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1.
J Appl Oral Sci ; 29: e20200448, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33787729

RESUMEN

OBJECTIVE: Denture adhesives need complete removal due to their frequent replacement. Our study investigates the removal of denture adhesives from denture base materials, using different methods. METHODOLOGY: PMMA and Polyamide denture base materials were used to fabricate 120 samples (15×15×1.5mm). One side of the samples was left as processed and the other polished with a usual procedure, hydrated for 24 h, dried, and weighted. They received 0.2 g of three adhesive creams on their unpolished surface (Corega, Olivafix, Fittydent), pressed on polysulfide material, stored under 37°C and 95% rel. humidity for 1 h and 60 of them, following their separation from polysulfide base, brushed under running water, whereas the rest inserted in a cleanser bath (Fittydent Super) for 5 min. The samples were dried and inserted in the oven (37°C) for additional 10 min and weighted again. Roughness tests of denture materials and light microscopy of adhesives creams were also used to evaluate the materials. Time lapse images of spayed with water adhesives on PMMA base were also taken to evaluate the volumetric changes of adhesives. Weight data before and after adhesive removal, indicating the amount of remaining adhesive, were statistically analyzed using Welch's ANOVA and Games-Howell multiple comparisons tests at α=0.05 level of significance. RESULTS: Roughness of Polyamide was higher than PMMA and Fittydent showed greater volumetric changes than the others. Significant differences (p<0.05), were found between PMMA and Polyamide bases, between Olivafix and Fittydent adhesives, and between brushing and cleansing methods but only for PMMA-Olivafix combination. CONCLUSIONS: Adhesives showed a stronger adherence to PMMA surface, and Fittydent was the most difficult to be removed. Removal methods were not effective for all adhesives or denture base materials. These indicate that removal methods, adhesive type and denture base material are all playing a significant role in the removal of adhesives from denture surfaces.


Asunto(s)
Bases para Dentadura , Nylons , Adhesivos , Ensayo de Materiales , Polimetil Metacrilato , Propiedades de Superficie
2.
J Prosthet Dent ; 125(4): 706.e1-706.e6, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33581867

RESUMEN

STATEMENT OF PROBLEM: The high recurrence rates of denture stomatitis may be associated with the resistance of biofilms to therapeutics. Therefore, methods that provide biomaterials with antifungal properties are an attractive solution to improving microbial control. PURPOSE: The purpose of this in vitro study was to modify conventional polymethyl methacrylate (PMMA) through the incorporation of metal methacrylate monomers and to evaluate the physicomechanical and optical properties and antifungal activity of the modified materials. MATERIAL AND METHODS: Experimental denture base acrylic resins were fabricated through the addition of zirconium methacrylate (ZM), tin methacrylate (TM), and di-n-butyldimethacrylate-tin (DNBMT) to the liquid of a commercially available denture base PMMA resin. Unmodified PMMA resin was used as the control. The degree of conversion of the materials was tested through Fourier transform infrared spectroscopy (n=3). A digital spectrophotometer was used to assess the color change of the modified materials (n=8). Differences in Knoop hardness and roughness between experimental groups were also evaluated (n=8). A biofilm accumulation test with Candida albicans (ATCC 62342) (n=4) was performed for 5 days in Sabouraud broth culture supplemented with 10% sucrose. Data were subjected to analysis of variance and the post hoc Tukey honestly significant difference test (α=.05). RESULTS: The degree of conversion and color-change values of the experimental materials were statistically similar to those of the control (P=.593). The incorporation of DNBMT significantly increased the hardness of the modified material (P=.014). The ZM, TM, and DNBMT groups had higher antifungal activity against C. albicans (P=.001) and lower roughness than the control group (control 0.65 ±0.05 µm; ZM 0.34 ±0.09 µm, TM 0.34 ±0.11 µm, and DNBMT 0.41 ±0.08 µm). CONCLUSIONS: The metal-containing methacrylate monomers provided antifungal action to the modified materials without affecting the physicomechanical or optical properties of the denture base resin. ZM, TM, and DNBMT are potential reactive agents for the fabrication of PMMA denture base resins with antifungal properties.


