Influence of the Use of Irrigation Solution Inhibitors in Improving Dentine Adhesion: A Systematic Review and Meta-Analysis

INTRODUCTION

This systematic review examined the effect of neutralizing agents on bond strength after irrigation with sodium hypochlorite and their existing protocols in literature.

METHODS

This present study adhered to the PRISMA guidelines and was registered at PROSPERO. Five electronic databases were searched (sept-2020/jan-2021) in English, Spanish, and Portuguese, without any restrictions on publication date. Cases reports, editorials and literature reviews were not included. The risk of bias was assessed using the Cochrane Collaboration tool. From the initial 7,147 studies, 2,745 were removed as duplicates and 4,382 were excluded after a title/abstract screen.

RESULTS

Seventeen in vitro studies were included. The results showed that the higher the concentration of sodium hypochlorite, the lower the bond strength at dentine/restoration interface (p⟨0.01). Among the studies, sodium ascorbate was the most widely used neutralizer and showed the most significant results in increasing bond strength (p⟨0.01). The bond strength values were found to increase with longer application time of the neutralizing substances (p⟨0.01).

CONCLUSIONS

The use of sodium ascorbate as a neutralizing agent can reverse the negative effects of the sodium hypochlorite and improve the bond strength between dentine and resin cement, however, it isn't possible to determine the best protocol for use.

Effect of sodium hypochlorite temperature and concentration on the fracture resistance of root dentin

BACKGROUND

Sodium hypochlorite (NaOCl) is the most efficient root canal irrigant to date. The aim of this study was to compare the effect of NaOCl used at different temperatures and concentrations on the compressive strength of root dentin.

MATERIALS AND METHODS

Seventy-two extracted human single-canaled straight roots of comparable size and length were selected and randomly divided into six groups (n = 12): Group (A) served as a control with unprepared canals. The other groups were instrumented with rotary ProTaper Universal files up to size F3. Group (B) was irrigated with 1% NaOCl at room temperature, Group (C) with 1% NaOCl heated to 70 °C, Group (D) with 5.25% NaOCl at room temperature, and Group (E) with 5.25% NaOCl heated to 70 °C. Saline was used in Group (F). The roots were sectioned into 2-mm-thick disks that underwent compression testing using a universal testing machine. Data were analyzed using one-way ANOVA and post hoc Tukey tests. The significance level was set at p ≤ 0.05.

RESULTS

A total of 255 disks were tested. The control group showed the highest compressive strength (p = 0.0112). However, this did not differ significantly from that of heated (p = 0.259) or unheated (p = 0.548) 1% NaOCl. There were no statistically significant differences between the groups of instrumented teeth.

CONCLUSION

Within the conditions of this study, irrigation with NaOCl at different concentrations and temperatures during root canal preparation did not affect the compressive strength of root dentin.

CLINICAL RELEVANCE

This study demonstrates that the use of NaOCl as a root canal irrigant is not associated with a clinically relevant decrease in root compressive strength, especially when compared to saline.

Sodium Hypochlorite-induced Facial Hematoma Following Root Canal Treatment

This case report highlights a rare complication of root canal treatment involving the inadvertent extrusion of sodium hypochlorite solution, resulting in a sodium hypochlorite-induced facial hematoma. A 44-year-old female patient presented significant right hemifacial swelling and ecchymosis following root canal therapy. Computed tomography imaging confirmed a hematoma involving the facial region without active signs of bleeding. Sodium hypochlorite, a potent cytotoxic agent commonly used in root canal procedures, was identified as the causative agent. Treatment consisted of prednisone, antibiotics, and NSAIDs, resulting in gradual improvement over a month. The cytotoxic properties of sodium hypochlorite, its variable concentrations, and risk factors associated with facial hematomas are discussed. It is essential to emphasize the rarity of such hematomas and highlight the need for precise technique, vigilant monitoring, and interdisciplinary collaboration to mitigate risks and prioritize patient safety.

Comparative Evaluation of Apically Extruded Debris During Root Canal Preparation Using Three Different File Systems Applied Under 2.5% Sodium Hypochlorite or 2% CHX Irrigation

The chemomechanical cleaning of the root canal system is performed using manual and rotary files. This study aimed to compare the effect of ProTaper, Reciproc and HyFlex rotary files considering 2.5% sodium hypochlorite and 2% chlorhexidine (CHX) as irrigating solutions on apical extrusion of intracanal debris. Single-canal mandibular premolars (N=165) were evaluated. The teeth were divided into 6 experimental groups (N=25) for root canal instrumentation using 3 file systems, (Reciproc, HyFlex and ProTaper) and two irrigation solutions, namely 2.5% sodium hypochlorite or 2% CHX. Fifteen teeth were also assigned into three control groups (n=5) with saline as irrigation solution. Eppendorf tubes were weighed and the teeth were placed inside. The canals were instrumented and the tubes weighed to determine the dry weight of extruded debris. Data were analyzed using one-way ANOVA and Bonferroni test (α=0.05). The mean amount of extruded debris using the sodium hypochlorite solution was significantly higher than other irrigating solutions (p⟨0.001). The mean amount of extruded debris using the Reciproc file system was significantly higher compared to ProTaper and HyFlex (p⟨0.001). The use of the sodium hypochlorite solution, single-file systems and reciprocal movement are associated with higher debris extrusion and might be associated with higher risk of postoperative pain.

A comparative clinico-radiographic analysis of regenerative endodontic procedure on immature necrotic permanent teeth using blood clot and PRF as scaffold: A retrospective study

Objectives

To evaluate the clinical and radiographic success rate of blood clot and platelet rich fibrin (PRF) as a scaffold system in regenerative endodontic procedure in immature traumatized necrotic teeth..

Materials and methods

This retrospective study examined the records of 28 subjects with necrotic immature open apex due to trauma treated with blood clot or PRF as a scaffold in regenerative endodontic procedure. The disinfection was carried out with calcium hydroxide as an intra-canal medicament. The clinical outcome was recorded using a binary variable of presence or absence of pain and intra-oral swelling. The radiographic outcome was recorded for periapical healing using Ørstavik's Periapical Index and apical response using Chen and Chen index. Comparison of frequencies of categories of variables with groups was done using the chi-square test. The pairwise comparison of time intervals was done using Wilcoxon Signed Ranks Test.

Results

Intra-group comparison of pain and intra-oral swelling had highly significant (p = 0.000) results for both groups over a period of 12 months. Inter-group comparison for clinical outcomes was insignificant. For the radiographic outcome, there was a statistically non-significant difference for periapical healing and apical response for both intra-group and inter-group comparisons.

Conclusion

Both PRF and blood clot have a favourable outcome for a regenerative endodontic procedure with a disinfectant protocol using calcium hydroxide as intracanal medicament. Considering the cumbersome procedure involved in procuring PRF scaffold, especially in children, inducing bleeding can be considered a recommended method for a regenerative endodontic procedure.

Comparative Effects of Three Bleaching Techniques on Tooth Discoloration Caused by Tea

Objectives: This study aimed to investigate the impact of three different bleaching protocols on tooth discoloration caused by tea. Materials and Methods: Forty extracted sound premolars were cleaned, disinfected, and their initial color parameters were measured (T1). The teeth were then immersed in boiled tea solution for 24 hours, and their color was measured again (T2). The samples were divided into four groups of 10 teeth each. Group A was treated with an in-office bleaching gel followed by 30 seconds of light curing. Groups B, C, and D were respectively treated with 0.24M oxalic acid followed by bleaching gel, 5.25% sodium hypochlorite followed by bleaching gel, and a combination of 0.24M oxalic acid, 5.25% sodium hypochlorite, and bleaching gel. The color was measured once more after the interventions (T3). Data were analyzed using two-way repeated measures ANOVA, paired sample t-test, and Tukey's test. Results: The mean color change (∆E2) between T2 and T3 was significantly higher in group D compared to group A (P<0.05). However, there was no significant difference in color change between groups A, B, and C. Additionally, there was no significant difference in color change between groups B, C, and D. The groups also showed significant differences in ∆L (P=0.007), with the only significant difference found between groups B and C (P=0.001). Conclusion: The combined use of sodium hypochlorite and oxalic acid followed by in-office bleaching gel is more effective than bleaching alone in correcting tooth discoloration caused by tea. This protocol can further reduce yellow coloration.

