Irrigation in endodontics

Guidelines for non-surgical root canal treatment

Guidelines were developed by the Australian Society of Endodontology Inc. with the intent to describe relevant aspects of contemporary evidence-based root canal treatment. The document aims to support clinicians by describing a Standard of Practice in the Australian context. The presented guidelines refer to Competence criteria and Quality standards for the main steps in root canal treatment. While the intent is not to replace individual clinical decision-making, it is envisaged that these periodically reviewable guidelines may help to improve clinical outcomes.

The effect of restorative material selection and cementation procedures on the durability of endocrowns in the anterior teeth: an in-vitro study

OBJECTIVE

To investigate the fracture resistance and failure modalities of anterior endocrown restorations fabricated employing diverse ceramic materials, and bonded using various cementation methodologies.

MATERIALS AND METHODS

Forty maxillary central incisors were divided into two main groups based on the ceramic materials used; GroupI (Zir): zirconia endocrwons (Zolid HT+, Ceramill, Amanngirrbach) and GroupII (E-Max): e-max endocrowns (IPS e.max CAD, Ivoclar Vivadent). Both groups were further split into two subgroups depending on the cementation protocols; subgroup IA "ZirMDP": endocowns cemented with MDP primer + MDP resin cement, subgroup IB (ZirNon-MDP): cemented with MDP primer + non-MDP resin cement, subgroup IIA (E-maxMDP): cemented with MDP primer + MDP resin cement, subgroup IIB (E-maxNon-MDP): cemented with MDP primer + non-MDP resin cement. (n = 10/subgroup). Endocrowns were manufactured using CAD/ CAM. Teeth were subjected to 10,000 thermal cycles. The fracture test was performed at 45o with a palatal force direction until the fracture occurred. Test results were recorded in Newton. The failure mode was examined using a stereomicroscope. A One-way ANOVA test was utilized to compare different groups regarding fracture strength values. Tukey`s Post Hoc was utilized for multiple comparisons.

RESULTS

The comparative analysis of fracture strength across the diverse groups yielded non-significant differences, as indicated by a p-value exceeding 0.05. Nonetheless, an observable trend emerged regarding the mode of failure. Specifically, a statistically significant prevalence was noted in fractures localized within the endocrown/tooth complex below the cementoenamel junction (CEJ) across all groups, except for Group IIB, "E-max Non-MDP," where fractures within the endocrown/tooth complex occurred above the CEJ.

CONCLUSIONS

Combining an MDP-based primer with an MDP-based resin cement did not result in a significant effect on the anterior endocrown fracture strength.

CLINICAL RELEVANCE

Regardless of the presence of the MDP monomer in its composition, adhesive resin cement achieved highly successful fracture strength when used with MDP-based ceramic primers. Additionally, ceramic materials exhibiting elastic moduli surpassing those of dentin are discouraged due to their propensity to induce catastrophic fractures within the tooth structure.

Water-soluble vitamin-E for enhancing fluorescence diagnosis in infected human dentine treated with NaOCl

INTRODUCTION

Bacterial fluorescence methods are of interest in endodontics for informing endpoints for debridement. This study explored potential fluorescence quenching reversal effects of a water-soluble vitamin E conjugate (d-α-Tocopherol polyethylene glycol 1000 succinate, TPGS) when applied to polymicrobial biofilms grown on dentine that had been exposed to sodium hypochlorite (NaOCl) to cause quenching.

METHOD

Extracted human teeth were debrided, embedded in transparent acrylic resin and sectioned. After smear layer removal, tooth dentine sections were inoculated with a polymicrobial inoculum, and cultured for 7 days to create biofilms. Samples (n = 8 per group) were exposed to 1 % or 4 % NaOCl for 2 or 4 min, and then treated with TPGS. Bacterial fluorescence readings under laser excitation at 655 nm were assessed over 10 min using a calibrated DIAGNOdent device. All data were assessed for normality (Kolmogorov-Smirnov test) and analysed with ANOVA followed by Bonferroni post-hoc tests.

RESULTS

NaOCl at both concentrations quenched fluorescence readings of biofilms grown on dentine samples, with a maximal reduction of 40.4 % at 5 min after 4 % NaOCl. Treatment with TPGS gave faster recovery of fluorescence readings compared to the control at 5 and 10 min.

CONCLUSION

The water-soluble antioxidant TPGS partially reversed fluorescence quenching caused by NaOCl. This agent may have value clinically for reducing the time needed for fluorescence readings to recover when NaOCl is used as an irrigant. This will facilitate more accurate assessment of endpoints for canal debridement.

Effects of endodontic root canal irrigants on tooth dentin revealed by infrared spectroscopy: a systematic literature review

BACKGROUND

Root canal irrigation endodontic solutions have effects on the chemistry of dentin. Infrared spectroscopy is a non-destructive chemical characterization method where the strength of absorption often correlates with mineral or organic composition.

OBJECTIVES

To survey effects of commonly used irrigation solutions on the composition of root dentin as detected by widely-available Fourier transform infrared spectroscopy (FTIR) methods.

METHODS

Electronic databases were searched for articles published between 1983 to 2023. After risk of bias assessments (OHAT), studies were grouped according to effects per irrigation solution. Inclusion criteria comprised in vitro studies that used extracted human or bovine teeth, treated by irrigation solutions characterized using FTIR spectroscopy and presenting spectral data. Publications that did not share FTIR spectra were excluded.

RESULTS

A wide range of concentrations, durations, and methodologies have been tested but only 30 out of 3452 studies met our inclusion criteria. Different FTIR methods were used with the Attenuated Total Reflection (ATR) variant being the most common (21 studies). Investigated solutions included sodium hypochlorite (NaOCl), ethylenediaminetetraacetic-acid (EDTA), 1-hydroxyethylidene-1-1-diphosphonic-acid (HEDP), peracetic-acid (PAA), glycolic-acid (GA), and citric-acid (CA) though most focused on NaOCl and EDTA. All solutions had detectable effects on the FTIR signature of dentin. NaOCl mainly affects the organic signatures, revealing reduced amide/phosphate ratios with increasing concentrations. EDTA mainly effects the inorganic component, increasing with time and concentration, yet glycolic acid has stronger effects than EDTA on dentin. Beyond the type of irrigant and dentin exposure durations, concentration and protocol of application had strong effects. There is a lack of studies comparing similar irrigants under conditions that mimic clinical scenarios analyzing bulk sample because FTIR of powder dentin differs from bulk measurements.

SIGNIFICANCE

The ideal root-canal irrigant should combine local disinfection properties with minimal compositional effects on healthy dentin. FTIR methods appear reliable to identify important changes in root dentin chemical composition. Such information can help understand when endodontic irrigation might lead to root degradation or possibly contribute to long term failures such as vertical fractures. Awareness of chemical damage from irrigation procedures may help clinicians select procedures that reduce deleterious effects on the root canal structures.

Postoperative pain after endodontic treatment using 8.25% vs 2.5% sodium hypochlorite in necrotic mandibular molars with apical periodontitis: A randomized double-blind clinical trial

BACKGROUND

This study aimed to evaluate whether the use of 8.25% sodium hypochlorite (NaOCl), compared with the use of 2.5% NaOCl, leads to higher postoperative pain after endodontic treatment.

METHODS

A total of 154 patients were randomly assigned into 2 groups: 8.25% and 2.5% NaOCl. A single-visit endodontic treatment was performed using a standard protocol, varying only the NaOCl concentration. Postoperative pain was assessed using the numeric rating scale at multiple times over 30 days. Overall pain scores over time were explored via multilevel mixed-effects negative binomial regression. The need for pain medication was recorded and compared between groups via the Mann-Whitney U test.

RESULTS

The use of 8.25% NaOCl increased postoperative pain scores over time by 3.48 times compared with the use of 2.5% NaOCl (incident rate ratio [IRR], 3.48; 95% CI, 1.57 to 7.67). Furthermore, the 8.25% NaOCl group exhibited higher pain incidence than the 2.5% NaOCl group during the 12-hour through 3-day period, with scores at these times ranging from 2.21 (IRR, 2.21; 95% CI, 1.35 to 3.62) through 10.74 (IRR, 10.74; 95% CI, 3.74 to 30.87) higher. No difference was detected in the number of analgesic capsules administered between groups.

CONCLUSIONS

The use of 8.25% NaOCl resulted in higher postoperative pain than the use of 2.5% NaOCl, with pain scores increasing by 3.48 times when this solution was used. Furthermore, the 8.25% NaOCl group exhibited higher pain incidence than the 2.5% NaOCl group during the 12-hour through 3-day period.

PRACTICAL IMPLICATIONS

The use of 8.25% NaOCl during endodontic treatment can increase postoperative pain significantly. This clinical trial was registered at the Brazilian Registry of Clinical Trials database (RBR-6vq3hc4).

Endodontic Treatment of Chronic Apical Periodontitis Ameliorates Systemic Inflammation and Restores Impaired Cellular Responses to Insulin in an In Vitro Model

INTRODUCTION

A growing body of research supports an association between periapical inflammation and an increased risk of developing systemic diseases. There is currently no scientific evidence to support a causal effect of inflammation on the onset of insulin resistance (IR) in patients with apical periodontitis (AP). The aim of this in vitro study was to evaluate any association between AP and levels of serum inflammatory factors potentially associated with the onset of IR, and to investigate the effect of root canal treatment (RCT) on these systemic inflammation markers and on the response in vitro to insulin.

