• Journal of Technologic Dentistry
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• v.44 no.4
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• pp.111-117
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• 2022

Purpose: This study was conducted to compare the Vickers hardness on the denture acrylic resins using the glaze color system. Methods: The specimens (20×2 mm) were prepared by mixing according to the manufacturer's protocols through thermal polymerization and self-polymerization. The surface roughness was measured using a testing machine after water-soaking for 48 hours. For the Vickers hardness measurement, the completed specimen was soaked in water for 48 hours and then applied at 200 gf for 30 seconds. Was the specimen immersed after being soaked in water for 48 hours at temperatures of 5℃ and 55℃, respectively, for 30 seconds for the thermos-cycling treatment, and it was carried out 5,000 times. Results: Surface roughness was higher in the more glazing group than in the control group. A significant difference was observed in all groups, except for the Retec Don 2000 and Luciton 199 groups (p<0.05). As a result of measuring the Vickers hardness, the treatment by glaze color showed slightly lower but the thermo-cycling treatment group appeared higher than control group in all. Conclusion: Therefore, the glaze color was found to affect the surface roughness and showed a significant difference. The surface glaze color showed a very high Vickers hardness after the thermo-cycling treatment, indicating that the surface-strengthening effect is greater in the oral environment.

• Journal of Technologic Dentistry
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• v.37 no.4
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• pp.205-212
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• 2015

Purpose: The objective of this study was to compare the surface roughness according to polishing process in conventional laboratory techniques used for polishing three different acrylic denture base resins. Materials and methods: Specimen preparation and surface polishing procedures were conducted to manufacturer's recommendation with three heat-polymerized denture base resins. Surface roughness and gloss were measured by a contact type tester and a LED gloss checker using thickness 2 mm and diameter 10 mm. There were five specimens for each acrylic resin material and polishing procedures. Mean average surface roughness (Ra) values of each specimen group were analyzed using a one-way ANOVA analysis of variance and Scheffe's post hoc test. Surfaces after surface roughness and gloss testing according to each polishing process were evaluated under a stereoscopic microscope. Results: The highest mean average surface roughness was measured($Ra=2.43{\pm}0.47$) for surfaces finished with a denture tungsten carbide bur in Triplex. The lowest surface roughness values ($Ra=0.11{\pm}0.07$) were determined in Vertex polished with a lathe. In addition, all materials revealed that surface roughness determined highly in HP1 and HP2 than other procedures. All correlation between surface roughness and gloss showed highly with three heat-polymerized resins. Specially, topmost correlation revealed than other material in Triplex. Significant differences in mean average surface roughness were found between polishing process used high speed lathe and low speed hand-piece. Conclusion: Laboratory polishing used to high speed was found to produce the smoothest surface of heat-polymerized denture base acrylic resin. Therefore, we recommended that high polishing process need to get smooth surface.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.1-14
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• 1997

The purpose of this study was to investigate the physical effect of tissue conditioner on polymerized acrylic resins. Surface hardness and transverse strength were measured for evaluating physical effect of tissue conditioner on polymerized acrylic resins. 1) To measured surface hardness, the resin specimens($65{\times}10{\times}10mm$ size) of each resin material were made, applied tissue conditioner, stored in $37^{\circ}C$ water for 1 week, and changed tissue conditioner every week for 3 weeks. Surface hardness was measured every week with Shore hardness tester for 4 weeks. 2) To measured transverse strength, the resin specimens($65{\times}10{\times}3mm$ size & $65{\times}10{\times}1.5mm$) of each resin material were made. The specimens were divided into four groups, and measured by universial testing machine. Group I(control group) : The resin specimens were stored in $37^{\circ}C$ water for 5 weeks. Group II : The resin specimens were stored in $37^{\circ}C$ water for 5 weeks, and relined in 1.5mm thickness with same resin. Group III : The resin specimens were stored in $37^{\circ}C$ water for 1 week, applied tissue conditioner in 1.5mm thickness, stored in $37^{\circ}C$ water for 1 week, changed tissue conditioner and water every week for 3 weeks, removed tissue conditioner, reduced 1.5mm thickness from resin surface which was applied tissue conditioner, and relined in 1.5mm thickness with same resin. The following conclusions were obtained : 1. Surface hardness changes of Vertex RS and Vertex SC were not different significantly(p>0.01). 2. Surface hardness of K-33, Tokuso rebase, and Kooliner were decreased(p<0.01). 3. With the exception of Kooliner, transverse strength of all resin materials between control group and groups which applied with tissue conditioner were not different significantly(p>0.01).

• Journal of Technologic Dentistry
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• v.35 no.2
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• pp.97-103
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• 2013

Purpose: The purpose of this study was to investigate the effect of addition of fiber glass on the physical properties of silanized fiber mesh and non silanized mesh of denture base resins. Methods: The denture base resins were used in this study heat curing acrylic resins(Vertex Rs, Lucitone 199, $20{\times}80mm$) and fiber glass(SES, Green B&D co., Ltd, $20{\times}80mm$) were used as reinforcement. The specimens were stored in distilled water at $37{\pm}2^{\circ}C$ for 72 hours before test. Bending strength and tensile strength were measured by an universal testing machine(Instron 4301, Instron Corp.). Penetration distribution on fiber was observed by scanning electron microscopy(JSM 840A, Jeol Ltd). Results: The bending strength and modulus were increased by 30% after adding fiber glass on denture base resins. Tensile strength showed significant increasing by adding fiber glass on denture base resins. Conclusion: In this study, Addition of silanized fiber in denture base resins were improved physical properties. we confirmed the fiber glass possibility of the replacement about conventional materials.

