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Aim: To evaluate M1 and M2 macrophage polarization in radicular cysts and periapical granulomas through an immunohistochemical analysis and the correlation between macrophage polarization and histopathological diagnosis, clinical characteristics and lesion volume using cone-beam computed tomography., Methodology: Periapical biopsies diagnosed as radicular cysts (n = 52) and periapical granulomas (n = 51) were analysed by immunohistochemical method. Teeth with periapical lesion with no history of root canal treatment (primary lesion) and lesions persistent to root canal treatment (persistent lesions) were included. Pathological diagnosis, patients' age, gender and clinical characteristics were obtained from treatment records. A cone-beam computed tomographic periapical volume index (CBCTPAVI) score was assigned to each periapical lesion based on the volume of the lesion. Immuno-expressions of CD68 and CD163 were quantified. The CD68/CD163 ratio was adopted to represent M1 or M2 macrophage polarization. Mann-Whitney U test was used to determine the different CD68/CD163 ratio between groups of radicular cyst and periapical granuloma. Spearman's correlation test was performed to assess the correlation between the CD68/CD163 ratio and lesion volume and CBCTPAVI score., Results: Radicular cysts and periapical granulomas had CD68/CD163 median of 2.05 (IQR = 1.33) and 1.26 (IQR = 0.81), respectively. A significantly higher CD68/CD163 ratio was observed in radicular cysts (p < .001). In contrast, periapical granulomas had significantly lower median of CD68/CD163 ratio. Larger lesions had a higher median of CD68/CD163 ratio, while smaller lesions had lower median of CD68/CD163 ratio (p = .007, r s  = .262). CD68/CD163 ratio was significantly correlated with the CBCTPAVI score in the overall periapical lesions (p = .002, r s  = .306). The higher CD68/CD163 ratio in larger lesions indicated a higher degree of M1 polarization compared to smaller lesions. Regarding the pathological diagnosis, there was a significant positive correlation between CBCTPAVI score and CD68/CD163 ratio in periapical granulomas (p < .001, r s  = .453), whereas the negative correlation was observed for radicular cysts (p < .001, r s  = -.471)., Conclusions: Periapical granulomas are characterized by a M2-dominant macrophage polarization, while radicular cysts have significantly higher M1 macrophages. The higher degree of M1 macrophage polarization was significantly correlated with larger volume and higher CBCTPAVI scores of overall periapical lesion and periapical granuloma., (© 2024 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Infection of the root canals with cross-kingdom biofilm of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) causes more inflammation and is resistant to conventional medication. This study aimed to evaluate the efficacy of chitosan paste (chitosan + propylene glycol (PG)) against this dual-species biofilm in comparison to calcium hydroxide (Ca(OH) 2 ) in the root canals of human teeth. Fifty extracted single-rooted human teeth were prepared and inoculated with C. albicans and E. faecalis, and incubated for 3 days for biofilm formation. Four experimental groups (N = 10 each) were applied with different root canal medications for 7 days, including (1) No medication (negative control); (2) Ca(OH) 2  + distilled water; (3) PG (vehicle control) and (4) chitosan + PG. The efficacy of root canal medicaments was assessed by determining the percentage of remaining colony-forming units (CFUs) of viable microorganisms in intracanal dentin. The dentin was collected, serially diluted, and spread on solid media for colony count. The biofilm structure in root canals at 3 days and 10 days (ie. before and after treatments) were observed with scanning electron microscopy (SEM) at 5000× and 10,000× magnifications. Data were analyzed using Welch's ANOVA and Games-Howell post-hoc test (α = 5%). The results show that Chitosan + PG group had a significantly lower percentage of remaining microorganisms when compared to PG, Ca(OH) 2 , and negative control groups (P-value = 0.015, 0.005, and < 0.001, respectively). Consistently, SEM showed the lowest amount of remaining biofilm in Chitosan + PG group. Thus, Chitosan + PG paste was the most efficacious root canal medicament against dual-species biofilm of C. albicans and E. faecalis in this model., Competing Interests: Declarations Conflict of interest The authors declare no conflict of interests. Ethical approval This study was granted an exemption by the Ethics Review Committee for Research, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand (Certificate of Exemption No.111/2022). Informed consent Not applicable., (© 2024. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Background: Enterococcus faecalis and Candida albicans are frequently found in persistent endodontic infection and could remain in dentinal tubules despite intracanal medication with calcium hydroxide (Ca(OH) 2 ), a commonly used medication. Thus, an effective and safe antimicrobial medication against such refractory infection is necessary in endodontic retreatment, so we aimed to test the efficacy of chitosan paste against these microorganisms compared with Ca(OH) 2 in root canals of extracted human teeth., Methods: Thirty-six sterilized human root samples prepared from extracted premolars and upper maxillary incisors were infected with E. faecalis for 14 days, while 32 were infected with C. albicans for 48 h, for mature biofilm formation. The samples were assigned to 6 groups of intracanal medications: Group 1: no medication (negative control); Group 2: 20% Polyethylene glycol (PEG); Group 3: 20% Propylene glycol (PG); Group 4: Ca(OH) 2 ; Group 5: Chitosan + PEG; and Group 6: Chitosan + PG. After 7 days, intracanal surface dentin was harvested using Protaper next, resuspended, serially diluted and spread on Brain-Heart-Infusion agar (for E. faecalis) and Yeast Extract-Peptone-Dextrose agar (for C. albicans) for colony count. Antimicrobial efficacy was determined as percentage of remaining colony forming unit (CFUs) relative to negative control and analyzed using One-way ANOVA and post-hoc Games-Howell test. The significance level was set at 0.05., Results: For E. faecalis, chitosan + PG had significantly higher antibacterial activity than Ca(OH) 2 (P = 0.039). Chitosan + PEG and chitosan + PG medication significantly reduced viable bacteria compared with negative control, PEG and PG (P = 0.001, 0.003, 0.024, respectively for chitosan + PEG; P = 0.002, 0.003, 0.014, respectively for chitosan + PG). For C.albicans, chitosan + PEG and chitosan + PG were not significantly different from Ca(OH) 2 . However, Chitosan + PEG and chitosan + PG, but not Ca(OH) 2 , showed a significantly lower level of remaining CFUs compared with negative control (P = 0.013 and 0.005, respectively)., Conclusion: Chitosan paste showed better efficacy in reducing viable E. faecalis biofilm when compared to Ca(OH) 2 after 7-day intracanal medication in this in vitro root canal model. It could also significantly reduce viable C. albicans, but was not significantly different from Ca(OH) 2 ., (© 2022. The Author(s).)