METHODS

A total of 27 control subjects and 27 patients with AP were enrolled. Patients with AP underwent RCT and were followed-up 6 and 12 months post-treatment. Enzyme-linked immunosorbent assays were used to evaluate serum levels of proinflammatory cytokines interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor (TNF)-α. The response in vitro to insulin was assessed by measuring glucose consumption in a human pancreatic epithelioid carcinoma cell line treated with sera from healthy and AP subjects.

RESULTS

At baseline AP was associated with significant higher levels of IL-1, IL-6, and IL-8 in the serum of untreated (AP) patients vs controls (P < .001). Glucose consumption decreased in pancreatic cells incubated with baseline serum from patients with AP, in a manner proportional to total cytokines amount. Notably, endodontic treatment was associated with reduced levels of cytokines (P < .001) and improved response to insulin in AP group (P < .001).

CONCLUSIONS

Our findings suggest that AP may promote inflammatory-driven IR in an in vitro model, and that RCT may ameliorate inflammatory mediators in vivo and the cellular response to insulin in vitro.

Influence of different presentation forms of chlorhexidine on contaminated root canals during agitation

This in vitro study aimed to verify the influence of chlorhexidine (CHX) (gel and solution) in association with different activation protocols on disinfection of root canals contaminated with Enterococcus faecalis. In total, 120 lower premolar roots were selected, contaminated and divided into 12 groups according to irrigation technique and substance. Samples were collected before and after each irrigation technique and analysed for colony-forming units (CFU). Three dentin discs were obtained for quantification of viable intratubular cells by using confocal laser scanning microscopy (CLSM). CFU results showed that sonic and ultrasonic were more effective than conventional irrigation. Ultrasonic activation was more effective than sonic for CHX gel (p < 0.05). CLSM showed that either activation was better than conventional in all groups and root canal thirds (p < 0.05). It was concluded that ultrasonic/sonic activation was more effective than conventional techniques and CHX enhanced intratubular dentin decontamination across all irrigation methods.

Irrigant dynamics of a back-to-back double side-vented needle in root canals with various tapers: a computational fluid dynamics study

Understanding the apical pressure and irrigant flow patterns in root canals is crucial for safe and effective irrigation. Therefore, this study aimed to assess the flow characteristics of irrigants in root canal models with varying tapers during final irrigation by employing various needle designs, including a back-to-back double-side-vented needle, through computational fluid dynamics. The root canal model was configured as a closed geometrical cone with a simulated apical zone (size 30) and features tapers of 4%, 6%, and 8%. Three needle types-open-ended needle (OEN), single side-vented needle (SSVN), and double side-vented needle (DSVN)-were investigated. The results indicated that for the 4% taper models, the open-ended needle generated the maximum apical pressure, followed by the double side-vented needle and the single side-vented needle. However, in the 6% and 8% tapering root canal models, the double-side-vented needle applied the lowest maximum apical pressure. Consequently, the DSVN can pose a risk for irrigant extrusion in minimally prepared canals due to heightened apical pressure. In wider canals, the DSVN exhibited lower apical pressure. The maximum irrigant replacement was observed with OEN compared to that of the closed-ended group for both flow rates. Additionally, compared with OENs, closed-ended needles exhibited nonuniform and lower shear wall stress.

Endodontic Treatment of a Mandibular Second Molar Featuring Vertucci Type V Configuration in the Distal Root: A Case Report

Successful root canal treatment relies primarily on thorough shaping, cleaning, and filling of the entire root canal system. Neglecting even a single canal can significantly raise the risk of post-treatment apical periodontitis. While the distal root of mandibular second molars typically has one canal, they can also present with anatomical variations, including the presence of a Vertucci Type V configuration. This article discusses a case in which a Vertucci Type V configuration in a mandibular second molar was effectively identified and treated.

Antibacterial efficacy of silver nanoparticles, sodium hypochlorite, chlorhexidine, and hypochlorous acid on dentinal surfaces infected with Enterococcus faecalis

The purpose of this study was to evaluate the antibacterial effect of silver nanoparticles (AgNPs) against Enterococcus faecalis and compare it with different irrigation solutions. This study was performed using 64 dentin blocks. E. faecalis suspension was dispensed to each sample and incubated under anaerobic conditions at 37°C throughout 21 days. After the inoculation period, the following solutions were added to each group and kept for 5 min: Group 1, 5.25% sodium hypochlorite (NaOCl); Group 2, 2.5% NaOCl; Group 3, 1% NaOCl; Group 4, 2% chlorhexidine (CHX); Group 5, 200 ppm hypochlorous acid (HOCl); and Group 6, AgNPs. The samples of positive control were treated with sterile saline. Biofilm viability assay was performed using the LIVE/DEAD BacLight Bacterial Viability Kit. Samples were examined using confocal laser scanning microscopy, respectively. There was no significant difference between the 5.25% NaOCl, 2.5% NaOCl, and 1%NaOCl groups (p > .05). However, these groups showed statistically higher antibacterial activity than the 2% CHX, 200 ppm HOCl, and AgNP groups. Also, 2% CHX showed greater percentage of dead cells compared with the AgNP and HOCl groups. While AgNPs group showed lower dead cell rate than all NaOCl groups and 2% CHX, it caused higher dead cells than 200 ppm HOCl group. The 200 ppm HOCl group showed the lowest percentage of dead cells (p < .05) Although the antibacterial effect of AgNPs is not as high as NaOCl and CHX, it has considerable bactericidal activity against E. faecalis and can be improved by further studies. RESEARCH HIGHLIGHTS: New antimicrobial approaches for root canal irrigation. Antimicrobial effect of silver nanoparticles against E. faecalis. Elimination of the biofilm layer for the success of endodontic treatment.

Application of Nanomaterials in Endodontics

Recent advancements in nanotechnology have introduced a myriad of potential applications in dentistry, with nanomaterials playing an increasing role in endodontics. These nanomaterials exhibit distinctive mechanical and chemical properties, rendering them suitable for various dental applications in endodontics, including obturating materials, sealers, retro-filling agents, and root-repair materials. Certain nanomaterials demonstrate versatile functionalities in endodontics, such as antimicrobial properties that bolster the eradication of bacteria within root canals during endodontic procedures. Moreover, they offer promise in drug delivery, facilitating targeted and controlled release of therapeutic agents to enhance tissue regeneration and repair, which can be used for endodontic tissue repair or regeneration. This review outlines the diverse applications of nanomaterials in endodontics, encompassing endodontic medicaments, irrigants, obturating materials, sealers, retro-filling agents, root-repair materials, as well as pulpal repair and regeneration. The integration of nanomaterials into endodontics stands poised to revolutionize treatment methodologies, presenting substantial potential advancements in the field. Our review aims to provide guidance for the effective translation of nanotechnologies into endodontic practice, serving as an invaluable resource for researchers, clinicians, and professionals in the fields of materials science and dentistry.

Effect of final irrigation protocols with chitosan nanoparticle and genipin on dentine against collagenase degradation: An ex-vivo study

AIM

Endodontic irrigants may affect the mechanical and chemical properties of dentine. This study evaluated the effects of various final irrigation protocols including the use of chitosan nanoparticle (CSnp) and cross-linking with genipin on the (1) mechanical and (2) chemical properties of dentine against enzymatic degradation.

METHODOLOGY

CSnp was synthesized and characterized considering physiochemical parameters and stability. The root canals of 90 single-rooted teeth were prepared and irrigated with NaOCl. Dentine discs were obtained and divided into groups according to the following irrigation protocols: Group NaOCl+EDTA, Group NaOCl+CSnp, Group NaOCl+EDTA+CSnp, Group NaOCl+CSnp+Genipin, Group NaOCl+EDTA+CSnp+Genipin and Group distilled water. (1) Mechanical changes were determined by microhardness analysis using Vickers-tester. (2) Chemical changes were determined by evaluating molecular and elemental compositions of dentine using Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscope (SEM)/energy dispersive X-ray spectroscopy (EDS) analysis, respectively. All analyses were repeated after the discs were kept in collagenase for 24 h. Data were analysed with repeated measures analysis of variance and Bonferroni correction for microhardness analysis, and Kruskal-Wallis and Wilcoxon tests for FTIR and SEM/EDS analyses (p = .05).

RESULTS

(1) Collagenase application did not have a negative effect on microhardness only in Group NaOCl+EDTA+CSnp+Genipin when compared with the post-irrigation values (p > .05). Post-collagenase microhardness of Group NaOCl+EDTA+CSnp and Group NaOCl+CSnp+Genipin was similar to the initial microhardness (p > .05). (2) After collagenase, Amide III/PO 4 3 - ratio presented no change in Group NaOCl+EDTA+CSnp, Group NaOCl+CSnp+Genipin and Group NaOCl+EDTA+CSnp+Genipin (p > .05), while decreased in other groups (p < .05). Collagenase did not affectCO 3 2 - /PO 4 3 - ratio in the groups (p > .05). There were no changes in the groups in terms of elemental level before and after collagenase application (p > .05).

CONCLUSIONS

CSnp and genipin positively affected the microhardness and molecular composition of dentine. This effect was more pronounced when CSnp was used after EDTA.

Effects of endodontic irrigation solutions on structural, chemical, and mechanical properties of coronal dentin: A scoping review

OBJECTIVE

This review aims to assess structural, chemical, and mechanical properties of coronal dentin after endodontic irrigation.

