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1.
Braz Oral Res ; 34: e020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236317

RESUMO

This in vitro study aimed to assess the effects of different pretreatments used to adapt glass-fiber posts cemented to root canals with different resin cements, regarding porosity percentage and bond strength. Twelve bovine incisor roots were prepared with Largo drills. After post space preparation, the specimens were randomized into two types of pretreatment groups (n = 3): water-wet bonding and ethanol-wet bonding. After the post were cemented, the roots were stored in 100% humidity at room temperature for 7 days. The samples were scanned by microcomputed tomography (micro-CT). Images were reconstructed by NRecon software, and CTAn software was used to analyze the porosity percentage (%) at the luting interface. Evaluation of the push-out bond strength was performed by serially cutting the roots, and submitting the slices to testing. Additionally, the resin cement post-gel shrinkage values (%) were measured using the strain-gauge method (n = 10). Data were analyzed by two-way ANOVA, Tukey's test and Student's t test (a = 0.05). The roots prepared with ethanol-wet bonding using RelyX™ U200 had significantly lower porosity in the coronal and apical thirds (p < 0.05). The group prepared with ethanol-wet bonding using RelyX™ ARC presented better bond strength results in the coronal and apical thirds (p < 0.05). RelyX™ ARC (0.97%) produced a higher post-gel shrinkage value than RelyX™ U200 (0.77%). Canals pretreated with ethanol-wet bonding presented better outcomes in regard to porosity percentage and push-out bond strength.


Assuntos
Adesivos Dentinários/farmacologia , Etanol/farmacologia , Técnica para Retentor Intrarradicular , Cimentos de Resina/química , Raiz Dentária/efeitos dos fármacos , Animais , Bovinos , Colagem Dentária , Materiais Dentários/química , Cavidade Pulpar , Vidro , Teste de Materiais , Porosidade , Irrigantes do Canal Radicular/química , Microtomografia por Raio-X
2.
Life Sci ; 248: 117460, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32092331

RESUMO

AIM: This study determined the optimum gamma irradiation dosage to sterilize sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT) and CNT functionalized with HY (HY-SWCNT and HY-MWCNT), evaluated the structural integrity of the materials and assessed whether sterilized materials kept biological properties without affecting renal function. MAIN METHODS: Materials were submitted to dosages of 100 gγ to 30 Kgγ and plated onto agar mediums for colony forming units (CFUs) counting. Sterilized samples were inoculated with 107Bacillus clausii, submitted again to gamma irradiation, and plated in agar mediums for CFUs counting. Scanning electron microscope was used for structural evaluation of sterilized materials. Tooth sockets of rats were treated with sterilized materials for bone formation assessment and renal function of the animals was analyzed. KEY FINDINGS: The optimum gamma dosage for sterilization was 250 gγ for HY and 2.5 Kgγ for the other materials without meaningful structural changes. Sterilized materials significantly increased bone formation (p < 0.05) and they did not compromise renal function and structure. SIGNIFICANCE: Gamma irradiation efficiently sterilized HY, SWCNT, MWCNT, HY-SWCNT and HY-MWCNT without affecting structural aspects while maintaining their desirable biological properties.


Assuntos
Materiais Dentários/efeitos da radiação , Raios gama , Ácido Hialurônico/efeitos da radiação , Nanotubos de Carbono/efeitos da radiação , Osteogênese/efeitos dos fármacos , Alvéolo Dental/efeitos dos fármacos , Animais , Bacillus clausii/efeitos da radiação , Contagem de Colônia Microbiana , Materiais Dentários/química , Materiais Dentários/farmacologia , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Testes de Função Renal , Masculino , Dente Molar/cirurgia , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Ratos , Ratos Wistar , Esterilização/métodos , Extração Dentária/métodos , Alvéolo Dental/microbiologia , Alvéolo Dental/fisiologia , Alvéolo Dental/cirurgia , Cicatrização/efeitos dos fármacos
3.
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
4.
J Appl Oral Sci ; 28: e20190042, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31778443

