Deep learning for determining the difficulty of endodontic treatment: a pilot study.

BACKGROUND: To develop and validate a deep learning model for automated assessment of endodontic case difficulty from periapical radiographs. METHODS: A dataset of 1,386 periapical radiographs was compiled from two clinical sites. Two dentists and two endodontists annotated the radiographs for difficulty using the "simple assessment" criteria from the American Association of Endodontists' case difficulty assessment form in the Endocase application. A classification task labeled cases as "easy" or "hard", while regression predicted overall difficulty scores. Convolutional neural networks (i.e. VGG16, ResNet18, ResNet50, ResNext50, and Inception v2) were used, with a baseline model trained via transfer learning from ImageNet weights. Other models was pre-trained using self-supervised contrastive learning (i.e. BYOL, SimCLR, MoCo, and DINO) on 20,295 unlabeled dental radiographs to learn representation without manual labels. Both models were evaluated using 10-fold cross-validation, with performance compared to seven human examiners (three general dentists and four endodontists) on a hold-out test set. RESULTS: The baseline VGG16 model attained 87.62% accuracy in classifying difficulty. Self-supervised pretraining did not improve performance. Regression predicted scores with ± 3.21 score error. All models outperformed human raters, with poor inter-examiner reliability. CONCLUSION: This pilot study demonstrated the feasibility of automated endodontic difficulty assessment via deep learning models.

Effect of Low-Level Diode Laser and Red Light-Emitting Diode on Survival and Osteogenic/Odontogenic Differentiation of Human Dental Pulp Stem Cells.

Background: This investigation set out to compare the impacts of low-level diode laser (LLDL) and red light-emitting diode (LED) on the survival of human dental pulp stem cells (hDPSCs) and osteogenic/odontogenic differentiation. Methods and materials: In this ex vivo experimental study, the experimental groups underwent the irradiation of LLDL (4 J/cm2 energy density) and red LED in the osteogenic medium. Survival of hDPSCs was assessed after 24 and 48 h (n = 9) using the methyl thiazolyl tetrazolium (MTT) assay. The assessment of osteogenic/odontogenic differentiation was conducted using alizarin red staining (ARS; three repetitions). The investigation of osteogenic and odontogenic gene expression was performed at two time points, specifically 24 and 48 h (n = 12). This analysis was performed utilizing real-time reverse-transcription polymerase chain reaction (RT-PCR). The groups were compared at each time point using SPSS version 24. To analyze the data, the Mann-Whitney U test, analysis of variance, Tukey's test, and t-test were utilized. Results: The MTT assay showed that LLDL significantly decreased the survival of hDPSCs after 48 h, compared with other groups (p < 0.05). The qualitative results of ARS revealed that LLDL and red LED increased the osteogenic differentiation of hDPSCs. LLDL and red LED both upregulated the expression of osteogenic/odontogenic genes, including bone sialoprotein (BSP), alkaline phosphatase (ALP), dentin matrix protein 1 (DMP1), and dentin sialophosphoprotein (DSPP), in hDPSCs. The LLDL group exhibited a higher level of gene upregulation (p < 0.0001). Conclusions: The cell survival of hDPSCs was reduced, despite an increase in osteogenic/odontogenic activity. Clinical relevance: Introduction of noninvasive methods in regenerative endodontic treatments.

Effect of magnesium oxide nanoparticles and LED irradiation on the viability and differentiation of human stem cells of the apical papilla.

