Comparison of CaOH with MTA for direct pulp capping: a PBRN randomized clinical trial

This practice-based, randomized clinical trial evaluated and compared the success of direct pulp capping in permanent teeth with MTA (mineral trioxide aggregate) or CaOH (calcium hydroxide). Thirty-five practices in Northwest PRECEDENT were randomized to perform direct pulp caps with either CaOH (16 practices) or MTA (19 practices). Three hundred seventy-six individuals received a direct pulp cap with CaOH (n = 181) or MTA (n = 195). They were followed for up to 2 yrs at regular recall appointments, or as dictated by tooth symptoms. The primary outcomes were the need for extraction or root canal therapy. Teeth were also evaluated for pulp vitality, and radiographs were taken at the dentist's discretion. The probability of failure at 24 mos was 31.5% for CaOH vs. 19.7% for MTA (permutation log-rank test, p = .046). This large randomized clinical trial provided confirmatory evidence for a superior performance with MTA as a direct pulp-capping agent as compared with CaOH when evaluated in a practice-based research network for up to 2 yrs.

Oxidative release of natural glycans for functional glycomics

Glycans have essential roles in biology and the etiology of many diseases. A major hurdle in studying glycans through functional glycomics is the lack of methods to release glycans from diverse types of biological samples. Here we describe an oxidative strategy using household bleach to release all types of free reducing N-glycans and O-glycan-acids from glycoproteins, and glycan nitriles from glycosphingolipids. Released glycans are directly useful in glycomic analyses and can be derivatized fluorescently for functional glycomics. This chemical method overcomes the limitations in glycan generation and promotes archiving and characterization of human and animal glycomes and their functions.

Present status and future directions - irrigants and irrigation methods

Irrigation is considered the primary means of cleaning and disinfection of the root canal system. The purpose of this review was to set the framework for the obstacles that irrigation needs to overcome, to critically appraise currently used irrigants and irrigation methods, to highlight knowledge gaps and methodological limitations in the available studies and to provide directions for future developments. Organization of bacteria in biofilms located in anatomic intricacies of the root canal system and the difficulty to eliminate them is the main challenge for irrigants. Sodium hypochlorite remains the primary irrigant of choice, but it needs to be supplemented by a chelator. Delivery of the irrigants using a syringe and needle and activation by an ultrasonic file are the most popular irrigation methods. There is no evidence that any adjunct irrigation method, including ultrasonic activation, can improve the long‐term outcome of root canal treatment beyond what can be achieved by instrumentation and syringe irrigation. It is necessary to redefine the research priorities in this field and investigate in greater depth the penetration of the irrigants, their effect on the biofilm and the long‐term treatment outcome. New studies must also focus on clinically relevant comparisons, avoid methodological flaws and have sufficiently large sample sizes to reach reliable conclusions. Future multidisciplinary efforts combining the knowledge from basic sciences such as Chemistry, Microbiology and Fluid Dynamics may lead to more effective antimicrobials and improved activation methods to bring them closer to the residual biofilm in the root canal system.

Antibiofilm activity of three irrigation protocols activated by ultrasonic, diode laser or Er:YAG laser in vitro

AIM

To investigate the impact of three irrigation protocols, activated by three different methods, on mature biofilms of Enterococcus faecalis in vitro.

METHODOLOGY

Root canals in 280 single-rooted teeth were instrumented using a rotary Ni-Ti system. Biofilms of E. faecalis were generated based on a previously established protocol. Samples were randomly divided into three experimental (n = 80) and one control (n = 40) group based on the irrigation protocol employed: group 1 (NaOCl + Etidronic acid), 1 : 1 mixture of 6% NaOCl and 18% etidronic acid; group 2 (NaOCl-EDTA), 3% NaOCl followed by 17% EDTA; group 3 (NaOCl-EDTA-NaOCl), 3% NaOCl followed by 17% EDTA and a final flush of 3% NaOCl. Saline served as the control. Samples were further divided into four subgroups (n = 20) based on the activation method: subgroup A, no activation; subgroup B, ultrasonic activation; group C, diode laser; group D, Er:YAG laser. Confocal laser scanning microscopy was used to assess bacterial viability in situ. Root dentine powder was obtained for determining the colony-forming units (CFU mL(-1) ). Data were analysed by appropriate statistical analyses with P = 0.05.