RESUMO

INTRODUCTION: Gap formation of composite resin restorations is a serious shortcoming in clinical practice. Polymerization shrinkage stress exceeds the tooth-restoration bond strength, and it causes bacterial infiltration within gaps between cavity walls and the restorative material. Thus, an intermediate liner application with a low elastic modulus has been advised to minimize polymerization shrinkage as well as gap formation. OBJECTIVE: The purpose of this in vitro study was to assess gap formation volume in premolars restored with different bulk-fill composites, with and without a resin-modified glass-ionomer cement (RMGIC) liner, using x-ray micro-computed tomography (micro-CT). METHODOLOGY: Sixty extracted human maxillary premolars were divided into six groups according to bucco-palatal dimensions (n=10). Standardized Class II mesio-occluso-distal cavities were prepared. G-Premio Bond (GC Corp., Japan) was applied in the selective-etch mode. Teeth were restored with high-viscosity (Filtek Bulk Fill, 3M ESPE, USA)-FB, sonic-activated (SonicFill 2, Kerr, USA)-SF and low viscosity (Estelite Bulk Fill Flow, Tokuyama, Japan)-EB bulk-fill composites, with and without a liner (Ionoseal, Voco GmbH, Germany)-L. The specimens were subjected to 10,000 thermocycles (5-55°C) and 50,000 simulated chewing cycles (100 N). Gap formation based on the volume of black spaces at the tooth-restoration interface was quantified in mm3 using micro-computed tomography (SkyScan, Belgium), and analyses were performed. Data were analyzed using repeated-measures ANOVA and the Bonferroni correction test (p < 0.05). RESULTS: The gap volume of all tested bulk-fill composites demonstrated that Group SF (1.581±0.773) had significantly higher values than Group EB (0.717±0.679). Regarding the use of a liner, a significant reduction in gap formation volume was observed only in Group SFL (0.927±0.630) compared with Group SF (1.581±0.773). CONCLUSION: It can be concluded that different types of bulk-fill composite resins affected gap formation volume. Low-viscosity bulk-fill composites exhibited better adaptation to cavity walls and less gap formation than did sonic-activated bulk-fill composites. The use of an RMGIC liner produced a significant reduction in gap formation volume for sonic-activated bulk-fill composites.


Assuntos
Resinas Compostas/química , Preparo da Cavidade Dentária/métodos , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Imageamento Tridimensional/métodos , Polimerização , Análise do Estresse Dentário , Humanos , Técnicas In Vitro , Teste de Materiais , Cimentos de Resina , Microtomografia por Raio-X
5.
Mater Sci Eng C Mater Biol Appl ; 106: 110167, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753414

RESUMO

New inventions and innovations in the field of dentistry have potential applications to satisfy the patient's demand. In prosthodontics, a dental prosthesis plays a major role in improving the quality of oral health care. Currently, the trends have shifted towards the implants and implant-supported prosthesis for the replacement of missing teeth. Conventional dentures are patient's preference mainly due to financial constraints. In an attempt to find solutions to current problems, we have come across new materials zirconium, titanium and new inventions like flexible dentures, fenestrated dentures, and CAD/CAM fabricated dentures. Using the progress of past five years in the field of prosthodontics, this comprehensive review focuses on denture base materials, denture liners, removable partial dentures, fixed prosthesis such as crown and bridge materials, implant-supported a fixed denture, artificial teeth materials, impression materials, and ingenious alternatives to conventional dentures. This article also sheds some light on the current promising researches and gives insight into the problems that can be the focus of future researches.


Assuntos
Prótese Dentária Fixada por Implante , Coroas , Materiais Dentários/química , Planejamento de Prótese Dentária , Prótese Parcial Removível , Humanos , Zircônio/química
6.
PLoS One ; 14(12): e0226528, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31851701

RESUMO

The processing and characterization of hybrid PMMA resin composites with nano-zirconia (ZrO2) and electrospun polystyrene (PS) polymer fibers were presented in this study. Reinforcement was selected with the intention to tune the physical and mechanical properties of the hybrid composite. Surface modification of inorganic particles was performed in order to improve the adhesion of reinforcement to the matrix. Fourier transform infrared spectroscopy (FTIR) provided successful modification of zirconia nanoparticles with 3-Methacryloxypropyltrimethoxysilane (MEMO) and bonding improvement between incompatible inorganic nanoparticles and PMMA matrix. Considerable deagglomeration of nanoparticles in the matrix occurred after the modification has been revealed by scanning electron microscopy (SEM). Microhardness increased with the concentration of modified nanoparticles, while the fibers were the modifier that lowers hardness and promotes toughness of hybrid composites. Impact test displayed increased absorbed energy after the PS electrospun fibers had been embedded. The optimized composition of the hybrid was determined and a good balance of thermal and mechanical properties was achieved.


