The effect of silver nanoparticles on composite shear bond strength to dentin with different adhesion protocols

In Dentistry, restorative materials and oral bacteria are believed to be responsible for restoration failure. To make long-lasting restorations, antibacterial agents should be made. Inorganic nanoparticles and their nano composites are applied as good antibacterial agents. Objective The purpose of this study was to investigate the effect of silver nanoparticles on composite shear bond strength using one etch and rinse and one self-etch adhesive systems. Material and Methods Silver nanoparticles were prepared. Transmission electron microscope and X-ray diffraction were used to characterize the structure of the particles. Nanoparticles were applied on exposed dentin and then different adhesives and composites were applied. All samples were tested by universal testing machine and shear bond strength was assesed. Results Particles with average diameter of about 20 nm and spherical shape were found. Moreover, it was shown that pretreatment by silver nanoparticles enhanced shear bond strength in both etch and rinse, and in self-etch adhesive systems (p≤0.05). Conclusions Considering the positive antibacterial effects of silver nanoparticles, using them is recommended in restorative dentistry. It seems that silver nanoparticles could have positive effects on bond strength of both etch-and-rinse and self-etch adhesive systems. The best results of silver nanoparticles have been achieved with Adper Single Bond and before acid etching

The effect of silver nanoparticles on composite shear bond strength to dentin with different adhesion protocols

Abstract In Dentistry, restorative materials and oral bacteria are believed to be responsible for restoration failure. To make long-lasting restorations, antibacterial agents should be made. Inorganic nanoparticles and their nano composites are applied as good antibacterial agents. Objective The purpose of this study was to investigate the effect of silver nanoparticles on composite shear bond strength using one etch and rinse and one self-etch adhesive systems. Material and Methods Silver nanoparticles were prepared. Transmission electron microscope and X-ray diffraction were used to characterize the structure of the particles. Nanoparticles were applied on exposed dentin and then different adhesives and composites were applied. All samples were tested by universal testing machine and shear bond strength was assesed. Results Particles with average diameter of about 20 nm and spherical shape were found. Moreover, it was shown that pretreatment by silver nanoparticles enhanced shear bond strength in both etch and rinse, and in self-etch adhesive systems (p≤0.05). Conclusions Considering the positive antibacterial effects of silver nanoparticles, using them is recommended in restorative dentistry. It seems that silver nanoparticles could have positive effects on bond strength of both etch-and-rinse and self-etch adhesive systems. The best results of silver nanoparticles have been achieved with Adper Single Bond and before acid etching

Effects of Stress Management Training on Cognitive Avoidance and Emotion Regulation Strategies in Female Students with Social Anxiety Disorder: A Mindfulness and Emotional Schema Therapy Approach

Background: Students with a social anxiety disorder (SAD) face a variety of problems such as early dropout, academic failure, and avoidance of social situations. The present study aimed to investigate the effects of mindfulness-based stress reduction training on cognitive avoidance and emotion regulation strategies in female students with SAD through an emotional schema therapy (EST) approach.Methods: In this semi-experimental study, a Pretest-Posttest Control Group design was used. The study population included female high school students with SAD in Ahvaz, Iran, in 2023. Out of 120 students with SAD who met the inclusion criteria, 75 were randomly selected as the study participants and were then assigned to three groups of 25 (two experimental groups and one control group). Training sessions for mindfulness-based stress management and EST were conducted in eight 90-minute sessions twice a week. For data collection, the Cognitive Avoidance Questionnaire and Emotion Regulation Questionnaire were used. Data analysis was done using the ANCOVA test and SPSS version 23. P-value less than 0.05 was considered significant.Results: In the posttest, mean±SD for cognitive avoidance, reappraisal, and suppression in the mindfulness-based stress reduction training group was 50.71±6.78, 32.87±2.65, and 14.08±5.68, respectively; suggesting a significant difference as compared with the control group (82.91±2.18, 12.53±6.75, and 20.81±2.74) (P<0.001). In addition, mean±SD for cognitive avoidance, reappraisal, and suppression in the EST group and the post-test phase was 61.52±5.71, 38.91±1.15, and 10.36±7.32, respectively; suggesting a significant difference as compared with the control group. The mindfulness-based stress management training was more effective than EST in reducing cognitive avoidance (P<0.001). By contrast, EST was more effective than mindfulness-based training in improving emotion regulation strategies (P<0.001).Conclusion: The study results suggested that mindfulness-based stress management training and EST can effectively reduce cognitive avoidance and improve emotion regulation strategies in students with SAD