Comparison of bond strength of self-adhesive and self-etch or total-etch resin cement to zirconia: A systematic review and meta-analysis.

The aim of this study was to systematically compare the bond strength of self-adhesive and self-etch or total-etch resin cement to zirconia. The PubMed, ISI (all), and Scopus databases were searched for the selected keywords up to November 1, 2021, without date or language restrictions. In vitro studies comparing the bond strength of self-adhesive and self-etch or total-etch resin cement to zirconia were eligible for inclusion in the study. The selected articles were divided into four groups based on the type of resin cement and the storage time. Statistical analysis was performed using the Biostat Comprehensive Meta-Analysis Software version 2 (α = 0.05). The effect of conventional cement ( Glass Ionomer (GI), Resin Modified Glass Ionomer (RMGI) and zinc phosphate) was analyzed using descriptive analysis. The initial search yielded 376 articles, of which 26 were selected after a methodological assessment. Two reviewers independently extracted data and assessed the risk of bias. The results showed that the immediate or delay bond strength of the self-adhesive resin cement to zirconia has no significant difference with the bond strength of self-etch resin cement to zirconia. The immediate and delay bond strength of total-etch cement-zirconia was significantly lower than that of self-adhesive cement-zirconia (P = 0.00). A descriptive analysis of the selected articles showed that the bond strength of self-adhesive resin cement to zirconia was significantly higher than total-etch cement. The results of the meta-analysis showed that both self-adhesive and self-etch resin cement (if applied according to their manufacturer's instruction) are suitable for bonding to zirconia.

Evaluation of the Effect of Maternal Education on Toddler Dental Plaque Removal Based on a Health Belief Model.

Objectives: The objective of this study was to investigate the impact of an educational intervention, guided by the Health Belief Model (HBM), on promoting preventive behaviors among mothers to combat early childhood caries (ECC) in toddlers aged 12 to 18 months. Materials and Methods: This single-blind interventional study evaluated 92 toddlers between 12 to 18 months and their mothers, who were selected by stratified random sampling. Data regarding demographic and nutritional factors were collected using a questionnaire. The dental status of children was evaluated by clinical examination and measuring the plaque index (PI) of maxillary central incisors and the dmfs index. A pamphlet designed according to the HBM was used for oral hygiene instruction in both the intervention and control groups. All of the mothers in the intervention group received a music file to listen to when brushing their children's teeth. Data were analyzed using chi-square, Fisher exact, Mann-Whitney, and Wilcoxson tests. P<0.05 was considered significant. Results: No significant correlation was noted between the daily frequency of sugary substance intake and primary PI in the intervention or control group with/without dental plaque (P>0.05). In the intervention group, PI significantly decreased after the intervention compared to baseline (P<0.001). However, there was no significant change in PI after the intervention in the control group compared with baseline (P=0.1). Conclusion: The findings indicate that a combination of educational intervention and incentives, such as using age-appropriate music for toddlers, can significantly enhance mothers' effectiveness in removing dental plaque.

Reducing pain and discomfort associated with rubber dam clamp placement in children and adolescents: a systematic review and meta-analysis of effectiveness.