PURPOSE: Currently, regenerative endodontic treatments are gaining more and more attention, and stem cells play a significant role in these treatments. In order to enhance stem cell proliferation and differentiation, a variety of methods and materials have been used. The purpose of this study was to determine the effects of magnesium oxide nanoparticles and LED irradiation on the survival and differentiation of human stem cells from apical papilla. METHODS: The MTT test was used to measure the cell survival of SCAPs that had been exposed to different concentrations of magnesium oxide nanoparticles after 24 and 48 h, and the concentration with the highest cell survival rate was picked for further studies. The cells were classified into four distinct groups based on their treatment: (1) control, which received no exposure, (2) exposure to magnesium oxide nanoparticles, (3) exposure to light emitting diode (LED) irradiation (635 nm, 200 mW/cm2) for 30 s, (4) exposure simultaneously with magnesium oxide nanoparticles and LED irradiation. A green approach was employed to synthesize magnesium oxide nanoparticles. Quantitative real time PCR was used to measure the gene expression of osteo/odontogenic markers such as BSP, DSPP, ALP and DMP1 in all four groups after treatment, and Alizarin red S staining (ARS) was used to determine the osteogenic differentiation of SCAPs by demonstrating the Matrix mineralization. RESULTS: The highest viability of SCAPs was observed after 24 h in concentration 1 and 10 µg/mL and after 48 h in concentration 1 µg/mL, which were not significantly different from the control group. In both times, the survival of SCAPs decreased with increasing concentration of magnesium oxide nanoparticles (MgONPs). According to the results of Real-time PCR, after 24 and 48 h, the highest differentiation of BSP, DMP1, ALP and DSPP genes was observed in the LED + MgONPs group, followed by MgONPs and then LED, and in all 3 experimental groups, it was significantly higher than control group (P < 0.05). Also, after 24 and 48 h, the density of ARS increased in all groups compared to the control group, and the highest density was observed in the MgONPs + LED and MgONPs groups. CONCLUSION: This research concluded that exposure to SCAPs, MgONPs, and LED irradiation has a significant effect on enhancing gene expression of odontogenic/osteogenic markers and increasing matrix mineralization.

Evaluation of cytotoxicity impacts of combined methylene blue-mediated photodynamic therapy and intracanal antibiotic medicaments on dental stem cells.

Root canal therapy is a predominant method for treatment of dental pulp and periapical diseases. Conventional methods such as mechanical instrumentations, chemical irrigation and intracanal medicaments pose a huge limitation to root canal disinfection as they kill bacteria and dental stem cells simultaneously. Therefore, much attention has been focused on finding more efficacious antibacterial methods that has no or negligible cytotoxicity for dental stem cells. Herein, we hypothesized that combining antibacterial medicaments with Antimicrobial photodynamic therapy (aPDT) and methylene blue (MB) as a photosensitizer would be effective in reducing death of dental pulp stem cells (DPSCs). To examine this, DPSCs were isolated from third molar teeth through enzymatic digestion. Isolated cells were cultured in αMEM and when reached adequate confluency, were used for further analysis. Cytotoxicity effect of different groups of MB, DAP, MB, LED and their combination on DPSCs was analyzed using MTT assay. DPSCs membrane integrity as a marker of live cells was assessed through measuring lipid peroxidation and lactate dehydrogenase (LDH) release into extracellular space. Results showed that the combination of LED, MB and TAP or aPDT, MB and DAP was more effective in reducing DPSCs death rate compared to TAP and DAP administration alone. Moreover, Malondialdehyde (MDA) and LDH levels were found to be decreased in cells exposed to combination treatment in comparison with single TAP or DAP therapy. Our study shows the promising perspectives of employing combined aPDT, MB and antibiotic medicaments for reduction of dental stem cell death.

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

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.

Association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography.

BACKGROUND: Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibular second molars on panoramic-like and axial views of cone-beam computed tomography (CBCT). METHODS: This cross-sectional study evaluated 1,231 CBCT scans of mandibular second molars obtained between October 2018 and February 2022 that were retrieved from the archives of a private radiology clinic. Panoramic-like images were reconstructed from the CBCT scans. The root morphology of mandibular second molars was classified on panoramic-like images as type 1, 2, 3, 4, or 5. The root pattern on axial CBCT images was classified into three types of single, double and C-shaped. The association of root morphology on panoramic-like and axial CBCT views was analyzed by the Chi-square test and Fisher's exact test at 0.05 level of significance. RESULTS: Of all, 62.7% of mandibular second molars were type 1; out of which, 97.3% had a double-root pattern on axial CBCT images. Also, 28.6% of them were type 2; of which, 92.6% had a double-root pattern. Moreover, 3.9% were type 3; of which, 47.9% had a C-shaped pattern; 0.9% were type 4, and 45.5% of them showed a single-root pattern; 3.8% were type 5 with 76.6% of them showing a single-root pattern. The prevalence of C-shaped canals was higher in females, and most C-shaped canals had a C3 pattern. CONCLUSION: Root morphology on panoramic-like CBCT views had a strong association with the root canal pattern on axial CBCT views. According to the results, mandibular second molars with a type 3 morphology on panoramic-like CBCT images are highly probable to have a C-shaped canal.