Assuntos
Acrilatos/química , Resinas Compostas/química , Materiais Dentários/química , Dentaduras , Nanopartículas , Poliestirenos , Zircônio , Dureza , Teste de Materiais , Metacrilatos , Microscopia Eletrônica de Varredura , Silanos , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Medicine (Baltimore) ; 98(40): e17385, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31577743

RESUMO

Although all-ceramic crowns have excellent biocompatibility and esthetic appearance, chipping may occur. The mechanical properties of monolithic zirconia restorative material are superior to those of all-ceramic restorative materials, and chipping caused by chewing hard foods could be avoided. This study aimed to evaluate the clinical efficacy of monolithic zirconia crowns for posterior teeth restorations.A total of 46 patients requiring posterior teeth restorations involving 49 teeth were treated with monolithic zirconia crown procedure. The treatment results were evaluated according to the modified California Dental Association criteria immediately after the procedure, and at 2, 24, 48, and 96 weeks after the procedure. The plaque index, gingival index, probing depth, crown marginal integrity, and attrition of the abutment teeth, antagonist teeth, corresponding contralateral teeth, and antagonist of the corresponding contralateral teeth were assessed. The patients were followed for up to 96 weeks.The marginal adaptation results of all 46 patients were evaluated as excellent, resulting in an excellent rate of 100%. Regarding the crown color match, only 3 cases (6.1%) were evaluated as acceptable. Marginal adaptation, anatomic form, crown margin integrity, color match, and gross fracture did not show significant differences compared with the different time points (P = .999). Surface texture at different time did not change significantly (P = .807). During the 96-week follow-up, 1 crack in the antagonist teeth was found in 1 patient. There were no significant differences in wear of the antagonist teeth at different time points (P = .972). The rate of "excellent" evaluation for crown restorations was 93.9% to 100%.The monolithic zirconia crown had no detectable adverse effects on the periodontal tissues, and the antagonist teeth attrition was small. Therefore, it has good potential in the clinical application of posterior teeth restorations in the short term.


Assuntos
Coroas , Materiais Dentários/química , Zircônio/química , Inquéritos de Saúde Bucal , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Feminino , Humanos , Masculino
8.
Biomed Mater Eng ; 30(4): 419-426, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31498119

RESUMO

BACKGROUND: The chemical properties of the oral environment have an appreciable influence on the in vivo degradation of CAD/CAM materials. OBJECTIVE: The aim of the present study was to investigate the effect of organic acids, heptane and ethanol (the food-simulating liquids) on CAD/CAM restorative materials. METHODS: Four CAD/CAM materials were selected: (1) 3M ESPE LAVA Ultimate, (2) VITA Enamic, (3) IPS e.max CAD, (4) VITA Suprinity. Seven different samples were fabricated in 15 × 4 × 1.2 mm dimensions from each material (n = 7, N = 140). The materials were conditioned for 7 days at 37 °C as follows: artificial saliva, 75% ethanol, heptane, 0.02 N citric acid, 0.02 N lactic acid in aqueous solution and were tested to obtain flexural strength, surface micro-hardness and wear characteristics. After conditioning, the flexural strength values were assessed using a universal testing machine (1 mm/min crosshead speed) and the fractured samples were used for determination of Vickers hardness values using a digital micro-hardness tester (100 g/10 s) and determination of wear using a chewing simulator. Two factor analysis of variance with interaction model and Tukey's post hoc test were used for statistical analysis. RESULTS: The highest mechanical property values were found for IPS e.max and VITA Suprinity and the lowest values were found for LAVA Ultimate. Organic acids negatively affected the mechanical properties of e.max CAD and Suprinity. Ethanol and heptane were more effective on LAVA Ultimate and Enamic. There were significant differences among groups (p < 0.05). CONCLUSION: The mechanical properties of CAD/CAM restorative materials are influenced by food-simulating liquids.