BACKGROUND: The application of rubber dams is a widely accepted method of tooth isolation in dental practice. Placement of the rubber dam clamp might be associated with levels of pain and discomfort, especially in younger patients. The purpose of the present systematic review is to evaluate the efficacy of the methods for reducing pain and discomfort associated with rubber dam clamp placement in children and adolescents. MATERIALS AND METHODS: English-language literature from inception until September 6th, 2022 was searched in MEDLINE (via PubMed), SCOPUS, Web of Science, Cochrane, EMBASE, and ProQuest Dissertations & Theses Database Global for articles. Randomized controlled trials (RCTs) comparing methods of reducing the pain and/or discomfort associated with rubber dam clamp placement in children and adolescents were retrieved. Risk of bias assessment was performed using a Cochrane risk of bias-2 (RoB-2) risk assessment tool and the certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) evidence profile. Studies were summarized and pooled estimates of pain intensity scores and incidence of pain were calculated. The meta-analysis was conducted in the following groups according to type of interventions (LA, audiovisual (AV) distraction, behavior management (BM), electronic dental anesthesia (EDA), mandibular infiltration, inferior alveolar nerve block (IANB), TA), outcome (intensity or incidence of pain), and assessment tool (face - legs - activity - cry - consolability (FLACC), color scale, sounds - motor - ocular changes, and faces pain scale (FPS)): (a) pain intensity using (LA + AV) vs (LA + BM), (b) pain intensity using EDA vs LA (c) presence or absence of pain using EDA vs LA (d) presence or absence of pain using mandibular infiltration vs IANB (e) Comparing pain intensity using TA vs placebo (f) Presence or absence of pain using TA vs placebo. Meta-analysis was conducted using StataMP software, version 17.0 (StataCorp, College Station, Texas). Restricted maximum-likelihood random effect model (REML), Mean difference (MD) with 95% confidence interval, and log odds ratio (OR) with 95% CI were calculated were calculated. RESULTS: Initially, 1452 articles were retrieved. Sixteen RCTs were finally included for reviewing and summarizing. Nine articles with a total of 867 patients were included for quantitative meta-analysis. The differences in pain intensity scores were not significant in any comparison groups (group a: [MD = -0.04 (95% CI = - 0.56, 0.47), P = 0.87, I2 = 0.00%], group b: [MD = 0.25 (95% CI = -0.08, 0.58), P = 0.14, I2 = 0.00%], group c [MD = -0.48 (95% CI = -1.41, 0.45), P = 0.31, I 2 = 0.00%], group d: [MD = -0.67 (95% CI = -3.17, 1.83), P = 0.60, I 2 = 0.00%], group e: [MD = -0.46 (95% CI = -l.08, 0.15), P = 0.14, I 2 = 90.67%], and group f: [MD = 0.61 (95% CI = -0.01, 1.23), P = 0.06, I 2 = 41.20%]. Eight studies were judged as having some concern for risk of bias and the remaining studies were considered as low risk for bias. The certainty of evidence was considered medium for all comparison groups. DISCUSSION: In the present meta-analysis, a considerable difference was obtained between the included studies regarding intervention methods and pain assessment tools and the analysis was performed in groups with small numbers of the studies. Owing to the mentioned variabilities and the small number of studies, the results of the analysis should be interpreted with caution. The indistinguishability of the manifestations of pain/discomfort from fear/anxiety, particularly in children, should also be considered while using the results of the present study. Within the limitations of the current study, no significant differences were found between the proposed methods for reducing pain and discomfort associated with rubber dam clamp placement in children and adolescents. A larger number of more homogenous studies regarding intervention methods and pain assessment tools need to be conducted in order to draw stronger conclusions. TRIAL REGISTRATION: This study was registered in PROSPERO (ID number: CRD42021274835) and research deputy of Mashhad University of Medical Sciences with ID number 4000838 ( https://research.mums.ac.ir/ ).

Food insecurity and dental caries prevalence in children and adolescents: A systematic review and meta-analysis.

BACKGROUND: Food insecurity (FI) is associated with dietary practices, which can act as a risk factor for dental caries. AIM: This study aimed to investigate the relationship between FI and dental caries prevalence in children and adolescents. DESIGN: MEDLINE (via PubMed), EMBASE, SCOPUS, ISI web of knowledge, Cochrane, and ProQuest Dissertations & Theses Global database (up to April 19, 2022) as well as reference lists were searched. Eligible studies compared dental caries prevalence in food-secure and food-insecure individuals younger than 19 years. Two independent reviewers performed study selection, data extraction, and risk of bias assessment using a modified Newcastle-Ottawa Scale. Meta-analysis was performed, and the pooled odds ratio (OR) was calculated at 95% confidence interval (95% CI). RESULTS: Among the 1350 retrieved records, 10 cross-sectional reports were selected for systematic review. Six studies involving 8631 participants were included in the meta-analysis. More than half of the reports were published within the period 2019-2021. All studies except one were judged as low risk of bias. Overall, the prevalence of dental caries was greater among the food-insecure children and adolescents (OR: 2.01, 95% CI: 1.52-2.65, p < .001, I2 : 73.5%). Similarly, all three categories of FI were significantly associated with caries experience (marginal FI: OR: 1.88, 95% CI: 1.56-2.27, p < .001, I2 : 0.0%; low FI: OR: 2.42, 95% CI: 1.42-4.14, p = .001, I2 : 74.4%; very low FI: OR: 2.37, 95% CI: 1.88-3.00, p < .001, I2 : 0.0%). CONCLUSION: The results showed a significant association between FI status and dental caries in both childhood and adolescence; however, there was a lack of longitudinal studies for a better understanding of this association. Health policies leading to reduction in FI may also aim to reduce dental caries.