Objective: The purpose of this study was to evaluate pH and calcium ion release at the outer dentin surface of simulated external root resorption cavities after root canals obturated with bioceramic root canal sealer compared with those medicated with calcium hydroxide., Materials and Methods: Sixty extracted human single-rooted teeth were selected and instrumented. External root resorption cavities were prepared at the lingual surface of the root. The teeth were randomly divided into three groups: (1) Bioceramic sealer group, canals were obturated with gutta-percha and BioRoot sealer; (2) Calcium hydroxide group, canals were medicated with UltraCal XS; (3) Control group, canals were left empty. Thirty specimens were used for evaluation of pH at 7, 14, and 28 days (n = 10 per group) and the other 30 specimens were used for evaluation of calcium ion diffusion at 28 days (n = 10 per group)., Results: Calcium hydroxide group showed the highest median pH value at all time points (7, 14, and 28 days). Both calcium hydroxide and bioceramic sealer groups showed significantly higher median pH values compared with control (p < .001). Comparing within groups, both bioceramic sealer group and calcium hydroxide group showed significantly decreased median pH over time, while the median pH of the control did not show any significant difference among Days 7, 14, and 28. Both calcium hydroxide and bioceramic sealer groups had significantly higher calcium ion release than control. Notably, bioceramic sealer group showed significantly higher calcium ion release than the calcium hydroxide group (p < .01)., Conclusions: Root canals obturated with gutta-percha and bioceramic sealer showed high calcium ion levels at the simulated external root resorption cavities but did not show an extended period of alkaline pH., (© 2022 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

To investigate applications of chitosan as antibacterial agent for endodontic treatments, we tested its activity against Enterococcus faecalis standard strain (ATCC29212) and clinical isolates. We determined the minimum bactericidal concentration (MBC) of 6 types of chitosan against ATCC29212; the most effective types were selected for further tests. Four clinical isolates were cultured from endodontically treated-teeth and identified by biochemical assays and polymerase chain reactions. Bacterial cultures were exposed to 1,700 and 2,100 kDa chitosan at MBC for 1, 3, 5, 10, and 60 min in time-kill assays and plated on brain-heart-infusion (BHI) agar for colony counts. Both types of chitosan showed significantly lower numbers of remaining bacteria (log colony forming units per millimeter, logCFUs/mL) than negative controls (0.1% acetic acid and BHI) at 10 min, and completely eliminated the bacteria at 60 min for all strains. Thus, chitosan could be developed as alternative biocompatible antimicrobial irrigant/medication for endodontic treatments.

Introduction: Understanding tooth anatomy is crucial for effective endodontic treatment. This study investigated the roots and root canal morphology of maxillary first and second permanent molars in a Thai population using cone-beam computed tomographic (CBCT) imaging., Methods: This study evaluated 476 maxillary first molars and 457 maxillary second molars receiving CBCT examination and determined the number of roots and canal morphology according to Vertucci's classification, and the prevalence of a second mesiobuccal (MB2) canal in the mesiobuccal (MB) root was correlated with sex, age, and tooth side., Results: Three roots were most commonly found in maxillary first and second molars. MB2 canals in the MB root were found in 63.6% and 29.4% of first and second molars, respectively. The most common canal morphology in the first molar MB roots was type I (36.4%) followed by type II (28.8%), and type IV (25.3%). The most common canal morphology in the second molar MB roots was type I (70.6%) followed by type II (14.6%) and type IV (7.5%). Bilateral MB2 canals in the MB roots were present in 80.93% and 82.59% of the first and second molars, respectively. There was a significant correlation between males and the prevalence of MB2 canals in first molars (P < .05)., Conclusions: CBCT imaging is useful to determine root canal morphology. The prevalence of MB2 canals is approximately 60% and 30% in first and second molars, respectively. Furthermore, bilateral MB2 canals were commonly found. Our results can help endodontists to improve endodontic treatment outcomes., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study aimed to investigate the effect of epigallocatechin-3-gallate (EGCG) from green tea extract on the push out bond strength of an epoxy resin sealer to root dentin. Seventy single root canal premolars were decoronated and instrumented. The roots were randomly irrigated with different final irrigation protocols (n=16): 17%EDTA (EDTA), 17%EDTA followed by 2.5%NaOCl (EDTA+NaOCl), 17%EDTA followed by 1 mg/mL EGCG (EDTA+EGCG) and 1 mg/mL EGCG (EGCG). Other six root canals were received only 2.5%NaOCl as a control group. One root from each group (n=1) was excluded and prepared for SEM investigation. All root canals were then obturated and horizontally sectioned to perform the push out test. EDTA+EGCG group had the highest bond strength (p<0.05). EGCG group showed higher bond strength than EDTA group (p<0.05). The use of EGCG as a final irrigant significantly increased the push out bond strength of an epoxy resin sealer to root dentin.