ABSTRACT
INTRODUCTION: The purpose of this in vitro study was to evaluate the dimensional accuracy, trueness, and precision of vinyl siloxane ether (VSXE) and polyvinylsiloxane (PVS) impression materials using different impression techniques. MATERIAL AND METHODS: A three-dimensional (3D) printed mandibular model with implants and metal rods served as the reference model. Impressions were taken in custom trays, resulting in four groups: PVS-closed-tray, VSXE-closed-tray, PVS-open-tray, and VSXE-open-tray. The reference model and impressions were scanned and analyzed using 3D analysis software to assess the trueness and precision within each group. RESULTS: There was significant difference in trueness between the groups, with PVS closed tray showing a higher deviation than VSXE-closed-tray and PVS-open-tray. VSXE-open-tray had the lowest deviation, which was statistically significant. In terms of precision, PVS-closed-tray showed the highest deviation, while no significant differences were found among the other groups. CONCLUSIONS: VSXE impression material with an open tray technique consistently demonstrated the highest levels of accuracy and precision. Conversely, PVS impression material with a closed tray technique yielded less favorable results. CLINICAL RELEVANCE: Better understanding of trueness and precision of new impression materials with new impression techniques will increase their clinical effectiveness.
Subject(s)
Dental Impression Materials , Dental Impression Technique , Denture, Overlay , Mandible , Polyvinyls , Siloxanes , Dental Impression Materials/chemistry , Siloxanes/chemistry , Humans , Dental Prosthesis, Implant-Supported , Printing, Three-Dimensional , In Vitro Techniques , Models, DentalABSTRACT
BACKGROUND: The present study was conducted to investigate the role of vitamin C versus platelet-rich plasma (PRP) against sodium fluoride (NaF)-induced cardiotoxicity and cell death in rats' myocardium. Previous studies suggest that NaF decreased cellular viability and intracellular antioxidant power. MATERIALS AND METHODS AND RESULTS: The present study revealed that NaF administration caused histological alterations in the cardiac muscle and increased the accumulation of intracellular reactive oxygen species, the expression of inducible nitric oxide synthases and proliferating cell nuclear antigen as well as collagen deposition in cardiac tissue. As supported by colorimetric analysis, an elevation in malondialdehyde level and a decrease in both superoxide dismutase (SOD) and thioredoxin-1 oxidoreductase (TrX) levels were seen, whereas molecular analysis revealed a decrease in Keap1 and an increase in Nrf2 and HO-1 gene expression. Pretreatment with vitamin C and PRP prior to NaF administration significantly improved the altered parameters and enhanced the cellular antioxidant capability of myocardium resulting in protection of cardiac muscle from NaF-induced cytotoxicity and apoptotic cell death. CONCLUSIONS: The cyto-protective activity of PRP was found to be comparable to that of the known antioxidant, vitamin C.
Subject(s)
NF-E2-Related Factor 2 , Platelet-Rich Plasma , Animals , Antioxidants/pharmacology , Ascorbic Acid/pharmacology , Cardiotoxicity , Kelch-Like ECH-Associated Protein 1/metabolism , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Oxidative Stress , Platelet-Rich Plasma/metabolism , Rats , Sodium Fluoride/metabolism , Sodium Fluoride/toxicityABSTRACT
In tile present study the clinicopathological aspects of H. pylori infection in different parts of the stomach were investigated in 36 patients. The results showed that 28 patients (77.8%) were H. pylori positive and 8 patients (22.2%) were H. pylori negative by histopathology and confirmation with modified Giemsa stain. There was no statistically significant difference belween H. pylori positive and negative patients regarding dyspeptic symptoms or intestinal metaplasia histopathologically. Histopathological examination revealed chronic gastritis with mononuclear cell infiltration in all studied patients. According to the degree of cell infiltration, chronic gastritis was graded as mild, moderate and severe. There was a statistically significant difference between H. pylori positive and H. pylori negative patients regarding both severity and activity of chronic gastritis in the antrum and body compared to the fundus. Also, there was significant correlation between the grade of H. pylori colonization and the grade of chronic active gastritis on one hand and between H. pylori infection and atrophic gastritis. The serum anti-H. Pylori - IgG positive cases who were H pylori negative by history, showed atrophic gastritis acid intestinal metaplasia. This may be due to the fact that the mucosa has become inhospitable for H. pylori.
