Intratubular decontamination ability and physicochemical properties of calcium hydroxide pastes

Biochemical properties of novel Carbon nanodot-stabilized silver nanoparticles enriched calcium hydroxide endodontic sealer

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15-20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100-120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects.

Comparative Analysis of AH Plus Bond Strength to Root Canal Dentin and Adhesive Interface Quality after Calcium Hydroxide Removal using Different Irrigation Protocols

INTRODUCTION

To evaluate the push-out bond strength (POBS) of AH Plus sealer to root dentin and the adhesive interface quality after calcium hydroxide (Ca(OH)2) intracanal dressing removal with different final irrigation protocols.

METHOD

After root canal instrumentation and irrigation, 40 root canals were filled with Ca(OH)2 and sealed. After 14 days, the specimens were randomly distributed according to the irrigation protocols for Ca(OH)2 removal (n = 10): GH2O (control) - distilled water; GNaOCl - 1% NaOCl; GEDTA - 17% EDTA; GEDTA + NaOCl - 17% EDTA + 1% NaOCl. The root canals were filled with AH Plus sealer and gutta-percha. After 7 days, the roots were sectioned into dentin slices and submitted to POBS test and analysis of the adhesive interface under scanning electron microscope. The POBS data were statistically evaluated (analysis of variance and Tukey test). The Kruskal-Wallis and Mann-Whitney tests were used to analyze the adhesive interface (α = 0.05).

RESULTS

GH2O, GNaOCl, and GEDTA + NaOCl had similar POBS values, with higher values on the apical third, in comparison with other thirds (P < .05). A homogeneous and free-of-gaps adhesive interface was observed for GH2O, GNaOCl, and GEDTA + NaOCl, with difference between GH2O and GEDTA (P < .05). GH2O and GEDTA + NaOCl presented higher sealer tags formation (P < .05).

CONCLUSION

The final rinse with EDTA for Ca(OH)2 dressing removal had a negative effect on the POBS of the filling material to root dentin. The use of EDTA followed by NaOCl had results similar to the distilled water, providing uniform and free-of-gaps adhesive interface, and a higher number of sealer tags.

Effect of experimental dentin etchants on dentin bond strength, metalloproteinase inhibition, and antibiofilm activity

OBJECTIVE

this study evaluated dentin microtensile bond strength (µTBS) and failure modes (at 24 h and one year), bonding interface regarding hybridization, surface morphology regarding demineralization, in situ metalloproteinase (MMP) activity, and antibacterial effect of three dentin etchants compared to 35% phosphoric acid (PA).

MATERIALS AND METHODS

The Adper Single Bond 2 adhesive (3 M Oral Care) was applied on moist dentin etched with PA (control) or on air-dried dentin etched with 3% aluminum nitrate + 2% oxalic acid (AN), 6.8% ferric oxalate + 10% citric acid (FO), or 10% citric acid (CA). The µTBS test used 40 human teeth (n = 10). Failure modes and surface morphology were analyzed by scanning electron microscopy (n = 3), while bonding interface morphology and MMP activity were evaluated by laser scanning confocal microscopy (n = 3). Antibacterial activity was evaluated against S. Mutans biofilm by means of viable cells count (CFU/mL).

RESULTS

PA presented the highest bond strengths regardless of aging time. PA, AN, and CA showed stable bond strengths after one year of storage. Adhesive and mixed failures were predominant in all groups. Thin hybrid layers with short resin tags were observed for the experimental etchants. The AN-based etchant was able to inhibit MMP activity. All tested etchants presented antibacterial activity against S. Mutans biofilm.

SIGNIFICANCE

This study suggests different dentin etchants capable of inhibiting MMP activity while also acting as cavity disinfectants.

Expert consensus on irrigation and intracanal medication in root canal therapy

Chemical cleaning and disinfection are crucial steps for eliminating infection in root canal treatment. However, irrigant selection or irrigation procedures are far from clear. The vapor lock effect in the apical region has yet to be solved, impeding irrigation efficacy and resulting in residual infections and compromised treatment outcomes. Additionally, ambiguous clinical indications for root canal medication and non-standardized dressing protocols must be clarified. Inappropriate intracanal medication may present side effects and jeopardize the therapeutic outcomes. Indeed, clinicians have been aware of these concerns for years. Based on the current evidence of studies, this article reviews the properties of various irrigants and intracanal medicaments and elucidates their effectiveness and interactions. The evolution of different kinetic irrigation methods, their effects, limitations, the paradigm shift, current indications, and effective operational procedures regarding intracanal medication are also discussed. This expert consensus aims to establish the clinical operation guidelines for root canal irrigation and a position statement on intracanal medication, thus facilitating a better understanding of infection control, standardizing clinical practice, and ultimately improving the success of endodontic therapy.