Effect of Immersion in Disinfectants on Cyclic Fatigue Resistance of Nickel-Titanium Instruments: An in Vitro Study

Objectives: The current study aimed to assess the cyclic fatigue resistance of two nickel-titanium (NiTi) rotary files after immersion in 5% sodium hypochlorite (NaOCl) and Deconex. Materials and Methods: In this in vitro study, 90 new M3 Pro Gold size 25.06 and size F2 SP1 files were tested. Forty-five files of the same brand were randomly distributed into three groups (n=15) and submitted to the following immersion protocol for 5 minutes at room temperature: no immersion (control group), immersion in 5% NaOCl, and immersion in Deconex. The cyclic fatigue resistance of the files was then measured in a custom-made tester. Two-way ANOVA was applied to compare the cyclic fatigue resistance of SP1 and M3 NiTi rotary files based on the type of disinfectant solution. Post-hoc LSD test was used for pairwise comparisons and P<0.05 was considered significant. Results: Two-way ANOVA indicated a significant difference in the mean cyclic fatigue resistance of M3 and SP1 NiTi rotary files. The M3 files immersed in NaOCL displayed the lowest and the SP1 files immersed in Deconex showed the maximum cyclic fatigue resistance. The effect of type of disinfectant solution (P<0.001) and type of NiTi file (P<0.001) on cyclic fatigue resistance was statistically significant. Conclusion: The cyclic fatigue resistance of NiTi rotary instruments can be affected by immersion in disinfectants, and the specific type of file and disinfectant used will ultimately determine the extent of this impact.

Antimicrobial Efficacy of Different Irrigant Solutions Using a Novel Biofilm Model: An In Vitro Confocal Laser Scanning Microscopy Experiment

AIM

To determine the ability of different irrigation solutions to biomechanically remove Enterococcus faecalis biofilm from a novel artificial root canal model during chemomechanical preparation.

METHODS

High resolution micro-computer-tomography scans of a mandibular molar's mesial root were used to produce 50 identical 3D-printed resin root canal models. These were cultured with E.faecalis over seven days to generate biofilm and subjected to chemomechanical preparation using: saline; 17% ethylenediaminetetraacetic acid (EDTA) or 2% sodium hypochlorite (NaOCl) alongside positive/negative controls (n = 10). Canals were prepared to 40/.06 taper, with 1 mL irrigation between instruments, followed by 5 mL penultimate rinse, 30 s ultrasonic activation and 5 mL final rinse. Residual biofilm volume (pixels) was determined following immunofluorescent staining and confocal-laser-scanning-microscopy imaging. Statistical comparisons were made using Kruskal-Wallis with post-hoc Dunn's tests (α ⟨0.05).

RESULTS

In all canal thirds, the greatest biofilm removal was observed with NaOCl, followed by EDTA and saline. The latter had significantly higher E.faecalis counts than NaOCl and EDTA (P ⟨0.01). However, no statistical differences were found between EDTA and NaOCl or saline and positive controls (P ⟩0.05).

CONCLUSIONS

Within limitations of this model, 17% EDTA was found to be as effective as 2% NaOCl at eradicating E.faecalis biofilm following chemomechanical preparation. Further investigations with multi-species biofilms are encouraged.

The Impact of Different Irrigation Regimens on the Chemical Structure and Cleanliness of Root Canal Dentin

Introduction

This in vitro study aimed to evaluate the effect of different irrigation regimens on the chemical composition and cleanliness of root canal dentin.

Materials and Methods

Forty-eight extracted single-rooted permanent human teeth were collected. Root canals were instrumented using step-back technique up to master apical file size 60. Samples were divided into 3 groups (n=16) based on the type of the irrigant used. The irrigation solutions were 5.25% sodium hypochlorite, 2% chlorhexidine gluconate, and saline solution as a control. Root canal cleanliness was assessed using stereomicroscope and scanning electron microscope. Scanning electron microscope energy dispersive X-ray was used for the inorganic analysis. Fourier transform infrared spectrometer was used for the organic analysis. One-way analysis of variance (ANOVA) and multiple comparison post hoc test were used for comparison between the three groups.

Results

The highest mean percentage of remaining debris was in saline group followed by chlorhexidine gluconate group. Sodium hypochlorite group showed the lowest mean value of remaining debris. Furthermore, our results showed that canal irrigation with sodium hypochlorite affected the chemical structure of root canal dentin more than chlorhexidine gluconate.

Conclusions

Based on the results, 5.25% sodium hypochlorite emerges as the preferred irrigant for root canal treatment. This research sheds light on the significance of irrigation regimens in endodontics and emphasizes the need for careful consideration of irrigant selection in clinical practice.

Postoperative Endodontic Pain after Treatment Using XP-endo Finisher: A Randomized Clinical Trial

Introduction

This randomized clinical trial aimed to determine whether the XP-endo finisher combined with or without foraminal enlargement has any significant effect on the incidence and intensity of postoperative pain in necrotic pulps.

Materials and Methods

Clinical pain levels were measured after 6, 12, 24, 48, and 72 hours and at 7 postoperative days. All treatments were performed by an endodontist in a single visit. One hundred and twenty patients were included. All patients had a single tooth treated. The patients were divided into four groups: No FE (None Foraminal Enlargement) (n=30), FE (Foraminal Enlargement) (n=30), No FE+XPF (None Foraminal Enlargement+XP-endo Finisher) (n=30) and XPF+FE (XP-endo Finisher and Foraminal Enlargement) (n=30). The canals were irrigated with sodium hypochlorite, shaped using WaveOne Gold Medium file, and then filled by using a matching single cone and AH-Plus sealer. The cavity was filled using glass ionomer cement. Pain intensity was assessed using the visual analog scale. The data were analyzed with the ANOVA and Games-Howell test. The significance level was 5%.

Results

The XPF+FE group experienced a higher level of pain, being classified on the visual analog scale as moderate for 48 postoperative hours and mild for 7 postoperative days (P<0.05). In the other groups, the pain was mild, only with different time intervals (P>0.05).

Conclusions

Foraminal enlargement associated with XP-endo Finisher may cause moderate postoperative pain.

Influence of sodium hypochlorite concentration on cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS): A visualization study

PURPOSE

The aim of the present study was to visualize and compare the cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS) using sodium hypochlorite (NaOCl) with different concentrations as irrigant.

METHODS

Forty artificial root canals were prepared using MTWO Niti file up to size #25/.06. The canals were randomly divided into four groups (n = 10/group). High-speed camera was used to visualize and compare the cavitation effect induced by PIPS in the artificial root canals containing saline or NaOCl. Fluid velocity and Reynolds number of saline, 1%-, 2.5%- and 5.25% NaOCl irrigants induced by PIPS in the apical region were calculated using TEMA 2D software while the fluid motions were recorded.

RESULTS

Visualization profile revealed that NaOCl presented a stronger cavitation effect and fluid dynamics than saline during PIPS activation. In the apical region, 1% NaOCl group presented the highest average velocity of 3.868 m/s, followed by 2.5% NaOCl group (3.685 m/s), 5.25% NaOCl group (2.353 m/s) and saline group (1.268 m/s), corresponding to Reynolds number of 1653.173, 1572.196, 995.503 and 477.692. Statistically higher fluid velocity was calculated in 1% and 2.5% NaOCl groups compared to saline group, respectively (p < 0.05).

CONCLUSIONS

The application of NaOCl and its concentration significantly influence the cavitation effect and fluid dynamics during PIPS activation. 1% and 2.5% NaOCl groups presented a more violent fluid motion in the apical region when activated by PIPS.

In Vitro Activity of Superoxide Water on Viability of Enterococcus faecalis Biofilm on Root Canal Wall

Introduction

The aim of this study was to compare the effect of root canal irrigation with superoxidized water and sodium hypochlorite on elimination of Enterococcus faecalis biofilm from the root canal walls.

Methods and Materials

In this experimental study, a total of 32 extracted human central incisors were used. The crowns of all teeth were cut to length of 16 mm. After cleaning and shaping, then the specimens were sterilized in autoclave and then divided into four groups (n=8) as following: group 1 (positive control, root canal irrigation with normal saline), group 2 (negative control without biofilm), group 3 (root canal irrigation with sodium hypochlorite) and group 4 (root canal irrigation with superoxidized water). The bacterial suspension was inserted to root canals of teeth except for negative control group in order to form a microbial biofilm in incubator for 2 weeks. Then all the samples received root canal irrigation for 5 min based on their allocation. At the end, colony forming unit (CFU) was evaluated and biofilm formation and thickness was detected with scanning electron microscopy. The Kruskal Wallis and Dunn's tests were done for biofilm thickness and CFU, respectively with the level of significance set at 0.05.

Results

In negative control group no biofilm formation and CFU was present. The CFU counts and biofilm thickness were significantly different between the experimental groups (P=0.001) and both parameters were less in samples with hypochlorite irrigation compared to positive control (52.56±5.82 µm for biofilm thickness and 1.2×10⁷ CFU) and samples irrigated with superoxidized water (2.92±1.76 µm for biofilm thickness and 5.4×10⁴ CFU).

