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J. appl. oral sci ; 29: e20200448, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154618


Abstract Denture adhesives need complete removal due to their frequent replacement. Objective 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.

Denture Bases , Nylons , Surface Properties , Materials Testing , Adhesives , Polymethyl Methacrylate
J. appl. oral sci ; 29: e20200948, 2021. tab, graf
Article in English | LILACS | ID: biblio-1340105


Abstract Appropriated denture hygiene is a predictive factor for longevity of rehabilitation treatment and maintenance of the oral mucosal health. Although, disinfectant solutions are commonly used as denture cleansers, the impact of these solutions on acrylic resin-based dentures remain unclear. Objective To evaluate, in vitro, the antibiofilm activity of complete denture hygiene solutions and their effects on physical and mechanical properties of acrylic resin. Methodology For antibiofilm activity measurement acrylic resin specimens were contaminated with Candida albicans, Candida glabrata and Streptococcus mutans. After biofilm growth, the specimens were assigned to the hygiene solutions: Distilled water (Control); 0.2% Sodium hypochlorite (SH); Efferdent Power Clean Crystals (EPC) and 6.25% Ricinus communis (RC). The viability of microorganisms was evaluated by agar plate counts. In parallel, physical, and mechanical properties of the acrylic resin were evaluated after simulating a 5-year period of daily immersion in the previously mentioned solutions. The changes in surface roughness, color, microhardness, flexural strength, impact strength, sorption and solubility were evaluated. Data were compared by ANOVA followed by the Tukey test or Kruskal-Wallis followed by the Dunn test depending on the distribution (α=0.05). Results Regarding antibiofilm action, SH eliminated all microorganisms while EPC and RC exhibited moderate action against S. mutans (p=0.001) and C. glabrata (p<0.001), respectively. Relative to effects on the physical and mechanical properties of the acrylic resin, RC led to higher values of color change (p=0.030), hardness (p<0.001), surface roughness (p=0.006) and flexural strength (p<0.001). Moreover, RC induced the highest values of changes in solubility (p<0.001). EPC promoted greater changes in surface morphology, whereas immersion in SH retained the initial appearance of the acrylic resin surface. All hygiene solutions reduced the impact strength (p<0.05). Conclusion SH presented the most effective antibiofilm activity. In addition, changes on properties were observed after immersion in RC, which were considered within acceptable limits.

Acrylic Resins , Denture Cleansers/pharmacology , Surface Properties , Materials Testing , Hygiene , Biofilms , Denture Bases , Denture, Complete
J. appl. oral sci ; 29: e20200865, 2021. graf
Article in English | LILACS | ID: biblio-1286916


Abstract Denture stomatitis is the most frequent oral lesion in removable prosthesis wearers, with high recurrence rates and a complex treatment. Objective This study describes a protocol to obtain and to contaminate a palatal device with Candida albicans biofilm that could be used for an animal model of denture stomatitis. Methodology Acrylic resin devices (N=41) were obtained from impressions of the palates of Wistar rats with individual trays and polyether. The efficacy of microwave irradiation (MW), ultraviolet light (UV), or ultrasonic bath (US) was assessed by colony viability and spectrophotometric analyses (n=5) in order to select the most appropriate method for sterilizing the devices. Then, different devices (n=5) were contaminated with C. albicans and evaluated by CFU/mL determination, scanning electron microscopy, and laser confocal microscopy. Device stabilization was assessed with either autopolymerizing acrylic resins or a self-adhesive resin cement (n=2). The spectrophotometric data were analyzed by one-way ANOVA followed by the Tukey's HSD post-hoc test (α=0.05). Results MW was the only method capable of sterilizing the devices, and the contamination protocol developed a mature and viable C. albicans biofilm (~1.2 x 106 CFU/mL). The self-adhesive resin cement was the best stabilization material. Conclusions This acrylic resin palatal device was designed to be similar to the clinical situation of contaminated prostheses, with easy manufacturing and handling, effective stabilization, and satisfactory contamination. Thus, the acrylic device can be a valuable tool in the development of denture stomatitis in rats.