Effects of natural antimicrobial compounds propolis and copaiba on periodontal ligament fibroblasts, molecular docking, and in vivo study in Galleria mellonella

Root canal treatment addresses infectious processes that require control. Occasionally, the radicular pulp is vital and inflamed, presenting a superficial infection. To preserve pulpal remnants, conservative procedures have gained favor, employing anti-inflammatory medications. This study investigated the effects of propolis (PRO), and copaiba oil-resin (COR) associated with hydrocortisone (H) and compared their impact to that of Otosporin® concerning cytotoxic and genotoxic activity, cytokine detection, and toxicity in the Galleria mellonella model. Human periodontal ligament fibroblasts (PDLFs) were exposed to drug concentrations and evaluated by the MTT assay. Associations were tested from concentrations that did not compromise cell density. Genotoxicity was evaluated through micronucleus counting, while cytokines IL-6 and TGF-β1 were detected in the cell supernatant using ELISA. Molecular docking simulations were conducted, considering the major compounds identified in PRO, COR, and H. Increasing concentrations of PRO and COR were assessed for acute toxicity in Galleria mellonella model. Cellular assays were analyzed using one-way ANOVA followed by Tukey tests, while larval survivals were evaluated using the Log-rank (Mantel-Cox) test (α = 0.05). PRO and COR promoted PDLFs proliferation, even in conjunction with H. No changes in cell metabolism were observed concerning cytokine levels. The tested materials induce the release of AT1R, proliferating the PDFLs through interactions. PRO and COR had low toxicity in larvae, suggesting safety at tested levels. These findings endorse the potential of PRO and COR in endodontics and present promising applications across medical domains, such as preventive strategies in inflammation, shedding light on their potential development into commercially available drugs.

Antimicrobial effect of grape seed extract as a potential intracanal medicament combined with Nd:YAG laser

This study evaluated the antimicrobial efficacy of grape seed extract medicament combined with Nd:YAG laser, against Enterococcus faecalis, Staphylococcus aureus and Candida albicans biofilms. Root canals infected with 4-week-old biofilms were divided into five groups (n = 11): calcium hydroxide, 6.5% GSE, Nd:YAG laser (1064 nm, 1.5 w, 15 Hz and 100 mj) and 6.5% GSE followed by Nd:YAG laser and normal saline (control). Dentin chips were collected using Gates-Glidden and cultured to obtain colony-forming units. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U test. GSE showed higher antibacterial activity against all species investigated compared to Ca(OH)2 . However, the lowest microbial count was obtained using a combination of GSE and Nd:YAG laser (p < 0.001). No significant difference in the susceptibility of tested pathogens to each of the protocols was observed (p > 0.05). Application of Nd:YAG laser following GSE medicament is efficient against endodontic biofilms; also, GSE can be considered as an alternative to Ca(OH)2 dressing.

Novel technologies to improve the treatment of endodontic microbial infections: Inputs from a drug delivery perspective

Endodontic microbial infections are still a challenge for an effective treatment for being biofilm-mediated and very refractory to conventional therapies. Biomechanical preparation and chemical irrigants cannot fully eradicate biofilms due to the anatomic structure of the root canal system. Instruments employed in biomechanical preparation and irrigants solution cannot reach the narrow and deepest portion of root canals, especially the apical thirds. In addition, aside from the dentin surface, biofilms can also infiltrate dentine tubules and periapical tissues, compromising treatment success. Therefore, different technologies have been investigated to achieve a more effective outcome in the control of endodontic infections. However, these technologies continue to face great difficulties in reaching the apical region and eradicating biofilms to avoid the recurrence of infection. Here, we present an overview of the fundamentals of endodontics infections and review technologies currently available for root canal treatment. We discuss them from a drug delivery perspective, highlighting each technology's strength to envision the best use of these technologies.

Evaluation of pH and calcium ions release of two tricalcium silicate-based sealers through roots of primary teeth

Background

This study aimed to evaluate the pH and calcium ions (Ca2+) release from two tricalcium silicate-based sealers (Sealer Plus BC and Bio-C Pulpecto) through roots of primary teeth.

