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.

Synthesis and characterization of hydroxyapatite nanoparticles and their effects on remineralization of demineralized enamel in the presence of Er,Cr: YSGG laser irradiation.

BACKGROUND: This study aims to synthesize and characterize hydroxyapatite nanoparticles (nano-HA) and evaluate their effects on the remineralization of demineralized enamel in the presence to Er,CR: YSGG laser irradiation. MATERIALS AND METHODS: Enamel specimens from 44 human molars were divided into four groups: control, demineralized enamel, demineralized enamel treated with nano-HA, and demineralized enamel treated with nano-HA followed by Er,Cr:YSGG laser irradiation (0.5, 20 Hz, 60 µs, 20 s). Vickers microhardness test was used to evaluate the enamel surface hardness. The morphology and chemistry of enamel surfaces were assessed using scanning electron microscopy (SEM) and Raman spectroscopy, respectively. RESULT: The result of this study showed that the application of Er,CR: YSGG laser irradiation to demineralized enamel treated with nano-HA had the highest impact on its microhardness. CONCLUSION: ER,CR: YSGG laser irradiation promotes enamel remineralization after treatment with nano HA.

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.

Effect of sodium fluoride varnish, Gluma, and Er,Cr:YSGG laser in dentin hypersensitivity treatment: a 6-month clinical trial.

Dentinal hypersensitivity (DH) is a common clinical condition usually associated with exposed dentinal surfaces. The aim of this study was to study the effect of sodium fluoride varnish, Gluma, and Er,Cr:YSGG laser, in the dentin hypersensitivity treatment. One hundred sixty-five teeth with dentin hypersensitivity in 55 patients were involved in this study. Teeth are divided into five groups based on the received treatment (n = 33): G group: Gluma; F group: sodium fluoride varnish (5%); L group: Er,Cr:YSGG laser (wavelength 2780 nm, frequency 20 Hz, power 0.25 W, energy density 44.3 J/cm2, and pulse width of 150 µs at distance of 1 mm for 30 s) which was followed by Er,Cr:YSGG laser; GL group: Gluma + laser; VL group: both sodium fluoride varnish and Gluma, which are common treatments for hypersensitivity, were selected as control groups. The treatment was performed in one session, and the sensitivity to air spray conditioning was recorded after the treatment, at 15 min, 1 week, 1 month, and 6 months as the VAS. Statistical analysis was performed using SPSS Ver. 21 software. One-way ANOVA was used to compare the VAS between all treatment groups at each time-point. One-way repeated measurements ANOVA (RM-ANOVA) and two-way-repeated measurements ANOVA (RM-ANOVA) were used to compare the hypersensitivity of each group and sensitivity of all treatment groups, respectively. Tukey post hoc test was used to compare the groups pairwise. The hypersensitivity between different groups at before and 15 min after the treatment was not significantly different (P = 0.063). The hypersensitivity of all studied groups was decreased after the treatment. The Er,Cr:YSGG laser, alone or in combination with Gluma, in 1 week, 1 month, and 6 month follow-ups, had significantly reduced the hypersensitivity instead of sodium fluoride varnish. All treatments significantly reduced the dentin hypersensitivity up to 6 months. Er,Cr:YSGG laser alone or in combination with Gluma was more effective than sodium fluoride varnish; however, it was not significantly different from other treatments. In a 6-month follow-up of dentine hypersensitivity treatment, Gluma had a significantly higher effect than sodium fluoride. Trial registration: IRCT20190422043343N1. Registered 19 July 2019.

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.

Effect of 940 nm laser diode irradiation prior to bonding procedure on postoperative sensitivity following class II composite restorations: a split-mouth randomized clinical trial.