Assuntos
Cerâmica/química , Materiais Dentários/química , Materiais Biocompatíveis/química , Ácido Cítrico/química , Dureza , Humanos , Ácido Láctico/química , Teste de Materiais , Saliva/química , Estresse Mecânico , Propriedades de Superfície
9.
Mater Sci Eng C Mater Biol Appl ; 104: 109961, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500022

RESUMO

Formation of fungal biofilms on health care-related materials causes serious clinical consequences. This study reports a novel fungal repelling strategy to control fungal biofilm formation on denture biomaterials through layer-by-layer self-assembly (LBL). Amphiphilic quaternary ammonium chitosans (CS612) were synthesized and used as the antimicrobial positive layer, and sodium alginate (SA) was chosen as the negative layer to construct LBL multilayers on poly (methyl methacrylate) (PMMA)-based denture materials. The presence of LBL multilayers on denture disc was confirmed and characterized by surface zeta potential, water contact angle, AFM, and FT-IR analyses. The multilayer coatings, especially CS612 as the outmost layer, effectively prevented the fungal initial adhesion and biofilm formation. The Candida cells avoided the multilayer coatings and suspended in broth solution instead of forming biofilms, suggesting that the LBL multilayers had fungal repelling effects. The LBL multilayers were biocompatible toward mammalian cells. In stability tests, after immersion in PBS for 4 weeks under constant shaking and repeated brushing with a denture brush for up to 3000 times, the biofilm-controlling effects of the LBL multilayers were not affected, pointing to a novel long-term strategy in controlling fungal biofilms on denture and other related biomaterials.


Assuntos
Alginatos/química , Compostos de Amônio/química , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Quitosana/química , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Dentários/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Polimetil Metacrilato/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Propriedades de Superfície/efeitos dos fármacos
10.
Gen Dent ; 67(5): 30-34, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31454319

RESUMO

Digital dentistry has led to the success of same-day, single-crown delivery. Unlike traditional convection furnaces for fabrication of zirconia materials, which typically require several hours to complete sintering, a dedicated high-speed sintering furnace that reportedly sinters zirconia in minutes is now available. Sintering times may increase or decrease based on the size of the restoration due to a novel interface between the chairside acquisition unit, milling unit, and furnace. The purpose of this study was to compare the flexural properties (strength and modulus), optical parameters (translucency and opalescence), and grain size of a full-contour tetragonal zirconia material after sintering in either a novel high-speed furnace or a conventional zirconia furnace. Rectangular zirconia beams were milled and sintered using the high-speed induction furnace for 26.2 minutes or a conventional convection furnace for 4.3 hours. Flexural strength and modulus were determined by subjecting the beams to a 3-point bending test in a materials testing machine. Translucency and opalescence were calculated using a spectrophotometer, and grain size was determined by using an atomic force microscope. The dedicated high-speed induction furnace sintered the tetragonal zirconia specimens in substantially less time than the conventional convection furnace, with a statistically significant decrease in grain size and no significant difference in strength or optical properties.


Assuntos
Cerâmica , Materiais Dentários , Zircônio/química , Materiais Dentários/química , Teste de Materiais , Propriedades de Superfície
11.
Gen Dent ; 67(5): 72-76, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31454328

RESUMO

The objective of this study was to evaluate the influence of the radiopacity of composite resin restorations on the interpretation of phantom radiographic images and to correlate the diagnosis with clinical management. Eighty healthy extracted human third molars were divided into 4 groups (n = 20 each): 3 restorative groups and 1 group of untreated teeth. The radiopacity of the materials was evaluated objectively using 10-mm discs of the composite resins SureFil SDR Flow (SDR), Filtek Bulk Fill Flowable Restorative (Filtek Bulk), and Filtek Z250 XT (Z250). Standard Class II cavities were prepared in the teeth. In the SDR and Filtek Bulk groups, the respective material was placed as a 2-mm base, and the remainder of the cavity was restored with Z250. In the Z250 group, the entire preparation was filled with Z250 composite resin. Ten phantoms of 6 teeth each were created; each phantom included 1 molar selected randomly from each of the 4 groups and 2 healthy premolars. Bitewing radiographs of the phantoms were obtained with a digital phosphor plate system and stored. For the subjective analysis, 5 examiners evaluated each of the molars on the radiographs and established the diagnosis and treatment plan. The radiopacity of the materials was statistically similar (P = 0.413), and there was no statistically significant difference between groups in the interpretation of the images. The radiopacity of the materials met ISO standard 4049/2009. Diagnosis and decision-making were influenced by the radiopacity of the materials. Filtek Z250, which had the lowest radiopacity, was diagnosed correctly more often than SDR, which had higher radiopacity. Filtek Bulk had the highest opacity and the highest percentage of correct diagnoses. In clinical practice, radiographic visualization of restorations and dental structures is essential for establishing a correct diagnosis and treatment plan. A restorative material may be within the established requirements for radiopacity, but on radiographic evaluation it might not be differentiated from mineralized dental tissues.