Animals , Rats , Stomatitis, Denture , Candida albicans , Palate , Acrylic Resins , Rats, Wistar , Biofilms , Denture Bases
Dental press j. orthod. (Impr.) ; 25(6): 43-48, Nov.-Dec. 2020. tab, graf
Article in English | LILACS, BBO | ID: biblio-1154053


ABSTRACT Objective: To evaluate different concentrations of Galla chinensis extract (GCE) added to poly(methyl methacrylate) (PMMA), which is widely used for fabrication of removable orthodontic appliances, regarding the effectiveness of this herbal extract on antimicrobial effect and flexural strength of PMMA. Methods: Acrylic resin samples containing 0.4%, 0.8% and 1.6% GCE were prepared. Flexural strength was investigated via three-point flexural strength test for the 15 acrylic resin blocks of each concentration. Disk diffusion test was used to evaluate antibacterial effects of incorporating the same concentrations of GCE into acrylic resin. All these three groups were compared with the control group, with no added GCE, regarding flexural strength and antibacterial properties. Results: Comparison of flexural strength between the three study groups and the control group showed significant differences between the groups (P=0.018). However, there was no significant difference between the groups containing GCE. There were significant differences in antimicrobial activity between the four groups (P=0.026). Conclusion: Within the limitations of this study, it is suggested that incorporation of GCE into PMMA would be beneficial for antimicrobial activity and flexural strength of PMMA, but further studies on other physical properties and antimicrobial effects on other bacterial strain would be beneficial prior to clinical investigations.

RESUMO Objetivo: Avaliar se diferentes concentrações de extrato de Galla chinensis (EGC) adicionado ao polimetilmetacrilato (PMMA), que é amplamente utilizado para a fabricação de aparelhos ortodônticos removíveis, interferem no efeito antimicrobiano desse extrato e na resistência à flexão do PMMA. Métodos: Foram preparadas amostras de resina acrílica com concentrações de 0,4%, 0,8% e 1,6% de EGC. Para a avaliação da resistência à flexão, utilizou-se o teste de flexão em três pontos para as 15 amostras de resina em cada concentração. O teste de disco-difusão foi utilizado para avaliar os efeitos antibacterianos da incorporação das mesmas concentrações de EGC na resina acrílica. Esses três grupos foram comparados ao grupo controle, sem adição do EGC, em relação à resistência à flexão e quanto às propriedades antimicrobianas. Resultados: As comparações dos três grupos com o grupo controle mostraram diferenças significativas (p=0,018) para a resistência à flexão. Entretanto, não houve diferença significativa entre os grupos contendo EGC. Foram encontradas diferenças significativas na atividade antimicrobiana entre os quatro grupos (p=0,026). Conclusão: Dentro das limitações desse estudo, parece que a incorporação de EGC no PMMA seria benéfica para a atividade antimicrobiana e a resistência à flexão do PMMA. Porém, estudos adicionais sobre outras propriedades físicas e sobre os efeitos antimicrobianos contra diferentes cepas de bactérias seriam interessantes antes de se fazer pesquisas clínicas.

Acrylic Resins , Denture Bases , Flexural Strength , Anti-Infective Agents , Anti-Bacterial Agents/pharmacology , Materials Testing , Plant Extracts/pharmacology
Braz. dent. j ; 31(5): 523-531, Sept.-Oct. 2020. tab
Article in English | LILACS, BBO | ID: biblio-1132329


Abstract 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.

Resumo Aditivos de tiouretano demonstraram melhorar propriedades de polímeros em diversas aplicações. O objetivo deste estudo foi verificar o efeito da adição de oligômeros de tiouretano, monômeros de acrilamida ou baseados em funcionalidade isobornil na propriedades físicas de bases de dentadura de acrílico polimerizadas em micro-ondas. O oligômero de tiouretano (TU) foi sintetizado e adicionado à resina acrílica em proporções variando de 3 a 14% em peso. Dimetil acrilamida (DMAM) e isobornil metacrilato (IBMA) foram adicionados em formulações separadas como plastificantes em concentrações variando de 5 a 20% em peso. As amostras foram polimerizadas usando energia de micro-ondas (500 Watts oor 3 min), desincluídas da mufla a temperature ambiente, armazenadas em água a 37°C por 24 h, e submetidas aos testes de: alteração dimensional linear, brilho, dureza Knoop, rugosidade superficial, resistência ao impacto, tensão normal de escoamento, módulo de elasticidade, tenacidade, viscosidade, temperatura de transição vítrea e heterogeneidade da rede polimérica, além de sorção de água e solubilidade. Os dados foram analisados com ANOVA e teste de Tukey (a=5%). A adição de TU não afetou ou diminuiu todas as propriedades, exceto pela estabilidade dimensional. O impacto nas propriedades foi estatisticamente significante para todos os materiais em concentrações acima de 20% de TU. Isso pode ser explicado por um encurtamento das cadeias e diminuição do empacotamento das cadeias lineares do PMMA. A adição de 5% de DMAM ou 10% de isobornil metacrilato melhoraram a tensão de escoamento e o módulo, mas aumentaram a sorção de água e solubilidade. Exceto pela estabilidade dimensional, a adição de oligômeros de tiouretano à bases de dentatura compostas por resina acrílica prejudicou todas a propriedades testadas. O uso de DMAM e isobornil metacrilato melhorou as propriedades para composições selecionadas.

