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1.
Int J Nanomedicine ; 15: 9891-9907, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33328732

RESUMO

Purpose: The aim of this study was to investigate the effect of various mass fractions of 10-methacry-loyloxydecyl dihydrogen phosphate (MDP)-conditioned or unconditioned zirconia nano- or micro-particles with different initiator systems on the mechanical properties of nanohybrid resin composites. Methods: Both light-cured (L) and dual-cured (D) resin composites were prepared. When the mass fraction of the nano- or micro-zirconia fillers reached 55 wt%, resin composites were equipped with dual-cured initiator systems. We measured the three-point bending-strength, elastic modulus, Weibull modulus and translucency parameter of the nanohybrid resin composites containing various mass fractions of MDP-conditioned or unconditioned zirconia nano- or micro-particles (0%, 5 wt%, 10 wt%, 20 wt%, 30 wt% and 55 wt%). A Cell Counting Kit (CCK)-8 was used to test the cell cytotoxicity of the experimental resin composites. The zirconia nano- or micro-particles with MDP-conditioning or not were characterized by transmission electron microscopy (TEM), Fourier infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results: Resin composites containing 5-20 wt% MDP-conditioned or unconditioned nano-zirconia fillers exhibited better three-point bending-strength than the control group without zirconia fillers. Nano- or micro-zirconia fillers decreased the translucence of the nanohybrid resin composites. According to the cytotoxicity classification, all of the nano- or micro-zirconia fillers containing experimental resin composites were considered to have no significant cell cytotoxicity. The FTIR spectra of the conditioned nano- or micro-fillers showed new absorption bands at 1719 cm-1 and 1637 cm-1, indicating the successful combination of MDP and zirconia particles. The XPS analysis measured Zr-O-P peak area on MDP-conditioned nano- and micro-zirconia fillers at 39.91% and 34.89%, respectively. Conclusion: Nano-zirconia filler improved the mechanical properties of nanohybrid resin composites, but cannot be the main filler to replace silica filler. The experimental dual-cured composites can be resin cements with better opacity effects and a low viscosity.


Assuntos
Fenômenos Mecânicos , Nanopartículas/química , Zircônio/química , Resinas Compostas/química , Módulo de Elasticidade , Teste de Materiais , Metacrilatos/química , Fosfatos/química , Dióxido de Silício/química , Propriedades de Superfície
2.
Acta Odontol Latinoam ; 33(2): 59-68, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920607

RESUMO

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


Assuntos
Resinas Compostas/química , Peróxido de Hidrogênio/química , Clareadores Dentários/química , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Viscosidade/efeitos dos fármacos , Cor , Humanos , Teste de Materiais
3.
Niger J Clin Pract ; 23(8): 1103-1109, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788488

RESUMO

Background: Contamination is a common problem in pediatric restorative dentistry and there are a few studies that investigate blood contamination, hemostatic agents, and tooth dentin. Aim: The purpose of this study was to evaluate the effects of blood contamination and hemostatic agents on the bond strength of two different bonding systems with the dentin of primary teeth. Materials and Methods: Buccal and lingual dentin surfaces of 40 primary second molar teeth were used for this study. Specimens were divided into 4 groups according to the contamination and hemostatic agents (Blood-B, Ankaferd Blood Stopper-A, ViscoStat-V, Control-C) and then every group was further divided into two subgroups according to the bonding systems (Clearfil SE Bond-I, All Bond Universal-II, n = 10 per group). A bulk-fill composite resin was built-up on the surfaces. The specimens were tested in the micro shear mode at a crosshead speed of 1 mm/min on a universal test machine. Statistical analysis was performed with ANOVA and Tukey's tests at P < 0.05. Results: Significant differences have been detected in the micro shear bond strengths only between the Ankaferd Blood Stopper (ABS) (AI = 13.72 ± 4.47 and AII = 9.12 ± 4.4) and control groups (CI = 22.78 ± 10.86 and CII = 16.49 ± 6.55) without regards to the bonding systems. The highest scores were obtained in the control groups. Clearfil SE Bond showed better performance than All Bond Universal in all groups. Conclusion: It was determined that only the ABS contamination groups showed statistically significant decreases in the bond strengths when compared with control groups.