MATERIALS AND METHODS

Reporting followed the PRISMA extension for scoping reviews. An electronic search was carried out in PubMed, Embase, and Cochrane Library. Records filtered by language and published up to November 4, 2022 were independently screened by two researchers. Studies evaluating structural, chemical, or mechanical properties of human permanent coronal dentin after irrigation within the scope of nonsurgical root canal treatment were included. Data were extracted regarding study type, sample description and size, experimental groups, outcome, evaluation method, and main findings.

RESULTS

From the initial 1916 studies, and by adding 2 cross-references, 11 in vitro studies were included. Seven studies provide ultrastructural and/or chemical characterization, and six assessed microhardness and/or flexural strength. One percent to 8% sodium hypochlorite (NaOCl) and 1%-17% ethylenediaminetetraacetic acid (EDTA) were the most commonly tested solutions, with contact times of 2-240 min (NaOCl) and 1-1440 min (EDTA) being evaluated.

CONCLUSIONS

Overall, the literature is consensual regarding the inevitable impact of NaOCl and chelating agents on coronal dentin, with both deproteinizing and decalcifying effects being concentration- and time-dependent. The alteration of mechanical parameters further confirmed the surface and subsurface ultrastructural and chemical changes.

CLINICAL SIGNIFICANCE

Endodontic treatment success highly depends on restorative sealing. Understanding the result of exposing coronal dentin, the main substrate for bonding, to irrigants' action is crucial. The deproteinizing and decalcifying effects of NaOCl and chelating agents are both concentration- and time-dependent, causing surface and subsurface ultrastructural, chemical, and mechanical alterations.

Sodium hypochlorite against Enterococcus faecalis biofilm in dentinal tubules: effect of concentration, temperature, and exposure time

This study aimed to evaluate the effectiveness of two sodium hypochlorite concentrations at different exposure times and temperatures against Enterococcus faecalis biofilms of varying ages in human dentinal tubules. Dentin blocks were infected with E. faecalis for either 3 days or 3 weeks of incubation. Subsequently, the samples were exposed to sterile water, 2%, and 5.25% sodium hypochlorite for 3 and 10 min at 20 °C and 60 °C . Viability staining and confocal laser scanning microscopy were used to assess the proportion of killed bacteria in the dentinal tubules after exposure. There are no significant differences in the efficacy of E. faecalis killing between 2% sodium hypochlorite at 60 °C for various exposure times and 5.25% sodium hypochlorite at different temperatures or exposure times (P > 0.05). When both solutions were compared at the same temperatures with a 10-min exposure time, no significant differences in the effectiveness of E. faecalis killing between 2% and 5.25% sodium hypochlorite were observed (P > 0.05). To optimize the effectiveness of sodium hypochlorite in killing E. faecalis while minimizing potential damage to root dentin and soft tissue, clinicians should prioritize increasing the temperature or exposure time of sodium hypochlorite, rather than raising its concentration.

Effect of sodium hypochlorite, ethylenediaminetetraacetic acid, and dual-rinse irrigation on dentin adhesion using an etch-and-rinse or self-etch approach

The aim was to investigate the influence of endodontic irrigation solutions and protocols on the micro-tensile bond strength (μTBS) to dentin using an etch-and-rinse (ER) or self-etch (SE) adhesive approach. Eighty extracted human molars were ground to dentin. After pretreating for 27 min (21 min-3 min-3 min) with five different endodontic irrigation protocols (Group 1: NaOCl-EDTA-NaOCl; Group 2: NaOCl-NaOCl-EDTA; Group 3: NaOCl-NaCl-NaOCl; Group 4: Dual Rinse-Dual Rinse-Dual Rinse; Group 5: NaCl-NaCl-NaCl), an ER (Optibond FL, Kerr) or a SE (Clearfil SE Bond, Kuraray) adhesive system was applied. After light-curing, composite build-ups were made and cut into dentin-composite sticks. μTBS and failure modes were analyzed. Nonparametric statistical analyses (α = 0.05) were performed for comparison of the five groups within each type of adhesive as well as between the two adhesive systems used. The use of an ER instead of a SE adhesive system resulted in significantly higher μTBS for all irrigation protocols except for group 1 (NaOCl-EDTA-NaOCl) and 2 (NaOCl-NaOCl-EDTA). A statistical difference between the five different endodontic irrigation protocols was only found within the SE adhesive group, where group 1 (NaOCl-EDTA-NaOCl) achieved highest values. The use of an ER adhesive system cancels out the effect of the endodontic irrigation solution. The highest μTBS was achieved when using a NaOCl-EDTA-NaOCl-irrigation protocol in combination with Clearfil SE Bond, which shows that the selection of the endodontic irrigation should match the corresponding SE adhesive system.

Radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using two different root canal irrigants. A prospective cohort study

AIM

The aim of this prospective cohort study was to compare the radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using either 1% sodium hypochlorite (NaOCl) or 2% chlorhexidine digluconate (CHX) for root canal irrigation.

MATERIALS AND METHODS

In the years from 2013 to 2015 standard irrigation varied by semester between NaOCl and CHX at the Department of Endodontics at the Faculty of Dentistry. During that time, 912 teeth received treatment for apical periodontitis in 744 patients, of whom 532 responded to the request for a 1-year follow-up. Only one tooth per person (the most distally located) were included; 285 teeth treated with NaOCl and 247 with CHX. One hundred cases were then randomly sampled from each irrigation group and analysed for outcome by periapical index (PAI) scoring using criteria for success, uncertain and failure. Clinical and other radiographic parameters were scored or recorded and analysed for associations with radiographic outcome using chi-square, ANOVA and regression analyses.

RESULTS

Success rates (PAI score 1 or 2 at control) were nearly identical for the two irrigation liquids. The use of irrigating solution also did not significantly influence the outcome in chi-square analyses of subgroups of teeth or regression analyses with other variables included. Ordinal regression analysis established that preoperative lesion size or preoperative PAI score were significantly associated with outcome, and teeth in the mandible had significantly better outcomes than in the maxilla.

CONCLUSIONS

No significant differences in the radiographic outcome using either 1% NaOCl or 2% CHX as irrigants were found. The outcome was better for teeth with small lesions or lower PAI scores at completion of treatment and for mandibular teeth.

Endodontic sealers after exposure to chlorhexidine digluconate: An assessment of physicochemical properties

OBJECTIVES

Final root canal irrigation should ideally maintain the physicochemical stability of root canal sealers. We seek to assess the effect of contact with 2% chlorhexidine digluconate (CHX) on the physicochemical properties of AH Plus, BioRoot™ RCS, and Pulp Canal Sealer (PCS).

METHODS

Mixed sealers were placed in cylindrical teflon molds and allowed to set for 1.5x the manufacturers' setting time. Half of the specimens had their free surface in contact with CHX for the first minute of their setting period. Solubility, radiopacity, surface roughness, microhardness and wettability of the sealers were assessed up to 28 days after setting. Elemental analysis of sealer surfaces and their leachates together with pH measurements were also performed. Appropriate parametric and non-parametric analysis with post hoc tests were performed (p < 0.05).

RESULTS

Exposure to CHX had no effect on solubility and radiopacity of all sealers. CHX altered the surface roughness of PCS and BioRoot RCS (p < 0.05). Contact with CHX reduced the microhardness of AH Plus and PCS (p < 0.05). AH Plus was more hydrophilic after CHX contact, whereas PCS became more hydrophobic (p < 0.05). AH Plus and PCS surfaces appeared to adsorb CHX as exhibited by chlorine peaks after contact with CHX. Sealer leachates' alkalinity was not affected. CHX increased elution of silicon and zirconium for BioRoot and zinc for PCS leachates.

SIGNIFICANCE

In our study, CHX affected sealers' physicochemical properties to various extents. Further studies are needed to confirm the obtained results by investigating various final irrigation strategies and correlating to biological properties.

Endodontic Treatment of a Maxillary Incisor Tooth in a Chimpanzee (Pan troglodytes)

Chimpanzees (Pan troglodytes) with teeth severely damaged by dental caries and/or periodontal disease are often managed with medication and/or tooth extraction. A common endodontic treatment for severely decayed teeth in a 26-year-old female chimpanzee is reported. The left maxillary central incisor tooth had lost its crown, probably due to trauma that was not recent, and it had a fistula most likely due to chronic apical periodontitis. The diagnosis was confirmed radiographically before treatment. To treat the infected root canal, endodontic treatment used in humans was adapted for a chimpanzee. After the treatment, the tooth was sealed using an adhesive resin composite. At 11-years post-treatment, there were no signs of recurrence of the lesion or of failure of the tooth seal. The results of this case report suggest that common endodontic treatments used in humans are also effective in chimpanzees.

In vitro efficacy of Er:YAG laser-activated irrigation versus passive ultrasonic irrigation and sonic-powered irrigation for treating multispecies biofilms in artificial grooves and dentinal tubules: an SEM and CLSM study

BACKGROUND

Multispecies biofilms located in the anatomical intricacies of the root canal system remain the greatest challenge in root canal disinfection. The efficacy of Er:YAG laser-activated irrigation techniques for treating multispecies biofilms in these hard-to-reach areas has not been proved. The objective of this laboratory study was to evaluate the effectiveness of two Er:YAG laser-activated irrigation techniques, namely, photon-induced photoacoustic streaming (PIPS) and shock wave-enhanced emission photoacoustic streaming (SWEEPS), in treating multispecies biofilms within apical artificial grooves and dentinal tubules, in comparison with conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), and sonic-powered irrigation (EDDY). Two types of multispecies root canal biofilm models were established in combination with two assessment methods using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) with the aim to obtain more meaningful results.

