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Aune Raustia - One of the best experts on this subject based on the ideXlab platform.
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flexural and surface properties of pmma denture Base Material modified with thymoquinone as an antifungal agent
Journal of Prosthodontics, 2020Co-Authors: Ahmad M Althobity, Shaimaa M Fouda, Ritva Napankangas, Aune RaustiaAbstract:PURPOSE: To evaluate the effect of addition of different concentrations of thymoquinone (TQ) on the flexural strength, elastic modulus, surface roughness, and hardness of PMMA denture Base Material. MaterialS AND METHODS: A total of 160 rectangular specimens were prepared from heat-polymerized acrylic resin, with dimensions of 65 × 10 × 2.5 mm3 for flexural strength testing and 10 × 20 × 3 mm3 for surface property testing. The specimens were divided into eight groups of 20 specimens: one control group without addition of TQ and seven test groups prepared by adding TQ to acrylic powder in concentrations of 0.5, 1, 1.5, 2, 2.5, 3, and 5 wt%. The polymer was added to the monomer before being mixed, packed, and processed using the conventional water bath method. A universal testing machine was used to measure flexural strength and elastic modulus. A profilometer and a Vickers hardness tester were used to measure surface roughness and hardness, respectively. One-way ANOVA and the Tukey-Kramer multiple-comparison test were used for statistical analysis, with statistical significance at p ≤ 0.05. RESULTS: Addition of TQ to PMMA denture Base Material significantly decreased flexural strength and elastic modulus at high concentrations (p < 0.01), while no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. At high TQ concentrations, surface roughness increased while hardness decreased (p < 0.0001), and no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. The most favorable addition values were 0.5% and 1% TQ in all TQ groups. CONCLUSIONS: Addition of TQ did not affect the flexural and surface properties of PMMA denture Base Material at low concentrations (0.5%, 1% TQ) and could be incorporated into PMMA denture Base Material as an antifungal agent.
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the effect of nanodiamonds on candida albicans adhesion and surface characteristics of pmma denture Base Material an in vitro study
Journal of Applied Oral Science, 2019Co-Authors: Shaimaa M Fouda, Ahmad M Althobity, Passent Ellakany, Fahad A Alharbi, Jorma I Virtanen, Aune RaustiaAbstract:: Candida albicans is the main causative pathogen of denture stomatitis, which affects many complete denture patients. OBJECTIVE: To evaluate the effect of different concentrations of nanodiamonds (NDs) added to polymethyl methacrylate (PMMA) denture Base Material on Candida albicans adhesion as well as on surface roughness and contact angle. METHODOLOGY: Acrylic resin specimens sized 10×10×3 mm3 were prepared and divided into four groups (n=30) according to ND concentration (0%, 0.5%, 1%, 1.5% by wt). Surface roughness was measured with a profilometer, and the contact angle with a goniometer. The effect of NDs on Candida albicans adhesion was evaluated using two methods: 1) slide count and 2) direct culture test. Analysis of variance (ANOVA) and Tukey's post hoc test were used in the statistical analyses. RESULTS: Addition of NDs decreased the Candida albicans count significantly more than in the control group (p<0.05), with a lowest of 1% NDs. Addition of NDs also significantly decreased the surface roughness (p<0.05), but the contact angle remained the same. Incorporation of NDs into the PMMA denture Base Material effectively reduced Candida albicans adhesion and decreased surface roughness. CONCLUSION: PMMA/NDs composites could be valuable in the prevention of denture stomatitis, which is considered one of the most common clinical problems among removable denture wearers.
Ahmad M Althobity - One of the best experts on this subject based on the ideXlab platform.
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flexural and surface properties of pmma denture Base Material modified with thymoquinone as an antifungal agent
Journal of Prosthodontics, 2020Co-Authors: Ahmad M Althobity, Shaimaa M Fouda, Ritva Napankangas, Aune RaustiaAbstract:PURPOSE: To evaluate the effect of addition of different concentrations of thymoquinone (TQ) on the flexural strength, elastic modulus, surface roughness, and hardness of PMMA denture Base Material. MaterialS AND METHODS: A total of 160 rectangular specimens were prepared from heat-polymerized acrylic resin, with dimensions of 65 × 10 × 2.5 mm3 for flexural strength testing and 10 × 20 × 3 mm3 for surface property testing. The specimens were divided into eight groups of 20 specimens: one control group without addition of TQ and seven test groups prepared by adding TQ to acrylic powder in concentrations of 0.5, 1, 1.5, 2, 2.5, 3, and 5 wt%. The polymer was added to the monomer before being mixed, packed, and processed using the conventional water bath method. A universal testing machine was used to measure flexural strength and elastic modulus. A profilometer and a Vickers hardness tester were used to measure surface roughness and hardness, respectively. One-way ANOVA and the Tukey-Kramer multiple-comparison test were used for statistical analysis, with statistical significance at p ≤ 0.05. RESULTS: Addition of TQ to PMMA denture Base Material significantly decreased flexural strength and elastic modulus at high concentrations (p < 0.01), while no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. At high TQ concentrations, surface roughness increased while hardness decreased (p < 0.0001), and no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. The most favorable addition values were 0.5% and 1% TQ in all TQ groups. CONCLUSIONS: Addition of TQ did not affect the flexural and surface properties of PMMA denture Base Material at low concentrations (0.5%, 1% TQ) and could be incorporated into PMMA denture Base Material as an antifungal agent.