Assuntos
Sangue , Resinas Compostas/química , Colagem Dentária , Adesivos Dentinários/química , Hemostáticos/efeitos adversos , Análise do Estresse Dentário , Dentina , Humanos , Teste de Materiais , Dente Molar , Cimentos de Resina , Resistência ao Cisalhamento , Dente Decíduo
4.
Niger J Clin Pract ; 23(7): 957-964, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32620725

RESUMO

Aim: The aims of this study were to evaluate the surface morphology and surface roughness of restorative materials containing glass ionomer, analyze Streptococcus mutans biofilm formation on the surface of materials, and determine the correlation between surface roughness and biofilm. Materials and Methods: Four restorative materials: resin-modified glass ionomer; giomer; amalgomer; and glass carbomer were used and for each material, 6 mm in diameter and 2 mm in thickness disc-shaped specimens were prepared to evaluate the surface morphology (n = 3), surface roughness (n = 16), and biofilm (n = 20). Surface morphology was analyzed with a scanning electron microscope. Surface roughness was evaluated via an atomic force microscope. The biofilm was evaluated by counting the colony-forming units. Surface roughness measurements were evaluated using a one-way analysis of variance and Tukey HSD test. Biofilm parameters were analyzed using the Kruskal-Wallis H and Mann-Whitney U test. Pearson's correlation test was used to determine the correlation between surface roughness and biofilm. Results: While the highest roughness values were obtained for amalgomer and glass carbomer, the lowest roughness values belonged to giomer and resin-modified glass ionomer. Statistically significant differences in the number of adherent bacteria were observed between the materials only on day 1. No statistically significant correlation was determined between surface roughness and biofilm. Conclusions: The resin content and small filler particle size of material positively affect surface roughness. However, there is no direct relationship between surface roughness and biofilm.


Assuntos
Apatitas/química , Biofilmes/crescimento & desenvolvimento , Resinas Compostas/farmacologia , Placa Dentária/prevenção & controle , Cimentos de Ionômeros de Vidro/química , Streptococcus mutans/crescimento & desenvolvimento , Resinas Acrílicas , Resinas Compostas/química , Placa Dentária/microbiologia , Restauração Dentária Permanente , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Dióxido de Silício , Streptococcus mutans/efeitos dos fármacos , Propriedades de Superfície
5.
Niger J Clin Pract ; 23(6): 798-804, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32525114

RESUMO

Aims: The aim of this study was to evaluation the treatment success of the short post technique (mushroom restoration) using a composite resin in severely decayed primary anterior teeth after 6, 12, and 18 months after treatment. Methods: Eighteen children aged 3-5 years with severely decayed primary maxillary anterior teeth (60 anterior maxillary primary teeth in total) were included. Patients were treated under general anesthesia (GA). After pulpectomy, a "mushroom shape" was formed in the root canals for the purpose of retention, and the root canals were filled with zinc oxide-eugenol (ZOE), and the teeth were restored with composite resin. The status of treatment was evaluated clinically and radiographically for periapical radiolucency, pathological root resorption, marginal fracture, and loss of restoration for each treated tooth. All findings were recorded. Results: As a result of the evaluation criteria, the success rates at 6, 12 and 18 months were 86%, 80%, and 71%, respectively. None of the teeth showed apical radiolucency or pathological root resorption at the end of the 18th month period. Conclusion: The short-post (mushroom restorations) technique is a clinically acceptable alternative method for restoration of severely decayed primary teeth. This study supports the feasibility of treatment with this technique for pediatric patients treated under GA.


Assuntos
Restauração Dentária Permanente/métodos , Técnica para Retentor Intrarradicular , Pulpectomia/métodos , Materiais Restauradores do Canal Radicular/uso terapêutico , Dente Decíduo/cirurgia , Cimento de Óxido de Zinco e Eugenol/uso terapêutico , Anestesia Geral , Pré-Escolar , Resinas Compostas/química , Cárie Dentária/complicações , Preparo da Cavidade Dentária , Extravasamento de Materiais Terapêuticos e Diagnósticos/complicações , Feminino , Humanos , Masculino , Maxila , Pulpectomia/efeitos adversos , Reabsorção da Raiz , Traumatismos Dentários/complicações , Resultado do Tratamento
6.
Braz Oral Res ; 34: e045, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32401935

