Exploring Periostracum as an Alternative Root Canal Irrigant: Insights From Zebrafish Embryo Experiments.

Objectives Root canal treatments aim to eliminate biofilms effectively. Considering the limitations of chemical irrigants, there is growing interest in natural alternatives like periostracum due to their antibacterial and fouling-resistant properties. This study aimed to assess periostracum's toxicity as a root canal irrigant by investigating its effects on zebrafish embryos' heart rate, survival rate, and hatching rate, as well as inflammation studies using neutral red assays comparing it to standard irrigants like ethylenediaminetetraacetic acid (EDTA), chlorhexidine (CHX), and sodium hypochlorite (NaOCl). Materials and methods Zebrafish embryos were exposed to varying concentrations of periostracum irrigant and standard irrigants. Heart rate, survival rate, and hatching rate were evaluated as indicators of developmental toxicity using microscopy. Statistical analysis, utilizing GraphPad Prism software (version 5.03, GraphPad Software, LLC, San Diego, California, United States), involved one-way ANOVA and Tukey's post-hoc test to determine significance levels (p < 0.05) across control and other groups based on triplicate means and standard deviation. Results The periostracum irrigant demonstrated superior survival rates, heart rates, and hatching rates at specific concentrations compared to standard irrigants (p < 0.01), maintaining favorable heart rates and hatching rates at those concentrations. However, higher concentrations resulted in diminished hatching rates (p < 0.05). Additionally, this study revealed increased inflammation when larvae were treated with NaOCl, EDTA, and CHX. Conversely, no inflammation was observed when subjected to periostracum irrigants. These findings suggest potential advantages of periostracum as a root canal irrigant due to its increased biocompatibility. Conclusion Periostracum displayed promising attributes in zebrafish embryo experiments, such as stable heart rate, hatching rate, and survival rate, along with reduced developmental toxicity and inflammation, indicating potential advantages as a root canal irrigant, including reduced toxicity compared to conventional agents. Further research involving diverse demographics and long-term effects is crucial to validate periostracum's clinical applicability and safety in endodontic therapies.

Engineering a Microphysiological Model for Regenerative Endodontic Studies.

Dental pulp infections are common buccal diseases. When this happens, endodontic treatments are needed to disinfect and prepare the root canal for subsequent procedures. However, the lack of suitable in vitro models representing the anatomy of an immature root canal hinders research on regenerative events crucial in endodontics, such as regenerative procedures. This study aimed to develop a 3D microphysiological system (MPS) to mimic an immature root canal and assess the cytotoxicity of various irrigating solutions on stem cells. Utilizing the Dental Stem Cells SV40 (DSCS) cell line derived from human apical papilla stem cells, we analyzed the effects of different irrigants, including etidronic acid. The results indicated that irrigating solutions diminished cell viability in 2D cultures and influenced cell adhesion within the microphysiological device. Notably, in our 3D studies in the MPS, 17% EDTA and 9% 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) irrigating solutions demonstrated superior outcomes in terms of DSCS viability and adherence compared to the control. This study highlights the utility of the developed MPS for translational studies in root canal treatments and suggests comparable efficacy between 9% HEBP and 17% EDTA irrigating solutions, offering potential alternatives for clinical applications.

Influence of Passive Ultrasonic Irrigation of the Photosensitizer Used in Photodynamic Therapy on Microbial Reduction in the Root Canal System: An in Vitro Study.

Introduction: The success of endodontic treatment is based on microbial reduction promoted by the interaction of chemical and mechanical procedures. Photodynamic therapy (PDT) is used as an adjunct to conventional treatment, with significant microbial reduction. This study aimed to evaluate the influence of passive ultrasonic irrigation (PUI) of the photosensitizer (PS) used in PDT on microbial reduction in the root canal system. Materials and Methods: Forty-five mesiobuccal root canals from extracted human mandibular molars that were inoculated with standard strains of Enterococcus faecalis, Candida albicans, and Streptococcus mutans for 21 days were selected. The root canals were prepared using the ProTaper Next system and randomly divided into 3 groups (n=15): 1) PDT: PDT alone; 2) PUI+PDT: PUI followed by PDT; and 3) PUI/PS+PDT: PUI of the PS followed by PDT. Microbiological samples were collected from the canals before and after using the protocols described above. The data were analyzed by analysis of variance (Tukey's test) at a significance level of 5%. Results: Microbial counts before PDT, PUI+PDT, and PUI/PS+PDT did not differ significantly (P>0.05), showing methodological standardization in the microbial contamination of the root canal system. There was a significant reduction in microbial counts after PDT (61.05%), PUI+PDT (65.04%), and PUI/PS+PDT (68.58%) (P<0.01), but with no statistically significant difference between the three groups (P>0.05). Conclusion: Based on the present findings, it was concluded that the combination of PUI with PDT or PS activation did not influence microbial reduction achieved by PDT alone.