Assuntos
Resinas Compostas , Cárie Dentária , Restauração Dentária Permanente , Radiografia Dentária Digital , Resinas Compostas/química , Materiais Dentários/química , Humanos , Teste de Materiais
12.
Photobiomodul Photomed Laser Surg ; 37(7): 434-441, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31265377

RESUMO

Objective: The purpose of this study is to investigate the effect of various presintering and sintered surface treatments and thermocycling on the bond strength between zirconia and veneer ceramics. Background data: Bond stability between zirconia and veneer ceramic is a major concern, and only limited evidence about its longevity is currently available. Moreover, no study has yet evaluated the influence of thermocycling on the bond strength of veneer ceramic to zirconia after Er,Cr:YSGG laser irradiation at different pulse durations and sandblasting. Materials and methods: In this study, 220 nonsintered zirconia specimens were prepared with CAD/CAM and randomly divided into 2 groups; half of the specimens in each group were stored in water for 1 week, and the other half were thermocycled (5000 cycles) between baths of 5°C and 55°C. Specimens were then divided into five subgroups based on the following surface treatments: control (untreated surface), sandblasting (120 µm Al2O3), and Er,Cr: YSGG laser irradiations (3 W-8 Hz, 3 W-15 Hz, and 3 W-20 Hz, MGG 6 laser tip, for 20 sec, distance of 10 mm, water/airflow of 55% and 65%). Morphological assessment was done using atomic force microscopy and scanning electron microscopy, and phase transformation was assessed by X-ray diffractometry. All specimens were then veneered with veneering ceramic, and bond strength test using a universal testing device at a 1 mm/min crosshead speed. Data were evaluated by Kruskal-Wallis variance analysis and the Mann-Whitney U test. Results: There was no significant difference in the bonding strength values among the (p > 0.05). Thermocycling reduced the bond strength, but it was not significant (p > 0.05), except for the presintering 20 Hz group (p < 0.02). Conclusions: Application of thermocycling to sintered zirconia specimens may be detrimental to the shear bond strength of zirconia ceramics. Treating the zirconia surface after sintering is not recommended, due to the decrease in bond strength.


Assuntos
Cerâmica/química , Colagem Dentária/métodos , Corrosão Dentária/métodos , Materiais Dentários/química , Lasers de Estado Sólido , Resistência ao Cisalhamento/efeitos da radiação , Zircônio/química , Desenho Assistido por Computador , Facetas Dentárias , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície
13.
Photobiomodul Photomed Laser Surg ; 37(7): 428-433, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31265378

RESUMO

Objective: Evaluate the bond strength of repairs made on composite resin following the treatment of the surface of the flaw with different bonding agents and/or CO2 laser. Background: The influence of CO2 laser and its interaction with other bonding agents on the surface of the flaw is not yet known. In this study, CO2 laser was chosen to treat the surface of the flaw due to its capacity to promote irregularities on the surface that enhance mechanical micro-retention. Methods: A block was created with Vitra APS nanohybrid composite resin (color: A3; FGM, Joinville, Brazil) measuring 5 mm in width, length, and depth (volume: 125 mm3). The surface of the flaw was treated before the repair with an adhesive, silane bonding agent, and/or CO2 laser. Six specimens were created in composite resin for each group (total: n = 36): G1: resin+resin; G2: adhesive+resin; G3: laser+adhesive; G4: laser+silane+adhesive; G5: silane+adhesive; G6: laser+silane. After the repair, the surfaces of the fracture of all specimens, which were submitted to the microtraction test, were analyzed under an optical microscope. Bond strength values obtained according to the type of surface treatment were tabulated and submitted to the Kruskal-Wallis test. Dunn's test was used to compare means. Results: G3 and G4 had significantly higher bond strength values compared to all other groups tested. Adhesive fractures predominated in all groups. However, G3 and G4 had a higher percentage of cohesive fractures compared to the other groups. Conclusions: The application of CO2 laser as a surface treatment led to greater bond strength of composite resin repairs in comparison with the groups that only received treatment with a burr and silanization. The groups submitted to CO2 laser also had a significantly lower number of adhesive failures when submitted to the microtraction test.


