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1.
J Contemp Dent Pract ; 21(1): 22-27, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381796

RESUMO

INTRODUCTION: This is an in vitro study to evaluate the degree of conversion (DC) of nanoceramic and microhybrid composites activated by different polymerization modes at different intervals. AIM: To determine the DC of two resin composites at different time intervals and modes of polymerization on DC. MATERIALS AND METHODS: Two commercially available composite resins-nanoceramic (Ceram X, Dentsply) and microhybrid (Spectrum TPH, Dentsply)-were used in this study. A total of 80 cylindrical samples (n = 40 each) were made by packing the composites in one increment into (5 × 2 mm) Teflon molds and cured using a light-emitting diode (LED) at an irradiance of 1,200 mW/cm2. Each group was further divided into two groups (n = 20) based on the curing modes (20 seconds, 40 seconds). These 20 samples were further subdivided (n = 10) based on the time interval (2 days, 7 days). Degree of conversion was assessed by Fourier-transform infrared spectrophotometer (FTIR) using a direct technique (attenuated total reflectance) on the top surface of the samples. Degree of conversion was measured for samples cured for 20 seconds (n = 10) and 40 seconds (n = 10) after 2 days and 7 days during which the samples were stored in an incubator at 37°C, 90% ± 10% relative humidity. The results obtained were statistically analyzed using two-way and three-way analysis of variance (ANOVA) test and p value set at (<0.005) significance level. RESULTS: Degree of conversion for the tested composites varied between 44% and 55% for Ceram X and 42% and 45% for Spectrum TPH. A significant difference was observed in DC for Ceram X samples for different polymerization modes (20 seconds and 40 seconds) as well as at 2-7 days measurement, whereas Spectrum TPH did not show any significant difference for polymerization modes. CONCLUSION: Ceram X demonstrated high DC values compared with that of Spectrum TPH with regard to two different polymerization modes. CLINICAL SIGNIFICANCE: Lesser the time required for conversion and less the residual monomer left, better is the prognosis of the restoration, and better is the patient satisfaction.


Assuntos
Resinas Acrílicas , Resinas Compostas , Poliuretanos , Análise de Variância , Humanos , Teste de Materiais , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier
2.
Swiss Dent J ; 130(5): 390-396, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32267138

RESUMO

The objective of this paper was the analysis of the 1-year outcome of teeth treated with apical surgery and a recently introduced bioceramic root repair material (BCRRM) for root-end filling. Patients were consecutively enrolled from 2015 to 2017. Apical surgery included the modern technique, i.e. the use of a surgical microscope, ultrasonic preparation of a root-end cavity, and retrofilling with BCRRM. The cohort comprised 150 patients with 174 treated teeth. Patients were recalled one year after surgery for a clinical and radiographic re-examination. Three experienced observers evaluated the periapical radiographs with regard to periapical healing utilizing the healing criteria established by Rud et al. (1972) and Molven et al. (1987). Based on the clinical findings and the radiographic assessment, healing was judged as successful, uncertain, or failed. Study parameters included gender, age, type of treated tooth, and type of BCRRM (regular vs. fast set putty). At the 1-year follow-up, 170 teeth could be reexamined (drop-out rate 2.3%). Healing outcome was categorized as successful in 94.1%, uncertain in 4.1%, and failed in 1.8%. No significant differences were observed when comparing the success rates among the different subcategories of study parameters. The lowest success rate was noted in mandibular premolars (86.7%) but without reaching statistical significance. In conclusion, BCRRM appears to be a biocompatible root-end filling material showing excellent 1-year results. The success rate was similar to recently reported success rates for BCRRM in apical surgery.


Assuntos
Materiais Restauradores do Canal Radicular , Resinas Acrílicas , Seguimentos , Humanos , Obturação do Canal Radicular , Resultado do Tratamento
3.
An Acad Bras Cienc ; 92(1): e20181120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32321020

RESUMO

the focus ofthis study was to testthe hypothesisthatthere would be no difference betweenthe biocompatibility of silicon dioxide nanofilms used as antimicrobial agents. Sixty male Wistar rats were divided into 4 groups (n=15): Group C (Control,Polyethylene), Group AR (Acrylic Resin), Group NP (Acrylic Resin coated with NP-Liquid), Group BG (Acrylic Resin coated with Bacterlon).the animals were sacrificed with 7,15 and 30 days and tissues analyzed as regardsthe events of inflammatory infiltrate, edema, necrosis, granulation tissue, mutinucleated giant cells, fibroblasts and collagen. Kruskal-Wallis and Dunn tests was used (P<0.05). Intense inflammatory infiltrate was shown mainly in Groups BG and AR, with significant difference from Control Group inthe time interval of 7days (P=0.004). Necrosis demonstrated significant difference between Group BG and Control Group (P<0.05) inthe time intervals of 7 days. For collagen fibers,there was significant difference betweenthe Control Group and Groups AR and BG inthe time interval of 7 days (P=0.006), and between BG and Control Groups inthe time intervals of 15 days (P=0.010).the hypothesis was rejected. Bacterlon demonstratedthe lowest level, and NP-Liquid Glassthe highest level of tissue compatibility, and best cell repair.the coating with NP-Liquid Glass was demonstrated to be highly promising for clinical use.


