In vivo evaluation of microbial reduction after chemo-mechanical preparation of human root canals containing necrotic pulp tissue

Principle and antimicrobial efficacy of laser-activated irrigation: A narrative review

In the last two decades, the activation of root canal irrigants with pulsed lasers as an adjunct in root canal treatment has become increasingly popular. This narrative review explains the physical basics and the working mechanism of laser-activated irrigation (LAI), explores the parameters influencing LAI efficacy, considers historical evolutions in the field and summarizes laboratory and clinical evidence with emphasis on the antimicrobial action of LAI. Cavitation is the driving force behind LAI, with growing and imploding vapour bubbles around the laser tip causing various secondary phenomena in the irrigant, leading to intense liquid dynamics throughout the underlying root canal. High-speed imaging research has shown that laser wavelength, pulse energy, pulse length and fibre tip geometry are parameters that influence this cavitation process. Nevertheless, this has not resulted in standardized settings for LAI. Consequently, there is significant variability in studies assessing LAI efficacy, complicating the synthesis of results. Laboratory studies in extracted teeth suggest that, with regard to canal disinfection, LAI is superior to conventional irrigation and there is a trend of higher antimicrobial efficacy of LAI compared to ultrasonic activation. Clinical evidence is limited to trials demonstrating similar postoperative pain levels after LAI versus no activation or ultrasonic activation. Clinical evidence concerning the effect of LAI on healing of apical periodontitis as yet is scarce.

Disinfectant effectiveness of chlorhexidine gel compared to sodium hypochlorite: a systematic review with meta-analysis

This study aimed to compare the disinfectant ability of chlorhexidine (CHX) gel and sodium hypochlorite (NaOCl). Systematic searches were conducted from inception until December 8th, 2022 (MEDLINE/PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Grey Literature databases). Only randomized clinical trials were included. The revised Cochrane risk of bias tools for randomized trials were used to assess the quality of studies. Meta-analyses were performed. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation tool. Six studies were included. Five had a low risk of bias and 1 had some concerns. Three studies assessed bacterial reduction. Two were included in the meta-analysis for bacterial reduction (mean difference, 75.03 [confidence interval, CI, -271.15, 421.22], p = 0.67; I2 = 74%); and 3 in the meta-analysis for cultivable bacteria after chemomechanical preparation (odds ratio, 1.03 [CI, 0.20, 5.31], P = 0.98; I2 = 49%). Five studies assessed endotoxin reduction. Three were included in a meta-analysis (mean difference, 20.59 [CI, -36.41, 77.59], p = 0.48; I2 = 74%). There seems to be no difference in the disinfectant ability of CHX gel and NaOCl, but further research is necessary.

Microbiological Effectiveness of Sodium Hypochlorite Gel and Aqueous Solution When Implemented for Root Canal Disinfection in Multirooted Teeth: A Randomized Clinical Study

The aim of endodontic therapy is to use various antimicrobial medications for proper cleaning and shaping to create an environment free of microorganisms by eradicating as many as possible from the root canal space. Even although it is a gold standard irrigant, sodium hypochlorite (NaOCl) is known for its cytotoxic effects on vital periapical tissues, making its higher concentrations inappropriate for use in conditions such as wide, underdeveloped, or damaged apices and in cases of perforations. Consequently, if it is ascertained that a gel form of sodium hypochlorite has equivalent antibacterial activity to the aqueous solution form, it could be employed in such situations. The aim of this study was the microbiologic evaluation of 5.25% sodium hypochlorite gel and aqueous solution as root canal disinfectants in multirooted teeth with primary endodontic lesions. Following ethical approval and CTRI registration, 42 patients who gave their consent and had multirooted teeth with pulpal necrosis and asymptomatic apical periodontitis were considered for the study. Following the opening of the access, pre-endodontic build up in case of class-II cavities and working length determination, a pre-operative sample (S1), which was regarded as the pre-operative microbial load of that canal, was acquired from the largest canal using a sterile paper point while maintaining strict isolation and disinfection. The computer randomization approach was used to divide the teeth into two groups at random just before beginning of chemo-mechanical preparation: Group A (n = 21)-canal disinfection with 5.25% sodium hypochlorite gel; Group B (n = 21)-canal disinfection with 5.25% sodium hypochlorite aqueous solution. Following the canal disinfection, a post-operative (S2) sample which was regarded as the postoperative microbial load of that canal was collected from the same canal using a sterile paper point. The Colony-Forming Units (CFUs) for the S1 and S2 samples were determined after 48 h aerobic incubation on Brain Heart Infusion (BHI) agar plates. The patients and the microbiologist were blinded throughout the procedure. Using SPSS 20.0 software (USA), the Shapiro-Wilk test and the Lilliefors Significance Correction were used for normality, followed by the Mann-Whitney U test which was used to compare the CFU difference (×10⁵) between the two groups. A p value of <0.05 was perceived as statistically significant. The mean colony-forming units count difference between the 5.25% sodium hypochlorite gel and aqueous solution groups did not differ in a manner that was statistically significant (p = 0.744). In multirooted teeth with primary endodontic lesions, the 5.25% sodium hypochlorite gel and the aqueous solution demonstrated comparable antimicrobial effectiveness when implemented as root canal disinfectants.

Antimicrobial efficacy of sodium hypochlorite, saline, and Er, Cr:YSGG laser-assisted disinfection in root canal treatment of primary molars: An in vivo study

Aim

The aim of the study was to compare the antimicrobial efficacy of sodium hypochlorite (NaOCl), Saline, and Er, Cr:YSGG laser-assisted disinfection through microbiological analysis in root canal treatment of primary molars.

Materials and Methods

Forty-five primary teeth were selected for this study as per the inclusion and exclusion criteria in the age group of 4-8 years and then randomly allocated to Three Groups A, B, and C. In Group A, during root canal treatment, irrigation was done using NaOCl, in Group B, laser-assisted disinfection was done using Er, Cr:YSGG laser, and in Group C, saline was used as an irrigating agent. This was followed by obtaining pre- and postirrigation samples from the canals for microbiological investigation in all the groups. Data analysis was performed using Statistical Package for the Social Science-21 (SPSS-21).

Results

NaOCl was more effective against aerobic bacteria while Er, Cr:YSGG laser was more effective against anaerobic bacteria when used for disinfection in root canal treatment. There was a significant difference among the three groups (P > 0.05).

Conclusion

The study showed that NaOCl and Er, Cr:YSGG laser have antimicrobial effects when used for disinfection in root canal treatment of primary teeth. Moreover, the study also shows that Er, Cr:YSGG laser may be used as a valuable tool for laser-assisted disinfection in root canal treatment of primary teeth.

Ex-vivo study about antimicrobial effectiveness of phytic acid against Enterococcus faecalis into root canals

BACKGROUND

Endodontic failure is due to the persistence of microorganisms, especially Enterococcus faecalis, which have become resistant to disinfection measures. Sodium hypochlorite has been traditionally used, whereas phytic acid, a natural irrigant, needs to be further investigated.