Assuntos
Resinas Compostas/química , Colagem Dentária , Esmalte Dentário/efeitos da radiação , Corrosão Dentária/métodos , Materiais Dentários/química , Lasers de Gás , Dióxido de Carbono , Análise do Estresse Dentário , Adesivos Dentinários/química , Teste de Materiais , Resistência ao Cisalhamento/efeitos da radiação , Estresse Mecânico , Propriedades de Superfície
14.
Biomed Res Int ; 2019: 8078230, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31058193

RESUMO

This in vitro study was designed to evaluate the effect of sol-gel derived TiO2 coating on blood coagulation, blood protein adsorption, and platelet response on zirconia surfaces. Square-shaped zirconia (n=96) (10x10x2 mm) was cut, ground, sintered, and finally cleansed ultrasonically in each of acetone and ethanol for 5 minutes. Three experimental groups (n=32) were fabricated: (a) zirconia coated with sol-gel derived TiO2, (b) zirconia coated with sol-gel derived TiO2 and treated with ultraviolet (UV) irradiation for 1 hour, and (c) non-coated zirconia as control. The coatings were prepared from tetraisopropyl orthotitanate solution by dip-coating. The thrombogenicity of the specimens was evaluated using a whole blood kinetic clotting time method where the extent of blood clotting was evaluated at 10, 20, 30, 40, 50, and 60 minutes (n=4/time point, total n=24/group). Scanning electron microscope images were taken to observe platelet morphologies after 1-hour incubation with platelet-rich plasma (PRP) (n=5/group). Surface characteristics were visualized using atomic force microscopy (n=1/group). Adsorption of plasma proteins and fibronectin on each surface was studied by gel electrophoresis (n=2/group). Significant differences were observed in blood coagulation between the test groups at 20-, 30-, 40-, and 50-minute time points (p<0.005). UV treated TiO2 coated specimens showed fastest blood coagulation followed by TiO2 coated and non-coated specimens. Furthermore, platelets appeared at a higher activation state on coated specimens. Gel electrophoresis revealed no difference in protein adsorption among the experimental groups. In summary, TiO2 coatings promoted blood coagulation, and it was further enhanced by UV treatment, which has the potential to hasten the wound healing process in vivo.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Materiais Dentários/química , Titânio/química , Zircônio/química , Plaquetas/efeitos dos fármacos , Plaquetas/ultraestrutura , Materiais Dentários/uso terapêutico , Humanos , Teste de Materiais , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Resistência ao Cisalhamento/efeitos dos fármacos , Titânio/uso terapêutico , Raios Ultravioleta , Zircônio/uso terapêutico
15.
ACS Appl Mater Interfaces ; 11(24): 21334-21342, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31134790

RESUMO

The rapid advancement of peptide- and amino-acid-based nanotechnology offers new approaches for the development of biomedical materials. The utilization of fluorenylmethyloxycarbonyl (Fmoc)-decorated self-assembling building blocks for antibacterial and anti-inflammatory purposes represents promising advancements in this field. Here, we present the antibacterial capabilities of the nanoassemblies formed by Fmoc-pentafluoro-l-phenylalanine-OH, their substantial effect on bacterial morphology, as well as new methods developed for the functional incorporation of these nanoassemblies within resin-based composites. These amalgamated materials inhibit and hinder bacterial growth and viability and are not cytotoxic toward mammalian cell lines. Importantly, due to the low dosage required to confer antibacterial activity, the integration of the nanoassemblies does not affect their mechanical and optical properties. This approach expands on the growing number of accounts on the intrinsic antibacterial capabilities of self-assembling building blocks and serves as a basis for further design and development of enhanced composite materials for biomedical applications.