Asunto(s)
Bases para Dentadura , Polimetil Metacrilato , Resinas Acrílicas , Antifúngicos , Candida albicans , Ensayo de Materiales , Metacrilatos , Propiedades de Superficie
3.
Int J Prosthodont ; 34(1): 70-78, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570522

RESUMEN

PURPOSE: To evaluate the effect of a surface sealant agent on the color stability and surface roughness (Ra) of two denture base materials: polymethyl methacrylate (PMMA) and nylon. MATERIALS AND METHODS: A total of 96 disk-shaped specimens (10 × 2 mm) were fabricated from heat-cured PMMA and nylon denture base materials (n = 48/material). Each of the color stability and Ra tests were performed on half of the samples in each material group (n = 24), and these subgroups were then subdivided according to the surface treatment applied: 12 specimens were conventionally polished, serving as the control group, and 12 specimens received a sealant on the surface in addition to the surface polishing. Color stability was assessed through measuring the CIEL*a*b* color parameters before and after immersion in coffee solution. Ra was measured and scanning electron microscopy (SEM) photomicrographs were taken before and after thermocycling. Statistical analysis was done using 2-way analysis of variance (α = .05). RESULTS: The surface sealant agent significantly increased the color stability of both materials (P = .047). However, it had no significant effect on the Ra of materials before (P = .600) or after (P = .583) thermocycling. Nylon had a significantly rougher surface than PMMA both before and after thermocycling (P < .001). Similarly, SEM observations show a more irregular texture for nylon than for PMMA. CONCLUSION: Although the sealant agent had no significant effect on the Ra before or after thermocycling, it significantly decreased the color change of nylon and PMMA disks. Based on both statistical analyses and SEM observations, the Ra of PMMA was lower than nylon denture base material.


Asunto(s)
Nylons , Polimetil Metacrilato , Color , Bases para Dentadura , Ensayo de Materiales , Propiedades de Superficie
4.
J Prosthodont ; 30(3): 257-263, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33415779

RESUMEN

PURPOSE: An in vitro study to compare the adaptation of denture bases fabricated with 4 different techniques using volumetric 3-dimentional (3D) analysis. MATERIAL AND METHODS: Edentulous maxillary and mandibular casts were scanned, and standardized denture bases were designed using CAD design software. The same standard tessellation language (STL) data were used to produce the denture bases with 4 different fabrication methods: compression molding (CM), injection molding (IM), PMMA milling (PM), and 3D printing (3D) (n = 11/group). Milled wax denture bases were used to fabricate CM and IM groups. Denture bases placed on edentulous casts were scanned using micro-computed tomography (micro-CT). Volumetric gap between denture base and cast was calculated from 6 locations for maxilla (anterior ridge crest, posterior ridge crest, labial vestibule, buccal vestibule, palate, and posterior palatal seal) and 3 locations for mandible (intermolar, molar, and retromolar) in addition to overall gap measurements for edentulous arches. The data were analyzed with factorial analysis of variance (ANOVA), 1-way ANOVA, and post-hoc Duncan tests. Reproducibility of fabrication methods with regard to each location was assessed using Z test (α = 0.05). RESULTS: In the maxilla, the highest and lowest palatal gap measurements were recorded for CM (898.44 ± 87.73 mm3 ) and PM (357.16 ± 57.68 mm3 ) (p = 0.05). The highest gap measurements for CM and 3D were at palate and, for IM and PM were at posterior ridge crest. In mandible, the volumetric gap measurements for CM were the highest and for PM were the lowest irrespective of location (p = 0.05). PM group showed the best reproducibility and adaptation with the lowest overall mean gaps for both edentulous arches (p = 0.05). CONCLUSIONS: Denture bases milled from PMMA blocks showed better adaptation than 3D printed, or wax milled and conventionally fabricated denture bases for both maxillary and mandibular arches. PMMA milling is a reproducible technique that enables the construction of accurate dentures. Clinicians should be cautious about the palatal gap when the compression molding technique is used. Micro-CT is a valid technique for evaluating the denture base adaptation.


Asunto(s)
Bases para Dentadura , Diseño de Dentadura , Diseño Asistido por Computadora , Dentadura Completa , Reproducibilidad de los Resultados , Microtomografía por Rayos X
5.
Molecules ; 25(24)2020 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-33322112