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the effect of nanodiamonds on candida albicans adhesion and surface characteristics of pmma denture Base Material an in vitro study
Journal of Applied Oral Science, 2019Co-Authors: Shaimaa M Fouda, Ahmad M Althobity, Passent Ellakany, Fahad A Alharbi, Jorma I Virtanen, Aune RaustiaAbstract:: Candida albicans is the main causative pathogen of denture stomatitis, which affects many complete denture patients. OBJECTIVE: To evaluate the effect of different concentrations of nanodiamonds (NDs) added to polymethyl methacrylate (PMMA) denture Base Material on Candida albicans adhesion as well as on surface roughness and contact angle. METHODOLOGY: Acrylic resin specimens sized 10×10×3 mm3 were prepared and divided into four groups (n=30) according to ND concentration (0%, 0.5%, 1%, 1.5% by wt). Surface roughness was measured with a profilometer, and the contact angle with a goniometer. The effect of NDs on Candida albicans adhesion was evaluated using two methods: 1) slide count and 2) direct culture test. Analysis of variance (ANOVA) and Tukey's post hoc test were used in the statistical analyses. RESULTS: Addition of NDs decreased the Candida albicans count significantly more than in the control group (p<0.05), with a lowest of 1% NDs. Addition of NDs also significantly decreased the surface roughness (p<0.05), but the contact angle remained the same. Incorporation of NDs into the PMMA denture Base Material effectively reduced Candida albicans adhesion and decreased surface roughness. CONCLUSION: PMMA/NDs composites could be valuable in the prevention of denture stomatitis, which is considered one of the most common clinical problems among removable denture wearers.
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effect of polymerization technique and glass fiber addition on the surface roughness and hardness of pmma denture Base Material
Dental Materials Journal, 2018Co-Authors: Ahmed Rahoma, Ahmad M AlthobityAbstract:: The current study evaluated the effects of autoclave polymerization both with and without glass fiber (GF) reinforcement on the surface roughness and hardness of acrylic denture Base Material. Ninety disc specimens (30×2.5 mm) were prepared from Vertex resin and divided according to polymerization techniques into a water bath, short and long autoclave polymerization groups. Tested groups were divided into three subgroups according to the GF concentration (0, 2.5, and 5 wt%). Profilometer and Vickers hardness tests were performed to measure surface roughness and hardness. ANOVA and Tukey-Kramer multiple comparison tests analyzed the results, and p≤0.05 was considered statistically significant. Autoclave polymerization significantly decreased the surface roughness and increased the hardness of acrylic resin without GF reinforcement (p<0.05). However, 5 wt% GF addition significantly increased surface roughness and decreased hardness of the autoclave polymerized denture Base resin (p<0.05). Surface properties of Polymethyl methacrylate (PMMA) denture Base Material improved with autoclave polymerization and negatively affected with GFs addition.
