Saudi Cultural Missions Theses & Dissertations
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Item Restricted Influence of diphenyliodonium hexafluorophosphate salt (DPI) and ion-releasing glass fillers (45S5) on physical, mechanical and chemical properties of model resin composite formulations(University of Manchester, 2024-07-30) Alotaibi, Saad; Silikas, Nick; Watts, DavidRecurrent dental caries is a major reason for resin composite restoration replacement. 45S5 Ion-releasing glass (IRG) fillers are promising for functionalizing resin composites. They aid in hydroxyapatite deposition and remineralization of dental tissues. Diphenyl iodonium hexafluorophosphate (DPI) is a UV light initiator that replenishes Camphorquinone (CQ) by replacing inactive radicals with phenyl active radicals. The aim of this research was to explore the interactive effect of DPI and IRG on short and long-term material properties. Model resin-composites with varying amounts of IRG were prepared using a UDMA/TEGDMA resin system and either a unary or binary (includes DPI) photo-initiator system. Polymerization related properties such as degree of conversion (DC), shrinkage strain (SS) and depth of cure (DoC) were measured. IRG negatively impacted DC and DoC when higher content was used while DPI improved both DC and DoC. The SS was lower in the unary group and with higher IRG content confirming an inverse relation between DC and SS. Martens hardness (HM) and related parameters, indentation modulus (EIT) and creep (CIT), as well as the effect of storage in water or ethanol on these parameters were tested. HM and EIT decreased and CIT increased linearly as the amount of IRG is increased. Deterioration of HM and EIT through aging was more pronounced in specimens containing higher IRG amount. DPI showed higher HM, EIT and lower CIT only at higher IRG content compared to the unary group. Water sorption, solubility, hygroscopic dimensional changes and ions release were assessed. IRG significantly increased water sorption, solubility and hygroscopic expansion. Inclusion of DPI reduced water sorption, solubility and hygroscopic expansion. Release of calcium, sodium and phosphate were dose dependent on IRG. This study concluded that 45S5 IRG, while offering potential means of remineralisation, diminished the material’s overall properties. The inclusion of DPI enhanced the polymerization and overall properties of the tested model resin composites.10 0Item Restricted EVALUATION OF STAINING, COLOR STABILITY, BLENDING EFFECT AND DEPTH OF CURE OF A NEW UNIVERSAL RESIN COMPOSITE(2023-05-12) Alalawi, Hanan; Antonson, SibelObjectives: The objective of this study was to evaluate the surface staining, color stability, blending effect, and depth of cure of a new generation resin composite. Materials and methods: Surface staining was tested using a total of 45 samples for each of the three resin composites (Tetric Prime, Filtek Supreme Ultra, and Omnichroma). Baseline spectrophotometer measurements were made before immersing into the following beverages: distilled water, cola, and coffee for 14 days. Specimens were then prepared and polished. To determine color stability, 30 resin composite specimens were prepared and measured using a spectrophotometer immediately after thermal cycling (between 5°C and 55°C), and 14 days of water storage (at 60°C). A total of 45 specimens were used to evaluate the blending effect. The evaluation was done using denture teeth (VITA Classical A1-D4 shades, SR Orthoplane DCL, LML3 Ivoclar, Amherst, NY) restored with the tested resin composites. The color difference (ΔE) values were obtained by using a spectrophotometer. The depth of cure was evaluated by using a total of 15 Typodont teeth. Preparation was created in the center of each tooth (4 x 4 mm diameter), then filled with the resin composites in single increments and photopolymerized. The surface hardness was measured using a Vickers microhardness indenter. Results: There was significantly higher staining caused by coffee compared to other solutions for all groups. Omnichroma showed the least staining in coffee solution with a significant difference compared to the other groups (p < 0.0001). Regarding color stability, there was a significant difference between Omnichroma and other resin composite groups in both water and thermal groups; Omnichroma had the least color stability. The best blending effect values were found in Omnichroma compared to other groups. None of the tested resin composites demonstrated a 4 mm depth of cure. Filtek Supreme Ultra presented better microhardness values at 0- and 0.5-mm depth. While Tetric Prime and Omnichroma showed a significantly higher percentage of polymerization from 0.5 to 3.5 mm depth. Conclusions: Omnichroma had the least surface staining and the best blending effect values. However, it had the lowest color stability. Tetric Prime and Omnichroma presented a higher percentage of polymerization than Filtek Supreme Ultra. While Filtek Supreme Ultra presented with better microhardness.15 0