Surface Of Denture Base Resin Research Articles

The Effect of Various Surface Treatment on the New Digitally Manufactured Materials Versus the Conventional Materials – In Vitro Study

Background: Clinical benefits of resilient denture liners have been recognized in prosthodontic practice for many years. The elastic behavior of the soft lining materials is designed to distribute functional and non-functional stress on denture-supporting tissues. Materials and Methods: A total of 30 dumbbell-shaped test specimens were prepared from two different heat cure denture base materials. They are divided into two groups. Group (A) was prepared from heat cure poly-methylmethacrylate resin (PMMA) and Group (B) was prepared from computeraided design and computer-aided manufacturing (CAD/CAM) acrylic resin denture base material. A temporary soft-liner type was used. The denture base specimens of (Group A and Group B) were subdivided equally into three subgroups. 3 mm was marked and sectioned on the specimens with fissure burs and removed to create a uniform space for the application of soft liner. The interface surface of each specimen and the denture base resin surface were conditioned by three surface treatment modalities: 1 – specimens were polished using silicone carbide papers of grit size, 2 – using air abrasion by 50 μm aluminum oxide particle, 3 – by application of 3 M Scotchbond dental adhesive. Tensile bond strength (TBS) was tested for the specimens of each subgroup after thermocycling. Results: The mean of TBS of subgroup (A3) and subgroup (B3) specimens treated with 3M Scotch bond was significantly higher than the other subgroups. Conclusion: The surface treatment of PMMA and CAD/CAM denture base specimens with primer followed using an adhesive bond of 3M Scotch bond had an effective and superior TBS.

Comparison of antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against Candida albicans adherent to acrylic denture base resin: An in vitro study.

One of the main factors responsible for the development of Candida albicans on the surface of denture is improper maintenance of dentures. Denture hygiene can be achieved by regular cleansing of dentures using an appropriate denture cleanser. The aim of the study is to evaluate the antifungal efficacy of commercially available denture cleanser and the extract of Turbinaria conoides seaweed against C. albicans adherent to the surface of denture base resin. This was an in vitro experimental study. Twenty-four Acrylic resin samples of dimension 10-mm radius and 2-mm thickness was randomly divided into two groups. The denture base resin was coated with C. albicans. The colonies present on the surface of each denture base resin were evaluated by serial dilution method. Group A was treated with commercially available denture cleanser and Group B was treated with extract of seaweed T. conoides. The colonies were then evaluated using serial dilution. The colony count values obtained by serial dilution were tabulated. These values were statistically analysed using t-test. Reduction of colony count is more in T. conoides than commercially available Fittydent; the difference was statistically significant with a mean difference of 65 at dilution 10-2 and 29.25 at dilution 10-3 using t-test with P < 0.001. Within the limitations of this in vitro study, it was proved that the extract of T. conoides seaweed and commercially available denture cleanser Fittydent was effective in reducing the colony count of C. albicans. T. conoides seaweed is statistically significant than commercially available Fittydent.

Evaluating Polishability of Zirconia Impregnated PMMA Nanocomposite for Denture Base Application

Artificial biomaterials are being developed for use in denture base with symmetrical properties to restore the aesthetics and functionalities. The rough surface of denture base resin promotes the adhesion of microorganisms and plaque accumulation. This study aimed to explore the consequences of polishing times on the surface roughness of high-impact (HI) heat-polymerized PMMA denture base acrylic resin reinforced with zirconia nanoparticles (nanocomposite). Thirty specimens (25 ± 0.50 mm in diameter and 2 ± 0.10 mm thickness) were fabricated from HI PMMA by adding zirconia nanoparticles at different concentrations of (0 wt.%, 1.5 wt.%, 3 wt.%, 5 wt.%, 7 wt.%, and 10 wt.%). Specimens were divided into six groups (n = 5) and surface roughness (Ra) was measured before and after polishing with a standard protocol for one and two minutes. The addition of zirconia in PMMA at low concentrations (1.5 wt.%, 3 wt.%, and 5 wt.%) did not negatively affect the surface finish of the denture base composites following conventional polishing and remained below the clinically acceptable limit (0.2 µm). After one minute of polishing, only the 10 wt.% zirconia (0.17 ± 0.03 µm) demonstrated a substantial rise in median surface roughness, in comparison with the control group (0.11 ± 0.01 µm). It is concluded that the group containing 3 wt.% (0.10 ± 0.01 µm) of zirconia is the optimum concentration to obtain the best symmetrical surface finish after two minutes of polishing.