Investigating the attenuating effect of telmisartan against radiation-induced intestinal injury using 18F-FDG micro-PET imaging.

BACKGROUND AND OBJECTIVE: This study was aimed to investigate the ability of 18F-Fluro-deoxy-glucose (18F-FDG)-based micro-positron emission tomography (microPET) imaging to evaluate the efficacy of telmisartan, a highly selective angiotensin II receptor antagonist (ARA), in intestinal tissue recovery process after in vivo irradiation. METHODS: Male Balb/c mice were randomly divided into four groups of control, telmisartan, irradiation, and telmisartan + irradiation. A solution of telmisartan in phosphate-buffered saline (PBS) was administered orally at 12 mg/kg body weight for seven consecutive days prior to whole body exposing to a single sub-lethal dose of 5 Gy X-rays. The mice were imaged using 18F-FDG microPET at 9 and 30 days post-irradiation. The 18F-FDG uptake in jejunum was determined according to the mean standardized uptake value (SUVmean) index. Tissues were also processed in similar time points for histological analysis. RESULTS: The 18F-FDG microPET imaging confirmed the efficacy of telmisartan as a potent attenuating agent for ionizing radiation-induced injury of intestine in mice model. The results were also in line with the histological analysis indicating that pretreatment with telmisartan reduced damage to the villi, crypts, and intestinal mucosa compared with irradiated and non-treated group from day 9 to 30 after irradiation. CONCLUSION: The results revealed that 18F-FDG microPET imaging could be a good candidate to replace time-consuming and invasive biological techniques for screening of radioprotective agents. These findings were also confirmed by histological examinations which indicated that telmisartan can effectively attenuates radiation injury caused by ionizing-irradiation.

Comparison of the Success Rate of Filled and Unfilled Resin-Based Fissure Sealants: A Systematic Review and Meta-Analysis.

Objectives: Incorporation of fillers might improve the physical properties of sealants. This systematic review and meta-analysis evaluated the retention and caries development rate of filled and unfilled fissure sealants. Materials and Methods: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The PubMed, Scopus, Embase, Cochrane Database of Systematic Reviews, and ISI Web of Knowledge were searched until October 24, 2019. The risk of bias (ROB) was assessed for the included studies based on the Cochrane collaboration common scheme for bias, and the meta-analysis was performed through a random effects model. Results: The search resulted in 6,336 unrepeated relevant studies. After the title, abstract and full-text screening, 19 studies with 26 comparing groups were finally included in this systematic review and meta-analysis. According to the included studies, both retention rate and caries development in filled and unfilled resin-based sealants did not significantly differ within 2 years of follow-up. Conclusion: Since there was no significant difference in the retention rate and caries development between filled and unfilled sealants, it seems that the final decision should be made uniquely for each patient according to the type of fissure, patient's age, habits, etc.

3D in vivo dosimetry of HDR gynecological brachytherapy using micro silica bead TLDs.

