Evaluation of Cytotoxic Effects of Various Endodontic Irrigation Solutions on the Survival of Stem Cell of Human Apical Papilla

Introduction: Root canal disinfection is an important step in regenerative endodontic treatments. An ideal irrigating solution must have high antimicrobial activity and minimum cytotoxicity. This study sought to assess the effect of some irrigating solutions on stem cells from the human apical papilla (SCAP) after different periods of exposure. Methods and Materials: Stem cells were isolated from immature, impacted mandibular third molars, transferred to 24-well plates, randomly divided into 6  experimental groups and exposed to BioPure MTAD Cleanser, QMix, 17% EDTA, 2% chlorhexidine (CHX), 5.25% sodium hypochlorite (NaOCl), sterile saline and untreated control group. Cytotoxicity of these solutions was assessed after 1, 5 and 15 min of exposure using the methyl thiazol tetrazolium (MTT) assay. Data were statistically analyzed using repeated measures ANOVA. Level of significance was set at 0.05. Results: The mean percentage of viable cells in all experimental groups was significantly different from the control and sterile saline groups at all the time points (P<0.0001). The mean percentage of viable cells significantly decreased over time in NaOCl, QMix, EDTA and MTAD groups, but no significant reduction was noted in CHX group. At all the time points the highest and the lowest cytotoxicity were seen in MTAD and normal saline groups, respectively. Cytotoxicity of the understudy materials from the highest to the lowest was as follows: MTAD>EDTA>QMax=NaOCl>CHX> sterile saline. Conclusion: Chlorhexidine had the lowest cytotoxicity compared to EDTA, MTAD, QMix and NaOCl and its cytotoxicity did not change over time compared to other solutions.Keywords: Apical Papilla; Cytotoxicity; Irrigating Solution; MTT Assay; Stem Cell

Cytotoxicity of Endodontic Irrigants on Human Periodontal Ligament Cells

Introduction: Root canal irrigation has an extremely important role in the success of endodontic treatment. During endodontic treatment, the irrigants will be in contact with pulpal and periapical tissues. The purpose of this study was to clarify the potential toxicological implications of NaOCl, EDTA, MTAD, CHX and QMix on periapical and periodontal tissues. Methods and Materials: Cytotoxicity of solutions was evaluated on cultured human periodontal ligament (hPDL) that were carefully removed from the middle third of premolar roots. Cytotoxicity of the materials was assessed after 1, 5 and 15 min of exposure using the Mosmann’s Tetrazolium Toxicity (MTT) assay. Optical density of the solution was read at 540-690 nm wavelength. The intensity of color generated correlated with the percentage of viable cells. Data were statistically analyzed using repeated measures ANOVA followed by Bonferroni test. Results: The mean percentage of viable cells in all experimental groups was significantly different from sterile saline groups at all time points (P<0.0001). The mean percentage of viable cells significantly decreased over time in MTAD and NaOCl groups. The lowest and highest cytotoxicity belonged to MTAD and EDTA groups, respectively at all the time points (P<0.05). Conclusion: MTAD had the lowest cytotoxicity compared to NaOCl, CHX, QMix and EDTA. These impacts have been time dependent. These irrigation fluids may cause unfavorable effects on vital tissues. Keywords: Cytotoxicity Test; MTT Tetrazolium; Periodontal Ligament; Root Canal Irrigant

Iatrogenic Errors during Root Canal Instrumentation Performed by Dental Students

Introduction: The present study was set to investigate the training quality and its association with the quality of root canal therapy performed by fifth year dentistry students. Methods and Materials: A total number of 432 records of endodontic treatment performed by fifth year dentistry students were qualified to be further investigated. Radiographs were assessed by two independent endodontists. Apical transportation, apical perforation, gouging, ledge formation, and the quality of temporary restoration were error types investigated in the present study. Results: the prevalence of apical transportation, ledge formation, and apical perforation errors were significantly higher in molars in comparison with other types of teeth. The most prevalent type of error was the apical transportation, which was significantly higher in mandibular teeth. There was no significant differences among teeth in terms of other types of errors. Conclusion: The quality of training provided for dentistry students should be improved and endodontic curriculum should be modified.Keywords: Dental Students; Procedural Errors; Root Canal Therap

Cytotoxicity of Various Endodontic Materials on Stem Cells of Human Apical Papilla

Introduction: This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP). Methods and Materials: SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05. Results: Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (P<0.05) although the cytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (P<0.05). Conclusion: CEM, OCP, BD and MTA showed acceptable biocompatibility when exposed to SCAP. Over time, CEM showed the least cytotoxicity among the materials under study.Keywords: Biodentine; Calcium-Enriched Mixture; Cytotoxicity; Endodontic Biomaterials; Mineral Trioxide Aggregate; MTT Assay; Stem Cells of Apical Papill

Comparative effects of Er:YAG laser, and EDTA, MTAD, and QMix irrigants on adhesion of stem cells from the apical papilla to dentin : a scanning electron microscopic study

Dentin conditioning can affect the adhesion of stem cells in endodontic regenerative treatments. This study aimed to assess the effects of the most commonly used endodontic irrigants, namely, ethylenediaminetetraacetic acid (EDTA), MTAD, and QMix in comp

Combination of Dental Capping Agents With LowLevel Laser Therapy Increases the Cell Viability Percent of Stem Cells From Apical Papilla (SCAPs)