Methods

Forty root canals of primary incisors were prepared and distributed into four groups according to the filling material: GPlusBC (Sealer Plus BC); GBioC (Bio-C Pulpecto); GUltra (Ultracal); and GC (no filled). pH measurement was performed with a digital pH meter, and the Ca2+ release was measured in an atomic absorption spectrophotometer at baseline, 24 h and 1, 2, 3, and 4 weeks later. The data were analyzed using two-way ANOVA and Tukey's post hoc tests.

Results

The results did not reveal significant differences between the groups in terms of pH in 24 h, 1-, and 2-weeks' periods. After 4 weeks, there was a significant difference, with the highest mean pH values in GUltra, followed, respectively, by GPlusBC and GBioC. Regarding the Ca2+ release, the GUltra showed greatest mean values at all evaluated times, and the other groups showed no difference between them.

Conclusion

Both sealers were able to promote the elevation of the pH and Ca2+ release through roots of primary teeth, which brings favorable properties for their use as a filling material.

The Vehicles of Calcium Hydroxide Pastes Interfere with Antimicrobial Effect, Biofilm Polysaccharidic Matrix, and Pastes' Physicochemical Properties

The objective of the present study was to investigate the pH, volumetric alteration, antimicrobial action, and effect on biofilm matrix polysaccharides of calcium hydroxide (CH) pastes with different vehicles available in endodontics: CH + propylene glycol (CHP), UltraCal XS^®, Metapaste^®, and Metapex^®. The pH was analyzed at different time intervals using a pH meter. For volumetric alteration, a microtomographic assay was performed before and after immersion in water. Enterococcus faecalis was chosen for microbiological tests. The bacterial viability and extracellular matrix were quantified with direct contact evaluation (dentin blocks) and at the intratubular level (dentin cylinders) using LIVE/DEAD BacLight and Calcofluor White dyes via confocal laser scanning microscopy (CLSM). Kruskal-Wallis and Dunn's tests were used to analyze pH and direct contact assays, while one-way ANOVA and Tukey tests were used to analyze volumetric alteration and intratubular decontamination (α = 0.05). Higher pH values were obtained during the initial days. Volumetric alterations were similar in all groups. Lower bacterial viability was obtained for dentin blocks and cylinders when CH pastes were used. UltraCal XS and Metapex had lower values for the extracellular matrix. The pH of all CH pastes decreased with time and did not promote medium alkalization for up to 30 days. CH paste can reduce bacterial viability through direct contact and at an intratubular level; however, UltraCal XS and Metapex are involved with lower volumes of extracellular matrices.

Biocompatibility and Antibacterial Action of Salvadora persica Extract as Intracanal Medication (In Vitro and Ex Vivo Experiment)

This study aimed to test the biocompatibility and antibacterial properties of Salvadora persica (S. persica) extract, a natural product, as an intracanal medication in comparison with calcium hydroxide (Metapaste, META BIOMED, Cheongju, Korea). The pH values of both materials were tested. The biocompatibility of S. persica extract and Metapaste was determined using light microscopy and MTT assays. The antibacterial action was tested using the zone of bacterial inhibition on four common bacterial species. In addition, intracanal medication was administered using 68 extracted single-rooted teeth contaminated with Enterococcus faecalis (E. faecalis), and the percentage reduction in colony count (% RCC) at 1, 3, and 7 days was measured. The extension of activity for both materials was assessed using histological sections and scanning electron microscopy. S. persica was found to be acidic in nature. Both materials showed significantly lower cell viability than the positive control cells on days 1 and 3 but not on day 7. S. persica showed better antibacterial effects against E. faecalis and S. mutans. S. persica extract showed 97.6%, 98.9%, and 99.3% RCC values at 1, 3, and 7 days, respectively, which are comparable to those of Metapaste. S. persica herbal extract is a promising material that can be utilized as an intracanal medication, but its use requires further research.