RESUMO

This in vitro study aimed to evaluate the effect of a silane-containing universal adhesive used with or without a silane agent on the repair bond strength between aged and new composites. Forty nanohybrid composite resin blocks were stored in distilled water for 14 d and thermo-cycled. Sandpaper ground, etched, and rinsed speciments were randomly assigned into four experimental groups: silane + two-step etch-and-rinse adhesive system, two-step etch-and-rinse adhesive system, silane + silane-containing universal adhesive system, and silane-containing universal adhesive system. Blocks were repaired using the same composite. After 24 h of water storage, the blocks were sectioned and bonded sticks were submitted to microtensile testing. Ten unaged, non-repaired composite blocks were used as a reference group to evaluate the cohesive strength of the composite. Two-way ANOVA and Tukey's tests were used to analyze average µTBS. One-way ANOVA and Dunnet post-hoc tests were used to compare the cohesive strength values and bond strength obtained in the repaired groups (α = 0.05). The µTBS values were higher for the silane-containing universal adhesive compared to the two-step etch-and-rinse adhesive system (p = 0.002). Silane application improved the repair bond strength (p = 0.03). The repair bond strength ranged from 39.3 to 65.8% of the cohesive strength of the reference group. Using universal silane-containing adhesive improved the repair bond strength of composite resin compared to two-step etch-and-rinse adhesive. However, it still required prior application of a silane agent for best direct composite resin repair outcomes.


Assuntos
Resinas Compostas/química , Cimentos Dentários/química , Cimentos de Resina/química , Silanos/química , Análise de Variância , Colagem Dentária/métodos , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo
7.
Niger J Clin Pract ; 23(5): 660-667, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32367873

RESUMO

Aims: The aim of this study is to investigate the color changes of three different traditional composites, one ceramic and two resin-based composites CAD/CAM blocks in different solutions. Methods: The materials used in the study were CAD/CAM block containing lithium disilicate glass ceramic (Ivoclar), Vita Enamic containing resin (VITA), Lava Ultimate Block containing resin (3M ESPE), G-aenial anterior composite (GC,), Filtek™ Ultimate Universal composite (3M ESPE) and Clearfil Majesty Esthetic composite (Kuaray). As colouring solutions, red wine (Buzbaǧ), black tea (Lipton), coffee (Nescafe) and distilled water (EAU distillee) were used. For the preparation of the traditional composite samples to be used in the study, 7 × 7 mm square-shaped plexiglass moulds, 1.2 mm in thickness, were used. The CAD/CAM blocks with ceramic and resin content were cut at the same thickness using a Struers sensitive cutting device. The samples were then randomly separated into grups of 10 and of the 240 samples, groups were separated into 6 different materials and 4 different solutions. The colour measurements of the 240 samples were taken at baseline, 30 days and 120 days with a Lovibond spectrophotometer (Tintometer). Results: A statistically significant difference was determined between the materials in respect of the ΔE values in the 30-day solution groups (P < 0.05). No statistically significant difference was determined in the ΔE values of the different materials in the 30-day and 120-day distilled water groups (P > 0.05). A statistically significant difference was determined between the materials in respect of the ΔE values in the 120-day solution groups (P < 0.05). Conclusion: In respect of discolouration, ceramic blocks are more successful. Resin-based blocks and traditional aesthetic composites showed more discolouration. The dietary habits of the patient should be taken into consideration in the selection of the restorative material.


Assuntos
Cerâmica/química , Materiais Dentários/química , Teste de Materiais/métodos , Cor , Resinas Compostas/química , Desenho Assistido por Computador
8.
Int. j interdiscip. dent. (Print) ; 13(1): 17-20, abr. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1114887