PURPOSE: This study aimed to evaluate the feasibility of defining an in vivo dosimetry (IVD) protocol as a patient-specific quality assurance (PSQA) using the bead thermoluminescent dosimeters (TLDs) for point and 3D IVD during brachytherapy (BT) of gynecological (GYN) cancer using 60 Co high-dose-rate (HDR) source. METHODS: The 3D in vivo absorbed dose verification within the rectum and bladder as organs-at-risk was performed by bead TLDs for 30 GYN cancer patients. For rectal wall dosimetry, 80 TLDs were placed in axial arrangements around a rectal tube covered with a layer of gel. Ten beads were placed inside the Foley catheter to get the bladder-absorbed dose. Beads TLDs were localized and defined as control points in the treatment planning system (TPS) using CT images of the patients. Patients were planned and treated using the routine BT protocol. The experimentally obtained absorbed dose map of the rectal wall and the point dose of the bladder were compared to the TPSs predicted absorbed dose at these control points. RESULTS: Relative difference between TPS and TLDs results were -8.3% ± 19.5% and -7.2% ± 14.6% (1SD) for rectum- and bladder-absorbed dose, respectively. Gamma analysis was used to compare the calculated with the measured absorbed dose maps. Mean gamma passing rates of 84.1%, 90.8%, and 92.5% using the criteria of 3%/2 mm, 3%/3 mm, and 4%/2 mm were obtained, respectively. Eventually, a "considering level" of at least 85% as pass rate with 4%/2-mm criteria was recommended. CONCLUSIONS: A 3D IVD protocol employing bead TLDs was presented to measure absorbed doses delivered to the rectum and bladder during GYN HDR-BT as a reliable PSQA method. 3D rectal absorbed dose measurements were performed. Differences between experimentally measured and planned absorbed dose maps were presented in the form of a gamma index, which may be used as a warning for corrective action.

Histopathological Evaluation of Protective Effect of Telmisartan against Radiation-Induced Bone Marrow Injury.

Background: Radiation-induced hematopoietic suppression and myelotoxicity can occur due to the nuclear accidents, occupational irradiation and therapeutic interventions. Bone marrow dysfunction has always been one of the most important causes of morbidity and mortality after ionizing irradiation. Objective: This study aims to investigate the protective effect of telmisartan against radiation-induced bone marrow injuries in a Balb/c mouse model. Material and Methods: In this experimental study, male Balb/c mice were divided into four groups as follow: group 1: mice received phosphate buffered saline (PBS) without irradiation, group 2: mice received a solution of telmisartan in PBS without irradiation, group 3: mice received PBS with irradiation, and group 4: mice received a solution of telmisartan in PBS with irradiation. A solution of telmisartan was prepared and administered orally at 12 mg/kg body weight for seven consecutive days prior to whole body exposing to a single sub-lethal dose of 5 Gy X-rays. Protection of bone marrow against radiation induced damage was investigated by Hematoxylin-Eosin (HE) staining assay at 3, 9, 15 and 30 days after irradiation. Results: Histopathological analysis indicated that administration of telmisartan reduced X-radiation-induced damage and improved bone marrow histology. The number of different cell types in bone marrow, including polymorphonuclear /mononuclear cells and megakaryocytes significantly increased in telmisartan treated group compared to the only irradiated group at all-time points. Conclusion: The results of the present study demonstrated an efficient radioprotective effect of telmisartan in mouse bone marrow against sub-lethal X-irradiation.

Modulation of Radiation-Induced NADPH Oxidases in Rat's Heart Tissues by Melatonin.

