Tissue damage after sodium hypochlorite extrusion during root canal treatment

Sodium hypochlorite accident diagnosis and management: Analysis from the literature and the French pharmacovigilance database

PURPOSE

Sodium hypochlorite (NaOCl) is considered as the reference irrigation solution in endodontics. However, NaOCl-related accidents may occur, and non-dentist health professionals might under-recognize this rare adverse effect although it is potentially severe, with possible medical and aesthetic sequelae. We performed a literature review to provide to non-dentist healthcare professionals a large picture of symptoms, management and potential consequences of NaOCl accidents.

METHODS

We queried PubMed and the French Pharmacovigilance database and retrieved 76 cases for analysis (70 from 57 published articles, and six from the database).

RESULTS

The analysis showed that patients were mostly women (79%), aged around of 42 years, undergoing upper jawbone (74%) endodontic procedure. NaOCl concentration ranged from 1% to 10%, with 0.5 to 30 mL injected. Most cases (86%) corresponded to an accidental extrusion beyond the root apex to the periapical tissues, followed by tissular injection by error (8%) and extrusion into the maxillary sinus (3%). Local symptoms always occurred within 24 h, mostly pain (99%), edema (89%) and/or ecchymosis (61%). Complications were mainly neurological (29%), necrotic (22%) and cutaneous (9%). Most of patients (76%) fully recovered after medical management but 18 (24%) required surgical management.

CONCLUSION

Any healthcare professional should be aware of the classical symptomatic triad of NaOCl accident with sudden pain, haemorrhage/ecchymosis and swelling, to start or recommend adequate management. Patients should be reassured, but a close follow-up is necessary to avoid delayed complication.

Evaluation of Nanomagnesium Oxide in Combination with Garlic Extract as an Endodontic Irrigant: An In Vitro Study

AIM

The aim of this in vitro study was to evaluate the effectiveness of the combination of garlic extract in combination with magnesium oxide (MgO) for use as an endodontic irrigant at various contact times.

MATERIALS AND METHODS

All 48 teeth were divided into 6 groups according to irrigation used after inoculation with Enterococcus faecalis and incubation. The control groups consisted of saline and sodium hypochlorite (NaOCl) used as irrigants and the test groups employed garlic extract combined with nano-magnesium oxide (nano-MgO) used as irrigant with two contact times, namely, 2 and 5 minutes, and garlic extract and nano-MgO used solely for 5 minutes each. Colony-forming units (CFUs) were counted after plating and incubation.

RESULTS

In NaOCl, and in both combination groups, there was a significant reduction in CFU counts. The saline group showed no decrease. Statistical analysis showed no difference in efficacy between NaOCl and the two combination groups. There was a statistical difference between the combination group and garlic/nano-MgO alone at both 2 and 5 minutes.

CONCLUSIONS

Under the conditions of this study, a novel irrigant, a combination of nanoparticles of MgO and garlic extract was as effective as NaOCl against E. faecalis in an in vitro model at two tested contact times.

CLINICAL SIGNIFICANCE

Combination of MgO nanoparticles and garlic extract achieves disinfection comparable to gold standard NaOCl without harmful caustic effects of hypochlorite.

Transient apical peak pressure measurement of Er:YAG laser-activated irrigation in different in vitro tooth models using a high-frequency sensor system

The transient apical pressure side effect is an important safety consideration for Er:YAG laser-activated irrigation (LAI). Therefore, this study aimed to measure the transient apical peak pressure (TAPP) of LAI under different laser settings in various tooth models using a high-frequency sensor system. Tooth models with different pulp chamber structures, apical diameters, and curvatures were prepared using transparent resin and filled with deionised water. The Er:YAG laser fibre was placed 3 mm from the root canal orifice. Irrigation was performed at 10-40 mJ and 20-50 Hz using the super short pulse mode. The TAPP was measured using a 50,000-sample/second pressure sensor connected to the models' apices. The TAPP of LAI was significantly higher than that of other chemical preparation methods. Among all investigated factors, pulp chamber anatomy and apical diameters had the greatest effects and were highly related to the apical peak pressure. Root canal curvature showed no direct correlation with TAPP. The larger the final prepared working width, the greater the TAPP. Furthermore, both pulse energy and frequency had positive correlations with TAPP. In conclusion, tooth anatomy factors and laser parameter settings influenced TAPP during Er:YAG LAI. Therefore, proper settings of laser parameters are important to improve the safety of Er:YAG LAI.

