• The Journal of Korean Academy of Prosthodontics
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• v.38 no.1
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• pp.38-49
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• 2000

The purpose of this study was to evaluate the effects of thermocycling on the shear bond strength of Co-Cr alloy to denture base resin. PMMA denture base resin such as heat-cured $Vertex-RS^{(R)}$, self-cured $Vertex-SC^{(R)}$ and 4-META denture base resin such as heat-cured $Meta-Dent^{(R)}$, self-cured $Meta-Fast^{(R)}$ was bonded to Co-Cr alloy. Samples were divided into 3 groups : no thermocycling group as control, thermocycling between $5^{\circ}C\;and\;55^{\circ}C$ with 15 second dwell time as group 1, thermocycling with 1 minute dwell time as group 2. The shear bond strength was measured and the interface between metal and resin was observed by SEM. The results were as follows. 1. The shear bond strength decreased significantly according to thermocycling and dwell time(P<0.001). 2. The bond strength of Co-Cr alloy and 4-META denture base resin was significantly higher than that of Co-Cr alloy and PMMA denture base resin(P<0.001) 3. In SEM, there was no gap in control group, but there was much and large gap in group 1, 2. The longer dwell times, the lower bond strength. PMMA denture base resin had more gap than 4-META denture base resin in the interface. These results revealed that thermocycling decreased the bond strength between Co-Cr alloy and denture base resin and dwell time of thermocycling changed the effect of thermocycling. The results suggested that oral temperature change affect the bond strength of prosthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.525-535
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• 2002

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study Samples were divided into two groups the denture base resin with chitosan, without chitosan Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows : Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan, but less bacteria adhered on them.

• The Journal of Advanced Prosthodontics
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• v.7 no.4
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• pp.278-287
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• 2015

PURPOSE. The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. RESULTS. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. CONCLUSION. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.232-243
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• 2021

Purpose: The purpose of this study was to evaluate the shear bond strength of various 3D printed denture base resins and the conventional denture base resin to various denture relining materials. Materials and Methods: For denture base materials, a heatcured (Vertex RS) and two types of 3D printed DENTCA Denture base II, NextDent^TM Base) were used. And 4 types denture relining materials (Tokuyama Rebase II fast, Kooliner, Denture Liner, Denture Liner, Lang Jet Denture Repair Kit) with different components were used. It was classified into 12 groups. Adhesion was performed between the resin base and the relining materials in accordance with ISO/TS 11405 standard. The shear bonding strength was measured, and then the adhesion interface was observed with a stereoscopic microscope and a scanning electron microscope. The fracture pattern was investigated through the analysis of the fragment. Results: In the 3D printed denture resin group, the shear bonding strength with relining materials was significantly lower than that of the heat-cured resin group (P < 0.05). The group of polymethyl methacrylate -based relining materials, high shear bonding strength was shown regardless of the type of denture. As for the fracture pattern, adhesive fracture appeared in most groups, and cohesive, mixed fracture appeared in some groups. Conclusion: The polymethyl methacrylate -based denture relining materials showed high shear bonding strength values compared to other denture relining materials. But, for direct methods, it is considered advantageous in terms of shear bonding strength to use a isobutyl methacrylate-based denture relining materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5745-5751
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• 2013

The purpose of this study was to evaluate the effect of the surface treatment of MMA and TEGDMA concentration, silane coupling agent on the shear bond strength of denture base resin and denture reliners. Denture base resin surface was treated with MMA and TEGDMA concentration, silane coupling agent. After denture reliners were injected bond strength was measured. The results of MMA and TEGDMA concentration on the shear bond strength of Vertex self curing resin showed that the value of MMA 95% and TEGDMA 5%, MMA 90% and TEGDMA 10%, MMA 80% and TEGDMA 20% groups were higher than that of other group(P<0.05). MMA and TEGDMA concentration on the shear bond strength of Kooliner resin showed that the value of MMA 95% and TEGDMA 5%, MMA 90% and TEGDMA 10% were higher than that of other group(P<0.05). Silane coupling agent on the shear bond strength of Vertex self curing resin and Kooliner showed that the value of MMA 95% and silane coupling agent 5% groups was higher than that of other group(P<0.05). Therefore, we could conclude that appropriate chemical surface treatments are supposed to affect the bond of denture base resin and denture reliners.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.3
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• pp.464-474
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• 1996