RESULTS

All experimental irrigation protocols caused complete destruction of the biofilm in the root canal lumen. Within the dentinal tubules, all groups had a significantly higher percentage of dead bacteria than the saline control (P < 0.05). There was no significant difference between NaOCl + etidronic acid and NaOCl-EDTA-NaOCl (P > 0.05), whereas both groups brought about more bacterial reduction than NaOCl-EDTA (P < 0.05). There was no significant difference between diode laser and Er:YAG laser in any of the groups (P > 0.05). Both diode and Er:YAG laser were more effective than ultrasonic activation and conventional syringe irrigation in reducing E. fecalis biofilms (P < 0.05).

CONCLUSIONS

The use of NaOCl after or in combination with a chelator caused the greatest reduction of E. faecalis. Diode laser and Er:YAG laser activation were superior to ultrasonics in dentinal tubule disinfection.

Surviving Reactive Chlorine Stress: Responses of Gram-Negative Bacteria to Hypochlorous Acid

Sodium hypochlorite (NaOCl) and its active ingredient, hypochlorous acid (HOCl), are the most commonly used chlorine-based disinfectants. HOCl is a fast-acting and potent antimicrobial agent that interacts with several biomolecules, such as sulfur-containing amino acids, lipids, nucleic acids, and membrane components, causing severe cellular damage. It is also produced by the immune system as a first-line of defense against invading pathogens. In this review, we summarize the adaptive responses of Gram-negative bacteria to HOCl-induced stress and highlight the role of chaperone holdases (Hsp33, RidA, Cnox, and polyP) as an immediate response to HOCl stress. We also describe the three identified transcriptional regulators (HypT, RclR, and NemR) that specifically respond to HOCl. Besides the activation of chaperones and transcriptional regulators, the formation of biofilms has been described as an important adaptive response to several stressors, including HOCl. Although the knowledge on the molecular mechanisms involved in HOCl biofilm stimulation is limited, studies have shown that HOCl induces the formation of biofilms by causing conformational changes in membrane properties, overproducing the extracellular polymeric substance (EPS) matrix, and increasing the intracellular concentration of cyclic-di-GMP. In addition, acquisition and expression of antibiotic resistance genes, secretion of virulence factors and induction of the viable but nonculturable (VBNC) state has also been described as an adaptive response to HOCl. In general, the knowledge of how bacteria respond to HOCl stress has increased over time; however, the molecular mechanisms involved in this stress response is still in its infancy. A better understanding of these mechanisms could help understand host-pathogen interactions and target specific genes and molecules to control bacterial spread and colonization.

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.

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.

Large scale extraction of poly(3-hydroxybutyrate) from Ralstonia eutropha H16 using sodium hypochlorite

Isolation of polyhydroxyalkanoates (PHAs) from bacterial cell matter is a critical step in order to achieve a profitable production of the polymer. Therefore, an extraction method must lead to a high recovery of a pure product at low costs. This study presents a simplified method for large scale poly(3-hydroxybutyrate), poly(3HB), extraction using sodium hypochlorite. Poly(3HB) was extracted from cells of Ralstonia eutropha H16 at almost 96% purity. At different extraction volumes, a maximum recovery rate of 91.32% was obtained. At the largest extraction volume of 50 L, poly(3HB) with an average purity of 93.32% ± 4.62% was extracted with a maximum recovery of 87.03% of the initial poly(3HB) content. This process is easy to handle and requires less efforts than previously described processes.

Effect of Different Concentrations of Sodium Hypochlorite on Outcome of Primary Root Canal Treatment: A Randomized Controlled Trial

INTRODUCTION

The aim of this study was to evaluate the effect of 2 different concentrations of sodium hypochlorite on healing and postoperative pain after primary endodontic treatment.