Facial hematoma of endodontic origin: A case report

Endodontic treatment is a common procedure in dentistry that consists of elimination of organic tissues, infected debris, and pathogenic bacteria from the canal system by means of mechanical instrumentation associated with abundant disinfecting agents (Haapasalo et al., 2005) [1]. Despite progress with its implementation, dentists may at any time be faced with complications during or after a root canal procedure. While some of these problems can be anticipated, many can never really be predicted. A complication such as a hematoma that is usually seen as a complication of trauma or oral surgery, is rarely seen after a simple endodontic treatment. It put the dentist in a confused and uncomfortable situation. Dentists should be aware of the possible occurrence of this incident and should know what can cause it and how to manage it.

We report the case of a 63-year-old patient, referred by her general dentist to our center for the sudden onset of a facial hematoma after endodontic treatment.

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Facial Hematoma is a well-known and recognized complication in oral and maxillofacial surgery or in facial trauma.

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Hematoma is a rare, unknown, and unexpected complication after routine canal therapy.

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It can be an accident of sodium hypochlorite by extrusion of the solution through root apices.

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It is responsible of important morbidity.

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To avoid hypochlorite accidents, particularly hematoma, some recommendations must be followed, and the basics of endodontic treatment must be respected.

Effect of intracanal cryotherapy on postoperative pain after endodontic treatment: systematic review with meta-analysis

Objectives

This study aimed to evaluate the effectiveness of final irrigation with cold saline solution after endodontic treatment compared with saline solution at room temperature against postoperative pain following endodontic treatment.

Materials and Methods

A broad search was performed in the PubMed, Web of Science, Scopus, Cochrane Library, Virtual Health Library (LILACS), and Grey Literature databases. Two independent reviewers performed data extraction, risk of bias using the Cochrane methodology, and certainty of evidence using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

Results

Eight studies were included in qualitative synthesis. Intracanal cryotherapy favored the reduction of postoperative pain in the systematic review. Four studies were included in meta-analyses. The meta-analysis showed that intracanal cryotherapy reduced postoperative pain in teeth with symptomatic apical periodontitis (SAP) at 24 hours. There was no association between intracanal cryotherapy and control (room temperature) groups in teeth with normal periapical tissue with respect to postoperative pain at 24 hours and 48 hours.

Conclusions

Intracanal cryotherapy was effective in reducing postoperative pain after endodontic treatment in teeth with SAP.

Accidental Extrusion of Sodium Hypochlorite in a Patient Taking Alendronate: A Case Report With an 8-Year Follow-up

Extrusion of sodium hypochlorite (NaOCl) is a very rare accident with the most common complications including pain, swelling, and hematoma. It can occur even if procedural guidelines, predisposing conditions, and risk factors are taken into consideration. A 59-year-old female patient was admitted to the endodontics department to treat a left maxillary first premolar (World Dental Federation tooth 24). The medical history included osteoporosis and systemic medication with alendronate. Initially, the diagnosis was "symptomatic irreversible pulpitis" with "normal apical tissues." During instrumentation of the buccal canal, accidental extrusion of 2.5% NaOCl occurred into the periapical tissues, resulting from misinterpretation of the working length, and caused severe pain and bleeding. The canal was immediately flushed using copious irrigation with saline solution. An analgesic and corticosteroid were prescribed. At 3 and 7 days, ecchymosis and slight hematoma were observed extraorally in the area of the affected tooth and an intraoral ulceration at the apex of the affected tooth. At 15 days, minimal signs of ecchymosis were observed, and the treatment was resumed. At 30 days after the accident, there was complete remission of the sequelae. The clinical, radiographic, and tomographic assessment after 1 month, 1 year, and 8 years showed favorable case evolution. During the 8-year follow-up, the patient maintained the systemic use of alendronate. It can be concluded that NaOCl extrusion is an accident that causes patients and clinicians to experience an unpleasant consequence. The radiographic working length should always be determined carefully. A successful outcome can be achieved in patients who take alendronate.