The Effect of Different Compositions and Concentrations of Etidronate-Containing Irrigants on the Antibacterial Activity of Sodium Hypochlorite against Enterococcus faecalis and Candida albicans.

We assessed the effect of different compositions and concentrations of two etidronate-containing irrigants on the antibacterial activity of sodium hypochlorite (SH) against Enterococcus faecalis and Candida albicans in vitro. Pure cultures of C. albicans and E. faecalis were isolated from root canal samples. The disc diffusion method was used to compare the antibacterial effect of pure SH and SH mixed with 9%, 15%, and 18% etidronate of two manufactures (dual rinse (DR); IsraDent (ID)) and EDTA. The pH and temperature of the solutions were measured immediately after mixing and within 40 min. The ANOVA revealed a significant influence of the type of irrigating solution on the C. albicans and E. faecalis inhibition zone diameters that ranged from 6.6 to 51.6 mm and from 6.4 to 12.4 mm, respectively. SH with DR 9% exhibited the highest effect against C. albicans. The antifungal activity of the other irrigants was SH = SH + DR15% = SH + DR18% = SH + ID9% > SH + EDTA > SH + ID15% > SH + ID18%. No significant differences in the anti-E. faecalis effect were revealed between the tested solutions except for the mixtures of SH and 15% and 18% ID, which exhibited no antiseptic effect. There was a strong positive correlation between antiseptic activity against both microorganisms and the pH values of the tested solutions. In conclusion, most etidronate formulations did not significantly hamper sodium hypochlorite activity against C. albicans and E. faecalis. The effect was concentration- and manufacturer-dependent.

Effects of Sodium Hypochlorite Concentration and Application Time on Bacteria in an Ex Vivo Polymicrobial Biofilm Model.

INTRODUCTION: In endodontic treatment, it is important to remove or inactivate biofilms in the root canal system. We investigated the effects of different concentrations and application times of sodium hypochlorite (NaOCl) on the viability of bacteria in ex vivo polymicrobial biofilms of different maturation levels. METHODS: Polymicrobial biofilms were prepared from dental plaque samples and grown for 1, 2, and 3 weeks under anaerobic conditions on collagen-coated hydroxyapatite discs as an ex vivo biofilm model. The biofilms were then exposed to NaOCl at concentrations ranging from 0.1% to 2% for 1 or 3 minutes. The control group was exposed to sterile distilled water. Viability staining was performed and examined by confocal laser scanning microscopy to determine the percentage of biofilm bacteria killed by NaOCl. Scanning electron microscopy was also performed to visually examine the biofilms. RESULTS: Application of NaOCl at 0.5%-2% for both 1 and 3 min killed significantly more bacteria when compared to the controls (P < .05). Cell viability tended to be lower after the application of NaOCl for 3 minutes than that for 1 minute. CONCLUSIONS: Our experiments using an ex vivo model showed that within the range of 0.1%-2% of NaOCl, higher NaOCl concentrations and longer application times were more effective in killing biofilm bacteria, and that mature biofilms were more resistant to NaOCl than younger biofilms.

Adhesion and sealing of different universal adhesive systems associated with bulk-fill resins after using endodontic irrigation solutions: An in vitro study.

This study aimed to evaluate the interface of universal adhesive (UA) with bulk-fill resin (BF) and dentin, after endodontic irrigation. The pulp chamber of 96 molars was irrigated with chlorhexidine 2% (CHX) or sodium hypochlorite 5.25% (NaOCl) and restored according to three restorative protocols. Microtensile bond strength (µTBS) and nanoleakage tests were performed after 24 h of thermocycling. Kruskal Wallis, Mann-Whitney and Wilcoxon were performed (p < 0.05). Comparing restorative systems, a difference was found only when irrigated with CHX after 24 h. CHX provided higher µTBS than NaOCl after 24 h for two restorative protocols; after thermocycling, NaOCl provided the greatest µTBS than CHX for one group. Decreased µTBS was observed for all restorative systems when CHX was used after thermocycling. NaOCl demonstrated the highest nanoleakage. The composition of UA influenced the immediate adhesion and sealing to BF when CHX was used; ageing has a deteriorating effect on adhesion and sealing for all restorative systems.