Effects of trimethylsilane plasma coating on the hydrophobicity of denture base resin and adhesion of Candida albicans on resin surfaces

Statement of problemCandida-associated denture stomatitis is the most common oral mucosal lesion among denture wearers. Trimethylsilane (TMS) plasma coating may inhibit the growth of Candida albicans on denture surfaces. PurposeThe purpose of this in vitro study was to investigate whether TMS plasma coatings can effectively reduce C albicans adhesion on denture base acrylic resin surfaces. Material and methodsSixty denture base acrylic resin disks with smooth and rough surfaces were prepared and were either left untreated (control group) or coated with TMS monomer (experimental group) by using plasma. Contact angles were measured immediately after TMS plasma coating. The morphology of C albicans adhesion was observed with scanning electron microscopy (SEM). Energy-dispersive spectroscopy (EDS) was used to characterize the elemental composition of the specimen surface. An adhesion test was performed by incubating the resin disk specimens in C albicans suspensions (1×107 cells/mL) at 37°C for 24 hours and further measuring the optical density of the C albicans by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay test. One-way ANOVA and 2-way ANOVA were followed by a post hoc test analysis (α=.05). ResultsThe group with TMS coating exhibited a more hydrophobic surface than the control group. EDS analysis revealed successful TMS plasma coating. The difference in the mean contact angles between the uncoated group and the TMS-coated group was statistically significant (P<.05), 79.0 ±2.9 degrees versus 105.7 ±1.5 degrees for the smooth surface and 90.2 ±7.6 degrees versus 131.5 ±2.1 degrees for the rough surface. In SEM analysis, the C albicans biofilm was found to grow more on the surface of the denture base resin without the TMS coating than on the surfaces of the experimental group. In the adhesion test, the amount of C albicans adhering to the surface of denture base resin with the TMS coating was significantly less than that on the surfaces without TMS coating (P<.05). ConclusionsTMS coating significantly reduced the adhesion of C albicans to the denture base resin and may reduce denture stomatitis.

Comparative Study on Tensile bond Strength between Heat curing Denture base Resin and Reline Materials

Background/Objectives: The purpose of this study was to evaluate the effect of the chemical surface treatment on the tensile bond strength of heat curing denture base resin and reliners. Methods/Statistical Analysis: The resin used for producing the sample was heat curing resin, while for the liner, two types of self-curing resins, two types of hard liners and two types of soft liners were used. Denture base resin surface was treated with MMA 95% and TEGDMA 5%, MMA 95% and silane coupling agent 5%, heat curing resin monomer. After denture reliners were injected, tensile bond strength was measured. Findings: When analyzed by manufacturer, for repair resin, Lang had a higher tensile bond strength than Vertex SC in all experiment groups (p<0.05). For hard liner, Kooliner was higher than Rebase in all experiment groups (p<0.05). For soft liners, Dura base had a higher tensile bond strength than Coe-soft in all experiment groups (p<0.05). As such, it is assumed that the chemical treatment of surfaces between the denture base resin and each of the liners affects the tensile bond strength, and that MPS intermediates the adhesion between the organic and inorganic matter to increase the bonding. Therefore, chemical treatment of the surface using TEGDMA and MPS, as well as heat curing resin monomer is effective in improving the tensile bond strength. Among them, chemical surface treatment using MPS and heat curing resin monomer appeared to be the most effective. Improvements/Applications: After, in order to increase the bond strength between heat curing denture base resin and reliners, to have more kinds of silane coupling agent and liner for studies of chemical bonding is considered it should be continued.