Conclusion

Based on this in vitro study reduction in biofilm thickness and CFU/mL was 100% for sodium hypochlorite and for superoxidized water was 98% and 90% for reduction in biofilm thickness and CFU/mL, respectively.

Smear Layer Removal from the Apical Third Using the Er,Cr:YSGG Photon-induced Photoacoustic Streaming

Introduction

The purpose was to study the influence of Erbium,Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser at short pulse duration on smear layer removal from apical root third.

Materials and Methods

Twenty-four single-rooted mandibular premolars were used. The roots length was cut to 14 mm and instrumented using the Protaper Gold system to size 40/0.06. The samples were divided into four groups (n=6) as follows: (A) conventional irrigation with 5 mL of 17% Ethylenediaminetetraacetic acid ( EDTA), (B) passive ultrasonic irrigation with 5mL of 17% EDTA, (C) Er,Cr:YSGG induced photoacoustic streaming (PIPS) with 5 mL of 17% EDTA and (D)Er,Cr: YSGG induced PIPS with 5 mL of 5.25% sodium hypochlorite (NaOCl). After final irrigation with normal saline and drying, the roots were painted with nail varnish externally, and 2%methylene blue dye was injected into the canal. The tooth split horizontally at the fourth millimetres. The picture was taken by a professional Digital SLR camera. The dye penetration was measured using analytical software (measure picture CAD-KAS Kessler Germany). Dunnett's test was used to compare control group against experimental groups.

Results

After the statistical test, the highest mean percentage was presented in the laser group with 17% EDTA (Group C=85.9804) followed by the laser group with 5.25% NaOCl (Group D=69.7817) and ultrasonic group (Group B=34.5453) respectively and the lowest mean percentage was in the control group (Group A=20.7969).

Conclusion

Based on this in vitro study, PIPS technique using Er,Cr:YSGG pulse laser (0.5 W,5 Hz, air and water off) at short pulse duration and 17% EDTA proved effectively in smear layer removal, while the PIPS proved an acceptable result when the laser is used alone assisted by NaOCl.

Effect of Sodium Thiosulfate on Interfacial Adaptation and Penetration of an Epoxy Resin-Based Root Canal Sealer

Introduction

Our study evaluated the impact of sodium thiosulfate (ST) irrigation, subsequent to sodium hypochlorite (NaOCl) and just before root canal filling, on the filling quality (interfacial adaptation and penetration segment) of an epoxy resin-based root canal sealer.

Methods and Materials

Twenty single-rooted human teeth were prepared with the ProTaper system. The specimens were then divided into the following groups: 5.25% NaOCl irrigation (NaOCl group) and 5.25% NaOCl irrigation+0.5% sodium thiosulfate (NaOCl+ST group). The root canals were filled using single-cone technique with ProTaper F3 cones and AH-Plus sealer, labeled with rhodamine B dye to allow analysis under a confocal laser scanning microscopy (CLSM). All samples were sectioned at 2, 4, and 6 mm from the apex and prepared for CLSM analysis. The percentage of voids, gaps and dentinal sealer penetration segment of the canal were calculated at the apical, middle and coronal thirds. The non-parametric Mann-Whitney statistical test was used at 5% significance level.

Results

Higher percentage of gaps and voids were observed at all root thirds of the NaOCl group when compared to the NaOCl+ST group (P<0.05). There was a significant increase in the penetration segment of NaOCl+ST group at the coronal and middle root third when compared to the NaOCl group (P<0.05).

Conclusion

Our in vitro results showed that the use of ST as an antioxidant agent after NaOCl irrigation promoted a better interfacial adaptation and penetration of epoxy resin-based root canal fillings.

Comparative evaluation of various herbal and synthetic solutions on disinfection of guttapercha: An in vitro study

Background

Although gutta-percha cones are usually supplied in aseptic packages, once opened and used, they may be contaminated. Chair side disinfection of these cones is important and critical for success of endodontic therapy. Gutta-percha being heat labile, chemical disinfection is the only viable alternative for the sterilization of these cones.

Aim

The aim of the study was to evaluate an effective method of disinfection of gutta-percha cones using various herbal and chemical solutions after intentional contamination with Staphylococcus aureus and Enterococcus faecalis.

Materials and Methods

150 gutta-percha cones were selected for the study. Based on the contaminants used, 140 gutta-percha cones were divided into 2 groups: Group A and Group B with 70 cones in each group and the remaining 10 cones (Group VIII) which were uncontaminated served as negative control. The cones from Group A were contaminated with Staphylococcus aureus (S. aureus) and Group B were contaminated with Enterococcus faecalis (E. faecalis). The contaminated cones from both groups were subdivided into 7 groups with 10 cones in each group. Group I cones were disinfected with Q Mix 2 in 1, Group II with 3% sodium hypochlorite, Group III with chitosan, Group IV with aloe vera juice, Group V with amla juice, and Group VI with pancha tulsi. Group VII consisted of gutta-percha cones without any disinfection in both Group A and Group B which served as positive control. The disinfection time was 1 min. All the cones were then incubated in thioglycollate media for 7 days. The thioglycollate media was subcultured and colony forming units were counted. The data were analyzed by one-way ANOVA and post-hoc Tukey tests using SPSS 17.0 software.

Results

There was a statistically significant difference present in the mean colony forming units among all the groups (P < 0.05).

Conclusion

Pancha Tulsi and Q Mix 2 in 1 possessed superior antibacterial activity when compared to other experimental solutions.

The Effects of Sodium Hypochlorite on Organic Matters: Influences of Concentration, Renewal Frequency and Contact Area

Introduction

Sodium hypochlorite (NaOCl) reacts mainly with proteins and its effectiveness depends on the substances chemical reactivity. It has been reported that volume, concentration, renewal, time, temperature and contact area affect the diffusion of NaOCl in the root canal. However, the relationship between some of these factors is not clear. The purpose of this study was to test the effect of volume, contact area, concentration and renewal frequency of 2.5% and 9.8% NaOCl solutions on their organic matter dissolving-capacity.

Methods and Materials

Pieces of gelatine (18% w/v) with standardized weight, form and structure were either fully or partially exposed to a 2.5% or 9.8% NaOCl solution. In three successive studies, biological dissolution-capacity of NaOCl was tested under different conditions. In experiment 1 the effect of volume/time, in experiment 2 the time/concentration/renewal frequency and in experiment 3 the contact area/renewal frequency/concentration/time of 2.5% or 9.8% NaOCl solutions on dissolving-capacity of organic matter were studied. The weight loss of gelatine pieces over time was registered. The non-parametric tests of Mann-Whitney and Kruskal-Wallis at the 5% threshold were used for statistical analysis.

Results

The differences between the two concentrations of NaOCl solution (2.5% and 9.8%) are statistically significant in the effects of different volumes on total dissolution time (P<0.05). Differences in weight loss according to the concentration of the NaOCl solution used (2.5% or 9.8%) were significant after 2 min of contact time (P<0.05). Differences in weight loss between the model and the tube are significant (P<0.05) when the solution is repeated every 30 sec and every 1 min after 2 min of contact.

Conclusion

This in vitro study showed that using a more concentrated NaOCl solution would certainly improve the endodontic disinfection, but the biological risk in case of apical extrusion should be considered.

Effects of Calcium Hypochlorite and Sodium Hypochlorite, as Root Canal Irrigants, on the Bond Strength of Glass Fiber Posts Cemented with Self-Adhesive Resin Cement

Objectives:

Calcium hypochlorite (Ca(OCl)₂) is currently used as a root canal irrigant. The aim of this study was to compare the effects of calcium hypochlorite and sodium hypochlorite (NaOCl), as root canal irrigants, on the bond strength of posts cemented with a self-adhesive resin cement.

Materials and Methods:

In this in-vitro study, 40 maxillary central incisors with similar root lengths were decoronated. The teeth were randomly divided into five groups based on the irrigant used: Group 1: normal saline (control), Group 2: 2.5% sodium hypochlorite, Group 3: 5.25% sodium hypochlorite, Group 4: 2.5% calcium hypochlorite, and Group 5: 5% calcium hypochlorite. Root canal treatments were performed with Gates-Glidden drills and the irrigant corresponding to each group was used upon changing the file and for irrigating the post space. Then, glass fiber posts were cemented by BisCem self-adhesive cement. After applying 1,000 thermocycles at 5–55°C, three samples of the mid-section of each root were prepared: one for scanning electron microscopy (SEM), and the rest for push-out testing. Data were analyzed with SPSS 23 software using one-way analysis of variance and post-hoc Tukey’s test.

Results:

The highest and lowest mean bond strengths were recorded in groups 5 and 1, respectively. There was a significant difference between the 5% calcium hypochlorite group and the other groups (P<0.001). The difference between the other groups was not significant.

Conclusion:

The use of 5% calcium hypochlorite with self-adhesive cements increases the push-out bond strength of fiber posts to radicular dentin.