Impact of irrigation protocols with some chelators and mechanical agitation on intratubular decontamination

This study evaluated main canal and intratubular decontamination using different irrigation solutions followed by adjunctive agitation steps for infected root canals. Sixty-eight lower incisors were contaminated with Enterococcus faecalis and allocated to groups according to canal treatment (n = 10): G1, NaOCl followed by ethylenediaminetetraacetic acid (EDTA); G2, a mixture of NaOCl with hydroxyethylidene bisphosphonate (HEBP); and G3, NaOCl followed by EDTA-T (EDTA with sodium lauryl ether sulfate). All three groups of teeth were agitated with passive ultrasonic irrigation (PUI) using saline solution, whereby G4, G5, and G6 were prepared as above, and agitation was performed using an XP-Endo Finisher instrument. Microbiological samples were collected from the root canals with paper points at three times: before and after chemomechanical preparation and after agitation. The colony-forming units (CFU)/mL count was determined, and bacterial intratubular viability was analyzed via confocal laser scanning microscopy using Live/Dead staining. Statistical analysis was performed using a Kruskal-Wallis test followed by Dunn tests. A Friedman test was applied for colony-counting data (α = 0.05). CFU/mL counting indicated equally effective decontamination in the experimental groups (p > 0.05). According to microscopy images, the use of irrigation solutions followed by agitation with the XP-Endo Finisher yielded better results. Moreover, NaOCl+EDTA-T followed by XP-Endo Finisher resulted in significantly lower viability than in the PUI-activated groups (p < 0.05). The cervical and medium thirds of the specimens presented similar results. Overall, NaOCl+EDTA-T exhibited the best intratubular antibacterial activity, mainly for canals that were subsequently agitated using XP-Endo Finisher.

Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability

OBJECTIVES

The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC).

MATERIALS AND METHODS

Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM.

RESULTS

The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste.

CONCLUSIONS

All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results.

CLINICAL RELEVANCE

Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Biological and antimicrobial properties of the association Ambroxol and a water-soluble viscous liquid as a vehicle for a tricalcium silicate-based sealer

This study aimed to investigate the antimicrobial and biological properties of Ambroxol associated with glycerin (GLI), propylene glycol (PG), and polyethylene glycol (PEG) as a possible vehicle for an experimental tricalcium silicate sealer, with the intention of developing a new biomaterial. Mouse undifferentiated dental pulp cells (OD-21) were cultured, and the effects of different association on cell proliferation and inflammatory cytokine production were investigated. Antimicrobial adhesion of Enterococcus faecalis to setting sealers at 2 h was evaluated. Polyethylene tubes containing experimental sealers and empty tubes were implanted into dorsal connective tissues of 12 male 3- to 4-months-old Wistar rats (250-280 g). After 7 and 30 days, the tubes were removed and processed for histological and immunohistochemical analyses. ANOVA followed by Bonferroni correction and ANOVA followed by Tukey test was used for parametric data and Kruskal-Wallis followed by Dunn for nonparametric (p < 0.05). Cell proliferation was dose-dependent, since all association were cytotoxic at higher concentrations; however, Ambroxol-PEG showed significantly higher cytotoxicity than other association (p < 0.05). In addition, irrespective of the association, no cytokine production was observed in vitro. Ambroxol-GLI reduced bacterial viability, whereas Ambroxol-PEG increased (p < 0.05). Histological examination showed no significant difference in the inflammatory response (p > 0.05) and mineralization ability in all association. Additionally, IL-1β and TNF-α were upregulated on Ambroxol-PEG in relation to Control at 07 days (p < 0.05). Ambroxol-GLI was the best vehicle for experimental tricalcium silicate sealer, as it promoted an increase in antimicrobial activity without altering the inflammatory response or mineralization ability.

How Adding Chlorhexidine or Metallic Nanoparticles Affects the Antimicrobial Performance of Calcium Hydroxide Paste as an Intracanal Medication: An In Vitro Study

The aim of our study was to explore the potential value of metallic (Ag, Cu, and Zn) salts, polymer/metallic nanoparticles, and chlorhexidine (CHX) for improving the antimicrobial activity of calcium hydroxide (CH) against E. faecalis and C. albicans, associated with persistent endodontic infections. A first screening was performed by determining minimum inhibitory/bactericidal concentrations (MIC/MBC). Antimicrobial activity of the CH paste mixed with metallic salts, chitosan or cyclodextrin polymer metallic nanoparticles was compared to the antimicrobial activity of CH paste alone and CH + CHX using a time-kill kinetics assay. The effect of the antimicrobials on the rheological and the key mechanical properties were also examined. Copper and zinc were discarded because of their MIC/MBC values and silver because of its kill time curve profile. Except for a slower setting time after 24 h and a higher weight loss after 1 week of incubation, the mechanical behavior of the CH paste was unaffected by the addition of CHX. Polymeric/metallic nanoparticles failed to potentiate the antimicrobial effect of CH. By contrast, CHX increased this effect and thus could help eradicate E. faecalis associated with persistent root canal infections without altering the desired key physical properties of the CH paste.