Comparison and evaluation of tensile bond strength of two soft liners to the denture base resin with different surface textures: An in vitro study

Introduction: Debonding of soft liners from the denture results in localized unhygienic conditions and often causes functional failure of the prosthesis. Aims: The purpose of this study is to evaluate and compare of the bond strength of the two permanent soft denture liners to a denture base resin with different surface preparations. Subjects and Methods: All the specimens were prepared by stainless steel dies which are duplicated and wax patterns were fabricated, which are then flasked and dewaxed. Heat cure denture base resin was mixed and trial packed into the mold. The specimens are recovered and divided into four sub-groups based on the surface to be prepared. The soft denture lining material, Super-soft (G.C. America Inc., USA) and Molloplast-B (Detax Gmbh and Co., KG, Germany) was packed and cured in between the two specimens. All the specimens were subjected to tension, until failure, in a Universal Testing Machine. Statistical Analysis Used: Analysis of variance using a Fischer's F test, unpaired t-test. Results: The tensile bond strengths of the four groups of both the soft liners were found to be very highly significant. The comparison between each group was made using a student's unpaired t-test for equality of means. It was found that when statistical analysis was made for Super-soft between group I and group II, group I and group IV the results were not significant whereas between group I and group III, group II and group III were strongly significant. The statistical analyses of the four groups of Molloplast-B soft liners were found to be very highly significant. Conclusions: Under the conditions of this in vitro study, conclusions were, sand papering the surface of the heat polymerized denture base resin increased the bond strength of the soft liner. Preparing holes on the surface of the denture base resin increases the bond strength because increase in the surface area and mechanical inter locking. Super-soft denture liner had the highest bond strength on all the surfaces than Molloplast-B.

화학적 표면처리에 따른 의치상 레진과 이장재 간의 전단 결합강도

본 논문은 monomer에서 결합증진에 많은 역할을 하는 MMA와 TEGDMA의 농도별 표면 처리와 silane coupling agent로 표면 처리한 것이 의치상 레진과 이장재간의 결합력에 미치는 영향에 대해 알아보고자 하였다. 의치상 레진에 MMA와 TEGDMA의 농도별 표면 처리와 silane coupling agent로 표면처리 후 이장재를 주입하여 전단결합강도를 측정하였다. MMA와 TEGDMA의 농도별 표면 처리에 따른 의치상 레진과 이장재간의 전단결합강도에서는 Vertex self curing resin에서 95%, 90%, 80%, Kooliner에서는 95%, 90%에서 유의적으로 높게 나타났다(P<0.05). 또한, silane coupling agent 5%로 표면 처리한 그룹이 Vertex self curing resin과 Kooliner 모두에서 전단결합강도가 유의적으로 높게 나타났다(P<0.05). 따라서 적절한 화학적 표면 처리는 의치상 레진과 이장재간의 결합력 증가에 영향을 미치리라 사료된다. 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.

Comparative evaluation of tensile bond strength of a polyvinyl acetate-based resilient liner following various denture base surface pre-treatment methods and immersion in artificial salivary medium: An in vitro study.

Background and Aim:This study was formulated to evaluate and estimate the influence of various denture base resin surface pre-treatments (chemical and mechanical and combinations) upon tensile bond strength between a poly vinyl acetate-based denture liner and a denture base resin.Materials and Methods:A universal testing machine was used for determining the bond strength of the liner to surface pre-treated acrylic resin blocks. The data was analyzed by one-way analysis of variance and the t-test (α =.05).Results:This study infers that denture base surface pre-treatment can improve the adhesive tensile bond strength between the liner and denture base specimens. The results of this study infer that chemical, mechanical, and mechano-chemical pre-treatments will have different effects on the bond strength of the acrylic soft resilient liner to the denture base.Conclusion:Among the various methods of pre-treatment of denture base resins, it was inferred that the mechano-chemical pre-treatment method with air-borne particle abrasion followed by monomer application exhibited superior bond strength than other methods with the resilient liner. Hence, this method could be effectively used to improve bond strength between liner and denture base and thus could minimize delamination of liner from the denture base during function.

