Comparative Evaluation of Nano Inorganic Metal Oxides as Intracanal Medicaments for Cytotoxicity and Antimicrobial Activity in the Root Canal System.

Aim and objective: To evaluate and compare the cytotoxicity and antimicrobial activity of various inorganic metal oxide nanoparticles along with vehicles when used as intracanal medicaments in the root canal system. Materials and methods: The study included triplicates (n = 36 times) that were subjected to n calcium oxide (CaO), n zinc oxide (ZnO), n magnesium oxide (MgO), and metapaste as intracanal medicaments. The efficacy of novel intracanal medicaments was evaluated for biocompatibility assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reagent following antimicrobial efficacy against Enterococcus faecalis (E. faecalis) was evaluated using zone of inhibition (ZOI) and minimum inhibitory concentration (MIC). The statistical analysis Kruskal-Wallis test, student t-test, and analysis of variance (ANOVA) using Statistical Package for the Social Sciences (SPSS) software (v.20.0). Results: The order of proliferative activity of experimental groups on L929 mouse fibroblast cells using MTT assay was: metapaste > nCaO > nMgO > nZnO). After evaluation of antimicrobial efficacy, group I: nCaO showed maximum ZOI and MIC against E. faecalis, which showed high statistically significant differences between all four groups after ANOVA (p < 0.0001*). Conclusion: n calcium oxide (CaO) mixed with propylene glycol (PPG) 400 has a potential role as an intracanal medicament with minimum cytotoxic effect and maximum antimicrobial activity against endodontic pathogens. Clinical significance: Nanoparticles-based intracanal medicament can provide a promising future in reducing endodontic flareups when used as intracanal medicament. How to cite this article: Barge P, Gugawad S, Devendrappa SN, et al. Comparative Evaluation of Nano Inorganic Metal Oxides as Intracanal Medicaments for Cytotoxicity and Antimicrobial Activity in the Root Canal System. Int J Clin Pediatr Dent 2023;16(S-2):S168-S175.

Antimicrobial Efficacy of Liquorice Extracts on Most Common Endodontics Pathogens.

Aim: The purpose of this study is to evaluate the Antimicrobial effect of liquorice extracts and compare its action to commonly used root canal medicaments like calcium hydroxide and chlorhexidine against Enterococcus faecalis and Candida albicans. Materials and Methods: Ethanolic and aqueous extracts of liquorice root were prepared. Antimicrobial activity was tested by agar well diffusion method on E. faecalis and C. albicans using Mueller Hinton agar. Wells were prepared and filled with ethanolic extract, aqueous extract of liquorice, calcium hydroxide, and chlorhexidine. Samples were incubated at 37°C, zone of inhibition was examined after 24 h. Results and Statistical Analysis: Ethanolic extract was significantly better (P < 0.001) than calcium hydroxide and aqueous extract of liquorice and less effective than chlorhexidine against E.faecalis. In C. albicans, ethanolic extract was less significant (P < 0.001) when compared to calcium hydroxide and chlorhexidine. Conclusion and Clinical Relevance: Ethanolic extract of liquorice has potent bactericidal effect against E. faecalis and C. albicans over aqueous extract. Hence, it can be used as intracanal medicaments in routine endodontic therapy.

Direct and residual antimicrobial effect of 2% chlorhexidine gel, double antibiotic paste and chitosan- chlorhexidine nanoparticles as intracanal medicaments against Enterococcus faecalis and Candida albicans in primary molars: an in-vitro study.

