Bacterial Leakage and Microgap along Implant-Abutment Connection in Three Different Implant Systems

A microgap between implant and abutment connection can act as a bacterial source and cause inflammation, even endanger Osseointegration and subsequently change clinical and histological parameters. The goal of this study was to evaluate the microgap and microbial leakage of implant-abutment connection in three different implant systems. In this experimental study, 28 implants in 3 groups (10 Zimmer with conical connection of 8 degrees, 10 Dentium with conical connection of 11 degrees, 8 Test implants with conical connection of 16 degrees) were used. Microleakage of Escherichia coli was assessed at intervals of 5, 24, 48 hours and 2 weeks. Microgap was measured at 4 random points by scanning electron microscope. Data were analysed by Spss version 22 and kruskal-Wallis, Mann-Whitney, Chisquare, Kaplan-Meier tests. (alpha=0.5) Mean microgap was 4.8 mu m (+/- 2.2) in Zimmer group, 3.1 mu m (+/- 1.4) in Implantium group and 16.9 mu m (+/- 8.7) in test group. After 2 weeks from start of the study, 20 percent of Zimmer and Dentium implants and 25 percent of test implant showed microleakage. Microleakage between Zimmer and Dentium implants was not significant; however, there was a significant difference between test implant and other groups. Microbial leakage was observed in all three implant systems. Although; there were differences in microgap between three groups, Microbial leakage was not statistically significant

Cell phone contamination among students and faculty members of the faculty of dentistry of Isfahan university of medical sciences

Background and Aims: The cell phone has played a significant role in the transmission of microbial contamination as a public tool. The present study was conducted to determine the degree of contamination of mobile phones of students and staff of the dental school of Isfahan University of Medical Sciences. Materials and Methods: In a cross-sectional study, 60 samples were taken from 60 cell phones belonging to students, staff and faculty members of the Isfahan Dental School, the samples were cultured in the laboratory for microbial contamination of the phone. The behavioral characteristics of the subjects were also determined using a cell phone special questionnaire. Data were analyzed by SPSS version 24 using descriptive statistics, one-way AVONA, T-test and Chi square. Results: Among the 60 cultured samples, 11 (18.3%) did not grow any bacteria. In 31 cases (51.7%), Staphylococcus epidermidis, 14 cases (23.3%) Staphylococcus aureus susceptible to methicillin and in 4 (6.7%) methicillin resistant staphylococcus aurous were grown. The mean of bacteria colonization was 18±12.2 and there was not any relation between the colonization and kind of bacteria (P=0.78) and studied groups (P=0.43). Also, there was a significant difference between the sanitary conditions and the type of bacteria grown in the culture medium (P=0.04). Conclusion: According to the results of the study, the cell phones belonging to the students, lecturers and faculty staff were contaminated by harmful bacteria such as staph aurous. These bacteria are the most important of nosocomial infections and may be led to a wide areas of infections from simple to serious types

Antimicrobial activity of a new nanobased endodontic irrigation solution: In vitro study

Aims: The purpose of this study was to introduce a nanosilver particle based endodontic irrigation solution and to evaluate its antimicrobial efficacy in comparison to 5.25% NaOCl. Materials and Methods: In an in vitro experiment the effect of the new irrigant against Enterococcus faecalis (ATCC: 29212) and Staphylococcus aureus (ATCC 25923), two most commonly isolated species of root canal space, was studied in different time intervals of 3, 5 and 15 minutes. Results: No growth of E. faecalis and S. aureus was observed in any of irrigant groups and any of different time intervals. Conclusion: These results indicate that the new irrigant is as effective as NaOCl in preventing the bacterial growth of common root canal bacteria

Teaching practical medical bacteriology accommodate with job analysis

Introduction: In routine procedure, education of practical medical bacteriology is not related with job analysis. The aim of this study was designing and performance of practical medical bacteriology education based on job analysis. Methods: This interventional study was performed in second semester in 1388-1389 in the practical course of bacteriology for 40 second-year medical students. The students randomly were divided to two groups (control, case) and education was performed according to routine and new process and evaluated with questionnaire and posttest. Data analysis was done by SPSS. Results: The mean of exam results in case group shows an increase of 8.5% comparing with control group According to questionnaire results all of the students were agree with necessity of change in educational program of practical bacteriology (63 and 91 in case and control group respectively). At the end of course, more than 70% of students in the case group achieved to the aims of the course (this was 9% in control group). Conclusion: The results of this study showed this method cause to more co-operations, interesting, and learning in practical courses. This new procedure is more related with job analysis comparing with routine methods. Students expect to learn issues that are more practical while common teaching methods address basic subjects regardless of the professional needs of students

Antimicrobial efficacy of antiplaque agents of common toothpastes against Porphyromonas gingivalis and Streptococcus oralis: An in vitro study

Background: This study was designed to evaluate the antimicrobial activity of common gum protection and antiplaque toothpastes against Porphyromonas gingivalis (P. gingivalis) and Streptococcus oralis (S. oralis) as important periodontal pathogens. Materials and Methods: This experimental study investigated the antimicrobial activity of 15 commonly used toothpastes from different companies on the two common types of periopathogens, S. oralis and P. gingivalis. The antimicrobial activity of toothpaste was evaluated at three concentrations of 100%, 50%, and 25% and analyzed by agar well diffusion plate method and zone of inhibition. The obtained data were compared and statistically analyzed by SPSS software using one-way ANOVA and the least significant difference post hoc tests (α = 0.05). Results: One-way ANOVA showed that the mean diameter of the two-bacterial zone of inhibition was significantly different at 100%, 50%, and 25% concentrations of toothpastes (P < 0.001). In general, the mean diameter of the zone of inhibition was greater at 100% concentration than the other two concentrations in all toothpastes. The highest zone of inhibition of the S. oralis was in the toothpastes containing tin. Further, the highest zone of inhibition of P. gingivalis was found in the triclosan-containing toothpastes. Conclusion: Toothpastes containing triclosan had the most antimicrobial activity against P. gingivalis. Moreover, toothpastes containing tin compounds had the most antimicrobial effect against S. oralis