The aim of this study was to evaluate the effect of 940 nm laser diode on class II composite cavities prior to bonding and restoration process on the postoperative sensitivity (POS). Thirty patients with two bilateral premolars with mesio or disto-occlusal carious lesions were evaluated. In each patient, the teeth were randomly divided into the control and laser groups. After cavity preparation and isolation and before the bonding process, the laser group was subjected to 940 nm irradiation (Epic 10, Biolase, USA) by 400 µ tip continuously at 100 mW with 398 J/cm2 energy density of tip, which was applied for 5 s at a distance of 2 mm on the axial wall of the cavity. In the control group, irradiation was performed by using the aiming beam. Access cavity was then restored with a composite resin. Cold sensitivity was measured using a cold spray application on the middle third of teeth buccal surface at baseline (before the intervention), 1, 14, and 30 days after the restoration by visual analog scale (VAS) criteria. The mean Friedman and Wilcoxon signed-rank tests were used for data analysis. It was shown that in both laser and control groups, the VAS was significantly decreased at all times compared to the baseline (p ≤ 0.05). There was no statistically significant difference between the mean VAS of two groups at baseline and first day (p ≤ 0.05), but at 14 and 30 days after the intervention, it was significantly lower in the laser group (p ≤ 0.05). The results of this study demonstrated that the cavity pretreatment with laser diode (940 nm) effectively reduces the postoperative sensitivity in class II composite restorations.

Effect of carbon dioxide laser irradiation on enamel surface microhardness around orthodontic brackets.

INTRODUCTION: In this study, we aimed to determine the effect of carbon dioxide laser irradiation on enamel surface microhardness. METHODS: In this single-blind interventional clinical trial, 16 patients needing at least 2 premolars extracted for orthodontic purposes participated. In each subject, 1 premolar was treated with the carbon dioxide laser (beam diameter, 0.2 mm; power, 0.7 W); the other was exposed to a visible guiding light as the control. A t-loop was ligated to the bonded brackets to increase caries risk. After at least 2 months, the teeth were extracted, and the surface microhardness was measured. Scanning electron microscope evaluation was performed on 1 sample from each group. Normal distribution of the data was assessed by the Kolmogorov-Smirnov and Shapiro-Wilks tests. Mean microhardness values of the 2 groups were compared using paired t tests. RESULTS: The data had normal distributions. Means and standard deviations of the microhardness in the laser-treated and control groups were 301.81 ± 94.29 and 183.9 ± 72.08 Vickers hardness numbers, respectively; this was different significantly (P <0.001). Scanning electron microscopy showed the enamel surface melting in the laser-treated specimens. CONCLUSIONS: Carbon dioxide laser treatment results in higher enamel surface microhardness around orthodontic brackets. Patients at high risk of caries might benefit from this intervention. Exact control of the laser irradiation parameters is recommended.

Correction: Relationship between Salivary Alkaline Phosphatase Enzyme Activity and The Concentrations of Salivary Calcium and Phosphate Ions.

In this article published in Cell J, Vol 17, No 1, 2015, on pages 159-162, the authors found that the affiliation of second author in address 2 was missed during the formatting of the paper. Therefore, we corrected it. The authors would like to apologize for any inconvenience.

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.

Submandibular abscess due to an infected keratocystic odontogenic tumor associated with simultaneous occurrence of a traumatic bone cyst: a rare case report.

AIM: The aim of this report is to introduce a rare case in which an infected keratocystic odontogenic tumor (KCOT) was initially diagnosed and treated as a dentoalveolar abscess. BACKGROUND: Keratocystic odontogenic tumor (KCOT) is a benign neoplasm that can be secondarily infected. However, cervical soft tissue abscess formation as a result of an infected odontogenic cyst or tumor is a rare condition few of which have only been described in the existing literature. Also, there has been a single report regarding the coincidence of a traumatic bone cyst and a keratocytic odontogenic tumor to date. CASE REPORT: The patient was a 29-year-old male, complaining of fever, pain and swelling in the left submandibular region. The panoramic radiography showed a well-defined and partially corticated radiolucency between the roots of the second and third left mandibular molars. In addition, a well-corticated radiolucent lesion was incidentally found on the right side of the mandible, which, following surgical exploration, was diagnosed as a traumatic bone cyst. CONCLUSION: In the present report, an infected KCOT manifested as a cervical abscess, coincided with a traumatic bone cyst. CLINICAL SIGNIFICANCE: From the clinical point of view, it is of paramount significance to prevent misdiagnosis of similar presentations as pulp and periapical lesions, which may lead to mistreatment and thus complications.