No abstract available.
Denture Liners* ; Dentures*

This study was investigated to compare the staining resistance of soft denture liners. Specimens wee made of Coe-soft. Coe-Comfort, Soft-liner, Visco-gel, and were stored in 1% methyleneblue solution for 24 hours. The amounts of color change before and after treatment with mono-poly and thermocycling were measured by colorimeter(TC-6FX, Tokyo Denshoku Co. Ltd, Japan) for evaluation of staining resistance. The following conclusions were drawn from this study. 1. The staining resistance of Visco-gel was increased, but there was no changer of staining resistance in Coe-soft, Coe-comfort, and Soft-liner after treatment with monopoly. 2. The staining resistance of the Coe-comfort was the least in all soft denture liners. 3. The staining resistance of Visco-gel and Soft-liner were decreased after thermocycling.
Denture Liners* ; Dentures*

PURPOSE: The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS: For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring 64.0×10.0×3.3 mm (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS: Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P < .05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION: The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.
Denture Bases ; Denture Liners ; Denture Rebasing ; Dentures

PURPOSE: The purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time. MATERIALS AND METHODS: Polymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (alpha=0.05). RESULTS: The highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063). CONCLUSION: Immersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group.
Denture Bases* ; Denture Liners* ; Immersion ; Polymethyl Methacrylate ; Silicones

STATEMENT OF PROBLEM: The failure of adhesion between the resilient denture liner and the denture base is a serious problem in clinic. PURPOSE: The PURPOSE of this study was to evaluate the effect of denture base resin surface pretreatments (mechanical and/or chemical) on the tensile bond strength between a resilient liner and processed denture resin. MATERIAL AND METHOD: Acrylic-based resilient liners (Soft liner; GC co., Japan & Coe-Soft; GC America Inc. USA) and silicone-based resilient liners (Mucosoft; Parkell Inc., USA & Dentusil; Bosworth co., USA) were used. Specimens in each soft lining material were divided two groups with or without mechanical pretreatment. Each denture base specimen received 1 of 4 chemical pretreatments including: (1) no treatment, (2) 30-s acetone treatment, (3) 15-s methylene chloride treatment, (4) 180-s methyl methacrylate treatment. All specimens were thermocycled and placed under tension until failure in a universal testing machine. RESULTS: 1. Silicone-based resilient liners exhibited significantly higher tensile bond strengths than acrylicbased resilient liners (P<.05). 2. Grinding the denture base resin improved tensile bond strengths of silicone-based resilient liners, but reduced tensile bond strengths of acrylic-based resilient liners (P<.05). 3. In acrylic-based resilient liners, treating with acetone significantly increased the bond strength of Soft liner and treating with methyl methacrylate significantly increased the bond strength of Coe-Soft (P<.05). However they were not effective compared to silicone-based resilient liner. 4. In silicone-based resilient liners, treating with all chemical etchants significantly increased the bond strength of Mucosoft to denture base, and treating with methylene chloride and methyl methacrylate increased the bond strength of Dentusil to denture base (P<.05). CONCLUSION: Although chemical and mechanical pretreatments were not effective on tensile bond strength of acrylic-based resilent liner to denture base, treating the denture base resin surface with appropriate chemical etchants after mechanical pretreatment significantly increased the tensile bond strength of silicone-based resilient liner to denture base.
Acetone ; Americas ; Denture Bases* ; Denture Liners ; Dentures* ; Japan ; Methylene Chloride

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) (75 mm x 25 mm x 3 mm). A silicon-based soft denture liner (Molloplast B) was applied to the denture resins after the following conditioning methods: a) Air-abrasion (50 microm), 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+/-0.4 - 5.58+/-0.6 MPa) compared to the control (3.64+/-0.5 - 4.58+/-0.5 MPa) and air-abraded groups (3.1+/-0.6 - 4.46+/-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+/-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.
Collodion ; Denture Bases ; Denture Liners ; Dentures ; Nylons ; Polymethyl Methacrylate

For many years permanent soft denture liners has been widely used in dental practice directly or indirectly because of its function in absorbing and distributing the impact force. However, it reveals problems such as lack of permanency and decreased bond strength in long term use. The purpose of this study is to measure the bond strength and failure between denture base resin and several permanent liners. Lucitone 199 was used as denture base resin with soft acrylic liners (Triad, Tokuso Rebase) and silicone elastomers (Tokuyama, Ufi Gel C) bonded to measure the tensile strength before and after thermocycling. The thermocycling was done in 2000 cycles at 5degrees C, 26degrees C and 55degrees C and the measured tensile strength values before and after thermocycling were compared. The mode of failure was investigated in the separated specimens. The results are as follows. 1. As to tensile strength, the strongest material is Tokuso Rebase followed by Triad, Tokuyama, Ufi Gel C in before thermocycling and the order of Triad, Tokuso Rebase, Tokuyama, Ufi Gel C in after thermocycling state. There was significant difference between the values of Triad, Tokuso Rebase and Tokuyama, Ufi Gel C(p<0.05). 2. As to degree of displacement, Ufi Gel C showed most displacement with or without thermocycling treatment and also the difference was significant with the other materials(p<0.05). 3. As to comparisons before and after thermocycling, Tokuso Rebase and Tokuyama showed significant difference in bond strength, whereas Triad and Tokuso Rebase showed significant difference in the degree of displacement(p<0.05). 4. In debonded specimens, Triad and Ufi Gel C showed adhesion failure and Tokuyama showed cohesion failure. Both failures were observed in Tokuso Rebase with adhesion failure up to 70%. The results of this study showed that degree of bond strength between permanent soft denture liner and denture base resin were variable. There was a significant difference between soft acrylics and silicone elastomers with regard to bond strength. Further research in improving bond strength of widely used silicone elastomers and in developing the method of measuring bond strength between denture base resin and the lining materials is needed.
Denture Bases* ; Denture Liners* ; Dentures* ; Silicone Elastomers ; Tensile Strength