A principal advantage of a plastic tooth over a porcelain tooth should be its ability to bond to the denture base material. But plastic teeth could craze and wear easily, so more abrasion resistant plastic denture teeth have been developed. To resist abrasion, the degree of cross-linking was increased, but bonding to denture base meterial became more difficult. The purpose of this study was to evaluate the bond strength of plastic teeth and abrasion resistant teeth bonded to heat-curing, self-curing and light-curing denture base material. Denture tooth molds were chosen that had a>8mm diameter. The denture teeth was bonded to three denture base materials and then machined to the same dimensions. Three denture base materials were used as control groups. Prior to tensile testing, the specimens were thermocycled between $5^{\circ}C\;and\;55^{\circ}C$ for 1000cycles. Tensile testing was performed on an Instron Universal testing mechine. Experimental group ; plastic teeth(Justi Imperial)+heat-curing resin(Lucitone 199) plastic teeth(Justi Imperial)+light-curing resin(Triad) plastic teeth(Justi Imperial)+self-curing resin(Vertex SC) abrasion resistant teeth(IPN)+heat-curing resin(Lucitone 199) abrasion resistant teeth(IPN)+light-curing resin(Triad) abrasion resistant teeth(IPN)+self-curing resin(Vertex SC) Control group ; heat-curing resin(Lucitone 199) light-curing resin (Triad) self-curing resin(Vertex SC). The results were as follows : 1. The denture teeth bonded to heat-curing resin showed the cohesive failure and those bonded to the other resins showed adhesive failure. 2. Tensile bond strength of the plastic teeth bonded to self-curing resin was not significantly greater than bonded to light-curing resin(p>0.05). 3. Tensile bond strength of the abrasion resistant teeth bonded to self-curing resin was not significantly greater than bonded to light-curing resin(p>0.05). 4. Tensile bond strength of the plastic teeth to self-curing resin was not significantly different from that of the abrasion-resistant teeth(p>0.05). 5. Tensile bond strength of the plastic teeth to light-curing resin was significantly greater than that of the abrasion resistant teeth(p<0.01).

• Journal of Korean society of Dental Hygiene
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• v.23 no.6
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• pp.459-466
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• 2023

Objectives: The purpose of this study was to evaluate the physical properties and antibacterial activity of denture base resin with added silver sulfadiazine. Methods: Specimens were made from self-curing denture base resin and silver sulfadiazine as an inorganic antibacterial agent. For physical evaluation of the specimens, surface roughness, surface hardness, and contact angle were measured. Bacterial growth was assessed by optical densityat 600 nm (OD600) and colony forming units (CFU) measurements to confirm antibacterial activity. Results: There was no significant difference in surface roughness, surface hardness, and contact angle in the experimental group containing silver sulfadiazine compared to the control group. In contrast, the experimental group showed a significant decrease in antibacterial activity compared to the control group in terms of OD value. Analysis of CFU confirmed a significant decrease in colonies in the experimental group compared to the control group. Conclusions: Denture base resin containing silver sulfadiazine, an inorganic antibacterial agent, exhibited enhanced antibacterial activity without physical changes. In conclusion, the use of denture base resin containing inorganic antibacterial agents may be expected in the future.

• 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 Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.712-721
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• 2006

Statement of problem. Acrylic resin is most commonly used for denture bases. However, acrylic resin has week points of volumetric shrinkage during polymerization that reduces denture fit. The expandability of POSS (Polyhedral Oligomeric Silsesquioxane) containing polymer could be expected to reduce the polymerization shrinkage of denture bases and would increase the adaptability of the denture to the tissue. Purpose. The purpose of this study was to compare the dimensional stability in the conventional acrylic resin base, POSS-containing acrylic resin base, and metal bases. Materials and methods. Thirty six maxillary edentulous casts and dentures of different base were fabricated. Tooth movement and tissue contour change of denture after processing (resin curing, deflasking, decasting and finishing without polishing) and immersion in artificial saliva at $37^{\circ}C$ for 1 week and 4 weeks were measured using digital measuring microscope and threedimensional laser scanner. Results. The results were as follows: 1. The conventional resin group showed significant (p<0.01) dimensional change throughout the procedure (processing and immersion in artificial saliva). 2. After processing, the metal group and POSS resin group showed lower linear and 3-dimensional change than conventional resin group (p<0.01). 3. There was no statistically significant linear and 3-dimensional change after immersion for 1 week and 4 weeks in metal and POSS resin group. 4. In all groups, the midline and alveolar ridge crest area presented smaller 3-dimensional change compared with vestibule and posterior palatal seal area after processing and soaking in artificial saliva for 1 week and 4 weeks (p<0.01). Conclusion. In this study, a reinforced acrylic-based resin with POSS showed good dimensional stability.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.50-63
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• 1998

This study investigated the effects of resin surface primers for rebase resins on the surface texture of denture base resins by the use of scanning electron microscopy. This study also evaluated the bond strength of rebase resins to denture base resin. The denture base resin in this study was Vertex RS (Dentimex Co., Ltd., Holland). The rebase resins used were Tokuso Rebase (Tokuyama Co., Ltd., Japan), Metabase (Sun Medical Co., Ltd., Japan), New True Liner(Harry J, Bosworth Co., Ill.), and Reverse (Nissin Co., Ltd., Japan). The test samples were divided into four parts: Group 1 : Treated with primer with brush. Group 2 : Immersed in the primer for 5 seconds. Group 3 : Immersed in the primer for 10 seconds. Group 4 : Immersed in the primer for 30 seconds. Control group : not treated with primer The results were as follows; 1. The bond strength of rebase resins to denture base resin is increased by application of primers. 2. Regardless of the rebase resin type, there was no significant difference among the bond strength in groups G1, G2, G3, G4. There was a significant difference with the control. (P<0.05) 3. Regardless of each group, the bond strength according to the rebase resin type was decreased in the following order: Tokuso Rebase, New Tru Liner, Reverse and then Metabase. 4. Under the scanning electron microscope, brush application produced a softening of the denture base surface. After immersion, all primers produced a spongelike structure on the denture base resin surface. The results of this study suggest that primers produce a significant effect by means of brush application, therefore it is recommended as the most convenient and logical procedure for application of the primers.