• The Journal of Advanced Prosthodontics
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• v.15 no.4
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• pp.189-201
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• 2023

PURPOSE. The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils. MATERIALS AND METHODS. Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05). RESULTS. The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance. CONCLUSION. Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

• Journal of Technologic Dentistry
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• v.35 no.4
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• pp.287-293
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• 2013

Purpose: This study is to provide basic data of the dental acrylic denture base resin in the mechanical property difference investigation according to the monomer composition weight ratio of the acrylic denture base resin. Methods: The monomer composition of the acrylic denture base resin and weight ratio makes the different specimen. It measured the mechanical property with the specimens through Hardness Test, Tensile Test, Flexural Test, Flexural Modulus, FT-IR Test. Results: The control group Vertex was 18.4 Hv and the experimental group MED was 14.46~19.07Hv in the hardness test. Vertex was 364N, MED-3 was lowest in the tensile strength test and the Head of a family cursor declination was big. The result declination of the experimental specimens showed. Vertex and MED-2 was the highestest in the flexural test and after coming MED-6, MED-5, MED-1, MED-3, MED-4. Vertex and MED-2, as to a spectrum for $500{\sim}1800cm^{-1}$ peak can show the excellent degree of polymerization in the FT-IR Test. Conclusion: The ideal weight ratio of the monomer of the acrylic denture base resin of which the mechanical property is the highestest was MMA 100g, EDGMA 5g, DMA 0.2g, of MED-2.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.3
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• pp.411-436
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• 1992

The purpose of this study was to assess the adhesion of resilient denture liners (such as, heat-cured silicone molloplast B,cold- cured silicone Mollosil) to polymethyl metacrylate (K-33) and metal (Megalloy) in the laboratory by peel test. The resilient denture lines were processed according to manufactures instruction, onto prepared specimens(original resin base plate, rough resin base plate, stippled metal plate, mesh metal plate ) 75mm long and 25m wide. And then, the peel test was performed by instron. The results were as follows : 1. The bonding strength of Mollosil was stronger than that of Molloplast B except the specimen of stippled metal plate. 2. The tensile strength of Mollosil was weaker than that of Molloplast Bas tearing of Mollosil was occured in the peel test. 3. Mesh metal plate had the highest bonding strength in the case of Molloplast B and Mollosil. But stippled metal plate have high bonding strength in the case of Molloplast B and have the lowest bonding strength in the case of Mollosil. 4. The bonding strength of rough resin base plate was stronger than that of original resin base plate in the case of Molloplast B and Mollosil. 5. The bonding strength of metal plates was stronger than that of resin base plates in the case of Molloplast B and Mollosil except the case of bonding strength between the stippled metal plate and Mollosil. 6. It seems that the Increase of surface and retention form of metal plate and resin base plate produces higher physical bonding strength.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.665-674
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• 1996

This study was designed to evaluate the effect of processing method and surface design on the transverse strength of repaired denture base resin. Three heat-cured denture base resins(Vertex, Lucitone, Lang), one cold-cured resin(Lang), and one light-cured resin(Dentacolor gingiva material) were used for repair purpose. The specimens for 3-point flexure test were fabricated by five processing methods such as self-curing, pressure pot, boiling water, processing, and light curing. Finally to evaluate the effect of surface designs for repaired resin, three surface designs(butt, bevel, inverse bevel) were tested. Within the limit of this study, following conclusions were drawn. 1. Lucitone denture base material showed highest flexural strength of $131.37{\pm}2.15MPa$, and there were significant differences in stength between Lucitone and other resins. 2. Between two different self curing methods, self curing repair resin, Lang, cured by pressure pot method showed highest flexural strength, $58.49{\pm}4.89MPa$. 3. Among the heat cured repair resins, maximum transverse strength value of $88.69{\pm}16.60MPa$ was recorded in Lucitone group cured by processing method. 4. Inverse bevel joint design showed significantly higher bond strength than butt joint group, Maximum bond strength was $59.36{\pm}1.33MPa$ in inverse bevel joint design group.

• Journal of Technologic Dentistry
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• v.36 no.1
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• pp.1-7
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• 2014

Purpose: The aim of this study was analyzed by comparing the effect of glass fiber reinforcement addition on the strength of resin denture base. It was intended to provide a reference data useful for clinical application. Methods: The test specimens (length $64.0{\pm}0.1mm$, width $10.0{\pm}0.1mm$, thickness $1.0{\pm}0.1mm$, $1.5{\pm}0.1mm$, and $2.0{\pm}0.1mm$ respectively) were made. In the experimental groups resin denture base reinforced with glass fiber were fabricated. In the control groups resin denture base were fabricated by conventional method. After specimen fabrication was completed, transverse test was performed using a universal testing machine. Results: The transverse strength value in CON group was $83.08{\pm}9.07MPa$ for 1.0 mm, which ranked the highest in value. On the other hand, the value was $56.07{\pm}5.15MPa$ for 2.0mm, which ranked the lowest in value. And CON+SES group was $119.80{\pm}30.70MPa$ for 1.0mm, which ranked the highest in value. On the other hand, the value was $84.00{\pm}7.97MPa$ for 2.0mm, which ranked the lowest in value. Also, the flexural modulus value in CON group was $2,983.10{\pm}506.92MPa$ for 1.0mm, which ranked the highest in value. On the other hand, the value was $1,257.64{\pm}230.48MPa$ for 2.0mm, which ranked the lowest in value. And CON+SES group was $4,679.41{\pm}1578.29MPa$ for 1.0mm, which ranked the highest in value. On the other hand, the value was $2,512.36{\pm}527.09MPa$ for 2.0mm, which ranked the lowest in value. Conclusion: The reinforced glass fiber increased the strength of resin denture base, effected to reduce the thickness of resin denture base.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.216-227
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• 2007

