An evaluation of antibacterial efficacy of 3% sodium hypochlorite, high-frequency alternating current and 2% chlorhexidine on Enterococcus faecalis: An in vitro study

Comparison of ultrasonic versus side-vented needle irrigation for reductions in bacterial growth and postoperative pain: A randomized controlled trial

Background

Postoperative pain affects 16%-25% of root canal therapy patients. The irrigating system and irrigants used should reduce bacterial load without irrigant extrusion beyond the root canal apex, potentially reducing postoperative pain and discomfort.

Aim

This study aims to compare the effects of passive ultrasonic irrigation and side-vented needle irrigation on postoperative pain and bacterial load in single-rooted teeth with pulp necrosis.

Materials and Methods

Eighty patients with pulpal necrosis in single-rooted teeth were randomly categorized into two groups (n = 40 each): Group A (side-vented needle irrigation) and Group B (passive ultrasonic irrigation). Bacterial samples were collected using sterile paper points after initial access cavity preparation (S1) and standard endodontic instrumentation + irrigation (S2). Bacterial growth was assessed on MacConkey and blood agar. Pain was recorded 30 min preoperatively and 6, 12, 24, and 48 h postoperatively.

Statistical Analysis Used

Chi-square test, independent t-test and paired t-test.

Results

Irrigation with Irrisafe tips showed increased number of bacteria-free samples and a significant reduction in postoperative pain (at the 6 and 12 h time-points) when compared to side-vented needle.

Conclusions

Passive ultrasonic irrigation with Irrisafe tips may be more effective than side-vented needle irrigation in reducing postoperative pain and intracanal bacterial load in patients undergoing endodontic treatment.

Cauterization of Narrow Root Canals Untouched by Instruments by High-Frequency Current

The mechanical removal of bacteria is fundamental to the treatment of infected root canals, but complete sterilization of biofilms tends not to extend to uninstrumented areas. However, during electrical conduction to a root canal filled with a conductor, the higher impedance where the root canal is narrower generates Joule heat that may result in a large temperature increase and sterilization. The effect of a high-frequency electric current on the wall of a simulated narrow root canal was investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Simulated root canals, 0.1 mm in diameter, were prepared in dentine blocks. The root canal wall was treated with Plank-Rychlo solution for 5 min to create a decalcified layer. The simulated root canal was filled with either saline or NaClO, and 150 or 225 V at 520 kHz was applied for 0 s, 1 s, or 5 s. As the conduction time increased, and when the saline was replaced with NaClO, the proportion with a flat decalcified surface decreased, dentinal tubules and a lava-like morphology were significantly more evident on SEM (p < 0.01), and EDS showed significant decreases in carbon and oxygen and increases in calcium (p < 0.01). It was concluded that filling uninstrumented root canals with NaClO and using electrical conduction for 5 s could incinerate and eliminate the organic material of the root canal wall. The application of high-frequency electric current may lead to the cure of many cases of persistent apical periodontitis.

Comparative evaluation of efficacy of three single file retreatment systems for removal of gutta percha and assessment of root canal transportation - An In Vitro study

Background

In comparison to multiple file systems, recent advancements in single file retreatment systems had reduced the working time and ease of operation for clinicians.

Aim

To compare the efficacy of retreatment systems compared with hand instrumentation, by evaluating their removal efficacy, time required for retreatment and assessment of canal transportation.

Methods and Material

Forty premolars were instrumented using ProTaper Gold gold files. Post instrumentation, scan was taken, obturated using warm vertical compaction technique, and stored in artificial saliva for three months and randomly divided into four groups for retreatment. Hand instrumentation (Hi), Neoniti (Nn), Mtwo R (Mt), WaveOne Gold (Wg). Post retreatment, scan was taken. Teeth were sectioned longitudinally and photographed under the stereomicroscope. Retreatment time was recorded, and canal transportation was calculated.

Statistical Analysis

The results were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post hoc test at 95% confidence level.

Results

The retreatment time was significantly longer in the Hi group. Within the test groups, a significantly longer time has been taken by Wg (p < 0.05) compared to Mt and Nn. There was no difference in the canal transportation between the single file systems at 3 mm, 6 mm and 9 mm from the apex, there was statistically significant higher transportation for the Hi group at 9 mm from the apex (p < 0.05).

Conclusions

All techniques were effective in removal of filling material with minimal canal transportation. Wg system was shown to increased time compared to Nn and Mt systems. Hi group was slowest with maximum canal transportation at 9 mm from the apex.

