atieh hashemian

Dental clinics are one of the major producers of mercury-containing waste due to the use of dental amalgam.  The atmospheric transport and persistence of mercury and its compounds in the environment, coupled with their high potential for bioaccumulation and detrimental effects on human health and ecosystems, underscore the necessity for effective management of mercury waste. Due to the lack of comprehensive and integrated guidelines for the effective management of dental amalgam waste in Iran, the objective of this study was to adapt a guideline for the management of amalgam waste in dental settings within the country.

The method used was based on the adaptation principles presented by the Ministry of Health and Medical Education, and included searching and reviewing guidelines related to the management of amalgam waste in developed countries, extracting recommendations, revising the recommendations considering the local infra-structures and conditions, and receiving expert opinions and reaching consensus according to the RAND/UCLA Appropriateness Method.

The final guideline includes 34 recommendations in 5 areas: manage-ment of the amalgam scraps, considerations for dental equipment, management of the extracted teeth containing amalgam restorations, management of the amalgam capsules, and considerations for placement and replacement of the amalgam restorations.

The use of this guideline in medical universities, public and private dental clinics, along with the supervisory role of the Ministry of Health and Medical Education, can be a way to minimize the environmental hazards of mercury.

The present study aimed to investigate the antibacterial properties of a conventional epoxy-based dental sealer modified with synthesized bioactive glass (BG), hydroxyapatite (HA), and fluorine-substituted hydroxyapatite (FHA) nano-fillers.

The synthesized nano-fillers were incorporated into the conventional epoxy-based dental seaer at the concentration of 10%. The antimicrobial properties of the unmodified sealers (controls) and modified seaers with BG, HA, and FHA nanoparticles (NPs) were evaluated based on biofilm formation and using the direct contact test (DCT) of Enterococcus faecalis and Streptococcus mitis. Data analysis was performed using one-way analysis of variance (ANOVA) and Tukey’s post-hoc test at the significance level of 5%.

A significant reduction was observed in the biofilm formation and DCT of the microbial strains in the three modified groups compared to the unmodified conventional epoxy sealer (P<0.05). The addition of FHA NPs resulted in the most significant antibacterial effects against E. faecalis and S. mitis, as well as a statistically significant reduction compared to the unmodified and BG-modified groups (P≤0.001).

According to the results of this preliminary study, nano-structured FHA, HA, and BG fillers incorporated into epoxy-based dental sealers could be potentially effective biomaterials for antibacterial approaches to root canal treatments.

Decrease in Heme Oxygenase-1 gene expression is associated with fewer amounts of reoccurrence and better final response to treatment in some cancers. The aim of this study was to analyze the effect of Zinc Protoporphyrin (Znpp), as Heme Oxygenase-1 (HO-1) inhibitor, and radiotherapy on melanoma cells in mice.

In this experimental study, 24 mice were randomly divided to 4 groups. On the first day of the study, melanoma cells were injected and the mice were treated for 16 days. First and second groups received 2000 mg/kg of Znpp every other day. Third and forth groups were injected diluted liquid of Znpp. The first and third groups received 12 gray of radiotherapy on 8th day. The mice were examined each day for any palpable tumors and size was measured. The tumors were extracted on the 16th day. The effect of HO-1 on growth of cancer cells was studied using mitotic index and the size of tumors were measured on 8th and 16th days.

Size of tumor and mitotic index in mice treated with Znpp and radiotherapy was significantly smaller than in control groups (P < 0.05). Size of tumor in mice treated by radiotherapy and Znpp was less than group only treated with radiotherapy (P < 0.05).

The HO-1 inhibitor with radiotherapy may have therapeutic effects and it may be more effective in reducing the tumor’s growth than using radiotherapy alone.