Effect of the several epoxy resin-based sealer compositions on adhesion interface in radicular dentin after calcium hydroxide intracanal medication removal

Background

This study evaluated the effects of several epoxy resin-based sealer compositions (AHP, AH Plus; ADS, Adseal; SPL, Sealer Plus) on bond strength and intratubular dentin penetration of the endodontic obturation, in root canal previously treated with calcium hydroxide intracanal medication (CH) and removed by continuous ultrasonic irrigation (CUI).

Material and Methods

Forty-five maxillary canines were prepared up to F5 (ProTaper system), filled with CH, coronally sealed, and stored at 37ºC. After 1 week, CH was removed using 2.5% sodium hypochlorite energized by CUI. The specimens were randomly distributed in three groups (n=15) and root canal obturated, according to epoxy-based resin sealer composition (AHP, ADS or SPL). The roots were transversally sectioned in cervical, middle, and apical thirds. In each radicular third, push out bond strength using universal machine and intratubular dentin using confocal laser scanning microscopy (CLSM) and Image J Program were evaluated. Bond strength and intratubular dentin penetration were statistically evaluated by ANOVA one-way and Tukey tests and Kruskal Wallis test, respectively (α = 0.05).

Results

In middle and apical thirds, AHP showed higher bond strength values (p<0.05), and ADS and SPL were similar each other (p>0.05). All epoxy resin-based sealers presented similar intratubular dentin penetration, independently of the radicular thirds (p>0.05). Cohesive and mixed failures were predominant in the cervical thirds. In the middle and apical thirds, AHP showed more cohesive type failures, while ADS and SPL showed more adhesive-type failures.

Conclusions

AHP has the highest bond strength in middle and apical radicular thirds, after calcium hydroxide intracanal medication removal using continuous ultrasonic irrigation, although intratubular dentin infiltration being similar among epoxy resin-based sealer with several chemical composition. Key words:Continuous ultrasonic irrigation, endodontic sealers, epoxy resin-based sealers, root canal obturation.

Antibacterial Efficacy of Triple Antibiotic Medication With Macrogol (3Mix-MP), Traditional Triple Antibiotic Paste, Calcium Hydroxide, and Ethanol Extract of Propolis: An Intratubular Dentin Ex Vivo Confocal Laser Scanning Microscopic Study

INTRODUCTION

This study aimed to assess the effectiveness of antibacterial activity of medications used in regenerative endodontic treatment.

METHODS

Sixty-seven dentin cylinders of single-rooted teeth were contaminated with a culture of Enterococcus faecalis (ATCC 29212; American Type Culture Collection, Manassas, VA) for 5 days. Samples were divided into 1 control group and the following experimental groups according to the medication applied: traditional triple antibiotic paste (TAP), clindamycin-modified TAP (mTAP), triple antibiotic medication with macrogol (3Mix-MP), clindamycin-modified 3Mix-MP (m3Mix-MP), calcium hydroxide (CH), and ethanol extract of propolis (EEP). After 14 days, the medications were removed, and the samples were submitted to confocal laser scanning microscopic analysis to quantify the percentage of viable bacteria. The distribution of data was confirmed by the Shapiro-Wilk test. The Kruskal-Wallis and Dunn tests were used for intergroup comparisons, and the Wilcoxon test was used for comparison between superficial and deep antibacterial efficacy for the same medication. The level of significance was set at P < .05.

RESULTS

3Mix-MP and m3Mix-MP presented significantly higher antibacterial efficacy compared with the other tested medications (P < .05), except for mTAP. mTAP was more effective than TAP (P < .05). The antibacterial efficacy of EEP and CH did not differ significantly from TAP and mTAP (P > .05). All medications showed effective antibacterial action compared with the control group (P < .05).

CONCLUSIONS

3Mix-MP and m3Mix-MP, which present extremely high concentrations of antibiotics (1500 mg/mL), were not more effective than mTAP at the concentration recommended by the American Association of Endodontists (5 mg/mL). Moreover, CH and EEP were as effective as TAP and mTAP.

Postoperative pain in endodontic retreatment of one visit versus multiple visits: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The aim of this systematic review and meta-analysis (SRM) was to assess the postoperative pain (PP) after non-surgical endodontic retreatment (NSER) in a one visit compared to multiple visits. The PICO question used was "Does NSER in patients with unsatisfactory endodontic treatment in a one-visit visit have a similar PP to that of NSER in multiple visits?"