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effect of zirconium oxide nanoparticles addition on the optical and tensile properties of polymethyl methacrylate denture Base Material
International Journal of Nanomedicine, 2018Co-Authors: Reem Abualsaud, Ahmad M Althobity, Ahmed Rahoma, Khalid S Alabidi, Sultan AkhtarAbstract:Background: Polymethyl methacrylate (PMMA) is widely used for the fabrication of removable prostheses. Recently, zirconium oxide nanoparticles (nano-ZrO2) have been added to improve some properties of PMMA, but their effect on the optical properties and tensile strength are neglected. Objective: The aim of this study was to investigate the effect of nano-ZrO2 addition on the translucency and tensile strength of the PMMA denture Base Material. Materials and methods: Eighty specimens (40 dumbbell-shaped and 40 discs) were prepared out of heat-polymerized acrylic resin and divided into four groups per test (n=10). The control group for each test included unreinforced acrylic, while the test groups were reinforced with 2.5, 5, and 7.5 wt% nano-ZrO2. Acrylic resin was mixed according to manufacturer's instructions, packed, and processed by conventional method. After polymerization, all specimens were finished, polished, and stored in distilled water at 37°C for 48±2 hours. Tensile strength (MPa) was evaluated using the universal testing machine while the specimens' translucency was examined using a spectrophotometer. Statistical analysis was carried out by SPSS using the paired sample t-test (p≤0.05). A scanning electron microscope was used to analyze the morphological changes and topography of the fractured surfaces. Results: This study showed that the mean tensile strength of the PMMA in the test groups of 2.5%NZ, 5%NZ, and 7.5%NZ was significantly higher than the control group. The tensile strength increased significantly after nano-ZrO2 addition, and the maximum increase seen was in the 7.5%NZ group. The translucency values of the experimental groups were significantly lower than those of the control group. Within the reinforced groups, the 2.5%NZ group had significantly higher translucency values when compared to the 5%NZ and 7.5%NZ groups. Conclusion: The addition of nano-ZrO2 increased the tensile strength of the denture Base acrylic. The increase was directly proportional to the nano-ZrO2 concentration. The translucency of the PMMA was reduced as the nano-ZrO2 increased. Clinical significance: Based on the results of the current study, the tensile strength was improved with different percentages of nano-ZrO2 additions. However, translucency was adversely affected. Therefore, it is important to determine the appropriate amount of reinforcing nano-ZrO2 that will create a balance between achieved properties - mechanical and optical.
Kusai Baroudi - One of the best experts on this subject based on the ideXlab platform.
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effect of silver nanoparticles incorporation on viscoelastic properties of acrylic resin denture Base Material
European Journal of Dentistry, 2015Co-Authors: Hamada Zaki Mahross, Kusai BaroudiAbstract:Objective: The objective was to investigate the effect of silver nanoparticles (AgNPs) incorporation on viscoelastic properties of acrylic resin denture Base Material. Materials and Methods: A total of 20 specimens (60 × 10 × 2 mm) of heat cured acrylic resin were constructed and divided into four groups (five for each), according to the concentration of AgNPs (1%, 2%, and 5% vol.) which incorporated into the liquid of acrylic resin Material and one group without additives (control group). The dynamic viscoelastic test for the test specimens was performed using the computerized Material testing system. The resulting deflection curves were analyzed by Material testing software NEXYGEN MT. Results: The 5% nanoparticles of silver (NAg) had significantly highest mean storage modulus E' and loss tangent Tan δ values followed by 2% NAg ( P P > 0.05). Conclusion: The AgNPs incorporation within the acrylic denture Base Material can improve its viscoelastic properties.
Gülçin Akca - One of the best experts on this subject based on the ideXlab platform.
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Examination of 2-methacryloyloxyethyl phosphorylcholine polymer coated acrylic resin denture Base Material: surface characteristics and Candida albicans adhesion
Journal of Materials Science: Materials in Medicine, 2018Co-Authors: İrem Türkcan, A. Dilek Nalbant, Gülçin AkcaAbstract:The aim of this study is to evaluate the effects of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer coating with various concentrations onto acrylic resin denture Base Material on surface characteristics such as contact angle and surface roughness and on Candida albicans adhesion which is the major factor of denture stomatitis. Specimens, prepared from heat-polymerized acrylic denture Base Material, were divided into control and three test groups, randomly. Surfaces of the specimens in test groups were coated with poly(MPC) (PMPC) by graft polymerization of MPC in different concentrations (0.25 mol/L; 0.50 mol/L and 0.75 mol/L), while no surface treatment was applied to the control group. Contact angles and surface roughness were examined, and chemical composition of the surfaces was analyzed by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (FTIR) to verify the presence of PMPC coatings. Then, specimens were incubated with C. albicans for 18 h and the number of adhered cells was determined. Upon PMPC coating, the contact angle values statistically decreased, but no difference was found in surface roughness values. A statistically significant decrease was observed in C. albicans adhesion in parallel with the increase in the MPC polymer concentration. There was no significant difference between 0.50 mol/L and 0.75 mol/L groups in terms of adhesion. These findings indicated that graft polymerization of MPC on acrylic denture Base Material reduces the adhesion of C. albicans , and may be evaluated as a coating for prevention of denture stomatitis.
Pekka K Vallittu - One of the best experts on this subject based on the ideXlab platform.