RESUMEN

Chitosan (CS) and its derivatives show antimicrobial properties. This is of interest in preventing and treating denture stomatitis, which can be caused by fungi. Therefore, the aim of this study was the development of a novel antifungal denture base material by modifying polymethyl methacrylate (PMMA) with CS-salt and characterizing its antifungal and surface properties in vitro. For this purpose, the antifungal effect of chitosan-hydrochloride (CS-HCl) or chitosan-glutamate (CS-G) as solutions in different concentrations was determined. To obtain modified PMMA resin specimens, the CS-salts were added to the PMMA before polymerization. The roughness of these specimens was measured by contact profilometry. For the evaluation of the antifungal properties of the CS-salt modified resins, a C. albicans biofilm assay on the specimens was performed. As solutions, both the CS-G and CS-HCl-salt had an antifungal effect and inhibited C. albicans growth in a dose-dependent manner. In contrast, CS-salt modified PMMA resins showed no significant reduced C. albicans biofilm formation. Furthermore, the addition of CS-salts to PMMA significantly increased the surface roughness of the specimens. This study shows that despite the antifungal effect of CS-salts in solution, a modification of PMMA resin with these CS-salts does not improve the antifungal properties of PMMA denture base material.


Asunto(s)
Antifúngicos/química , Antifúngicos/farmacología , Quitosano/química , Bases para Dentadura , Polimetil Metacrilato/química , Sales (Química)/química , Candida albicans/efectos de los fármacos , Ensayo de Materiales , Pruebas de Sensibilidad Microbiana , Propiedades de Superficie
6.
Oral Health Prev Dent ; 18(1): 999-1010, 2020 11 20.
Artículo en Inglés | MEDLINE | ID: mdl-33215491

RESUMEN

PURPOSE: This study investigated the effect of long-term daily chemical disinfection on the topographic and Candida albicans biofilm formation on a denture base resin and a reline acrylic resin. MATERIAL AND METHODS: Circular samples (14 × 1.2 mm) were fabricated from a denture base (Vipi Wave) and reline acrylic resins (Tokuyama Rebase Fast II). Samples were kept in 50 ml of distilled water (48 h at 37°C). Subsequently, the samples were immersed in five different solutions: 0.5% sodium hypochlorite; 3.8% sodium perborate; 2% chlorhexidine gluconate; apple vinegar containing 4% maleic acid; and distilled water (control group). The specimen was immersed in the solutions for 8 h daily and transferred to distilled water at 37°C for more 16 h. The surface topographic and Candida albicans (ATCC 90028) biofilm formation were evaluated at baseline (before chemical disinfection) and after 1, 3 and 6 months of immersion. The surface topographic was evaluated by arithmetical roughness average (Ra) and scanning electron microscope (SEM), while the biofilm formation was evaluated by colony-forming units (CFU/ml) method and Alamar Blue assay (cell metabolism). The results were evaluated by three-way analysis of variance (ANOVAs) and post-hoc tests (α = 0.05). RESULTS: The results showed statistically significant effects from the type of acrylic resin (p = 0.029) and time (p <0.001) on the roughness of the specimen. In general, the reline resin had higher roughness than the denture base resin. In addition, the roughness of the samples after 1, 3 and 6 months of immersion in the cleaning solutions was higher than at baseline. In relation to the microbiological assays, there were no statistically significant differences (p >0.055) in the CFU/ml values of the biofilms among the different resins, periods of time and cleaning solutions. Considering the metabolism of the cells within the biofilms, the results showed that, at baseline, it was statistically significantly higher (p <0.05) than after 1, 3 and 6 months of storage. The SEM images showed that all disinfectant solutions provided surface changes of both acrylic resins (base and reline) after 1, 3 and 6 months of immersion. CONCLUSIONS: The roughness of both acrylic resins was affected by the disinfection in all cleaning agents, increasing over time, and this effect was more evident in the reline acrylic resin group. This surface change was also observed in the SEM images. While the number of cells within the biofilms was not affected by immersion in the cleaning agents, their metabolism was lower after 1, 3 and 6 months of immersion.


Asunto(s)
Candida albicans , Desinfección , Resinas Acrílicas , Biopelículas , Bases para Dentadura , Limpiadores de Dentadura/farmacología , Ensayo de Materiales , Propiedades de Superficie
7.
Braz Dent J ; 31(5): 523-531, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33146337