Assuntos
Resinas Acrílicas/farmacologia , Materiais Biocompatíveis/farmacologia , Edema/induzido quimicamente , Necrose/induzido quimicamente , Dióxido de Silício/farmacologia , Tela Subcutânea/patologia , Resinas Acrílicas/química , Animais , Materiais Biocompatíveis/química , Edema/patologia , Masculino , Teste de Materiais , Modelos Animais , Necrose/patologia , Ratos , Ratos Wistar , Dióxido de Silício/química , Tela Subcutânea/efeitos dos fármacos
4.
Water Sci Technol ; 81(2): 301-308, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32333663

RESUMO

The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 106 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0-52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 107 Da, 11.2-17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 106 to 6.45-7.42 × 105 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 107 to 3.76-5.87 × 106 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 105 and 5.68 × 105 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.


Assuntos
Resinas Acrílicas , Reatores Biológicos , Anaerobiose , Biodegradação Ambiental , Peso Molecular
5.
Int J Nanomedicine ; 15: 717-728, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099360

RESUMO

Background: Kefiran is a useful polysaccharide made of branched glucogalactose which is produced by microorganisms. Here the anti-MCF-7 breast cancer cells activity of kefiran and cytokine productions (IL-6) of peripheral blood mononuclear cells (PBMC) treated by kefiran was studied. Also, the effect of using kefiran as a useful and cost-effective scaffold in neural stem cell culture (PC12 cell culture) was investigated. Material and Methods: Kefiran was produced from raw milk with 0.5% fat and 10 g of kefir grains. After incubation for 48 hrs at room temperature, the solvent collected (crude kefiran). These samples were kept at 100°C for 1 hr (boiled kefiran) and the supernatant was precipitated by ethanol (pure kefiran). Then, the electrospun nanofibers, pure polyacrylonitrile (PAN), PAN/kefiran 5%, and PAN/kefiran 10% were fabricated and used as scaffolds in the cell culture. The structure of fabricated was studied by SEM and the cytokine production (IL-6) in vitro in the cell culture supernatant of PBMC line after treatment with kefiran (1mg/mL, 5 mg/mL) and kefiran-PAN 5% and 10% were carried out by enzyme-linked immunosorbent assay (ELISA). The attachment of PC12 cells was examined by inverted microscope. Also, cytotoxicity of kefiran for PC12 and MCF7 cells and morphological changes of PC12 cells were evaluated by MTT and Cresyl violet staining (Nissl staining) respectively. Results: The mean diameter of fabricated PAN/kefiran 5% and 10% nanofibers were 310.2±43.97 nm. The contact angle measurement results (26.9± 1.9 for the pure PAN scaffold vs 12.3± 1.13 for the PAN/kefiran) revealed enhanced hydrophilicity of scaffolds upon the incorporation of kefiran and PAN. Seeding of PC12 cells on the scaffolds showed that fabrication of kefiran into PAN led to the enhancement of cell attachment, proliferation, and morphological changes. Also, the promotion of PBMC growth and decreasing of MCF7 cell lines viability were shown through MTT assay. No significant changes were measured for the level of IL-6 in PAN/kefiran 5% treated cells compared to the control (p ≥ 0.05). Conclusion: These results suggest superior properties of kefiran/PAN nanofibrous scaffolds for the neural stem cell culture especially for repairing injured spinal cord. Also, the pure kefiran could be used for the enhancement of PBMC growth and reducing the MCF7 cancerous cells growth. So, using biocompatible, anti-bacterial, and anti-tumor kefiran/PAN nanofibers for regenerative medicine seems promising.