Self-cleaning Ability of a Photocatalyst-containing Denture Base Material

This study examined the ability of a photocatalyst mixed in a denture base resin to decompose organic substances which adhered to the denture base resin surface. The photocatalyst was mixed with denture base resin at concentrations of 0, 5, 10, and 15% (w/w). Decomposition test, bending test, and surface roughness measurement were performed at 1, 7, 30, 90, and 180 days after polymerization. Decomposition ability was evaluated based on the residual amount of methylene blue (MB) dissolved in ethanol after UV irradiation for 12 hours. As the mixing ratio increased, the amount of MB in the solution decreased. Meanwhile, no changes in the amount of MB in the immersion solution were observed in the photocatalyst-free resin specimen. Therefore, the results indicated that a denture base resin containing a photocatalyst might have a photocatalytic ability.

The evaluation of microleakage and bond strength of a silicone-based resilient liner following denture base surface pretreatment

The failure of adhesion between a silicone-based resilient liner and a denture base is a significant clinical problem. The purpose of this study was to examine the effects of denture base resin surface pretreatments with different chemical etchants preceding the silicone-based resilient liner application on microleakage and bond strength. The initial effects of chemical etchants on the denture base resin in terms of microstructural changes and flexural strength were also examined. Forty-two polymethyl methacrylate (PMMA) denture base resin (Meliodent) specimens consisting of 2 plates measuring 30 x 30 x 2 mm were prepared and divided into 7 groups (n = 6). Specimen groups were treated by immersion in acetone for 30 (A30) or 45 (A45) seconds, methyl methacrylate monomer for 180 (M180) seconds, and methylene chloride for 5 (MC5), 15 (MC15) or 30 (MC30) seconds. Group C had no surface treatment and served as the control. Subsequently, an adhesive (Mollosil) and a silicone-based resilient denture liner (Mollosil) were applied to the treated surfaces, and all specimens were immersed in the radiotracer solution (thalium-201 chloride) for 24 hours. Tracer activity (x-ray counts), as a parameter of microleakage, was measured using a gamma camera. For bond-strength measurement, 84 rectangular PMMA specimens (10 x 10 x 40 mm) were surface-smoothed for bonding and treated with the different chemical etchants using the same previously described group configurations. The adhesive and the silicone-based denture liner were applied to the treated surfaces. Tensile bond-strength (MPa) was measured in a universal testing machine. Flexural strength measurement was performed with 49 PMMA specimens (65 x 10 x 3.3 mm according to ISO standard 1567) in 7 groups (n = 7), with 1 flat surface of each treated with 1 of the chemical etchants preceding adhesive application. The flexural strength (MPa) was measured using a 3-point bending test in a universal testing machine. The data were analyzed by 1-way analysis of variance and the Tukey HSD test (alpha = .05). Significant differences were found between the groups in terms of microleakage (P < .0001). The lowest microleakage was observed in group M180 (30,000 x-ray counts) and the highest in the control group (44,000 x-ray counts). The mean bond strength to PMMA resin ranged from 1.44 to 2.22 MPa. All treated specimens showed significantly higher bond strength than controls (P < .01). The flexural strength values all significantly differed (P < .05). All experimental specimens that had chemical surface treatments showed lower flexural strength than controls (P < .05). Treating the denture base resin surface with chemical etchants increased the bond strength of silicone-based resilient denture liner to denture base and decreased the microleakage between the 2 materials. Considering the results of both tests together, the use of methyl methacrylate monomer for 180 seconds was found to be the most effective chemical treatment.

Influence of Carbon Chain Length of Fluorinated Alkyl Acrylate on Mechanical Properties of Denture Base Resin

Hayashi et al. recently succeeded in preparing a filling polymer composed of methyl methacrylate and perfluorooctylethyl acrylate (C8F). They suggested that the addition of C8F-added polymer beads could inhibit bacterial adherence to the surface of denture base resin. The objective of this study was to examine the influence of carbon chain length of fluorinated alkyl acrylate on mechanical properties of test specimens ; perfluorobutylethyl acrylate (C4F), perfluorohexylethyl acrylate (C6F), C8F and perfluorodecylethyl acrylate (C10F) were used as fluorinated alkyl acrylates. The glass transition temperature of test specimens appeared to be greater as carbon chain length of fluorinated alkyl acrylate increased. Knoop hardness was lowest in C6F-added specimens (C6FA), while all test specimens gave lower values than the control. The direct tensile strengths of fluoromonomer-added specimens were lower than the control, while relatively lower strengths were seen in C6FA or C8F-added specimens (C8FA). Although Knoop hardness and direct tensile strength decreased after addition of fluorinated alkyl acrylates, these mechanical properties remained within the limits recommended by the Japanese Society for Dental Materials and Devices for denture base resin. This study suggests that the new denture base resin is clinically acceptable with regard to mechanical properties.