Difference between the Actual and Labeled Concentrations of Several Domestic Brands of Sodium Hypochlorite

Introduction

Sodium hypochlorite (NaOCl) is extensively used in root canal treatment and its efficacy depends on the concentration of free available chlorine (FAC). This study aimed to assess the chlorine content of 10 domestically manufactured household bleach products available in the Iranian market and evaluate the effect of temperature, time and daily bottle uncapping on FAC concentration and pH of these products.

Methods and Materials

One-liter bottles of 10 available brands of household bleach (n=4 of each brand) were collected and randomly divided into four groups (n=10). Two groups were refrigerated at 4^°C while the remaining two were stored at room temperature. One group of refrigerated and one group of room temperature samples were subjected to daily bottle uncapping followed by agitation and recapping for 3 months (six times a week to simulate weekly office work). The remaining bottles remained untouched and served as controls. The concentration of FAC in each sample was measured using the iodometric titration assay, and the pH was measured using a calibrated pH-meter at baseline and 1, 2 and 3 months. The results were analyzed using the one-way ANOVA and t-test.

Results

The mean concentration of FAC in the solutions was 4.87±0.19% at baseline. The measured concentration of sodium hypochlorite was different from the labeled value. The concentration of FAC decreased over time in all samples; the greatest reduction occurred in room temperature samples subjected to daily uncapping while the smallest reduction occurred in refrigerated, capped bottles (19% and 1.9%, respectively). The pH of all products decreased over time. The mean reduction in pH was 1.1 for the samples stored at room temperature for 3 months and 0.8 for the refrigerated samples.

Conclusion

This in vitro study showed that the expected concentration of sodium hypochlorite solution made of household bleach for endodontic purposes is different from its actual concentration.

Effect of a New Imidazolium-based Silver Nanoparticle Irrigant on the Bond Strength of Epoxy Resin Sealer to Root Canal Dentine

Introduction

The aim of this study was to evaluate the effect of a new imidazolium-based silver nanoparticle (ImSNP) root canal irrigant on the bond strength of AH-Plus sealer to root canal dentine.

Methods and Materials

Forty single-rooted extracted human teeth were used in this study. The crowns were resected and according to the irrigation solutions used during root canal preparation, the roots were divided into 5 groups (n=8): Group 1: normal saline (control group), Group 2: 2.5% Sodium Hypochlorite (NaOCl), Group 3: 2.5% NaOCl+17% ethylene diamin tetracetic acid (EDTA), Group 4: silver nanoparticles (AgNPs), Group 5: AgNPs +17% EDTA. After root canal instrumentation, the canals were filled with AH-Plus. Then, after 7 days, 2 or 3 dentine disks were obtained from the mid-root of each sample. Bond strength was measured by the push-out test. Additionally, failure patterns were classified as adhesive, cohesive and mixed. Data were statistically analyzed by one-way ANOVA and Tamhane post hoc tests. The level of significance was set at 0.05.

Results

There was no statistically significant differences between groups (P>0.05). Groups 4 (AgNPs), 3 (2.5% NaOCl+17% EDTA) and 2 (2.5% NaOCl) showed statistically higher bond strength compared to group 1 (control group) (P<0.05). Also, Group 4 showed a significant difference with group 5 (AgNPs+17% EDTA) (P=0.017). The failure patterns were mainly cohesive.

Conclusion

This in vitro study showed that, when used without EDTA, AgNPs improved the bond strength of AH-Plus to radicular dentine.

Evaluation of Antimicrobial Effcacy of Calcium Hypochlorite as an Endodontic Irrigant on a Mixed-Culture Biofilm: An Ex vivo Study

Introduction

Calcium hypochlorite (CH) has been recently suggested as an endodontic irrigant. The aim of this investigation was to evaluate the antimicrobial efficacy of CH compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX) against multispecies biofilm in surface and deep dentinal tubules.

Methods and Materials

Minimal inhibitory concentration (MIC) of irrigant agents was assessed using a microdilution method. One hundred and twenty of human maxillary incisor teeth were prepared and infected with suspension of Entrococcus faecalis, Fusobacterium nucleatum and Prevotella intermedia in an anaerobic jar for 7 days. Depending on irrigation solutions, specimens were divided into 4 groups (n=30); group 1: 2% CHX, group 2: 5.25% sodium hypochlorite, group 3: 5% calcium hypochlorite, group 4: positive control (normal saline (NS)). Fifteen remained specimens were used as negative control. Surviving bacteria were sampled before (S1) and after irrigation from surface (S2) and deep (S3) dentin. The medium turbidity was visualized with spectrophotometry. Data were analyzed using analysis of variance followed by Tukey post hoc test (α=0.05).

Results

The MIC of CH against E. faecalis, F. nucleatum and P. intermedia was 25, 8 and 7.5 µg/mL respectively. There were no significant differences in S1 among the test groups. Moreover, 2% CHX and 5% CH had significantly lower medium turbidity at both S2 and S3, in comparison with 5.25% NaOCl (P=0.018 and 0.031, respectively). But there were no significant differences between 2% CHX and 5% CH at both S2 and S3 (P=0.862 and 0.978, respectively).

Conclusion

Under the conditions of this ex vivo study, 5% CH and 2% CHX are more effective than 5.25% NaOCl in the reduction of mixed-culture biofilm.

Effectiveness of Sodium Hypochlorite plus EDTA Compared with Peracetic Acid in Removing Smear Layer and Killing Enterococcus faecalis

Introduction

The aim of this study was to evaluate the effectiveness of 2.5% sodium hypochlorite associated with 17% Ethylenediaminetetraacetic acid (NaOCl-EDTA), versus that of 1% peracetic acid (PA), in removing the smear layer, as assessed by scanning electron microscopy (SEM), and in exerting bactericidal action against Enterococcus faecalis (E. faecalis ) , as assessed by the real-time polymerase chain reaction (real-time PCR).

Methods and Materials

Fifty-five extracted mandibular single-rooted premolars were selected, and divided into two experimental groups (NaOCl-EDTA and PA; n=25) and one control group (0.9% saline; n=5). Pre- and post-instrumentation samples were collected and assessed for the presence of E. faecalis using real-time PCR. The teeth were instrumented using hand files and the ProTaper Universal system (hybrid technique) for a standardized time of 7 min. A total of 20 mL of NaOCl followed by 5 mL of EDTA were applied during instrumentation in the NaOCl-EDTA group, whereas 20 mL of PA and 20 mL of saline were applied in the PA and control groups, respectively. An additional 5 mL of saline was applied in all the groups to neutralize the environment. A scoring system was used to conduct the SEM assessment. The results were submitted to the Kruskal-Wallis test, complemented by Dunn's test (SEM analysis) (P<0.05).

Results

A significant microbial reduction was observed in both the PA and the NaOCl-EDTA groups (P<0.05). In the PA group, the presence of a smear layer in the apical third was significantly greater than in the cervical third (P<0.05); no significant differences were observed between the middle and cervical thirds, or between the middle and apical thirds (P>0.05). In the NaOCl-EDTA group, the smear layer scores were significantly higher in the apical third than in the cervical and middle thirds (P<0.05).

Conclusion

This in vitro study showed that there was no significant difference between PA and NaOCl-EDTA irrigation regimens regarding either antimicrobial action against E. faecalis or removal of the smear layer, except for greater removal in the middle third by the NaOCl-EDTA group.

The Effectiveness of Sonic-Activated Irrigation in Reducing Intratubular Enterococcus faecalis

Introduction

The purpose of this in vitro study was to compare the effectiveness of sonic activation and syringe irrigation of 5.25% sodium hypochlorite in removing the Enterococcus faecalis (E. faecalis) biofilm.

Methods and Materials

Root canals of 54 extracted human single-rooted central incisors were prepared with ProTaper S1-S2-F1-F2 and Gates Gliden burs size 1, and 2 at the working length. After sterilization, the root canals were contaminated with E. faecalis suspension and randomly assigned to three groups: G1, conventional syringe irrigation; G2, sonic agitation of NaOCl with Endo Activator system; and G3, no subjected to the mentioned irrigation techniques (negative control). Canals were sampled after the disinfection procedure. The colony forming units (CFU) count was evaluated. Samples were also visualized under fluorescent microscope to count viable bacteria. Data were statistically analyzed using the Kruskal-Wallis and one-way ANOVA followed by Tukey's test (P<0.05).

Results

There was a significant reduction in the CFU count after both irrigation techniques. There was no significant difference between two techniques (P=0.874). Using bacterial viability kit, Endo Activator displayed the least viable bacteria than the other groups (P<0.001) and control group showed the greatest one (P<0.001).