Assuntos
Resinas Acrílicas/química , Neoplasias da Mama/patologia , Técnicas de Cultura de Células/métodos , Citocinas/biossíntese , Leucócitos Mononucleares/metabolismo , Nanofibras/química , Polissacarídeos/química , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Leucócitos Mononucleares/efeitos dos fármacos , Células MCF-7 , Nanofibras/ultraestrutura , Células PC12 , Poliésteres/química , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier , Engenharia Tecidual/métodos , Tecidos Suporte/química
6.
Pharm Res ; 37(3): 35, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31950282

RESUMO

PURPOSE: Epicutaneous immunotherapy (EPIT) involving the skin's immune system is easy to use, painless and has a low risk of systemic side effects; it can be applied to food allergies that have a high morbidity rate in children. In this study, we evaluated the safety and efficacy of hydrophilic gel patch (HG) for EPIT. METHODS: Milk protein concentrate (MPC)-containing HG was applied to the skin that maintained a barrier function or formed puncture holes with microneedle, and MPC-specific antibodies were measured. The clinical study was conducted involving patients with severe milk allergy. RESULTS: No specific immune response was induced when immunizing to intact skin, and antibody production was observed by forming puncture holes. It was suggested that MPC contained in HG has immunogenicity and a very small amount of MPC was delivered to intact skin. In the clinical study, the symptom induction threshold increased in four of eight subjects, allowing them to consume milk and switch to oral immunotherapy. Although local skin reactions and temporary elevation of specific IgE antibodies were observed, no systemic side effects appeared throughout the study. CONCLUSIONS: EPIT using HG is a safe method to enable oral administration even in patients with severe milk allergies.


Assuntos
Resinas Acrílicas/química , Imunoglobulina E/imunologia , Hipersensibilidade a Leite/imunologia , Proteínas do Leite/imunologia , Adesivo Transdérmico , Administração Cutânea , Animais , Bovinos , Criança , Pré-Escolar , Modelos Animais de Doenças , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Imunoglobulina E/análise , Imunoterapia , Masculino , Camundongos , Microinjeções , Proteínas do Leite/administração & dosagem , Agulhas , Projetos Piloto , Pele/metabolismo , Resultado do Tratamento
7.
Int J Oral Maxillofac Implants ; 35(1): 100-106, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923292

RESUMO

PURPOSE: To test a novel implant metal-acrylic prosthesis design in comparison to a conventional prosthesis design through simulation of cyclic masticatory loading. The novel design involved digital designing and fabrication of the framework and the matched veneering acrylic resin material. MATERIALS AND METHODS: Ten prostheses were fabricated for each group. All the prostheses exhibited a similar external design on two implants with a distal cantilever. The conventional group comprised a milled metal framework with mechanically retained acrylic denture teeth via vertical pins. The digital prosthesis group incorporated an inverted T-shape bar and a monolithic milled acrylic resin veneer. The resin veneer was subsequently adhesively attached on the bar. All prostheses were thermally aged and subjected to laboratory cyclic loading at the cantilever region. The load-to-failure and the number of cycles until failure were collected. Furthermore, failed specimens were analyzed to determine the mode of failure. RESULTS: The digital prostheses failed at significantly greater load-to-failure (1,570.0 N ± 116.0 N) and number of cycles (124,857 ± 21,608) than the conventional prostheses (load-to-failure = 1,015.0 N ± 47.4 N; number of cycles = 28,452 ± 6,559). The conventional prostheses failed by fracturing of the acrylic teeth and veneering material that led to exposure of the metal framework. Half of the digital prostheses failed by superficial chipping of the veneering material, while the other half failed by the deformation and fracture of screws. CONCLUSION: Within the limitations of this study, the digital prostheses with the novel design and monolithic veneering material showed significantly higher strength compared with the conventional prostheses. The mode of acrylic failure of the digital prostheses was more favorable.


Assuntos
Prótese Dentária Fixada por Implante , Facetas Dentárias , Resinas Acrílicas , Falha de Restauração Dentária , Teste de Materiais , Metais
8.
J Photochem Photobiol B ; 203: 111741, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31901721