Efficiency of a digital electrofulguration system in contaminated root canals in vitro

Decontamination of the root canal (RC) system is essential for successful endodontic therapy. In this in vitro study, it was evaluated the disinfection potential of an electrofulguration device, the Endox® Endodontic System (EES), in RC infected with Enterococcus faecalis. Sixty-five human lower premolars were instrumented with MTwo® system. The specimens were distributed into six experimental groups (n = 10), according to the irrigation protocol: 2% chlorhexidine gel (CHX); CHX + EES; 5.25% sodium hypochlorite (NaOCl); NaOCl + EES; saline solution (SS); and SS + EES. Five specimens were untreated (control). RC samples were collected before (C1) and after EES treatment (C2), after chemo-mechanical preparation (CMP) (C3), and after final EES treatment (C4). All samples were plated for colony forming units (CFU/mL) onto solid media. The data were analyzed by Wilcoxon and Friedman tests for intragroup comparisons and by Kruskal Wallis test followed by Dunn's test for intergroup comparisons (α = 0.05). Treatment with the EES did not significantly reduce the number of CFU/mL as compared to baseline levels (C1 vs. C2, p> 0.05). After CMP (C3), all groups showed a significantly reduced amount of CFU/mL (p <0.05), with no difference between CHX- and NaOCl-treated samples (p >0.05). Lastly, treatment with the EES following CMP (C4) did not significantly reduce the amount of CFU/mL (C3 vs. C4, p> 0.05). To conclude, the use of the Endox® Endodontic System did not result in considerable bacterial reduction at all operative times, while treatment with NaOCl and CHX was equally efficient for this purpose.

Antimicrobial efficacy of cordless sonic or ultrasonic devices on Enterococcus faecalis-infected root canals

AIM

The aim of the present study was to evaluate the immediate and residual antimicrobial activity of cordless sonic or ultrasonic devices on Enterococcus faecalis (E faecalis)-infected teeth.

METHODS

A total of 140 single-rooted extracted teeth with E faecalis were grouped as follows (N = 15): conventional syringe irrigation with 3% sodium hypochlorite activated by ultrasonic device (group 1) or cordless ultrasonic device (group 2), EndoActivator (group 3) or without activation (group 4), conventional syringe irrigation with sterile bi-distilled water and ultrasonic device (group 5), EndoUltra (group 6), EndoActivator (group 7), or without activation (group 8). The remaining 20 teeth were used for positive and negative controls. Colony-forming units (CFU) and turbidity were recorded from bacteriological samples taken before and after irrigation and after 24 hours of re-incubation. Data were statistically analyzed using Student's t test, Mann-Whitney test, Kruskal-Wallis test, and Dunn's multiple comparison tests (P < .05).

RESULTS

Groups 1 and 2 showed higher antimicrobial efficacy than groups 3 and 4 (P < .05). No bacteria reduction was found in groups 5-8 (P > .05). After 24 hours, regrowth of bacteria was not significantly different for all groups (P > .05).

CONCLUSIONS

Ultrasound produced lower CFU and turbidity after treatment and after re-incubation of 24 hours than sonic or no activation.

Evaluation of Antibacterial Efficiency of Different Root Canal Disinfection Techniques in Primary Teeth

BACKGROUND

A successful primary root canal treatment depends on effective shaping and cleaning the root canal system and finally filling it with a hermetic sealer. Clinically, roots of primary teeth are difficult to shape and the irrigation/disinfection protocol has great importance on prognosis.

OBJECTIVE

The present study evaluated the antibacterial efficiency of Endosafe (Orangedental GmbH & Co. KG), photo-activated disinfection (PAD; Orangedental GmbH & Co. KG), diode laser (Epic 10; Biolase, Inc.), ozone (O₃, Ozonytron; Biozonix, München, Germany), and sodium hypochloride applications in primary root canals that were infected with Enterococcus faecalis after standard mechanical instrumentation.

METHODS

The study was conducted on roots of 100 human primary molar teeth, which were extracted due to excessive caries. The roots were divided in 5 groups with 15 roots in each root disinfection protocol. In addition, 15 samples and 10 samples served as positive and negative controls, respectively. The Shapiro-Wilk test, the Kruskal-Wallis test and then by post hoc group comparisons with the Bonferroni-adjusted Mann-Whitney U test (unpaired observations) was used.

RESULTS

Sodium hypochlorite (NaOCl) exhibited the highest antibacterial effect (0 colony-forming units per mL). Diode laser irradiation was statistically more effective than the ozone, PAD, and Endosafe groups (p < 0.001). Endosafe, PAD, and ozone groups showed similar antibacterial effect (p > 0.05). Although not statistically significant, the Endosafe was more effective in reducing the bacterial count when compared with ozone and PAD.