BACKGROUND: Thorough disinfection of root canals in primary molars may be complicated by the complex root canal morphology. This in-vitro study aimed to compare direct and residual antimicrobial effect of 2% chlorhexidine (CHX) gel, 500 mg/ml double antibiotic paste (DAP) and chitosan-chlorhexidine nanoparticles (CS-CHX NPs) as intracanal medicaments against Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) in primary molars. METHODS: Mesial roots of 63 mandibular second primary molars were infected with E. faecalis and C. albicans. Teeth were divided into 9 groups: Ia: (CS-CHX NPs), IIa: (CHX), IIIa: (DAP), IVa: chitosan nanoparticles (CSNPs) in which medicaments were placed for 3 days, groups Ib: (CS-CHX NPs), IIb: CHX, IIIb: (DAP), IVb: (CSNPs) in which medicaments were placed for 7 days, and Group V (control): teeth were infected, irrigated with saline, and sampled 3- and 7-days post-infection. Microbiological samples were obtained after infection, 3, and 7 days after medicament placement and 7 days after medicament removal for both time points. One-way ANOVA, Tukey's post hoc test and paired t-test were used at p < 0.05. RESULTS: CS-CHX NPs had the highest anticandidal effect which was comparable to CHX and significantly higher than other medicaments (p < 0.001) at both time points. CS-CHX NPs had the highest effect against E. faecalis which was comparable to DAP and significantly higher than other medicaments (p < 0.001) at 3 days. All medicaments showed similar effect against E. faecalis after 7 days. The 7-days placement significantly increased the antimicrobial effect against both micro-organisms in all groups, except CS-CHX NPs which showed an insignificant increase. CS-CHX NPs showed the highest residual effect against both micro-organisms that increased with 7-days placement. CONCLUSION: CSNPs and CHX combination showed a synergistic effect against both micro-organisms. CS-CHX NPs displayed a higher effect at a shorter period compared to other medicaments, yet its residual effect was higher with 7-days placement.

A Scoping Review of Highly Cited Published Articles in the Iranian Endodontic Journal: A Reflection of Trends in Endodontic Research.

Introduction: Highly cited published articles play a critical role in shaping clinical practice, research directions, and advancements in a specific field of science. The current comprehensive scoping review aimed to provide an overview of highly cited articles published in the "Iranian Endodontic Journal" (IEJ), based on the IEJ's H-index (=29); highlighting their key findings and prominent implications in the field of endodontics. Materials and Methods: A systematic search was conducted in Scopus database to identify the top 29 highly cited published articles. The articles were selected based on their citation count (h-index); reflecting their impact and influence within the scientific community. Data extraction was performed to gather relevant information; including authors, titles, publication years, and the main topic(s) of each article. Results: The selected highly cited published articles covered a broad range of endodontic topics; demonstrating the diversity and depth of research in the field. Key findings include significant contributions in vital pulp therapy, antimicrobial agents, root canal disinfection, regenerative techniques, cone-beam computed tomography applications, and intracanal medicaments. The distribution of research areas reflects the importance of evidence-based practice in clinical decision-making and patient care. Conclusions: These highly cited published articles have shown to have substantial impact on the field of endodontics. They have influenced clinical practice, guided research directions, and have improved patient care. The summary of key findings from each topic and the number of articles related to each area can provide readers with valuable insights into the distribution of research areas, and the significance of contributions made by the aforementioned highly cited published articles.

Feasibility of the crude extracts of Amorphophallus paeoniifolius and Colocasia esculenta as intracanal medicaments in endodontic therapy in comparison to the 940 nm diode laser: An in vitro antimicrobial study.

Background/purpose: The elimination and debridement of intracanal bacteria are credited with long-term effectiveness in endodontic therapy. This study aimed to compare the antimicrobial efficacies of Amorphophallus paeoniifolius (Suran), Colocasia esculenta (Aravi) crude extracts as intracanal medicaments with calcium hydroxide (CH), 2% chlorhexidine (CHX) gel, and 940 nm diode laser. Materials and methods: Fifty-eight intact, single-root, extracted human mandibular premolar teeth were prepared. The samples were sterilized, transferred into microcentrifuge tubes, and inoculated with E. faecalis. The samples were placed in an incubator for three weeks to allow the biofilm to grow. Then the samples were randomly divided into five experimental groups (n = 10), disinfected with Suran, Aravi crude extracts, CH, 2% CHX gel, and a 940 nm diode laser. The negative control group (n = 4) and the positive control group (n = 4). Then the samples were observed under light and scanning electron microscopy to monitor the E. faecalis biofilm. The sampling method was carried out in paper point (intracanal) and Peeso bur (intradentinal). Later the number of colony-forming units was counted and analyzed. Results: Colony-forming units were significantly reduced in the 2% CHX gel in both sampling methods, while Suran showed lower colony-forming units compared to Aravi and CH. The differences between experimental groups were not statistically significant (P > 0.05) in both sampling methods. Conclusion: This study showed that the application of Suran and Aravi crude extracts as intracanal medicaments leads to a significant reduction in the number of bacterial colonies compared to CH, 2% CHX gel, and 940 nm diode laser.