RESUMEN

Thiourethane additives have been shown to improve properties in several dental polymer applications. The aim of this study was to verify the effect of the addition of thiourethane oligomers and acrylamide or isobornyl-based plasticizers on the physical properties of the denture base acrylic resin polymerized with microwaves. Thiourethane oligomer (TU) was synthetized and added to microwaved acrylic resin in proportions varying between 3 and 14 wt%. Separate experimental groups included the addition of dimethyl acrylamide (DMAM) and isobornyl methacrylate as plasticizers, at concentrations varying from 5 to 20 wt%. Samples were polymerized using microwave energy at 500 Watts for 3 min, deflasked at room temperature, stored in water at 37 °C for 24 h, and evaluated for: linear dimensional change, gloss, Knoop hardness, surface roughness, impact strength, yield strength, elastic modulus, toughness, yield strength, viscosity, glass transition temperature and network heterogeneity, and water sorption/solubility. Data were analyzed with ANOVA/Tukey's post-hoc test (a=5%). The addition of TU led to properties that were similar or worse than the materials to which it was not added, except for dimensional stability. The impact on properties was statistically significant for all materials above 20% addition of TU. The addition of DMAM at 5 wt% or isobornyl methacrylate at 10 wt% improved yield strength and modulus, but increased water sorption and solubility. Except for dimensional stability, the addition of thiourethane oligomers to acrylic denture base materials compromised most tested properties. The use of DMAM and isobornyl methacrylate improved properties for selected compositions.


Asunto(s)
Bases para Dentadura , Microondas , Materiales Dentales , Ensayo de Materiales , Polimerizacion , Polimetil Metacrilato , Propiedades de Superficie
8.
J Oral Sci ; 62(4): 420-422, 2020 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-32908079

RESUMEN

This study compared the mechanical properties and molecular distribution of a polymethyl methacrylate (PMMA) block (Dry) with specimens that were fabricated by a conventional method and cured in a wet environment (Control). Two specimen types were fabricated with heat-curing denture base resin. Dry specimens were polymerized at high pressure and in a dry system, while Control specimens were polymerized with a heat-curing method, in accordance with the manufacturer's recommended procedures. Specimens from each group were evaluated for three-point bending, water sorption and solubility, and color change, and by gel permeation chromatography (GPC). Mean values for the flexural strengths and moduli of the Dry specimens were significantly higher than those of the Control specimens (P > 0.05). Water sorption and discoloration values of the Dry group were significantly lower than those of the Control group. Mean weight-average molecular weights of the Dry group were higher than those of the Control group. As compared with the conventional method, the present method of fabricating PMMA blocks under high pressure yields superior mechanical properties for the denture base.


Asunto(s)
Diseño Asistido por Computadora , Polimetil Metacrilato , Bases para Dentadura , Dentaduras , Ensayo de Materiales , Estrés Mecánico , Propiedades de Superficie
9.
Niger J Clin Pract ; 23(9): 1266-1273, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32913167

RESUMEN

Aims: This study evaluated the effect of oxygen plasma and argon plasma treatments with different application times on tensile bonding of a silicone-based denture liner to polymethylmetacrylate (PMMA). Methods: Seven groups (n = 5) were prepared and six of them treated by argon plasma or oxygen plasma with 30s, 60s, and 120s, respectively; one group was left untreated served as control. After processing of denture liner, the specimens were deflasked and stored dry for 24 h, and they were then subjected to tensile bond strength testing. Differences in tensile bond strength values were determined using one-way ANOVA (α = 0.05). Results: Highest tensile bond strengths were observed in the oxygen plasma groups, followed by untreated group and argon plasma groups in turn in order. Tensile bond strenght were increased with time for both type of plasma applications tested. Conclusion: This study suggests that the adhesion between PMMA and denture liner is improved under conditions of oxygen plasma treatment with extended exposure time rather than argon plasma treatment.


Asunto(s)
Coagulación con Plasma de Argón , Recubrimiento Dental Adhesivo/métodos , Alineadores Dentales , Polimetil Metacrilato/química , Siliconas/química , Resistencia a la Tracción , Argón , Bases para Dentadura , Humanos , Ensayo de Materiales , Oxígeno , Propiedades de Superficie
10.
Braz Oral Res ; 34: e110, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32876123

RESUMEN

Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.