METHODS

This ex-vivo study compared the antibacterial effectiveness of 0.9% saline solution, 5% sodium hypochlorite and 5% phytic acid against Enterococcus faecalis ATCC 29212 into the apical root canal third of 96 single-rooted extracted teeth, after 1-minute push-and-pull irrigation - a basic irrigation technique. Survived microorganisms were evaluated both through a traditional colony-forming-unit count and introducing the viability PCR, which precisely detects only DNA from intact cells: dead and damaged cells were excluded thanks to a propidium monoazide dye.

RESULTS

The culture methods showed that 5% sodium hypochlorite (median: 0 CFU/mL) has a significant greater antibacterial effectiveness (P<0.001) compared both to 0.9% saline solution (median: 4.76 CFU/mL) and 5% phytic acid (median: 0.25 CFU/mL). However, 5% phytic acid proved to be significantly more effective (P<0.001) than 0.9% saline solution. The viability PCR did not reveal a significant difference between 5% sodium hypochlorite (median: 4.12×10⁴ survived bacteria) and 0.9% saline solution (median: 8.45×10⁴ survived bacteria). Five percent phytic acid (median: 0.83×10⁴ survived bacteria) was significantly more effective than both 0.9% saline solution (P<0.001) and 5% sodium hypochlorite (P<0.001).

CONCLUSIONS

The findings suggest that 5% phytic acid works against root canal bacteria even with a basic irrigation technique and viability PCR seems to lead to more reliable and sensitive data rather than the culture methods.

Incidence of fracture of ProDesign Logic system instruments: A cross-sectional retrospective study

The aim of the present study was to analyze the incidence of fracture of ProDesign Logic system instruments in endodontic treatments performed by a specialist, in addition to identifying the dental group, arch, and the root canal thirds in which the fractures occurred more frequently. Digital radiographs and medical records were initially analyzed and resulted in the selection of 561 teeth (1302 canals) treated between 2018 and 2020, using the ProDesign Logic system instruments. These data were reassessed to determine the occurrence of fractures and identify the dental group and root canal thirds in which they occurred. Then, the data were statistically analyzed using the Fisher's Exact Test (p < 0.05). The general fracture rates were 8.5 and 3.69%, considering the number of teeth and canals treated, respectively. Mandibular first molars were the teeth most associated with the occurrence of fractures (19.1%). When the arches were compared, there was no statistical difference regarding the number of fractures in the different root canal thirds (p = 0.307). However, they were more frequent in the apical third in both arches (p = 0.000). The incidence of fracture of ProDesign Logic system instruments was relatively high and occurred more frequently in the apical third of molars.

A critical analysis of research methods and experimental models to study irrigants and irrigation systems

Irrigation plays an essential role in root canal treatment. The purpose of this narrative review was to critically appraise the experimental methods and models used to study irrigants and irrigation systems and to provide directions for future research. Studies on the antimicrobial effect of irrigants should use mature multispecies biofilms grown on dentine or inside root canals and should combine at least two complementary evaluation methods. Dissolution of pulp tissue remnants should be examined in the presence of dentine and, preferably, inside human root canals. Micro-omputed tomography is currently the method of choice for the assessment of accumulated dentine debris and their removal. A combination of experiments in transparent root canals and numerical modeling is needed to address irrigant penetration. Finally, models to evaluate irrigant extrusion through the apical foramen should simulate the periapical tissues and provide quantitative data on the amount of extruded irrigant. Mimicking the in vivo conditions as close as possible and standardization of the specimens and experimental protocols are universal requirements irrespective of the surrogate endpoint studied. Obsolete and unrealistic models must be abandoned in favour of more appropriate and valid ones that have more direct application and translation to clinical Endodontics.

Irrigating Solutions and Activation Methods Used in Clinical Endodontics: A Systematic Review

Background

Ex vivo and in vitro studies have demonstrated the effectiveness of some irrigation protocols in reducing the bacterial load in the root canal system. However, standardized protocols have not yet been defined for the real clinical context due to many irrigation procedures available.

Objective

To evaluate the clinical endodontic protocols and limitations of irrigating solutions in the disinfection of the root canal system in patients with apical periodontitis.

Methods

PubMed, Scopus, Embase, Web of Science, and Cochrane databases were searched for randomized controlled trials (RCT) published until January 2021. Hand searching was also performed. Studies focused on evaluating the effectiveness of irrigating solutions and/or irrigation activation methods in reducing the bacterial load in the root canal system were considered. The Cochrane risk-of-bias tool for randomized trials (RoB2) was used to assess the quality of the studies.

Results

Four hundred and twenty eight published articles were identified. After removing the duplicate studies and analyzing full texts, seven RCTs were selected. Two studies compared pure NaOCl with some combination of NaOCl with HEDP and MTAD. Two studies analyzed the antibacterial efficacy of NaOCl and chlorhexidine (CHX). Three studies compared conventional needle irrigation with different irrigation activation methods (PUI, XP-endo finisher, F-file activator, EndoVac activator). The review attained a satisfactory methodology. The main results of each included study were described.

Discussion

Activation methods provide significantly higher biofilm reduction than conventional needle irrigation methods. Combinations of NaOCl with different chelating agents were ineffective in terms of antimicrobial, but it could potentially increase the risk of irrigant extrusion. However, the irrigating protocols were not carefully detailed, especially those regarding the irrigants application time or total volume. The existing literature lacks high-quality studies. The level of evidence is moderate.

Conclusions

The available data is too heterogeneous to compare and identify the superiority of specific valuable irrigation protocols in each clinical context. Application time, volume, and activation methods should be standardized to determine the optimal irrigating procedures to reduce the bacterial load and ensure higher predictability of the endodontic treatment.

Systematic Review Registration

(https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=218555), PROSPERO registration: CRD42020218555.

Comparative evaluation of chlorhexidine and cetrimide as irrigants in necrotic primary teeth: An In vivo study

Context:

Disinfection of the root canal system by biomechanical preparation and profuse irrigation is especially important in primary teeth due to its complex pulp canal anatomy. Appropriate selection of irrigating solution should be done in terms of tissue dissolving capacity, antibacterial efficacy, and palatability when treating pediatric cases.

Aim:

The aim of the study was to compare the antibacterial efficacy of 2% chlorhexidine (CHX), 0.2% cetrimide (CTR), and 0.2% CHX + 0.2% CTR against anaerobic bacteria and to test the influence of CTR added to CHX on its antibacterial action.

Materials and Methods:

Seventy-five teeth that were selected for the study were divided into three groups: Group I (2% CHX), Group II (0.2% CTR), and Group III (0. 2% CHX + 0.2% CTR). Samples collected before and after irrigation were immediately processed and microbial growths were quantified.

Statistical Analysis:

Intergroup comparison was done using one-way analysis of variance and Newman–Keuls multiple post hoc procedures and intragroup comparison was done using paired t-test.