RESUMO

STATEMENT OF THE PROBLEM: The literature still lacks evidence regarding which polishing techniques have the ideal clinical outcomes for bulk-fill resin composites. PURPOSE: This study evaluated the surface gloss of two commercially available bulk-fill resin composites after different polishing procedures and characterized their micromorphology via scanning electron microscopy. MATERIAL AND METHODS: 80 bulk-fill compactable composite resin discs were created. The control group was left untreated, and remaining samples were subjected to different polishing techniques. Gloss units were measured and surface morphology of disc samples was assessed. The Tukey post-hoc test was used to identify any differences. RESULTS: Statistically significant differences were found between the different polishing systems applied to Filtek BulkFill Posterior and Tetric N Bulk-Fill. No differences were found when the same polishing system was applied for both resins. The highest gloss values were obtained in the control group and the ENA Shiny system; the lowest were obtained with SofLex XT and Soflex Spiral Wheels for the bulk-fill composite resins studied. CONCLUSIONS. Diamond pastes have the highest gloss behavior, followed by diamond rubber points. The systems with aluminum oxide discs present the lower gloss behavior. SEM images provided useful evidence, and future studies should include an evaluation over time.


Assuntos
Resinas Compostas/química , Polimento Dentário/métodos , Propriedades de Superfície , Teste de Materiais
9.
J Appl Oral Sci ; 28: e20190544, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348440

RESUMO

Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.


Assuntos
Força de Mordida , Resinas Compostas/química , Resinas Compostas/uso terapêutico , Restauração Dentária Permanente/métodos , Dente Molar , Dente não Vital/terapia , Criança , Força Compressiva , Tomografia Computadorizada de Feixe Cônico , Análise do Estresse Dentário , Módulo de Elasticidade , Análise de Elementos Finitos , Humanos , Modelagem Computacional Específica para o Paciente , Valores de Referência , Reprodutibilidade dos Testes , Resistência à Tração , Dente não Vital/diagnóstico por imagem , Resultado do Tratamento
10.
Braz Oral Res ; 34: e035, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32321053

RESUMO

Although fiber-reinforced composites are commonly used in dental practice, whether fiber-reinforced crowns and fixed partial dentures can be used as definitive prostheses remains to be determined. This study used scanning electron microscopy to evaluate the load-bearing capacity of non-reinforced and fiber-reinforced composite (FRC) molar crowns prepared by computer-aided design/computer-aided manufacturing (CAD/CAM). The crowns were fabricated from three empirical FRC blocks, one empirical composite block, and one commercial ceramic block. The FRC resin was prepared by mixing BaO silicate particles, E-glass fiber, and dimethacrylate resin. Specimens were divided into five groups (n = 10), differing in the amounts of filler, resin, and fiber. Crowns were statically loaded until fracture. One-way analysis of variance and Tukey's post hoc multiple comparison tests were used for statistical analyses. The groups showed significant differences in load-bearing capacity; empirical bidirectional FRC resin blocks had the highest capacity, while commercial ceramic blocks had the lowest capacity. Molar crowns formed from FRC resin blocks had higher load-bearing capacity compared to non-reinforced composite resin and ceramic blocks. These results show that fiber reinforcement increased the load-bearing capacity of molar crowns.


Assuntos
Resinas Compostas/química , Desenho Assistido por Computador , Coroas , Suporte de Carga , Análise de Variância , Cerâmica/química , Planejamento de Prótese Dentária , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Dente Molar , Valores de Referência , Reprodutibilidade dos Testes , Propriedades de Superfície
11.
Niger J Clin Pract ; 23(3): 322-328, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32134030

RESUMO

Objective: The aim of this in-vitro study was to investigate the effects of frequently consumed beverages on the color stability and microhardness of various restorative materials. Materials and Methods: Twenty-four samples were prepared in each group to examine the effect of different beverages on coloration and surface hardness of two direct composite resins (Filtek Z250, Filtek Z550); one indirect composite resin (Solidex); and one high viscosity glass ionomer cement (Equia Forte Fil). Samples were stored in four solutions (distilled water, black tea, coffee, and cola) at room temperature for 1 week (n = 6). The color values are taken at the beginning and the color and microhardness values taken at the end of 1 week were evaluated by the Kruskal-Wallis and Mann-Whitney U tests. Results: The highest color change was observed in the Equia Fil, while the least color change was observed in the Z550 group. The highest degree of color change was observed in coffee and cola groups. While the lowest values of hardness were observed in the Solidex group, the highest values of hardness were observed in the Z550 group. The highest levels of hardness change were detected in the coffee and cola groups. Conclusion: The color and hardness of restorative materials can be negatively affected by consumed beverages. Nanohybrid composite resins are resistant to external coloration and hardness change.