Denture Bases , Microwaves , Surface Properties , Materials Testing , Polymethyl Methacrylate , Dental Materials , Polymerization
J. oral res. (Impresa) ; 9(2): 84-85, abr. 30, 2020. ilus
Article in English | LILACS | ID: biblio-1151829
J. oral res. (Impresa) ; 9(1): 72-80, feb. 28, 2020.
Article in English | LILACS | ID: biblio-1151506


Everyday use of denture cleansers to prevent microbial colonization on dentures can affect the properties of the denture base material. Limited literature is available on the effects of denture cleanser on reinforced resins. This study aimed to evaluate and compare the effect of denture cleanser on the flexural and impact strength of conventional and reinforced heat cure acrylic resins. Materials and Methods: Rectangular shaped specimens were prepared for flexural and impact strength as per ISO 1567. The denture base resins used included conventional, high impact, nylon fiber reinforced and glass fiber reinforced heat cure acrylic resins. They were further categorized into subgroups A and B depending on immersion in distilled water or denture cleanser (3.8% sodium perborate based). The flexural strength and impact strength of specimens were measured. The study design is a observational case-control study. SPSS version 25 statistical analysis software was used, and the STROBE statement checklist was followed. Results: The mean flexural strength was highest for glass fiber reinforced heat cure resin followed by conventional heat cure resin, high impact heat cure resin and nylon reinforced heat cure resin, respectively. The mean impact strength was highest for high impact heat cure resin followed by glass fiber reinforced heat cure resin, conventional heat cure resin, and nylon fiber-reinforced resin respectively.Conclusion: All the denture base resins tested exhibited a decrease in flexural and impact strength following use of a denture cleanser.

El uso diario de limpiadores para prótesis dentales para prevenir la colonización microbiana en las prótesis puede afectar las propiedades del material base de estas. Existe literatura limitada sobre los efectos de los limpiadores de prótesis sobre resinas reforzadas. Este estudio tuvo como objetivo evaluar y comparar el efecto de un limpiador de prótesis sobre la resistencia a la flexión y al impacto de las resinas acrílicas de curado con calor convencionales y reforzadas. Material y Métodos: Muestras de forma rectangular se prepararon para testear la resistencia a la flexión y al impacto según ISO 1567. Las resinas de base de prótesis utilizadas fueron resinas acrílicas convencionales, de alto impacto, y de curado térmico reforzadas con fibra de vidrio o nylon. Posteriormente se clasificaron en los subgrupos A y B según la inmersión en agua destilada o limpiador de prótesis (3,8% de perborato de sodio). Se midieron la resistencia a la flexión y la resistencia al impacto de las muestras. El diseño del estudio fue de un estudio observacional de casos y controles. Se utilizó el software de análisis estadístico SPSS versión 25, y se siguió la guía de la declaración STROBE. Resultado: La resistencia a la flexión fue más alta para la resina de curado por calor reforzada con fibra de vidrio seguida de la resina de curado por calor convencional, la resina de curado por calor de alto impacto y la resina de curado por calor reforzada con nylon, respectivamente. La resistencia al impacto fue más alta para la resina de curado por calor de alto impacto seguida de la resina de curado por calor reforzada con fibra de vidrio, la resina de curado por calor convencional y la resina reforzada con fibra de nylon, respectivamente. Conclusión: Todas las resinas de base de prótesis probadas exhibieron una disminución en la resistencia a la flexión y al impacto después del uso de un limpiador de prótesis.

Humans , Denture Bases , Denture Cleansers , Flexural Strength , Acrylic Resins , Dental Prosthesis
Braz. oral res. (Online) ; 34: e110, 2020. graf
Article in English | LILACS, BBO | ID: biblio-1132720


Abstract 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.