Results:

When the mean values of Group I were compared with Group II, the data were statistically not significant (P = 0.2341), whereas Group I showed a significant difference when compared with Group III (P = 0.0107). When the mean values of Group II and Group III were compared, the data were found to be statistically not significant (P = 0.0805).

Conclusion:

The efficacy of 2% CHX was found to be slightly superior when compared with that of 0.2% CTR, but the difference was not statistically significant. However, a significant difference was found between 2% CHX and combination irrigants.

Present status and future directions - microbiology of endodontic infections

Apical periodontitis has a microbial aetiology and is one of the most common inflammatory diseases that affect humans. Fungi, archaea and viruses have been found in association with apical periodontitis, but bacteria are by far the most prevalent and dominant microorganisms in endodontic infections. Bacterial infection of the root canal system only occurs when the pulp is necrotic or was removed for previous treatment. In some specific cases, including acute and chronic abscesses, the bacterial infection may reach the periradicular tissues. Intracanal bacteria are usually observed as sessile multispecies communities (biofilms) attached to the dentinal root canal walls. Infection in the main root canal lumen can spread to other areas of the root canal system. Although more than 500 bacterial species have been detected in endodontic infections, a selected group of 20 to 30 species are most frequently detected and may be considered as the core microbiome. There is a high interindividual variability in the endodontic microbiome in terms of species composition and relative abundance. Obligate anaerobic species are more abundant in the intraradicular bacterial communities of teeth with primary apical periodontitis, while both anaerobes and facultatives dominate the communities in post-treatment apical periodontitis. Bacterial interactions play an essential role in determining the overall virulence of the community, which has been regarded as the unit of pathogenicity of apical periodontitis. This article reviews the microbiologic aspects of endodontic infections and provides perspectives for future research and directions in the field.

Assessing Macrophage Polarization in Nanoparticle-Guided Wound Repair Using a Lipopolysaccharide Contaminated Intraosseous Model

INTRODUCTION

Macrophages regulate the processes of inflammation and tissue regeneration/repair through their plasticity and phenotypes of different activation states. Previous studies have shown that disinfection of lipopolysaccharide (LPS)-contaminated dentin with photoactivated rose bengal-functionalized chitosan nanoparticles (CSRBnps) in vivo supported neotissue formation without signs of inflammation and root resorption. The aim of this study was to understand the mechanism underlying CSRBnp-guided attenuation of inflammation in LPS-contaminated dentin using macrophage polarization as an indicator of inflammation and repair.

METHODS

To quantify the polarized macrophage populations, M1/M2-specific surface markers CD68, CD80, and CD206 and transcriptional factors signal transducer and activator of transcription (STAT) 1, STAT3, and STAT6 were determined using immunohistochemistry among previously obtained root specimens implanted into mandibles of guinea pigs for 4 weeks. In group 1, the canals were not inoculated; in group 2, the canals were inoculated with Pseudomonas aeruginosa LPS; in group 3, the canals were inoculated and disinfected with sodium hypochlorite; in group 4, the canals were inoculated and disinfected with sodium hypochlorite and calcium hydroxide; and in group 5, the canals were inoculated and disinfected with sodium hypochlorite, and CSRBnps (300 μg/mL) with photoactivation (λ = 540 nm, 40 J/cm²) were analyzed.

RESULTS

An increased expression of M2-specific markers was observed in the group treated with CSRBnps compared with the groups treated with either conventional or no root canal disinfection. A statistically significant population of macrophages expressing both M1- and M2-specific markers was observed in all the tested groups.

CONCLUSIONS

Disinfection of LPS-contaminated dentin with CSRBnps demonstrated M2-type polarization of macrophages, which corresponded to repair and neotissue formation.

Effect of Irrigants and Irrigating Devices on Disinfection of Root Canal System: A Systematic Review

Aim:

The effective delivery of irrigants into the inaccessible areas of the root canal system is the prerequisite for a proper disinfection of the root canal system. Numerous activation devices that can provide effective delivery of the irrigant and aid in the success of the root canal treatment are available. The activation of irrigants has claimed to be effective in in vitro and clinical trials. Hence, the present systematic review aims to analyze the effect of irrigants and irrigating devices in disinfecting the root canal system.

Materials and Methods:

A literature search was undertaken in PubMed, Cochrane, Web of Science, and Scopus databases. The inclusion criteria included clinical trials, both in vivo and ex vivo. The exclusion criteria included animal studies, textbooks, review articles, and case reports. The patients who required endodontic treatment along with the activation of irrigants were chosen as participants for the review.

Result:

The search strategy screened around 132 articles, out of which only 10 were selected for the present systematic review. The risk of bias was calculated based on the following scores: 3, high; 2, moderate; and 1, low. In the present systematic review, four articles were categorized into low-risk bias, three articles were classified as moderate risk, and three articles belonged to the high-risk category.

Conclusion:

The present systematic review concluded that the use of a mechanical activation device along with the irrigant will help in better removal of the smear layer and debris from the root canal system, improving the cleanliness and helping achieve more successful endodontic treatment.

Evaluation of the efficacy of a novel antibiotic-steroid paste versus conventionally used intracanal antibiotic pastes and irrigating solutions against a 3-week-old biofilm of Enterococcus faecalis

Introduction

Intracanal medicaments have been used during endodontic regenerative procedures to eradicate endodontic pathogens.

Aims

The aim of our study was (1) to evaluate the antimicrobial efficacy of a novel antibiotic-steroid paste over the regularly used calcium hydroxide (Ca (OH)₂), double antibiotic paste (DAP), and modified triple antibiotic paste (M-TAP) and (2) to check the antimicrobial efficacy of irrigating solutions, Chlorhexidine (CHX), and sodium hypochlorite (NaOCl) against a 3-week-old Enterococcus faecalis (E. faecalis) biofilm.

Materials and Methods

A total of 112 human extracted teeth were contaminated with E. faecalis for a period of 21 days. A novel antibiotic-steroid paste, Ca (OH) ₂, DAP, M-TAP, and a placebo were placed inside the canal, sealed, and incubated in an aerobic environment at 37°C. For irrigating solutions, each prepared sample was immersed in 1 ml of sterile saline for 1 min, followed by irrigating and immersion with 1.5% NaOCl and 2% CHX for 5 min. An antimicrobial assessment was performed at the end of 2 days and 7 days, with seven teeth from each group, for each time interval. Dentin debris collected was transferred to the respective medium for culture. After 24 h, colonies were counted using classical bacterial counting technique as colony-forming units.

Results

Statistical analysis revealed that the novel antibiotic-steroid paste showed a statistically insignificant difference when compared to DAP, which had the highest antimicrobial properties.

Conclusion

This novel functional paste has antimicrobial efficacy comparable with that of DAP.

Antibacterial Activity of Sodium Hypochlorite Gel versus Different Types of Root Canal Medicaments Using Agar Diffusion Test: An In Vitro Comparative Study

Aim

This study aimed to evaluate the antibacterial effect of sodium hypochlorite gel and four types of intracanal medicaments.