Conclusion

In this in vitro study, the Endo Activator system was more successful in reducing intratubular viable bacteria compared with NaOCl syringe irrigation alone.

Effect of Different Irrigants Applied After Post Space Preparation on Push-Out Bond Strength of a Self-Etch Resin Cement

OBJECTIVES

The aim was to investigate the effect of intracanal irrigants and agents on the bond strength of intraradicular fiber posts to dentin.

MATERIALS AND METHODS

Root canals of 72 decoronated single-rooted premolars were cleaned, shaped, and obturated with gutta-percha and AH26. The specimens were incubated at 37°C and 100% humidity for seven days. Next, the coronal 10 mm of the canals were prepared to receive size 2 D.T. Light fiber post, and the specimens were randomly allocated into six groups according to the irrigants used after post space preparation: normal saline (control group), 5.25% sodium hypochlorite (NaOCl)/15 seconds, 17% ethylenediaminetetraacetic acid (EDTA)/60 seconds, 2% chlorhexidine (CHX)/5 minutes, MTAD/5 minutes, and acid-etching/15 seconds. All canals were rinsed with normal saline and dried. Fiber posts were cemented using Panavia F2.0. After 24 hours, two mid-root slices of 1mm thickness were obtained from each specimen. Push-out bond strength test was performed in a universal testing machine at 0.5mm/minute. The maximum applied load was recorded, and the bond strength was calculated in megapascal (MPa). Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's test.

RESULTS

The mean shear bond strengths of etched (53.21±12.11 MPa), MTAD (52.47±14.75 MPa) and EDTA (49.08±10.19 MPa) groups were significantly higher than that of the control group (39.82±10.04 MPa). The difference was marginally significant for CHX group (49.8±13.57 MPa) and not significant for NaOCl group (47.15±17.64 MPa).

CONCLUSIONS

Etching or irrigating the root canals with MTAD or EDTA after post space preparation increases the bond strength of Panavia F2.0 to dentin.

The Antifungal Effect of Propolis Endodontic Irrigant with Three Other Irrigation Solutions in Presence and Absence of Smear Layer: An In Vitro Study

INTRODUCTION

The aim of this in vitro study was to compare the antifungal effect of propolis as an endodontic irrigant agent with a mixture of doxycycline, citric acid, and a detergent mixture (MTAD), 2% chlorhexidine (CHX) and 3% sodium hypochlorite (NaOCl) against Candida albicans in presence and absence of smear layer.

METHODS AND MATERIALS

Extracted teeth with single canals (n=104) were prepared and randomly distributed into four experimental groups; 30% propolis, MTAD, 2% CHX and 3% NaOCl. Each group had two subgroups; with and without smear layer. The antifungal effectiveness was evaluated. The Kruskal-Wallis and Mann-Whitney tests were used to compare the overall effectiveness of different treatments at significance level of 0.05.

RESULTS

Propolis, CHX and NaOCl had similar levels of effectiveness to each other against C. albicans, and these levels were not affected by the presence or absence of the smear layer. Each irrigant was significantly more effective than MTAD or saline solution. MTAD was less effective in the presence of the smear layer than in its absence.

CONCLUSIONS

Propolis irrigation can produce root canals that are free of C. albicans, even in the presence of the smear layer.

Deproteinizing Agents as an Effective Enamel Bond Enhancer-An in Vitro Study

OBJECTIVE

The aim of this study was to compare the effect of different deproteinizing agents on shear bond strength of composite to primary teeth enamel.

STUDY DESIGN

Forty sound primary molars divided in 4 groups of 10 teeth each. In control group 1, enamel was etched for 60 seconds with 37% phosphoric acid and rinsed with water. Group 2: after acid etching deproteinizing agent 5 % sodium hypochlorite was applied for 60 seconds and rinsed. Group 3: after acid etching deproteinizing agent papain gel was applied for 60 seconds and rinsed. Group 4: after acid etching deproteinizing agent bromelain gel applied for 60 seconds and rinsed. Following this, bonding agent was applied to treated enamel surface and composite resin disc were build. Samples were then tested for shear bond strength using Universal Testing Machine.

RESULTS

Mean SBS was highest for group 4 and lowest for group 1. No statistically significant difference (p value >0.05) was found between all the four groups.

CONCLUSION

Among deproteinizing agents, deproteinization when carried out with bromelain gel and sodium hypochlorite showed effective bond strength as compared to papain.

The in Vitro Antibacterial Efficacy of Persian Green Tea Extract as an Intracanal Irrigant on Enterococcus faecalis Biofilm

Introduction:

The aim of this study was to compare the antibacterial effect of Persian green tea extract (GTE) and 2.5% sodium hypochlorite (NaOCl) against Enterococcus faecalis (E. faecalis) as an intracanal irrigant.

Methods and Materials:

Thirty freshly extracted teeth were instrumented and sectioned into mesial and distal segments. The specimens were put into wells containing 2 mL of E. faecalis-containing medium. After 3 weeks, the specimens were removed and divided randomly into three groups (n=20). Each group was exposed to 3 mL of different irrigants for 3 min. Groups 1, 2 and 3 were irrigated with GTE, 2.5% NaOCl and normal saline, respectively. Biofilm formed in the middle third of the root canal was carved by sterile scalpel and cultured in Mueller-Hinton medium. Number of colony forming units (CFU) was counted on each plate. In addition, antimicrobial activity of the irrigants was evaluated by the agar disc diffusion test. The diameter of inhibition zone (IZ) around each irrigant was evaluated. The Kruskal-Wallis and Dunn tests were used to analysis the data.

Results:

While in NaOCl group no bacterial colonies were observed, the mean number of E. faecalis in GTE and control groups were 275±74 CFU/mL (P<0.001) and 119×10⁸±11×10⁸ (P<0.001), respectively. The mean of IZ in NaOCl and GTE groups were 24.35±0.78 and 6.9±0.87 mm, in order of appearance (P<0.001). Zone of inhibition was not observed around the control group (P<0.001).

Conclusion:

This research highlighted the potential role of plant extracts in antimicrobial root canal irrigation protocol.

Antimicrobial Efficacy and Cytocompatibility of Calcium Hypochlorite Solution as a Root Canal Irrigant: An in Vitro Investigation

INTRODUCTION

The purpose of this study was to compare the antimicrobial efficacy of sodium hypochlorite (SH) and calcium hypochlorite (CH) against Enterococcus faecalis (E. faecalis) using quantitative real-time polymerase chain reaction (qPCR) analysis and also to compare their cytocompatibility on L929 murine fibroblasts using Mossman's tetrazolium toxicity (MTT) assay.

METHODS AND MATERIALS

A broth micro-dilution susceptibility test was used to determine the minimum inhibitory concentration (MIC) of each irrigant against E. faecalis. Then, the root canals of 50 mature extracted human mandibular premolars were contaminated with E. faecalis and were randomly divided into three groups according to the irrigant used (n=20). Canals were irrigated with SH in group I (n=20) and CH in group II (n=20) at their obtained MIC. In group III (n=10), sterile saline was used. Microbial sampling was performed before and after biomechanical preparation. Quantitative PCR was used to quantify E. faecalis in the root canal samples. For cytocompatibility assessment, L929 murine fibroblasts were exposed to various concentrations of the irrigants.

RESULTS

Irrigation with test materials resulted in significant reduction in colony forming units (CFU) in post-instrumentation samples (with the MIC values of SH and CH against E. faecalis being 0.5% and 5%, respectively). However, the reduction in the normal saline group was not significant (P=0.203). In addition, 5% CH was more effective than 0.5% SH (P=0.006) in eliminating E. faecalis. Among the different concentrations of tested irrigants, 0.5% CH and 5% SH showed the least and the most cytotoxicity, respectively (P<0.001). The cytotoxicity of 5% CH and 0.5% SH was similar (P=0.99), and lower than 2.5% SH (P<0.001).

CONCLUSION

CH at an MIC of 5% was effective in eliminating E. faecalis in planktonic state and also its biofilm and exhibited comparable cytocompatibility to that of 0.5% SH.

The Antibacterial Efficacy of Photo-Activated Disinfection, Chlorhexidine and Sodium Hypochlorite in Infected Root Canals: An in Vitro Study

INTRODUCTION

This study compared the efficacy of light-activated low-power laser, 2% chlorhexidine (CHX) and 2.5% NaOCl in eliminating Enterococcus faecalis (E. faecalis) from the root canal system.