Microbial analysis of endodontic infections in teeth with post-treatment apical periodontitis before and after medication.

This study aimed to determine the intraradicular microbiota of previously root canal-treated teeth with apical periodontitis and to investigate the antibacterial effectiveness of different intracanal medicaments. Sixteen patients with post-treatment apical periodontitis were allocated into two groups according to the intracanal medicament used: calcium hydroxide (CH) and 2% chlorhexidine gluconate gel (CHX) group. Total bacterial loads, as well as the amount of Enterococcus faecalis (E. faecalis) were determined before (S1) and after (S2) chemomechanical preparation and finally, after intracanal medication (S3) by means of ddPCR. The unpaired t test was used to compare parametric. S3-total bacteria copy number of the CH group was lower than the CHX group (p < 0.05). There was no statistical difference between the CHX- and the CH groups in terms of E.faecalis copy number (p > 0.05). But in terms of total bacteria, CH is better than CHX. Consequently, CH can be used to optimise the antibacterial efficiency of chemomechanical preparation in previously root canal-treated teeth with apical periodontitis.

Long-term treatment of dentine with triple antibiotic paste promotes stem cell viability and attachment.

Objective: Successful regenerative endodontic procedures in dental treatment are critically associated with complete disinfection of the root canal and require irrigants and medicaments. One factor for consideration is the biocompatibility of the medicament as this can affect the intracanal dentine and subsequently the dental stem cell viability required for the repair of the dentine-pulp complex. This in vitro study investigated the effect of a 4-week treatment of calcium hydroxide [Ca(OH)2] and triple antibiotic paste (TAP) on the irrigated radicular dentine by analysing dentine interaction with dental stem cells. Methods: TAP consists of metronidazole, ciprofloxacin and minocycline. Dentine chips were prepared and treated with either Ca(OH)2 or TAP for 4-weeks, irrigated by 1.5% sodium hypochlorite (NaOCl), rinsed with saline, followed by 17% ethylenediaminetetraacetic acid (EDTA). Dental pulp stem cells (DPSCs) cultured on the surface of the dentine chips were analysed on days 1, 3 and 7 of cell seeding for PrestoBlue viability assays, 6-diamidino-2 phenylindole (DAPI) staining and scanning electron microscopy (SEM). An independent t-test (SPSS software version 24.0) was used to statistically analyse the PrestoBlue assay data. Results: DPSCs grown from dentine treated with TAP showed significantly higher cell viability than the Ca(OH)2 and control groups (p < 0.05). DAPI staining of the seeded DPSCs on the treated dental chips complemented the findings of the viability assay. SEM studies also revealed improvements in the cell spreading and attachment of DPSCs grown on TAP-treated dentine compared with Ca(OH)2. Conclusion: The treatment of dentine with TAP for 4 weeks provided a better microenvironment for the viability and attachment of DPSCs when compared to Ca(OH)2.

Carnosic Acid as an intracanal medicament performs better than triple antibiotic paste and calcium hydroxide to eradicate Enterococcus faecalis from root canal: An in vitro confocal laser scanning microscopic study.