METHODS

One hundred mandibular molars with pulp necrosis and chronic apical periodontitis were randomly assigned to 2 treatment groups: high-concentration (HC) 5% sodium hypochlorite and low-concentration (LC) 1% sodium hypochlorite. Root canal treatment was performed using a standardized protocol. Canals were prepared using equal volumes of respective irrigants after each instrument change. After chemomechanical preparation, the final flush was performed with 5 mL 17% EDTA solution followed by 5 mL 5% or 1% sodium hypochlorite depending on the group. All patients were asked to record the degree of pain on a visual analog scale every 24 hours for 1 week. At the second visit, canals were obturated, and the teeth were restored permanently. Clinical and radiographic evaluations were performed every 3 months for 12 months. The data collected were statistically analyzed.

RESULTS

Eighty-six teeth were available for evaluation at the 1-year follow-up. The overall healing rate observed was 76.7%. Greater healing was observed in the HC (81.4%) group compared with the LC group (72.1%), but the difference was not statistically significant (P > .05). No significant differences in pain incidence and pain scores were found between the 2 groups (P >.05), with lower values reported in the LC group.

CONCLUSIONS

The use of LC or HC sodium hypochlorite did not result in a significant difference in the clinical outcome.

Comparison of the bactericidal efficacy of photodynamic therapy, 2.5% sodium hypochlorite, and 2% chlorhexidine against Enterococcous faecalis in root canals; an in vitro study

BACKGROUND

Enterococcus faecalis has been widely used as a valuable microbiological pathogen for in vitro studies due to its ability to successfully colonize the root canal in a biofilm-like style, invade dentinal tubules, and resist endodontic treatment procedures.The aim of this study was to compare the bactericidal efficacy of photodynamic therapy (PDT), 2% chlorhexidine, 2.5% NaOCl, and combination of PDT and 2.5% NaOCl against E. faecalis.

MATERIALS AND METHODS

Sixty single-rooted teeth had their canals contaminated with E. faecalis in brain heart infusion broth and were incubated for 48 hours.The canals were then subjected to 2% chlorhexidine, 2.5% NaOCl, PDT (red light emitting diode 625 nm+ Toludine Blue) and PDT + 2.5% NaOCl. Controls consisted of no treatment (positive control) and without inoculation of bacterium (negative control). Following treatment, the canal contents were sampled with sterile paper points.The samples were dispersed in transport medium, serially diluted, and cultured on blood agar to determine the number of colony forming units (CFU). Data were analyzed by Mann-Whitney U test at 5% significance level. The significance level for all analyses was set at P <.05.

RESULTS

Combination of PDT and 2.5% NaOCl achieved maximum reduction in recovered viable bacteria, no viable bacteria was observed after treatment of PDT + 2.5% NaOCl.

CONCLUSION

Combination of PDT and 2.5% NaOCl simultaneously is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.

Candida auris Dry Surface Biofilm (DSB) for Disinfectant Efficacy Testing

Candida auris is an emerging pathogen that needs to be controlled effectively due to its association with a high mortality rate. The presence of biofilms on dry surfaces has been shown to be widespread in healthcare settings. We produced a C. auris dry surface biofilm (DSB) on stainless steel surfaces following sequential hydration and desiccation cycles for 12 days. The ASTM2967-15 was used to measure the reduction in viability of 12 commercially wipe-based disinfectants and sodium hypochlorite (1000 ppm) against C. auris DSB. We also evaluated C. auris transferability and biofilm regrowth post-treatment. A peracetic acid (3500 ppm) product and two chlorine-based products (1000 ppm available chlorine) were successful in reducing C. auris viability and delaying DSB regrowth. However, 50% of the products tested failed to decrease C. auris viability, 58% failed to prevent its transferability, and 75% did not delay biofilm regrowth. Using three different parameters to measure product efficacy provided a practical evaluation of product effectiveness against C. auris DSB. Although log10 reduction in viability is traditionally measured, transferability is an important factor to consider from an infection control and prevention point of view as it allows for determination of whether the surface is safe to touch by patients and hospital staff post-treatment.

Penetration depth of irrigants into root dentine after sonic, ultrasonic and photoacoustic activation

AIM

To compare penetration depths of endodontic irrigants into the dentinal tubules of extracted teeth when using several activation methods.