Assuntos
Bebidas Gaseificadas/efeitos adversos , Café/efeitos adversos , Cor , Resinas Compostas/química , Dureza , Chá/efeitos adversos , Descoloração de Dente , Materiais Dentários , Restauração Dentária Temporária , Cimentos de Ionômeros de Vidro , Testes de Dureza , Humanos , Teste de Materiais , Propriedades de Superfície
12.
Niger J Clin Pract ; 23(3): 355-361, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32134035

RESUMO

Objectives: This study evaluated the effect of Er, Cr: YSGG laser irradiation at different powers on repair bond strength (RBS) between ceramic restoration and composite resin (CR). Materials and Methods: Sixty ceramic samples were prepared and thermocycled for 2,500 cycles between 5°C and 55°C. Samples randomly divided into six groups (n = 10) according to the different surface treatment: control group (no surface treatment), 9.6% hydrofluoric acid etching, 37% phosphoric acid etching, and irradiations with Er, Cr: YSGG lasers (1 to 3W). The Cimara System was applied to all samples surface according to the manufacturer's instructions. CR resin was built-up on each ceramic surface using a tygon tube. The RBS test was performed at a crosshead speed of 1 mm/min, and one sample of each group was also observed under SEM and EDS was used to measure the elemental profiles of each specimen. Data was analyzed with one-way ANOVA and Tukey HSD test. Results: The lowest RBS was recorded in Group OF, and the highest RBS was recorded in Group HF, followed by Group 3W. There was no statistical difference between Group Control, 1W and 2W. Furthermore, differences in RBSs between Group 3W and the other groups except Group 2W were significant (P < 0.05). In EDS analysis, there are evident differences between surface treated samples and controls. Conclusions: 3W laser irradiation may be an alternative method to acid etching for enhancing the RBS of CR to ceramic.


Assuntos
Cerâmica/química , Resinas Compostas/química , Lasers de Estado Sólido , Teste de Materiais , Propriedades de Superfície
13.
BMC Oral Health ; 20(1): 30, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000753

RESUMO

BACKGROUND: Increased composite roughness enhances bacterial adhesion and discoloration, thus increasing the risk of gingival inflammation and secondary caries. Concerns about detrimental effects of sodium bicarbonate on surface roughness influenced the development of less abrasive powders: a glycine-based powder and an erythritol-based powder, additionally - sodium bicarbonate-based powder of reduced grain size. However, there is limited evidence on effects of these materials on the surface of dental fillings. The aim of the present study was to compare the effects of three air-polishing powders (of a reduced abrasiveness) on surface roughness of microhybrid restorative composite material. MATERIAL AND METHODS: Microhybrid light-cure resin composite samples were placed on 64 plaster cubes and light-cured through polyester strips. Surface roughness was measured using laser confocal microscope (magnification 2160x). The specimens were randomly divided into three groups (n = 20, 20 and 24) and air-polished with: sodium bicarbonate (40 µm), glycine (25 µm) and erythritol (14 µm), respectively. Then surface roughness was remeasured, keeping the same field of observation. Specialized 3D analysis software was used for data processing. Parameters according to ISO 25178: Sa, Sq, Sku, Sp, Sv, Sz, Ssk were used to describe surface roughness. RESULTS: Sa, Sq, Sp, Sv, Sz increased significantly following air polishing. Ssk was significantly higher, whereas Sku was significantly lower in sodium bicarbonate and erythritol groups than before air polishing. Comparison between the three powders revealed that Sa was significantly higher in sodium bicarbonate group than in glycine group. Sku was significantly higher in glycine and erythritol groups than in sodium bicarbonate group. CONCLUSIONS: Sodium bicarbonate has a stronger detrimental effect on composite surface than glycine or erythritol. No advantage of erythritol comparing to glycine could be found.