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effect of cellulose nanofiber content on flexural properties of a model thermoplastic injection molded polymethyl methacrylate denture Base Material
Journal of The Mechanical Behavior of Biomedical Materials, 2020Co-Authors: Yutaka Takahashi, Lippo V J Lassila, Tomohiro Kawaguchi, Hirono Baba, Shu Tashiro, Ippei Hamanaka, Pekka K VallittuAbstract:Abstract Cellulose nanofiber (CNF) made from wood-derived fiber is considered as a potential alternative reinforcing Material to conventional fibers. The aim of this study was to investigate the effect of CNF on the flexural properties of CNF-reinforced, injection molded, polymethyl methacrylate (PMMA) denture Base Material. Test specimens were fabricated from a model thermoplastic denture Base resin using the injection molding technique. The resin pellets were mixed with CNF (to obtain different weight percentages 5, 10, 15, and 23 wt%). PMMA without CNF served as the control (0 wt%). Prior to the testing, the test specimens (n = 12/group) were water-immersed at 37 °C water for 50 h. The flexural strengths and moduli of the specimens were determined using three-point bending tests. Statistical evaluation included a one-way analysis of variance and the Student-Newman-Keuls test (α = 0.05). The mean and standard deviation of flexural strengths with the addition of 0, 5, 10, 15 and 23% CNF were 49.4 (±0.7), 56.4 (±1.3), 63.5 (±2.0), 72.0 (±4.7), and 96.8 (±4.0) MPa, respectively. The mean and standard deviation of flexural modulus with the addition of the same concentrations of CNF were 1.31 (±0.02), 1.56 (±0.05), 1.99 (±0.14), 2.40 (±0.15), and 3.96 (±0.08) GPa, respectively. The flexural strengths and moduli of the CNF-reinforced PMMA were significantly higher than those of pure PMMA (p
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effect of rigid rod polymer filler on mechanical properties of poly methyl methacrylate denture Base Material
Dental Materials, 2008Co-Authors: Annemaria Vuorinen, Scott R Dyer, Lippo V J Lassila, Pekka K VallittuAbstract:Abstract Objectives The aim of this study was to evaluate the mechanical properties of denture Base Material with rigid rod polymer (RRP) particulate fillers. Methods Specimens were fabricated from autopolymerized polymethylmethacrylate denture Base resin (Palapress Heraus-Kulzer) and RRP particles were used as fillers (Parmax Mississippi Polymer Technologies, Inc.). Five groups were tested: 0 wt% RRP, 10 wt% RRP, 20 wt% RRP, 30 wt% RRP, and 100 wt% RRP. Specimens were stored dry at room temperature for 2 days or in water at 37 °C for 44 days before testing until failure at a three point bending test (ISO 1567) for measuring flexural properties. The surface microhardness, water sorption, and solubility were also measured. Existence of interpenetrating polymer network (IPN) between filler and denture resin was examined using solvent treatment and scanning electron microscopy (SEM). Results Specimens with RRP filler revealed higher flexural modulus, but the flexural strength decreased. Specimens with 30% RRP filler showed flexural strength of 67.4 MPa, whereas specimens without fillers gave strength of 93.9 MPa. The 100% RRP group revealed the highest flexural strength (305 MPa). Flexural strength of water-stored test specimens decreased in most groups when compared to dry specimens. Microhardness increased as a function of RRP filler. SEM micrographs revealed no IPN-network on the surface of RRP fillers. Addition of RRP fillers decreased the water sorption, whereas solubility was not affected. Significance This study revealed that although RRP polymer has good mechanical properties, addition of RRP to denture Base resin as fillers did not increase mechanical properties. This was explained by lack of IPN-formation between RRP fillers and polymer matrix.
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bonding of resin teeth to the polymethyl methacrylate denture Base Material
Acta Odontologica Scandinavica, 1995Co-Authors: Pekka K VallittuAbstract:The objective of this study was to compare bonding of acrylic resin teeth treated in various ways to the polymethyl methacrylate (PMMA) denture Base Material. The joint surface of each acrylic tooth cured to heat-cured or autopolymerizing PMMA was either untreated, ground, or adjusted with mechanical retention. The bond to the PMMA was tested with a three-point loading test. To determine whether the bond failure was adhesive or cohesive, the fracture surfaces were analyzed visually and by scanning electron microscopy. The highest bond strength to both the heat-cured and the autopolymerizing PMMA was obtained by grinding grooves on the joint surface of an acrylic resin tooth before it was cured to the PMMA (p 0.05).