CONCLUSIONS

The five tested irrigation systems were shown to be effective in disinfection of the E. faecalis-contaminated primary root canals and best results were obtained with 2.5% NaOCl and diode laser.

Effect of Biomineralization Ability on Push-out Strength of Proroot Mineral Trioxide Aggregate, Mineral Trioxide Aggregate Branco, and Calcium Phosphate Cement on Dentin: An In vitro Evaluation

CONTEXT

Biomineralization is a process which leads to the formation of an interfacial layer with tag-like structures at the cement-dentin interface. It is due to interaction of mineral trioxide aggregate (MTA) and Portland cement with dentin in phosphate-buffered solution (PBS). This study is aimed to evaluate the effect of influence of biomineralization process on push-out bond strength of ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK, USA), MTA Branco (Angelus Soluc¸o˜es Odontolo´gicas, Londrina, PR, Brazil) and calcium phosphate cement (BioGraft CPC).

AIM

The aim of this study was to evaluate the effect of biomineralization process on the push-out strength of ProRoot MTA, MTA Branco, and CPC after mixing with 0.2% chlorhexidine gluconate solution (0.2% CHX) and 2% lidocaine solution (2% LA) on the bond strength of MTA-dentin.

MATERIALS AND METHODS

Dentin discs with uniform cavities were restored with ProRoot MTA, MTA Branco, and calcium phosphate cement after mixing with 0.2% CHX solution and 2% lidocaine solution. The samples were uniformly distributed into two groups. Experimental group being immersed in PBS solution and control group being immersed in saline for 2 months. Instron testing machine (Model 4444; Instron Corp., Canton, MA, USA) was used to determine the bond strength.

STATISTICAL ANALYSIS USED

A two-way analysis of variance and post hoc analysis by Bonferroni test.

RESULTS

All samples immersed in experimental group displayed a significantly greater resistance to displacement than that observed for the samples in control group (P < 0.05). MTAs displayed a significantly greater resistance to displacement than calcium phosphate cements.

CONCLUSION

The main conclusion of this study was that the push-out bond strength of the cements, mainly the MTA groups, was positively influenced by the biomineralization process.

Análise de dois métodos de desinfecção de condutos radiculares após preparo para pinos: proposta de protocolo protético: estudo in vitro

Resumo Introdução Quando existe perda de suporte coronário e ainda desgaste adicional devido a tratamento endodôntico, muitas vezes, é necessária a utilização de um retentor intrarradicular que devolva a retenção para a restauração, reestabelecendo estética e função às estruturas dentárias perdidas. A cadeia asséptica mantida durante a endodontia pode ser quebrada com alguns procedimentos clínicos. Objetivo Testar um protocolo de desinfecção por E. faecalis dos condutos radiculares, nas etapas de confecção de um retentor intrarradicular, desmistificando que a quebra da cadeia asséptica e o surgimento de infecções radiculares sejam provenientes da reabilitação protética. Material e método 50 dentes unirradiculares com endodontia concluída foram desobturados, tiveram seus condutos preparados para retentor intrarradicular e foram contaminados por Enterococcus faecalis. Os dentes foram separados em três grupos de acordo com a substância desinfectante: G1-solução fisiológica (n=10), G2- hipoclorito de sódio 2,5% (n=20), G3- clorexidina 2% (n=20). Em seguida, foi feita a desinfecção do conduto, secagem e análise da eficácia da solução. A avaliação da presença da bactéria foi feita através do cultivo em caldo Brain Heart Infusion, pelo método da turvação, e posterior identificação pelo meio Ágar Bílis-Esculina. A análise estatística foi feita pelo método do quiquadrado em tabulação cruzada, onde p<0,0001. Resultado Observou-se a inibição bacteriana de 100% em G2 e G3 e crescimento bacteriano de 100% em G1. Conclusão O emprego das substâncias avaliadas nas etapas protéticas de finalização de um retentor intrarradicular, como protocolado por esta pesquisa, é capaz de manter a cadeia asséptica sem interferir no sucesso da reabilitação protética.

Evaluation of Antibacterial Efficacy of Photodynamic Therapy vs. 2.5% NaOCl against E. faecalis-infected Root Canals Using Real-time PCR Technique

Background

Bacteria like E. faecalis can produce intra- and extra-radicular biofilms. Theoretically, the adjustable penetration ability of lasers enables better access to root canal system. Therefore the aim of the present study was to compare the ability of photoactivated laser and 2.5% NaOCl irrigation solution to eliminate E. faecalis from the root canals by real-time PCR technique.