Effect of 810 nm Diode Laser Irradiation on the Time of Initiation and Depth of Anesthesia for Endodontic Treatment of Mandibular First Molars with Symptomatic Irreversible Pulpitis: A Clinical Trial.

Objective: In endodontic treatments, performing appropriate anesthesia in patients with irreversible pulpitis in mandibular molars may result in pain and severe problems. The irradiation of low-level lasers could be effective in this regard due to its anti-inflammatory and regenerative properties. This study aimed to assess the effect of 810 nm diode laser on the time of initiation and depth of anesthesia for endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Materials and methods: This randomized controlled clinical trial evaluated 60 patients requiring endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis and pain score ≥114 according to the Heft-Parker visual analog scale (HP-VAS). The teeth were randomized into two groups of diode laser and control. In the diode laser group, 810 nm diode laser with 300 mW power and 15 J/cm2 energy density was irradiated to the buccal surface of tooth crowns for 20 sec at 2 mm distance immediately before anesthesia administration. Laser in off mode was used in the control group. Inferior alveolar nerve block was then performed using 2% lidocaine with 1:80,000 epinephrine. After anesthetic injection, the mandibular first molar and canine teeth (control) were tested by an electric pulp tester every 2 min. Two consecutive negative responses to 80 mA indicated the initiation of anesthesia. HP-VAS forms were filled out by patients to assess their level of pain during the procedure. Data were analyzed by the Student's t and Chi-square tests, and analysis of variance (α = 0.05). Results: No remarkable difference was noted between the laser group and control groups in pain severity or anesthesia onset (p > 0.05). Conclusions: Low-level (810 nm) diode laser did not affect the time of initiation or depth of anesthesia in endodontic treatment of mandibular first molars with symptomatic irreversible pulpitis. Clinical trials registration: Iranian Registry of Clinical Trials (IRCT20181222042076N1).

The effects of melatonin on the viability and osteogenic/odontogenic differentiation of human stem cells from the apical papilla.

BACKGROUND: An experimental study was conducted to examine whether melatonin influences osteogenic/odontogenic differentiation of human stem cells derived from the apical papilla (hSCAPs). MATERIALS AND METHODS: In order to isolate hSCAPs, the undeveloped root of a third molar of a human tooth was used. Melatonin was administered to the experimental groups in an osteogenic medium. No treatment was administered to the control group. The methyl thiazolyl tetrazolium (MTT) assay was performed on days 1, 2, and 3 to assess cell viability (n = 8). A determination of odontogenic/osteogenic differentiation was accomplished using alkaline phosphatase (ALP) activity alizarin red staining (ARS) (n = 6), and the expression of osteogenic genes by real-time polymerase chain reaction (RT-PCR) (n = 3) on days 1, 2, and 7. Evaluation of the data was conducted using SPSS version 18. All experiments were conducted at least three times. The Mann Whitney U test, the ANOVA analysis, Tukey's test, and t-test was implemented to analyze the data (α = 0.05). RESULTS: After 24 h, 48 h, and 72 h, No significant difference was observed between the control group and the melatonin treatment group in terms of viability of hSCAPs. (from 1 up to 10 µg/ml) (P > 0.05). The assessment of ARS and ALP activity showed that melatonin treatment enhanced osteogenic differentiation of hSCAPs (P < 0.001). Melatonin treatment caused hSCAPs to show an increase of genes related to osteogenic/odontogenic differentiation. These genes included ALP, dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP-1), and bone sialoprotein (BSP) (P < 0.001). CONCLUSIONS: Melatonin treatment enhanced osteogenic/odontogenic differentiation of hSCAPs with a dose dependent effect on cell viability.

