Impact of air pollution on vitamin D deficiency and bone health in adolescents.

The association between air pollution and bone health was evaluated in adolescents in the city of Tehran. This study is essentially ecological. Vitamin D deficiency among adolescents has been reported at higher rates in polluted areas than in non-polluted areas. Additionally, residence in polluted areas is associated with lower levels of bone alkaline phosphatase. PURPOSE: The aim of this study was to evaluate the association between ambient air pollution and bone turnover in adolescents and to compare the prevalence of vitamin D deficiency between polluted and non-polluted areas of Tehran. METHODS: This cross-sectional population-based study was conducted on 325 middle- and high-school students (both girls and boys) in Tehran in the winter. During the study period, detailed daily data on air pollution were obtained from archived data collected by Tehran Air Quality Control Company (AQCC). Serum levels of calcium, phosphorus, parathyroid hormone (PTH), bone-specific alkaline phosphatase, 25(OH) vitamin D, osteocalcin, cross-linked C-telopeptide (CTX), total protein, albumin, and creatinine were obtained from the study group. RESULTS: Vitamin D deficiency was more prevalent in polluted areas than in non-polluted areas. After adjustment for age and sex, residence in the polluted area showed a statistically significant positive association with vitamin D deficiency and a statistically significant negative association with bone turnover. Interestingly, high calcium intake (>5000 mg/week) protects against the effects of air pollution on bone turnover. CONCLUSIONS: Air pollution is a chief factor determining the amount of solar UVB that reaches the earth's surface. Thus, atmospheric pollution may play a significant independent role in the development of vitamin D deficiency.

Direct costs of osteoporosis-related hip fractures: protocol for a cross-sectional analysis of a national database.

INTRODUCTION: It is estimated that Iran accounted for about 1% of hip fracture burden of the world in 2007, but these data are based on incomplete evidence. As the country's population is ageing, it is expected that a dramatic rise in hip fracture incidence will result. There is no single national study that accurately estimates the incidence of all hip fractures in the country or identifies the direct costs for affected patients. To help fill this gap, the current study has been designed to determine the incidence of hip fracture associated with osteoporosis in the Iranian population and to assess the direct costs involved. METHODS AND ANALYSIS: This is a cross-sectional analysis of 2 years of hospital admissions due to hip fracture in Iran from October 2014 to October 2016 using an electronic health record called SEPAS. SEPAS is a nationwide health information system established by Information Technology (IT) and the Statistics Department of the Ministry of Health. SEPAS has recorded more than 8.5 million inpatient hospitalizations since October 2014. Our study will identify reported hip fracture data in SEPAS among admitted adult hospital patients aged ≥50 in Iran. International Classification of Diseases ICD-9 and 10 will be used as diagnostic codes. Study factors are demographic data, types of fracture, types of treatment, duration of admission, early complications, in-hospital mortality and direct cost of fracture treatment. The accuracy of the SEPAS fracture data will be ascertained through a pilot study that compares the SEPAS data with the data directly extracted from medical records of the Shariati Hospital in Tehran during the study period. ETHICS AND DISSEMINATION: The study protocol was approved by the Ethics Committee of the National Institute for Medical Research Development of Iran. Dissemination plans include academic publications, conference presentations and social media.

In vitro and ex vivo antimicrobial efficacy of nano-MgO in the elimination of endodontic pathogens.

OBJECTIVES: The use of metal oxide nanoparticles has attracted lots of attention, mostly because of their promising antimicrobial activity along with their biocompatibility with mammalian cells. This study aims to investigate the in vitro and ex vivo antimicrobial efficiency of nano-magnesium oxide (MgO) aqueous solution against endodontic pathogens. MATERIALS AND METHODS: The cytotoxicity of different concentrations of nano-MgO was assessed using lactate dehydrogenase cytotoxicity assay (LDH assay). A comparison of the antimicrobial efficiency of several concentrations of nano-MgO solution, sodium hypochlorite (NaOCl), and chlorhexidine (CHX) gluconate against Staphylococcus aureus, Enterococcus faecalis, and Candida albicans was made using the direct contact method. An ex vivo model of decoronated and experimentally infected human teeth was employed to compare the efficiency of nano-MgO (5 mg/L) solution with NaOCl (5.25 %) in the elimination of E. faecalis. RESULTS: There was no statistically significant difference between nano-MgO solutions (10 and 5 mg/L), 5.25 % NaOCl, and 2 % CHX gluconate in terms of the required time to inhibit the growth of the tested pathogens (p > 0.05). The LDH assay showed no cytotoxicity of different concentrations of nano-MgO used in this study (p < 0.001). In the ex vivo model of infected human teeth, 6 h post-irrigation, there was no statistically significant difference between colony-forming units (CFU) per milliliter of nano-MgO (5 mg/L) and NaOCl (5.25 %)-treated teeth (5-6 log scale reduction). However, the nano-MgO group showed a significant decrease in colony-forming units per milliliter (7 log scale), 24 h post-irrigation (p < 0.05). At other tested time points-24, 48, 72, and 168 h-the levels of CFU per milliliter were significantly less in the nano-MgO group (2-3 log scale difference) compared to the NaOCl group, indicating long-term antibacterial activity of nano-MgO (p < 0.05). At 72 and 168 h post-irrigation, no detectable bacterial growth was observed in the nano-MgO group. The detection limit was 10 CFU/mL. CONCLUSIONS: Nano-MgO aqueous solutions represent promising antimicrobial activities, both in vitro and ex vivo with minimal toxicity. CLINICAL RELEVANCE: Compared to NaOCl (5.25 %), nano-MgO (5 mg/L) exhibits statistically significant long-term efficiency in the elimination of E. faecalis in the root canal system. After further investigations, nano-MgO could be considered as a new root canal irrigant.

A technique to ensure the reproducibility of a cast post and core.

The post-and-core pattern duplication technique is a simple, cost-effective, and accurate method of ensuring the reproducibility of a cast post and core. An acrylic resin pattern is fabricated for an endodontically treated tooth. The post portion of the pattern is duplicated with a polyvinyl siloxane impression material in the lower compartment of a container. The core portion is then duplicated with a polyether impression material in the upper compartment. After the original pattern has been retrieved, the duplicate resin pattern is fabricated in the provided space. This technique will improve efficiency if damage or loss of the pattern or the actual cast post and core occurs.