AgNps-CN have shown potential in inhibiting HSC-4 cell lines. IC was low compared to few studies involving biosynthesized of silver nanoparticles. Apoptosis effects were shown towards HSC-4 cell lines by the increased in Bax/Bcl-2 protein ratio. Further study such as PCR or in vivo studies are required.

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Aim: This study was to determine the antibacterial activity of Melastoma malabathricum stem bark acetone extract (MMSBAE) against Streptococcus mutans. Methodology and results: Antibacterial activity of the extract was determined by minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), biofilm formation, adherence inhibition, time kill studies and effect on S. mutans membrane integrity. MIC and MBC values of MMSBAE were 1.25 and 5 mg/mL, respectively. Time kill studies showed that reduction of colony forming unit in treated cells is 3 log10 after 10 h of treatment (p ˂ 0.05). The extracts reduced 50% biofilm and adherence activity of S. mutans at 1.88 mg/mL. The effect on S. mutans membrane integrity after exposure to MMSBAE for 90 and 120 min was determined by measuring leakage of cell content at 2 different wavelengths of 260 nm and 280 nm. In leakage assay, the percentage of absorbance (260 nm) in treated cell material showed 57% at 90 min and 60% at 120 min which is higher than negative control (<20%) but less than positive control (100%). The percentage absorbance of treated cell material (280 nm) was 61% at 90 min and 63% at 120 min. Identification of compound in MMSBAE was done by gas chromatography mass spectrometry (GCMS). Ten compounds were identified in the MMSBAE with some of them important in antimicrobial activity such as ethyl ester, undecene, and gamma sitosterol. Conclusion, significance and impact of study: MMSBAE showed excellent bactericidal and antibacterial activities against S. mutans. The antibacterial mode of action of MMSBAE is suggested to be the disruption of the S. mutans membrane structure. The MMSBAE significantly inhibited biofilm and adherence activities of S. mutans in dose dependent manner (p ˂ 0.05). MMSBAE has potential in the development of antibacterial agent with anti-biofilm and anti-adherence activities.

Background. Acmella paniculata has been used as a traditional medicine to treat oral health diseases such as dental caries and periodontitis. Streptococcus mutans is a common bacterium that initiates dental caries at an early stage. Aim. The aim of this study was to determine the mode of action of A. paniculata (extracts) against S. mutans growth. Methods. Time-kill assay has been done to investigate the rate of kill and effectiveness of Acmella paniculata (AP) extracts against S. mutans growth. Phytochemical analysis was done to identify major compounds in AP extracts using gas chromatography mass spectrometry (GCMS). Scanning and transmission electron microscopy (SEM and TEM) have been done to observe the morphological changes of treated bacteria. Transcriptomic profile analysis has been done using Next Gene Sequencing. Results. AP flower n-hexane (APFH) and AP flower dichloromethane (APFD) extracts acted as bactericidal agents after killing >3 log10 cfu/mL of S. mutans after 24 hours. Oleic and hexadecenoic acids were found to be the major compounds in APFD and APFH extracts, respectively. Photomicrographs from SEM and TEM of treated S. mutans show that the bacterial cell wall has been lysed and the cytoplasm content was decreased. Pathway analysis revealed that the APFD extract significantly affected biosynthesis peptidoglycan, gene expression, RNA processing, and macromolecule metabolism processes in S. mutans. Conclusion. Data analysis revealed that multiple mechanisms of action were involved in antibacterial activity of A. paniculata extracts toward S. mutans.

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The understanding and capability to simulate reproducible in vitro plaque model are important where this artificial plaque can be utilized as a tool in assessing the efficacy of tooth cleaning products. Previous studies were done on synthetic surfaces such as glass beads under a very strict, controlled environment. Thus, the aim of this study was to establish a simplified system to enable the formation of single species biofilm on the extracted natural tooth as plaque model. Healthy extracted natural tooth was incubated in broth mixture of Streptococcus mutans, containing 5% sucrose and stimulated saliva in a simplified system. The incubation was set at room temperature for 24, 48, and 72 hours. After 24 hours, the sticky deposit was formed on the surface of the tooth. The area of biofilm, stained with disclosing agent, expended from 19.05 ± 1.41 mm 2 (24 hours) to 23.25 ± 0.35 mm 2 (48 hours). However, no significant expansion of the plaque area was observed on 72 hours (23.83 ± 0.52 mm 2 ). The biofilm was then observed under Infinite Focus Microscope (IFM) to measure the biofilm thickness. The preliminary attempt showed that plaque appeared as dark deposit with a certain thickness. Therefore, this simplified system is a reliable method for producing artificial plaque.

Coronavirus Disease 2019 (COVID-19) is an acute infectious disease that causes global outbreaks. The COVID-19 outbreak has forced various sectors to change their approach and daily practice to new alternatives. Dental education is no exception to the effects of this pandemic, which has severely disrupted teaching, learning and clinical activities. The impact of this pandemic on dental education can be classified into different aspects, including academic, practical, research and clinical services. Teaching and learning activities have been transformed into distance learning methods. However, dental educators are still struggling with psychomotor components, including practical and clinical sessions, which are the main course components that are severely affected. This sharing of experience focuses on the effects of the pandemic on the delivery of dental education and the actions taken by the Faculty of Dentistry, Universiti Sains Islam Malaysia (USIM) to ensure continuous learning. The challenges faced by the faculty are overcome with careful planning and discussion through the establishment of specific committees related to various issues, such as online learning and clinical COVID-19 committees. The committees identify any issues, plan the strategies and monitor the implementation of the plan. All actions during the pandemic are closely monitored by managing the faculty and university to ensure implementation of organised and smooth work, good record keeping, and compliance with instructions and guidelines by the authority.

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