Assuntos
Resinas Compostas , Materiais Dentários/química , Polimento Dentário/métodos , Bicarbonato de Sódio/química , Pressão do Ar , Resinas Compostas/química , Humanos , Teste de Materiais , Pós , Propriedades de Superfície
14.
Molecules ; 25(4)2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32075084

RESUMO

Coating technology can be applied to decorate building constructions. Alkali-activated materials (AAM) are promising green and durable inorganic binders which show potential for development as innovative coating. In the paper, the possibility of using AAM composited with starch (CMS) as a novel plastic formable inorganic coating for decorating in building was investigated. The rheological properties, including plastic viscosity, yield stress, and thixotropy were considered to be critical properties to obtain the working requirements. Four different mixtures were systematically investigated to obtain the optimum formulation, and then were used to study their hardened properties, such as mechanical strengths (compressive, flexural, and adhesive strength), drying shrinkage, cracking behavior, and microstructure. Study results found that CMS could quickly and efficiently be hydrolyzed in an alkaline solution to produce organic plastic gel which filled in AAM paste, leading to the significant improvement of coating consistency, plastic viscosity, and thixotropy. The optimum coating composited with 15.40 wt% CMS shows a relatively stable rheological development, the setting time sufficient at higher than 4 h. Furthermore, CMS shows a significant positive effect on the cracking and shrinkage control due to padding effect and water retention of CMS, which results in no visible cracks on the coating surface. Although the mechanical strength development is relatively lower than that of plain AAM, its value, adhesive strength 2.11 MPa, compressive strength 55.09 MPa, and flexural strength 8.06 MPa highly meet the requirements of a relevant standard.


Assuntos
Materiais Revestidos Biocompatíveis/química , Resinas Compostas/química , Plásticos/química , Amido/química , Álcalis/química , Compostos Inorgânicos/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração
15.
Braz Oral Res ; 34: e001, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32022221

RESUMO

This study analyzed the effect of prior application of copaiba oil (CO) emulsions as a dentin cleaning substance on microleakage and microtensile adhesive strength. Twenty-five premolars and sixty-four molars were used for microleakage and microtensile assays. For the microleakage assays, specimens with standard class V cavities were divided (n = 5), according to the tested CO emulsions: CO10%X, CO10%Y, and CO10%Z, as well as chlorhexidine 2% (CHX) and distilled water (DW), as positive and negative controls, respectively. Restorations were performed using the Adper Single Bond® and/or Clearfil SE Bond® systems. Cervical, occlusal, distal and mesial sections were assessed for tracer penetration degree at the composite/tooth interface. For the microtensile assay, healthy molars were divided into sixteen groups, in which artificial caries were induced in half of the groups. Dentin surfaces were treated with CO10%X and CO10%Y, CHX and DW. Microtensile bond strength was measured by fixing each sample to the plate of a universal testing machine operated at a speed of 0.5 mm/minute until failure. Dentin treated with CO10%X showed a lower infiltration rate than dentin treated with the other CO emulsions, CHX2% and DW. According to the microtensile assay, both healthy and affected dentin treated with CO10%X and Adper Single Bond® adhesive system presented higher adhesive strength. CO emulsion, used as a dentin biomodifier, interfered positively in microleakage and improved adhesive strength after acid etching in the Adper Single Bond® adhesive system, or before applying the Clearfil SE Bond® self-etching system.


Assuntos
Colagem Dentária/métodos , Adesivos Dentinários/química , Dentina/efeitos dos fármacos , Fabaceae/química , Óleos Vegetais/química , Análise de Variância , Clorexidina/química , Resinas Compostas/química , Cimentos Dentários/química , Infiltração Dentária , Dentina/química , Emulsões/química , Humanos , Teste de Materiais , Reprodutibilidade dos Testes , Cimentos de Resina/química , Estatísticas não Paramétricas , Propriedades de Superfície , Resistência à Tração
16.
Braz Oral Res ; 34: e005, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32022224