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.

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-1ß), 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-1ß was noted in the aspirin-treated group while an increase in ATL was observed (P < 0.001). There was no significant difference in the mediator scores before and after in the placebo-treated group (P > 0.05). CONCLUSION: Low-dose aspirin can influence the inflammatory process by reducing pro-inflammatory mediators such as PGE2 and IL-1ß, as well as increasing the pro-resolving mediators such as ATL. TRIAL REGISTRATION: IRCT20191211045702N1.

Effect of copper oxide nanoparticles and light-emitting diode irradiation on the cell viability and osteogenic/odontogenic differentiation of human stem cells from the apical papilla.

OBJECTIVES: This experimental study aimed to assess the effect of copper oxide nanoparticles (CuONPs) and light-emitting diode (LED) irradiation on the cell viability and osteogenic/odontogenic differentiation of human SCAPs. METHODS: After the culture of SCAPs, the effects of different concentrations of CuONPs on cell viability were evaluated by the methyl thiazolyl tetrazolium (MTT) assay after 24 and 48 h, and the optimal concentration was determined (n = 12). SCAPs were then divided into four groups based on the type of treatment: (I) no-treatment control group, (II) exposure to CuONPs, (III) LED irradiation (635 nm, 200 mW/cm2) for 30 s, and (IV) exposure to CuONPs combined with LED irradiation. CuONPs were synthesized by a green technique, which was based on reduction and simultaneous stability of copper ions by using the pomegranate peel extract. After treatments, the expression of osteogenic/odontogenic markers including dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), alkaline phosphatase (ALP), and dentin matrix acidic phosphoprotein 1 (DMP1) was evaluated in all four groups using quantitative real-time polymerase chain reaction (PCR) (n = 16). Also, osteogenic differentiation of SCAPs was evaluated qualitatively by alizarin red staining (ARS) to assess the matrix mineralization (n = 4). SPSS version 18 was used for data evaluation. The Kruskal-Wallis and Mann-Whitney tests were used to compare the groups. RESULTS: Exposure to 1 µg/mL CuONPs resulted in maximum viability of SCAPs. Concentrations of CuONPs over 10 µg/mL significantly decreased the viability of SCAPs. Real-time PCR showed that the expression of DMP1, BSP, ALP, and DSPP in CuONPs + LED and LED groups was significantly higher than that in CuONPs and control groups at both 24 and 48 h (P < 0.05). The density of ARS increased in all experimental groups after 24 h, and in CuONPs + LED and CuONPs groups after 48 h, compared to the control group. CONCLUSION: Addition of CuONPs and LED irradiation of SCAPs in the culture medium significantly enhanced their osteogenic/odontogenic differentiation.

Combination of Dental-Capping Agents with Low Level Laser Therapy Promotes Proliferation of Stem Cells from Apical Papilla.

Background: Direct pulp capping is a vital pulp therapy, which stimulates differentiation of stem cells from apical papilla (SCAPs). SCAPs have multipotential capacity to differentiate into types of cells, contributing to the regeneration of tissues. Objective: Considering the promising effects of dental-capping materials, we aim to investigate the effect of dental dressing materials combined with laser therapy on the percentage of SCAP viability and the consequent dental regeneration capacity. Methods: We collected two immature third molar teeth and isolated SCAPs through collagenase type I enzymatic activity. Isolated SCAPs were then cultured with Dulbecco's modified Eagle's medium and α-minimum essential medium enriched with 15% and 10% fetal bovine serum, respectively. After reaching 70-80% confluency, cells were seeded in a 96-well plate and then treated with mineral trioxide aggregate (MTA), enamel matrix derivative (EMD), biodentine, and low level laser therapy (LLLT) alone and in combination for 24, 48, and 168 h. After that, cell survival rate was assessed using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Results: We found that combination of MTA, EMD, and LLLT as well as that of biodentine, EMD, and LLLT could lead to significant increase of SCAP viability as compared with other treatment groups. Combination of MTA and biodentine with EMD could also show increased level of SCAP proliferation and viability. However, MTA and biodentine alone reduced SCAP survival rate in all time points. Conclusions: Our conclusion is that LLLT can serve as an enhancer of SCAP proliferation and differentiation rate when added to dental-capping agents such as MTA, EMD, and biodentine. Thus, LLLT combination with effective capping materials will serve as a promising option for dental tissue repair.