BACKGROUND: Experimental studies have shown that infiltration of inflammatory cells as well as upregulation of some cytokines play a central role in the development of late effects of ionizing radiation in heart tissues. Evidences have shown that an increased level of TGF-ß has a direct correlation with late effects of exposure to ionizing radiation such as chronic oxidative stress and fibrosis. Recent studies have shown that TGF-ß, through upregulation of pro-oxidant enzymes such as NOX2 and NOX4, promotes continuous ROS production and accumulation of fibrosis. OBJECTIVE: In present study, we aimed to evaluate the expression of NOX2 and NOX4 signaling pathways as well as possible modulatory effects of melatonin on the expression of these genes. MATERIAL AND METHODS: In this experimental study, four groups of 20 rats (5 in each) were used as follows; G1: control; G2: melatonin; G3: radiation; G4: radiation + melatonin. 100 mg/kg of melatonin was administrated before irradiation of heart tissues with 15 Gy gamma rays. 10 weeks after irradiation, heart tissues were collected for real-time Polymerase chain reaction (PCR). RESULTS: Results showed a significant increase in the expression of TGF-ß, Smad2, NF-kB, NOX2 and NOX4. The upregulation of NOX2 was more obvious by 20-fold compared to other genes. Except for TGF-ß, melatonin could attenuate the expression of other genes. CONCLUSION: This study indicated that exposure of rat's heart tissues to radiation leads to upregulation of TGF-ß-NOX4 and TGF-ß-NOX2 pathways. Melatonin, through modulation of these genes, may be able to alleviate radiation-induced chronic oxidative stress and subsequent consequences.

Vasoactive Peptides: Role in COVID-19 Pathogenesis and Potential Use as Biomarkers and Therapeutic Targets.

BACKGROUND: The ongoing outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as the latest threat to global health, causes overwhelming effects for the public healthcare systems worldwide. Of note, in addition to the respiratory complications, some patients with coronavirus disease 2019 (COVID-19) also develop serious cardiovascular injuries. Vasoactive peptides play an important role in a wide range of physiological and pathological conditions. AIM: With the urgent need for exploring the specific therapeutic targets and biomarkers for the emerging COVID-19, the general aim of this review is to discuss the potentials of the vasoactive peptides including Angiotensin II (Ang II), vasoactive intestinal peptide (VIP), endothelin-1 (ET-1), calcitonin gene-related peptide (CGRP), natriuretic peptides, substance P (SP) and bradykinin (BK) as therapeutic targets and/or prognostic indicators for the COVID-19 pandemic. CONCLUSION: Based on various observations some authors conclude that the assessment of vasoactive peptides shall be considered a routine part of COVID-19 patient monitoring, and they can serve as potential therapeutic targets for the disease management.

Management of primary molars with irreversible pulpitis employing tampon pulpotomy: Report of three cases with 34-month mean follow-up.

This study suggests that tampon-based coronal pulpotomy using a calcium silicate-based biomaterial can be a reliable approach for the treatment of vital primary molars with irreversible pulpitis.

Apigenin Enhanced Radiation-Induced Apoptosis/Necrosis by Sensitization of LNCaP Prostate Cancer Cells to 6 MV Photon Beams.

OBJECTIVE: Whereas prostate cancer (PrCa) may be unresponsive or moderately responsive to radiation therapy (RT)- most common modality for treatment of PrCa- patients must receive a high dose of RT In order to achieve appropriate tumour control. However, this increase in radiation dose may lead to severe adverse effects in normal tissues. Sensitization of PrCa to radiation provides an alternate approach to improve the therapeutic efficacy of RT. This study aims to assess the radiosensitisation effect of apigenin (Api) on a prostate cancer cell line (LNCaP). MATERIALS AND METHODS: In this experimental study, LNCaP cells were treated with 0-80 µM Api to investigate its effect on LNCaP cell viability and determine its half-maximal inhibitory concentration (IC50). Next, the cells were divided into four groups: i. Control, ii. Cells treated with the IC50 concentration of Api, iii. Cells treated with 2 Gy ionizing radiation (IR), and cells co-treated with Api and IR. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, real-time polymerase chain reaction (PCR), and an Annexin V-FITC/PI assay were performed to assess cell survival, Bax and Bcl-2 expressions, and presence of apoptosis and necrosis. RESULTS: Api inhibited cell survival in a dose-dependent, but not time-dependent manner. Cells treated with Api had increased amounts of early apoptosis, late apoptosis, and secondary necrosis compared to the control group. This group also had decreased Bcl-2 gene expression and up-regulated Bax gene expression. Co-treatment with Api and IR significantly inhibited cell survival, and increased early apoptosis, late apoptosis and secondary necrosis compared to the other groups. There was a significant decrease in Bcl-2 gene expression along with up-regulation of Bax gene expression, and Bax/Bcl-2 ratio changes that favoured apoptosis. CONCLUSION: Api inhibited PrCa cell survival and induced apoptosis as a single agent. In addition, Api significantly sensitized the LNCaP cells to IR and enhanced radiation-induced apoptosis.