Materials and Methods

The agar diffusion method was used to evaluate the antibacterial effect of five medicaments (sodium hypochlorite gel (NaOCl), chlorhexidine gel (CHX), calcium hydroxide paste (CH), Ledermix, and Diapex plus) against Enterococcus faecalis (E. faecalis), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The zone of inhibition around each medicament was measured in millimeters, after 48 hours of incubation at 37°C. The antibacterial effects of medicaments against each microbial strain and the sensitivity of microorganisms towards each medicament were compared using the one-way ANOVA and Games–Howell post hoc tests. The level of significance was set to p < 0.05.

Results

All medicaments showed variable inhibition zones for all bacterial strains except Diapex Plus which showed no antibacterial activity. NaOCl gel exhibited the most significant inhibition zones for all bacterial strains followed by CHX gel, Ledermix, and CH. However, the effect of CHX and CH paste against S. aureus was statistically similar, while the effect of CH against E. faecalis was significantly higher than the Ledermix.

Conclusion

Sodium hypochlorite gel displayed the highest antibacterial activity among tested medicaments and can be recommended as a potent intracanal medicament. Chlorhexidine gel showed a significantly higher antibacterial effect when compared with Ledermix and calcium hydroxide. Calcium hydroxide demonstrated stronger antibacterial activity against E. faecalis than Ledermix. Diapex Plus exhibited no antibacterial effect.

Current uses of chlorhexidine for management of oral disease: a narrative review

Objectives

Chlorhexidine (CHX) is a commonly used antiseptic mouthwash, used by dental practitioners and the public, due to its antimicrobial effects. The aim of this article was to provide a narrative review of current antimicrobial uses of CHX relevant to dentistry in the context of oral diseases, highlighting need for further studies to support its safe and appropriate use.

Study selection, data and sources

Randomised controlled trials, systematic reviews and national (UK and US) guidelines were consulted where available, with search terms for each subject category entered into MEDLINE, PubMed, Google Scholar and the Cochrane database.

Results

Some evidence existed to support adjunctive short-term use of CHX to manage dental plaque, and reduce clinical symptoms of gingivitis, dry socket, as well as reduce aerosolisation of bacteria. However, use must be weighed alongside the less desirable effects of CHX, including extrinsic staining of teeth, antimicrobial resistance to antiseptic agents and the rare, but fatal, allergic reactions to CHX. Conversely, evidence for the effectiveness of chlorhexidine to manage or prevent periodontitis, dental caries, necrotising periodontal diseases, peri-implantitis, and infections associated with extraction and aerosolised viruses remains less certain.

Conclusions

The use of CHX in dentistry and oral healthcare continues to be widespread and thus it is important that dental practitioners understand that, based on its differential mechanisms of action on different microbes, appropriate clinical and dental use of CHX should be oral disease specific. However, further scientific and clinical research is required before full recommendations can be made.

Evaluation of in vitro biofilm elimination of Enterococcus faecalis using a continuous ultrasonic irrigation device

This study sought to evaluate biofilm elimination using the HBW Ultrasonic Ring based on continuous ultrasonic irrigation. Forty-five premolars and molars with complex curvatures were included. An Enterococcus faecalis biofilm was established for 30 days on the extracted teeth. The teeth were then stratified into three experimental groups for instrumentation and irrigation (i.e. HBW Ultrasonic Ring, conventional irrigation, and passive ultrasonic irrigation). Pre- and post-instrumentation samples were collected, and reductions of bacterial load were evaluated by McFarland's scale, counting of colony-forming units, and scanning electronic microscopy. The HBW Ultrasonic Ring promoted a higher reduction in bacterial load relative to conventional irrigation (P < 0.05) and a similar reduction compared with passive ultrasonic irrigation (P > 0.05). These results suggest the HBW Ultrasonic Ring is a promising alternative modality for simultaneous instrumentation and irrigation during root canal treatment, achieving an appropriate level of bacterial reduction and allowing the passage of the irrigating solution throughout the entire working length.

Antimicrobial, antibiofilm and cytotoxic effects of a colloidal nanocarrier composed by chitosan-coated iron oxide nanoparticles loaded with chlorhexidine

OBJECTIVES

This study evaluated the antimicrobial and antibiofilm effects of a colloidal nanocarrier for chlorhexidine (CHX) on Candida glabrata and Enterococcus faecalis, as well as tested its cytotoxic effect on murine fibroblasts.

METHODS

Iron oxide nanoparticles (IONPs) were coated with chitosan (CS) and loaded with CHX at 31.2, 78 and 156 μg/mL. Antimicrobial effects were assessed by determining the minimum inhibitory concentration (MIC), using the broth microdilution method, and fractional inhibitory concentration index (FICI). Preformed biofilms (48 h) were treated with different concentrations of the nanocarrier (24 h) and quantified by colony-forming units (CFUs), total biomass and metabolic activity. For cytotoxicity, the viability of L929 cells was evaluated by MTT assay after 24 and 48 h of exposure to the nanocarrier. Data were submitted to ANOVA and Fisher LSD or Tukey post-hoc tests (α = 0.05).

RESULTS

MIC and FICI results showed an indifferent interaction among the components of the nanocarrier for all strains evaluated. CHX alone and nanocarrier containing 156 μg/mL CHX did not differ from each other in reducing the number of CFUs. However, the nanocarrier containing 156 μg/mL CHX promoted the highest reductions in total biofilm biomass and metabolism, surpassing the effect of CHX alone. After 24 and 48 h of exposure, the nanocarrier reduced CHX toxicity to the L929 cell at low concentrations.

CONCLUSION

These findings suggest that the CHX nanocarrier has potential to be used in the control of oral diseases associated with C. glabrata and E. faecalis.

CLINICAL RELEVANCE

CHX has improved the antibiofilm effect and reduced the cytotoxicity (at low concentrations) when conjugated to CS-coated IONPs. This new colloidal formulation has potential as an alternative antimicrobial agent to pure CHX for the control of biofilm-related oral diseases, such as oral candidiasis and endodontic infections.

Debris extrusion during root canal preparation with nickel-titanium instruments using liquid and gel formulations of sodium hypochlorite in vitro

This study compared the amount of apically extruded debris during root canal preparation with three single-file systems using liquid and gel-based formulations of sodium hypochlorite (NaOCl) or distilled water. Seventy-two single-canalled roots were divided into three groups: HyFlex EDM (Coltene-Whaledent); Reciproc Blue (VDW); and F-One Blue (Shanghai Fanta) and then divided into three subgroups: NaOCl liquid (Imicrly), NaOCl gel (Cerkamed Medical) and distilled water. The amount of extruded debris was calculated by determining the dry weight of the debris collected. Data were analysed using Kruskal-Wallis test with Bonferroni correction. Debris extrusion occurred in all subgroups. Both the instrument and the irrigant had an impact. The F-One Blue tended to extrude the least debris, though no significant difference was observed in the pairwise comparisons between instruments. NaOCl liquid resulted in significantly more extruded debris than NaOCl gel or distilled water. The results lead us to conclude that the NaOCl gel reduced debris extrusion compared to NaOCl liquid.