MATERIALS AND METHODS

This systematic review followed PRISMA and was registered in PROSPERO (CRD42019136700). Searches were performed in the PubMed/MEDLINE, Scopus, and the Cochrane Library databases for articles published until September 2020. The eligible criteria were randomized clinical trials (RCTs). The meta-analysis was based on the Mantel-Haenszel. The PP after the retreatment was analyzed using a dichotomous outcome, measured according to risk ratio (RR) when p < 0.05. The Cochrane scale was used to assess risk of bias, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the quality of evidence.

RESULTS

Four studies were included. In general analysis without considering intensity, one-visit NSER presented lower PP than the multiple visits only for 1 and 30 days [(RR = 0.67; CI: 0.48 to 0.93; p = 0.02), and (RR = 0.09; CI: 0.01 to 0.66; p = 0.02)], respectively. Regarding sub-analysis considering the intensity, one visit present lower mild PP when compared with multiple visits [(RR = 0.54; CI: 0.30, 0.96; p = 0.04); (RR = 0.33; CI: 0.12, 0.88; p = 0.03); and (RR = 0.12; CI: 0.02, 0.86; p = 0.03)], respectively. However, sub-analysis for moderate and severe PP showed no significant difference, independently of period evaluated (p > 0.05). Regarding the risk of bias analysis, a low risk was observed for most domains, except allocation that was considered unclear, while the certainty of evidence for each analysis was considered low.

CONCLUSION

Within the limitations of study, the one and multiple visit can be considered adequate, because both present a similar occurrence of PP, except for mild pain. However, due to the low number of studies, further well conducted and standardized RCTs are needed to reassess these results.

CLINICAL RELEVANCE

Both therapies of endodontic retreatment can be considered in clinical practice. Therefore, the endodontist must consider the patient's individual characteristics and experience to consider the best treatment approach.

A New Calcium Silicate-Based Root Canal Dressing: Physical and Chemical Properties, Cytotoxicity and Dentinal Tubule Penetration

The aims of this study were to evaluate the physical and chemical properties, cytotoxicity and dentinal tubule penetration of a new calcium silicate-based root canal dressing. For pH and calcium ion release evaluation (1, 24, 72 and 168 h) were used a pH meter and colorimetric spectrophotometer, respectively. Radiopacity evaluation followed the ISO 6876:2012. Cytotoxicity was evaluated by the percentage of cell viability using MTT assay. Illustrative images of dentinal tubule penetration were obtained using confocal laser scanning microscopy (CLSM). Data from pH and calcium ion release were statistically analyzed by two-way analysis of variance and Tukey test. Radiopacity was analyzed using the Student t-test. The statistical tests for cytotoxicity results were the one-way analysis of variance and Tukey test. Both materials showed alkaline pH in all experimental times. The pH values for calcium hydroxide paste were higher than bioceramic paste at 1, 24, and 72 h (p<0.05). The calcium ion release of bioceramic was lower than the calcium hydroxide paste only at 24 h (p<0.05). The bioceramic was more radiopaque than the calcium hydroxide paste (p<0.05). Bioceramic paste presented a dose and time-dependent cytotoxic effect after MTT assay. CLSM images showed absence of tubule penetration for both pastes. The new calcium silicate-based canal dressing presented alkaline pH, high calcium release, and acceptable radiopacity. Bio C Temp showed a dose and time-dependent cytotoxic and absence of dentinal tubule penetration.

Effectiveness of chitosan-propolis nanoparticle against Enterococcus faecalis biofilms in the root canal

Background

The successful outcome of endodontic treatment depends on controlling the intra-radicular microbial biofilm by effective instrumentation and disinfection using various irrigants and intracanal medicaments. Instrumentation alone cannot effectively debride the root canals specially due to the complex morphology of the root canal system. A number of antibiotics and surfactants are being widely used in the treatment of biofilms however, the current trend is towards identification of natural products in disinfection. The aim of the study was to determine the antibacterial effect of chitosan-propolis nanoparticle (CPN) as an intracanal medicament against Enterococcus faecalis biofilm in root canal.