RESUMO

Spinal cord injury (SCI) is a distressing injury and an irretrievable dramatic event that can debilitate victims for lifespan. Recovery and treatment of SCI is critical challenges for medicine, to overcome the hurdles stem cells and hydrogel scaffolds implantation is a boon for SCI recovery. In this regard, we reported the synthesis of Gold nanoparticles (Au NPs) loaded Agarose/Poly (N-isopropylacrylamide) (PNIPAM) as promising materials for SCI treatment. Herein, Au NPs was synthesized by well-established citrate reduction method and the prepared materials were characterised by UV-visible spectroscopy (UV-vis), Transmission electron microscopy (TEM), Fourier- transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and EDAX analysis. The microscopic images showed an elliptical or ovoid porous structure nature of hydrogel, and successful and homogenous loading of photo plasmonic nanoparticles into the hydrogel structure. The in vitro cell viability and inflammation analyses data exhibited that prepared hydrogels have no toxic to the cells and displayed high anti-regenerative ability with bone marrow Mesenchymal stem cells (MSCs) and macrophages cells. The in vivo analysis study demonstrated that the treated materials with encapsulated MSCs have greater nerve tissue regeneration efficacy which was confirmed by the results of BBB scores. The hind limb locomotion of treated model animals was totally vanished after post-operational surgery. It's established that implanted nano-hydrogel materials combined with MSCs have quicker recovery of motor function after post-operative surgery, when compared to the other implanted animal groups.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Transplante de Células-Tronco Mesenquimais , Nanopartículas Metálicas/química , Traumatismos da Medula Espinal/terapia , Bexiga Urinária/fisiopatologia , Resinas Acrílicas/química , Animais , Células da Medula Óssea/citologia , Ouro/química , Membro Posterior/fisiologia , Locomoção , Células-Tronco Mesenquimais/química , Células-Tronco Mesenquimais/citologia , Tecido Nervoso/fisiologia , Regeneração , Traumatismos da Medula Espinal/complicações , Traumatismos da Medula Espinal/patologia , Tecidos Suporte/química
9.
Arch Oral Biol ; 111: 104643, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918345

RESUMO

AIM: To evaluate the cytotoxicity and inflammatory response of different types of provisional restorative materials to mice gingival fibroblasts. METHODS: Cytotoxicity of provisional material discs (thermal-polymerized acrylic resin; auto-polymerized acrylic resin; bisacrylic resin; nano-ceramic resin for CAD/CAM and prefabricated polymer block for CAD/CAM) to Mice (Balb/c) gingival cell were investigated under direct and indirect contact (extracts) at 24, 48 and 72 h, using the MTT and Alamar blue assays. Materials extracts (24 h) were applied to the cell culture (indirect contact) or cells were seeded on discs of provisional materials, and the cytotoxicity and production of IL-6, IL-1ß and TNF-α after 24, 48 and 72 h were analyzed through MTT, Alamar Blue® and ELISA. Culture medium was used as control for indirect contact assay (extract) and the surfaces of the wells without discs of provisional materials were used as control for direct contact assay. Results were analysed statistically by ANOVA followed by the Bonferroni-Test correction. Statistically significant differences were considered if P was < .05. RESULTS: Auto-polymerized and bisacrylic resins (direct contact) reduced cell viability after 24, 48 and 72 h compared to control (P < .05). Indirect contact (extract) was not cytotoxic to cells at all periods compared to control (P > .05). Auto-polymerized and bisacrylic resins increased IL-6, IL-1ß and TNF-α levels mainly at 24 h when compared to the other materials (P < .001). CONCLUSION: Auto-polymerized and bisacrylic were more cytotoxic to mice gingival fibroblasts. CAD/CAM nano ceramic resin and prefabricated polymer blocks are more predictable materials to preserve the periodontal soft tissues.


Assuntos
Resinas Acrílicas , Materiais Dentários , Animais , Cerâmica , Resinas Compostas , Desenho Assistido por Computador , Teste de Materiais , Camundongos , Propriedades de Superfície
10.
J Appl Oral Sci ; 28: e20190039, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939520

RESUMO

OBJECTIVE: This study aimed to evaluate the physical properties and antifungal activities of polymethyl methacrylate (PMMA) acrylic resins after the incorporation of chlorhexidine diacetate salt (CDA). METHODOLOGY: First, acrylic resin specimens were fabricated with Vipi Cor® and DuraLay® resins with and without the incorporation of 0.5%, 1.0% or 2.0% CDA. The residual monomer and CDA release were measured at intervals ranging from 2 hours to 28 days using ultraviolet spectrometry combined with high-performance liquid chromatography. The antifungal activity against C. albicans was evaluated with the agar diffusion method. Fourier transform infrared spectroscopy was used to analyze the degree of resin conversion. Finally, the water sorption values of the resins were also measured. RESULTS: The incorporated CDA concentration significantly changed the rate of CDA release (p<0.0001); however, the brand of the material appeared to have no significant influence on drug release. Subsequently, the inhibition zones were compared between the tested groups and within the same brand, and only the comparisons between the CDA 2% and CDA 1% groups and between the CDA 1% and CDA 0.5% groups failed to yield significant differences. Regarding the degrees of conversion, the differences were not significant and were lower only in the CDA 2% groups. Water sorption was significantly increased at the 1.0% and 2.0% concentrations. CONCLUSIONS: We concluded that the incorporation of CDA into PMMA-based resins enabled the inhibition of C. albicans growth rate, did not alter the degrees of conversion of the tested resins and did not change the release of residual monomers.


