effect of two post-space preparation techniques on the seal of Resilon and gutta-percha obturation materials

The aim of this study was to compare the effect of post space preparation with Gates Glidden drills or hand files on the sealing ability of gutta-percha or Resilon obturation materials. One-hundred and four single-rooted human teeth were instrumented and divided into four experimental groups [n=21 each] and two groups of positive and negative control [n=10]. Forty-two roots of experimental groups were obturated with gutta-percha and Dorifill sealer; and 42 roots with Resilon/Epiphany self-etch using lateral compaction technique. Each gutta-percha or Resilon group was divided into two subgroups [n=21] and post-space prepared with either Gates Glidden drills or hand files and chloroform. After post space preparation, 5 mm of apical gutta-percha or Resilon was left intact. The whole system was sterilized with gamma-rays. Saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank test and Cox regression analysis. There were no significant differences between the sealing ability of gutta-percha and Resilon. Furthermore, no significant difference was found between two different methods of post space preparation [P>0.05]. Under the limitations of this ex vivo study, there were no significant differences between the sealing ability of Resilon and gutta-percha after post space preparation using Gates Glidden drills or hand files with the aid of chloroform

Coronal microleakage in root canals obturated with lateral compaction, warm vertical compaction and GuttaFlow system

Root canal obturation seals the root canal system to prevent re-entry and/or growth of microorganisms. The provision of an appropriate restoration to coronally seal the access cavity affects the success of endodontic treatment. The purpose of this study was to evaluate the coronal microbial leakage in root canals that were either filled by lateral compaction, GuttaFlow or warm vertical compaction. In this ex vivo study, 80 single-rooted human extracted teeth were randomly divided into three experimental groups [n=20] and two positive and negative control groups [n=10]. The teeth in experimental groups were obturated with cold lateral compaction, GuttaFlow system or warm vertical compaction techniques. After sterilization of the whole system with gamma-ray, saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank and Kaplan-Meier survival analysis tests. There were no significant differences in impeding saliva leakage between the three experimental groups [P>0.05]. Under the conditions of this ex vivo study, it can be concluded that the sealing ability of cold lateral compaction, warm vertical compaction and GuttaFlow system was comparable

In vitro comparison of the effectiveness of Chiorhexidine and two calcium hydroxide formulations on Enterococcus faecalis

The aim of this in vitro study was to compare the effectiveness of three intracanal medicaments in disinfecting the root canal and dentin of experimentally infected human teeth with Enterococcus faecalis [EF]. One hundred extracted human single-rooted teeth were used. After root canal preparation, teeth were mounted in epoxy resin. Following sterilization, the teeth were infected for 28 days with EF. Then root canals were filled with one of three different disinfectants: viscous 2% Chlorhexidine [CHX], calcium hydroxide paste [CH] or a mixture of CH and CHX [n=30 in each group]. Antimicrobial assessments were performed at 1, 3 and 7 days [n=10 in each time period]. Microbial samples were obtained from root canals before and after the experiment. Also dentin samples were examined. The data was analyzed using Two- Way ANOVA test. The findings showed that there was no difference between experimental groups at different time periods. The mixture of CH/CHX in 7 days was able to eliminate EF completely from root canal system. The most elimination of EF was from dentinal tubules. According to the results of this in vitro study, viscous 2% CHX, mixture of CH with distilled water and 2% CHX are all effective disinfectants

comparative study of antimicrobial activity of ProRoot MTA, Root MTA, and Portland cement on Actinobacillus actinomycetemcomitans

The purpose of our study was to evaluate the antibacterial effect of ProRoot MTA [PRMTA], Root MTA [RMTA] and Portland cement [PC] at their clinical concentration [70 mg/25 microL] against Actinobacillus actinomycetemcomitans [Aa] one of the prominent periodontal [pocket] microorganisms. Agar diffusion test on Blood Agar with Hemin and Vitamin K [BAHV] was employed in this study. The microorganisms were seeded on the BAHV by spreaders. Small holes, 6 mm in diameter, were made in the BAHV by removing agar. PRMTA, RMTA and PC were placed into the wells immediately after manipulation. The plates were incubated in anaerobic atmosphere at 37°C for 72 h and the zones of inhibition were measured. In the agar diffusion test PRMTA, RMTA and PC against Aa showed zones of inhibition. Analyzing the antimicrobial activity of PRMTA, RMTA and PC according to paired one-way ANOVA and Post Hoc Test [Turkey's test] analysis showed a statistically significant difference [P<0.05] between PRMTA, RMTA and PC. RMTA showed the largest zone of inhibition [29 mm] against Aa. There was no difference in the zones of inhibition between the 48 and 72 h time periods. In this in vitro study PRMTA and RMTA presented similar antimicrobial activity against Aa

Emergence of high-level vancomycin-resistant Staphylococcus aureus in the Imam Khomeini hospital in Tehran

The objective of the study was to investigate the prevalence of vancomycin-resistant Staphylococcus aureus [VRSA]. Three hundred and fifty-six S. aureus isolates from the Imam Khomeini hospital in Tehran, Iran, were evaluated for methicillin and decreased vancomycin susceptibility by the microbroth dilution method. The mecA, vanAand vanB genes were targeted by polymerase chain reaction. Of the 356 isolates, 149 [41.85%] S. aureus strains were resistant to methicillin. Two strains of methicillin-resistant S. aureus were VRSA strains. One isolate, Teaching Hospital-1 [TEH-1], had a vancomycin minimum inhibitory concentration [MIC] of 64 micro g/ml and was susceptible to teicoplanin while the other isolate [TEH-2] had a vancomycin and teicoplanin MIC of 512 and > 256 mg/ml, respectively, and was positive for the vanA gene. This report shows that the emergence of VRSA in Iran warrants active microbiological surveillance and careful monitoring of vancomycin therapy