Effect of different intracanal posts and exposure parameters on detection of vertical root fractures by cone-beam computed tomography.

This study evaluated the effect of different amperage values and voxel sizes of two CBCT scanners on VRF detection in the presence of different intracanal posts. After post-space preparation, VRFs were induced in half of the samples of 20 maxillary premolars. Five different intracanal posts were passively placed in each root canal. Samples were scanned using CS 9300 and Cranex3D with two different voxel sizes and amperage setting in each unit. The diagnostic sensitivity, specificity and accuracy were compared using the Mann-Whitney and Kruskal-Wallis tests (α = 0.05). Changes in amperage and voxel size did not affect the detection of VRFs (p ⟩ 0.05). The VRF detection accuracy was the highest in fibreglass and the lowest in nickel-chromium group. Changes in amperage and voxel size within assessed values do not seem to influence the detection of VRF whereas different intracanal post-materials have significant effect on VRF detection.

Effects of CEM cement and emdogain on proliferation and differentiation of human stem cells from the apical papilla: a comparative in vitro study.

OBJECTIVES: This study compared the effects of calcium-enriched mixture (CEM) cement, Emdogain (EMD), and their combination (CEM/Emdogain) on the differentiation and proliferation of stem cells from the apical papilla (SCAPs). METHODS: In this in vitro, experimental study, SCAPs were isolated from two sound immature impacted third molars and cultured. After ensuring their stemness by detecting cell surface markers they were exposed to CEM cement, Emdogain, and CEM cement coated with Emdogain for 24 and 72 h. The control cells did not undergo any intervention. Cell viability [by methyl thiazolyl tetrazolium (MTT) assay], expression of odontogenic differentiation genes [by quantitative reverse-transcription polymerase chain reaction (qRT-PCR)], and alkaline phosphatase (ALP) activity (by ALP staining kit) were evaluated. Data were analyzed by one-way ANOVA, t-test, and Mann-Whitney test (α = 0.05). RESULTS: Cell viability in the CEM cement and CEM/Emdogain groups decreased compared with the control group at 72 h (P < 0.05). Expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP) genes, and ALP activity significantly increased in all three experimental groups compared with the control group at both 24 and 72 h. This increase was substantially more significant in CEM/Emdogain group (P > 0.05). The number of mineralized nodules significantly increased in all groups at 72 h, with a higher rate in the CEM/Emdogain group. CONCLUSION: All biomaterials increased the differentiation of SCAPs, expression of odontogenic differentiation genes, and ALP activity, but CEM/Emdogain was considerably more effective for this purpose.

Effect of diode low level laser and red light emitting diode irradiation on cell proliferation and osteogenic/odontogenic differentiation of stem cells from the apical papilla.