Comparation of the effectiveness of conventional needle irrigation and photon-induced photoacoustic streaming with sodium hypochorite in the treatment of teeth with apical periodontitis: a randomized clinical trial.

Photon-initiated photoacoustic streaming (PIPS) with an Er: YAG laser has been introduced in root canal treatment to improve irrigation and facilitate the removal of bacteria in the root canal system. This study aimed to compare the antibacterial effectiveness of two different root canal irrigation techniques, conventional needle irrigation (CNI) and PIPS, using 1% sodium hypochlorite (NaOCl), in the treatment of teeth with apical periodontitis. Sixty patients with a total of sixty teeth affected by apical periodontitis were included in this study. The teeth underwent root canal therapy, and after mechanical instrumentation, they were randomly assigned to two groups (n = 30) based on the final irrigation protocol: CNI or PIPS with 1% NaOCl. Bacterial suspensions in the root canals were evaluated using Adenosine 5'-triphosphate (ATP) assay kit after mechanical instrumentation and after final irrigation. Then, a follow-up was conducted after 7 days. The results revealed that final irrigation significantly reduced ATP values in both the CNI and PIPS groups (P < 0.001). The ATP values after final irrigation was greater in the CNI group compared to the PIPS group (P < 0.001). After a 7-day follow-up, percussion tenderness and fistula were significantly resolved in both groups (P < 0.05). A multivariate linear regression model was used to identify the factors that influence post irrigation ATP values. The analysis demonstrated that pre-operative percussion tenderness (P = 0.006), the presence of a fistula (P < 0.001) and the method used in the final irrigation (P < 0.001) had a significant impact on the ATP value after final irrigation. These results indicate that employing PIPS with 1% NaOCl as the final irrigation protocol exhibited superior antibacterial effectiveness and has the potential to enhance clinical outcomes in the treatment of teeth afflicted with apical periodontitis.

Extrusão apical de irrigantes em dentes imaturos utilizando diferentes dispositivos de irrigação por pressão negativa / Apical extrusion of irrigants in immature teeth using different negative pressure irrigation devices

Objetivo: O objetivo deste estudo foi avaliar a extrusão apical de irrigantes em dentes imaturos simulados, comparando a irrigação convencional com outros dispositivos de irrigação por pressão negativa. Materiais e Métodos: 48 amostras de dentes imaturos simulados foram montadas em um modelo adaptado para conter o irrigante extravasado e distribuídas igualmente em 4 grupos (n=12) de acordo com o dispositivo de irrigação utilizado: Grupo Irrigação Convencional (IC), Grupo EndoVac (EV), Grupo Pulp Sucker (PS) e Grupo Ivac (IV). As amostras foram irrigadas com 15mL de solução irrigadora, sendo 10mL de NaOCl a 2,5% e 5mL de EDTA a 17% intercalados. As amostras foram pesadas em balança de precisão antes e depois dos procedimentos de irrigação, sendo a diferença entre os pesos final e inicial considerado o volume de irrigante extravasado. Os dados foram coletados e analisados estatisticamente pelos testes de Kruskal-wallis e exato de Fisher. Resultados: Os grupos que utilizaram pressão negativa promoveram significativamente menor volume de irrigante extravasado que o grupo IC (p<0,05), não havendo diferenças significativas quando comparados entre si (p>0,05). Houve diferenças significativas na associação entre os grupos e a extrusão de irrigante, sendo o grupo PS menos associado a extrusão de irrigante (p<0,005). Discussão: Estudos anteriores apontam os dispositivos de pressão negativa como opções seguras diante de extravasamento de irrigantes quando comparados à irrigação convencional. Conclusão: A irrigação convencional promoveu significativamente maior volume de extrusão de irrigante quando comparada aos dispositivos de irrigação por pressão negativa. O sistema PulpSucker mostrou extravasamento de irrigante em um número significativamente menor de amostras.