Assuntos
Antifúngicos/química , Clorexidina/análogos & derivados , Polimetil Metacrilato/química , Resinas Acrílicas/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Clorexidina/química , Clorexidina/farmacologia , Cromatografia Líquida de Alta Pressão , Teste de Materiais , Polimetil Metacrilato/farmacologia , Valores de Referência , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Água/química
11.
Dent Mater ; 36(3): 377-386, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31992486

RESUMO

OBJECTIVE: This work focuses on the influence of poly(acrylic acid) (PAA) architecture (linear or branched) on setting behavior and compressive strength of glass ionomer cements (GICs). METHODS: Branched and linear poly(acrylic acid)s were synthesized according to the Strathclyde methodology or by free radical polymerization. They were characterized by 1H-NMR spectroscopy and size exclusion chromatography to determine their molecular weight and size distribution. GIC setting was characterized by oscillating rheometry and time-dependent FTIR spectroscopy. In addition, compressive strength was tested on cylindrical samples (6 × 4 mm; n = 8/cement composition) after storage in deionized water at 37 °C for one day. RESULTS: We used two different routes to prepare PAA. One direct route in order to provide straightforward access to branched PAA and a two-step approach in order to get more control about the PAA molecular weight using tert-butyl acrylate (tBA) for polymerization with subsequent deprotection. Using the second approach we obtained several linear PAA of which a mixture was used in order to mimic the molecular weight and size distribution of branched PAA. This allowed the direct comparison of properties relying only on the polymer architecture. Comparing linear PAA to branched samples in general led to faster setting but at the same time decreased the compressive strength. Increasing molecular weight of branched PAA resulted in even faster GIC setting while increasing compressive strength and this correlates well with the trends reported for linear PAA in literature. Mixing of branched and linear PAA, however, turned out to be an effective way of tailoring GIC properties. SIGNIFICANCE: our results suggest that both molecular weight and dispersity need to be considered when choosing suitable PAA architecture for obtaining specific GIC properties.


Assuntos
Resinas Acrílicas , Cimentos de Ionômeros de Vidro , Força Compressiva , Teste de Materiais
12.
Anal Bioanal Chem ; 412(7): 1629-1637, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31965245

RESUMO

A new magnetic molecularly imprinted nanofiber (MMIN) nanocomposite was prepared and used to the selective extraction of nilotinib. MMIN was constructed using a novel and general method including a combination of molecular imprinting and electrospinning technology. By electrospun precursor nanofibers containing polyacrylonitrile, Fe3O4 magnetic nanoparticles, and nilotinib as the template, molecularly imprinted nanofibers were produced with a mean diameter of 500 nm and lengths up to several millimeters. The microstructure and morphology of the prepared MMIN were thoroughly investigated using techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The MMIN was then used to the extraction of nilotinib. The extracted nilotinib was re-extracted and determined spectrofluorimetrically at the excitation and emission wavelengths of 271 and 335 nm, respectively. The relation between fluorescence signal for the re-extracted solution and nilotinib concentration was linear in the range 0.01-10.0 mg L-1 (n = 9) and the RSD for the determination of 1.0 and 5.0 mg L-1 nilotinib 2.75% and 1.09% (n = 3), respectively. The detection limit of the method was obtained as 0.002 mg L-1 nilotinib. The results indicated that the proposed method can be successfully applied to the determination of nilotinib in human serum samples. Graphical abstract.


Assuntos
Magnetismo , Impressão Molecular , Nanofibras , Pirimidinas/isolamento & purificação , Resinas Acrílicas/química , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Pirimidinas/sangue , Reprodutibilidade dos Testes , Espectrometria de Fluorescência
13.
Oper Dent ; 45(1): 104-110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31567055

RESUMO

OBJECTIVES: The purpose of this study was to evaluate the properties (fracture toughness, surface hardness) of newer conventional glass-ionomer restorative materials that are marketed for posterior stress-bearing areas compared with more traditional glass-ionomer restorative materials marketed for non-load-bearing areas and composite-resin restorative materials. METHODS AND MATERIALS: Notched-beam fracture toughness specimens were created in a mold with each tested material (Equia Forte, GC America, with and without a surface coating of Equia Forte Coat; Ketac Universal, 3M/ESPE; ChemFil Rock, Dentsply; Fuji IX GP Extra, GC; Ionostar Molar, VOCO; Filtek Z250, 3M/ESPE; Filtek Supreme Ultra, 3M/ESPE) and fractured using a universal testing machine after 24 hours of storage. Hardness values were determined on the surface of the fracture toughness specimens using a hardness tester. Data were analyzed with a one-way ANOVA and Tukey's post hoc test per property (alpha=0.05). RESULTS: The composite-resin restorative materials had significantly greater fracture toughness than the glass-ionomer materials. There was no significant difference in fracture toughness between the glass-ionomer materials. The use of a resin coating significantly increased the surface hardness of the newer glass ionomer marketed for stress-bearing areas. CONCLUSIONS: Fracture toughness was not improved with the newer glass-ionomer restorative materials marketed for stress-bearing areas compared to the conventional glass-ionomer materials, however a resin coating provided greater surface hardness.