Background: Carnosic acid is an herbal derivative with potent antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. Aim: Comparative evaluation of the antimicrobial potential of carnosic acid, calcium hydroxide, and triple antibiotic paste as intracanal medicaments against Enterococcus faecalis. Settings and Design: Department of Conservative Dentistry and Microbiology, an in vitro study. Materials and Methods: Fifty-two extracted single-rooted human teeth were decoronated and chemomechanical preparation was performed. The specimens were secured in the center of screw-capped vials and autoclaved. A strain of E. faecalis was inoculated into the canals and grown for 72 h. The teeth were divided into: Group I-Ca(OH)2, Group II- triple antibiotic paste (TAP), Group III-Carnosic acid, and Group IV-Negative control. The medicaments were applied in the canal and left for 14 days. The specimens were sectioned transversely at three levels to create dentinal discs and observed under the confocal laser scanning microscopic (CLSM). Images were analyzed, and quantification of bacteria was done using the Image J software. Statistical Analysis: Mean percentage of live/dead bacteria was analyzed using One-way ANOVA and Post hoc Tukey test. Results: Mean percentages of live and dead bacteria were seen under CLSM in Group I, Group II, and Group III were (4.44 ± 2.87, 4.56 ± 2.93, 1.61 ± 1.90), and (4.59 ± 3.04, 4.25 ± 2.98, 1.70 ± 1.99), respectively, with least mean percentages for live and dead bacteria in carnosic acid (Group III). Conclusion: Carnosic acid showed better antimicrobial efficacy against E. faecalis than TAP and Ca(OH)2 by showing a low percentage of both live and dead bacteria.

The effect of different intracanal medicaments on the dislodgement resistance of mineral trioxide aggregate.

BACKGROUND: This study aimed to assess the effect of different commercially used calcium hydroxide [Ca(OH)2], the mixture of Ca(OH)2 + silver nanoparticles (AgNPs), and other intracanal medicaments on dislodgement resistance of mineral trioxide aggregate (MTA) to root canal dentin in short- and long-term application. METHODS: Forty-six human single-rooted maxillary teeth were sectioned horizontally at mid-root into 1 mm thick slices. The lumen of the slices was standardized using #2-#5 Gates Glidden drills to a standard diameter of 1.3 mm in all samples. After smear layer removal, the samples were randomly divided into eight groups (n = 20) and treated with the following medicaments; Ca(OH)2 paste, Calcipex, Metapex, chlorhexidine (CHX), Ca(OH)2/CHX paste, Ca(OH)2/AgNPs, triple antibiotic paste and control group (normal saline). The samples were then incubated at 37 °C with 100% humidity for 1 week. Next, half of the teeth in each group (n = 10) were removed from the incubator and washed in an ultrasonic bath. ProRoot MTA was placed in the canal lumen and the samples were incubated at 37 °C and 100% humidity for 48 h to allow complete setting of MTA. The remaining half in each group (n = 10) was subjected to the same process after 1 month of application of medicaments. The dislodgement resistance of MTA to root dentin was measured. The data were analysed using two-way ANOVA and Tukey's post hoc test. RESULTS: No significant difference was noted in dislodgement resistance of samples after 1 week and 1 month in any group (P > 0.05). The only significant difference was noted between the control and CHX groups and the higher dislodgement resistance was recorded in the CHX group (P = 0.006). No other significant differences were noted between the groups (P > 0.05). CONCLUSION: Duration of application and the type of intracanal medicament do not affect the dislodgement resistance of MTA to root dentin. Although there was no statistically significant difference in the dislodgment resistance of MTA between the medicaments, CHX had a promising effect.

Effects of Intracanal Antimicrobials on Viability and Differentiation of Stem Cells From the Apical Papilla: An In Vitro Study.