Assuntos
Antibacterianos/química , Materiais Biocompatíveis/química , Nanoestruturas/química , Nanotecnologia/métodos , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Resinas Compostas/química , Materiais Dentários/química , Materiais Dentários/farmacologia
16.
Med Sci Monit ; 25: 3397-3405, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31066356

RESUMO

BACKGROUND While several tests can be used in the laboratory evaluation of composite resin-based cement materials, the push-out test remains the most prevalent. Due to difficulties in sample preparation, as well as a highly complex procedure, we attempted to develop an alternative method for testing the bond strength of dental resin cement materials. MATERIAL AND METHODS Ninety-six experimental samples of 2 dual-cure resin cements and 1 fiber post system were prepared for the 2 testing procedures: the push-out test and the modified Microbond test. The degree of monomer conversion was measured by Fourier-transform infrared spectroscopy. RESULTS The push-out test results indicated that the bond strength of dual-cure resin cement differs depending on the tooth root region to which it is applied (p<0.05), In addition, our findings show that Variolink II exhibits a much lower bond strength relative to RelyX ARC. These findings were confirmed by the modified Microbond test results. The monomer conversion rate results indicate average conversion rates of 85.81% and 61.35% for RelyX ARC and Variolnik II, respectively. CONCLUSIONS Our study confirms the practical utility of the modified Microbond test in the assessment of bond strength of dental cement resin-based materials. The proposed test method is particularly useful given that, relative to the push-out test, it requires a much smaller number of preparation and execution steps, thus reducing the potential for introducing errors, while increasing the reliability of the obtained findings.


Assuntos
Colagem Dentária/métodos , Cimentos Dentários/química , Cimentos de Resina/química , Adesivos , Bis-Fenol A-Glicidil Metacrilato , Resinas Compostas/química , Materiais Dentários/química , Porcelana Dentária , Cavidade Pulpar , Análise do Estresse Dentário , Dentina , Humanos , Teste de Materiais , Polietilenoglicóis , Ácidos Polimetacrílicos , Reprodutibilidade dos Testes , Resinas Sintéticas/química , Raiz Dentária
17.
Adv Colloid Interface Sci ; 269: 219-235, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31096075

RESUMO

This article focuses on the relevance of amorphous calcium (and magnesium) phosphates in living organisms. Although crystalline calcium phosphate (CaP)-based materials are known to constitute the major inorganic constituents of human hard tissues, amorphous CaP-based structures, often in combination with magnesium, are frequently employed by Nature to build up components of our body and guarantee their proper functioning. After a brief description of amorphous calcium phosphate (ACP) formation mechanism and structure, this paper is focused on the stabilization strategies that can be used to enhance the lifetime of the poorly stable amorphous phase. The various locations of our body in which ACP (pure or in combination with Mg2+) can be found (i.e. bone, enamel, small intestine, calciprotein particles and casein micelles) are highlighted, showing how the amorphous nature of ACP is often of paramount importance for the achievement of a specific physiological function. The last section is devoted to ACP-based biomaterials, focusing on how these materials differ from their crystalline counterparts in terms of biological response.


Assuntos
Fosfatos de Cálcio/metabolismo , Materiais Dentários/química , Compostos de Magnésio/metabolismo , Fosfatos/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Osso e Ossos/química , Osso e Ossos/metabolismo , Fosfatos de Cálcio/análise , Fosfatos de Cálcio/química , Caseínas/química , Esmalte Dentário/química , Esmalte Dentário/metabolismo , Humanos , Intestino Delgado/química , Intestino Delgado/metabolismo , Micelas , Leite Humano/química
18.
Biomed Mater Eng ; 30(3): 279-285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30988236