Aim: The aim of this study was to evaluate the apical extrusion of irrigants in simulated immature teeh, comparing convencional irrigation with other negative pressure irrigation devices. Materials and methods: 48 samples of simulated immature teeth were set up in an adapted model to contain the extravasated irrigant and evenly distributed into 4 groups (n=12) according to the device used: Convencional Irrigation Group (CI), EndoVac Group (EV), Pulp Sucker Group (PS) and Ivac Group (IV). The samples were irrigated with 15mL of irrigant solution, consisting of 10mL NaOCl 2,5% and 5mL EDTA 17%, in na alternating sequence. The samples' weights were measured using a precision scale before and after the irrigation procedures, with the difference between de final and initial weights considered the volume of extravasated irrigant. Data were collected and statistically analyzed by Kruskal-wallis and Fisher exact tests. Results: The groups that used negative pressure devices significantly promoted a lower volume of extruded irrigant than the CI group (p<0,05), with no significant differences between the negative pressure groups (p>0,05). There were signficant differences in the association between the groups and irrigant extrusion, with the PS group showing significantly less association with irrigant extrusion (p<0,005). Discussion: Previous studies have indicated that negative pressure devices are safe alternatives to convencional irrigation when considering irrigant extrusion. Conclusion: Conventional irrigation promoted a significantly greater volume of irrigant extrusion when compared to negative pressure irrigation devices. The PulpSucker system showed irrigant extravasation in significantly fewer samples.

Clinical, Histological, and Molecular Perspective on Regenerating Nonvital Immature Teeth.

Background: Disinfection and dentin conditioning promote a favorable scenario for regenerative endodontic treatment. Clinical reports have confirmed periapical normality with high variability in disinfection protocols; nevertheless, the nature of neoformed tissue varied between them. Thus, this study aimed to present the impact of disinfection protocols on the clinical, histological, and molecular outcomes of regenerative endodontics procedures in permanent teeth with incomplete root formation. Materials and Methods: Eighteen teeth with incomplete root formation which required endodontic regenerative treatment were treated with different disinfection and conditioning agents and followed under clinical control. One case was evaluated under histological and immunohistochemical analyses. Results: Clinical outcomes revealed periapical repair in 17/18 cases. Histological and immunohistochemical analyses confirmed the neoformation of the dentinal matrix and its mineralization. Conclusions: Chemical conditioning could impact the outcome of regenerative endodontic procedures. The histological and immunohistochemical analysis showed the nature of the newly formed tissue that correlates with the clinical outcome.

Development of a High Penetration Safe Irrigant from Withania somnifera.

Background: Herbal medicine is regaining a strong position in health care by virtue of better safety and minimal toxicity as compared to conventional chemotherapies. It is making a place in dental care in the form of various toothpastes, lotions, and mouthwashes. It has been analyzed that very few discrete herbal irrigants have an action comparable to that of sodium hypochlorite. No data about any study on penetration depth and penetration area for herbal-based irrigants used in root canal treatment are available. Aim: The aim of this study was to assess the efficacy of Withania somnifera extracts by assessing its penetration depth and area inside dentinal tubules using a confocal laser scanning microscope. Materials and Methods: Freshly extracted 25 maxillary central incisors were divided into three groups: Group 1: W. somnifera; Group 2: sodium hypochlorite; and Group 3: distilled water. Results: W. somnifera showed better results with respect to penetration depth and area inside the dentinal tubules thansodium hypochlorite. Conclusion: From the study, it can be concluded that W. somnifera extract-based irrigant may be used as an alternative to sodium hypochlorite-based irrigant. It also shows that more herbal drugs need such types of screening and incorporation in dental practice to reduce the potential side effects of the conventional drugs used in daily practice.

Efficacy of Different Root Canal Irrigating Solutions in Removing Smear Layer: A Scanning Electron Microscopic Study.