METHODOLOGY

The root canals of 90 extracted human teeth were prepared to size 40, .06 taper. The straight and round-shaped root canals were distributed randomly into six groups, and final irrigation was performed with EDTA and sodium hypochlorite as follows: (I) manual dynamic activation, (II) Ultrasonic, (III) Sonic, (IV) PIPS (photon-induced photoacoustic streaming, (V) SWEEPS (shock-wave enhanced emission photoacoustic streaming) and (0) control without final irrigation or activation. Subsequently, methylene blue was inserted into the canals and activated according to the groups (I-V). Teeth were sectioned horizontally, imaged under a light microscope, and dye penetration depths were measured in six sections per tooth and 24 points on a virtual clock-face per section. Data were analysed statistically by nonparametric tests for whole teeth and separately for coronal, middle and apical thirds.

RESULTS

Penetration of dye into the dentinal tubules was lowest for the controls. Median penetration depths amounted to 700-900 μm for groups I-V with differences in the apical thirds between group I and the other test groups. Minimum penetration depths were significantly greater for PIPS in the apical thirds (P ≤ 0.046).

CONCLUSIONS

Greater penetration depths occurred in the apical thirds for ultrasonic, sonic and laser-induced activation compared to manual dynamic activation. PIPS was associated with deeper penetration of irrigants. The novel SWEEPS mode did not increase irrigant penetration.

Evaluation of 4 Different Irrigating Systems for Apical Extrusion of Sodium Hypochlorite

INTRODUCTION

The aim of this study was to evaluate NaOCl apical extrusion by using negative apical pressure (EndoVac), sonic agitation (EndoActivator), side-vented needle (Max-i-Probe), and photon induced photoacoustic streaming (PIPS 10 mJ and PIPS 20 mJ) laser irrigation in an in vitro gel model.

METHODS

Extracted mandibular and maxillary central incisors (n = 18) were prepared to size 35/.04 and 55/.04, respectively. Teeth were mounted in transparent containers with clear acrylic and suspended in a color-changing pH-sensitive gel, creating a closed system. By using a crossover design, each tooth was sequentially irrigated by using 6% NaOCl with each device following manufacturers' recommendations. Each tooth served as its own control. Pre-irrigation and post-irrigation buccal and proximal view photographs served to measure the longest distance of extrusion and were analyzed with ImageJ software. Mean results were analyzed by using Kruskal-Wallis and Dunn post hoc test (P < .05).

RESULTS

There were no significant differences between EndoVac, EndoActivator, and the passive extrusion groups. The EndoVac and EndoActivator groups produced significantly less extrusion than PIPS irrigation. Max-i-Probe extrusion results were more variable than those of EndoActivator but had no significant difference. Across all irrigation systems, there were no significant differences with respect to apical preparation size.

CONCLUSIONS

Under the in vitro conditions of this study, no difference was found between the 10 mJ and 20 mJ PIPS laser groups. EndoVac demonstrated significantly less potential for apical extrusion than PIPS and Max-i-Probe, whereas apical preparation size did not significantly affect extrusion of irrigant. The potential for apical extrusion of endodontic irrigants should be a consideration when selecting a system for final irrigation.

Use of bleach baths for the treatment of infected atopic eczema

Atopic eczema is one of the most common skin disorders in young children and also affects adults. Staphylococcus aureus infection is the most frequent complication of atopic eczema and is involved in the worsening of the disease. Antibiotic therapy against S. aureus has been an important component of treatment for atopic eczema but there are concerns about antibiotic overuse and increasing bacterial resistance. This has led some clinicians to recommend the use of homemade remedies such as bleach baths as an adjunctive treatment for patients with infected atopic eczema, despite the fact that there have been few published studies in this area. Balancing safety concerns with efficacious treatment is of particular importance in the paediatric population. This review discusses the historical use of bleach in medicine as well as its recent use for atopic eczema. Further, the chemistry and safety of bleach as well as alternative therapies are examined.

Effect of subinhibitory concentrations of four commonly used biocides on the conjugative transfer of Tn916 in Bacillus subtilis

Objectives

Large amounts of biocides are used to reduce and control bacterial growth in the healthcare sector, food production and agriculture. This work explores the effect of subinhibitory concentrations of four commonly used biocides (ethanol, hydrogen peroxide, chlorhexidine digluconate and sodium hypochlorite) on the conjugative transposition of the mobile genetic element Tn916.

