells (hTERT-MSCs) were exposed to NaOCl at 5 different concentrations. Cell viability was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alamarBlue assays. The cell morphology changes were assessed with scanning electron microscopy (SEM) after exposure to 2, 4, and 24 hour incubation. The ethidium bromide/acridine orange (EB/ AO) fuorescent stain was applied to the cells in the 8-chamber slides after they were incubated with the testing agents for 2 and 4 hours to detect live and dead cells. The observations were quantitatively and qualitatively analyzed. The cell viability study using MTT assay and AB assay showed significant reduction with varying concentration at 2 and 4 hours incubation period. The cell viability decreased with the higher percentage of NaOCl. The exposure time also revealed an inverse relation to the cell viability. The SEM analysis showed reduction in the number of cells and morphological alterations with 0.5 mg/ml at 2 and 4 hours compared to 0.025 mg/ml NaOCl. Destruction of the cells with structural alterations and lysis was evident under fuorescence microscope when the cells were exposed to 0.5 mg/ml NaOCl. Within the limitations of this in vitro study it can be concluded that NaOCl is toxic to the human bone marrow MSCs. The cell lysis was evident with higher concentration of sodium hypochlorite. From the observations, it can be concluded that a lower concentration of NaOCl may be used as endodontic irrigant due to its cytotoxic properties. Further studies are man- datory to evolve a consensus on the optimal concentration of sodium hypochlorite to be used as endodontic irrigant. Sodium hypochlorite, Cytotoxicity, Mesenchymal stem cells, Antimicrobial activity, Irrigation solutions. How to cite this article: Alkahtani A, Alkahtany SM, Anil S. An in vitro Evaluation of the Cytotoxicity of Varying Concentrations of Sodium Hypochlorite on Human Mesenchymal Stem Cells. J Contemp Dent Pract 2014;15(4):473-481. Source of support: Nil Conflict of interest: None declared.
    The journal of contemporary dental practice 05/2014; 15(4):473-81. DOI:10.5005/jp-journals-10024-1565
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    ABSTRACT: Apical extrusion of debris and irrigants during cleaning and shaping of the root canal is one of the main causes of periapical inflammation and postoperative flare-ups. The purpose of this study was to quantitatively measure the amount of debris and irrigants extruded apically in single rooted canals using two reciprocating and one rotary single file nickel-titanium instrumentation systems. Sixty human mandibular premolars, randomly assigned to three groups (n = 20) were instrumented using two reciprocating (Reciproc and Wave One) and one rotary (One Shape) single-file nickel-titanium systems. Bidistilled water was used as irrigant with traditional needle irrigation delivery system. Eppendorf tubes were used as test apparatus for collection of debris and irrigant. The volume of extruded irrigant was collected and quantified via 0.1-mL increment measure supplied on the disposable plastic insulin syringe. The liquid inside the tubes was dried and the mean weight of debris was assessed using an electronic microbalance. The data were statistically analysed using Kruskal-Wallis nonparametric test and Mann Whitney U test with Bonferroni adjustment. P-values less than 0.05 were considered significant. The Reciproc file system produced significantly more debris compared with OneShape file system (P<0.05), but no statistically significant difference was obtained between the two reciprocating instruments (P>0.05). Extrusion of irrigant was statistically insignificant irrespective of the instrument or instrumentation technique used (P >0.05). Although all systems caused apical extrusion of debris and irrigant, continuous rotary instrumentation was associated with less extrusion as compared with the use of reciprocating file systems.
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