Sesquiterpene Lactones from Cotula cinerea with Antibiotic Activity against Clinical Isolates of Enterococcus faecalis

Cotula cinerea, belonging to the tribe Anthemideae, is a plant widespread in the Southern hemisphere. It is frequently used in folk medicine in North African countries for several of its medical properties, shown by its extracts and essential oils. The dichloromethane extract obtained from its aerial parts demonstrated antibiotic activity against Enterococcus faecalis and was fractionated by bioguided purification procedures affording five main sesquiterpene lactones. They were identified by spectroscopic methods (NMR and ESIMS data) as guaiantrienolides, i.e., 6-acetoxy-1β-,6-acetoxy-1α-, and 6-acetoxy-10-β-hydroxyguaiantrienolide (1-3), and germacrenolides, i.e., haagenolide and 1,10-epoxyhaagenolide (4 and 5). The absolute configuration was assigned by applying the advanced Mosher's method to haagenolide and by X-ray diffraction analysis to 1,10-epoxyhaagenolide. The specific antibiotic and antibiofilm activities were tested toward the clinical isolates of Enterococcus faecalis. The results showed that compounds 3-5 have antibacterial activity against all the strains of E. faecalis, while compound 2 exhibited activity only toward some strains. Compound 1 did not show this activity but had only antibiofilm properties. Thus, these metabolites have potential as new antibiotics and antibiofilm against drug resistant opportunistic pathogens.

Essential Oils as Alternatives for Root-Canal Treatment and Infection Control against Enterococcus faecalis—A Preliminary Study

Since natural alternatives are needed in dentistry for the treatment of root canal, where the standard irrigant is NaOCl with significant toxicity, the aim of the study was to assess the antibacterial properties of non-chemical root-canal irrigants (aqueous extracts of oregano, thyme, lemongrass, melaleuca and clove essential oils) against Enterococcus faecalis. For this, aqueous extracts of each essential oil (AqEO) were prepared. A solution of sodium hypochlorite (NaOCl) was used as a positive standard against which the antimicrobial effects of AqEO could be reported. The root canals of seven teeth were inoculated with 20 µL of Enterococcus faecalis ATCC29212 inoculum and incubated overnight at 37 °C. All the teeth canals were instrumented and were irrigated with the corresponding AqEO, NaOCl and saline solution, then rinsed with saline. Bacteriological samples for each canal post-instrumentation were collected with sterile paper points which were inoculated on culture media. A second processing followed the same methodology but involved only irrigation and no instrumentation. Using instrumentation, thyme and clove completely inhibited Enterococcus faecalis growth. Without instrumentation, clove and oregano AqEOs completely reduced the bacterial load as seen in direct inoculation, but bacterial growth was observed in all the samples after enrichment, except for NaOCl. Nevertheless, the turbidity of the enrichment media was lower for the samples irrigated with AqEOs than for control. In conclusion, AqEOs of thyme, oregano and clove showed a promising antibacterial effect, especially when teeth instrumentation was performed.

Sodium Hypochlorite Extrusion Accidents: Management and Medico-Legal Considerations

Sodium hypochlorite is considered the most widely used irrigant in endodontics as it exhibits effective antimicrobial activity and has potent tissue-dissolving ability. Whilst it is considered safe when used within the confines of the root canal system, it can cause serious complications when inadvertent periradicular extrusion occurs. This article outlines the complications of sodium hypochlorite extrusion and reviews the appropriate management based on the contemporary evidence. Preventive measures are suggested and the relevant medico-legal considerations are outlined.

Biocompatible combinations of nisin and licorice polyphenols exert synergistic bactericidal effects against Enterococcus faecalis and inhibit NF-κB activation in monocytes