The inhibitory effect of melatonin on the proliferation of irradiated A549 cell line.

BACKGROUND: Lung cancer is the leading cause of cancer-related deaths worldwide. The high resistance of this type of cancer to radiotherapy and chemotherapy is the greatest challenge for the complete eradication of cancer cells. Although the combination of chemotherapeutic agents has some promising results, severe side effects may limit the received tumor dose. The current study aimed at evaluating the possible synergic effect of melatonin on radiation-induced apoptosis and cell proliferation inhibition. MATERIALS AND METHODS: A549 cells were incubated with melatonin or vehicle and then irradiated with a single dose of 0, 0.5, 2, or 8 Gy X-rays. The cells were incubated with 1 nM of melatonin or vehicle for 1 week and then treated with 1 mM of melatonin or vehicle 1 h before irradiation. Cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and apoptosis was assessed using flowcytometry detection of annexin V. RESULTS: Irradiation of the cells with different X-ray doses had no significant impact on MTT results. However, the administration of 1 mM of melatonin 1 h before irradiation significantly reduced the cell proliferation. Nonetheless, there was no significant difference between this treatment group and 1 mM melatonin group. Moreover, the administration of melatonin in combination with irradiation did not show any significant effects on radiation-induced apoptosis. CONCLUSION: The current study results indicated that the treatment of A549 cells with melatonin could suppress cell proliferation, whereas it did not mediate the induction of apoptosis.

The radioprotective effect of melatonin against radiation-induced DNA double-strand breaks in radiology.

OBJECTIVE: The objective of this study is to observe the effect of 100-mg melatonin in reducing the levels of double-strand breaks (DSB) induced by 10 mGy and 100 mGy X-ray in peripheral lymphocyte applying H2AX immunofluorescence microscopy and comparing the different efficacies of melatonin ingestion 1 and 2 h before irradiation. MATERIALS AND METHODS: Informed consent was obtained from five healthy males, nonathlete, and nonsmoking human volunteers aged between 25 and 35 years. Each volunteer was given a single oral dose of 100 mg melatonin at 9 a.m. Blood samples were collected in vacutainer tubes (without any preservative to separate the serum, and with heparin as an anticoagulant for separating leukocytes for in vitro exposure to gamma radiation) 5-10 min before then 1 and 2 h after melatonin ingestion. Afterward, each sample was subdivided into nonirradiated and irradiated groups (10 mGy and 100 mGy). After irradiation, lymphocytes of samples were separated. The isolated lymphocytes in each group were permeabilized for DSB assessment and stained against the phosphorylated histone variant γH2AX. RESULTS: Melatonin ingestion 1 and 2 h before irradiation caused a significant reduction in γH2AX foci. Results further indicate that the change in ingestion of melatonin from 1 to 2 h before exposure had no significant effect. In addition, melatonin administration showed no side effects. CONCLUSION: The present study showed that melatonin will prove effective in radioprotection against ionizing radiation (IR)-induced DNA damage in human lymphocytes. Our results suggest ingestion of 100-mg melatonin by patients before exposure to IR in radiology.

Development of a novel and low-cost anthropomorphic pelvis phantom for 3D dosimetry in radiotherapy.