Investigating the effect of Fusobacterium nucleatum on the aggressive behavior of cancer-associated fibroblasts in colorectal cancer

Abstract Fusobacterium nucleatum, (F. nucleatum) as a known factor in inducing oncogenic, invasive, and inflammatory responses, can lead to an increase in the incidence and progression of colorectal cancer (CRC). Cancer-associated fibroblasts (CAF) are also one of the key components of the tumor microenvironment (TME), which lead to resistance to treatment, metastasis, and disease recurrence with their markers, secretions, and functions. This study aimed to investigate the effect of F. nucleatum on the invasive phenotype and function of fibroblast cells isolated from normal and cancerous colorectal tissue. F. nucleatum bacteria were isolated from deep periodontal pockets and confirmed by various tests. CAF cells from tumor tissue and normal fibroblasts (NF) from a distance of 10 cm of tumor tissue were isolated from 5 patients by the explant method and were exposed to secretions and ghosts of F. nucleatum. The expression level of two markers, fibroblast activation protein (FAP), and α-smooth muscle actin (α-SMA), and the amount of production of two cytokines TGF-β and IL-6 from fibroblast cells were measured by flow cytometry and ELISA test, respectively before and after exposure to different bacterial components. The expression of the FAP marker was significantly higher in CAF cells compared to NF cells (P < 0.05). Also, the expression of IL-6 in CAF cells was higher than that of NF cells. In investigating the effect of bacterial components on the function of fibroblastic cells, after comparing the amount of IL-6 produced between the normal tissue of each patient and his tumoral tissue under 4 treated conditions, it was found that the amount of IL-6 production from the CAF cells of patients in the control group, treated with heat-killed ghosts and treated with paraformaldehyde-fixed ghosts had a significant increase compared to NF cells (P < 0.05). Due to the significant increase in FAP marker expression in fibroblast cells of tumor tissue compared to normal tissue, it seems that FAP can be used as a very good therapeutic marker, especially in patients with high levels of CAF cells. Various components of F. nucleatum could affect fibroblast cells differentially and at least part of the effect of this bacterium in the TME is mediated by CAF cells

PCR-based identification of methicillin–resistant Staphylococcus aureus strains and their antibiotic resistance profiles

Objective: To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods: A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates. Results: Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA-positive in the PCR assay. Conclusions: This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic

Comparison of the Prevalence of Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) among Staphylococcus aureus Isolates in a Burn Unit with Non-Burning Units

Background: Staphylococcus aureus (S. aureus) is one of the most important pathogens in burn infections colonized in the nose and increase the risk of infections. Methods: Overall, 85 S. aureus isolates were isolated from clinical and nasal hospitalized patients and health care workers (HCWs) in a burn unit and non-burn units in Isfahan from June 2016 and September 2016. Genes encoding penicillin-binding protein 2a (mecA) and adhesive surface proteins, including fibronectin-binding proteins (fnbA, fnbB), fibrinogen binding protein (fib), laminin-binding protein(eno), collagen binding protein (cna), elastin binding protein (ebps), intracellular adhesion operon (icaA and icaD) were detected using PCR method. Results: The rate of methicillin-resistant S. aureus (MRSA) among burn and non-burn isolates were 62% (18/29) and 25% (14/56), respectively. The most prevalent MSCRAMMs genes in burn units were eno (86%) and fib (66%). The most common gene pattern in burn center was icaA+fib+eno. The frequency of icaD, fib and ebpS was higher in clinical samples than nasal samples. No relation was found between the MSCRAMMs genes in the burn unit and non-burn units. Conclusion: The high prevalence of MRSA in burn center can be a new challenge for clinicians. The higher frequency of icaD, fib and ebpS in clinical isolates than nasal isolates may reflect the important role of these genes in colonization and pathogenesis of S. aureus

Comparison of antimicrobial effect of several decontaminating methods on contaminated Titanium discs

Background: Decontaminating the implant surface, exposed to bacterial biofilm, is a concern in the treatment of peri-implant inflammatory disease.The aim of this study was to compare the effect of several methods on reduction of the bacterial load, colonized on the surfaces of titanium discs. Materials and Methods: In this in vivo study, seven titanium discs with Sandblasted, Large-grit, acid-etched (SLA) surface were placed in the mouth of each of ten patients with chronic periodontitis by an intra-oral maxillary splint for 24 h. In each patient, the contaminated discs, except for the negative control ones, were randomly treated by one of the six antiseptic methods including sterile normal saline, plastic curette, air polisher, hydrogen peroxide, 980 nm diode laser, and Er-YAG laser. A spectrophotometer was used to measure Optical Density (OD) in case of aerobic microorganisms. Colony-Forming Units (CFUs) were used for anaerobic bacteria. Data were analyzed through Kruskal–Wallis and Mann–Whitney Tests at a significance level of α =0.05 by SPSS software. Results: Statistical analysis showed a significant decrease in OD of aerobic bacteria among the seven groups during a 0–24 h time interval (P < 0.001). Furthermore, these tests showed a significant difference in the CFU (P < 0.001) for anaerobic bacteria after 48 h. Conclusion: The results of this study showed that all of the adopted methods significantly reduced microbial colonies on the surfaces of titanium discs with SLA surface. Er: YAG laser and normal saline had the highest and the lowest effects, respectivel