Material and Methods

Sixty extracted human upper central incisors were selected and sterilized in an autoclave. The root canals were infected with E. faecalis (PTCC 1237, Persian Type Culture Collection, Iran) and then incubated for 24 hours. The samples were randomly divided into 3 groups. No intervention was made in the control group (group 1). In group 2, laser therapy was performed with a power of 100 mW by diode laser for 120 seconds. In group 3, the canals were irrigated with 5 mL of 2.5% NaOCl; then all the samples were sonicated in 15 mL of normal saline in test tubes in order to isolate the bacteria. DNA extraction was performed followed by real-time PCR technique for all the samples.

Results

Inhibition of bacterial growth in all the experimental samples was significantly more than that in the control group. There was a significant difference between photodynamic therapy and 2.5% NaOCl. The effect of NaOCl in all the samples was better than photodynamic therapy. The results of the mean CT (cyclic threshold) were 40, 30.2 and 15.35 for 2.5% NaOCl, photodynamic therapy and control group, respectively.

Conclusions

Based on the results of this experimental study, 2.5% NaOCl eliminated E. faecalis from infected root canals more effectively compared to photodynamic therapy.

Key words:Photoactivated laser, Enterococcus faecalis, antibacterial agents, sodium hypochlorite.

The effect of chlorhexidine on the push-out bond strength of calcium-enriched mixture cement

INTRODUCTION

The aim of this in vitro study was to evaluate the effect of 2% chlorhexidine (CHX) on the push-out bond strength (BS) of calcium-enriched mixture (CEM) cement.

METHODS AND MATERIALS

Root-dentin slices from 60 single-rooted human teeth with the lumen diameter of 1.3 mm were used. The samples were randomly divided into 4 groups (n=15), and their lumens were filled with CEM cement mixed with either its specific provided liquid (groups 1 and 3) or 2% CHX (groups 2 and 4). The specimens were incubated at 37(°)C for 3 days (groups 1 and 2) and 21 days (groups 3 and 4). The push-out BS were measured using a universal testing machine. The slices were examined under a light microscope at 40× magnification to determine the nature of bond failure. The data were analyzed using the two-way ANOVA. For subgroup analysis the student t-test was applied. The level of significance was set at 0.05.

RESULTS

After three days, there was no significant difference between groups 1 and 2 (P=0.892). In the 21-day specimens the BS in group 3 (CEM) was significantly greater than group 4 (CEM+CHX) (P=0.009). There was no significant difference in BS between 3 and 21-day samples in groups 2 and 4 (CEM+CHX) (P=0.44). However, the mean BS after 21 days was significantly greater compared to 3-day samples in groups 1 and 3 (P=0.015). The bond failure in all groups was predominantly of cohesive type.

CONCLUSION

Mixing of CEM with 2% CHX had an adverse effect the bond strength of this cement.

The effect of various topical peri-implantitis antiseptics on Staphylococcus epidermidis, Candida albicans, and Streptococcus sanguinis

OBJECTIVE

Although peri-implantitis has presented an ever increasing problem in modern dentistry, satisfying therapeutic strategies or scientifically based treatment recommendations are still not available. The main object of the present study was to evaluate the antibacterial efficacy of six different topical antiseptics on three test microorganisms attached to titanium implant specimens.

MATERIAL AND METHODS

For biofilm formation, plane titan specimens were incubated either in Candida albicans, Streptococcus sanguinis, or Staphylococcus epidermidis for 2h. The specimens were then treated with different topical antiseptics for 60s (sodium hypochlorite 1.0%, hydrogen peroxide 3.0%, chlorhexidine gluconate 0.2%, citric acid 40.0%, Plax, or Listerine) and with sterile saline as control. Remaining vital fungi were quantified by means of a bioluminometric assay and the bacterial load and the viability of adhering S. epidermidis and S. sanguinis by live or dead cell labelling in combination with fluorescence microscopy.

RESULTS

Sodium hypochlorite was effective against all three species, whereas hydrogen peroxide was solely effective against C. albicans. CHX and Listerine showed antimicrobial activity against S. sanguinis and C. albicans and citric acid and Plax against both tested bacteria.

CONCLUSIONS

None of the tested antimicrobial agents, except for sodium hypochlorite, showed a significant in vitro effect on all three test microbes. Considering the possible toxicity of sodium hypochlorite, none of the tested - and so far widely used - antiseptics showed any broad-spectrum antimicrobial effect and could therefore not be recommended for the topical disinfection and detoxification of infected implant surfaces.