Occupational Stress and Coping Behaviours Among Dentists in Kerman, Iran

Objectives: Recognising causes of stress can help prevent associated adverse effects. This study aimed to investigate causes of occupational stress and coping behaviours among general dentists in Iran. Methods: This cross-sectional study was carried out from April to December 2014. A modified version of the Occupational Stress Indicator questionnaire was used to assess causes of stress and coping behaviours among 142 general dentists in Kerman, Iran. Results: A total of 93 dentists participated in the study (response rate: 65.5%). Of these, 58.9% reported often being stressed. The mean general stress score was 63.33 ± 19.99. The most common causes of stress were maintaining high levels of concentration while working (65.6%), time pressures (64.5%), concern over their ability to deliver dental services in future (60.2%) and rising costs (59.1%). No significant relationships between stress and gender, age, workplace or working hours per week were noted (P >0.05). However, there was a significant correlation between general stress scores and years of job experience (P = 0.05) and number of patients treated daily (P = 0.03). The most common methods for coping with stress were resting (71.0%), sports (45.2%) and entertainment (43.0%). Most dentists felt that stress management courses could help to reduce stress (89.7%). Conclusion: General dentists in Kerman were subject to many sources of stress in their workplaces, with significant relationships between stress scores and years of work experience and number of patients treated daily. Dentists should be encouraged to participate in stress management courses to help alleviate stress

Hybrids of the bHLH and bZIP Protein Motifs Display Different DNA-Binding Activities In Vivo vs. In Vitro

Minimalist hybrids comprising the DNA-binding domain of bHLH/PAS (basic-helix-loop-helix/Per-Arnt-Sim) protein Arnt fused to the leucine zipper (LZ) dimerization domain from bZIP (basic region-leucine zipper) protein C/EBP were designed to bind the E-box DNA site, CACGTG, targeted by bHLHZ (basic-helix-loop-helix-zipper) proteins Myc and Max, as well as the Arnt homodimer. The bHLHZ-like structure of ArntbHLH-C/EBP comprises the Arnt bHLH domain fused to the C/EBP LZ: i.e. swap of the 330 aa PAS domain for the 29 aa LZ. In the yeast one-hybrid assay (Y1H), transcriptional activation from the E-box was strong by ArntbHLH-C/EBP, and undetectable for the truncated ArntbHLH (PAS removed), as detected via readout from the HIS3 and lacZ reporters. In contrast, fluorescence anisotropy titrations showed affinities for the E-box with ArntbHLH-C/EBP and ArntbHLH comparable to other transcription factors (Kd 148.9 nM and 40.2 nM, respectively), but only under select conditions that maintained folded protein. Although in vivo yeast results and in vitro spectroscopic studies for ArntbHLH-C/EBP targeting the E-box correlate well, the same does not hold for ArntbHLH. As circular dichroism confirms that ArntbHLH-C/EBP is a much more strongly α-helical structure than ArntbHLH, we conclude that the nonfunctional ArntbHLH in the Y1H must be due to misfolding, leading to the false negative that this protein is incapable of targeting the E-box. Many experiments, including protein design and selections from large libraries, depend on protein domains remaining well-behaved in the nonnative experimental environment, especially small motifs like the bHLH (60–70 aa). Interestingly, a short helical LZ can serve as a folding- and/or solubility-enhancing tag, an important device given the focus of current research on exploration of vast networks of biomolecular interactions

Cytotoxic effects of new MTA-based cement formulations on fibroblast-like MDPL-20 cells

Abstract The present study aimed at evaluating the cytotoxic effects of a novel cement called CER on periodontal fibroblast-like cells of mice (MDPL-20), in comparison with different formulations of Mineral Trioxide Aggregate (MTA), by means of the cell viability test (MTT) and cell morphology analysis. Thirty-two round-shaped samples were fabricated with the following cements: white MTA, white and gray CER and experimental white MTA. The samples were immersed in serum-free culture medium for 24 hours or 7 days (n = 16). The extracts (culture medium + components released from the cements) were applied for 24 hours to previously cultured cells (40.000 cells/cm2) in the wells of 24-well plates. Cells seeded in complete culture medium were used as a negative control. Cell viability was assessed using the MTT assay. Two samples of each cement were used for cell morphology analysis by Scanning Electron Microscopy (SEM). The extracts obtained at the 7-day period presented higher cytotoxicity compared with the 24-hour period (p 0.05). However, at the 7-day period, the experimental white MTA presented no significant difference in comparison with the other cements (p > 0.05). At the 7-day period, CER cement presented cytotoxic effects on fibroblast-like cells, similar to different MTA formulations. However, the immersion period in the culture medium influenced the cytotoxicity of the cements, which was greater for CER cement at 24 hours

Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis

Objective: Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature. Material and Methods: A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05. Results: Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115). Conclusions: According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes

Bibliometric Study of periodontal publications by Iranian authors between 1995-2015: A Medline approach

BACKGROUND AND AIM: One of the methods to measure scientific achievement in a particular field is bibliometric analysis of scientific publications. The main goals of this study were bibliometric analysis of Iranian periodontal literature, study design, and topics investigated in periodontal research published from 1995 to 2015 in PubMed. METHODS: PubMed search strategy was developed to identify all the international papers published in the field of periodontology (periodontics) by the Iranian scientists between 1995 and 2015. We performed the search protocol by typing "periodont*" in the title/abstract search box, and also the word "Iran" in the affiliation search box. We reviewed all the abstracts and removed the unrelated articles from the study. Retrieved data were analyzed using SPSS. RESULTS: Total of 178 papers from 83 peer-reviewed journals were found from the PubMed database and were reviewed. Seventy articles (37.4) were published in Iranian PubMed indexed journals, and 117 (62.6) papers were published in the journals of other countries. According to the publication type of the articles, 173 (92.5) of them were original research papers, 6 articles (3.2) were review papers, and 5 papers (2.7) were case reports. The results indicated that maximum number of articles was published in 2013. The most frequent article types were cross-sectional studies (29.9) followed by clinical trials (22.5) and case-control studies (18.7). CONCLUSION: In recent years, the periodontal research production has made significant progress in Iran. It seems that the Iranian periodontists should emphasize more on the design and quality of works in addition to the quantity of articles