Methods

Conjugation assays were carried out between Bacillus subtilis strains. The donor containing Tn916 was pre-exposed to subinhibitory concentrations of each biocide for a defined length of time, which was determined by an analysis of the transcriptional response of the promoter upstream of tet(M) using β-glucuronidase reporter assays.

Results

Ethanol significantly (P = 0.01) increased the transfer of Tn916 by 5-fold, whereas hydrogen peroxide, chlorhexidine digluconate and sodium hypochlorite did not significantly affect the transfer frequency.

Conclusions

These results suggest that exposure to subinhibitory concentrations of ethanol may induce the transfer of Tn916-like elements and any resistance genes they contain.

Comparison of different dentin pretreatment protocols on the bond strength of glass fiber post using self-etching adhesive

INTRODUCTION

This study compared the influence of different irrigants with and without ultrasound or laser irradiation on the bond strength of glass fiber posts using a self-etching adhesive in a supplementary dentin pretreatment.

METHODS

Ninety bovine incisor roots were divided into 3 groups according to the irrigant tested: 2% chlorhexidine (CHX) (n = 30); 2.5% sodium hypochlorite (NaOCl) (n = 30), and saline solution (control) (n = 30). Each group was randomly divided into 3 subgroups according to the supplementary dentin pretreatment: ultrasound, Nd:YAG laser, and nonsupplemented (control). A self-etching adhesive system (Futurabond DC; VOCO GmbH, Cuxhaven, Germany) was used, and the glass fiber posts were cemented with dual-cure epoxy-based luting agent (Bifix QM, VOCO GmbH). All roots were sectioned transversely, and the push-out test was performed. Failure mode analysis was also evaluated.

RESULTS

Bond strength decreased significantly after the use of 2.5% NaOCl in all root thirds (P < .05). CHX showed no difference in the mean bond strength value compared with saline solution (P > .05). The supplementary dentin pretreatment using the Nd:YAG laser or ultrasound did not improve the bond strength values for both NaOCl and CHX (P > .05). Moreover, the apical third exhibited the lowest mean bond strength values (P < .05). Analysis indicated that the predominant failure mode was the mixed type.

CONCLUSIONS

Regardless of the irrigant used, the supplementary dentin pretreatment with ultrasound or laser irradiation showed no improvement in bond strength. Also, the use of NaOCl decreased the bond strength of glass fiber posts using a self-etching adhesive system, whereas CHX preserved it.

The antibacterial activity of sodium hypochlorite and chlorhexidine against Enterococcus faecalis: A review on agar diffusion and direct contact methods

Complete debridement and disinfection of the root canal system are fundamental requirements for successful endodontic treatment. Despite the morphological challenges of the internal root anatomy, root canal irrigants play an important role in the optimization of the root canal preparation, which is essentially a chemo-mechanical procedure. Enterococcus faecalis is one of the most resistant microorganisms that dominants the microbial ecosystem of persistent periradicular lesions in retreatment cases. For that reason, many in vitro and in vivo studies evaluated and compared the antibacterial activity of sodium hypochlorite and chlorhexidine at varying concentrations using different experimental models against this microorganism. However, many controversies with regard to the ideal irrigant and concentration do in fact exist. Hence, this review aims to discuss the antibacterial activity of these two main root canal irrigants against Enterococcus faecalis using the agar diffusion and direct contact methods and the possible modulating factors responsible for inconsistent findings among different studies. In addition, the disinfection potential of both chemical agents on gutta percha and Resilon cones are also discussed. The source of this review was conducted through an electronic literature search using PubMed database from December 1997 until December 2011, which analyze the related laboratory investigations of both irrigants, published in major endodontic journals.

Survey of root canal irrigating solutions used in dental practices within Germany

AIM

Irrigant usage information in relation to years of professional experience was collected from general dentists in different German federal states by means of a questionnaire.

METHODOLOGY

A short survey concerning endodontic treatment and use of irrigants was mailed to 4240 dentists or delivered to 3720 dental offices as an extra page in a journal in eight German states. Detailed information concerning the most frequently used irrigants, their concentrations, the spectrum of disinfectants used in root canal treatment concepts for vital and nonvital pulps, main topics of continuing education as well as years of professional experience was collected. The statistical analysis of differences found amongst the dentists in relation to professional experience or federal state was performed using the chi-square test.