BACKGROUND: This experimental study aimed to assess the effect of irradiation of red light-emitting diode (LED) and Diode low-level laser (LLL) on osteogenic/odontogenic differentiation of stem cells from the apical papilla (SCAPs). MATERIALS AND METHODS: SCAPs were isolated from the human tooth root. The experimental groups were subjected to 4 J/cm2 diode low level laser and red LED irradiation in osteogenic medium. The control group did not receive any irradiation. Cell viability/proliferation of SCAPs was assessed by the methyl thiazolyl tetrazolium (MTT) assay on days 1 and 2 (n = 9). Osteogenic differentiation was evaluated by alizarin red staining (ARS) (n = 3), and expression of osteogenic genes by real-time polymerase chain reaction (RT-PCR) (n = 12) on days 1 and 2. SPSS version 18 was used for data evaluation. The Kruskal-Wallis and Mann-Whitney tests were used to compare the groups at each time point. RESULTS: The MTT assay showed no significant difference in cell viability/proliferation of SCAPs in the low level laser, red LED, and control groups at 24 or 48 h (P < 0.001). The ARS assessment showed that low level laser and red LED irradiation enhanced osteogenic differentiation of SCAPs. low level laser and red LED irradiation both induced over-expression of osteogenic/dentinogenic genes including alkaline phosphatase (ALP), dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP-1), and bone sialoprotein (BSP) in SCAPs. Up-regulation of genes was significantly greater in low level laser irradiation group than red LED group (P < 0.001). CONCLUSION: Diode low level laser irradiation with 4 J/cm2 energy density and red LED irradiation enhanced osteogenic differentiation of SCAPs without adversely affecting cell viability.

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.

Background: 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 comparison with Er:YAG laser (as a novel modality for root canal disinfection) on the adhesion of stem cells from the apical papilla (SCAPs) to dentin. Material and Methods: Forty dentin specimens were prepared and subjected to different treatments in 5 groups (n=8) of control, irrigation with EDTA for 1 minute, irrigation with MTAD for 5 minutes, irrigation with QMix for 5 minutes, and Er:YAG laser irradiation. SCAPs were isolated from third molar tooth buds that two-thirds of their roots had formed. The cells were cultured on dentin specimens for 3 days and were counted using scanning electron microscopy (SEM). Results: MTAD resulted in significantly lower adhesion of cells to dentin compared with other groups (P<0.05). All other modalities induced cell adhesion with no significant difference with each other (P>0.05). Conclusions: Despite many favorable properties, MTAD cannot serve as an optimal irrigant in endodontic regenerative procedures since it inhibits the adhesion of SCAPs to dentin and impairs an important step in tissue engineering. Key words:Endodontic Regeneration, Er-YAG laser, MTAD, QMix, EDTA, SCAP, stem cell adhesion.

Effect of biodentine coated with emdogain on proliferation and differentiation of human stem cells from the apical papilla.

BACKGROUND: This study assessed the effect of Biodentine coated with Emdogain (Biodentine/Emdogain) on proliferation and differentiation of human stem cells from the apical papilla (SCAPs). METHODS AND RESULTS: In this in vitro, experimental study, SCAPs were isolated from two immature impacted third molars and cultured. After ensuring the stemness of the cells by assessing the cell surface markers, they were exposed to Biodentine, Emdogain, and Biodentine/Emdogain for 24 and 72 h. The control cells did not receive any intervention. Cell viability was evaluated by the methyl thiazolyl tetrazolium assay. Expression of odontogenic differentiation genes was analyzed by the quantitative reverse transcription polymerase chain reaction. Alkaline phosphatase (ALP) activity was quantified by the respective kit. Data were analyzed by one-way ANOVA, t-test, and Mann-Whitney test (α = 0.05). Cell viability did not change after 24 h of exposure to biomaterials. At 72 h, the viability of the cells exposed to Biodentine and Biodentine/Emdogain decreased compared with the control group. The expression of dentin sialophosphoprotein, dentin matrix protein 1, and bone sialoprotein genes, and ALP activity significantly increased in all three experimental groups, compared with the control group at both 24 and 72 h; this increase was significantly greater in Biodentine/Emdogain group. The number of mineralized nodules significantly increased in all groups after 72 h with a greater rate in Biodentine/Emdogain group. CONCLUSIONS: All biomaterials increased the differentiation of SCAPs, expression of odontogenic genes, and ALP activity, but Biodentine/Emdogain was significantly more effective for this purpose.