BACKGROUND: Recent studies have indicated that intracanal antimicrobials used to disinfect the root canal in regenerative endodontic therapies (RETs) may be cytotoxic to stem cells from the apical papilla (SCAP), leading to inconsistent treatment outcomes. However, the effects of intracanal antimicrobial agents on the odontogenic differentiation capacity of SCAP at sub-lethal concentrations have not been investigated. The aim of this study was to determine the effects of intracanal antimicrobials on SCAP viability and odontogenic differentiation capacity using a clinically relevant concentration range (0.1-0.8 mg/mL). METHODS: Immature human third molars were collected from 71 patients and the apical papillae were harvested to form single-cell suspensions. The cytotoxic effects of intracanal antimicrobials including double antibiotic paste (DAP), triple or modified-triple antibiotic paste (TAP or MTAP), and calcium hydroxide (Ca(OH)2) on STRO-1+ SCAP were assessed using AlamarBlue and Live/Dead assays after exposing cells to treatment groups for 7 days at 0.1 to 0.8 mg/mL. The odontogenic differentiation potential of STRO-1+ SCAP was evaluated by immunocytochemistry staining of dentin matrix protein-1 and dentin sialophosphoprotein expression. RESULTS: All concentrations of TAP significantly reduced STRO-1+ SCAP viability and odontogenic differentiation (P < .001), whereas no DAP concentrations were significantly cytotoxic. Ca(OH)2 and MTAP concentrations below 0.4 mg/mL and 0.2 mg/mL, respectively, did not significantly reduce viability. The DAP, MTAP, and Ca(OH)2 did not significantly impact the odontogenic differentiation capacity of STRO-1+ SCAP. CONCLUSION: The varying effects of intracanal antimicrobials on STRO-1+ SCAP in vitro suggest amendments to the current root canal disinfection protocol may improve the success of RETs.

Intracanal calcification following regenerative endodontic treatment: a systematic review and meta-analysis.

OBJECTIVES: Calcification is a common finding in endodontic cases after regenerative endodontic therapy (RET). We aimed to identify the prevalence of intracanal calcification after RET and to compare intracanal calcification outcomes in RET using either calcium hydroxide [Ca(OH)2] or antibiotics. MATERIALS AND METHODS: We searched PubMed, Web of Science, ProQuest Dissertations & Theses, and Scopus databases for clinical, cross-sectional, case-control, and cohort RET studies published until May 2020 in the English language and reporting a calcified case after RET. The Cochrane risk-of-bias tool for randomized trials and Risk of Bias In Non-randomized Studies of Interventions were used for bias assessment. Meta-analyses were performed, overall and separately, for intracanal medicaments using a random-effects model with weighted inverse variance methods. Subgroup analysis was performed according to the calcification type. RESULTS: Eight studies were included. The overall prevalence of intracanal calcification after RET was 30.7% (95% confidence interval [CI]: 0.15-0.45,[Formula: see text]=92.6%), 46.5% with Ca(OH)2 vs. 25.8% with antibiotic-based intracanal medicaments. Subgroup analyses for complete calcification outcome showed a higher prevalence of complete calcification in the Ca(OH)2 group (46.5%, 95% CI: 0.17-0.68,[Formula: see text]%) than in the antibiotic group (10%, 95% CI: - 0.04-0.43,[Formula: see text]%). CONCLUSIONS: Based on the studies included, available evidence shows a statistically significant association between complete calcification and Ca(OH)2 paste as an intracanal medicament. Other contributing factors, such as blood clot formation and follow-up time, might also play an essential role in forming intracanal calcification. CLINICAL RELEVANCE: This study highlights the significant association between complete calcification and Ca(OH)2 paste.

The Use of Fiber-optic Transillumination in the Diagnosis of Fracture Line in Teeth: A Method of Standardization in Fracture Strength Studies.

The use of fiber optic transillumination (FOTI) has been witnessed in the clinical scenario for many decades but has not been used in in vitro studies. The present paper highlights the use of FOTI as a method of standardization while conducting fracture strength studies in vitro. How to cite this article: Chanchala HP, Godhi BS, Saha S. The Use of Fiber-optic Transillumination in the Diagnosis of Fracture Line in Teeth: A Method of Standardization in Fracture Strength Studies. Int J Clin Pediatr Dent 2022;15(4):475-477.

Effect of hydrogel-based antibiotic intracanal medicaments on crown discoloration.

OBJECTIVES: This study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration. MATERIALS AND METHODS: Intact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]2; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05. RESULTS: Ca(OH)2 and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used. CONCLUSIONS: Ca(OH)2 and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.

Antibacterial Activity of Various Intracanal Medicament against Enterococcus faecalis, Streptococcus mutans and Staphylococcus aureus: An In vitro Study.