Assuntos
Resinas Compostas , Cimentos de Ionômeros de Vidro , Resinas Acrílicas , Materiais Dentários , Teste de Materiais , Dióxido de Silício , Propriedades de Superfície
14.
J Prosthet Dent ; 123(2): 291-298, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31202554

RESUMO

STATEMENT OF PROBLEM: The performance of a recently introduced overdenture attachment system after cyclic dislodgement is not known. PURPOSE: The purpose of this in vitro study was to compare a conventional attachment system and a recently introduced attachment system for their dislodgement forces before and after cyclic dislodgement. MATERIAL AND METHODS: Three acrylic resin models were fabricated with 2 implant analogs (4.1 mm; Zimmer Dental) in different angulations; parallel in the first, divergent by 30 degrees in the second, and divergent by 60 degrees in the third model. Six acrylic resin blocks containing 2 metal housings of 2 different LOCATOR attachments (LOCATOR Legacy [LL], R-Tx, n=3; Zest Dental Solutions) were also fabricated. LOCATOR abutment pairs (LL and R-Tx) were placed onto the analogs. Seven specimens for LL and R-Tx with pink attachments were tested for dislodgement forces, and the values were recorded before and after 1440 times (simulated 1-year use) of cyclic dislodgement using an occlusal loading simulator machine. A 3-way ANOVA was used for dislodgement force comparison before and after cyclic dislodgement for different angulations and for 2 different LOCATOR attachments. Any significant differences were identified with the Tukey HSD test (α=.05). The percentage decrease in the dislodgement force was also calculated. RESULTS: A significant 3-way interaction was found for the LOCATOR type, implant angle, and time (P<.001). LOCATOR type made a difference for only parallel and 60 degree-divergent implants before cyclic dislodgement (P≤.022). After cyclic dislodgement, a significant effect of the LOCATOR type on dislodgement force was found for only parallel implants (P=.034). In both LOCATOR systems, the dislodgement force was different (P<.001) among different implant angulations, except for parallel to 30-degree comparison, before and after cyclic dislodgement. For both LL and R-Tx, significant differences (P≤.022) were found between before and after cyclic dislodgement for all angulations except LL in parallel (P=.214). CONCLUSIONS: When implants were parallel, initially, the dislodgement force of R-Tx was higher than that of LL; however, the forces were similar after cyclic dislodgement. When implants were divergent by 30 degrees, there were no differences between the dislodgement forces of the LOCATOR systems before and after cyclic dislodgement. When implants were divergent by 60 degrees, initially, the dislodgement force of LL was higher than that of R-Tx; however, the forces were similar after cyclic dislodgement. Before and after cyclic dislodgement, in each system, dislodgement forces were greater when implants were divergent by 60 degrees than when parallel and 30 degrees. After cyclic dislodgement, dislodgement forces decreased for both systems, except for LL when the implants were parallel.


Assuntos
Implantes Dentários , Revestimento de Dentadura , Resinas Acrílicas , Prótese Dentária Fixada por Implante , Análise do Estresse Dentário , Retenção de Dentadura
15.
J Prosthodont Res ; 64(1): 78-84, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31147297

RESUMO

PURPOSE: We investigated the effects of denture adhesives (cream (Cr), powder (Po), and cushion (Cu)) on growth and adhesive-related morphological transformation of Candida albicans. For this purpose, the numbers of adherent C. albicans, hyphae-specific gene expressions, and the SEM images were examined. METHODS: Acrylic resin blocks were prepared as controls (Co). Cr, Po, and Cu were thinly spread on the surface of the resin block.C. albicans suspension was seeded on the specimens and incubated at 4 °C for 2 h. The numbers of C. albicans adhering to each specimen at each incubation time period (1, 2, 3, 6, 12, and 24 h) were quantified using real-time RT-PCR. The hyphae-specific genes expressions were examined. The surface of each specimen was observed under the SEM to detect the transformation to the hyphal form. RESULTS: The initial adhesion rates in all groups were not statistically significant. The numbers of C. albicans adhering increased with time in all groups, and those adhering to the Cr, Po, and Cu were significantly greater than that adhering to the Co. In the Cr and Po, the hyphal-specific genes expressions were higher after incubation for 6 h. The transformation to the hyphal form was identified in the Cr and Po after incubation for 6 and 12 h. CONCLUSIONS: The denture adhesives used in this study accelerated the growth of C. albicans. Moreover, the early transformation to the hyphal form on the Cr- and Po-type adhesives was observed, suggesting that we should carefully use Cr- and Po-type adhesives.