Effects of Contemporary Irrigant Activation Schemes and Subsequent Placement of an Interim Dressing on Bacterial Presence and Activity in Root Canals Associated with Asymptomatic Apical Periodontitis

New tools for activating endodontic irrigants have evolved, yet their impact on root canal disinfection, in comparison to the passive placing of an inter-visit medication, have not yet been fully elucidated. The use of DNA- and rRNA-based methods may cast some new light on this issue, as they allow a comparison to be made between microbial presence and activity. Therefore, the aim of this single-arm intervention trial is to evaluate the antibacterial effect of endodontic procedures using both molecular methods. Root canal samples were obtained from 20 patients with asymptomatic apical periodontitis after each treatment step: access cavity, chemo-mechanical preparation, adjunctive procedures (XP-endo Finisher file and passive ultrasonic irrigation), calcium hydroxide medication, and 2nd-visit root canal preparation. DNA and cDNA from the samples were subjected to quantitative polymerase chain reaction with universal primers for the bacterial 16S rRNA gene. Chemo-mechanical preparation promoted a drastic reduction in bacterial levels and activity, whereas the adjunctive procedures did not make a significant contribution to further disinfection. At the 2nd visit, bacteria were active after the use of calcium hydroxide medication; however, they were significantly reduced after a 2nd-visit preparation. Consequently, the lowest bacterial levels were found at the end of the treatment. This clinical trial, which used an rRNA and rDNA combined approach, confirmed previous studies showing that root canal preparation represents the main strategy for root canal disinfection.

Efficacy of bioactive nanoparticles on tissue-endotoxin induced suppression of stem cell viability, migration and differentiation

AIM

To characterize a lipopolysaccharide (LPS)-treated dentine tissue model (LPS dentine) to analyse the efficacy of polycationic chitosan nanoparticles (CSnp) and/or dexamethasone conjugate chitosan nanoparticles (Dex-CSnp) on the viability/differentiation potential of stem cells from apical papilla (SCAP) when exposed to LPS dentine. A further aim was to understand the effect of macrophage-dependent inflammation on SCAP migration in the presence of LPS dentine.

METHODOLOGY

A total of 88 dentine slabs were used. TOF-SIMS analysis was performed amongst the LPS-treated and untreated dentine groups (n = 2/group). The study was conducted using four dentine groups: no treatment (control); LPS treatment only; LPS treatment followed by CSnp conditioning; and LPS treatment followed by Dex-CSnp conditioning groups. SCAP adherence, viability, differentiation and biomineralization potential on dentine from different groups were studied using fluorescent and scanning electron microscopy. Inflammation by macrophages in response to LPS dentine was quantified, and effect on SCAP migration was analysed. Statistical analysis was performed using Student's t-test with a significance level of P < 0.05.

RESULT

TOF-SIMS analysis confirmed LPS contamination. LPS dentine affected SCAP viability but not adherence to dentine (P < 0.001). Conditioning of LPS dentine with either nanoparticles improved SCAP viability (P < 0.01) and rescued other LPS related adverse effects on SCAPs, such as F-actin disruption, decrease in differentiation/biomineralization potential. IL-6 produced by macrophages in response to LPS-treated dentine impeded SCAP migration (P < 0.001), diminished on CSnp and Dex-CSnp conditioning groups (P < 0.01).

CONCLUSION

This study developed an LPS-dentine model and highlighted the ability of CSnp and Dex-CSnp to promote stem cell viability, migration, differentiation potential and reduce inflammation, providing an environment conducive for tissue regeneration/repair.

Outcome of endodontic treatment with chlorhexidine gluconate as main irrigant: A case series

This study evaluated the overall endodontic therapy success using 0.12% or 2% chlorhexidine gluconate as main irrigant. Seventy-two teeth diagnosed as vital, necrotic or previously treated teeth with apical periodontitis that were consecutively treated by orthograde therapy. All cases were followed clinically and radiographically for at least 1-year period. Success was established in teeth without signs or adverse clinical symptoms and complete or incomplete radiographic healing. Failure was determined in teeth with any sign or adverse clinical symptoms and a new, unchanged or enlarged radiographic periapical lesion. The data were analysed using chi-square and Fischer's exact tests. The overall success rate for teeth undergoing vital pulp was 84.6%, 76.2% as for the necrotic teeth and 84% for the retreatment cases. No significant differences were observed between groups (P > 0.05). Cases treated with CHX as main irrigant showed a high overall endodontic therapy success rate.

Effect of passive ultrasonic activation on microorganisms in primary root canal infection: a randomized clinical trial

OBJECTIVE

This clinical study sought to evaluate the effectiveness of passive ultrasonic activation (PUA) in eliminating microorganisms in primary endodontic infection (PEI) after instrumentation of root canals using microbiological culture and checkerboard DNA-DNA hybridization.

METHODOLOGY

Twenty root canals with PEI and apical periodontitis were selected. The root canals were instrumented and then randomly divided into 2 groups, according to the irrigation method: PUA and conventional needle irrigation (CNI). Microbiological samples were collected before instrumentation (S1), after instrumentation (S2) and after irrigation with 17% EDTA (S3). The samples were subjected to anaerobic culture technique and checkerboard DNA-DNA hybridization analysis.

RESULTS

A statistically significant difference was found between CNI (23.56%) and PUA (98.37%) regarding the median percentage values for culturable bacteria reduction (p<0.05). In the initial samples, the most frequently detected species was S. constellatus (50%), and after root canal treatment was E. faecalis (50%).

CONCLUSION

Both treatments significantly decreased the number of bacterial species compared with the initial sample. However, no statistical difference in the total microbial load between PUA and CNI groups was detected. The number of cultivable anaerobic bacteria reduced significantly using PUA, and the bacterial composition and number of bacterial species after using either CNI or PUA was similar.

The inhibitory effect of quaternary ammonium salt on bacteria in root canal

Persisting apical periodontitis is a primary reason for multiple intervention in root canal. Persisting bacteria in root canal is related with the persisting infection. Despite the advancement in treatment strategies the persisting infection is a major challenge for endodontist. Here we tested two newly developed quaternary ammonium methacrylates (QAMs) against endodontic bacteria and their biofilms. Their antibacterial and antibiofilm efficiency were compared with chlorhexidine (CHX) and sodium hypochlorite (NaOCl). We measured the MIC, MBC and MBIC of DMADDM and DMAHDM respectively. We also detected the ratio of live/dead bacteria and bacterial composition in the biofilms treated by DMADDM and DMAHDM. We found that DMADDM and DMAHDM could inhibit the growth of bacteria and biofilms formation. The result showed that novel QAMs were remarkably efficient than CHX against biofilms. In addition, we found that Streptococcus gordonii (S. gordonii) and Enterococcus faecalis (E. faecalis) were frequent isolates after treatment with antimicrobial compounds.