RESULTS

Of a total of 7960 invitations, 1630 replies were evaluated (response rate 20.5%). The majority of the dentists (57.3%) had >20 years of professional experience, 23% had >30 years. Dentists with long-standing professional experience (20-30 years) used H2 O2 significantly more often than dentists with less experience (P < 0.001), and of the older colleagues (>30 years of professional experience), 14.6% never used NaOCl, whilst the younger colleagues almost always used it (P < 0.001). Differences were also found for the usage of irrigants amongst dentists from the various German states.

CONCLUSIONS

Whilst NaOCl was used in almost all states, regional differences were found regarding the choice of additional irrigants, which were mainly determined by the irrigation protocols taught at different universities.

Combined Antibacterial Effect of Sodium Hypochlorite and Root Canal Sealers against Enterococcus faecalis Biofilms in Dentin Canals

INTRODUCTION

The present study aimed to evaluate the antibacterial effect of the combined use of sodium hypochlorite (NaOCl) and root canal sealers on Enterococcus faecalis biofilms using a dentin infection model.

METHODS

Cells of E. faecalis were introduced into the dentinal tubules by centrifugation and incubated in brain-heart infusion for 3 weeks. The biofilms in dentin were first subjected to 5% NaOCl or sterile water for 10 minutes followed by an equal thickness of AH Plus (Dentsply International Inc, York, PA), Endosequence BC Sealer (Brasseler USA, Savannah, GA), or MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brazil) placed on the root canal wall of the dentin specimens for 7, 30, and 60 days. Gutta-percha and water were used in a similar manner as controls. The proportions of dead and live bacteria inside the dentinal tubules were assessed by confocal laser scanning microscopy and viability staining.

RESULTS

The combined use of NaOCl and sealers (30 and 60 days) killed significantly more bacteria than NaOCl or sealers alone (P < .05). NaOCl + MTA Fillapex was the most effective antibacterial combination by killing 83% bacteria in dentin tubules in 60 days. Thirty and 60 days of exposure to the sealers resulted in significantly more dead bacteria in dentin biofilms than 7-day exposures (P < .05).

CONCLUSIONS

The placement of root canal sealer after NaOCl treatment enhanced antibacterial effects against E. faecalis in the dentinal tubules. Little additional effect was obtained after 30 days of exposure to sealers.

Irrigants for non-surgical root canal treatment in mature permanent teeth

BACKGROUND

Root canal treatment is carried out on teeth in which irreversible pulpitis has led to necrosis of the dental pulp. As a treatment option it is an alternative to dental extraction. Mechanical preparation and irrigation with antiseptic or antibacterial solutions destroys bacteria and cleans the infected root canal. Irrigants should be effective in deactivating bacteria in the entire root canal space without causing any adverse tissue reactions. Sodium hypochlorite (NaOCl) and chlorhexidine are commonly used but there is uncertainty as to which solution, concentration or combination is the most effective.

OBJECTIVES

To assess the effects of irrigants used in the non-surgical root canal treatment of mature permanent teeth.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 5 July 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 4), MEDLINE via Ovid (1950 to 5 July 2012), EMBASE via Ovid (1980 to 5 July 2012), LILACS via BIREME (1980 to 5 July 2012). There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

Randomised controlled trials in single or multi-rooted permanent teeth with pulpal or periapical pathology or both, which require root canal treatment. Irrigants either against each other or against inactive irrigant or placebo. Combinations of irrigants were allowed and if used in conjunction with EDTA (ethylenediaminetetra-acetic acid) or similar chelating agents.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias of included trials and extracted data.