METHODS

Ninety extracted human single-rooted premolars were chosen for two multispecies biofilm models. Each tooth was longitudinally split into two halves. In the first model, a deep narrow groove was created in the apical segment of the canal wall. After cultivating a mixed bacterial biofilm for 4 weeks, the split halves were reassembled and subjected to five irrigation techniques: CNI, PUI, EDD, PIPS, and SWEEPS. The residual biofilms inside and outside the groove in Model 1 were analyzed using SEM. For Model 2, the specimens were split longitudinally once more to evaluate the percentage of killed bacteria in the dentinal tubules across different canal sections (apical, middle, and coronal thirds) using CLSM. One-way analysis of variance and post hoc multiple comparisons were used to assess the antibiofilm efficacy of the 5 irrigation techniques.

RESULTS

Robust biofilm growth was observed in all negative controls after 4 weeks. In Model 1, within each group, significantly fewer bacteria remained outside the groove than inside the groove (P < 0.05). SWEEPS, PIPS and EDDY had significantly greater biofilm removal efficacy than CNI and PUI, both from the outside and inside the groove (P < 0.05). Although SWEEPS was more effective than both PIPS and EDDY at removing biofilms inside the groove (P < 0.05), there were no significant differences among these methods outside the groove (P > 0.05). In Model 2, SWEEPS and EDDY exhibited superior bacterial killing efficacy within the dentinal tubules, followed by PIPS, PUI, and CNI (P < 0.05).

CONCLUSION

Er:YAG laser-activated irrigation techniques, along with EDDY, demonstrated significant antibiofilm efficacy in apical artificial grooves and dentinal tubules, areas that are typically challenging to access.

Did in-between rinsing and agitating with distilled water prevents precipitate formation by the interaction between sodium hypochlorite and chlorhexidine canal irrigants?

The interaction of sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) produces an orange-brown precipitate. The present study evaluated the influence of distilled water (H2 O) in different irrigation protocols designed to prevent the formation of precipitate with NaOCl and CHX. Fifty canine teeth were instrumented and split longitudinally. The canal was examined with a stereomicroscope and photographed by canal-thirds. The tooth halves were repositioned and distributed randomly into five groups, according to the final irrigation protocol (n = 10): G1 (control)-Ethylenediaminetetraacetic acid (EDTA) + NaOCl + CHX, conventional irrigation (CI); G2-EDTA + NaOCl + CHX, activated with passive ultrasonic irrigation (PUI); G3-EDTA (PUI) + NaOCl (PUI) + H2 O (CI) + CHX (PUI); G4-EDTA + NaOCl + H2 O + CHX (PUI); G5-EDTA (PUI) + NaOCl (PUI) + H2 O (continuous ultrasonic irrigation [CUI]) + CHX (PUI). The specimens were evaluated with a stereomicroscope and scanning electron microscope (SEM). Energy dispersive x-ray spectroscopy analysis was performed to identify the elemental profile of the irrigated canal walls. The images were scored according to the extensiveness of precipitate. Data were analyzed (Kruskal-Wallis test, α = 5%). Under the stereomicroscope, G1 had significantly higher scores than all the other groups in all canal-thirds (p < .05). All four experimental groups showed similar scores (p > .05). There were no significant differences in precipitate formation among root-thirds in intragroup analysis (p > .05). Upon SEM examination, overall, only G5 had lower scores than G1 (p < .05). Analysis by canal-thirds showed no significant difference among groups and among canal-thirds in the intragroup analysis (p > .05). G1 showed high Cl peaks. In-between irrigation with H2 O activated by CUI is effective in preventing precipitate formation during canal debridement with NaOCl and CHX. RESEARCH HIGHLIGHTS: Continuous ultrasonic irrigation with distilled water was capable to prevent the precipitate formation. The precipitate can be classified as a chemical smear layer.

The comparative of chitosan and chitosan nanoparticle versus ethylenediaminetetraacetic acid on the smear layer removal: A systematic review and meta-analysis of in vitro study

The purpose of this systematic review of meta-analysis was to compare the effectiveness of removing the smearing layer using EDTA versus Chitosan (Ch) and Chitosan nanoparticles (Ch-NPs). A search was performed in four electronic databases (Web of Science, PubMed, Scopus, and Cochrane). The included studies were assessed by two reviewers using Joanna Briggs Institute's critical appraisal checklist for the quasi-experimental studies. Outcomes obtained by scanning electron microscopy (SEM) and conventional methods were presented as standardized mean differences alongside 95% confidence intervals. Seven investigations employed 212 single-root teeth. In the apical section (p = .317, 95% CI = -0.820 to 0.266, Tau2  = 0.387), middle segment (p = .914, 95% CI = -1.019 to 0.912, Tau2  = 1.027), and coronal segment (p = .277, 95% CI = -1.008 to 0.289, Tau2  = 0.378). This meta-analysis found no difference between Ch, Ch-NPs, and EDTA in removing the smear layer in the three segments. This systematic review is designed to show evidence related to the PICO question, in which our outcome is smear layer removal and not the clinical success of such a treatment. RESEARCH HIGHLIGHTS: The study aimed to compare the effectiveness of chitosan and chitosan nanoparticles with ethylenediaminetetraacetic acid (EDTA) in removing the smear layer, a layer of debris and organic material on the tooth surface, through a systematic review and meta-analysis. The removal of the smear layer is crucial for successful dental treatments, as it enhances the adhesion of restorative materials and improves the penetration of antimicrobial agents into dentinal tubules. The researchers conducted a systematic review and meta-analysis, searching various databases of electron microscopy results for relevant in vitro studies comparing the effects of chitosan or chitosan nanoparticles with EDTA on smear layer removal. The results encourage further exploration of chitosan and chitosan nanoparticles for clinical use in dentistry, while considering their specific applications and long-term effects.

Formulations of NaOCl-based in liquid, gel form or with surfactants on dentin deproteinization before fiber post cementation

The objective of the study was to evaluate the effects of dentin deproteinization protocols for post space using different formulations containing sodium hypochlorite before fiber post cementation with self-adhesive resinous cement. The groups were divided according to the irrigation protocol (DWC, SHS, SHT and SHG). The residue cleanliness, bond strength, adhesive failure pattern, and tag formation at the adhesive interface between the self-adhesive cement and the dentin were evaluated. For this, analysis in scanning electron microscope, push-out test and confocal laser scanning microscopy were performed. The SHT protocol showed the highest residue cleanliness on the dentin surface of the post space (p<0.05). In addition, SHT protocol showed highest bond strength and tag formation in the cervical and middle thirds (p<0.05). Dentin deproteinization with sodium hypochlorite with surfactant provided the best dentin cleaning of residues, bond strength and tag formation after cementation of the fiber post with self-adhesive cement.

Can Heated Distilled Water Effectively Prevent Precipitate Formation between NaOCl and CHX?

Introduction

The present study aimed to investigate the capacity of different irrigation protocols using heated distilled water at 65°C (HDW), in preventing the formation of the brown-orange precipitate observed after the interaction between sodium hypochlorite (NaOCl) and chlorhexidine (CHX).

Methods

Forty human canines were selected, prepared, and cleaved in two halves. Images of delimited areas in each root canal thirds were obtained through a stereomicroscope (16x and 40x). After reassembly, the teeth were distributed into four groups (n = 10) according to the final irrigation protocol: G1 (no HDW): EDTA + NaOCl + CHX with conventional irrigation (CI); G2 (HDW + CI): EDTA with passive ultrasonic irrigation (PUI) + NaOCl (PUI) + HDW (CI) + CHX (PUI); G3 (HDW + PUI): EDTA + NaOCl + HDW + CHX with PUI; G4 (HDW + CUI): EDTA (PUI) + NaOCl (PUI) + HDW with continuous ultrasonic irrigation (CUI) + CHX (PUI). After irrigation, the teeth were re-separated and images of the same delimited areas were obtained again. Scores were assigned according to the amount of precipitate observed, comparing the initial and final images. The data were submitted to Kruskal-Wallis, Dunn and Friedman statistical tests (α = 5%).

Results

G1(no HDW) showed the highest scores in the analysis between groups (p < 0.001), with a greater amount of precipitate in the cervical and medium thirds (p < 0.001). The thirds of the other experimental groups did not differ from each other (p > 0.05).

Conclusion

The intermediate irrigation with heated distilled water at 65°C prevented the formation of brown-orange precipitate, regardless of the use of ultrasonic activation (PUI or CUI).

Influence of pulse energy, tip design and insertion depth during Er:YAG-activated irrigation on cleaning efficacy in simulated severely curved complex root canal systems in vitro

AIM

To investigate the influence of pulse energy, tip geometry and tip position in simulated 3D-printed root canals with multiple side canals at different levels in all directions on the cleaning performance of laser-activated irrigation (LAI) compared to sonic activation (EDDY) and conventional needle irrigation (NI).