Enterococcus faecalis is one of the bacterial species most frequently isolated from persistent endodontic and apical periodontal infections. The aim of the present study was to evaluate the synergistic antibacterial effects of nisin and selected licorice polyphenols (glabridin, licoricidin, licochalcone A) against planktonic and biofilm-embedded E. faecalis cells. The biocompatibility and anti-inflammatory properties of the nisin/licorice polyphenol combinations were also investigated. The lantibiotic bacteriocin (nisin), the two isoflavonoids (glabridin, licoricidin), and the chalcone (licochalcone A) efficiently inhibited the growth of E. faecalis, with MICs ranging from 6.25 to 25 µg/mL. Combining nisin with each licorice polyphenol individually resulted in a significant synergistic antibacterial effect. Following a 30-min contact, nisin in combination with either glabridin, licoricidin, or licochalcone A caused significant biofilm killing. The nisin/licorice polyphenol combinations had no cytotoxic effects (oral epithelial cells, gingival fibroblasts, and stem cells of the apical papilla), with the exception of nisin/glabridin, when used at their MICs. Lastly, we showed that nisin/glabridin, nisin/licoricidin, and nisin/licochalcone A inhibit NF-κB activation induced by E. faecalis in a monocyte model, suggesting that these combinations possess anti-inflammatory properties. The present study provides evidence that combinations of nisin and glabridin, licoricidin, or licochalcone A show promise as root canal disinfection agents.

Antimicrobial activities of natural plant compounds against endodontic pathogens and biocompatibility with human gingival fibroblasts

OBJECTIVES

The aim of the present study was to investigate three licorice-derived polyphenols (glabridin, licochalcone A, licoricidin) as well as cinnamon oil for their antimicrobial activities against major endodontic pathogens: Enterococcus faecalis, Streptococcus mutans, Actinomyces israelii, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas endodontalis, and Candida albicans. The synergistic interactions between the four compounds and chlorhexidine were assessed on E. faecalis. Lastly, the biocompatibility of the tested compounds was assessed using human gingival fibroblasts.

DESIGN

Minimal inhibitory concentrations (MIC) and minimal microbicidal concentrations (MMC) were determined using a microplate dilution assay. A luminescence assay monitoring adenosine triphosphate was used to assess the antimicrobial activity of the tested compounds against E. faecalis biofilm. The synergistic effects of the tested compounds in association with chlorhexidine were evaluated using the checkerboard technique. Cytotoxicity toward human gingival fibroblasts was assessed by determination of cell metabolic activity using a colorimetric assay.

RESULTS

Cinnamon oil showed the strongest microbicidal activity. Licochalcone A, licoricidin, and glabridin had MIC values ranging from 1.56 to 25 μg/mL against the six endodontic bacterial pathogens. The natural plant compounds were active to various extents against E. faecalis embedded in a biofilm. Synergistic antibacterial effects between chlorhexidine and the compounds, mainly glabridin, were observed against E. faecalis. Following a 2-h exposure, licochalcone A, licoricidin, and glabridin demonstrated no cytotoxicity toward gingival fibroblasts at concentrations up to 50 μg/mL, while cinnamon oil and, to a lesser extent, chlorhexidine displayed some cytotoxicity.

CONCLUSIONS

The present study provides evidence that the natural plant compounds tested show promise as root canal disinfection agents.

Effect of Pulse Energy, Pulse Frequency, and Tip Diameter on Intracanal Vaporized Bubble Kinetics and Apical Pressure During Laser-Activated Irrigation Using Er:YAG Laser

Objective: Er:YAG laser-activated irrigation (LAI) is an effective method of root canal cleaning, but irrigant extrusion from the apical foramen has been a concern. We aimed to analyze the effects of pulse energy, pulse frequency, and laser tip diameter on intracanal vapor bubble kinetics and periapical pressure generation during LAI with Er:YAG laser. Background: Irrigant vapor bubble kinetics are one of indices of root canal cleaning efficacy. However, few studies have compared laser pulse conditions to vapor bubble kinetics, in relation to periapical pressure. Methods: A plastic root canal model (apical diameter 0.50 mm, 6% taper, 20 mm long) was filled with distilled water, and LAI with Er:YAG laser (Erwin AdvErl Unit; 30, 50, or 70 mJ; 10, or 20 pulses per second; laser tip R200T or R600T) was performed with the end of the tip fixed at 15 mm from the root apex. The number, maximum diameter, and velocity of vapor bubbles were analyzed by high-speed video imaging. Pressure generated outside the apical foramen was measured with a pressure sensor. Results: Vapor bubble count and maximum diameter increased significantly with pulse energy, pulse frequency, and tip diameter. Vapor bubble velocity increased significantly with pulse frequency, but not with pulse energy or tip diameter. Periapical pressure increased significantly with pulse energy, pulse frequency, and tip diameter. Conclusions: The pulse frequency was the single factor that significantly affected all the examined parameters (the number, diameter, and velocity) of vapor bubble kinetics together with the periapical pressure.