Asunto(s)
Candida albicans , Resinas Acrílicas , Bases para Dentadura , Dióxido de Silicio , Propiedades de Superficie
11.
Wiad Lek ; 73(6): 1097-1102, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32723933

RESUMEN

OBJECTIVE: The aim of the research is to study the physical and mechanical parameters of the bases in removable laminar dentures after modification of their surface. PATIENTS AND METHODS: Materials and methods: the studied samples were divided into two groups (group I - acrylic plastics, and group II - acrylic plastics with fullerene С60 nanocoating), 50 samples in each group. The coefficients of water absorption, water solubility, microhardness and deformation characteristics of materials were studied. RESULTS: Results and conclusions: The material covered with fullerene С60 has a lower coefficient of water absorption and water solubility, which amounted to 0.55% and 0.23% respectively, from the initial weight of samples, as compared with acrylic plastics without coating (0.71% and 034%, respectively). The strength parameters of samples of group ІІ were higher by 13.5% as compared to group І. The given results of water absorption and water-solubility show that acrylic plastics with fullerene С60 molecules coating has a lower coefficient of water absorption and water solubility, in comparison with acrylic plastics without coating. This indicates a higher degree of resistance to biodegradation of the modified surface material, in turn reducing the washing-out of residual monomer from the denture, which directly improves the strength parameters of the acrylic plastics and can prevent the development of denture stomatitis.


Asunto(s)
Bases para Dentadura , Fulerenos , Resinas Acrílicas , Ensayo de Materiales , Plásticos , Agua
12.
BMC Oral Health ; 20(1): 193, 2020 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-32641017

RESUMEN

OBJECTIVE: To compare the antifungal action of two commercially available denture cleaning agents to that of standard clinical solutions, and determine their effects on the polymethyl methacrylate (PMMA) acrylic resin denture surface. METHODS: Candida albicans growth was analyzed by colony forming assay, and the methyl thiazolyl tetrazolium (MTT) assay was used to evaluate biofilm formation and cell adhesion. The morphology and roughness of PMMA acrylic resin surface was measured by scanning electron microscopy (SEM) images and stylus method. RESULTS: Clene®, Polident® and 3% NaHCO3 solutions showed significantly greater antifungal effects in terms of both inhibiting growth and biofilm formation. In addition, Clene® solution prevented adhesion of C. albicans on cell culture plates compared to filter-sterile tap water, whereas other reagents did not have an inhibitory effect. One-month immersion in the different cleaning reagents significantly inhibited fungal adhesion on the PMMA surface Clene®, Polident® and 3% NaHCO3 showed greater effect compared to PBS and filter-sterile tap water. Finally, none of the cleansing agents significantly affected the morphology and roughness of the PMMA surface. CONCLUSION: Clene®, Polident® and 3% NaHCO3 solutions can inhibit C. albicans growth and biofilm formation to some extent on cell culture plates, and significantly inhibit fungal adhesion on the PMMA surface without affecting surface morphology and roughness.


Asunto(s)
Biopelículas/efectos de los fármacos , Candida albicans/efectos de los fármacos , Materiales Dentales/química , Bases para Dentadura , Limpiadores de Dentadura/farmacología , Polimetil Metacrilato/química , Polimetil Metacrilato/farmacología , Biopelículas/crecimiento & desarrollo , Candida albicans/crecimiento & desarrollo , Humanos , Peróxidos , Propiedades de Superficie
13.
J Contemp Dent Pract ; 21(4): 353-358, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32584268

RESUMEN

AIM: This study was conducted to evaluate the grape seed extract (GSE)-modified soft liner regarding surface roughness, tensile bond strength to the denture base material, and the antifungal activity. MATERIALS AND METHODS: The GSE powder was blended with the soft liner powder in ratios of 5 and 10% w/w, and three groups were employed: I, control; II, 5% w/w GSE-modified soft liner; III, 10% w/w GSE-modified soft liner. Evaluation parameters included surface roughness, tensile bond strength to the denture base material, and the antifungal activity. Changes in surface topography were evaluated by scanning electron microscopy. The statistical analysis was performed using the one-way ANOVA followed by the Tukey's test (α = 0.05). RESULTS: The 5% w/w GSE-modified soft liner showed a significant increase in surface roughness, while both ratios (5 and 10% w/w) of the modified-soft liner exhibited significant increase in tensile bond strength and antifungal activity (p < 0.05). CONCLUSION: The GSE of 10% w/w considerably enhanced the antifungal activity and tensile bond strength of the modified soft liner to the denture base material without compromising its surface roughness. CLINICAL SIGNIFICANCE: The 10% w/w GSE-modified soft liner may be a promising formulation with antifungal activity. It could inhibit fungal adherence and development of fungi-induced lesions or exacerbation of existing ones.


