Objective:Green tea extract (GTE) was shown to be effective in preserving periodontal ligament fibroblasts (PDLFs) of avulsed teeth. This study aimed at determining the potential of GTE in preserving the viability of PDLFs comparing with different storage media.Materials and Methods:Periodontal ligament cells were obtained from freshly extracted healthy impacted third molars and cultured in Dulbecco's Modified Eagle Medium (DMEM). Cell viability was determined by storing the cells in seven media; DMEM, tap water, Hank's balanced salt solution (HBSS), whole milk, hypotonic sucrose solution, GTE, and GTE + sucrose for 1, 2, 4, and 24 h at 37°C using tetrazolium salt-based colorimetric (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay. Statistical analysis was performed by one-way analysis of variance and post hoc tests.Results:GTE showed significantly higher protective effect than HBSS at 2, 4, and 24 h (P = 0.009, P = 0.02, P = 0.016), DMED at 2 h (P = 0.003), and milk at 4 h (P = 0.039).Conclusion:Although with undesirable osmolality and pH, GTE had a good ability in preserving the PDLFs comparing with other studied media.

Introduction: Identifying and employing students' learning styles could play an important role in selecting appropriate teaching methods in order to improve education. The aim of this study was to determine the relationship between the students' final exam scores and the learning style preferences of dental students at Babol University of Medical Sciences. Methods: This cross-sectional study was conducted on 88 dental students studying in their fourth, fifth, and sixth years using the visual-aural-reading/writing-kinesthetic (VARK) learning styles' questionnaire. The data were analyzed with IBM SPSS, version 21, using the chi-squared test and the t-test. Results: Of the 88 participants who responded to the questionnaire, 87 preferred multimodal learning styles. There was no significant difference between the mean of the final exam scores in students who did and did not prefer the aural learning style (p = 0.86), the reading/writing learning style (p = 0.20), and the kinesthetic learning style (p = 0.32). In addition, there was no significant difference between the scores on the final clinical course among the students who had different preferences for learning style. However, there was a significant difference between the mean of the final exam scores in students with and without visual learning style preference (p = 0.03), with the former having higher mean scores. There was no significant relationship between preferred learning styles and gender (p > 0.05). Conclusion:The majority of dental students preferred multimodal learning styles, and there was a significant difference between the mean of the final exam scores for students with and without a preference for the visual learning style. In addition, there were no differences in the preferred learning styles between male and female students.

Objective:This study sought to assess the inhibitory effect of chitosan-containing sealants against Streptococcus mutans.Materials and Methods:The antibacterial activity of the resin sealant was evaluated by direct contact test following the addition of 0, 1, 2, 3, 4, and 5 wt% chitosan. At 3, 6, 9, 24 and 48 h, 1 and 3 months, 10 μl of the microbial suspension in contact with resin sealant was cultured to count the number of colonies. Data were analyzed by one-way one-way analysis of variance (ANOVA), repeated measures ANOVA, and Scheffe test.Results:The minimum inhibitory concentration of chitosan against S. mutans was 2 wt%. At 3 h, bacterial count in the presence of 2–5 wt% chitosan was significantly lower than that at 0 and 1 wt% (P < 0.05). However, this difference in bacterial count between 2 and 3 wt% chitosan and between 4 and 5 wt% chitosan was not significant. At 6 h, the difference in bacterial count between 3 and 4 wt% chitosan was not significant, whereas the remaining groups were significantly different in terms of bacterial count at this time (P < 0.05). At the remaining time points, significant differences were found between 2 wt% chitosan and higher concentrations (P < 0.05).Conclusion:Sealants containing 2–5 wt% chitosan show an antimicrobial property that is intensified by increasing the concentration of chitosan.

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Context:Delayed replantation of avulsed teeth may be successful if the majority of periodontal ligament cells (PDL) survive. A proper transport medium is required when immediate replantation is not possible. Green tea extract (GTE) may be effective in preserving the cells because of its special properties.Aims:This study was done to evaluate the potential of GTE in periodontal ligament cells preservation.Materials and Methods:Fifty-four extracted human teeth with closed apices were randomly divided into three groups each with 18 teeth as follow: GTE, water (negative control), and Hank's balanced salt solution (HBSS) (positive control). The specimens were immersed in the media for 1, 3, and 15 hours at 4°C (n = 6) and treated with collagenase 1A for 45 minutes. Cell viability was determined using the trypan blue exclusion technique.Statistical Analysis:Data were analyzed by one-way analysis of variance (ANOVA), post hoc Tukey and paired t-test at significance level of P < 0.05.Results:Means (standard deviation, SD) of viable cells in HBSS, water, and GTE were estimated 348.33 ± 88.49, 101 ± 14.18, and 310.56 ± 56.97 at 1 hours; 273.4 ± 44.80, 64.16 ± 16.44, and 310.2 ± 11.21 at 3 hours; and 373.72 ± 67.81, 14.41 ± 2.88 and 315.24 ± 34.48 at 15 hours; respectively. No significant differences were found between HBSS and GTE at all the time intervals. Both these solutions could preserve the cells more than water significantly.Conclusion:GTE and HBSS were equally effective in preserving the cells and were significantly superior to water.