床用レジンと常温重合レジンの接着強さの改善に関する研究 第１報 床用レジンの水分含有状態が接着強さに及ぼす影響

Secondary failure in adhesion at the denture base resin and self-curing resin interface is a common problem with repaired or relined denture. It is caused by insufficient bond strength of both materials. Various organisms, bacteria, and plenty of water penetrating the denture base resin are considered to be the important factors which decrease the bond strength of both materials. The purpose of this investigation was to determine the effect of water absorbed in the denture base resin on shear bond strength and bond durability between the denture base resin and self-curing resins. In addition, effects of some chemical and mechanical etching treatments of the denture base resin surface on shear bond strength between two materials were also studied.The results were as follows:1. Bond strength and durability of water saturated denture base resin and self-curing resin were not necessarily decreased in comparison with the use of dried denture base resin.2. In case of using Unifast II, bond durability to the thoroughly dried denture base resin was markedly decreased.3. Unifast II demonstrated the highest bond strength and durability to the denture base resin treated with 50μm aluminum oxide sandblasting.4. Tokuso Rebase (Normal Set) demonstrated the highest bond durability to the denture base resin treated with methylene chloride.

義歯用歯磨剤による床用レンジの摩耗

Abrasion of denture base resin by dentifrice manufactured for dentures was compared with that by ordinary tooth paste.Denture base samples were prepared using microwave-polymerized base resin. Using a brushing abrasion tester, the samples were brushed one hundred thousand times to determine the amount of abrasion and the surface roughness. SEM observation was also carried out. In addition, the X-ray diffraction and thermal weight of the dentifrice were measured.Brushing with the dentifrice for dentures resulted in a larger amount of abrasion compared to the ordinary tooth paste. Thus denture base resin was found to be liable to be abraded by brushing with the dentifrice manufactured for dentures. SEM observation and measurement of the surface roughness demonstrated that the surface of denture base resin underwent large changes by brushing with the dentifrice manufactured for dentures.The results of this study by SEM observation, X-ray diffraction measurement, and thermal weight measurement suggested that the difference in abrasiveness was due to the differences in the kind and grain size of the polishing material contained in dental paste.

Composition and effect of denture base resin surface primers for reline acrylic resins

This study investigated the effect of resin surface primers for reline acrylic resins on the surface texture of denture base resin by use of scanning electron microscopy. Analysis of the composition of the primers was also conducted. The composition of the primers was classified into three groups: solvent based, monomer based, and monomer and polymer based. Scanning electron microscopic observation revealed various effects of the primers on the denture base resin surface, which depended on the composition of primers.

In vitro Adherence of Microorganisms to Denture Base Resin with Different Surface Texture

We examined the effects of various denture base resin surface textures on the adherence of microorganisms. S. sanguis and B. gingivalis adhered in greater amounts to the denture base resin than the other microorganisms tested. As to bacterial adherence according to polishing state, S. oralis, B. gingivalis C-101, and B. intermedius C-001 more adhered to the No. 400 paper-polished surface than to the buff-polished and smoothening-treated surfaces. S. sanguis less adhered to the smoothening-treated surface. S. mitis and C. albicans, on the other hand, more adhered to the smoothening-treated surface. For the other microorganisms tested, no relationship was observed between surface texture and bacterial adherence. The fall-off test revealed no remarkable differences in the fall-off of S. sanguis and B. gingivalis C-101 by the types of surface treatment. However, the fall-off of C. albicans was poorest from the No. 400 paper-polished surface. These results indicate that smoothening the denture base surface is important for denture plaque control.