Soft denture liners or conditioners may be valuable therapeutic materials. The life of these liners is short and varies, but it can be extended by the use of a mono-poly(polymethyl methacrylate coating material). This study determined whether coating three temporary soft denture liners with mono-poly affected the resiliency of soft liners, and evaluated the ability of mono-poly to prevent water absorption and alcohol loss from the underlying soft liners. 20x12mm cylindrical specimens of Coe-Soft, Soft-Liner, Coe-Comfort soft lining materials were made and divided into two groups of mono-poly uncoated(control) and mono-poly coated specimens. Specimens were immersed in water and compressed on an instron universal testing machine and weighted at initial, 24 hours, 1 week, 2 weeks, and 4 weeks. resiliency was determined by measuring the energy absorbed by the soft liners when stressed to a specific yield point. Mono-poly coating significantly increased the resiliency of the Soft-Liner, but had no effect on the other soft liners. Among the 3 soft liners, Soft-Liner showed the hightest resiliency and modulus of elasticity. The weight loss in Soft-Liner was the least among the 3 liners, and the weight loss in Coe-Soft was decreased by monopoly coating.
Absorption ; Denture Liners* ; Dentures* ; Elastic Modulus ; Water ; Weight Loss

For the improvement of denture fitness of changed residual ridge, denture liner can be used. Denture liner should be very stable physically in various environments of the mouth as well as be bonded strongly with denture resin. In this study, the specimens bonded with four kinds of soft denture liner and three kinds of hard denture liner were used to test the physical properties of the liners. All experimental groups were stored in 37+/-1degrees C distilled water for 24hours, followed by thermocycling between 15degrees C and 45degrees C with 15 second dwell time. 1000, 2000, 3000 cycles of thermocycling were excuted and physical properties were measured by Instron Universal Testing Machine. The obtained results were as follows: 1. In tensile bond test of soft liners, it was shown that both of Molloplast-B(R) specimens before and after thermocycling had the highest tensile strength, and in case of hard liners, Dura-liner II(R)speimen had the highest tensile strength before and after thermocycling. Depending on thermocycling, Soft-Relining(R), Denture-Relining(R),Molloplast-B(R), Coe-soft(R) and Kooliner(R) specimen showed significant difference(p<0.05). 2. In strain test of soft liners, it was shown that Molloplast-B(R) specimen before thermocycling and the Coe-soft(R) after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) speimen before and after thermocycling had the highest result. Depending on thermocycling. Denture-Relinig(R). Molloplast-B(R) and Dura-Lner II(R) specimen showed significant difference(p<0.05). 3. In Maximum distance test of soft liners, the Molloplast-B(R) specimen before thermocycling and the Coe-soft(R) after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) specimen before and after thermocycling showed highest results. Depending on thermocycling, Denture-Relining(R), Molloplast-B(R) specimens showed significant difference(p<0.05). 4.In elasticity test of soft liners , the Molloplast-B(R) specimen before and after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) specimen before thermocycling and the Tokuso-Rebase (R) after thermocycling showed highest results. Depending on thermocycling, Soft-Relining(R) , Molloplast-B(R) specimens showed significant difference(p<0.05).
Denture Liners* ; Dentures* ; Elasticity ; Mouth ; Tensile Strength ; Water

This study was performed to evaluate the tensile bond strength and modulus of elasticity of three permanent soft denture liners (Molloplast B , Ufi Gel C , Tokuyama ) before and after thermocycling. And their water sorption were also evaluated. Each soft denture liner was bonded to PMMA denture base resin blocks and the tensile bond strength and modulus of elasticity were measured by using universal testing machine. For the water sorption, weight measured after immersion of soft denture liners in 37+/-1degrees C water bath for 4 weeks. The results were as follows : 1. Molloplast B had the highest tensile bond strength, while Tokuyama had the lowest tensile bond strength, There was no significant difference between Tokuyama and Molloplast B in the both nonthermocycling and thermocycling. There was significant difference in tensile strength of Tokuyama before and after thermocycling(p<0.05). 2. For the modulus of elasticity, there was no significant difference between Ufi Gel C and Tokuyama in the both nonthermocycling and thermocycling. There was significant difference in modulus of elasticity of Tokuyama before and after thermocycling(p<0.05). 3. The failure modes of Molloplast B and Ufi Gel C were nainley adhesive type and that of Tokuyama was mainly mixed type in case of nonthermocycling and cohesive type after thermocycling. 4. The water sorption of each soft liners was within+/-2% in times (p<0.05) but, there was no significant difference among the soft liners in times.
Adhesives ; Baths ; Denture Bases ; Denture Liners* ; Dentures* ; Elastic Modulus ; Immersion ; Polymethyl Methacrylate ; Tensile Strength ; Water