Assuntos
Candida albicans , Bases de Dentadura , Resinas Acrílicas , Biofilmes , Cimentos Dentários
16.
J Prosthet Dent ; 123(1): 173-180, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31027950

RESUMO

STATEMENT OF PROBLEM: No information is available on roughness and stainability of acrylic resins polymerized by experimental microwave cycles after immersion in stainable liquids and simulated brushing. PURPOSE: The purpose of this in vitro study was to evaluate the effect of stainable drinks and brushing on roughness and stainability of acrylic resins (Vipi Cril [CA] and Vipi Wave [MA]) polymerized with different cycles. MATERIAL AND METHODS: CA and MA specimens (n=5; diameter, 20 mm; thickness, 3 mm) were made using 4 methods recommended by the manufacturer (water bath polymerization and microwave polymerization cycles) and experimental at 550 W or 650 W for 3 or 5 minutes (M550/3 and M650/5), respectively. After storage in distilled water at 37°C for 48 hours (T0), the specimens were stored in water, coffee, or red wine (37°C) for 36 days with simulated brushing (54 000 cycles, T1). Roughness (Ra) and stainability (ΔE/National Bureau of Standards) were measured at T0 and T1. Roughness and stainability data were analyzed by 3-way repeated measures and 2-way ANOVA, respectively, followed by the Bonferroni test (α=.05). RESULTS: After storing in coffee and brushing, CA showed the highest (M550/3=2.33 ±0.72 µm) and the lowest roughness (water bath polymerization=1.22 ±0.58 µm), whereas roughness of MA specimens processed by M650/5 increased (1.57 ±0.59 µm). Storing in wine and brushing increased roughness (1.75 ±0.32 µm) in the M550/3 group. No staining was observed on MA after brushing regardless of the polymerization cycle. All values were acceptable (ΔE≤3.3), except for MA (microwave polymerization), which showed National Bureau of Standards=4.49 (appreciable change) after storing in wine and brushing. CONCLUSIONS: A slight increase in material roughness was observed after staining and brushing. Only MA polymerized following manufacturer cycles showed relevant stainability after immersion in wine and brushing.


Assuntos
Resinas Acrílicas , Escovação Dentária , Teste de Materiais , Micro-Ondas , Polimerização , Propriedades de Superfície
17.
J Prosthet Dent ; 123(1): 181.e1-181.e7, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31813582

RESUMO

STATEMENT OF PROBLEM: Candida adherence to the denture base is an important cause of denture stomatitis. In addition, infections with drug-resistant Candida have become more prevalent, especially among elderly and immunocompromised patients. Thus, alternative safe antifungal agents for oral applications are needed. PURPOSE: The purpose of this in vitro study was to investigate the activity of chitosan, a natural biopolymer, against common oral Candida species and its efficacy in inhibiting C albicans adherence to denture-base acrylic resin. MATERIAL AND METHODS: The minimum fungicidal concentrations (MFCs) of 5 types of chitosan against 6 species of Candida and 10 C albicans clinical isolates were determined by broth and agar dilution, respectively. N-succinyl chitosan (NSC), low- and high-molecular-weight water-soluble chitosan (LMWC and HMWC), and oligomer and polymer shrimp-chitosan were examined. NSC and HMWC, as pure gel and as a mixture with carboxymethylcellulose (CMC), were applied to acrylic resin disks, incubated with C albicans for 24 hours, and washed, and adherent cells were collected for colony count. The effects of HMWC on human gingival fibroblasts after 1 and 24 hours of treatment were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The retention force of HMWC gel was measured by using a universal testing machine. The Kruskal-Wallis and Mann-Whitney U tests were used to compare the antiadherence activity (α=.05). RESULTS: HMWC had the highest antifungal activity against most Candida species tested and C albicans clinical isolates. HMWC gel completely inhibited C albicans adherence to denture base acrylic resin (P<.001). CMC denture adhesive significantly increased C albicans adherence (P<.001), but adding 2×MFC HMWC into CMC reduced the adherence, although this was not statistically significant (P=.06). HMWC at 1×MFC and 2×MFC showed no toxic effect on gingival fibroblast viability and proliferation. Moreover, the retention force provided by HMWC gel was sufficient for use as a denture adhesive (>5000 Pa). CONCLUSIONS: High-molecular-weight, water-soluble chitosan is a biocompatible biopolymer that could inhibit C albicans adherence and that showed properties suitable for development into an antifungal denture adhesive.