MAIN RESULTS

We included 11 trials involving 851 participants with 879 teeth which had undergone root canal treatment and involved the use of irrigants. Two trials were assessed as being at low risk of bias, with six unclear and three high. Four trials compared sodium hypochlorite versus chlorhexidine, however, no primary outcomes and only one secondary outcome, bacterial growth cultures, was reported for two of these trials (20% and 50% of teeth in the control group had positive bacterial culture). The meta-analysis indicated no strong evidence of a difference in the existence of bacterial growth between the interventions (risk ratio 0.73; 95% confidence interval 0.34 to 1.56; P = 0.41). The seven remaining trials each compared different interventions and only two of these trials included useable data on the primary outcomes of swelling and pain. One trial compared sodium hypochlorite 5.25% alone versus sodium hypochlorite 5.25% combined with hydrogen peroxide 3%, and versus normal saline and reported pain at 3 to 14 days after the procedure. There was no evidence of a difference in pain between the three groups. The other trial compared sodium hypochlorite 5% versus sodium hypochlorite with 'proteolytic enzyme', and there was no evidence of a difference in swelling between the groups. Two further trials reported bacterial growth, and three trials failed to report any data which could be used in the review. None of the included trials reported any data on adverse effects nor radiological changes in periapical radiolucency.

AUTHORS' CONCLUSIONS

Although root canal irrigants such as sodium hypochlorite and chlorhexidine appear to be effective at reducing bacterial cultures when compared to saline, most of the studies included in this review failed to adequately report these clinically important and potentially patient-relevant outcomes. There is currently insufficient reliable evidence showing the superiority of any one individual irrigant. The strength and reliability of the supporting evidence was variable and clinicians should be aware that changes in bacterial counts or pain in the early postoperative period may not be accurate indicators of long-term success. Future trials should report both clinician-relevant and patient-preferred outcomes at clearly defined perioperative, as well as long-term, time points.

Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

Aim:

To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods.

Materials and Methods:

Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (CHX), neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, and diode laser. The effect of disinfection methods was assessed by LIVE/DEAD BacLight stain under the confocal laser scanning microscopy to determine the “zone of dead bacteria” (ZDB). Mean values were calculated for ZDB and the difference between groups was established.

Results:

Penetration of E. faecalis was seen to a depth of >1000 μm. Viable bacteria were detected with NS irrigation. NaOCl and CHX showed partial ZDB. When the root canals were disinfected with Nd: YAG and diode lasers, no viable bacteria were found.

Conclusion:

E. faecalis has the ability to colonize inside dentinal tubules to a depth of >1000 μm. In contrast to conventional irrigants, both Nd: YAG and diode lasers were effective in eliminating the vitality of E. faecalis. NS, NaOCl, and CHX showed viable bacteria remaining in dentinal tubules.

Wound Antiseptics and European Guidelines for Antiseptic Application in Wound Treatment

Issues arising in wound healing are very common, and chronic wound infections affect approximately 1.5% of the population. The main substances used in wound washing, cleansing and treatment are antiseptics. Today, there are many compounds with a known antiseptic activity. Older antiseptics (e.g., boric acid, ethacridine lactate, potassium permanganate, hydrogen peroxide, iodoform, iodine and dyes) are not recommended for wound treatment due to a number of disadvantages. According to the newest guidelines of the Polish Society for Wound Treatment and the German Consensus on Wound Antisepsis, only the following antiseptics should be taken into account for wound treatment: octenidine (OCT), polihexanide (PHMB), povidone-iodine (PVP-I), sodium hypochlorite (NaOCl) and nanosilver. This article provides an overview of the five antiseptics mentioned above, their chemical properties, wound applications, side effects and safety.

Comparison of antimicrobial efficacy of propolis, Morinda citrifolia, Azadirachta indica (Neem) and 5% sodium hypochlorite on Candida albicans biofilm formed on tooth substrate: An in-vitro study

INTRODUCTION

Endodontic infections are polymicrobial in nature. Candida albicans is the most common fungus isolated from failed endodontic cases. The constant increase in antibiotic resistant strains and side-effects caused by synthetic drugs has prompted researchers to look for herbal alternatives such as propolis, Morinda citrifolia and Azadirachta indica (Neem) etc., since, the gold standard for irrigation, i.e., sodium hypochlorite has many disadvantages.

MATERIALS AND METHODS

Extracted human mandibular premolars were biomechanically prepared, vertically sectioned, placed in tissue culture wells exposing the root canal surface to C. albicans grown on Sabouraud Dextrose Agar to form a biofilm. At the end of 2 days, all groups were treated with test solutions and control for 10 min and evaluated for Candida growth and number of colony forming units. The readings were subjected to statistical analysis using analysis of variance and post hoc Tukey tests.