AIM: The aim of this study was to evaluate and compare the antimicrobial efficacy of triple antibiotic paste (TAP), calcium hydroxide, and Odontopaste which are used as intracanal medicaments against Enterococcus faecalis, Streptococcus mutants, and Staphylococcus aureus. MATERIALS AND METHODS: Antibiotic sensitivity testing was done using agar well diffusion method of the following intracanal medicaments: Group 1: TAP (Ciprofloxacin, metronidazole, and doxycycline mixed in a ratio of 1:1:1; Group 2: Calcium hydroxide paste; Group 3: Odontopaste; Group 4: Sterile saline (0.9%) as a negative control. Each medicament was tested against E. faecalis, S. mutants, and S. aureus. The maximum zone of inhibition was noted by diameter size (mm) and analyzed with one-way ANOVA. RESULTS: TAP showed the highest zone of inhibition. There is no significant difference between Odontopaste and calcium hydroxide against E. faecalis and S. aureus. There is a significant difference between TAP, Odontopaste, and calcium hydroxide against S. mutants. The order of the highest zone of inhibition is TAP > Odontopaste>Calciumhydroxide. CONCLUSION: With in the limitations of the study, TAP had better antibacterial activity against E. faecalis, S. mutants, and S. aureus followed by odontopaste and calcium hydroxide, Hence, Odontopaste can be used as an alternative for calcium hydroxide in the infected root canal.

Comparative evaluation of the concentration-dependent effect of proton-pump inhibitor in association with calcium hydroxide and chlorhexidine on Enterococcus faecalis: An in vitro study.

BACKGROUND: Enterococcus faecalis is the most persistent organism in the root canal which resists most of the intracanal medicaments. There is always a constant attempt to eliminate this endodontic pathogen from the root canal system. AIM: The aim of this study was to evaluate the efficacy of the association of different concentrations of proton-pump inhibitor (PPI) (Lansoprazole) with calcium hydroxide (CH) and chlorhexidine (CHX) against E. faecalis using a broth dilution method. MATERIALS AND METHODS: E. faecalis was inoculated into brain-heart infusion broth at 37°C for 5 h. The master broth was then treated with CH (Group 1); CH + 2% CHX (Group 2); CH + PPI 6.25 µg/ml (Group 3A); CH + PPI 25 µg/ml (Group 3B); 2% CHX + PPI 6.25 µg/ml (Group 4A); 2% CHX + PPI 25 µg/ml (Group 4B); CH + 2% CHX + PPI 6.25 µg/ml (Group 5A), and CH + 2% CHX + PPI 25 µg/ml (Group 5B). The groups were spectrophotometrically analyzed at 630 nm at 24 h to determine the group with the least optical density. STATISTICAL ANALYSIS: Comparison between the groups was done by the one-way analysis of variance and Kruskal-Wallis test for multiple comparisons. RESULTS: The mean percentage inhibition of E. faecalis by Group 5A (CH + 2% CHX + PPI 6.25 µg/ml) was the highest compared to other groups. The lowest mean value was observed in Group 3A (CH + PPI 6.25 µg/ml) indicating least efficiency. CONCLUSION: There was a concentration-dependent effect of PPI on CH and CHX against E. faecalis. The maximum efficacy was found when the lower concentration of PPI was associated with CH/CHX mixture.

Characterization of Histopathology and Microbiota in Contemporary Regenerative Endodontic Procedures: Still Coming up Short.