METHODS AND MATERIALS

The root canals of 60 maxillary central incisors were contaminated with E. faecalis and then the bacteria were incubated for 24 h. All the root canals were instrumented in a crown-down manner with #4 and 3 Gates-Glidden drills, followed by RaCe rotary files (40/0.10, 35/0.08, and 30/0.06). The samples were randomly assigned to three experimental groups and one control group (n=15). In the control group no intervention was made. In the photo-activated disinfection (PAD) group, laser therapy was undertaken with diode laser beams (with an output power of 100 mW/cm(2)) for 120 sec. For the other two experimental groups, root canals were irrigated either with 5 mL of 2% CHX or 2.5% NaOCl solutions, respectively. The Kruskal-Wallis test was used to compare the CFU values of the bacteria and post-hoc Bonferroni test was used for pairwise comparisons. The level of significance was set at 0.05.

RESULTS

The inhibition of bacterial growth in all the experimental groups was significantly superior to the control group (P<0.05). There was no significant difference between the effect of PAD and 2% CHX (P=0.05). The effect of 2.5% NaOCl was significantly better than that of the PAD technique (P<0.001). In addition, 2.5% NaOCl was significantly better than 2% CHX (P=0.007).

CONCLUSION

Photodynamic therapy was effective in reducing the E. faecalis counts in comparison with the control group, but 2.5% NaOCl solution was the most effective protocol.

The Effect of Canal Dryness on Bond Strength of Bioceramic and Epoxy-resin Sealers after Irrigation with Sodium Hypochlorite or Chlorhexidine

Introduction:

The aim of this in vitro study was to evaluate the effect of canal dryness on the push-out bond strength of two resin sealers (AH-Plus and Adseal) and a bioceramic sealer (Endosequence BC sealer) after canal irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX).

Methods and Materials:

A total of 18 extracted human premolars were used. Canals were prepared and were divided to two groups based on irrigation solution (either NaOCl or CHX). The samples were again divided based on pre-obturation canal condition (wet, half-wet and dry). The samples were sub-divided into 3 groups based on the sealer type; the teeth were obturated with gutta-percha and test sealers (Adseal, AH-Plus or BC sealer). A total number of 18 groups were available to be cut into dentine disks (12 disks in each group). The type of bond failure was also assessed in each group. Data were analyzed using the 3-way ANOVA, post hoc Tukey’s tests, t-test and the Fisher’s exact test. The level of significance was set at 0.05.

Results:

The bond strength of Adseal was not affected by the canal condition or irrigation with either NaOCl or CHX. Although the bond strength of AH-Plus was not affected by the irrigant type, the highest bond strength was seen in dry canals. For Endosequence BC sealer, the canal conditions did not affect the bond strength; however, CHX reduced the bond strength.

Conclusion:

Bond strength of resin sealers was not affected by irrigation solution; however, canal moisture negatively affected the bond strength of AH-Plus. CHX reduced the bond strength of BC sealer.

Impact of Ultrasonic Activation on the Effectiveness of Sodium Hypochlorite: A Review

Using ultrasonic devices in endodontics can enhance the antibacterial and tissue dissolving ability of different root canal irrigants such as sodium hypochlorite (NaOCl) which is the most common irrigant with excellent antibacterial and tissue dissolving abilities. However, due to its high surface tension, its penetration into the irregularities of the root canal system is a challenge. The purpose of this paper was to review the different ultrasonic devices, different types of ultrasonic irrigation, the effect(s) of ultrasonic activation on the antibacterial and biofilm-removal abilities of NaOCl as well as the effect of ultrasonic activation on the smear layer removal ability of NaOCl.

The Effect of Smear Layer on Antimicrobial Efficacy of Three Root Canal Irrigants

Introduction:

One of the main goals of endodontic treatment is to decrease the harboring bacteria within the root canal system and dentinal tubules. This experimental study attempted to investigate the antibacterial efficacy of three root canal irrigants in the presence and absence of smear layer (SL).

Methods and Materials:

A total of 210 sound extracted human single-rooted teeth were prepared. After creating the SL and its removal in half of the samples, they were infected with Candida albicans (C. albicans) and Actinomyces israelii (A. israelii). A total of 180 specimen were used to assess the antimicrobial efficacy of the three irrigants in presence and absence of SL, 24 specimen were placed in the positive and negative controls, 2 samples were utilized for scanning electron microscopy (SEM) analysis and 2 were used for Gram staining. Then, they were exposed to irrigants including 2.61% sodium hypochlorite (NaOCl), 0.2% chlorhexidine gluconate (CHX) and 1% povidone-iodine (PI) for 5, 30 and 60 min. Presence/absence of test microorganisms was determined by incubation of specimens in test tubes containing brain-heart infusion (BHI) broth and then measuring the colony forming units (CFU) on BHI agar. A cumulative logistic model was used to analyze the ordinal response.

Results:

The 2.61% solution of NaOCl was significantly more effective than 0.2% CHX and the latter was more efficient than 1% PI for decreasing fungal and microbial infection of dentinal tubules in the presence and absence of SL.

Conclusion:

The presence of smear layer decreased the efficacy of antimicrobial irrigants. The minimum time required for elimination of fungal/microbial infection was 30 min.

Effects of Chlorhexidine and Sodium Hypochlorite on the Setting Time of Calcium-Enriched Mixture Cement

Introduction:

The aim of the present study was to evaluate whether adding 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) to calcium-enriched mixture (CEM) cement would affect its setting time (ST), or not.

Methods and Materials:

In this study, the setting time of CEM cement was evaluated in three groups (n=9) as follows: group 1; CEM cement, group 2; CEM cement+2% CHX and group 3; CEM cement+2.6% NaOCl. Then the mean values of ST were calculated and the Kolmogorov-Smirnov test was used to evaluate the normal distribution of data. The Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. Statistical significance was set at 0.05.

Results:

The mean ST for groups 1, 2 and 3 were 105, 120 and 220 min, respectively. There was a significant increase in the duration of ST in group 3 (NaOCl) in comparison with the two other groups (P<0.05).

Conclusion:

NaOCl significantly increased the ST of CEM cement, whereas chlorhexidine did not alter the ST.

The in vitro Effect of Irrigants with Low Surface Tension on Enterococcus faecalis

Introduction:

Due to the complex anatomy of the root canal system and high surface tension of common root canal irrigants (RCI), conducting an investigation on RCIs containing surfactants is a priority. The aim of this in vitro study was to verify the antibacterial potential of RCI with low surface tension in root canals infected with Enterococcus faecalis (E. faecalis).

Methods and Materials:

Thirty-five extracted human maxillary anterior teeth were prepared and inoculated with E. faecalis for 60 days. After root canal preparation, the teeth were randomly divided to one positive and one negative control groups and 5 experimental groups: Hypoclean/Tetraclean NA, Hypoclean, Tetraclean, NaOCl/Tetraclean and NaOCl. Bacterial growth was observed by turbidity of culture medium and then measured using a UV spectrophotometer. Data were analyzed in three time intervals (pre-instrumentation and, 20 min and 72 h after canal preparation) using the ANOVA and post hoc Tukey’s tests. The level of significance was set at 0.05.

Results:

The results indicated the presence of E. faecalis in all post-irrigation samples irrespective of the RCI. However, the optical densities in both post-irrigation periods showed bacterial reduction and significant differences between groups.

Conclusion:

RCI with low surface tension showed antibacterial potential in E. faecalis infected roots.

Agonistic and Antagonistic Interactions between Chlorhexidine and Other Endodontic Agents: A Critical Review

Root canal irrigants play a significant role in elimination of the microorganisms, tissue remnants, and removal of the debris and smear layer. No single solution is able to fulfill all these actions completely; therefore, a combination of irrigants may be required. The aim of this investigation was to review the agonistic and antagonistic interactions between chlorhexidine (CHX) and other irrigants and medicaments. An English-limited Medline search was performed for articles published from 2002 to 2014. The searched keywords included: chlorhexidine AND sodium hypochlorite/ethylenediaminetetraacetic acid/calcium hydroxide/mineral trioxide aggregate. Subsequently, a hand search was carried out on the references of result articles to find more matching papers. Findings showed that the combination of CHX and sodium hypochlorite (NaOCl) causes color changes and the formation of a neutral and insoluble precipitate; CHX forms a salt with ethylenediaminetetraacetic acid (EDTA). In addition, it has been demonstrated that the alkalinity of calcium hydroxide (CH) remained unchanged after mixing with CHX. Furthermore, mixing CHX with CH may enhance its antimicrobial activity; also mixing mineral trioxide aggregate (MTA) powder with CHX increases its antimicrobial activity but this may negatively affect its mechanical properties.

A comparative study of antifungal activity of endodontic irrigants

INTRODUCTION

The purpose of this in vitro study was to assess the antifungal activity of final canal rinse with either three concentrations of sodium hypochlorite (NaOCl) (0.5, 2.6 and 6%), two concentrations of chlorhexidine (CHX) (2% and 0.2%), MTAD, Tetraclean, Hypoclean and Chlor-Xtra on Candida albicans (C. albicans) in a human tooth model.

