[ 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

Cytotoxicity comparison of nanosilver coated gutta- percha with Guttaflow and normal gutta-percha on L929 fibroblast with MTT assay

Gutta-percha is shown to be the most widely used root canal filing material due to its well-known low toxicity potential. A new kind of gutta-percha with nanosilver coating has synthesized by Iranian researchers and claimed to have antibacterial an antifungal properties. The aim of this study was to compare the cyotoxicity of nanosilver coated gutta-percha, GuttaFlow [GF], with normal gutta-percha [GP] on mouse fibroblast cell line L929. In this in vitro study, cytotoxicity was evaluated by fibroblast cell culture and its direct contact with the test materials. 30 specimens inserted in test tubes and cell survival fraction was estimated by MTT test after Ihour, 24 hour, and 1 week. Two way ANOVA, one way ANOVA and Tukey HSD were used for statistical analysis. After 1 hour, cytotoxicity among three 3 test materials was significantly different. Nanosilver coated gutta-percha had the highest cytotoxicity and GuttaFlow the lowest one [P<0.01]. After 24 hour, no significant differences were observed [P=0.37]. After 1 week, GuttaFlow showed significantly higher cytotoxicity than normal gutta-percha and nanosilver gutta-percha [P<0.001]. However, this difference was not significant between nanosilver and normal gutta-percha [P>0.05]. In nanosilver gutta-percha group, the most cytotoxicity was observed after 1 hour while it was decreased with time and became equal to normal gutta-percha after 24 hours and after 1 week, it reached the lowest level among 3 test materials

[Comparison of infradental nerve response to inflamed pulp after local application of Lidocaine and Lidocaine plus Morphine in cats]

Failure to obtain adequate anesthesia in teeth with inflamed pulps has been known as a clinical symptom for dentists. The aim of this study was to determine the infra-alveolar nerve response to supplementary injected morphine to Lidocaine in anesthetizing teeth with inflamed pulps. Thirty mandibular canine in 15 cats were exposed in order to become inflamed. The inferior alveolar nerve was exposed and the recording electrodes were placed upon it while the stimulating electrodes were placed on the teeth. By stimulating the teeth using the stimulator in different voltages, all the received nervous responses were recorded by means of an oscilloscope unit. If the fibers were not blocked a Lidocaine injection. supplementary injection with morphine was used and responses were recorded again. The data were analyzed by test. In teeth with inflamed pulps both morphine and/or Lidocaine had significant local anesthetic effects. Lidocaine and morphine acted quite similar and blocked the second group [c] fibers more rapidly and strongly than the first group [A delta] fibers. Supplementary injection of morphine in those cases in which Lidocainc failed to block the first group fibers raised the stimulation threshold and decreased the wave peak and the speed of the first group fibers [p > 0.05]. Pulpal nerves received morphinergic receptors during inflammation and resisted to the Lidocaine and became anesthetized after supplementary injection of morphine. Using morphine as an adjunct to Lidoeaine may complete the anesthetic effect on neurons in inflamed pulps