RESULTS

Sodium hypochlorite and propolis groups exhibited highest antimicrobial efficacy against C. albicans with no statistically significant difference. It was followed by the A. indica (Neem) group. M. citrifolia had limited antifungal action followed by the negative control group of saline.

CONCLUSION

According to the results of this study, propolis can be used as an effective antifungal agent similar to that of sodium hypochlorite, although long-term in vivo studies are warranted.

Effects of concentration of sodium hypochlorite as an endodontic irrigant on the mechanical and structural properties of root dentine: A laboratory study

AIM

The use of high-concentration sodium hypochlorite (NaOCl) as an endodontic irrigant remains controversial because of its potential impact on the fracture strength of endodontically-treated teeth. This study evaluated the effects of using different NaOCl concentrations, with 2-min-ethylenediaminetetraacetic acid (EDTA) as the final active irrigant, on the biomechanical and structural properties of root dentine.

METHODOLOGY

A new test method, which is more clinically relevant, was utilized to calculate the fracture strength of root dentine. Bovine incisors were used to obtain root dentine discs. The root canals were enlarged to mean diameter of 2.90 mm with a taper of 0.06. The resulting discs were divided into 5 groups (n=20) and treated with different concentrations of NaOCl (5.25%, 2.5%, and 1.3%) for 30 min plus 17% EDTA for 2 min. The discs were then loaded to fracture by a steel rod with the same taper through the central hole. The fractured specimens were examined by scanning electron microscopy to evaluate changes in the dimensions of the remaining intertubular dentine and the tubular radius. Micro-hardness was also measured with a Knoop diamond indenter along a radius to determine the depth of dentine eroded by the irrigation. Results were analyzed by one-way ANOVA and the Tukey test. The level of significance was set at α = 0.05.

RESULTS

The damage by NaOCl increased with its concentration. 5.25% NaOCl greatly reduced the fracture strength of root dentine from 172.10±30.13 MPa to 114.58±26.74 MPa. The corresponding reduction in micro-hardness at the root canal wall was 34.1%. The damages reached a depth of up to 400 μm (p < 0.05). Structural changes involved degradation of the intratubular wall leading to enlarged dentinal tubules and the loss of intertubular dentine. Changes in the microstructural parameters showed positive linear relationships with the fracture strength.

CONCLUSIONS

With the adjunctive use of EDTA, NaOCl caused destruction to the intratubular surface near the root canal and, consequently, reduced the root dentine's mechanical strength. The higher the concentration of NaOCl, the greater the effect. Therefore, endodontists should avoid using overly high concentration of NaOCl for irrigation to prevent potential root fracture in endodontically-treated teeth.

Effects of Dentin Debris on the Antimicrobial Properties of Sodium Hypochlorite and Etidronic Acid

INTRODUCTION

The purpose of this study was to determine the influence of dentin powder on the concentration, pH, and antimicrobial activity of sodium hypochlorite (NaOCl) alone and combined with etidronic acid (HEBP).

METHODS

Biofilms of Enterococcus faecalis were grown on the surface of dentin blocks for 5 days and then exposed to 1% and 2.5% NaOCl alone or combined with 9% HEBP for 3 minutes in the absence and presence of dentin powder. The biovolumes of the biofilm were measured using confocal microscopy and the live/dead technique. The available chlorine and pH of the solutions were also measured. Nonparametric tests were used to determine statistical differences (P < .05).

RESULTS

The presence of dentin powder resulted in a reduction of the free available chlorine and pH in all the irrigating solutions; 1% NaOCl lost its antimicrobial activity completely in the presence of dentin powder. The antimicrobial activity was significantly reduced in the 2.5% NaOCl and 1% NaOCl/HEBP groups, and it was not affected in the 2.5% NaOCl/HEBP group.

CONCLUSIONS

The presence of dentin powder significantly decreased the available chlorine and antimicrobial activity of 1% NaOCl, 2.5% NaOCl, and 1% NaOCl/HEBP irrigating solutions. The antimicrobial activity of 2.5% NaOCl/HEBP was not affected by the dentin powder after a 3-minute contact time against E. faecalis biofilms.