Methods

240 extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into eight groups (n = 30) according to the intracanal medicament placed: group I: saline, group II: chitosan, group III: propolis100 µg/ml (P100), group IV: propolis 250 µg/ml (P250), group V: chitosan-propolis nanoparticle 100 µg/ml (CPN100), group VI: chitosan-propolis nanoparticle 250 µg/ml (CPN250), group VII: calcium hydroxide(CH) and group VIII: 2% chlorhexidine (CHX) gel. Dentine shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of day one, three and seven. The non-parametric Kruskal Wallis and Mann–Whitney tests were used to compare the differences in reduction of CFUs between all groups and probability values of p < 0.05 were set as the reference for statistically significant results. The scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to CPNs. The effectiveness of CPNs were also evaluated against E. faecalis isolated obtained from patients having failed root canal treatment.

Results

The treatments of chitosan, P100, P250, CPN100, CPN250, CH and 2% CHX reduced the CFUs significantly compared to saline (p < .05). On day one and three, at 200 and 400-μm, CPN250 showed significant reduction of CFUs compared to all other groups (p < .05), while CPN100 was significantly better than other groups (p < .05) except CPN250 and 2% CHX. On day seven, at 200-μm CPN250 showed significant reduction of CFUs compared to all other groups (p < .05) except CPN100 and CHX, while at 400 μm CPN250 showed similar effectiveness as CPN100, CH and 2% CHX. SEM images showed root canal dentin treated with CPN250 had less coverage with E. faecalis bacteria similarly, CLSM images also showed higher percentage of dead E. faecalis bacteria with CPN250 than to CPN100.

Conclusion

CPN250 was the most effective in reducing E. faecalis colonies on day one, three at both depths and at day seven CPN250 was equally effective as CPN100 and 2% CHX.

Can kinematics, file diameter, and PUI influence the intracanal decontamination and apical bacterial extrusion?

The present study investigated the intracanal decontamination and apical extrusion of bacteria and debris from root canals instrumented with rotary and reciprocating systems (ProDesign Logic or ProDesign R), with different file diameters and using conventional syringe irrigation (CSI) or passive ultrasonic irrigation (PUI). Eighty extracted mandibular premolars were contaminated with Enterococcus faecalis and randomly assigned to eight experimental groups according to the root canal instrumentation and irrigation technique employed (n = 10): G1: Prodesign Logic 25.06; G2: Prodesign R 25.06; G3 and G4 were instrumented with the same single-file systems, respectively, using 35.05 diameters and CSI. G5, G6, G7, and G8 were instrumented like the previous groups, but with PUI. Apically extruded debris during instrumentation was collected into pre-weighed microtubes. The weight of the empty microtube was subtracted from the final weight to establish the amount of extruded debris. Bacteria from root canals and extruded debris were collected for a microbiological evaluation of colony forming units (CFU/mL). For statistical analyses, the Mann-Whitney and Kruskal-Wallis followed by the Dunn's tests were used (α = 0.05). All instruments caused extrusion of debris. For irrigation techniques, PUI promoted greater debris and bacterial extrusion (p < 0.05). The CFU/mL count indicated that the instrumentation of the experimental groups were equally effective in the decontamination of the root canal (p > 0.05). The systems tested (regarding file diameter and kinematics) were associated with similar amounts of apically extruded debris and root canal decontamination. PUI was associated with greater debris and bacterial extrusion.

Analysis of survival and factors associated with failure of primary tooth pulpectomies performed under general anaesthesia in children from South China

BACKGROUND

Pulpectomy is a technique recommended for treatment of irreversible pulp inflammation or necrosis. Treatment-related variables and patient factors may affect the prognosis of pulpectomy.

AIM

To investigate the survival and related predictors associated with failure of pulpectomies performed under general anaesthesia for early childhood caries.

DESIGN

Dental records of 124 patients, who underwent pulpectomy as part of comprehensive dental treatment under general anaesthesia, were reviewed and assessed. Relapse of pulpitis and periodontal periodontitis were evaluated by clinical examination and periapical film assessment at each follow-up appointment after original treatment.

RESULTS

A total of 389 teeth of 124 children were evaluated. By the end of the fourth year, 45% of teeth with pulpitis and 46% of teeth with periapical periodontitis were estimated to relapse; the median (interquartile range) number of years to relapse was 3.5 (3.4-3.8) and 3.0 (1.8-3.0) years, respectively. The follow-up frequency, number of teeth extracted, plaque index, tooth position, type of restoration, pulp status, and quality of root canal filling were observed to have independent effects on relapse.

CONCLUSION

Recurrence came earlier in teeth diagnosed with periapical periodontitis than those with pulpitis. Both treatment-related variables and patient factors could affect the prognosis of pulpectomy.