Candida albicans , Surface Properties , Acrylic Resins , Silicon Dioxide , Denture Bases
Braz. oral res. (Online) ; 34: e050, 2020. graf
Article in English | LILACS, BBO | ID: biblio-1132693


Abstract 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.

Terpenes/pharmacology , Candida albicans/drug effects , Biofilms/drug effects , Tea Tree Oil/pharmacology , Reference Values , Terpenes/chemistry , Acrylic Resins , Candida albicans/growth & development , Microbial Sensitivity Tests , Reproducibility of Results , Analysis of Variance , Statistics, Nonparametric , Microscopy, Confocal , Biofilms/growth & development , Tea Tree Oil/chemistry , Denture Bases/microbiology , Antifungal Agents/pharmacology
Int. j. odontostomatol. (Print) ; 13(3): 279-286, set. 2019. tab, graf
Article in English | LILACS | ID: biblio-1012423


ABSTRACT: The objective of this study was to compare the polymerization shrinkage of Eclipse photopolymerization resin for prosthesis based on urethane dimethacrylate (UDMA) with that of three heat-cured acrylic resins based on polymethyl methacrylate (PMMA) after the polymerization process and immersion in water. A total of 40 prostheses were fabricated on a standard metallic upper edentulous model: group 1, Eclipse; group 2, Triplex hot; group 3, Veracril; and group 4, Lucitone 199. Subsequently, the polymerization contraction was tested using a microscope in which measurements were made in micrometres at 3 points located in the middle parts of the right and left sides and the middle part of the palate at three time points once the prosthesis was completed, after 30 days of immersion in water for 8 hours a day at a temperature of 37 °C, and after cutting the prosthesis at the level of the second premolar. ANOVA revealed that the contraction of the polymerization no statistically significant differences between the groups, (P> 0.05). The type of resin and its interaction with the processing method behaves similarly for all test resins. The Veracril heat-cured resin obtained the lowest contraction value in the three measurements (mm) and the highest value was obtained with the Eclipse photopolymerization resin. The Eclipse resin exhibited no lower polymerization shrinkage compared to conventional acrylic resins based on polymethyl methacrylate (PMMA), however it was not significantly affected by immersion in water.

RESUMEN: El objetivo de este estudio fue comparar la contracción de polimerización de la resina de fotopolimerización Eclipse para prótesis basadas en dimetacrilato de uretano (UDMA) con la de tres resinas acrílicas curadas con calor a base de polimetacrilato de metilo (PMMA) después del proceso de polimerización e inmersión en agua. Se fabricaron un total de 40 prótesis en un modelo edéntulo superior metálico estándar: grupo 1, Eclipse; grupo 2, triplex caliente; grupo 3, veracril; y grupo 4, Lucitone 199. Posteriormente, la contracción de la polimerización se probó utilizando un microscopio en el que se realizaron mediciones en micrometros en 3 puntos ubicados en las partes medias de los lados derecho e izquierdo y la parte media del paladar en tres puntos de tiempo una vez la prótesis se completó, después de 30 días de inmersión en agua durante 8 horas al día a una temperatura de 37 °C, y después de cortar la prótesis a nivel del segundo premolar. ANOVA reveló que la contracción de la polimerización no presenta diferencias estadísticamente significativas entre los grupos, (P> 0,05). El tipo de resina y su interacción con el método de procesamiento se comportan de manera similar para todas las resinas de prueba. La resina curada con calor Veracril obtuvo el valor de contracción más bajo en las tres mediciones (mm) y el valor más alto se obtuvo con la resina de fotopolimerización Eclipse. La resina Eclipse no mostró una contracción de polimerización menor en comparación con las resinas acrílicas convencionales basadas en polimetilmetacrilato (PMMA), sin embargo, no se vio afectada significativamente por la inmersión en agua.

Composite Resins/chemistry , Resin Cements/chemistry , Dental Stress Analysis/methods , Denture Bases , Polymerization , Acrylic Resins , In Vitro Techniques , Hydrogel, Polyethylene Glycol Dimethacrylate , Dental Stress Analysis/instrumentation
J. oral res. (Impresa) ; 8(supl.1): 7-10, ago. 9, 2019. graf
Article in English | LILACS | ID: biblio-1141327


Objectives: Compare tensile and transverse strength of new copolymers for denture base. Materials and methods: The specimens were prepared from heat cured acrylic resin with three types of additives: Acryester B, Ethoxycarbonylethylene, and Propenoic acid at a percentage of 5% and 10%. The tensile and transverse strains were tested, recorded and compared. Results: The analysis of variance display statistically significant difference. The p-value was 0.001 for each of tensile and transverse strain tests. Conclusions: The tensile strength of the novel copolymers increased. The transverse strength of some of the novel copolymers increased.