Asunto(s)
Recubrimiento Dental Adhesivo , Alineadores Dentales , Extracto de Semillas de Uva , Antifúngicos , Bases para Dentadura , Ensayo de Materiales , Propiedades de Superficie , Resistencia a la Tracción
14.
J Contemp Dent Pract ; 21(4): 367-371, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32584270

RESUMEN

AIM: The aim of this study was to compare the adaptation of complete denture base (CDB) manufactured by three different techniques: conventional, milling, and three-dimensional (3-D) printing. MATERIALS AND METHODS: A master cast was duplicated to create 60 gypsum casts. Twenty casts (n = 20) were attributed to each group. In the computer-aided design and computer-aided manufacturing (CAD/CAM) groups (milling and 3-D printing), the 40 gypsum casts reserved for these two groups were scanned. An STL file was obtained and a master CDB was designed and then fabricated according to each technique. In the conventional group, a polyvinyl siloxane putty mold was obtained from the milled CDB, and this mold was used to fabricate 20 conventional denture bases by compression molding using the silicon-gypsum technique in a bronze flask. The inner surfaces of the obtained 60 CDB were scanned and superimposed over their corresponding master cast. Deviation analyses were calculated using digital subtraction technique. Five functional areas (posterior palatal seal, anterior border seal, crest of the ridge, maxillary tuberosities, and palate) were selected to evaluate the variations in CBD adaptation. RESULTS: Based on the results and color maps of all selected regions, milling technique offers the best adaptation. The crest of ridge in the conventional technique showed the least adaptation and the posterior palatal seal in the 3-D printing technique showed the best adaptation. CONCLUSION: Within the limitations of this study, the CAD/CAM fabrication techniques seem to offer better adaptation of CDB compared to the conventional fabrication technique. Milled CDBs presented the most homogeneous distribution of adaptation, yet the 3-D printing process seems a promising techniques that needs to be addressed and perfected. CLINICAL SIGNIFICANCE: The CAD/CAM technologies can help overcome many limitations related to conventional impressions and therefore should be well investigated to improve the edentulous patient's quality of life.


Asunto(s)
Bases para Dentadura , Diseño de Dentadura , Diseño Asistido por Computadora , Dentadura Completa , Humanos , Impresión Tridimensional , Calidad de Vida
15.
Braz Oral Res ; 34: e050, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32578760

RESUMEN

Candida infection is an important cause of morbidity and mortality in immunocompromised patients. The increase in its incidence has been associated with resistance to antimicrobial therapy and biofilm formation. The aim of this study was to evaluate the efficacy of tea tree oil (TTO) and its main component - terpinen-4-ol - against resistant Candida albicans strains (genotypes A and B) identified by molecular typing and against C. albicans ATCC 90028 and SC 5314 reference strains in planktonic and biofilm cultures. The minimum inhibitory concentration, minimum fungicidal concentration, and rate of biofilm development were used to evaluate antifungal activity. Results were obtained from analysis of the biofilm using the cell proliferation assay 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and confocal laser scanning microscopy (CLSM). Terpinen-4-ol and TTO inhibited C. albicans growth. CLSM confirmed that 17.92 mg/mL of TTO and 8.86 mg/mL of terpinen-4-ol applied for 60 s (rinse simulation) interfered with biofilm formation. Hence, this in vitro study revealed that natural substances such as TTO and terpinen-4-ol present promising results for the treatment of oral candidiasis.


Asunto(s)
Biopelículas/efectos de los fármacos , Candida albicans/efectos de los fármacos , Aceite de Árbol de Té/farmacología , Terpenos/farmacología , Resinas Acrílicas , Análisis de Varianza , Antifúngicos/farmacología , Biopelículas/crecimiento & desarrollo , Candida albicans/crecimiento & desarrollo , Bases para Dentadura/microbiología , Pruebas de Sensibilidad Microbiana , Microscopía Confocal , Valores de Referencia , Reproducibilidad de los Resultados , Estadísticas no Paramétricas , Aceite de Árbol de Té/química , Terpenos/química
16.
J Prosthet Dent ; 124(5): 615.e1-615.e7, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32540125

