SACM - United States of America
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9668
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Item Restricted Bond Strength of Denture Teeth to Conventional, Milled and 3D-Printed Denture Bases(Saudi Digital Library, 2025) Abumansour, Malik; Ontiveros, Joe C; Gonzalez, Maria D; Belles, Donald M; amnuay, Sudarat Kiat; amnua, Chun-YenOBJECTIVE: This in vitro study assessed the shear bond strength and failure modes between denture teeth and denture bases fabricated using conventional, two-part milled, monolithic milled, or 3D-printed complete denture techniques. MATERIALS AND METHODS:A total of 40 denture base substrates (30 mm diameter x 10 mm height) were processed according to the following material treatment groups, n=10 for all groups: (1) Conventional complete denture processed using heat-polymerized resin (Lucitone 199, Dentsply Sirona) as a control; (2) 3D-printed denture resins (Lucitone Digital IPN 3D Premium, shade A1, and Lucitone Digital Print 3D Denture Resin, Original); (3) Two-part milled dentures from pre-polymerized polymethylmethacrylate pucks (Lucitone Digital Fit Denture Base Disc, Dentsply Sirona; Multilayer PMMA Discs, Dentsply Sirona), and (4) Monolithic milling denture (AvaDent, Extreme cross-linked PMMA). For all groups, prefabricated denture teeth or bases were embedded in autopolymerizing acrylic resin, except for Group four, in which the base and teeth were fabricated as a single unit. After embedding, specimens were polished using 400-grit sandpaper to achieve uniform surface exposure. The bonding of the two parts, base and teeth, was performed according to each manufacturer’s protocol. All specimens were tested within 24 hours of bonding. Shear bond strength was measured using a universal testing machine at a crosshead speed of 1 mm/min. The mode of failure was observed and recorded. Data were analyzed using one-way ANOVA followed by Tukey post hoc test at a significance level of α = 0.05. RESULTS: The monolithic milling group demonstrated the highest bond strength among all groups, with statistically significant differences compared to the others (p < 0.01), with 100% cohesive failure. The 3D printed group exhibited a significantly higher mean bond strength than both the conventional and milled groups (p = 0.001), with 70% of mixed failure. There was no significant difference between the conventional and milled groups (p = 0.98), which represent 90% and 100% of adhesive failure, respectively. CONCLUSIONS: Among all groups, the monolithic milled dentures (AvaDent) demonstrated the highest bond strength at the base-to-tooth interface. The 3D-printed denture specimens showed greater base-to-tooth bond strengths compared to both the conventionally processed and the two-part milled dentures, which showed no significant difference from each other.18 0Item Restricted A STUDY OF THE EFFECT OF PREPARATION PARAMETERS ON THE MECHANICAL PROPERTIES OF FREEZE-DRIED GELATIN-ELASTIN-HYALURONATE SCAFFOLDS(Marquette University, 2024-05) Qamash, Mansour; Tayebi, LobatThis thesis is dedicated to a detailed study of changes in the properties of Gelatin-Elastin Hyaluronate (GEH) tissue engineering scaffold resulting from changes in preparation parameters. More specifically, utilizing a combination of foaming and freeze-drying techniques, this research investigates the effects of different parameters, including agitation speed, duration time, and chilling temperature on the scaffold’s structural integrity, porosity, and mechanical properties. The methodology involves a carefully calibrated process in which the scaffold matrix is initially prepared by incorporating 8% gelatin, 2% elastin, and 0.5% hyaluronate (w/v) into a homogenous aqueous solution, followed by controlled agitation and subsequent freezing at designated temperatures. The freeze-drying stage solidifies the foam structure, creating a porous matrix essential for cell growth and nutrient delivery. The findings reveal that porosity and mechanical properties, such as compressive Young’s modulus, of scaffolds are significantly influenced by fabrication parameters, with higher agitation speeds and longer duration times leading to increased porosity and decreased modulus. Moreover, the degradation rates of the scaffolds processed at both −20 and −80°C were found to be comparable, indicating a similar level of preservation in physiological conditions. Morphological analyses, including laser microscopy and scanning electron microscopy (SEM), indicated optimal pore sizes (100–300 µm) that promote effective cell interaction and tissue regeneration, confirming the successful application of the freeze-drying and foaming methods in creating highly interconnected porous structures. Based on the findings, a decrease in chilling temperature correlates with a slight increase in pore size within the scaffold matrix. The methodical fabrication process developed in this study emphasizes the control of agitation speed and duration to modulate scaffold porosity, which is an essential characteristic for cellular infiltration and vascularization in tissue engineering. The research outcomes demonstrate that scaffold properties can be finely adjusted through the preparation process, offering the potential to match the structural needs of specific tissue engineering applications. The thesis contributes significant advancements in scaffold design, providing a robust framework for the development of tissue scaffolds with controlled porosity and improved mechanical properties. By understanding and harnessing the effects of fabrication parameters, this research offers a pathway to design scaffolds that more accurately replicate the extracellular matrix, promoting enhanced tissue repair and regeneration.21 0