A Regenerative Approach for Root Canal Treatment of Mature Permanent Teeth: Comparative Evaluation with 18 Months Follow-up

Aim

SealBio is a novel technique which stimulates the periradicular cells to deposit a biological barrier at the root apex by inducing healing and regeneration. This clinical trial was undertaken to compare the outcome of teeth treated with the SealBio and the obturation technique.

Materials and methods

Thirty patients met the inclusion criteria and consented to participate in the study. Patients were randomly assigned to the SealBio and the obturation group. The time taken for both the techniques and periapical healing was evaluated. The patients of both the groups were evaluated at 6, 12, and 18 months follow up. The periapical index (PAI) was the primary outcome measure to check the apical bone density and healing. The secondary outcome measure was the presence/absence of signs and symptoms. The final outcome measure was the sum of the primary and secondary outcome measures.

Results and conclusion

The time taken to perform endodontic treatment with the SealBio technique was significantly lesser than that of obturation. Both groups showed equally favorable outcomes at the end of 18 months without any statistically significant differences.

Clinical significance

The results of the present study have demonstrated that SealBio technique gives similar results as that of conventional gutta-percha obturation. The shortcomings of obturation such as difficulty in obtaining a fluid-tight seal and difficulty in obturating tortuous canals can be overcome by the SealBio method. The SealBio method is cost effective, less technique sensitive, and takes lesser chair time.

How to cite this article

Jha P, Virdi MS, et al. A Regenerative Approach for Root Canal Treatment of Mature Permanent Teeth: Comparative Evaluation with 18 Months Follow-up. Int J Clin Pediatr Dent 2019;12(3):182–188.

Influence of Citric Acid on the Vitality of Stem Cells from Apical Papilla

The endodontic treatment of immature permanent teeth with necrotic pulp is a serious clinical challenge. The chemical agents, used in regenerative procedures, should be selected not only based on their bactericidal/bacteriostatic properties, but also on their ability to ensure the survival of the patient’s stem cells. The aim of this study was to evaluate the effect of citric acid on the vitality of SCAP in a model of an immature tooth root. Models of immature roots were created from 12 freshly extracted teeth. The models were gas sterilized with ethylene oxide and they were separated into three groups, based on the used combinations of irrigants: 1) 1.5% sodium hypochlorite / 17% EDTA; 2) 1.5% sodium hypochlorite / 10% citric acid; 3) saline. SCAPs in a hyaluronic acid–based scaffold were seeded into the canals and cultured for 7 days. Viable cells were quantified using a colorimetric assay. There was no statistically significant difference between the groups, irrigated with NaOCl/EDTA and NaOCl/citric acid. The results from our experiment show that 10% citric acid can be used in combination with 1.5% NaOCl in a regenerative endodontic procedure.

Novel Endodontic Disinfection Approach Using Catalytic Nanoparticles

INTRODUCTION

The aim of this study was to test a new disinfection technology using biomimetic iron oxide nanoparticles (IO-NPs) with peroxidaselike activity to enhance antibacterial activity on root canal surfaces and in dentinal tubules.

METHODS

The canal surfaces and dentinal tubules of single-rooted intact extracted teeth were infected by growing Enterococcus faecalis biofilms for 3 weeks. The samples were divided into 6 treatment groups: (1) phosphate-buffered saline (PBS) (negative control), (2) 3% hydrogen peroxide (H₂O₂) (test control), (3) IO-NPs (0.5 mg/mL) (test control), (4) IO-NPs (0.5 mg/mL) + 3% H₂O₂, (5) 3% sodium hypochlorite (positive control), and (6) 2% chlorhexidine (positive control). Environmental scanning electron microscopy coupled with energy-dispersive spectroscopy was used to confirm IO-NPs binding to the canal surface after a single treatment. Specimens were labeled with fluorescent staining for live/dead cells, and confocal laser scanning microscopy was used for the quantification of dead bacteria relative to the negative control (PBS).

RESULTS

Both biofilm formation and dentinal tubule infection were successfully recapitulated using the in vitro model. IO-NPs were capable of binding to the infected canal surfaces despite a single, short-term (5-minute) treatment. IO-NP activation of H₂O₂ killed significantly more E. faecalis present on the canal surfaces and at different depths of dentinal tubules when compared with all other experimental groups (P < .05-.0005).

CONCLUSIONS

The results reveal the potential to exploit nanocatalysts with enzymelike activity as a potent alternative approach for the treatment of endodontic infections.

An in vivo comparison of the antibacterial efficacy of photoactivated disinfection, diode laser, and 5% sodium hypochlorite in root canal disinfection

Background:

Pulpal infections are caused by varied number of organisms and are located in various sites of root canal system. Thus, the success of root canal treatment depends on complete eradication of microbiota.

Materials and Methods:

Thirty-two patients were selected and divided into four groups (photoactivated disinfection [PAD], diode laser, 5% sodium hypochlorite [NaOCl], and normal saline). The treatment was done according to groups, following manufacturer's instructions. The efficacies of groups were evaluated using microbial culturing technique. Three samples were taken for each group and were incubated separately for aerobic and anaerobic culture. Microbial counting was done for each sample in the form of colony-forming units.

Results:

It was evaluated using two-way analysis of variance and Friedman test. All the groups showed reduction in number of bacteria. However, for group A P < 0.0001 when analyzed for aerobic and anaerobic microorganisms, whereas, with Group B and C, P < 0.0001 for aerobic microorganisms.

Conclusion:

PAD, diode laser, and 5% NaOCl showed antibacterial action against aerobic and anaerobic bacteria.

Bioactivity of Photoactivated Functionalized Nanoparticles Assessed in Lipopolysaccharide-contaminated Root Canals In Vivo

INTRODUCTION

The persistence of dentin-bound lipopolysaccharides (LPS) in disinfected root canals impedes treatment outcomes of endodontic procedures. This study assessed the effects of photoactivated rose bengal-functionalized chitosan nanoparticles (CSRBnps) on LPS-contaminated root dentin in vivo using an intraosseous implantation model and neotissue formation as a marker.

METHODS

Fifty human, 3-mm-long root segments with a 1.2-mm canal lumen were divided into 5 groups (n = 10): group 1, canals not contaminated; group 2, canals contaminated with Pseudomonas aeruginosa LPS; group 3, canals contaminated and disinfected with sodium hypochlorite (NaOCl); group 4, canals contaminated and disinfected with NaOCl and calcium hydroxide; and group 5, canals contaminated and disinfected with NaOCl and CSRBnps (300 μg/mL) with photoactivation (λ = 540 nm, 40 J/cm²). Specimens were implanted into mandibles of guinea pigs, block dissected after 4 weeks, and the canal content evaluated histologically and immunohistochemically. The ingrown neotissue interface (50 μm) with dentin was characterized for fibroblasts, osteoclasts, inflammatory markers, dentin resorption, mineralization, and angiogenesis and dichotomized as type 1 (no inflammation and resorption, indicative of LPS inactivation) or type 2 (inflammation and resorption). The frequency of the observed parameters was analyzed using the Fisher exact test.