Introduction: Stem cells from apical papillae (SCAPs) are adult stem cells capable of differentiating into multiple cell lineages. Dental pulp capping materials promote the differentiation of stem cells of the apical papilla (SCAPs). Higher proliferation and cell viability of stem cells have been reported upon exposure to low-level laser therapy (LLLT). However, there is limited evidence on the combinational effects of dental pulp capping materials and low-level laser radiation. In this study, the effects of dental dressing materials combined with laser on the SCAPs viability will assess. Methods: SCAPs isolation was performed from two immature third molar teeth through collagenase type I enzymatic activity. Isolated stem cells were then cultured with DMEM and α-MEM media enriched with 15% and 10% FBS, respectively. After reaching 70-80% confluency, cells were seeded in a 96-well plate. Cell viability percent was assessed using MTT assay after treatment by MTA, EMD, CEM, and LLLT alone and in combination for 24, 48, and 168 h. Results: A combination of MTA, CEM, EMD, and LLLT could result in significantly increased SCAPs viability as compared with other treatment groups. Increased levels of SCAPs proliferation and viability were observed in groups treated with the combination of MTA and CEM with EMD. SCAPs viability percent in all defined times was reduced with MTA and CEM treatment. Conclusion: LLLT is a stimulator of SCAPs cell viability percent and differentiation rate when applied with dental capping agents such as MTA, EMD, and CEM, which is a therapeutic option for stem cell-based therapy

Radiographic Quality of Root Canal Obturation Performed By Fifth Year Students of Hamadan Dental School

Introduction: The aim of this study was to assess the radiographic technical quality of root canal therapy performed by fifth year students of Dental School of Hamadan University of Medical Sciences from 2015 to 2016. Methods and Materials: Four hundred and seventy records of root canal therapies were evaluated. Records with graphies taken as initial, master apical file (MAF), master apical cone (MAC) and final radiographs were included in the study and records of patient younger than 16 years and older than 68 years were excluded from further investigations. Lastly, 432 teeth were selected. Obturation length, canal tapering, quality and density of filling material were the variables investigated in the present study. Two independent investigators examined the radiographies using a magnifying lens (×2) and x-ray viewer. Data were analyzed using chi-square test. Results: The technical quality of root filling performed by undergraduate dental students was classified as acceptable in 10.4% of cases. Moreover, 70.8% of teeth had adequate filling, 17.1% were underfilled and 12% were overfilled. The three groups were significantly different in terms of working length and taper quality. One hundred ninety four (44.9%) records had adequate taper and 109 (25%) records had adequate density. There was a significant association between teeth location and the length of obturation so that the probability of a successful treatment was higher in maxillary teeth. Furthermore, the rate of a proper length of obturation was higher among incisors than that of premolars and molars. Conclusion: The technical quality of root canal therapy performed by dental students in Hamadan University of medical sciences is not as acceptable as it should be. One of the most important factors in this regard is a high student/professor ratio.Keywords: Dental Students; Quality Control; Root Canal Obturation; Root Canal Therap

Effect of Low-Level Laser Therapy on Differentiation and Proliferation of Human Dental Pulp Stem Cells: A Systematic Review: Effect of LLLT on pulp stem cells

Introduction: Considering the positive impact of laser treatment on the proliferation of certain cell types, we opted to perform a systematic review aimed at evaluating the effects of laser therapy and photobiomodulation on the proliferation and differentiation of human dental pulp stem cells (hDPSCs).Methods: We included all research studies examining the impact of laser therapy on hDPSCs, without limitations on publication dates or article languages. The major international databases, including PubMed, ISI Web of Science, and Scopus, were searched from inception to April 2022 by the relevant keywords.Results: In total, 1886 studies were identified in the initial search from the mentioned databases and other sources. Finally, 17 relevant studies were included in the present systematic review after removing duplicates and non-relevant articles. The results indicated the useful effect of low-level laser therapy (LLLT) on the hDPSCs.Conclusion: The findings of this systematic review indicate the useful role of LLLT in cell therapy, proliferation, and differentiation associated with hDPSCs

The effect of low-dose aspirin on aspirin triggered lipoxin, interleukin 1 beta, and prostaglandin E2 levels in periapical fluid: a double-blind randomized clinical trial

Abstract Background The role of pro-resolving mediators in inflammation is a new concern in research. The effect of low-dose aspirin on production of a special kind of these mediators named aspirin triggered lipoxin (ATL) has been studied on different tissues. This randomized clinical trial evaluated the effect of low-dose aspirin on ATL and pro-inflammatory mediators’ level in periapical fluid of necrotic teeth with large lesions. Methods Twenty-four patients with necrotic pulp and periapical lesion were randomly assigned to low-dose aspirin and placebo groups. In the first appointment, canals were shaped up to F3 size and #40 K-file and cleaned with 10 milliliters 2.5% sodium hypochlorite and 17% Ethylenediaminetetraacetic acid. Periapical fluid was sampled by a paper cone. The tooth was temporized without any intracanal medication. Tablets were administered for 7 days, then the teeth were re-opened and the sampling were repeated. Interleukin-1 beta (IL-1β), prostaglandin E2 (PGE2) and ATL were analyzed by enzyme-linked immunosorbent assay. Data were analyzed with paired t-test using SPSS statistical software, version 21 (α = 0.05). Results A significant reduction in PGE2 and IL-1β was noted in the aspirin-treated group while an increase in ATL was observed (P  0.05). Conclusion Low-dose aspirin can influence the inflammatory process by reducing pro-inflammatory mediators such as PGE2 and IL-1β, as well as increasing the pro-resolving mediators such as ATL. Trial registration IRCT20191211045702N1