• 보존과학연구
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• s.17
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• pp.39-47
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• 1996

In this research, many effects were examined by testing of adhesive intensity and accelerated weathering with synthetic resins for the conservation treatment of cracks and damaged parts of Kyound Chun-Sa10-story Pagodas, the National Treasure No. 86.It was tested with two kinds of Epoxy resins, Acrylic, Silicone resin, and five kinds of Acetics vinyl resins, and then which was ensured a successful result with Epoxy resins. According to these consequences, they are determined to treat damaged parts with Epoxy resin.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.32-40
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• 2019

PURPOSE. The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS. In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS. For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P<.05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION. Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

• Journal of Technologic Dentistry
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• v.12 no.1
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• pp.103-106
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• 1990

The purpose of this study was to determine if homogeneity of the resin associated with benchcuring could be obtained in the curing unit as the water increased from room temperature to curing temperature. The results of the experiment were as follows : 1. Long periods of bench-curing are not necessary. 2. Bench-curing can take place in the water bath of the curing unit. When this procedure is used, the water should be far enough below the temerature at which active polymerization of the resin proceeds to allow the bench-curing to occur.

• Journal of Technologic Dentistry
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• v.9 no.1
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• pp.51-55
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• 1987

One of the primary advantages of acrylic resin teeth is their ability to bond chemically to the denture base resins. Fracture od acrylic resin teeth from a maxillary denture, however, is not uncommon. Bonding failures have been attributed to faulty boil-out procedures that fail to eliminate all traces of wax from the ridge lap surfaces of the teeth and to contamination of the ridge lap surface by careless application of tinfoil substitute. Attempts to increase the strength of the bond between acrylic resin teeth and heat-cured denture base resin include grinding the glossy ridge lap surface (in fluid system), painting the ridgelap surface of the teeth with monomer-polymer solution, and cutting retention grooves in the ridge lap surface of the teeth. This latter method has been tested by applying a tensile force in a labial direction to the incisal part of the lingual surface of the acrylic resin teeth. A progressive shear compressive load was applied at an angle to the lingual surface of acrylic resin teeth bonded to denture base acrylic resin. No statistically singificant advantage was derived by preparing retention grooves of different shapes in the ridgelap surface of the denture teeth.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.287-295
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• 2013

PURPOSE. This study investigated the effect of laser parameters and air-abrasion on the peel strength of silicon-based soft denture liner to different denture resins. MATERIALS AND METHODS. Specimens (N=180) were prepared out of three different denture base resins (Rodex, cross-linked denture base acrylic resin; Paladent, heat-cured acrylic resin; Deflex, Polyamide resin) ($75mm{\times}25mm{\times}3mm$). A silicon-based soft denture liner (Molloplast B) was applied to the denture resins after the following conditioning methods: a) Air-abrasion ($50{\mu}m$), b) Er,Cr:YSGG laser (Waterlase MD Turbo, Biolase Technology) at 2 W-20 Hz, c) Er,Cr:YSGG laser at 2 W-30 Hz, d) Er,Cr:YSGG laser at 3 W-20 Hz, e) Er,Cr:YSGG laser at 3 W-30 Hz. Non-conditioned group acted as the control group. Peel test was performed in a universal testing machine. Failure modes were evaluated visually. Data were analyzed using two-way ANOVA and Tukey's test (${\alpha}$=.05). RESULTS. Denture liner tested showed increased peel strength after laser treatment with different parameters ($3.9{\pm}0.4-5.58{\pm}0.6$ MPa) compared to the control ($3.64{\pm}0.5-4.58{\pm}0.5$ MPa) and air-abraded groups ($3.1{\pm}0.6-4.46{\pm}0.3$ MPa), but the results were not statistically significant except for Paladent, with the pretreatment of Er,Cr:YSGG laser at 3 W-20 Hz. Polyamide resin after air-abrasion showed significantly lower peel strength than those of other groups ($3.1{\pm}0.6$ MPa). CONCLUSION. Heat-cured acrylic resin, PMMA, may benefit from Er,Cr:YSGG laser treatment at 3 W-20 Hz irradiation. Air-abrasion of polyamide resins should be avoided not to impair their peel bond strengths to silicon-based soft denture liners.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.423-427
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• 2013

PURPOSE. This study evaluated the bond strength between porcelain denture teeth (Bioblend 43D) and four different polymerized denture resins (Lucitone 199, Palapress, Acron MC, Triad) with and without a bonding agent and after four different types of surface treatment (polished, HF etched, sandblasted, air-abraded). MATERIALS AND METHODS. Central incisor porcelain denture teeth were divided into 32 groups of 5 each. Tensile bond strength (MPa) was determined using a testing machine at crosshead speed of 0.5 mm/min. Mean and standard deviation are listed. Data were analyzed by two-way ANOVA. Means were compared by Tukey-Kramer intervals at 0.05 significance level. RESULTS. All surface treatment increased bond strength compared to polished surface and the highest bond strength was found with Palapress resin with etched porcelain surface (8.1 MPa). Bonding agent improved the bond strength of all denture resins to porcelain teeth. Superior bonding was found with Palapress and air-abraded porcelain (39 MPa). CONCLUSION. Resins with different curing methods affect the bond strength of porcelain teeth to denture bases. Superior bonding was found with auto-polymerized resin (Palapress). Application of ceramic primer and bonding agent to porcelain teeth with and without surface treatment will improve the bond strength of all denture resins to porcelain teeth.