METHODOLOGY

3D-printed root canal models (25/.06, length 20 mm, curvature 60°, radius 5 mm) with side canals (diameter 0.2 mm) at 2, 5 and 8 mm from the apex were filled with coloured biofilm-mimicking hydrogel. LAI (Morita AdvErL Evo, Kyoto, Japan) was performed with six settings (n = 20; pulse-energy, pulses per second [PPS], tip position): LAI1 (50 mJ, 25 PPS, P400FL, canal entrance [CE]), LAI2 (same as LAI1, but insertion depth 9 mm before the apical endpoint [AE] [corresponding to 1 mm above the first lateral canals]), LAI3 (80 mJ, 25 PPS, P400FL, 9 mm before AE), LAI4 (same as LAI 3, but at CE) for 3 × 20 s each, LAI5 (50 mJ, 25 PPS, P400FL 2 × 20 s, CE & R200T (30 mJ, 25 PPS, 1 × 20 s, 9 mm before AE), LAI6 (30 mJ, 25 PPS, R200T, 9 mm before AE, 3 × 20 s). A continuous irrigation (3 mL/20 s) using distilled water accompanied the irrigation cycles. NI and EDDY (3 × 20 s each; 3 mL/20 s irrigation, insertion AE minus 1 mm, amplitude 4 mm) served as control groups. Biofilm-mimicking hydrogel removal (ImageJ, NIH) was assessed for the entire system, the central canal and the lateral canals using standardized photographs with a microscope (Expert DN, Müller-Optronic) and statistically analysed was performed using Kruskal-Wallis and Dunn tests (p = .05). Irrigant extrusion beyond the foramina was also recorded.

RESULTS

LAI2 (99.08%; interquartile range [IQR]: 96.85-100.00) and LAI3 (97.50%; 96.24-100.00) achieved the significantly best and LAI6 (80.08%; 73.41-84.69) the significantly worst removal of hydrogel from the entire root canal system amongst all LAI configurations (p < .05). There were no significant differences between LAI6, EDDY (72.89%; 67.49-76.22) and manual irrigation (54.39%; 51.01-56.94) (p > .05). R200T laser tip caused significantly more often irrigant extrusion than all other techniques (p < .05).

CONCLUSION

Tip design, energy settings, and the positioning of the laser tip below the canal entrance caused an improvement in cleaning performance of the LAI. However, the small R200T tip created significantly more procedural errors (irrigant extrusion) due to higher concentrated energy.

The Effect of Combined Ultrasonic Tip and Mechanized Instrumentation on the Reduction of the Percentage of Non-Instrumented Surfaces in Oval/Flat Root Canals: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the effectiveness of the ultrasonic tip associated with mechanized instrumentation in reducing the percentage of non-instrumented surfaces of human teeth with oval or flattened root canals. The study followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Pubmed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Embase, Web of Science, and Cochrane Library were searched for literature published till October 2022. Only in vitrostudies were included, which compared conventional mechanized endodontic treatment alone against conventional endodontic treatment in association with ultrasonic tips, evaluating the reduction in the percentage of non-instrumented walls (computed microtomography). Four studies were eligible for qualitative and quantitative analysis. The majority of the studies scored low for risk of bias. The meta-analysis comparing protocols demonstrated a reduced percentage of non-instrumented walls in groups using ultrasonic tips after the conventional mechanized technique (p<0.01) with a confidence interval of 1.04 (95%CI: 0.59, 1.50). The ultrasonic tip associated with mechanized instrumentation demonstrates a significant reduction in the percentage of non-instrumented surfaces in oval or flattened canals.

Temporary Root Canal Obturation with a Calcium Hydroxide-Based Dressing: A Randomized Controlled Clinical Trial

Successful bacterial inactivation or elimination is essential for successful outcomes in endodontics. This study investigated the efficacy of a calcium hydroxide paste (Ca(OH)2) as a temporary medical dressing for 1 week after chemomechanical root canal treatment (CMRCT). Microbiological samples from 26 patients were collected after endodontic emergency treatment as follows: (1) removal of the provisional filling material; (2) CMRCT; (3) irrigation with sodium hypochlorite I (3%); (4) medicinal insertion of Ca(OH)2; and (5) irrigation with sodium hypochlorite II (3%). A microbiological examination was carried out after the specimens had been taken from the root canals via saline and sterile paper points. CMRCT resulted in a significant reduction in total bacterial load (TBL) in the root canal (p < 0.05). Additional irrigation (3) resulted in a further significant reduction in TBL (p < 0.05). In contrast, Ca(OH)2 medication did not prevent the bacterial load from returning to the previous level immediately after CMRCT, but did not increase above that level either (p < 0.05). However, the increase in TBL was significant (p < 0.05) in comparison with the disinfection groups (I/II). Administration of Ca(OH)2 for 1 week shows that in combination with an additional disinfection procedure, an increase in TBL must be expected, but not above the level of conditions after CMRCT.

In Vitro Assessment of SWEEPS and Antimicrobial Photodynamic Therapy Alone or in Combination for Eradicating Enterococcus faecalis Biofilm in Root Canals

OBJECTIVES

This study investigates the efficacy of antimicrobial photodynamic therapy (aPDT) using riboflavin and a blue diode laser (BDL), combined with shock wave-enhanced emission photoacoustic streaming (SWEEPS), against Enterococcus faecalis.

MATERIALS AND METHODS

A total of 48 extracted single-rooted human teeth were used. The root canals were instrumented, sealed at their apices, had the smear layer removed, and then underwent autoclave sterilization. Subsequently, each canal was inoculated with E. faecalis bacterial suspension and allowed to incubate for ten days. After confirming the presence of biofilms through scanning electron microscopy (SEM) in three teeth, the remaining teeth were randomly allocated into nine groups, each containing five teeth: control, 5.25% sodium hypochlorite (NaOCl), BDL, SWEEPS + normal saline, SWEEPS + NaOCl, riboflavin, riboflavin + SWEEPS, riboflavin + BDL, and riboflavin + BDL + SWEEPS. After the treatment, the numbers of colony-forming units (CFUs)/mL were calculated. The data were analysed using one-way ANOVA followed by Tukey's test for comparisons.

RESULTS

All groups, with the exception of the BDL group, exhibited a significant reduction in E. faecalis CFU/mL when compared to the control group (p < 0.001). The difference in CFU/mL value between riboflavin + BDL + SWEEPS and riboflavin + SWEEPS was significant (p = 0.029), whereas there was no significant difference between riboflavin + BDL + SWEEPS and riboflavin + BDL (p = 0.397). Moreover, there was no statistically significant difference between the riboflavin + SWEEPS group and the riboflavin + BDL group (p = 0.893).

CONCLUSIONS

The results demonstrated that combining the SWEEPS technique with riboflavin as a photosensitizer activated by BDL in aPDT effectively reduced the presence of E. faecalis in root canals.

Influence of Chitosan 0.2% in Various Final Cleaning Methods on the Bond Strength of Fiberglass Post to Intrarradicular Dentin

The purpose of this study was to analyze the influence of Chitosan 0.2% in various final cleaning methods on the bond strength of fiberglass post (FP) to intrarradicular dentin. Ninety bovine incisors were sectioned to obtain root remnants measuring 18 mm in length. The roots were divided: G1: EDTA 17%; G2: EDTA 17% + PUI; G3: EDTA 17% + EA; G4: EDTA 17% + XPF; G5: Chitosan 2%; G6: Chitosan 2% + PUI; G7: Chitosan 2% + EA; G8: Chitosan 2% +XPF. After carrying out the cleaning methods, the posts were installed, and the root was cleaved to generate two disks from each root third. Bond strength values (MPa) obtained from the micro push-out test data were assessed by using Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests for multiple comparisons (α = 5%). Differences were observed in the cervical third between G1 and G8 (p = 0.038), G4 and G8 (p = 0.003), G6 and G8 (p = 0.049), and Control and G8 (p = 0.019). The final cleaning method influenced the adhesion strength of cemented FP to intrarradicular dentin. Chitosan 0.2% + XPF positively influenced adhesion strength, with the highest values in the cervical third.

Injectable Methacrylated Gelatin Hydrogel for Safe Sodium Hypochlorite Delivery in Endodontics

Keeping sodium hypochlorite (NaOCl) within the root canal is challenging in regenerative endodontics. In this study, we developed a drug delivery system using a gelatin methacryloyl (GelMA) hydrogel incorporated with aluminosilicate clay nanotubes (HNTs) loaded with NaOCl. Pure GelMA, pure HNTs, and NaOCl-loaded HNTs carrying varying concentrations were assessed for chemo-mechanical properties, degradability, swelling capacity, cytocompatibility, antimicrobial and antibiofilm activities, and in vivo for inflammatory response and degradation. SEM images revealed consistent pore sizes of 70-80 µm for all samples, irrespective of the HNT and NaOCl concentration, while HNT-loaded hydrogels exhibited rougher surfaces. The hydrogel's compressive modulus remained between 100 and 200 kPa, with no significant variations. All hydrogels demonstrated a 6-7-fold mass increase and complete degradation by the seventh day. Despite an initial decrease in cell viability, all groups recovered to 65-80% compared to the control. Regarding antibacterial and antibiofilm properties, 12.5 HNT(Double) showed the highest inhibition zone on agar plates and the most significant reduction in biofilm compared to other groups. In vivo, the 12.5 HNT(Double) group displayed partial degradation after 21 days, with mild localized inflammatory responses but no tissue necrosis. In conclusion, the HNT-NaOCl-loaded GelMA hydrogel retains the disinfectant properties, providing a safer option for endodontic procedures without harmful potential.

The effect of the irrigant activation protocol on postoperative pain in maxillary incisors with asymptomatic apical periodontitis: A three-arm randomized clinical trial

OBJECTIVES

This study aimed to compare the effects of three irrigation activation systems (IAS) on postoperative pain (PP) in activating three final irrigants: sodium hypochlorite 5.25%, ethylenediaminetetraacetic acid 17%, and chlorhexidine 2%.