RESUMEN

STATEMENT OF PROBLEM: Incorporating chlorhexidine into soft lining materials has been suggested to reduce biofilm development on the material surface and treat denture stomatitis. However, evaluation of the physicochemical properties of this material is necessary. PURPOSE: The purpose of this in vitro study was to evaluate the physicochemical properties of resin-based denture soft lining materials modified with chlorhexidine diacetate (CDA). MATERIAL AND METHODS: Two soft lining resins were tested, one based on polymethyl methacrylate (PMMA) and the other on polyethyl methacrylate (PEMA), into which 0.5%, 1.0%, or 2.0% of CDA was incorporated; the control group had no CDA. The specimens were stored for 2 hours, 48 hours, 7, 14, 21, and 28 days and then analyzed for polymer crystallinity, Shore A hardness, degree of monomer conversion, residual monomer leaching, and CDA release. Data were analyzed by using a 3-way ANOVA and the Tukey HSD test (α=.05). RESULTS: The polymer crystallinity of PEMA and PMMA did not change after CDA incorporation. Shore A hardness increased over time, but not for any CDA concentrations tested after 28 days (P>.05). Considering the degree of conversion, PMMA-based resin showed no statistically significant difference (P>.05). However, PEMA-based resin showed a significant decrease (P<.05), which was reflected in a significant increase in residual monomer leaching from PEMA-based resin with the incorporation of 0.5% and 1.0% CDA (P<.05), mainly in the first 48 hours. PMMA-based resin showed no change in monomer leaching (P>.05). For both resins, the CDA release kinetics were related to monomer leaching; for PEMA-based resin, the values were significantly higher in the first 48 hours (P<.05), and for PMMA-based resin, the values were more sustained up to the last day of analysis. CONCLUSIONS: The incorporation of CDA did not affect the physicochemical properties of soft resins. The properties of PMMA were better than those of PEMA.


Asunto(s)
Clorhexidina , Polimetil Metacrilato , Bases para Dentadura , Dureza , Ensayo de Materiales , Metacrilatos , Propiedades de Superficie
17.
J Contemp Dent Pract ; 21(2): 166-170, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32381822

RESUMEN

AIM: The present in vitro study aimed to evaluate the transverse strength of heat cure acrylic denture base resins repaired with three different joint surface designs, repair material being the glass-fiber-reinforced self-cure repair material along with surface pretreatment. MATERIALS AND METHODS: A total of 40 heat cure resin specimens were fabricated and finished to a size of 64 mm × 10 mm × 2.5 mm. These specimens were divided into four groups of 10 each, with butt, round, and bevel repair surface joints, respectively, along with the control group. After the specimens were cut in the middle for the repair procedure to proceed, the aforementioned joint surface contours were prepared for groups I, II, and III, respectively, treated with dimethyl chloride for 30 seconds, and the repair was done with E-glass-fiber-reinforced self-cure repair material. RESULTS: The mean transverse strength of the control group was 100.37 N, which was highest (significant p value of <0.05), followed by group III (bevel joint) 54.23 N, group I (butt joint) 53.93 N, and group II (round joint) 44.55 N. CONCLUSION: Distribution of stresses evenly in the repair region will be achieved by the proper selection of the joint surface contour, and this study showed that the 45° bevel joint was an appropriate selection along with promising repair material and surface pretreatment. CLINICAL SIGNIFICANCE: Clinically, in the event of repairing a broken denture, a rapid and economically convenient material with superior physical and mechanical properties is important to maintain the adequate transverse strength of the repaired denture. Glass-fiber-reinforced autopolymerizing resin, with a 45° bevel joint design of the broken surfaces and surface pretreatment proved to reduce stress concentration, improving the transverse strength of the repaired heat cure denture base resins.


Asunto(s)
Bases para Dentadura , Calor , Reparación de la Dentadura , Ensayo de Materiales
18.
J Contemp Dent Pract ; 21(3): 285-290, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32434976

RESUMEN

AIM: The purpose of this in vitro research is to chemically characterize polymethyl methacrylate (PMMA) processed with 10% and 20% (v/v) tricyclodecane dimethanol diacrylate (TCDDMDA) comonomer. It also aimed to assess the degree of conversion (DC) and glass transition temperature (Tg) of the formed copolymers. MATERIALS AND METHODS: The experimental groups were processed with the TCDDMDA comonomer (10% and 20% v/v), whereas the control group was processed only with the methyl methacrylate monomer. The copolymerization was studied by nuclear magnetic resonance (NMR) spectroscopy. The surface characteristics and composition (wt%) were studied by field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy (cuboidal specimen; 5 mm × 5 mm × 3 mm), respectively. The DC and Tg of the formed copolymers (powdered form) were analyzed by Fourier transform infrared spectroscopy and differential scanning calorimetry, respectively. One-way analysis of variance with post hoc Bonferroni test was used to compare the mean values of DC% and Tg among the groups. RESULTS: The newly formed copolymer [P(MMA-co-TCDDMDA)] was chemically characterized by NMR and FESEM-EDX. The DC and Tg of the experimental groups were higher than the control. Tricyclodecane dimethanol diacrylate at 20% (v/v) concentration showed the highest DC and Tg. CONCLUSION: The addition of TCDDMDA comonomer improved the DC and Tg of the formed copolymer. CLINICAL SIGNIFICANCE: The P(MMA-co-TCDDMDA) copolymer is expected to improve the mechanical properties and biocompatibility of the denture base acrylic resin. This would result in improved denture quality and durability, thereby, imparting a better quality of life to the geriatric population.