INTRODUCTION: This study aimed to investigate microbiota and the histopathology of infected immature teeth microenvironments after disinfection with calcium hydroxide, triple antibiotic paste, and a synthetic antimicrobial peptide (synthetic human beta-defensin-3-C15) for regenerative endodontic procedures (REPs). The null hypothesis was that there is no difference among intracanal medications on disinfection in REPs. METHODS: Pulp necrosis and periapical lesions were induced in immature beagle dog premolars. Block randomized teeth were uninfected (negative control, n = 6), left infected (positive control, n = 6), or medicated with a disinfectant (n = 6/group). After disinfection (2 weeks), teeth were reaccessed, irrigated with 17% EDTA, blood clot induced, sealed with ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), and restored with resin-modified glass ionomer. Animals were monitored radiographically and euthanized (12 weeks) for histopathologic and metagenomic analyses. RESULTS: REP-treated roots showed radiographic repair of periapical radiolucency (67.65%, 23/34), continued root development (73.53%, 25/34), and apical closure (70.59%, 24/34) regardless of the disinfectant used (P > .05). Canal microenvironments histologically devoid of bacteria contained new mineralized and pulp-like tissues in characteristic patterns that varied by disinfectant. Next-generation sequencing (16S ribosomal RNA) identified Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes as dominant phyla of microbiota in immature teeth. Infection-induced teeth showed changes in diversity and richness of microbiota from negative controls. Compared with positive controls, all treated teeth exhibited depleted operational taxonomic units, with lower phylogenic diversity from synthetic human beta-defensin-3-C15-treated teeth. CONCLUSIONS: There were no differences among the medicaments investigated in radiologic treatment outcomes, but disinfectants in REPs showed altered microbiota from normal and diseased immature teeth with different histologic patterns of regeneration.

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

BACKGROUND: The successful outcome of endodontic treatment depends on controlling the intra-radicular microbial biofilm by effective instrumentation and disinfection using various irrigants and intracanal medicaments. Instrumentation alone cannot effectively debride the root canals specially due to the complex morphology of the root canal system. A number of antibiotics and surfactants are being widely used in the treatment of biofilms however, the current trend is towards identification of natural products in disinfection. The aim of the study was to determine the antibacterial effect of chitosan-propolis nanoparticle (CPN) as an intracanal medicament against Enterococcus faecalis biofilm in root canal. METHODS: 240 extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into eight groups (n = 30) according to the intracanal medicament placed: group I: saline, group II: chitosan, group III: propolis100 µg/ml (P100), group IV: propolis 250 µg/ml (P250), group V: chitosan-propolis nanoparticle 100 µg/ml (CPN100), group VI: chitosan-propolis nanoparticle 250 µg/ml (CPN250), group VII: calcium hydroxide(CH) and group VIII: 2% chlorhexidine (CHX) gel. Dentine shavings were collected at 200 and 400 µm depths, and total numbers of CFUs were determined at the end of day one, three and seven. The non-parametric Kruskal Wallis and Mann-Whitney tests were used to compare the differences in reduction of CFUs between all groups and probability values of p < 0.05 were set as the reference for statistically significant results. The scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to CPNs. The effectiveness of CPNs were also evaluated against E. faecalis isolated obtained from patients having failed root canal treatment. RESULTS: The treatments of chitosan, P100, P250, CPN100, CPN250, CH and 2% CHX reduced the CFUs significantly compared to saline (p < .05). On day one and three, at 200 and 400-µm, CPN250 showed significant reduction of CFUs compared to all other groups (p < .05), while CPN100 was significantly better than other groups (p < .05) except CPN250 and 2% CHX. On day seven, at 200-µm CPN250 showed significant reduction of CFUs compared to all other groups (p < .05) except CPN100 and CHX, while at 400 µm CPN250 showed similar effectiveness as CPN100, CH and 2% CHX. SEM images showed root canal dentin treated with CPN250 had less coverage with E. faecalis bacteria similarly, CLSM images also showed higher percentage of dead E. faecalis bacteria with CPN250 than to CPN100. CONCLUSION: CPN250 was the most effective in reducing E. faecalis colonies on day one, three at both depths and at day seven CPN250 was equally effective as CPN100 and 2% CHX.

The Effects of Intracanal Irrigants and Medicaments on Dental-Derived Stem Cells Fate in Regenerative Endodontics: An update.