Assuntos
Quitosana , Estomatite sob Prótese , Resinas Acrílicas , Idoso , Antifúngicos , Candida , Candida albicans , Cimentos Dentários , Bases de Dentadura , Humanos
18.
J Prosthet Dent ; 123(1): 183.e1-183.e5, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31767202

RESUMO

STATEMENT OF PROBLEM: Studies assessing the comparative denture base adaptation performance of the pour technique for various palatal vault depths are sparse. PURPOSE: The purpose of this in vitro study was to investigate the denture base adaptation performance of the pour technique compared with other conventional fabrication techniques (light-polymerization, injection, compression molding) for shallow and deep palatal vault depths. MATERIAL AND METHODS: Edentulous maxillary study models with 2 palatal vault depths were prepared. Based on the power analysis, the sample size of each conventional fabrication technique was 12 (N=96). After denture bases for each technique had been fabricated on the casts according to the manufacturers' recommendations, the casts and the intaglio surfaces of the denture bases were scanned by using a laboratory scanner (InEos X5). The standard tessellation language (STL) files of the casts and the intaglio surfaces of acrylic resin bases were transferred into a software program (Romexis, version 5.0), and the software superimposed each cast and its corresponding denture base scan with the reference pyramids semi-automatically. After superimposition, the mean gap distances (mm) were calculated by using the software and recorded from the identified 4 specific regions (denture border apex, palate, ridge crest, and posterior palatal seal). A statistical analysis was performed by using the 3-factor factorial ANOVA. Post hoc comparisons among the subgroups were performed by using the Tukey HSD test. RESULTS: Two- and 3-way interactions among palatal vault depth, polymerization technique, and location variables were statistically significant (P<.05). For shallow palatal vault depth, injection and pour polymerization techniques demonstrated similar mean gap distances irrespective of location (P>.05). The light-polymerization technique showed the highest mean gap distances among the tested polymerization techniques in all regions except for the posterior palatal seal area (P<.05). CONCLUSIONS: The pour technique showed similar denture base adaptation to compression molding and injection. Light-polymerization exhibited the highest mean gap distance between the denture base and the cast for both palatal vault depths for most of the locations. A deep palatal vault depth led to inferior denture base adaptation performance for light-polymerization in the ridge crest and compression molding in the posterior palatal seal location.


Assuntos
Bases de Dentadura , Planejamento de Dentadura , Resinas Acrílicas , Palato , Polimerização
19.
J Prosthodont ; 29(1): 80-86, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31650649

RESUMO

PURPOSE: To evaluate the effect of protective coatings on the surface roughness, contact angle, and Candida albicans (C. albicans) adhesion to polymethyl methacrylate (PMMA) denture base materials. MATERIAL AND METHODS: A total of 560 rectangular heat- and autopolymerized acrylic resin specimens were fabricated and divided into 5 groups (n = 14/group) according to coating agent. Uncoated specimens were used as control. Coating materials were: nano-coat, Optiglaze, nano-silica, or cyanoacrylate. Surface roughness (Ra ) was evaluated using a profilometer. Contact angle measurements were performed using the sessile drop method. C. albicans adhesion was evaluated using direct culture and slide count methods. ANOVA and Tukey's post hoc tests were used for data analysis (α = 0.05). RESULTS: Nano-coat and Optiglaze coating of heat-polymerized acrylic significantly decreased Ra (p < 0.001). No significant effect was seen with nano-silica coating while Ra significantly increased with cyanoacrylate (p < 0.001). For autopolymerized acrylic, nano-coat, Optiglaze, and nano-silica coatings significantly decreased Ra in comparison to control group (p < 0.001) while no significant difference was seen between control and cyanoacrylate coating (p = 0.45). In comparison to control group, nano-coat, Optiglaze, and nano-silica coating for both denture base materials significantly decreased contact angle, and C. albicans adhesion (p < 0.001) while cyanoacrylate significantly increased C. albicans adhesion (p = 0.002) with no effect on contact angle for heat- (p = 1.00) and autopolymerized resins (p = 0.83). CONCLUSION: Coating of removable prosthesis with nano-coat, Optiglaze, or nano-silica is an effective method to reduce C. albicans adhesion.


Assuntos
Candida albicans , Bases de Dentadura , Resinas Acrílicas , Teste de Materiais , Polimetil Metacrilato , Propriedades de Superfície
20.
J Urol ; 203(2): 378, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31661382
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