[ efficacy of an endodontic instructional multimedia program for enhancing the knowledge and skills of dental students]

Full-scale demonstration of treatment phases on actual patients by an instructor is currently the conventional technique for practical instruction on endodontics. In this method, most students do not get the chance to closely observe the clinical procedure due to the small size of oral cavity. This study aimed at assessing the efficacy of an instructional multimedia program in endodontics for enhancing the knowledge and skills of dental students. In this randomized interventional trial, students taking the course of clinical endodontics were divided into two groups receiving conventional live demonstration alone or in combination with an instructional multimedia [DVD]. Baseline knowledge of students and their level of knowledge and skills after the intervention regarding practical endodontics were assessed by a pre-test and post-test, respectively. Data were compared between the two groups using Kruskal Wallis test. No significant differences were noted between the two groups in terms of knowledge or practical skills of students. However, the multimedia instruction significantly reduced the number of student inquiries to instructors for troubleshooting [P<0.001]. Due to the lack of a significant difference between the two instructional techniques, the multimedia instruction technique may be successfully used as a complement to current conventional techniques for practical instruction on endodontics

effectiveness of Mtwo and step back instrumentation techniques on the elimination of enterococcus faecalis from root canal

The aim of this study was to compare the effect of Mtwo rotary system and step back hand system in reduction of enterococcus faecalis bacteria from the root canals of human extracted teeth. In this study, 62 human extracted teeth were divided into two equal experimental groups with 23 teeth each and one control group two extra control groups with 5 teeth each as negative and positive were chosen for confirmation of the canal reinfection too. All of the samples were prepared by K Flie No 20 and Gates Glidden No 2 and 3 before sterilization. Then the teeth were autoclaved and reinfected with enterococcus faecalis. The experimental groups were instrumented either with Mtwo system or step back system. Bacteriological samples were taken after instrumentation to determine the amount of remaining bacteria. In the group 1, fourteen samples and in the group 2, twelve samples represented complete reduction of bacteria. There was not statistically significant difference between two techniques [p>0.05]. Both Mtwo and step back systems are the same on reduction of the bacteria from root canal system, up to the same apical size

[ effectiveness of Hero [taper 4% and 6%] instrumentation techniques on the elimination of Enterococcus faecalis from root canal]

Due to the deeper penetration of bacteria like Enterococcus faecalis into dentinal tubules in pulp diseases, different tapering in root canal therapies leads in different dentinal removal from root canal wall. Then, root canals with higher tapering will contain lower microbial contents. Furthermore, together with higher prevalence of root fractures in teeth with more tapering, the aim of this study is comparing the effect of different tapering of Hero Rotary files [6% versus 4%] in reduction of Enterococcus faecalis bacteria from the root canal of human extracted teeth. Seventy human extracted teeth were divided in two equal experimental [Hero 4%as group 1and Hero 6% as group 2] [n=27] and the control group [n=6].Two extra control group [positive n=5 and negative n=5] took for confirmation the canal reinfection, too. All of the samples prepared by K file No 20 and Gates Gilden No 2 and 3 before sterilization. Then the teeth were autoclaved and were infected with Enterococcus faecalis. The experimental groups were instrumented either with Hero 4% or with Hero 6% files up to #30. Bacteriological samples were taken after instrumentation to determine the level of remaining bacteria. In the group 1 two samples and in the group 2 six samples represented complete reduction of bacteria. There was not statistically significant different between the two groups. Aggressive preparation with an instrumentation technique removing substantial amounts of dentin [Hero 6%] did not reduce the intracanal bacteria more effectively than a more conservative instrumentation technique [Hero 4%] [P>0.05]

[Comparative study of antibacterial activity of propolis and Ca[OH]2 against lactobacillus, entrococus feacalis, peptostreptococus and candida albicans]

Elimination of root canal microorganisms is an important step in endodontic treatment. Each one of currently used medicaments has problems such as microbial resistance and tissue toxicity. Therefore, research is still needed to identify better alternatives. Propolis, as one of the honey bee products has been the focus of attention by many investigators in order to evaluate its biological properties. The aim of present study was to compare the activity of Calcium hydroxide and Propolis against lactobacillus, Enterococcus faecalis, Pepto-streptococcus and Candida albicans. This experimental study was conducted to evaluate antimicrobial activity of ethanol extract of Propolis and calcium hydroxide powder mixed with saline solution. Agar diffusion test and dilution methods were used to compare the results. There were separate plates to control diffusion of two substances in agar and antimicrobial activity of solvents. Figures about diameter of inhibition zone and minimal inhibitor concentration [MIC] and minimal bacterial concentration [MBC] were calculated using SPSS program. Paired T-test was used to compare the MIC experimental group differences. Propolis was more effective against Lactobacillus, Enterococcus Faecalis and Pepto-streptococcus with 8.6984mm compared with 7.0833mm mean diameter of inhibitory zone for Ca[OH]2. The difference was statistically significant [P<0.001] indicating that Ca[OH]2 was less effective against experimental microorganisms. The inhibitory zone of the two drugs demonstrated stronger effect of Propolis on contaminating microorganisms. On the other hand, the Minimal Inhibitory concentration of Propolis for all studied microorganisms was at least 4 times less than Calcium hydroxide. Propolis was more effective than calcium hydroxide against lactobacillus, Enterococcus faecalis and Pepto-streptococcus