Endodontic irrigants: Different methods to improve efficacy and related problems

Shaping and cleaning a root canal system along with the preservation of the surrounding periodontal tissues are the principal goals of an endodontic treatment. While most of the attention is paid to the mechanical aspects of a root canal treatment, an essential feature of it is the irrigation. All over the years, many materials have been used to clean the root canal of a tooth, and certainly, the sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid solutions are the most used and most reliable ones. Putting them inside of a canal is mostly done using a normal syringe, but many techniques have been involved in this process, including the use of sonic/ultrasonic instruments, the use of shaping files, and even laser, to increase the efficacy of irrigant solutions, especially of NaOCl one. Each one of this technique faces some disadvantages, just as the vapor lock effect and the apical extrusion, and has a different action on features such as the reaction rate and the shear stress of an endodontic irrigant solution. In this narrative review, we describe the different features of many irrigant solutions and the different ways of upgrading their efficacy in the cleaning of a root canal system, with the use of tables to summarize the entire description, and drawing the readers' attention to a photographic illustration for a better understanding of the topic.

Evaluation of the antimicrobial efficacy of 20% Punica granatum, 0.2% chlorhexidine gluconate, and 2.5% sodium hypochlorite used alone or in combinations against Enterococcus faecalis: An in-vitro study

Objectives

The study was aimed at evaluating the antimicrobial efficacy of 20% Punica granatum, 0.2% chlorhexidine (CHX) gluconate, and 2.5% sodium hypochlorite used alone or in combinations against Enterococcus faecalis.

Materials and Methods

Aqueous extract of pomegranate peel was prepared in the Pharmacology Departmental Laboratory. A total of 240 wells were prepared (40 for each group) with 5 wells per with a diameter of 6 mm and depth of 4 mm at equidistant from each other. Using a pipette, each well was filled with 50 μl of the test irrigant solution. CHX (0.2%), 2.5% sodium hypochlorite, and aqueous extract of pomegranate peel and their combinations were tested as root canal irrigants against a standard strain of E. faecalis (ATCC 29212) on sheep blood agar plate by calculating the zones of inhibition. The mean diameter of zones was calculated and tabulated. Data were analyzed using one-way analysis of variance and Tukey's post hoc test. Descriptive statistics was obtained using SPSS software (version 11.5) with P established at < 0.05.

Results

Combination of Punica granatum with sodium hypochlorite and CHX showed maximum mean zones of inhibition with mean of 23.9 and 25.7 mm, respectively, and showed significantly better results than all other groups either irrigants used alone or in combinations.

Conclusions

Punica granatum and CHX was proved to be a very good combination among experimental groups against E. faecalis, and sodium hypochlorite was least effective against E. Faecalis.

The Effect of Sodium Hypochlorite and Chlorhexidine as Irrigant Solutions for Root Canal Disinfection: A Systematic Review of Clinical Trials

INTRODUCTION

This systematic review aimed to compare the effectiveness of sodium hypochlorite and chlorhexidine for root canal disinfection during root canal therapy.

METHODS

A literature search for clinical trials was made on the PubMed (MEDLINE), Web of Knowledge, SCOPUS, and Science Direct databases and in the reference lists of the identified articles up to January 2015. Quality assessment of the selected studies was performed according to the Consolidated Standards of Reporting Trials statement.

RESULTS

One clinical trial and 4 randomized clinical trials were selected from the 172 articles initially identified. There was heterogeneity in the laboratory methods used to assess the root canal disinfection as well as in the concentrations of the irrigants used. Therefore, meta-analysis was not performed. Two studies reported effective and similar reductions in bacterial levels for both irrigants. Sodium hypochlorite was more effective than chlorhexidine in reducing microorganisms in 1 study, and another reported opposite findings. Both root irrigants were ineffective in eliminating endotoxins from necrotic pulp root canals in 1 study. Trial design and information regarding randomization procedures were not clearly described in the clinical trials. No study compared laboratory results with clinical outcomes.

CONCLUSIONS

The available evidence on this topic is scarce, and the findings of studies were not consistent. Additional randomized clinical trials using clinical outcomes to compare the use of sodium hypochlorite and chlorhexidine during root canal therapy are needed.