RESUMO

The purpose of this study was to evaluate the effect of ionizing radiation from high energy X-ray on fluoride release, surface roughness, flexural strength, and surface chemical composition of the materials. The study groups comprised five different restorative materials: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer, and Fuji IX GP. Twenty disk-shaped specimens (8x2 mm) for fluoride release and 20 bar-shaped specimens (25 x 2x 2 mm) for flexural strength were prepared from each material. Each material group was divided into two subgroups: irradiated (IR) and non-irradiated (Non-IR). The specimens from IR groups were irradiated with 1.8 Gy/day for 39 days (total IR = 70.2 Gy). The amount of fluoride released into deionized water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours and on days 2, 3, 7, 15, 21, 28, 35, and 39 (n = 10). The flexural strength was evaluated using the three-point bending test (n = 10). After the period of measurement of fluoride release, seven specimens (n = 7) from each group were randomly selected to evaluate surface roughness using AFM and one specimen was randomly selected for the SEM and EDS analyses. Data were analyzed with two-way ANOVA and Tukey tests (p = 0.05). The irradiation significantly increased fluoride release and surface roughness for Amalgomer CR and Zirconomer groups (p < 0.05). No significant change in flexural strength of the materials was observed after irradiation (p > 0.05). The ionizing radiation altered the amount of fluoride release and surface roughness of only Amalgomer CR and Zirconomer. The effect could be related to the chemical compositions of materials.


Assuntos
Apatitas/efeitos da radiação , Bis-Fenol A-Glicidil Metacrilato/efeitos da radiação , Resinas Compostas/efeitos da radiação , Fluoretos/química , Cimentos de Ionômeros de Vidro/efeitos da radiação , Radiação Ionizante , Zircônio/efeitos da radiação , Análise de Variância , Apatitas/química , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Resistência à Flexão , Cimentos de Ionômeros de Vidro/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Valores de Referência , Reprodutibilidade dos Testes , Espectrometria por Raios X , Estatísticas não Paramétricas , Propriedades de Superfície/efeitos da radiação , Fatores de Tempo , Zircônio/química
17.
Niger J Clin Pract ; 23(1): 18-25, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31929202

RESUMO

Aim: This study evaluated the microtensile bond strength (MTBS) of an orthodontic adhesive to water-aged composite surfaces using different surface treatments. Subjects and Methods: Twelve composite blocks (10 mm × 10 mm × 5 mm) were fabricated and randomly divided into two groups. Half of the specimens were stored in distilled water for 1 day, and the other specimens were stored for 30 days. The specimens were randomly assigned to six groups according to surface treatments (n = 15): Group 1, control (no treatment); Group 2, phosphoric acid; Group 3, diamond bur; Group 4, diamond bur + phosphoric acid; Group 5, laser; and Group 6, laser + phosphoric acid. One coat of orthodontic adhesive was bonded to one surface of composite blocks, and a microhybrid composite resin was bonded to the surfaces via a Teflon mold. Bond strength was evaluated using an MTBS test. Surface topography was evaluated using scanning electron microscopy (SEM) analysis. The data were analyzed using one-way analysis of variance, Tamhane post-hoc test, and independent sample t-tests (P < 0.05). Results: Bond strength values tended to decrease in all groups (with the exception of Group 2) after storage in water for 30 days (P < 0.05). Laser and diamond bur application (with or without phosphoric acid) enhanced the bond strength. Conclusions: An Er,Cr:YSGG laser application may be a feasible alternative to diamond bur for enhancing the bond strength of orthodontic adhesive to composite resin.


Assuntos
Resinas Compostas/química , Colagem Dentária , Cimentos Dentários/química , Lasers de Estado Sólido/uso terapêutico , Resistência à Tração , Água/química , Resinas Compostas/uso terapêutico , Análise do Estresse Dentário , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Ácidos Fosfóricos/química , Resistência ao Cisalhamento , Propriedades de Superfície
18.
Niger J Clin Pract ; 23(1): 110-115, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31929216

RESUMO

Objective: The aim of this study was to compare to effect of phototherapy and surface flattening after immediately bleaching on the shear bond strength to bleached enamel. Methods: Ninety-six human upper incisors were divided into 4 groups (n = 24). Group NB: no bleached, group P: phototherapy with YSGG laser, group F: 0.5 mm surface flattening, group PF: 0.5 mm surface flattening and phototherapy with Er;Cr:YSGG laser. Then, each group was assigned to 2 subgroups according to adhesive mode (n = 12) as; subgroup S (self-etching mode), subgroup T (total-etching mode) which are universal adhesives. All surface conditionings and restorations were performed with composite resin materials immediately after bleaching. Shear bond strength test was performed by using universal testing machine. The surfaces were also evaluated with SEM. The data were statistically analyzed with one-way ANOVA post-hoc Tukey tests. Results: The lowest SBS values were achieved in FS (13.72 ± 2.29) while the highest ones in PT (28.01 ± 6.81). However, the differences were not significant (P > 0.05). All surface conditioning methods provided SBS values similar to the control (P > 0.05). All subgroups of self-etching mode were significantly lower than their total-etching counterparts (P < 0.05). Conclusions: The present study showed that surface removal and phototherapy have a potential clinical application for eliminate to undesirable effect of bleaching treatment. Surface conditioning with either flattening and/or phototherapy may provide clinicians to restore bleached teeth at the same visit with bleaching and reduce chair-time.