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

Introduction: Dental pulp capping is a technique that is highly applicable in dental restorations. In this technique, a material is directly placed over the exposed pulp tissue, which promotes pulp healing and generates reparative dentin. Herein, we aimed to investigate the combined effect of different pulp capping agents, including mineral trioxide aggregate (MTA), Emdogain (EMD), calcium-enriched mixture (CEM), and low-level laser therapy (LLLT), on enhancing viability and proliferation of stem cells from apical papilla (SCAPs). Methods: SCAPs were isolated 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, the cells were seeded in a 96-well plate. Cell viability percent was assessed using the MTT assay after treatment with MTA, EMD, CEM and LLLT (λ=630 nm, 5 mW, 4 J/cm2 ) alone and in combination for 24, 48 and 168 hours. Results: Combination of MTA, CEM, EMD and LLLT resulted in significantly increased SCAPs viability as compared with other treatment groups. Increased SCAPs proliferation and viability were also observed in groups treated with the combination of MTA and CEM with EMD. However, the SCAPs survival rate in all defined time spans was reduced after treatment with MTA and CEM alone. Conclusion: LLLT can be a stimulator of SCAPs cell viability when applied in combination with dental capping agents such as MTA, EMD and CEM, providing a therapeutic option for stem cell-based dental regeneration.

Management of Dental School During the COVID-19 Pandemic: Application of Intervention Mapping.

Background: Coronavirus Diesease-2019 (COVID-19) outbreak has led to the suspension of the activities of dental schools. Therefore, reorganizing clinical settings and supporting services as quickly as possible has received much attention to reopen dental schools. The present study aimed to evaluate the applicability of the Intervention Mapping (IM) approach for designing, implementing, and evaluating an intervention program to prevent and control COVID-19 in dental schools. Methods: Following the IM protocol, six steps were completed in the planning and development of an intervention, targeting, and management of Dental School during the COVID-19 pandemic. Results: The information obtained from the needs assessment revealed that the COVID-19 outbreak prevention was associated with the use of personal protective equipment by all target groups, infection control measures taken in the environment, preparation of the environment and equipment, changes in the treatment plan according to the COVID-19 pandemic, changing the admission process of patients, and reduction of attendance of target groups in the school are linked with. In this study, determinant factors affecting the COVID-19 prevention at the individual level were identified based on the Protection Motivation Theory (PMT). In this program, various methods, such as presentation of information, modeling role, and persuasion measures, were utilized and the practical programs included educational films and group discussions implemented. Conclusions: Our findings indicated that intervention in dental environments on the basis of the IM process can develop a comprehensive and structured program in the dental school and hence can reduce the risk of the COVID-19 infection.

Cone-beam computed tomographic analysis of apical transportation and centering ratio of ProTaper and XP-endo Shaper NiTi rotary systems in curved canals: an in vitro study.

BACKGROUND: Cleaning and shaping of the root canal system is an important step of endodontic treatment. Canal transportation is a common procedural error in preparation of curved canals. This study aimed to compare the canal transportation and centering ratio of two rotary files in curved canals using cone-beam computed tomography (CBCT). METHODS: Forty-four extracted human mandibular first molars with mature apices and 10° to 30° apical curvature were selected. The samples were randomly divided into two groups (n = 22) with similar curvature. The canals were prepared with ProTaper and XP-endo Shaper file systems according to the manufacturers' instructions. The CBCT images were obtained using Cranex 3D CBCT scanner before and after root canal preparation, and canal transportation and centering ratio of the files at 3, 4 and 5 mm levels from the apex were calculated. Data were compared between the two groups using independent t-test at 0.05 level of significance. RESULTS: The ProTaper Universal caused greater canal transportation and had lower centering ratio than XP-endo Shaper in both mesiodistal and buccolingual directions at all levels from the apex. The difference between the two groups regarding canal transportation was significant at all levels from the apex in buccolingual direction (P < 0.05) except for 3 mm from the apex (P > 0.05). The difference between the two groups regarding centering ratio was not significant (P > 0.05) in mesiodistal direction at all levels except for 4 mm from the apex (P < 0.05). CONCLUSION: The ProTaper Universal causes greater canal transportation in both buccolingual and mesiodistal directions than XP-endo Shaper.