Background The aim of the present investigation was to evaluate and compare the efficacy of frequently used chemical agents in terms of their capacity to eliminate the smear layer after instrumentation, as observed via scanning electron microscopy (SEM). Materials and methods Sixty extracted single-rooted mandibular premolar teeth, each with roots 15 mm in length, were used in this study. The teeth were divided into one control group and four study groups, each containing 12 teeth. In Control Group 0, teeth were irrigated with 3 ml of saline only. In Group 1, teeth were irrigated initially with 3% sodium hypochlorite (NaOCl) and then given a final rinse with 3 ml of 17% ethylenediaminetetraacetic acid (EDTA) for one minute. In Group 2, teeth were irrigated with 3% NaOCl and given a final rinse with 3 ml of a mixture of tetracycline, acid, and detergent (MTAD, BIOPURE) for one minute. In Group 3, teeth were irrigated with saline and given a final rinse with 3 ml of 17% EDTA for one minute. In Group 4, teeth were irrigated with saline and given a final rinse with 3 ml of MTAD for one minute. One-half of each tooth was chosen and prepared for scanning electron microscopic (SEM) examination at the cervical, middle, and apical thirds. These were observed at magnifications of up to 1,000 times to check for the presence or absence of a smear layer. The data were analyzed using the Kruskal-Wallis test and post-hoc Dunn's test. Results All of the root canal irrigation protocols exhibited superior efficacy compared to the control group in the elimination of the smear layer. Group 2 (3% NaOCl with MTAD) showed the lowest mean scores, compared to all the groups, followed by Group 1 (3% NaOCl with 17% EDTA). MTAD was more effective than EDTA. The smear layer was effectively removed from the apical third, followed by the middle and coronal thirds of the root. Conclusion Initial irrigation with 3% NaOCl and one-minute final irrigation with 3 ml MTAD was the most effective root irrigant, and particularly indicated in teeth with infection of the apical third.

Antimicrobial Efficacy of a Novel Automated Irrigation Device As Compared to Conventional Needle Irrigation Against Enterococcus faecalis: An In Vitro Study.

Aim The present study aims to compare the antibacterial efficacy of a novel automated endodontic irrigation device with that of a manual irrigation technique. Materials and methods The present study considered 45 extracted single-rooted teeth. After sectioning the teeth, the specimens were inoculated with Enterococcus faecalis (E. faecalis) bacteria for three weeks. Instrumentation was done using ProTaper Gold rotary files to size 50 and 5% taper. Based on the irrigation protocol, the experimental samples were divided into Group I: control (normal saline irrigation) (n = 15); Group II: conventional needle irrigation (n = 15); and Group III: automated irrigation (n = 15). The irrigation in Group III was done using the automated irrigation device. After the experimental irrigation, the pre-weighted dentinal shaving was collected in Eppendorf tubes, diluted 10 times, and incubated in the Petri dish with tryptone soy agar (TSA) for 48 hours. Finally, the colony-forming unit (CFU) counts were assessed. IBM SPSS Statistics for Windows version 23.0 (Armonk, NY, USA, IBM Corp.) was used for data analysis. Intergroup comparisons were made using the non-parametric Kruskal-Wallis test. Results The mean CFU count (CFU/ml) for the groups was: Group 1 (normal saline irrigation): 3.67x101; Group 2 (manual irrigation): 2.69× 101; Group 3 (automated irrigation): 1.57× 101. A statistically significant reduction in E. faecalis CFU count was seen among the groups assessed (p<0.01). The automated irrigation group exhibited the most substantial reduction in E. faecalis CFU count. Group 2 showed a significant difference compared to Group 1 (p<0.05). Conclusions The novel automated endodontic irrigation device was superior to manual irrigation in reducing E. faecalis CFU counts. This indicates that the automated irrigation device has the potential to enhance bacterial elimination efficacy during endodontic treatment.

Effect of active irrigation using shock wave-enhanced emission photoacoustic streaming on dental pulp stem cell viability.

Background: Shock wave-enhanced emission photoacoustic streaming (SWEEPS) is a novel irrigation activation method based on photoacoustic streaming. The aim of this study was to look into the impact of SWEEPS on the attachment and survival of dental pulp stem cells (DPSCs). Materials and Methods: In this in vitro study, 34 standardized root segments were randomly allocated into two groups: SWEEPS and the conventional conditioning group. After the irrigation, human DPSCs were seeded on the internal walls of these samples, and the attachment and survival of 30 of them were assessed on different days. The remaining two samples were observed using a scanning electron microscope (SEM). Independent sample t-test, Mann-Whitney U-test, one-way ANOVA, Kruskal-Wallis, and two-way ANOVA were used for data analysis with the level of significance = 0.05. Results: The viability of DPSCs was significantly greater in the SWEEPS group in comparison with the conventional conditioning group (P = 0.029). Both groups have shown a significant increase in the viability of DPSCs over time (P = 0.0001, P = 0.003). SEM results have shown a smear layer-free surface with firmly attached DPSCs in the SWEEPS group. Conclusion: The results of this study indicated that active irrigation using SWEEPS could provide a superior surface in terms of viability and attachment of DPSCs compared to the conventional conditioning method.