RESUMO

The objective of this study was to evaluate the effect of sodium hypochlorite and chlorhexidine solutions and their inactivating agents on the push-out bond strength of mineral trioxide aggregate (MTA). One hundred fifty root slices were prepared and their root canal spaces were enlarged using diamond burs. MTA was prepared and compacted to root canal spaces. The samples were randomly separated to 4 groups that would be immersed into the selected solutions (5.25% sodium hypochlorite (NaOCl), 5.25% NaOCl and sodium thiosulfate, 2% chlorhexidine (CHX), 2% CHX and a mixture of Tween 80 and 0.3% L-alfa-lecithin) and a control group (n = 30). Push-out bond strength of each specimen was tested with universal testing machine. The data was analyzed by one-way analysis of variance and Tukey tests. There were no significant differences between the push-out bond strength values of the irrigation groups and the control group. A significant difference was found between the push-out bond strength values of NaOCl-Sodium thiosulfate and CHX-L-alpha-lecithin groups. Contact with NaOCl and its neutralizing agent with MTA after 10 minutes of setting period increased the push-out bond strength of MTA. On the other hand, any contact with CHX alone or with subsequent application using L-alfa-lecithin should be avoided since that might decrease the push-out bond strength of freshly mixed MTA.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Clorexidina/química , Materiais Dentários/química , Óxidos/química , Irrigantes do Canal Radicular/química , Silicatos/química , Hipoclorito de Sódio/química , Análise do Estresse Dentário/instrumentação , Combinação de Medicamentos , Desenho de Equipamento , Humanos , Lecitinas/química , Teste de Materiais/instrumentação , Polissorbatos/química , Irrigação Terapêutica
19.
Microsc Res Tech ; 82(7): 1215-1223, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30938008

RESUMO

The aim of this study was to provide important insights into the effects of four different dental polishing protocols (one single-step and one multi-step either followed or not by diamond paste polishing) on the 3D surface morphology of two representative dental resin-based nanocomposites (a nanofilled and a nanohybrid composite) by means of digital image analysis and processing techniques. The 3D surface morphology was investigated by atomic force microscopy. Segmentation, statistics of height distributions (described by statistical parameters, according to ISO 25178-2: 2012) and Minkowski functionals were applied to the images to characterize the spatial patterns of analyzed samples at micrometer scale. The nanofilled composite had significantly lower values of height parameters in comparison with nanohybrid one. Multi-step polishing protocol generated a statistically significant smoother finish for both tested materials, than one-step polishing protocol, even when it was followed by diamond paste polishing. Diamond paste polishing generated a statistically significant smoother surface of tested samples. This suite of surface analysis tools is important in the research and manufacture of these dental resin-based nanocomposites, where material surfaces have a key role in the functionality of objects.


Assuntos
Polimento Dentário , Nanocompostos/química , Propriedades de Superfície , Resinas Compostas , Materiais Dentários/química , Diamante , Teste de Materiais , Microscopia Eletrônica de Varredura
20.
Comput Methods Biomech Biomed Engin ; 22(7): 706-712, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30931631

RESUMO

In implantology, when financial or biological feasibility limitations appear, it is necessary to use prostheses with geometries that deviate from the conventional, with a pontic in the absence of an intermediate implant. The aim of this study was analyze and understand the general differences in the stresses generated in implants, components and infrastructures according to the configuration of the prosthesis over three or two implants. Thus, this paper analyzes the von Mises equivalent stresses (VMES) of ductile materials on their external surfaces. The experimental groups: Regular Splinted Conventional Group (RCG), which had conventional infrastructures on 3 regular-length Morse taper implants (4x11 mm); Regular Splinted Pontic Group (RPG), which had infrastructures with intermediate pontics on 2 regular-length Morse taper implants (4x11 mm). The simulations of the groups were created with Ansys Workbench 10.0 software. The results revealed that the RPG presented greater areas of possible fragility due to higher stress concentrations, for example, in the cervical area of the union between the implant and component the top platform of the abutment, as well as greater coverage of the stress by the cervical implant threads. The RPG infrastructure was also more affected by stresses in the connection areas between the prostheses and on the occlusal surface. There is an advantage to using prostheses supported by a greater number of implants (RCG) because this decreases the stress in the analyzed structures and consequently improves stress dissipation to the supporting bone, which would preserve the system.


Assuntos
Implantes Dentários , Materiais Dentários/química , Planejamento de Prótese Dentária , Prótese Dentária Fixada por Implante , Análise do Estresse Dentário , Análise de Elementos Finitos , Estresse Mecânico , Prótese Parcial Fixa , Humanos , Processamento de Imagem Assistida por Computador
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