MATERIALS AND METHODS

This parallel randomized clinical trial included referred patients with asymptomatic large-sized apical lesion incisors. A standard method was followed in the canal cleaning and shaping for all included patients in the study. Then, the patients were randomly assigned (1:1 allocation) into three groups: G1 (n = 20) with passive ultrasonic irrigation activation; G2 (n = 20) with XP-Endo Finisher file activation; and G3 (n = 20) with diode laser (810 nm) activation. PP was estimated in all groups using a visual analog scale after 1, 3, 7, and 14 days of treatment. Comparisons between the groups were made using the Kruskal-Wallis test, whereas the Mann-Whitney U test was used in the pairwise comparisons.

RESULTS

Sixty patients were followed-up in this trial. There were significant differences between the groups in terms of PP After 1, 3, and 7 days of treatment (p = 0.002, p = 0.017, and p = 0.006, respectively). On the first day of treatment, G3 showed the lowest PP compared with G1 and G2 (p = 0.007 and p = 0.001, respectively). On the third day of treatment, G3 showed less PP compared with G2 (p = 0.005). On the seventh day of treatment, G2 showed the highest PP compared with G1 and G3 (p = 0.012 and p = 0.003, respectively).

CONCLUSIONS

The XP-Endo Finisher file caused the highest PP level especially in the next day and 3 days of the treatment, whereas the diode laser had the lowest PP level during the first week of treatment. It is noteworthy that PP disappeared completely after 2 weeks of treatment with all three IASs.

TRIAL REGISTRATION

The trial was registered in the ISRCTN registry (Trial ID: SRCTN99457940).

Enterococcus faecalis in secondary apical periodontitis: Mechanisms of bacterial survival and disease persistence

Enterococcus faecalis is a commensal bacterium commonly found in the human gastrointestinal tract. However, in individuals with compromised immune systems, the pathogen can lead to severe illness. This opportunistic pathogen is associated with secondary apical diseases and is adept at resisting antibiotics and other forms of treatment because of its numerous virulence factors. Enterococcus faecalis is capable of disrupting the normal functions of immune cells, thereby hindering the body's ability to eradicate the infection. However, intensive research is needed in further understanding the adverse immunomodulatory effects of E. faecalis. Potential strategies specific for eradicating E. faecalis have proven beneficial in the treatment of persistent secondary apical periodontitis.

Evaluation of the Anti-microbial Efficacy of a Novel Endodontic Irrigant Against Enterococcus faecalis: An In Vitro Study

INTRODUCTION

Enterococcus faecalis is a constant microbiome that plays an inevitable role in the etiology of peri radicular lesions after endodontic treatment, chronic and, apical periodontitis and, recently, in periimplantitis. The effective biomechanical preparation and the use of potent irrigating solutions will permit bacterial neutralization and toxin inactivation, leading to the success of endodontic treatment. This study aimed to evaluate the "anti-microbial" efficacy of simvastatin (SMV) against E. faecalis as an endodontic irrigant.

MATERIALS AND METHODS

In this invitro experimental study, the antimicrobial efficacy of SMV was evaluated against E. faecalis using the agar diffusion method. The samples were divided randomly into the following groups. GROUP 1: SMV solution 1 μM/L concentration, GROUP 2: SMV solution 5 μM/L concentration, GROUP 3: SMV solution 10 μM/L concentration, GROUP 4: 2% chlorhexidine gluconate (CHX) solution (positive control), and GROUP 5: normal saline (negative control). Linear measurement was done by measuring the zones of inhibition around the medicaments in the cavities in millimeters. Results were tabulated.

RESULTS

The results of the study have shown the zone of inhibition of Group 4 (2% CHX solution) is 19 mm, which demonstrated the best outcome. When comparing the test samples, Group 3 (SMV solution 10 M/L concentration) has the best zone of inhibition, measuring 14 mm, followed by Group 2 (SMV solution 5 M/L concentration), which is 9 mm.

CONCLUSION

The results of this in vitro study have proven that SMV's anti-microbial activity, albeit less potent than CHX in this in vitro investigation, has demonstrated that it can be utilized as an efficient endodontic irrigant.

Evaluation of the effects of different chelation agents on root dentin roughness

Successful root canal treatment requires effective irrigation of the entire root canal system. While chelating agents support irrigation, they can also alter physicochemical properties of the root dentin structure. The aim of this study is to evaluate the effect of different chelation agents on root dentin roughness. Twenty-five extracted maxillary incisors were used in this study. Samples were separated longitudinally and divided into five groups: distilled water, NaOCl, ethylenediaminetetraacetic acid (EDTA), phytic acid and citric acid (CA). Atomic force microscope and energy dispersive X-ray spectroscopy analyses were used for analysing. One-way analysis of variance and Turkey tests were used in the statistical analysis of the study. EDTA, CA and phytic acid solutions increased the roughness and phytic acid and CA solutions decreased the Ca/P ratio in dentin tissue. No statistical difference was observed in the other groups. The decrease of Ca/P ratio should be taken under consideration during irrigation. The increase in surface roughness may provide clinical benefit by supporting the adhesion of the root canal filling materials to the dentin surface.

Traditional and Recent Root Canal Irrigation Methods and Their Effectiveness: A Review

According to contemporary dental standards, the primary goal of endodontic therapy is the chemo-mechanical cleaning of the complex root canal system. Watering root canals with approved solutions and activating them are essential parts of this operation. This review outlines various irrigant activation methods for root canal therapy. Specifically, a comparison among the methods of manual dynamic activation, sonics (subsonic, sonic, and ultrasonic), internal heating, and lasers, was conducted. The results in this work were gathered using Scopus, Web of Science, Google Scholar, and PubMed databases by searching the following keywords: sodium hypochlorite, cleaning, activation, and irrigation methods. The present work concluded that the use of irrigant activation has a greater benefit than its absence. Regardless, it is impossible to point to a single effective activation method.

Quantitative Insight into PCA Formation following Different Chlorhexidine Activation Methods in Endodontic Treatment

The aim of the study was a quantitative analysis of p-chloroaniline (PCA) formation during 2% CHX activation with US and MDI methods in a root canal-like environment with the HPLC-DAD method and, thus, a safety assessment of US and MDI agitation of CHX in endodontic treatment. Two percent CHX was activated with the US method using ISO 30 and 35 K-file, and the MDI method using ISO 30.06 and 35.06 GP cones for 15, 30, 60, and 90 s. PCA concentration was assessed with the HPLC-DAD method. PCA concentration was also assessed for 2% CHX after 0, 3, 18, and 21 days of storage in ambient conditions. PCA was detected in all samples in all methods of activation. The concentration of PCA was dependent on time of activation in US ISO 30 and ISO 35 group (p < 0.05). In the MDI ISO 30.06 and ISO 35.06 groups, a similar trend was observed but without statistical significance (p > 0.05). PCA was detected in shelf-stored 2% CHX and the concentration was related to the time of storage. PCA is released after CHX activation with US and MDI, but mean concentrations are not higher than those observed from self-degradation of shelf-stored 2% CHX.

Biofilm Removal from In Vitro Narrow Geometries Using Single and Dual Pulse Er:YAG Laser Photoacoustic Irrigation

The disinfection and removal of biofilm from titanium dental implants remains a great challenge in oral medicine. Here we present results of novel photoacoustic irrigation laser modalities for biofilm removal in model geometries mimicking the peri-implant pocket. The efficacy of single pulse (Er:YAG-SSP) and dual pulse (Er:YAG-AutoSWEEPS) photoacoustic irrigation modalities were determined for Enterococcus faecalis biofilm decontamination from titanium surfaces in narrow cylindrical and square gap geometries. The density of bacteria as well as the number of live bacteria were determined prior and after different photoacoustic treatments. Both SSP and AutoSWEEPS photoacoustic irrigation techniques removed at least 92% of biofilm bacteria during the 10 s photoacoustic treatment. The effectiveness of cleaning was better in the narrow square gap geometry compared to the cylindrical geometry. The dual pulse Er:YAG-AutoSWEEPS photoacoustic irrigation showed better results compared to SSP modality. No chemical adjuvants were needed to boost the effectiveness of the photoacoustic irrigation in the saline solution. The results imply that photoacoustic irrigation is an efficient cleaning method for debridement and decontamination in narrow geometries and should be considered as a new therapeutic option for the treatment of peri-implant diseases.

Dual effectiveness of a novel all-in-one endodontic irrigating solution in antibiofilm activity and smear layer removal

The continuous destruction of dental hard tissues increases the risk of bacterial invasion, which leads to pulp infections. Irrigation is critical for successful root canal treatment in terms of infection control. However, no single irrigant covers all of the functions demanded, including antibiofilm and tissue-dissolving activities. The aim of this study was to investigate the antimicrobial properties of Triton, an all-in-one irrigant, on Enterococcus faecalis and multispecies oral biofilms in dentin canals, as well as its ability to remove the smear layer. Dentin blocks (192 specimens) were prepared from single-root human teeth and then assigned to 48 groups (24 groups for each biofilm type). Serial centrifugation was used for bacterial introduction into dentinal tubules. After 3 weeks, half of the specimens were created a uniform smear layer. The following treatments were applied: short time (separate): Triton, 6% NaOCl, 2% NaOCl, and water (all for 3 min); short time (combined): Triton (3 + 1 min), 6% NaOCl +17% EDTA (3 + 1 or 2 + 1 min), and 2% NaOCl +17% EDTA (3 + 1 min); and long time: Triton (3 + 3 min), 6% NaOCl (5 min), 6% NaOCl +17% EDTA (5 + 1 min), and water (3 + 3 min). Confocal laser scanning microscopy and scanning electron microscopy were employed to examine the antimicrobial activity and smear layer removal, respectively. The results revealed that despite the absence or presence of the smear layer, Triton (3 + 3 min) showed the highest killing for both tested biofilms (61.53%-72.22%) among all groups (p < 0.05). Furthermore, the smear layer was removed by Triton after 3 + 3 min, exposing open dentin canals. These findings demonstrated that Triton can provide dual benefits of antibiofilm and smear layer removal capabilities simultaneously, indicating a simplified and effective strategy for application in root canal treatment.