Humans , Resins, Synthetic/chemistry , Tensile Strength , Denture Bases , Polymethyl Methacrylate
J. oral res. (Impresa) ; 8(supl.1): 24-27, ago. 9, 2019. tab, ilus
Article in English | LILACS | ID: biblio-1141502


This study assessed the effect of copolymerization on the microbiota of the oral cavity. The plant extraction was converted into aromatic derivatives, which were added to methyl methacrylate monomer. Fourier transform infrared spectroscopy spectra showed no negative effects of these additives on the polymerization process. All the assayed derivatives displayed some degree of antibacterial activity.

Humans , Eugenol/analysis , Denture Bases , Microbiota , Resins, Synthetic , Spectroscopy, Fourier Transform Infrared , Polymerization , Anti-Infective Agents/isolation & purification
Braz. dent. j ; 30(3): 266-271, May-June 2019. tab, graf
Article in English | LILACS | ID: biblio-1011545


Abstract The aim of this study was to verify whether modifications made in a hard chairside reline resin by an ethyl-cyanoacrylate adhesive, ECA (Super Bonder®, Loctite, Itapevi, SP, Brazil) would be able to inhibit or reduce Candida albicans biofilm formation on its surface, comparing to a commercial surface sealant (BisCover®, Bisco, Schaumburg, USA). Reline resin specimens were fabricated and randomly divided into 6 groups (n=8): CG (control group), no surface treatment; ECA1, ECA coating on the surface before sterilization; ECA2, ECA coating after sterilization; ECA3, ECA incorporated in the resin bulk; DPE1, BisCover® coating before sterilization; DPE2, BisCover® coating after sterilization. Specimens were inoculated with C. albicans SC5314 (1x107 cells/mL) and incubated for 24 h. Then, the biofilm were stained with LIVE/DEAD® BaclightTM L7007 Kit and analyzed by Confocal Laser Scanning Microscopy. The images were evaluated by bioImageL® v.2.0 software and total biovolume (µm3), viable cells (%), and covered area (%) were calculated. Data were statistically analyzed by Kruskal-Wallis and Dunn tests (p<0.05). Results showed that ECA-coated groups presented better results, reducing C. albicans biofilm formation. Acquired images revealed that these groups (ECA1 and ECA2) presented a reduced number of cells, mostly in yeast form (less pathogenic), while the other groups presented higher number of cells, mostly in hyphae form (more pathogenic). Based on these findings, a beneficial effect of Super Bonder® coating reline resins surface could be demonstrated, suggesting a promising way to prevent fungal biofilm formation on dentures.

Resumo O objetivo deste estudo foi verificar se as modificações feitas com o adesivo etil cianoacrilato, ECA (Super Bonder ®, Loctite, Itapevi, SP, Brasil) sobre as resinas acrílicas para reembasamento, poderiam inibir ou reduzir a formação de biofilmes de C.albicans sobre sua superfície quando comparado com um selante de superfície comercial (BisCover®, Bisco, Schaumburg, EUA). Amostras de resina acrílica para reembasamento foram fabricadas e divididas aleatoriamente em 6 grupos (n=8): CG (grupo controle), sem tratamento superficial; ECA1, revestimento de ECA na superfície antes da esterilização; ECA2, revestimento de ECA após esterilização; ECA3, ECA incorporado no volume da resina; DPE1, revestimento de BisCover® antes da esterilização; DPE2, revestimento de BisCover® após esterilização. Os espécimes foram inoculados com C. albicans SC5314 (1x107 células/mL) e incubados durante 24 h. Seguidamente, o biofilme foi corado com LIVE/DEAD® BaclightTM L7007 Kit e analisado no microscópio confocal de varredura a laser. As imagens foram avaliadas pelo software bioImageL® v.2.0, no qual foram calculados o biovolume total (μm3), as células viáveis (%) e a área coberta (%). Os dados foram analisados estatisticamente pelos testes de Kruskal-Wallis e Dunn (p<0,05). Os resultados mostraram que os grupos revestidos com ECA apresentaram os melhores resultados, reduzindo a formação do biofilme de C. albicans. As imagens adquiridas revelaram que esses grupos (ECA1 e ECA2) apresentaram um número reduzido de células, principalmente na forma de levedura (menos patogênico), enquanto os outros grupos apresentaram um maior número de células, principalmente na forma de hifas (mais patogênicas). Com base nessas descobertas, encontra-se um efeito benéfico na aplicação do adesivo ECA sobre as superfícies das resinas acrílicas para reembasamento, sugerindo assim uma nova alternativa de prevenir a formação de biofilme fúngico em próteses dentárias.