Statement of problem: For the long-term success of removable partial dentures, the bonding between metal framework and denture base resin is one of the important factors. To improve bonding between those, macro-mechanical retentive form that is included metal framework design has been generally used. However it has been known that sealing at the interface between metal framework and denture base resin is very weak, because this method uses mechanical bonding. Purpose: Many studies has been made to find a simple method which induces chemical bond, now various bonding system is applied to clinic. In this experiment, shear bond strengths of heat-cured denture base resin to the surface-treated Co-Cr alloy were measured before and after thermocycling. Chemically treated groups with Alloy $Primer^{TM}$, Super-Bond $C&B^{TM}$, and tribochemically treated group with $Rocatec^{TM}$ system were compared to the beadtreated control group. The data were analyzed with two-way ANOVA. Result: 1. Shear bond strength of bead-treated group is highest, and Alloy $Primer^{TM}$ treated group, Super-Bond $C&B^{TM}$ treated group, RocatecTM system treated group were followed. Statistically significant differences were found in each treated group(p<0.05). 2. Surface treatment and thermocycling affected shear bond strength(p<0.05), however there was no interaction between two factors(p>0.05). 3. Shear bond strengths of bead-treated group and Alloy $Primer^{TM}$ treated group showed no statistically significant difference before and after thermocycling(p>0.05), and those of Super-Bond $C&B^{TM}$ treated group and $Rocatec^{TM}$ system treated group showed statistically significant difference after thermocycling(p<0.05).

• Journal of Technologic Dentistry
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• v.31 no.4
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• pp.37-43
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• 2009

This study evaluated the effect of concentration of glass fiber reinforcement on the flexural properties of auto and heat polymerized denture base resin. The test specimens($64{\times}10{\times}3.3mm$) were made of auto and heat polymerized resin(Vertex, Dentimax, Netherlands). Glass fiber(ER 270FW, Hankuk Fiber Glass, Korea) were used to reinforce the denture base resin. The 2.6%, 5.3% and 7.9% volume pre-impregnated fiber were located at the bottom of specimen. The test specimens(n=7) of each group were stored in distilled water at $37^{\circ}C$ for 50 hours before test. The flexural strength and modulus were measured by an universal testing machine(Z020, Zwick, Germany) at a crosshead speed of 5 mm/min in a three-point bending mode. The data was analyzed by one-way ANOVA and the Duncan's multiple range test(${\alpha}$=0.05). The difference of auto polymerized resin groups and heat polymerized resin groups were statistically analyzed by t-test(${\alpha}$=0.05). Glass fiber showed significant reinforcing effects on auto and heat polymerized resin. For flexural strength and modulus, auto polymerized resin was the highest in 7.9% volume, while heat polymerized resin was the highest in 5.3% volume. In this study, glass fiber at 7.9% volume ratio showed most effective reinforcing effect on auto polymerized resin and glass fiber at 5.3% volume ratio showed most effective reinforcing effect on heat polymerized resin in terms of flexural strength and flexural modulus.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.2
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• pp.160-168
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• 2000

This study evaluated the effects of four adhesive metal primers on the shear bond strength of a heat curing denture base resin(Lucitone 199) to cobalt-chromium alloy(Biosil-f). The adhesive metal primers were Cesead Opaque Primer, Metal Primer, MR Bond, and Super-Bond liquid. The metal surface primed or nonprimed was filled with the heat-curing methyl methacrylate resin. The specimens were stored in water at $37^{\circ}C$ for 24 hours and the alternately immersed in water bath at $5^{\circ}C\;and\;55^{\circ}C$ for up to 2,000 thermal cycles. Shear bond strengths were measured using UTM at a crosshead speed of 0.5mm/min. Failure surface were examined under magnifying glasses. All the primers examined improved the shear bond strength between denture base resin and cobalt-chromium alloy compared with nonprimed specimens before thermal cycling. The bond strength of Cesead Opaque Primer was greatest. And after 2,000 thermal cycles, the bond strengths between resin and cobalt-chromium alloy were decreased but the difference between thermal cycling 0 and 2,000 at Cesead Opaque primer and Metal Primer were not significant. This study indicated that Cesead Opaque Primer & Metal Primer is effective primers to obtain higher bond strength between heat cured denture base resin and cobalt-chromium alloy.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.5
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• pp.1167-1174
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• 2024

The purpose of this study was to evaluate the effects of various layer thicknesses and build angles on the flexural strength and surface roughness of repaired 3D-printed denture base resin. 3D-printed bar-shaped specimens with a 45° bevel were fabricated according to layer thickness(50 ㎛ and 100 ㎛) and build angle(0-degree, 45-degree, and 90-degree). Denture relining resin was applied to the 2 mm repair area Flexural strength was measured by a three-point bending test using a universal testing machine, and surface roughness(Ra) and surface topography were observed using a digital optical microscope at ×500 magnification. Statistical significance was analyzed using two-way ANOVA, one-way ANOVA, and Games-Howell post hoc(α = .05). Except for the 90-degree group, the group with a layer thickness of 100 ㎛ showed better flexural strength values than the group with a layer thickness of 50 ㎛(p < .05). Additionally, within the same layer thickness, the 45-degree group showed the lowest flexural strength value. The Ra values of the 0-degree and 90-degree groups, where the build angle was 45° to the layer orientation, were higher at 100 ㎛ than at 5 0 ㎛ layer thickness(p < .05), and the Ra value of the 45-degree group, where the build angle was parallel to the layer orientation, was lower than those of other build angles(p < .05). Layer thickness and build angle significantly affected the surface roughness of 3D-printed denture base resin, and the surface roughness was confirmed to be closely related to the bonding strength with denture relining resin.