فاطمه اسمی

The traditional methods of teaching that are currently running do not alone meet the rapid growth of information and knowledge and the changing needs of societies. Knowing different methods of teaching and use of learning aids, will help teachers and students to heighten the steps toward making a difference in education. The aim of this study was to determine the effectiveness of an educational multimedia in teaching process. This study was performed on 30 dental students of the 6th semester of Babol dental school on the academic year of 2012-13. Students were divided into two equal groups and matched. Two groups were taught based on the traditional training method and the multimedia presentation. Their awareness was analyzed with the paired-T-test and the Independent-T-test according to the pre- test and the post-test scores. The mean scores of before and after the lecture in the lecture groups, were respectively (5/06 ± 1/9) and (9/93 ± 1/7), and the second group mean scores before and after viewing the educational multimedia, were (4/13 ± 1/4) and (10/33 ± 1/2), respectively. Paired-T-test showed that the mean of before and after scores for each experimental group significantly increased (P<0/05. To compare the two groups, the Independent-T-test was used. The results of this test showed that the difference between the two groups before and after the study was not significant in any of the groups (p>0/05). We can conclude that an educational multimedia of the tooth restoration can be used successfully to increase the knowledge of dental students.

Recently، one of the important titles in dentistry is usage of nanoparticles in improvement of antibacterial properties of resin composites. There are many interesting findings about the decrease in bacterial growth adding nanoparticles to resin composite. Since there are many interests to Nano Zinc Oxide as an antibacterial agent، in this study، we evaluated antibacterial effect of zinc oxide against streptococcus mutans. In this in-vitro study، 30 samples in 2 microbiological test majors were evaluated (disc diffusion test and direct contact test). There were 5 groups of Resin Modified Glass Ionomer (RMGI) (Fuji II LC) containing different weight percent of Zinc Oxide (ZnO) nanoparticles (0%، 1%، 2%، 3% and 5%، respectively) and there were 3 samples in each group. These particles were mixed with RMGI powder by mortar and pestle in 20 minute after nanoparticles weighting by digital balance. For disc diffusion test، 15 discs of experimental GI were cured in 2mm × 8mm plastic mold and their anti-streptococcus mutants effects were evaluated in agar culture. Antibacterial effects of 15 micro-tubes containing different groups of RMGI were evaluated in direct contact test. In disc diffusion test there was significant increasing in non-growth halo of bacteria around the discs by increasing in nanoparticles percentage. In direct contact test there was no significant difference between 1، 2، and 3 weight percent groups but there was a significant difference between specimens containing 5 weight percent in comparison with control group. The results of this study showed a considerable decrease in bacterial growth with Nano ZnO weight percent increase.

Periodontitis and dental caries may be synergistically associated, negatively associated, or completely independent. The aim of this study was to evaluate the correlation between these two diseases and investigate the prevalence of dental caries in periodontitis. This cross-sectional study has been performed in 180 samplesin two groups: periodontal and control group; during 2012-2013 in Babol Dental School. All 180 patients were divided into two groups, including 90 cases with chronic periodontitis as the periodontal group (PG) and 90 cases with healthy gums as the control group (probing depth between 2-3mm) (HG). Clinical measurments in cluding Gingival Index (GI), Bleeding Index (BI), Clinical Attachment Loss (CAL), Periodontal Pocket Depth (PPD) were used to assess the severity of periodontal disease. The clinical features of control group were healthy gums, probing less than 3mm in depth, and CAL<1mm. The examination to measure AL was conducted using a Williams’s periodontal probe. In chronic periodontitis group, the patients had GI≥1 and CAL≥1. The assessment of caries of patients was conducted using bitewing radiography for proximal caries detection, dent on the use of explorer and direct observation. A p-value≤0.05 is considered as significant. The results of this study showed that the mean number of decayed and filled teeth (DFT) in periodontal group was 4.32±0.17, and in healthy group was 2.16±0.17. DFT in males with periodontitis was 4.85±0.17 and in females was 4.3±0.17,while the healthy males was 2.54±0.17, and females was 2.25±0.17; therefore, the mean DFT in the periodontal group was more than the healthy group (p≤0.05). Based on our findings, in patients with periodontitis, more dental carries were more significant than the healthy group.

Since the preparation of antibacterial materials in dentistry is very noticeable, therefore, we tried to evaluate this effect on Streptococcus mutans by addition of silica nanoparticles to LCGI (light curing glass ionomer). In this in vitro study, we had five LCGI experimental groups that contained 0, 0.2, 0.5, 1, and 2% (w/w) of silica nanoparticles. For disc diffusion test, 15 samples were prepared and their anti-Streptococcus mutans effects in agar culture were evaluated. Antibacterial effects of 15 micro-tubes containing different groups of LCGI were evaluated in direct contact test. There were significant differences between specimens containing nanoparticles and control group in both disc diffusion and direct contact test. In disc diffusion test, bacterial growth inhibition hallo showed that LCGI penetrates into peripheral environment and disrupted bacterial growth. In direct contact test, samples showed significant bacterial growth inhibition. By increasing nanoparticles weight percent, there was a significant decrease in bacterial growth.

The use of nanoparticles in improvement antibacterial property of dental resins is one of the most important issues in recent studies. Studies which added these particles to resin materials have reported desirable results in decreasing bacteria’s growth. Titanium dioxide nanoparticles have been proposed for reinforcing fillers in dental resin composites and epoxy. The aim of this study was to evaluate the effect of adding titanium dioxide nanoparticles into a light cure glass ionomer on antibacterial properties of this resin against streptococcus mutans. In this in-vitro study، samples were divided into 5 light cure glass ionomergroups which contain respectively of 0 (as control group)، o. 5، 1، 3، 5 weight percentage of nano-titanium dioxide. 15 discs (3 from each experimental group) were cured in plastic frames with 2mm thickness and 8mm diameter، for disc diffusion test. Then antibacterial properties against streptococcus mutans were studied in chocolate agar culture. For Direct Contact Test، 15 micro-tubes containing resin groups (3 discs from each experimental group) were prepared and their antibacterial effect were evaluated after 3، 6 and 24 hours. The data was analyzed by Kruskal-Wallis Test and Mann-Whitney Test. In Disc Diffusion Test the amount of antibacterial effect around discs، containing 0. 5 nanoparticles was similar to halo around the other discs containing nanoparticles، and it was little more than control group. In Direct Contact Test، glass ionomers containing nanoparticles، number of bacteria was diminished on surface of resin groups that contain more percentages of nanoparticles at 3، 6 24 hours،. Four experimental groups did not reveal any significant difference، but it was diminished in compare to control group. However the growth of bacteria in both tests in comparison with control group was decreased، antibacterial property of samples that contain nanoparticles doesn’t show any significant difference. This property was more significant in direct contact with bacteria.