Candida albicans , Denture Bases , Surface Properties , Acrylic Resins , Brazil , Biofilms , Cyanoacrylates
Pesqui. bras. odontopediatria clín. integr ; 19(1): 4474, 01 Fevereiro 2019. tab, graf
Article in English | LILACS, BBO | ID: biblio-998256


Objective: To evaluate the change of diameter of different injection-molded thermoplastic materials. Material and Methods: Four thermoplastic injection-molded materials were analyzed (Bre.flex 2nd edition, Vertex ThermoSens, Perflex Biosens and Polyan IC). A total of 432 test samples were made in the form of an "hourglass". All samples were divided into three groups: Group I (Control) - consisting of 36 test samples for each type of material, that was not exposed to artificial aging or a wet environment; Group II - consisting of 36 test samples for each type of material, that were artificially aged through dehydration; Group III - specimen were subjected to artificial aging without dehydration. The diameter of each specimen was measured with a digital caliper. Data were analysed using the Student's t-test. Results: Regarding to shrinkage, the samples from the Bf Control group have a mean value of 1.56 mm and was observed a shrinkage of the injection-molded polyamide material within 0.25%. The comparison between the samples from Group II and Group III showed statistically significant differences (p<0.001). There were no significant differences between groups for Thermosens and Biosens (p>0.05). The comparison between Group II and Group III for Polyan IC samples shows that Group III has a higher arithmetic mean value (p<0.01). Conclusion: Shrinkage of the polymers during the injection process is present in all materials. The thermocycling and the storage in a dry or in a wet environment of the samples results in a change of the diameter in almost every single type of material.

Dental Prosthesis , Dental Impression Materials , Denture Bases , Material Resistance , Bulgaria , Data Interpretation, Statistical
J. appl. oral sci ; 27: e20180779, 2019. tab, graf
Article in English | LILACS, BBO | ID: biblio-1040232


Abstract Candida albicans is the main causative pathogen of denture stomatitis, which affects many complete denture patients. Objective: To evaluate the effect of different concentrations of nanodiamonds (NDs) added to polymethyl methacrylate (PMMA) denture base material on Candida albicans adhesion as well as on surface roughness and contact angle. Methodology: Acrylic resin specimens sized 10×10×3 mm3 were prepared and divided into four groups (n=30) according to ND concentration (0%, 0.5%, 1%, 1.5% by wt). Surface roughness was measured with a profilometer, and the contact angle with a goniometer. The effect of NDs on Candida albicans adhesion was evaluated using two methods: 1) slide count and 2) direct culture test. Analysis of variance (ANOVA) and Tukey's post hoc test were used in the statistical analyses. Results: Addition of NDs decreased the Candida albicans count significantly more than in the control group (p<0.05), with a lowest of 1% NDs. Addition of NDs also significantly decreased the surface roughness (p<0.05), but the contact angle remained the same. Incorporation of NDs into the PMMA denture base material effectively reduced Candida albicans adhesion and decreased surface roughness. Conclusion: PMMA/NDs composites could be valuable in the prevention of denture stomatitis, which is considered one of the most common clinical problems among removable denture wearers.

Humans , Acrylic Resins/chemistry , Candida albicans/drug effects , Polymethyl Methacrylate/chemistry , Denture Bases/microbiology , Nanodiamonds/microbiology , Nanodiamonds/chemistry , Reference Values , Stomatitis, Denture/microbiology , Stomatitis, Denture/prevention & control , Surface Properties , Materials Testing , Microscopy, Electron, Scanning , Reproducibility of Results , Analysis of Variance
Article in Korean | WPRIM | ID: wpr-761427


In edentulous patient, not only mastication and pronunciation but also esthetics are compromised. By restoring an edentulous patient with complete dentures, masticatory function and esthetics can be rehabilitated. The advantages of the dentures using CAD/CAM are that they can be reconstructed ubiquitously with stored data, and the strength and density of CAD/CAM material are clinically acceptable. In this clinical report, interocclusal record was taken in a conventional manner and then two lab processing procedures were performed: conventional method and CAD/CAM method. Two types of processing procedures were compared and evaluated. Fair clinical results were obtained in both ways, satisfying the patient.