Effect of irrigation protocols on smear layer removal, bond strength and nanoleakage of fiber posts using a self-adhesive resin cement.

Objectives: This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods: Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)-2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX- and 3 groups with 2% CHX irrigation/activation-by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey's test (α = 0.05). Results: For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions: Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

Influence of sodium hypochlorite on cyclic fatigue resistance of nickel-titanium instruments: A systematic review and meta-analysis of in vitro studies.

OBJECTIVE: This systematic review/meta-analysis investigated the influence of NaOCl on cyclic fatigue resistance of endodontic NiTi instruments. MATERIALS AND METHODS: A systematic search until July 2022 in PubMed/MEDLINE, Embase, Scopus, Web of Science, SciELO, Cochrane Library, and grey literature was conducted. According to the PECOS strategy, only in vitro studies evaluating the effects of NaOCl on the cyclic fatigue resistance of NiTi instruments were eligible. Cyclic fatigue resistance was the primary outcome. A modified Joanna Briggs Institute's Checklist was used for risk of bias assessment. RESULTS: Of the 2,445 records screened, 37 studies were included. Most studies used simulated canals made of stainless-steel block with severe to moderate curvatures. NaOCl concentration varied from 1-6%, mainly at 37 °C. Regarding fatigue resistance, 23 studies using 1.2% to 6% NaOCl showed a reduction in the resistance compared to the control groups, especially when pre-heated. Four meta-analyses were performed according to the tested NiTi systems. The meta-analyses indicated that the PTU F2 files had higher reduction of fatigue resistance after exposure to 5.25% NaOCl; no differences between NaOCl and no immersion were observed for Reciproc R25, WaveOne 25.08, and WaveOne Gold Primary files. Included studies had low risk of bias. CONCLUSION: NaOCl appears to reduce cyclic fatigue resistance of certain NiTi files, especially when they are pre-heated, particularly in conventional NiTi files compared to some heat-treated instruments. It is possible that the temperature of the solution may have a greater influence on resistance than NaOCl itself. Important to note that an overall tendency toward no significant influence was observed among various systems. CLINICAL RELEVANCE: Precautions are necessary when a pre-heated high-concentration NaOCl is used to enhance its properties during root canal preparation, mainly using conventional wire.

Comparative Evaluation of Effectiveness of Nisin, Amoxicillin/Clavulanic Acid (Augmentin) and Chlorhexidine on E. Faecalis as an Intracanal Irrigant: An In-vitro Study.

Aim: The present study evaluated the antimicrobial efficacy of chlorhexidine gluconate (CHX), Nisin, and Amoxicillin/Clavulanic Acid (Augmentin) as an intracanal irrigant against Enterococcus faecalis (EF). Materials and Methods: Minimum Inhibitory Concentration (MIC) for EF against Nisin and Augmentin was determined by microbroth dilution technique. Time kill cycle (TKC) analysis was done for 0 MIC, ½ MIC, 1 MIC, and 2 MIC at 0 hour, 15 minutes, 30 minutes, and 45 minutes. At the end of each time period, dilutions were pipetted and swabs of agar plates were done. Incubation of agar plates was done at 37C for 24 hours. Colonies formed were counted. Results: The time kill curve analysis of EF for CHX, Nisin, and Augmentin at different concentrations and time periods showed a gradual decline in mean bacterial count between 0 and 45 minutes for CHX; this decline increases with increase in concentrations and time. Whereas in group Nisin, not much decline in bacterial count is noted for ½ MIC concentrations but a signification reduction of P < 0.001 after exposure to Nisin at 1 MIC ant 2 MIC concentrations. Group Augmentin showed not much reduction in bacterial count with increase in concentration and time. Conclusion: From this study, Nisin is found to be a promising agent in eliminating EF in comparison to other irrigants tested. However, the systemic effect of this irrigant, its biocompatibility, allergic potential, and bacterial resistance needs further investigation.

Comparative Evaluation of Intracanal Smear Layer Removal by Different Root Canal Irrigants: A Scanning Electron Microscope Study.