Prevalence of postoperative pain after endodontic treatment using low and high concentrations of sodium hypochlorite: a systematic review and meta-analysis

OBJECTIVES

To determine the prevalence of postoperative pain after endodontic treatment using low (LC) and high (HC) concentrations of sodium hypochlorite (NaOCl).

MATERIALS AND METHODS

Six databases and the grey literature were searched to identify randomized clinical trials that evaluated postoperative pain after endodontic treatment using NaOCl. NaOCl concentrations were dichotomized into 'LC' (0.5% to 3%) and 'HC' (≥ 5%) and a proportion meta-analysis was applied to determine the postoperative pain prevalence: overall and according to pain intensity and postoperative time. The prevalence of patients using pain control medication was also determined. A significance level of 5% and a random effect model were applied for data analysis. Between-study heterogeneity was assessed by I2 index. Risk of bias (RoB) was assessed using the Cochrane Risk-of-Bias 2.0 tool. The certainty of evidence was assessed using the GRADE approach.

RESULTS

Ten studies were included in the review and eight in the meta-analysis. The overall prevalence of postoperative pain was 45% in LC and 39% in HC. The prevalence of pain in LC and HC after 24 h was 25% and 40%, respectively. After 48 h, the prevalence decreased to 10% in LC and 25% in HC. 'Absent pain' was the most prevalent score. The prevalence of patients who used medication was 9% in LC and 15% in HC. Three studies were classified as 'high RoB', five as 'low RoB', and two as 'some concerns'. The certainty of evidence was very low.

CONCLUSIONS

The overall prevalence of postoperative pain after endodontic treatment using LC and HC of NaOCl was 45% and 39%, respectively.

CLINICAL RELEVANCE

Postoperative pain is common after endodontic treatment using NaOCl, but tends to decrease over time.

Comparative Evaluation of Different Irrigant Agitating Devices for Debris Removal from the Mesial Roots of Mandibular Molars: An In Vitro Study

AIM

To evaluate the efficiency of debris removal from the mesial root canals and isthmus of mesial roots of mandibular molars after final irrigant agitation with XP-endo Shaper, EndoVac (EV), plastic finishing file, and conventional needle irrigation.

METHODS AND MATERIALS

Forty extracted human mandibular first molar teeth with the isthmus between the mesial roots were selected, access cavities were prepared and distal roots were decoronated. All the mesial root specimens were mounted in acrylic, sectioned at the coronal, middle, and apical thirds, along with the resin block, and examined for debris in the canals and isthmus before the start of the procedure using a stereomicroscope and were mounted back in a custom-made jig. After determination of the working length, they were allocated to the following four different irrigant activation groups (n = 10): Group I-XP-endo Finisher; group II-EndoVac; group III-plastic finishing file; and group IV-standard needle irrigation. After biomechanical preparation (BMP) till F3, final agitation was done for debris removal with the respective agitating devices, and all the samples were examined under a stereomicroscope for the amount of debris in the canal after final agitation.

RESULTS

Of all the irrigation devices used, the XP-endo Finisher and EV showed more debris removal when compared to other groups (p < 0.05). The plastic finishing file in continuous rotation was more efficient in cleaning debris compared with conventional needle irrigation (p < 0.05).

CONCLUSION

The XP-endo Finisher and EV showed a significant difference in cleaning efficacy than the plastic finishing files. So, these can be used as adjunctive for agitating the final irrigant.

CLINICAL SIGNIFICANCE

The irrigant agitation devices promote the penetration of irrigants into the intricate root canal anatomy and increase their antibacterial and tissue-dissolving effectiveness thereby improving the success rate and treatment outcome.

A new model of in vitro dentin intratubular contamination for Fusobacterium nucleatum: Validation by confocal laser scanning microscopy

Objectives

To test and validate a new protocol for in vitro contamination of dentinal tubules using Fusobacterium nucleatum (F. nucleatum) by confocal laser scanning microscopy (CLSM), in addition to evaluating the effectiveness of conventional endodontic irrigants such as sodium hypochlorite (NaOCl) and chlorhexidine (CLX) on this biofilm.

Material and methods

Thirty lower premolars were contaminated with F. nucleatum (ATCC 51190) for 7 days under anaerobic conditions using the proposed new model. The specimens were divided into a control group and experimental groups, according to the irrigants: NaOCl 2.5% and CLX 2%. Then, the samples were submitted for analysis by CLSM and the LIVE/DEAD technique to quantify bacterial viability. Data normality was verified by the Shapiro-Wilk test. Intragroup and intergroup comparisons were performed using the Kruskal-Wallis test, followed by Dunn's post-test.

Results

The CLSM images obtained demonstrated the effectiveness of the proposed new contamination protocol, with a high percentage of viable bacteria in relation to the treated groups (p < 0.05). Lower viability values were observed for the 2.5% NaOCl group.

Conclusion

The new contamination protocol resulted in a high and homogeneous percentage of viable bacteria in the dentinal tubules in all specimens evaluated. Both irrigating solutions proved to be effective in reducing the intratubular microbiota, especially 2.5% NaOCl.

Endodontic Flare-Ups: An Update

Root canal treatment deals with mechanical and chemical cleaning followed by obturation that promotes healing and repair of periradicular tissues. Flare-ups can occur in between or some days after endodontic therapy leading to unscheduled visit by the patient. This complication is characterized by severe pain and/ or swelling. There is a correlation between number of appointments, intracanal medicament used and flare-ups. However, there is no sure procedure that can avoid this complication. Therefore, this review article has discussed about causes and some procedures to prevent and treat flare-ups.

Micro-CT analysis and leakage of bioceramic retrofillings after ultrasonic and Er:YAG laser cavity preparations: an in vitro study

The purpose of the study was to determine the influence of preparation techniques on marginal adaptation and sealing of Biodentine™ and TotalFill® RRM bioceramic retrograde fillings. Fifty-two single-root teeth extracted for periodontal reasons were used. Root canals were instrumented using Reciproc Blue #25 and obturated using a single cone technique with an AH Plus® root canal sealer. Retrograde cavities were prepared with Piezomed device (Piezo), Er:YAG laser in short-pulse(SP) and quantum square pulse(QSP) modes and filled with Biodentine™ (BD) or TotalFill® RRM (TF). There were 6 groups (n=8): (1) Piezo BD, (2) Piezo TF, (3) SP BD, (4) SP TF, (5) QSP BD, and (6) QSP TF, and positive and negative controls (n=2). Micro-CT analysis was performed on two samples from each group. Percentage volumes of internal and external voids in apical 1.5 mm were determined. Rhodamine B dye leakage was done on six samples. The samples were cut longitudinally and examined under a stereomicroscope. Digital recordings were analyzed in ImageJ software. The deepest penetration of color in mm was recorded. The data were statistically analyzed using ANOVA and Duncan's test at the level of significance α=0.05. TotalFill® RRM performed significantly better than Biodentine™ in terms of sealing (p<0.05) and marginal adaptation, as evaluated by micro-CT. Sealing was significantly better in SP compared to QSP mode preparations (p<0.05). Differences between Piezomed and laser modes were not significantly different (p>0.05). Sealing was statistically significantly better with TotalFill® RRM compared to Biodentine™ and in Er:YAG SP preparations compared to Er:YAG QSP.

Phytic Acid Demonstrates Rapid Antibiofilm Activity and Inhibits Biofilm Formation When Used as a Surface Conditioning Agent

Root canal infections are associated with biofilms and are treated with chemical irrigants with a high success rate. However, treatment failure does arise, which is attributed primarily to resistance exhibited by biofilms. Currently used irrigants in root canal treatment have disadvantages, and there is therefore a need for more biocompatible alternatives with antibiofilm properties to reduce root canal treatment failure and complications. The aim of this study was to evaluate the in vitro antibiofilm properties of phytic acid (IP6), which is a potential alternative treatment agent. Single- and dual-species biofilms of Enterococcus faecalis and Candida albicans were developed on the well surfaces of 12-well plates and on hydroxyapatite (HA) coupons, and then exposed to IP6. In addition, selected HA coupons were preconditioned with IP6 before biofilm development. IP6 demonstrated bactericidal effects and altered the metabolic activity of biofilm cells. Confocal laser-scanning microscopy showed that IP6 caused significant and rapid reduction in live biofilm cells. At sublethal concentrations, IP6 did not alter the expression of tested virulence genes except for C. albicans hwp1, the expression of which was upregulated but not reflected by a change in hyphal transformation. IP6-preconditioned HA coupons led to extensive inhibition of dual-species biofilm formation. The results of this study highlight for the first time the antibiofilm inhibitory properties of IP6 and the potential for its exploitation in several clinical applications. IMPORTANCE Root canal infections are biofilm associated, and despite mechanical and chemical treatment procedures, infection recurrence occurs, and this is likely due to the high tolerance of associated biofilms to antimicrobials. The currently used treatment agents have several disadvantages, which necessitates the search for new improved agents. In this study, the natural chemical phytic acid was found to exhibit antibiofilm activity against established mono and dual mature biofilms over a short contact time. Most importantly, phytic acid was found to cause significant inhibition of dual-species biofilm formation when used as a surface preconditioning agent. The findings of this study identified a novel use of phytic acid as a potential antibiofilm agent that can be used in several clinical applications.