Regenerative endodontics is a biologically based treatment designed for immature permanent teeth with necrotic pulp to replace dentin and root structures, as well as dental pulp cells. This procedure has become a part of novel modality in endodontics therapeutic manner, and it is considered as an alternative to apexification. In the last decade, numerous case reports, which describe this procedure, have been published. This therapeutic approach succeeded due to its lower financial cost and ease of performance. Although the clinical protocol of this procedure is not standardized and the effects of irrigants and medicaments on dental stem cells fate remain somewhat ambiguous, however when successful, it is an improvement of endodontics treatment protocols which leads to continued root development, increased dentinal wall thickness, and apical closure of immature teeth. To ensure a successful regenerative procedure, it is essential to investigate the appropriate disinfection protocols and the use of biocompatible molecules in order to control the release of growth factors and the differentiation of stem cells. This is the first review in the literature to summarize the present knowledge regarding the effect of intracanal irrigants and medicaments on the dental derived stem cells fate in regenerative endodontic procedures.

Effect of duration and dilution on antimicrobial efficacy of octenidine hydrochloride as an intracanal medicament with chitosan carrier against Enterococcus faecalis - A modified direct contact test.

BACKGROUND: The ambiguity in key influential factors such as minimal time for effective action, dilution, and need of drug carrier for intracanal medicaments necessitates a microbial analysis that aids in the potential selection of an intracanal medicament for ensuring optimal root canal disinfection. AIMS: This study aims to evaluate the antimicrobial efficacy of octenidine hydrochloride (OHC) and gold standard calcium hydroxide (Ca(OH) 2) as intracanal medicaments, both independently and along with chitosan (CTS) as medicament vehicle against the common resistant endopathogen - Enterococcus faecalis. MATERIALS AND METHODS: A modified direct contact microbial test was used to evaluate the amount of surviving bacteria after predetermined contact time (2, 5, 20, and 60 min) and 5-fold serial dilution of the intracanal medicaments. The experiment was carried out under aseptic conditions and performed in triplicate to ensure reproducibility. STATISTICAL ANALYSIS USED: The results were analyzed by Kruskal-Wallis analysis of variance followed by pairwise comparisons by Mann-Whitney U-test. RESULTS AND CONCLUSIONS: The results showed that all the four medicament groups were able to show the maximum antimicrobial efficacy against E. faecalis at 60 min time interval and that the antimicrobial efficacy of OHC and Ca(OH) 2 was at its peak when used alone. The study thereby concluded that the addition of CTS as a carrier did not enhance the antimicrobial efficacy of OHC or Ca(OH) 2 against E. faecalis.

Micro-computed tomographic analysis of the marginal adaptation of a calcium silicate-based cement to radicular dentin after removal of three different intracanal medicaments - An in vitro study.

CONTEXT: This study focuses on the marginal adaptation of a calcium silicate-based cement to the root dentin after retrieval of different intracanal medicaments. AIM: This study compared the marginal adaptation of a calcium silicate-based cement to radicular dentin in the apical third of the root canal following the use of three different intracanal medicaments. MATERIALS AND METHODS: Forty single-rooted premolar teeth (n = 40) were decoronated 13 mm above the root apices; then, 3 mm of the root tips were resected to standardize the root length. Orthograde cleaning and shaping were done using the rotary files and apical enlargement using peeso reamers. Depending on the intracanal medicament used, the samples were equally divided into four groups: Group 1 - control, Group 2 - Metapex, Group 3 - triple antibiotic paste (TAP), and Group 4 - calcium hydroxide with Propolis. Subsequently, the medicament was removed and a 3 mm apical barrier of BiodentineTM was placed and later scanned using an ex vivo micro-computed tomography scanner. STATISTICAL ANALYSIS USED: One-way ANOVA F-test and Tukey's post hoc test were used. RESULTS: Maximum adaptation was seen in control group (0.65) > Propolis (1.47) > TAP (4.37) > Metapex (5.25); a high statistically significant difference between the four groups was found (P < 0.001) with regard to the external voids between BiodentineTM and radicular dentin. CONCLUSION: On comparison of the marginal adaptation of Biodentine to root canal dentin following the use of three different intracanal medicaments, maximum adaptation was seen in Group 1, followed by Group 4, Group 3, and Group 2.