Denture Bases , Denture, Complete , Dentures , Esthetics , Humans , Mastication , Methods
Article in English | WPRIM | ID: wpr-742071


PURPOSE: The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS: In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS: For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P < .05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION: Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

Denture Bases , Dentures , Hardness , Nylons , Polyesters , Solubility , Water
Article in English | WPRIM | ID: wpr-742068


PURPOSE: The accuracy of denture bases was compared among injection molding, milling, and rapid prototyping (RP) fabricating method. MATERIALS AND METHODS: The maxillary edentulous master cast was fabricated and round shaped four notches were formed. The cast was duplicated to ten casts and scanned. In the injection molding method, designed denture bases were milled from a wax block and fabricated using SR Ivocap injection system. Denture bases were milled from a pre-polymerized block in the milling method. In the RP method, denture bases were printed and post-cured. The intaglio surface of the base was scanned and surface matching software was used to measure inaccuracy. Measurements were performed between four notches and two points in the mid-palatal suture to evaluate inaccuracy. The palatine rugae resolution was evaluated. One-way analysis of variance was used for statistical analysis at α=.05. RESULTS: No statistically significant differences in distances among four notches (P>.05). The accuracy of the injection molding method was lower than those of the other methods in two points of the mid-palatal suture significantly (P < .05). The degree of palatine rugae resolution was significantly higher in the injection molding method than that in other methods (P < .05). CONCLUSION: The overall accuracy of the denture base is higher in milling and RP method than the injection molding method. The degree of fine reproducibility is higher in the injection molding method than the milling or RP method.

Denture Bases , Dentures , Fungi , Methods , Printing, Three-Dimensional , Sutures
J. appl. oral sci ; 26: e20170536, 2018. tab, graf
Article in English | LILACS, BBO | ID: biblio-954512


Abstract While the combined effect of microwave irradiation with cleansing solutions on denture base materials has been investigated, the effects of only using microwave irradiation and, more importantly, in a long-term basis, was not studied yet. Objective The purpose of this study was to evaluate the effect of a long-term repeated microwaving on the dimensional, color and translucency stability of acrylic and polyamide denture base materials. Material and Methods Thirty two specimens (32 mm x 10 mm x 2.5 mm) from polyamide (Valplast) and PMMA (Vertex Rapid Simplified) denture base materials were made. Eight specimens from each material were immersed in distilled water (control) and 8 were subjected to microwave exposure at 450 W for 3 minutes for a period simulating 224 days of daily disinfection. Linear dimension, color change (ΔE*) and translucency parameter (TP) were measured at baseline and after certain intervals up to 224 cycles of immersion, using a digital calliper and a portable colorimeter. The results were analysed using two-way repeated measures ANOVA to estimate possible differences among predetermined cycles and material type. Regression analysis was also performed to estimate the trend of changes with time. Statistical evaluations performed at a significance level of 5%. Results Data analysis showed significant changes in length at baseline with an increasing number of cycles (p<0.05) and a significant interaction of cycle-material (p<0.001). The ΔΕ* parameter was significantly higher with a higher number of cycles (p<0.001), but it did not vary between materials (p>0.05). TP decreased similarly in both materials following microwave action but in a significantly higher level for Valplast (p<0.001). Conclusions The results indicated that long-term repeated microwaving affects linear dimensional, color and translucency changes of both materials. Differences between PMMA and polyamide material were noted only in dimension and translucency changes.

Prosthesis Coloring , Polymethyl Methacrylate/radiation effects , Denture Bases , Microwaves , Nylons/radiation effects , Reference Values , Surface Properties , Time Factors , Materials Testing , Water/chemistry , Disinfection/instrumentation , Disinfection/methods , Reproducibility of Results , Analysis of Variance , Color , Colorimetry/methods , Polymethyl Methacrylate/chemistry , Interferometry/methods , Nylons/chemistry