Effect of Temperature, Concentration and Contact Time of Sodium Hypochlorite on the Treatment and Revitalization of Oral Biofilms

Background and aims. Increasing the temperature of sodium hypochlorite (NaOCl) enhances its dissolution and antibacterial properties. However, the high resistance of multi-species biofilms could restrict the effect of the solution regardless of its temperature, enabling the long-term recovery of the surviving bacteria. The aim of this study was to investigate if the increase of temperature of NaOCl improves its antibacterial and dissolution ability on oral biofilms and if the post-treatment remaining bacteria were capable of growing in a nutrient-rich medium.

Materials and methods. Forty dentin blocks were infected intra-orally for 48 hours. Then, the specimens were treated with 1% and 2.5% NaOCl at room temperature (22ºC) and body temperature (37ºC) for 5 and 20 min. The percentage of live cells and the biovolume were measured pre- (control) and post-treatment and after the biofilm revitalization. Four confocal ‘stacks’ were chosen from random areas of each sample. Statistical analysis was performed using Kruskal-Wallis and Dunn tests. Statistical significance was defined at P <0.05.

Results. All the NaOCl groups were effective in dissolving the biofilm at any temperature, concentration and contact time without statistical differences among them (P >0.05). The 1%-NaOCl for 5min was not able to significantly kill the bacteria, regardless of its temperature and contact time (P >0.05).

Conclusion. The temperature variation of the NaOCl was not relevant in killing or dissolving bacterial biofilms. Twenty-four hours of reactivation did not appear to be enough time to induce a significant bacterial growth.

Guidelines for management of sodium hypochlorite extrusion injuries

Sodium hypochlorite (NaOCl) is the most common irrigant used in modern endodontics. It is highly effective at dissolving organic debris and disinfecting the root canal system due to the high pH. Extravasation of NaOCl into intra-oral and extra-oral tissues can lead to devastating outcomes leading to long-term functional and aesthetic deficits. Currently no clear guidelines are available which has caused confusion among the dental and oral and maxillofacial (OMFS) surgical community how best to manage these patients. Following a literature review and considering our own experience we have formulated clear and precise guidelines to manage patients with NaOCl injury.

Inadvertent apical extrusion of sodium hypochlorite with evaluation by dental volumetric tomography

This case report describes the tissue injury caused by inadvertently extruded NaOCl through the apical constriction. A 56-year-old female patient with complaints of pain, swelling, and ecchymosis on the left side of her face was referred to our clinic. The symptoms had emerged following root canal treatment of the maxillary left first premolar, and a soft tissue complication due to apical extrusion of NaOCl was diagnosed. Antibiotics and analgesics were prescribed. DVT images revealed that the buccal root apex had perforated the maxillary bone. The patient was followed up every other day and became asymptomatic on the 10th day. Endodontic therapy was completed with routine procedures. Determining working length precisely and following irrigation protocols meticulously are indispensable to prevent this type of complication. 3D visualization of the affected area may reveal the cause of the incident.

An in vitro evaluation of the cytotoxicity of varying concentrations of sodium hypochlorite on human mesenchymal stem cells

AIM

To evaluate and compare the cytotoxicity of various concentrations of sodium hypochlorite on immortalized human bone marrow mesenchymal stem cells (MSCs).

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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 mandatory to evolve a consensus on the optimal concentration of sodium hypochlorite to be used as endodontic irrigant.

Cytotoxicity of QMix™ endodontic irrigating solution on human bone marrow mesenchymal stem cells

Background

Debridement and disinfection of the root canal system is a crucial step in endodontic procedures. The effectiveness of irrigation relies on both the mechanical flushing action and the ability of irrigants to dissolve tissue and kill bacteria. The objective of the present study is to evaluate and compare the cytotoxicity of QMix™ root canal irrigating solution on immortalized human bone marrow mesenchymal stem cells (hTERT-MSC-C1) and to compare it with that of sodium hypochlorite (NaOCl).

Methods

Immortalized human bone marrow mesenchymal stem cells (hTERT-MSCs) were exposed to QMix™ and NaOCl. Cell viability was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alamarBlue assays. The cell morphology was studied after two hours of exposure to QMix™ and NaOCl. Scanning electron microscopy (SEM) analyses were performed after 2- and 4-hour incubation periods. Finally, ethidium bromide/acridine orange (EB/AO) fluorescent stain was applied to the cells in the 8-chamber slides after they were incubated with the testing agents for 2 hours to detect live and dead cells. The observations were tabulated and analyzed statistically.