METHODS AND MATERIALS

Two hundred and thirty five extracted human maxillary central and lateral incisors were used in this study. Teeth were randomly divided into nine test groups (n=25) and positive and a negative control groups (n=5). After cleaning and shaping, teeth were contaminated with C. albicans and incubated for 72 h. The irrigation solution in nine experimental groups included: 6% NaOCl, 2.6% NaOCl, 0.5% NaOCl, 2% CHX, 0.2% CHX, MTAD, Tetraclean, Hypoclean and Chlor-Xtra. After culturing on Sabouraud 4% dextrose agar, colony-forming units (CFU) were counted.

RESULTS

6% NaOCl, 2% CHX and Chlor-Xtra were equally effective (P>0.05) and significantly superior to MTAD and Tetraclean (P<0.05). In addition, the effectiveness of Tetraclean and MTAD was significantly less than Hypoclean, NaOCl at all concentrations (6% 2.6% and 0.5%), MTAD and 0.2% CHX (P<0.05). Furthermore, Tetraclean was significantly more effective than MTAD (P<0.05).

CONCLUSION

Antifungal activity of 6% NaOCl, Chlor-Xtra and 2% CHX was significantly greater than 2.6% NaOCl, 0.5% NaOCl, MTAD, 0.2% CHX and Tetraclean.

Effectiveness of four different final irrigation activation techniques on smear layer removal in curved root canals : a scanning electron microscopy study

OBJECTIVE

The aim of this study was to assess the efficacy of apical negative pressure (ANP), manual dynamic agitation (MDA), passive ultrasonic irrigation (PUI) and needle irrigation (NI) as final irrigation activation techniques for smear layer removal in curved root canals.

MATERIALS AND METHODS

Mesiobuccal root canals of 80 freshly extracted maxillary first molars with curvatures ranging between 25° and 35° were used. A glide path with #08-15 K files was established before cleaning and shaping with Mtwo rotary instruments (VDW, Munich, Germany) up to size 35/0.04 taper. During instrumentation, 1 ml of 2.5% NaOCl was used at each change of file. Samples were divided into 4 equal groups (n=20) according to the final irrigation activation technique: group 1, apical negative pressure (ANP) (EndoVac); group 2, manual dynamic agitation (MDA); group 3, passive ultrasonic irrigation (PUI); and group 4, needle irrigation (NI). Root canals were split longitudinally and subjected to scanning electron microscopy. The presence of smear layer at coronal, middle and apical levels was evaluated by superimposing 300-μm square grid over the obtained photomicrographs using a four-score scale with X1,000 magnification.

RESULTS

Amongst all the groups tested, ANP showed the overall best smear layer removal efficacy (p < 0.05). Removal of smear layer was least effective with the NI technique.

CONCLUSION

ANP (EndoVac system) can be used as the final irrigation activation technique for effective smear layer removal in curved root canals.

An update on the management of endodontic biofilms using root canal irrigants and medicaments

Microbial biofilm is defined as a sessile multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self-produced matrix of extracellular polymeric substances. Biofilms play a very important role in pulp and periradicular pathosis. The aim of this article was to review the role of endodontic biofilms and the effects of root canal irrigants, medicaments as well as lasers on biofilms A Medline search was performed on the English articles published from 1982 to 2013 and was limited to papers published in English. The searched keywords were "Biofilms AND endodontics", "Biofilms AND sodium hypochlorite", "Biofilms AND chlorhexidine", "Biofilms AND MTAD", "Biofilms AND calcium hydroxide", "Biofilms AND ozone", "Biofilms AND lasers" and "Biofilms AND nanoparticles". The reference list of each article was manually searched to find other suitable sources of information.

An in vitro comparison of the antibacterial efficacy of triphala with different concentrations of sodium hypochlorite

INTRODUCTION

The antimicrobial efficacy of root canal irrigant plays an important role in increasing the success of root canal treatment (RCT). The aim of the present experimental study was to compare the antimicrobial activity of Triphala (a plant-derived solution) with 0.5, 1, 2.5 and 5% concentrations of sodium hypochlorite (NaOCl), against Enterococcus faecalis (E. faecalis).

METHODS AND MATERIALS

Two hundred plates of cultured E. faecalis, were divided into 5 experimental groups (n=38) and two positive and negative control groups. The antimicrobial activity of the test solutions was determined by measuring the zone of inhibition in the culture media. The mean diameter of inhibited zones between the study groups was compared using the Kruskal-Wallis test and the Mann-Whitney U test was used for the two-by-two comparison of the groups with the level of significance set at 0.05.

RESULTS

The Kruskal-Wallis test showed significant differences between the study groups (P<0.05). According to the Mann-Whitney U test the mean diameter of inhibition zones in Triphala group was significantly higher compared to 0.5 and 1% NaOCl (P<0.05).

CONCLUSION

In this study, Triphala exhibited better antimicrobial activity against E. faecalis compared to 0.5 and 1% NaOCl (P<0.05).

A review of antibacterial agents in endodontic treatment

Microorganisms play a major role in initiation and perpetuation of pulpal and periapical diseases. Therefore, elimination of the microorganisms present in the root canal system is the fundamental objective of endodontic treatment. The use of mechanical debridement, chemical irrigation or other antimicrobial protocols and intra-canal medicaments are critical to attain this goal. The aim of this article was to review the antimicrobial agents and their properties in endodontics.

Comparison of Endodontic Treatment Results Yielded from Using Normal Saline with IKI Final Rinse or NaOCl Irrigation: A 30-Month Follow-up Study

INTRODUCTION

The aim of this clinical trial was to evaluate and compare the endodontic treatment results of teeth with apical periodontitis after thirty-month recall with two different irrigation regimen: normal saline followed by Iodine Potassium Iodide (IKI) or sodium hypochlorite (NaOCl) irrigation alone.

MATERIALS AND METHODS

Twenty seven patients (30 teeth) who had been included in the first part of our antimicrobial survey were recalled. In previous stage, root canal treatments were performed using either normal saline with IKI final rinse (n = 15) or NaOCl (n = 15) as irrigating solutions. Bacterial samples were taken before and after instrumentation. In this stage, three patients (6 teeth) were excluded from the follow-up schedule since they did not respond to the recall requests. The remaining 24 subjects (12 teeth in each NaOCl and IKI group) were examined clinically and radiologically. Post-operative and follow-up images were coded, blindly evaluated and given a periapical score according to PAI scoring system. The outcome was assessed in two ways; first, the changes in PAI score from base line to the follow-up evaluation in each group were assessed by wilcoxon signed rank test. In addition, Mann-Whitney U test was used to compare the differences between the post-operative and follow-up images of treatment groups. Second, the dichotomous variables as "healed" or "not healed" were compared.

RESULTS

The Median (Min, Max) PAI scores for NaOCl group and IKI group were both 5 (3, 5) for immediate post-operative radiographs and declined to 1 (1, 2) and 2 (1, 2), respectively. A statistically significant decrease in PAI score from the base line to the follow-up evaluation was seen in both groups (P = 0.002). The decrease in NaOCl group was higher significantly in comparison to IKI group (P = 0.036). One hundred percent of the teeth were healed in both groups (PAI ≤ 2) and no teeth showed any abnormal clinical findings.

CONCLUSION

Root canal irrigation with NaOCl resulted in a significant higher decrease in PAI scores in comparison to irrigation with normal saline followed by IKI final rinse. Although, according to results of 30-months recall, complete bone formation was observed in all samples in both groups and no teeth showed any abnormal clinical findings. These findings depict the weight of all important clinical and biological factors which together impact the results of a successful endodontic treatment.

Comparative evaluation of sodium hypochlorite and microwave disinfection on dimensional stability of denture bases

PURPOSE

To compare the effect of sodium hypochlorite and microwave disinfection on the dimensional stability of denture bases without and with relining.

MATERIALS AND METHODS

A brass die was prepared by simulating an edentulous maxillary arch. It was used to fabricate 1.5 mm and 3 mm of thickness denture bases (n = 40). The 1.5 mm of thickness-specimens (n = 20) were relined with 1.5 mm of autopolymerizing relining resin. Five holes were prepared over crest of ridge of brass die with intimately fitting stainless steel pins which were transferred to the intaglio surface of specimens during fabrication of denture bases. For calculation of dimensional changes in denture bases, differences between the baseline area before and after disinfection of the specimens were used. The denture bases without and with relining were divided into 2 groups (each n = 20). Data were analyzed using student paired 't' and unpaired 't' test.

RESULTS

Microwave disinfection produces significant shrinkage in both denture bases without relining (t = 17.16; P<.001) and with relining (t = 14.9; P<.001). Denture bases without relining showed more shrinkage when compared with relined denture bases after microwave disinfection (t = 6.09; P<.001). The changes in dimensional stability after sodium hypochlorite disinfection were not significant for both denture bases without relining (t = 2.19; P=.056) and denture bases with relining (t = 2.17; P=.058).