Assuntos
Adesivos/farmacologia , Colagem Dentária/métodos , Esmalte Dentário/efeitos dos fármacos , Corrosão Dentária/métodos , Lasers de Estado Sólido/uso terapêutico , Fototerapia , Resistência ao Cisalhamento , Clareamento Dental , Condicionamento Ácido do Dente/métodos , Resinas Compostas/química , Materiais Dentários/química , Humanos , Teste de Materiais , Clareamento Dental/métodos
19.
Nat Commun ; 11(1): 373, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953388

RESUMO

The layered architecture of stiff biological materials often endows them with surprisingly high fracture toughness in spite of their brittle ceramic constituents. Understanding the link between organic-inorganic layered architectures and toughness could help to identify new ways to improve the toughness of biomimetic engineering composites. We study the cylindrically layered architecture found in the spicules of the marine sponge Euplectella aspergillum. We cut micrometer-size notches in the spicules and measure their initiation toughness and average crack growth resistance using flexural tests. We find that while the spicule's architecture provides toughness enhancements, these enhancements are relatively small compared to prototypically tough biological materials, like nacre. We investigate these modest toughness enhancements using computational fracture mechanics simulations.


Assuntos
Materiais Biocompatíveis , Materiais Biomiméticos/química , Resinas Compostas/química , Resistência à Flexão , Poríferos/química , Animais , Fenômenos Biomecânicos , Cerâmica/química , Dureza , Teste de Materiais , Modelos Teóricos , Nácar/química , Estresse Mecânico , Propriedades de Superfície
20.
Braz Oral Res ; 33: e121, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939500

RESUMO

The objective of the study was to analyze the surface area (SA) of the wear caused by simulated chewing on human enamel and opposing restorative material, namely: composite resin (CR), porcelain fused to metal (PFM), lithium disilicate (LD), or monolithic zirconia (MZr). Forty-eight premolars were selected as enamel specimens and divided randomly into 4 groups (n = 48; n =12) used as antagonists in chewing simulation (250,000 loading cycles) against one of the four selected test materials. Enamel and material specimens were scanned and evaluated under digital microscope, and wear SA (mm2) were recorded. Descriptive statistics, paired t-test, one-way ANOVA, and post-hoc Tukey-HSD tests were used for statistics (p < 0.05). The smallest and largest SA were exhibited by enamel against LD (0.80 mm2) and PFM (1.74 mm2), respectively. PFM (3.48 mm2) showed the largest SA and CR (2.28 mm2) showed the smallest SA. Paired t-test for SA values showed significant difference (p < 0.05) in all wear comparisons between materials and enamel antagonists. The wear of materials were greater than that of their respective enamel antagonists (p < 0.05). One-way ANOVA of the logarithmic means of wear SA revealed significant differences (P<0.05). Post-hoc Tukey test revealed significance for PFM (p < 0.05) with other materials. Wear of all test materials was greater compared to the wear of enamel antagonists. PFM and LD caused the largest and the smallest enamel wear, respectively. CR, LD, and MZr are more resistant than PFM to wear after simulated chewing against enamel.


Assuntos
Resinas Compostas/química , Esmalte Dentário/química , Porcelana Dentária/química , Mastigação , Ligas Metalo-Cerâmicas/química , Desgaste dos Dentes/etiologia , Zircônio/química , Adolescente , Adulto , Análise de Variância , Polimento Dentário/métodos , Humanos , Processamento de Imagem Assistida por Computador , Teste de Materiais , Microscopia/instrumentação , Valores de Referência , Estatísticas não Paramétricas , Propriedades de Superfície , Adulto Jovem
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