Results

QMix™ exposure resulted in a significantly higher percentage of cell viability than NaOCl in the MTT and alamarBlue assays at three time points compared to the control. The SEM analysis demonstrated minimal morphological changes associated with cells that were exposed to the QMix™ solution, with little shrinkage and fragmentation of the cell wall. The live/dead analysis showed that the number of live cells after exposure to QMix™ was similar to that of the untreated control. No cell structure could be observed with the NaOCl group, indicating cell lysis.

Conclusion

Both the QMix™ and NaOCl solutions were toxic to human bone marrow MSCs. Each solution might have induced cell death in a different way as evidenced in the cell viability, SEM and fluorescent studies. The slower cell death induced by QMix™ might therefore be less aggressive and more acceptable to living tissues.

Iatrogenic subcutaneous emphysema of endodontic origin - case report with literature review

Surgical emphysema is well known and many case reports have been published on this. Many authors have reported this as a complication post dentoalveolar treatment. Diffusion of air into facial planes and periorbital area during endodontic procedures has been rarely reported. The use of three way air syringe and forceful irrigation of root canal can lead to surgical emphysema of subcutaneous tissue planes in and around the teeth which are involved. This case report highlights one such complication seen during endodontic treatment, discusses aetiology, complications and conservative management of this dental office emergency.

Anatomy of sodium hypochlorite accidents involving facial ecchymosis - a review

OBJECTIVES

Root canal treatment forms an essential part of general dental practice. Sodium hypochlorite (NaOCl) is the most commonly used irrigant in endodontics due to its ability to dissolve organic soft tissues in the root canal system and its action as a potent antimicrobial agent. Although NaOCl accidents created by extrusion of the irrigant through root apices are relatively rare and are seldom life-threatening, they do create substantial morbidity when they occur.

METHODS

To date, NaOCl accidents have only been published as isolated case reports. Although previous studies have attempted to summarise the symptoms involved in these case reports, there was no endeavour to analyse the distribution of soft tissue distribution in those reports. In this review, the anatomy of a classical NaOCl accident that involves facial swelling and ecchymosis is discussed.

RESULTS

By summarising the facial manifestations presented in previous case reports, a novel hypothesis that involves intravenous infusion of extruded NaOCl into the facial vein via non-collapsible venous sinusoids within the cancellous bone is presented.

CONCLUSIONS

Understanding the mechanism involved in precipitating a classic NaOCl accident will enable the profession to make the best decision regarding the choice of irrigant delivery techniques in root canal débridement, and for manufacturers to design and improve their irrigation systems to achieve maximum safety and efficient cleanliness of the root canal system.

Tissue resistance to soft tissue emphysema during minimally invasive periodontal surgery

AIM

The aim of this study was to determine the pressure where oral soft tissue resistance will be overcome resulting in soft tissue emphysema and to measure the safety of an antifouling device for a videoscope used during minimally invasive periodontal surgery.

MATERIALS AND METHODS

Resistance was measured in vitro in porcine tissue. One study arm measured palatal tissue resistance to air applied through a needle. Another arm measured resistance in a surgical access for minimally invasive periodontal surgery (MIS). India ink was placed on the tissue,pressure at 0,3,10,15,20, and 25 pounds/square inch (psi)applied, and penetration of India ink into the tissue was measured. Three trials in three sites were performed at each pressure in both arms of the study.

RESULTS

Pressure applied to palatal tissue through a needle showed no significant penetration of India ink until 15 psi (0.90 ± 0.24 mm, p = 0.008). Penetration considered clinically significant was noted at 20 and 25 psi (4 to 6 mm, p ≤ 0.0001). No significant penetration was noted in minimally invasive incisions.

CONCLUSION

Within the test system, pressures of 15 psi or less seem unlikely to cause soft tissue emphysema. No evidence of tissue emphysema was noted with the video scope antifouling device.

CLINICAL SIGNIFICANCE

The use of pressures greater than 15 pounds per square inch should be avoided during surgical procedures. The antifouling device for a videoscope appears safe for use during minimally invasive periodontal surgery.