CONCLUSION

Microwave disinfection leads to increased shrinkage of denture bases without and with relining. Chemical disinfection with sodium hypochlorite seems to be a safer method of disinfection with regards to physical properties such as changes in dimensional stability.

The effect of ascorbic Acid on the substantivity of tetraclean in sodium hypochlorite-treated bovine dentin

OBJECTIVE

The purpose of this study was to assess the in vitro effect of ascorbic acid on the antibacterial substantivity of Tetraclean in bovine root dentin pretreated with sodium hypochlorite (NaOCl).

MATERIALS AND METHODS

Eighty dentin tubes prepared from bovine incisor teeth were infected with Enterococcus faecalis for 14 days. The specimens were divided into five groups as follows: Tetraclean; 5.25% NaOCl/Tetraclean; 5.25% NaOCl/ascorbic acid/Tetraclean; infected dentin tubes (positive control); and sterile dentin tubes (negative control). At experimental times of 0, 7, 14, 21 and 28 days, dentin chips were removed from the canals by sequential sterile low-speed round burs with increasing diameters of 025, 027, 029, 031 and 033 ISO sizes, respectively. After culturing, the number of colony-forming units (CFU) was counted.

RESULTS

In all experimental groups, the number of CFU was minimum in the first cultures and the results obtained were significantly different at any time period (p < 0.05). The Tetraclean group showed the most effective antibacterial action at all five experimental periods (p < 0.05). NaOCl/Tetraclean group showed the least antibacterial activity at all time periods. The NaOCl/ascorbic acid/Tetraclean group showed similar antibacterial substantivity to the Tetraclean group at all time periods (p> 0.05).

CONCLUSION

Ascorbic acid prevents the decrease of residual antibacterial activity of Tetraclean in dentin samples pretreated with NaOCl.

A histopathological comparison of pulpotomy with sodium hypochlorite and formocresol

INTRODUCTION

Formocresol is widely used in primary teeth pulpotomies; however it is known to have several side effects. The purpose of this study was to assess pulpal changes of primary teeth pulps after pulpotomy with sodium hypochlorite and formocresol.

MATERIALS AND METHODS

In this randomized clinical trial, 22 teeth were selected. These teeth were randomly divided into 2 groups (formocresol; n=11 and sodium hypochlorite n=11). Two months post-operatively teeth were extracted and pulpal responses were evaluated by recording the degree of inflammation and extent of pulpal involvement. Dentinal bridge formation was also evaluated. Finally the data was analyzed with McNemartest.

RESULTS

The formocresol group demonstrated mild inflammation in 4 cases whereas sodium hypochlorite had mild inflammation in six cases. Severe inflammation was only found in 1 case in the sodium hypochlorite group, but it was present in 4 cases in the formocresol group. In sodium hypochlorite group there were no cases of necrosis, and dentinal bridge was found in 3 cases, unlike, the formocresol group which had necrosis but no dentinal bridge formation.

CONCLUSION

Based on the results of this study sodium hypochlorite may be a suitable solution for conducting pulpotomy in primary teeth.

Comparison of Antimicrobial Efficacy of IKI and NaOCl Irrigants in Infected Root Canals: An In Vivo Study

INTRODUCTION

Effective debridement of the root canal system with chemical irrigants prior to obturation is the key to long-term success of endodontic therapy. The purpose of this study is to compare the antibacterial activity of 2.5% sodium hypochlorite (NaOCl) and 2% iodine potassium iodide (IKI) solutions as intracanal disinfectant in infected root canals during one-visit endodontic treatment procedure.

MATERIALS AND METHODS

Thirty single-rooted teeth with necrotic pulps in 27 patients were selected according to specific inclusion/exclusion criteria and divided into two random groups. In group I, canals were irrigated with 2.5% NaOCl during instrumentation and in group II canals were initially irrigated with sterile saline during biomechanical preparation and then exposed to a 5-minute final irrigation with 2% IKI. Bacterial samples were taken before treatment (S(1)), and at the end of treatment (S(2)). Mann-Whitney U test was used for analysis.

RESULTS

Bacteria were present in all initial samples. NaOCl was able to significantly reduce the number of colony forming units (CFU) from S(1) to S(2) in approximately 90% of canals. Only 15% reductions in CFUs occurred after irrigation/instrumentation in group II; this degree of disinfection was not statistically significant.

CONCLUSION

According to this study, although root canal irrigation with 2.5% NaOCl could not eradicate all bacteria within the canals; it was significantly superior in comparison with 2% IKI use.

Antimicrobial activity of three root canal irrigants on enterococcus faecalis: an in vitro study

INTRODUCTION

The aim of this study was to compare the antimicrobial effects of 2.5% Sodium hypochlorite (NaOCl), 2% Chlorhexidine Gluconate (CHX) and BioPure MTAD (MTAD) on Enterococcus (E) faecalis-contaminated root canals of human extracted teeth.

MATERIALS AND METHODS

Seventy human intact extracted single-rooted teeth with straight root canal randomly divided into 5 groups: positive control (n=5), negative control (n=5), 2.5% NaOCl (n=20), 2% CHX (n=20), and MTAD (n=20). Each tooth was instrumented using the passive step-back technique hand and rotary instruments. E. faecalis incubated into the canals and grew for 4 weeks. Canals irrigated using three mentioned solutions for 5 minutes. Samples were taken from canal walls and transferred into Brain Heart Infusion (BHI) culture medium and placed in an incubator at 37ºC for 96 hours and bacteriological evaluations were done. Chi- Square test and SPSS software were used for the statistical analysis of the results.

RESULTS

Bacterial growth was seen in only one sample of MTAD group (5%), but in 4 of CHX group (20%) and 5 of NaOCl group (25%). Chi-Square test showed no statistically difference between groups.

CONCLUSION

Based on the results of this study, it seems that all three solutions have acceptable antimicrobial effect on E. faecalis.

A scanning electron microscopic comparison of the cleaning efficacy of endodontic irrigants

INTRODUCTION

The aim of this study was to compare the cleaning efficacy of three irrigants used during and after instrumentation.

MATERIALS AND METHODS

Eighty-four single rooted human teeth were randomly divided into 7 groups, 12 cases each, and canals were instrumented with Mtwo rotary systems. 5.25% sodium hypochlorite, Smear Clear and 17% EDTA were used for irrigation of the canal during and/ or after instrumentation. After completion of instrumentation, all canals were dried with paper points and prepared to examine by scanning electron microscope. All SEM photomicrographs were scored at the coronal, middle and apical thirds of canals in each group. The data were statistically analyzed using Mann-Whitney and Kruskal-Wallis tests.

RESULTS

In the group irrigated with Smear Clear alone, the coronal thirds of the canals were significantly cleaner than middle thirds (P=0.013) and apical thirds (P=0.028). There were less smear layer in the coronal thirds compared to apical thirds (P=0.047) in the group irrigated with Smear Clear and NaOCl alternately .There were significantly more smear layer in the apical thirds compared to coronal thirds (P<0.001) and middle thirds (P=0.007) in the group that Smear Clear and NaOCl were used as final irrigations. There was not any significant difference between three-thirds of the canals in other groups. Comparison of the all groups showed a statistically significant difference (P<0.001) in the amount of debris and smear layer remaining at all three levels of the canals.

CONCLUSION

The findings of this study suggested that a final rinsing by combination of a chelating agent like EDTA or Smear Clear and NaOCl is necessary to obtain favorable clean wall of root canals.

Comparison of two intracanal irrigants' effect on flare-up in necrotic teeth

INTRODUCTION

The aim of this study was to compare the efficacy of two irrigants on decreasing the pain and swelling at different times after treatment of necrotic pulp.

MATERIALS AND METHODS

Fifty patients with single canal tooth and necrotic pulp were selected and divided into two groups, twenty-five in each. Rotary files were used for preparing the canals and 0.2% chlorhexidine gluconate and 2.5% sodium hypochlorite were used for irrigation of canals. Then canals were filled by lateral condensation technique. A questionnaire was given to patients asking for the level of their pain and swelling. The patients were followed for 48h. Visual Analogue Scale (VAS) was used for determination of pain degree. The scale with 4 levels was used for measurement of the intensity of swelling. The data were statistically analyzed using Mann-Witney and Kruskal-Wallis tests.

RESULTS

The research showed no significant difference between irrigant solutions in decreasing the amount of pain and swelling after endodontic treatments. No significant relationship was detected between the incidence of pain with swelling, age, and sex. Flare-up in maxilla was more than mandible.

CONCLUSION

According to results of this in vivo study it was concluded that efficacies of 0.2% chlorhexidine gluconate and 2.5% NaOCl are the same.