Aim: The purpose of the study is to compare and evaluate the efficacy of different root canal irrigants-100, 75, 50, and 25% neem extract, 100, 75, 50, and 25% apple cider vinegar (ACV), a combination of 5.25% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA), and saline on smear layer removal using a scanning electron microscope (SEM). Materials and methods: A total of 80 freshly extracted single-rooted teeth were collected and divided into 10 groups-group I: normal saline (negative control), group II: NaOCl with EDTA (positive control), group III: 100% neem extract, group IV: 75% neem extract, group V: 50% neem extract, group VI: 25% neem extract, group VII: 100% ACV, group VIII: 75% ACV, group IX: 50% ACV, and group X: 25% ACV. The samples were irrigated with a specific group of irrigants, then split in a longitudinal axis and processed for analysis in an SEM. Microphotographs were obtained and scored according to Torabinejad et al. Results: Microphotographs were assessed and showed that 100% neem extract was similar to NaOCl with EDTA, followed by 75% neem extract and 100% ACV. Conclusion: This study showed that 100% neem extract removed the smear layer, similar to the NaOCl with EDTA. How to cite this article: Sudhakar S, Gupta N, Ghambir N, et al. Comparative Evaluation of Intracanal Smear Layer Removal by Different Root Canal Irrigants: A Scanning Electron Microscope Study. Int J Clin Pediatr Dent 2023;16(4):633-638.

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.

The effect of nanobased irrigants on the root canal dentin microhardness: an ex-vivo study.

BACKGROUND: Given the favorable antimicrobial properties of zinc oxide (ZnONPs), standard silver (AgNPs), and imidazolium-based silver (Im-AgNPs) nanoparticles, this study aimed to evaluate their influence on the microhardness of root canal dentin. METHODS: In this experimental study, 40 mandibular premolars were decoronated at the cementoenamel junction and longitudinally sectioned into halves to create 80 specimens. They were randomly allocated to 5 groups (n = 16) and irrigated with ZnONPs, AgNPs, Im-AgNPs, NaOCl, or normal saline (as the negative control) for 15 min. The Vickers Hardness Number (VHN) was measured on each root canal third before and after being soaked in irrigants. Statistical analysis was performed using paired t-test, one-way ANOVA, and post hoc Tukey's test (α = 0.05). RESULTS: Im-AgNPs and ZnONPs irrigants improved the microhardness of root dentin, whereas, AgNPs and NaOCl decreased it. ZnONPs yielded the highest VHN at the coronal third (P˂0.001), while the Im-AgNPs provided the highest VHN at the middle and apical thirds (P˂0.001). The AgNPs group showed the lowest VHN at the apical third. CONCLUSIONS: The irrigants containing Im-AgNPs and ZnONPs significantly enhanced the root dentin microhardness. However, the use of AgNPs resulted in decreased microhardness.

In vitro assessment of antimicrobial potential of low molecular weight chitosan and its ability to mechanically reinforce and control endogenous proteolytic activity of dentine.

AIMS: Chitosan-based biomaterials exhibit several properties of biological interest for endodontic treatment. Herein, a low molecular weight chitosan (CH) solution was tested for its antimicrobial activity against Enterococcus faecalis (E. faecalis) and effects on dentine structure. METHODOLOGY: The root canal of 27 extracted uniradicular teeth were biomechanically prepared, inoculated with a suspension of E. faecalis and randomly assigned to be irrigated with either 5.25% sodium hypochlorite (NaClO), 0.2% CH or sterile ultrapure water (W). Bacteriologic samples were collected from root canals and quantified for of E. faecalis colony-forming units (CFUs). The effectiveness of CH over E. faecalis biofilms was further measured using the MBEC Assay®. Additionally, dentine beams and dentine powder were obtained, respectively, from crowns and roots of 20 extracted third molars. Dentine samples were treated or not with 17% EDTA and immersed in either CH or W for 1 min. The effects of CH on dentine structure were evaluated by assessment of the modulus of elasticity, endogenous proteolytic activity and biochemical modifications. RESULTS: The number of E. faecalis CFUs was significantly lower for samples irrigated with CH and NaClO. No significant differences were found between CH and NaClO treatments. Higher modulus of elasticity and lower proteolytic activity were reported for dentine CH-treated specimens. Chemical interaction between CH and dentine was observed for samples treated or not with EDTA. CONCLUSIONS: Present findings suggest that CH could be used as an irrigant during root canal treatment with the triple benefit of reducing bacterial activity, mechanically reinforcing dentine and inhibiting dentine proteolytic activity.