PURPOSE: The aim of this study was to construct a low-cost, anthropomorphic, and 3D-printed pelvis phantom and evaluate the feasibility of its use to perform 3D dosimetry with commercially available bead thermoluminescent dosimeters (TLDs). MATERIAL AND METHODS: A novel anthropomorphic female phantom was developed with all relevant pelvic organs to position the bead TLDs. Organs were 3D-printed using acrylonitrile butadiene styrene. Phantom components were confirmed to have mass density and computed tomography (CT) numbers similar to relevant tissues. To find out clinically required spatial resolution of beads to cause no perturbation effect, TLDs were positioned with 2.5, 5, and 7.5 mm spacing on the surface of syringe. After taking a CT scan and creating a 4-field conformal radiotherapy plan, 3 dose planes were extracted from the treatment planning system (TPS) at different depths. By using a 2D-gamma analysis, the TPS reports were compared with and without the presence of beads. Moreover, the bead TLDs were placed on the organs' surfaces of the pelvis phantom and exposed to high-dose-rate (HDR) 60Co source. TLDs' readouts were compared with the TPS calculated doses, and dose surface histograms (DSHs) of organs were plotted. RESULTS: 3D-printed phantom organs agreed well with body tissues regarding both their design and radiation properties. Furthermore, the 2D-gamma analysis on the syringe showed more than 99% points passed 3%- and 3-mm criteria at different depths. By calculating the integral dose of DSHs, the percentage differences were -1.5%, 2%, 5%, and 10% for uterus, rectum, bladder, and sigmoid, respectively. Also, combined standard uncertainty was estimated as 3.5% (k = 1). CONCLUSIONS: A customized pelvis phantom was successfully built and assessed to confirm properties similar to body tissues. Additionally, no significant perturbation effect with different bead resolutions was presented by the external TPS, with 0.1 mm dose grid resolution.

Evaluation of ferrous benzoic methylthymol-blue gel as a dosimeter via magnetic resonance imaging.

PURPOSE: In previous studies, methylthymol-blue and benzoic acid have been introduced as a diffuser limiter and sensitivity enhancer in the gel dosimeter composition, respectively. This work focused on analyzing a formulation of the Fricke gel dosimeter consisting of methylthymol-blue and benzoic acid through magnetic resonance imaging. METHODS: The gel dosimeter samples were irradiated using 6, 10, and 15 MV photons with different levels of doses and read using a 1.5 T scanner in order to evaluate the dose-response sensitivity and to study the effect of benzoic acid concentration, diffusion coefficient and temperature and to determine the temporal stability of the gel dosimeter. RESULTS: Inspection of radiological properties revealed that this gel dosimeter can be considered as a tissue equivalent medium. Within the dose range 0 to 1000 cGy, the R1 sensitivity and R2 sensitivity of the gel dosimeter equaled 0.058 ± 0.003 and 0.092 ± 0.004 s-1Gy-1, respectively. The diffusion coefficient was less than 0.85 ± 0.02mm2h-1 for doses higher than 200 cGy. In addition, by changing the temperature from 15C to 25, the R1 sensitivity and R2 sensitivity decreased about 5 and 11%, respectively. Further, no significant energy and dose rate dependence were observed over photon energies of 6, 10, and 15 MV and over the range 65 to 525 cGy min-1. CONCLUSIONS: Based on our observation, the ferrous benzoic acid methylthymol-blue gel dosimeter can be suggested to measure the dose distribution. Further analysis is required to clarify its performance in clinical situations.

Evaluation of lung heterogeneity effects on dosimetric parameters in small photon fields using MAGIC polymer gel, Gafchromic film, and Monte Carlo simulation.

In this work, the performance of MAGIC polymer gel in measuring dosimetric parameters beyond lung heterogeneity in small fields was investigated. All data were obtained using MAGIC, EBT2, and MC in four small field sizes. The maximum local differences between MAGIC and MC were less than 5.1, 3.9, 3.1, and 2.6% for PDD values behind lung heterogeneity at 5, 10, 20, and 30 mm field sizes, respectively. The findings showed that MAGIC is a suitable tool for dosimetry behind low-density heterogeneity.

Success and Behavior During Atraumatic Restorative Treatment, the Hall Technique, and the Stainless Steel Crown Technique for Primary Molar Teeth.