Phages in a thermoreversible sustained-release formulation targeting E. faecalis in vitro and in vivo

Introduction

Enterococcus faecalis is a key pathogen recovered from root canals when conventional treatment fails. Phage therapy has generated new interest in combating pathogens. A sustained-release formulation using specific phages against E. faecalis may offer an alternative approach.

Objectives

To evaluate the efficacy of anti-E. faecalis phages formulated in a thermo- sustained-release system against E. faecalis in vitro and in vivo.

Methods

EFDG1 and EFLK1 phages were formulated with poloxamer P407. Gelation time, phage survival, activity and toxicity were evaluated. Lytic activity was evaluated in vitro against E. faecalis at various growth phases, including anti-biofilm activity. Methods included viable bacterial count (CFU/mL), biofilm biomass determination and electron microscopy (live/dead staining). Further evaluation included infected incisors in an in vivo rat model. Anti-E. faecalis phage-cocktail suspension and sustained-release phage formulation were evaluated by viable bacterial count (CFU/mL), histology, scanning electron microscopy (SEM) and 16S genome sequencing of the microbiota of the root canal.

Results

Gelation time for clinical use was established. Low toxicity and a high phage survival rate were recorded. Sustained-release phages reduced E. faecalis in logarithmic (4 logs), stationary (3 logs) and biofilm (4 logs) growth phases. Prolonged anti-biofilm activity of 88% and 95% reduction in biomass and viable counts, respectively, was recorded. Reduction of intracanal viable bacterial counts was observed (99% of enterococci) also seen in SEM. Phage treatment increased Proteobacteria and decreased Firmicutes. Histology showed reduced periapical inflammation and improved healing following phage treatment.

Conclusion

Poloxamer P407 formulated with phages has an effective and long-lasting effect in vitro and in vivo targeting E. faecalis.

Evidence-Based Studies and Perspectives of the Use of Brazilian Green and Red Propolis in Dentistry

This review analyzes the evidence and perspectives of dental use of the green and red propolis produced in Brazil by Apis mellifera L. Multiple applications of propolis were found considering its antibacterial, antifungal, anti-inflammatory, immunomodulatory, antiviral, and healing properties. Its therapeutic effects are mainly due to the presence of alcohols, aldehydes, aliphatic acids, aliphatic esters, amino acids, aromatic acids, aromatic esters, flavonoids, hydrocarbyl esters, ethers, fatty acids, ketones, terpenes, steroids, and sugars. Propolis has been mainly used in dentistry in the composition of dentifrices and mouthwashes. Studies have also demonstrated promising use against dentin hypersensitivity, root canal treatment, Candida albicans, and other microorganisms. Overall review of the literature presented here demonstrated that both Brazilian green and red propolis are effective for the problems of multiple etiologies that affect the oral cavity in different dental specialties.

The Clinical Effectiveness of Calcium Hydroxide in Root Canal Disinfection of Primary Teeth: A Meta-Analysis

BACKGROUND The aim of this research was to systematically analyze the effectiveness of calcium hydroxide compared to formocresol (FC) and camphor phenol (CP) in root canal disinfection of primary teeth. MATERIAL AND METHODS The meta-analysis was based on the participants, interventions, control, outcome (PICO) study design principle and 16 randomized-controlled clinical trials published from January 2000 to August 2018. The data heterogeneity of each study was assessed by the Q-test. The odds ratio and 95% confidence interval (CI) were calculated based on the heterogeneity results by Revman software. RESULTS Sixteen randomized-controlled clinical trials of 3047 primary teeth were included in this meta-analysis. There were significant differences of clinical effectiveness between calcium hydroxide and FC in root canal disinfection of primary teeth (OR=3.37; 95% CI range: 2.54-4.48, P<0.01) and endodontic inter-appointment emergencies (EIAE) after disinfection for 7 days (OR=0.26; 95% CI range: 0.16-0.42, P<0.01). However, there was no statistical difference of EIAE, after disinfection of primary teeth for 48 hours, between calcium hydroxide and FC (OR=0.62; 95% CI range: 0.34-1.11, P=0.11). There were significant differences of clinical effectiveness between the calcium hydroxide and CP in root canal disinfection of primary teeth (OR=5.50; 95% CI range: 3.36-8.98, P<0.01). CONCLUSIONS This meta-analysis indicated that the effectiveness of calcium hydroxide as root canal disinfectant in primary teeth was more effective than that of FC and CP.