RESULTS

The outcome was categorized as type 1 in groups 1 and 5, type 2 in group 2, and mixed type 1 and 2 in groups 3 and 4. The outcomes in groups 1 and 5 (P > .05) differed significantly (P < .05) from those in groups 2, 3, and 4.

CONCLUSIONS

Disinfection of LPS-contaminated root canals with photoactivated CSRBnps in vivo supported ingrowth of neotissue without signs of inflammation or resorption, suggestive of effective inactivation of dentin-bound LPS.

Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial

AIM

This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals.

METHODOLOGY

Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UI - ultrasonic irrigation (n = 25) and Group NI - needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the Mann-Whitney U-test (P < 0.05).

RESULTS

All S1 samples were positive for bacteria, with median numbers of 1.49 × 10⁶ and 8.55 × 10⁵ bacterial cells for the UI and NI groups, respectively. This number significantly decreased in S2 samples (UI: 1.41 × 10⁴ ; NI: 3.53 × 10⁴ ; both with P < 0.001). After final irrigation protocols, there was a significant decrease in bacterial load from S2 to S3 samples in both groups (UI: 4.29 × 10³ ; NI: 1.08 × 10⁴ ; P < 0.01). Intergroup analysis revealed a significant difference between irrigation methods regarding bacterial counts in S3 samples (P < 0.05). In contrast, no significant differences were observed between groups for endotoxin levels (P > 0.05).

CONCLUSIONS

Ultrasonic activation was more effective than nonactivated irrigation for reducing the number of bacteria but not the endotoxin levels in root canals of teeth with apical periodontitis.

Effect of human, dentin, albumin and lipopolysaccharide on the antibacteerial activity of endodontic activity of endodontic irrigants

Context

Human dentin powder (HD), bovine serum albumin (BSA) and endotoxin (LPS) may affect the antimicrobial activity of irrigating solutions.

Aim

To evaluate the inhibitory effect of HD powder, BSA, and LPS on the antibacterial activity of 0.5%, 1%, 2.5%, and 5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) gel, BioPure mixture of tetracycline, citric acid, and detergent (MTAD), and QMix.

Methods

The direct contact test against Enterococcus faecalis (ATCC 29212) for 2-min, 30-min and 6-h was used. Sterile pyrogen-free water was the negative control. After experimental periods, a neutralizing agent was used. Colony-forming units were determined by 10-fold serial dilutions and culture on agar plates. Data were analyzed by Kruskal-Wallis and Dunn's test (α = 5%).

Results

In the absence of inhibitors, all irrigants eliminated E. faecalis. In contact with HD, all solutions eliminated E. faecalis within 2-min, with the exception of MTAD. In the presence of BSA, only 5% NaOCl killed E. faecalis within 2-min. LPS did not affect the antibacterial effect of any irrigant. At 30-min and at 6-h, all substances eliminated E. faecalis.

Conclusions

In the presence of albumin, irrigants needed >2-min to eliminate E. faecalis, except for 5% NaOCl. The same was observed in the presence of dentin when E. faecalis was exposed to MTAD.

Clinical efficacy of EDTA ultrasonic activation in the reduction of endotoxins and cultivable bacteria

AIM

This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis.

METHODOLOGY

Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05).

RESULTS

Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL^-1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL^-1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05).

CONCLUSIONS

Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.

Contamination Controls for Analysis of Root Canal Samples by Molecular Methods: An Overlooked and Unsolved Problem

INTRODUCTION

It has been almost 20 years since molecular methods were first described for the analysis of root canal microbial flora. Contamination control samples are essential to establish DNA decontamination before taking root canal samples, and this review assessed those studies.

METHODS

Using PubMed, a search was conducted for studies using molecular microbial analysis for the investigation of endodontic samples. Studies were grouped according to the cleaning protocol, acquisition methods, and processing of control samples taken to check for contamination.

RESULTS

Of 136 studies applying molecular analysis to root canal samples, 21 studies performed surface cleaning and checking nucleotide decontamination with contamination control samples processed by polymerase chain reaction. Only 1 study described disinfection, sampling from the access cavity, and processing by polymerase chain reaction and reported the result; that study reported that all samples contained contaminating bacterial DNA.

CONCLUSIONS

Cleaning, disinfection, and checking for contamination are basic scientific prerequisites for this type of investigation; yet, this review identifies it as an overlooked issue. On the basis of this review, we call for improved scientific practice in this field.

An analysis in vivo of intracanal bacterial load before and after chemo-mechanical preparation: A comparative analysis of two irrigants and two activation techniques

Background

The goals of this randomized double-blind trial were to assess the antimicrobial activity in vivo of Sodium hypochlorite (NaOCl) vs. chlorhexidine gluconate (CHX) used in combination either with EndoActivator® or IRRI S® files in patients with apical periodontitis.

Material and Methods

A total of 120 patients with apical periodontitis (in single or multiple root canals) were randomly assigned to the four irrigation protocols outlined below: Group A: 5.25% sodium hypochlorite (NaOCl) + EndoActivator®; Group B: 5.25% NaOCl + IRRI S® files; Group C: 2% chlorhexidine gluconate (CHX) + EndoActivator®; Group D: 2% CHX + IRRI S® files. Paper points were used to collect microbiological samples before (1A samples) and after (1B samples) irrigation. Viable colony-forming units (CFU) were quantified twice: (1) without speciation, and (2) only for Enterococcus Faecalis(EF). Statistical analysis was performed using SPSS 22.0 for Windows.

Results

No significant differences were observed between NaOCl and CHX in the reduction of CFU; in fact, reduction was < 93% for the two irrigants. Conversely, statistically significant differences were found between the two activation techniques (sonic and ultrasonic) in the reduction of Enterococcus Faecalis(EF). Thus, the effectiveness of ultrasonic activation was significantly higher (< 93%; p=0.012) as compared to sonic activation. Following the combination of the two irrigants with the two activation techniques (groups A, B, C and D), significant differences were observed between group A and B (p=0.025) in the reduction of EF populations, reaching up to 94%.

Conclusions

NaClO and CHX are effective in reducing intracanal bacterial load. Ultrasonic activation is the most effective activation technique in reducing EF populations.

Key words:Chlorhexidine gluconate, sodium hypochlorite, ultrasonic irrigation, sonic irrigation, apical periodontitis, Enterococcus faecalis.

A Comparative Evaluation of the Effectiveness of Three Different Irrigating Solution on Microorganisms in the Root Canal: An Invivo Study

INTRODUCTION

An infected root canal system either due to caries exposure or trauma cannot be eliminated by the host defense mechanisms alone or in combination with systemic antibiotic therapy. It can be treated through professional endodontic intervention using both chemical and mechanical procedures.