Purposes: The purposes of this prospective trial were to: (1) compare the clinical and radiographic outcomes of three restorative methods -modified atraumatic restorative treatment (mART), the Hall technique (HT), and stainless steel crown (SSC)-in primary molars with multi-surface carious lesions; and (2) assess child behavior throughout these treatments. Methods: In this randomized controlled trial (RCT), 123 primary molars in four- to nine-year-old children were randomly divided into treatment groups (HT, mART, and SSC). Variables, including signs of failure, treatment time, child's discomfort, child's behavior, and canine overbite relationship in HT, were recorded immediately after the treatment and at six- and 12-month recalls. Results: Failures occurred most significantly for mART at all recalls (P=0.001). The treatment time was significantly higher in SSC. There was no significant difference in the child-assessment of discomfort (P=0.814). The child's behavior, as evaluated by the dentist, however, was significantly better for the SSC group. Alterations to the canine overbite relationship of HT decreased significantly during recalls (P<0.001). Conclusions: The high success and shorter treatment time of the Hall technique support its consideration as an alternative to the conventional technique for the treatment of carious primary teeth with multisurface lesions. The results for modified atraumatic restorative treatment were not as satisfying.

Mitigation of radiation-induced hematopoietic system injury by melatonin.

BACKGROUND: Increased risks of exposure to accidental radiation events are a concern in today's world. Radiation terror, nuclear explosion, as well as accidental exposure to radioactive sources in some industries pose a threat to the life of exposed persons. Studies have been conducted using some low-toxic agents to mitigate radiation toxicity and increase survival probability for exposed people. In the current study, we aimed to show the mitigation of radiation-induced mortality and bone marrow toxicity using postirradiation treatment with melatonin. METHOD: Mice whole bodies were exposed to 4 or 7 Gy radiation followed by treatment with melatonin after 24 hours. Survival of mice with or without melatonin, the levels of peripheral cells, transforming growth factor (TGF)-ß and 8-hydroxy-2' -deoxyguanosine (8-OHdG) in the bone marrow, as well as the expression of NADPH oxidase (NOX)2 and NOX4 in bone marrow cells were evaluated. RESULTS: Whole body irradiation led to mortality 30 days after irradiation. However, melatonin treatment reduced mortality. Irradiation also showed severe reduction of lymphocytes, platelets, and red blood cells. The expressions of NOX2 and NOX4, in addition to TGF-ß level, were increased after exposure to radiation. Melatonin ameliorated the increased levels of these factors and improved the number of blood cells. CONCLUSIONS: Melatonin showed ability to mitigate radiation-induced hematopoietic system toxicity and also increased survival rate. These results suggest that melatonin could be a potential mitigator for accidental radiation events.

Melatonin a Promising Candidate for DNA Double-Stranded Breaks Reduction in Patients Undergoing Abdomen-Pelvis Computed Tomography Examinations.

BACKGROUND AND OBJECTIVE: Cancer incidence is 24% higher in children and young adults exposed to Computed Tomography (CT) scans than those unexposed. Non-repairing of ionizing radiation-induced DNA Double-Strand Breaks (DSBs) can initiate carcinogenesis. In the present study, we aimed to investigate the radioprotective potential of melatonin against DSBs in peripheral blood lymphocytes of patients undergoing abdomen-pelvis CT examinations. METHODS: This double-blind, placebo-controlled clinical trial was conducted on thirty patients. These patients were divided into two groups; group one (control) patients who have undergone the CT examination received a single oral dose of placebo, while in group two, patients received a single oral dose of 100mg melatonin. In both the groups, blood samples were collected 5-10min before and 30 minutes after the CT examination. The lymphocytes from these samples were isolated and DSBs were analyzed using γH2AX immunofluorescence microscopy. RESULTS: Compared to the control group, the use of melatonin 1h before the CT examination caused a significant reduction in γH2AX-foci, indicating a reduction in DSBs. In addition, no side effect was observed in patients following 100mg melatonin administration. CONCLUSION: For the first time, this study has shown that melatonin has protective effects against radiationinduced genotoxicity in peripheral blood lymphocytes of patients undergoing abdomen-pelvis CT examinations. Therefore, melatonin can be considered as a promising candidate for reducing DSBs in patients undergoing abdomen-pelvis CT examinations.