Evaluating the Efficacy of Certain Intermediate Irrigants in Preventing Precipitate Formed Due to Sodium Hypochlorite and Chlorhexidine Within the Root Canal System: An In Vitro Study

AIM

Root canal irrigation using a mixture of sodium hypochlorite (NaOCL) and chlorhexidine gluconate (CHX) might cause a precipitate to develop. This study aims to check the efficacy of sodium thiosulfate and normal saline as irrigating solutions.

MATERIALS AND METHODS

Roots of 45 teeth were biomechanically prepared, and the teeth were then tested. A size 15k file was introduced to the point where the apical foramen could be visible in order to provide an accurate reading of the working length. As a precaution against irrigating solutions leaking out, the specimens' tips were sealed with modeling wax before being instrumented. Each group's root canals were instrumented with #F4 hand Protaper (Dentsply Sirona, USA) as recommended by the manufacturer. Between instrumentation, The canals were lubricated with ethylenediamine tetraacetic acid (EDTA) and irrigated with 2.5% sodium hypochlorite (RC Help, Prime Dental, Mumbai, India). Fifteen samples were randomly assigned to one of three experimental categories based on the middle watering arrangement used: Group 1 (control), Group 2 (saline irrigant), and Group 3 (3.86% sodium thiosulfate). The jewel plate was submerged in water to cool it down, while two longitudinal scores were made on the root's buccal and lingual surfaces. We used a stereomicroscope to examine the exposed surfaces of the root trench in the coronal, middle, and apical thirds for the orange-earthy colored material (Stereozoom Nikon magnifying lens under 20X amplification), and we used the Mann-Whitney U test and the Kruskal Wallis test during our thorough analysis.

RESULTS

The precipitation generated in the coronal, middle, and apical thirds had significantly different thicknesses. While precipitation did occur in all three regions, it was at a much lower rate in the apical third compared to the coronal and middle regions. In Group 1, the control group, the precipitate was thicker than in Groups 2 (saline irrigant) and 3 (3.86% sodium thiosulfate).

CONCLUSION

Sodium thiosulfate, which is a biocompatible solution, can be used as an intermediate irrigant as it shows less precipitate as compared to saline.

Analysis of Temperatures Generated during Conventional Laser Irradiation of Root Canals-A Finite Element Study

The success of endodontic treatment is dependent on the removal of bacteria. A modern strategy to reduce bacterial load is laser irradiation. During this procedure, there is a local increase in temperature with possible side effects. The aim of this study was to determine the thermal behavior of a maxillary first molar when performing the conventional irradiation technique using a diode laser. For this study, a 3D virtual model of a maxillary first molar was created. The preparation of the access cavity, the rotary instrumentation of the palatal root canal and the laser irradiation protocol were simulated. The model was exported in a finite element analysis program where the temperature and heat flux were studied. Temperature and heat flux maps were obtained, and the temperature increase on the internal wall of the root canal was analyzed. The maximum temperature value exceeded 400 °C and was maintained for less than 0.5 s. The obtained temperature maps support the bactericidal effect of diode laser and the limitation of damage to surrounding tissues. On internal root walls, the temperature reached several hundred degrees Celsius, but for very short durations. Conventional laser irradiation is an adjuvant method of decontamination of the endodontic system.

Effect of sodium/calcium hypochlorite on adhesion and adaptation of fiber posts luted with a dual resin cement

This study aimed to evaluate the effect of different concentrations of sodium hypochlorite (NaOCl) and calcium hypochlorite [Ca(OCl)2] on the bond strength and adaptation of glass fiber posts luted with a dual-curing resin cement. Fifty decoronated premolars were sectioned 14 mm from the apex and endodontically treated. The root canal filling was partially removed. The specimens were divided into 5 groups (n=10) according to the irrigant for post space irrigation: 0.9% sodium chloride (NaCl), (control); 2.5% NaOCl; 5.25% NaOCl; 2.5% Ca(OCl)2; and 5.25% Ca(OCl)2. For each group, irrigation was performed with 5 ml of solution. Afterward, the posts were luted with a dual-curing resin cement. One slice from each third was obtained and submitted to the push-out test and failure modes analysis. An additional slice from the middle third was submitted to confocal images for analysis of adaptation failures (gaps). Two-way ANOVA, Tukey's post-hoc, Kruskal-Wallis with Bonferroni adjusted, and chi-square tests, analyzed data. The group treated with 5.25% NaOCl showed lower bond strength values and generated more cohesive failures compared to the control (p < 0.05). Bond strength decreased from coronal to apical in the post space (p < 0.001). The groups treated with NaOCl had the highest percentages of gaps compared to the control (p < 0.05). Regardless of concentration, Ca(OCl)2 did not influence the bond strength and the occurrence of gaps (P > 0.05). Ca(OCl)2 is a good option for irrigating the post space before luting a fiber post with a dual-curing resin cement.

Effect of different disinfection protocols in bacterial viability of an intraradicular biofilm formed in situ

The present study aimed to evaluate bacterial viability after the use of different disinfection protocols in root canals infected with a multispecies biofilm (MB) formed in situ. Palatal roots with a single canal were obtained from extracted maxillary molars and sterilized before being inserted into the mouth. The roots were contaminated with a MB in an intraoral appliance worn by ten volunteers. All volunteers wore six roots simultaneously in two intraoral devices for 21 days. One root from each volunteer was assigned to each group (n=10): PUI - passive ultrasonic irrigation; EC - Easy Clean; XPF - XP-endo Finisher; aPDT - antimicrobial photodynamic therapy; CI - conventional irrigation; and NC - negative control. The samples were evaluated under confocal laser scanning microscopy. The percentage of viable cells (VC) was calculated over the total percentage of MB biovolume. Data were statistically analyzed (α=5%). The cell viability in the entire root canal or for each third was compared between groups (Kruskal-Wallis test, Dunn post-hoc test) and for the same group (Friedman test, Dunn post-hoc test). Disinfection protocols were not significantly different from each other (P>.05). Samples in EC, PUI, and aPDT had lower cell viability than in NC (P<.05). In the coronal third of samples in the EC, XPF, PUI and aPDT, the percentage of VC biovolume was lower than in the NC (P<.05). The percentage of VC in EC samples was lower in the coronal and middle thirds than in the apical third (P<.05). EC, PUI and aPDT had significant effects on cell viability in intraradicular multispecies biofilm formed in situ when compared with untreated samples.

Comparison of dentinal tubular penetration of Intra-canal heated and Pre-heated sodium hypochlorite through different agitation techniques

INTRODUCTION

The efficacy of sodium hypochlorite (NaOCl) as an intracanal irrigant is widely debated in endodontic therapy. This study aimed to analyze and compare the penetration abilities of different modes of NaOCl application and assess the impact of various agitation strategies on promoting root canal cleanliness.

MATERIALS AND METHODS

This study included 168 single-rooted mandibular premolars that were randomly divided into eight groups. The two modes of application of 5% NaOCl evaluated were intracanal heating and preheating, and the agitation strategies included ultrasonic, sonic, and manual dynamic agitations (MDAs). The samples were sectioned and observed at a magnification of 1000× under a scanning electron microscope.

RESULTS

The analysis of variance test showed a statistically significant difference among the various groups of agitation (P < 0.05). The post hoc Tukey test confirmed that preheated NaOCl with ultrasonic agitation, intracanal-heated NaOCl with sonic agitation, and MDA had significantly higher debris scores of 1, 4, and 5, respectively, in the apical third of the canal.

CONCLUSION

The results indicated that the combination of intracanal-heated NaOCl and ultrasonic agitation is an effective method for reducing debris in the root canal system. These findings highlight the importance of considering both the mode of application and the agitation strategies when optimizing the use of NaOCl as an intracanal irrigant in endodontic therapy.

Recent Advances in Apical Periodontitis Treatment: A Narrative Review

Apical periodontitis is an inflammatory response caused by pulp infection. It induces bone resorption in the apical and periapical regions of the tooth. The most conservative approach to treat this condition is nonsurgical endodontic treatment. However, clinical failure has been reported with this approach; thus, alternative procedures are required. This review highlights recent literature regarding advanced approaches for the treatment of apical periodontitis. Various therapies, including biological medications, antioxidants, specialized pro-resolving lipid mediators, and stem cell therapy, have been tested to increase the success rate of treatment for apical periodontitis. Some of these approaches remain in the in vivo phase of research, while others have just entered the translational research phase to validate clinical application. However, a detailed understanding of the molecular mechanisms that occur during development of the immunoinflammatory reaction in apical periodontitis remains unclear. The aim of this review was to summarize advanced approaches for the treatment of apical periodontitis. Further research can confirm the potential of these alternative nonsurgical endodontic treatment approaches.

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.