Asunto(s)
Calor , Polimetil Metacrilato , Anciano , Bases para Dentadura , Humanos , Ensayo de Materiales , Calidad de Vida
19.
Indian J Dent Res ; 31(2): 282-290, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32436910

RESUMEN

Objective: This study evaluated the effect of chemical disinfection and microwave irradiation on the surface hardness and roughness of two commercially available hard relining materials (Ufi Gel hard, GC Kooliner) and one denture base resin (Trevalon). Materials and Methods: A total of 72 specimens (n = 24) were divided into four groups. C: Not disinfected, Cl: disinfected with 4% chlorhexidine solution, Gl: disinfected with 2% glutaraldehyde solution, Mw: disinfected with microwave irradiation (650 W; 6 min). Hardness and roughness measurements were made after polymerisation, 1st day, 14th day and 28th day. Results: Ufi Gel hard showed an increased roughness after 1st day (P = 0.021) following chemical disinfection and GC Kooliner showed similar results after 14th day (P < 0.05). Microwave irradiation showed a significant increase in surface roughness value after 1st day (P < 0.05) for both Ufi Gel hard and GC Kooliner. Hardness of both Ufi Gel (12.131 to 7.333 VHN) and Kooliner (9.133 to 5.276 VHN) was significantly reduced by chemical disinfection, while microwave irradiation resulted in an increased surface hardness of Kooliner (from 9.126 to 12.713 VHN) and Ufi Gel hard (from 11.698 to 14.940VHN). Results for Trevalon were not significant for both the disinfection methods. Conclusions: Microwave irradiation increased the surface roughness and hardness of Ufi Gel hard and Kooliner, while chemical disinfection resulted in a decreased hardness and increased roughness of both hard relining materials. There was no effect of either of the disinfection methods on Trevalon.


Asunto(s)
Bases para Dentadura , Alineadores Dentales , Desinfección , Dureza , Ensayo de Materiales , Microondas , Propiedades de Superficie
20.
Dent Med Probl ; 57(1): 95-102, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32307934

RESUMEN

Denture stomatitis (DS) is a multifactorial disease, but the proliferation of Candida albicans (C. albicans) is the main causative factor. Different modalities have been suggested for the prevention and treatment of DS. Among the different approaches that have been implemented to inhibit and control DS there are the topical application of antifungal agents, the surface modification of the denture base and the incorporation of antimicrobial agents into the denture base material. Antifungal agents can effectively control DS, but the recurrence of the disease is common. Accordingly, it has been suggested that coating the surface of the acrylic denture base may result in a decreased fungal adhesion. In recent years, nanotechnology has dominated the research, and several nanoparticles have demonstrated antifungal effects. Therefore, the aim of this article was to review the antifungal effects of the different methods that have been suggested for the prevention and/or control of DS as well as the antimicrobial activity of denture base acrylic resin additives, including nanoparticles. Studies reporting the incorporation of antifungal/antimicrobial agents into the polymethyl methacrylate (PMMA) denture base were included in this review. The PubMed, Web of Science, Google Scholar, and Scopus databases were searched for the articles published between January 2000 and December 2018 using the following key words: dental prosthesis, denture stomatitis, candidiasis, antifungal agents, biofilm formation, polymethyl methacrylate, and PMMA. The antimicrobial material incorporated into the resin may have a superior effect in preventing DS over simply coating the surface of the denture base. However, some antimicrobial fillers can have adverse effects on the physical and mechanical properties of the denture base resin.


Asunto(s)
Candida albicans , Estomatitis Subprotética , Resinas Acrílicas , Antifúngicos/uso terapéutico , Bases para Dentadura , Humanos , Estomatitis Subprotética/tratamiento farmacológico , Estomatitis Subprotética/prevención & control
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