AIM

To suggest triple antibiotic solution containing tetracycline, ornidazole and ciprofloxacin as a new endodontic irrigant that may possess superior antibacterial activity in comparison with chlorhexidine solution.

MATERIALS AND METHODS

This study was carried out on 60 teeth from 40 children with anterior tooth fracture, asymptomatic, non-vital and necrotic in nature. Patients were randomly divided into three groups of 20 teeth each depending upon the type of irrigant. After access opening microbial samples were obtained: a) Pre- irrigation i.e. sample after pulp extirpation and before irrigation, b) Post-irrigation i.e. sample after irrigation, stored in sterile containers and immediately transferred to microbiological laboratory. After incubation of samples aerobically at 37(0)C for 24 hours, the samples were streaked on blood agar culture media and incubated for 48 hours. After 48 hours, the colony forming units were counted using a colony counter. Statistical analysis was carried out using Kruskal-Wallis test, Wilcoxson signed rank test and Mann-Whitney test.

RESULTS

On intra group comparison, highly significant differences in the colony forming units were found between pre-irrigation and post-irrigation sample for all the three groups. On inter group comparison, statistical difference was found between saline and chlorhexidine (p ≤ 0.001), saline and triple antibiotic paste (p< 0.001). The greatest percentage decrease was obtained in samples treated with Chlorhexidine solution (Group 2) i.e.73.91. The triple antibiotic irrigating solution group showed percentage decrease of 66.22 followed by Group 1 (Saline) 15.04. The difference found amongst the groups was statistically insignificant.

CONCLUSION

It was concluded that triple antibiotic irrigating solution can be used as an irrigating solution. The antibacterial action of triple antibiotic irrigating solution is comparable with chlorhexidine. Although saline may not be effective in the antimicrobial action but its flushing action may be able to decrease some microbial load.

Influence of Concentration and Agitation of Sodium Hypochlorite and Peracetic Acid Solutions on Tissue Dissolution

AIM AND OBJECTIVE

To evaluated the tissue dissolution of sodium hypochlorite (NaOCl) and peracetic acid (PA) solutions at different concentrations, with or without ultrasonic agitation.

MATERIALS AND METHODS

The following solutions were analyzed: 2.5% NaOCl, 0.5, 1 and 2% PA, 1% PA associated with 6.5% hydrogen peroxide (HP) and saline. Fragments of bovine pulp tissue with 25 ± 2g mg were immersed into test tubes containing 4 mL of the solutions for 10 minutes. In the groups with agitation, pulp tissues were submitted to 2 cycles of 1 minute of ultrasonic agitation. The specimens were weighed after the removal from the solutions. The percentage of mass loss was calculated according to the difference of mass before and after exposure to solutions. Data were submitted to ANOVA and Tukey tests (p < 0.05).

RESULTS

A total of 2.5% NaOCl with or without agitation showed the higher tissue dissolution (between 64.5 and 67% of mass reduction) (p < 0.005). By comparing the PA solutions, the concentrations of 1 and 2% with or without agitation and the concentration of 0.5% with agitation showed similar dissolution activity (between 35.4 and 44% of mass reduction). The use of the ultrasonic agitation promoted an increase of the dissolution ability only for 0.5% PA.

CONCLUSION

Peracetic acid solution has pulp tissue dissolution. However, this ability is lower than 2.5% NaOCl solution.

CLINICAL SIGNIFICANCE

The sodium hypochlorite solution shows higher ability to dissolve tissue than PA.

Microbiomes of Endodontic-Periodontal Lesions before and after Chemomechanical Preparation

INTRODUCTION

This study was conducted to evaluate the microbiomes of endodontic-periodontal lesions before and after chemomechanical preparation (CMP).

METHODS

Clinical samples were taken from 15 root canals (RCs) with necrotic pulp tissues and from their associated periodontal pockets (PPs) (n = 15) of teeth with endodontic-periodontal lesions before and after CMP. The Human Oral Microbe Identification using Next Generation Sequencing (NGS) protocol and viable culture were used to analyze samples from RCs and PPs. The Mann-Whitney U test and Benjamini-Hochberg corrections were performed to correlate the clinical and radiographic findings with microbial findings (P < .05).

RESULTS

Bacteria were detected in 100% of the samples in both sites (15/15) using NGS. Firmicutes was the most predominant phylum in both sites using both methods. The most frequently detected species in the RCs before and after CMP using NGS were Enterococcus faecalis, Parvimonas micra, Mogibacterium timidum, Filifactor alocis, and Fretibacterium fastidiosum. The species most frequently detected in the PPs before and after CMP using NGS were P. micra, E. faecalis, Streptococcus constellatus, Eubacterium brachy, Tannerella forsythia, and F. alocis. Associations were found between periapical lesions ≤ 2 mm and Desulfobulbus sp oral taxon 041 and with periodontal pockets ≥ 6 mm and Dialister invisius and Peptostreptococcus stomatis (all P < .05, found in the RCs before CMP).

CONCLUSIONS

It is concluded that the microbial community present in combined endodontic-periodontal lesions is complex and more diverse than previously reported. It is important to note that bacteria do survive in some root canals after CMP. Finally, the similarity between the microbiota of both sites, before and after CMP, suggests there may be a pathway of infection between the pulp and periodontium.

Infection Control in Retreatment Cases: In Vivo Antibacterial Effects of 2 Instrumentation Systems

INTRODUCTION

This in vivo study compared the antibacterial effects of 2 instrumentation systems in root canal-treated teeth with apical periodontitis.

METHODS

Forty-eight teeth with a single root and a single canal showing post-treatment apical periodontitis were selected for this study. For retreatment, teeth were randomly divided into 2 groups according to the instrumentation system used: Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel) and Twisted File Adaptive (TFA; SybronEndo, Orange, CA). In both groups, 2.5% sodium hypochlorite was the irrigant. Bacteriological samples were taken before (S1) and after chemomechanical preparation (S2). In the TFA group, passive ultrasonic irrigation (PUI) was performed after instrumentation, and samples were also taken after this supplementary step (S2b). DNA was extracted from the clinical samples and subjected to quantitative real-time polymerase chain reaction to evaluate the levels of total bacteria, streptococci, and Enterococcus faecalis. Statistical analyses from quantitative real-time polymerase chain reaction data were performed within groups using the Wilcoxon matched pairs test and between groups using the Mann-Whitney U test and the Fisher exact test with the significance level set at P < .05.

RESULTS

Bacteria were detected in S1 samples from 43 teeth, which were then included in the antibacterial experiment. Both SAF and TFA instrumentation protocols showed a highly significant intracanal bacterial reduction (P < .001). Intergroup quantitative comparisons disclosed no significant differences between TFA with or without PUI and SAF (P > .05). PUI did not result in significant improvement in disinfection (P > .05).

CONCLUSIONS

Both instrumentation systems/treatment protocols were highly effective in significantly reducing the intracanal bacterial counts. No significant difference was observed between the 2 systems in disinfecting the canals of teeth with post-treatment apical periodontitis.