Giselle Maria Marchi Baron

Bio: Giselle Maria Marchi Baron is an academic researcher from State University of Campinas. The author has contributed to research in topics: Ceramic & Bond strength. The author has an hindex of 1, co-authored 6 publications receiving 9 citations.

Caracteristicas da união a ceramica de zirconia tetragonal policristalina contendo itrio

Abstract: Cerâmicas de zirconia tetragonal policristalina contendo itrio (Y-TZP) apresentam propriedades mecânicas superiores as das demais cerâmicas odontologicas. No entanto, a tecnica de cimentacao mais adequada a estes materiais ainda nao foi determinada. Os objetivos deste estudo foram: 1) Revisar a literatura a respeito de cerâmicas Y-TZP e seu uso em odontologia; 2) Avaliar o efeito de diferentes intensidades de energia do laser de Er:YAG e do jateamento com particulas de Al2O3 na rugosidade superficial e nas caracteristicas morfologicas de cerâmicas Y-TZP e 3) Investigar a influencia de diferentes tratamentos de superficie e primers para metal na resistencia de uniao de dois cimentos resinosos a cerâmica Y-TZP. A analise da rugosidade superficial e das caracteristicas morfologicas foi realizada em duas cerâmicas Y-TZP: Cercon Smart Ceramics e Procera Zirconia. Trinta placas de cada cerâmica foram separadas em cinco grupos experimentais de acordo com o tratamento de superficie recebido [nenhum tratamento (Controle), jateamento com particulas de Al2O3 ou irradiacao com laser de Er:YAG em diferentes intensidades de energia (200mJ, 400mJ ou 600mJ)]. Apos o respectivo tratamento superficial, as placas foram cobertas com ouro e a rugosidade superficial media (Ra, mm) foi mensurada em microscopia confocal. Caracteristicas morfologicas das superficies foramobservadas em microscopia optica e eletronica de varredura. Os resultados demonstraram que a irradiacao com laser nas intensidades de 400mJ e 600mJ promoveu aumento acentuado da rugosidade superficial, alem da formacao de fendas, perda de massa e alteracao de cor. A irradiacao com 200mJ de intensidade e o jateamento com particulas de Al2O3 resultaram em alteracoes superficiais menos agressivas que as altas intensidades do laser. Para a analise da resistencia de uniao, 240 placas de cerâmica (Cercon SmartCeramics) e 240 fragmentos de dentina com extremidade recortada em formato cilindrico (0,8mm de diâmetro) foram distribuidos em 24 grupos (n=10) de acordo com a combinacao entre tratamento de superficie (nenhum, jateamento com particulas de Al2O3 ou irradiacao com laser de Er:YAG utilizando 200mJ como intensidade de energia), primer para metal (nenhum, Alloy Primer, Metal Primer II ou Metaltite) e cimento resinoso (Panavia F2.0 ou Calibra). Fragmentos de dentina foram cimentados nas placas de cerâmica, os corpos- eprova foram fixados ao aparato de microcisalhamento e o ensaio foi realizado com velocidade de 1mm/min ate a fratura. O jateamento com particulas de Al2O3 resultou em maior resistencia de uniao para ambos os cimentos resinosos. Comparado ao Panavia F2.0, o cimento Calibra apresentou maior resistencia de uniao nos grupos jateados e irradiados. Os dois cimentos demonstraram comportamento semelhante nos grupos sem tratamento de superficie. Os tres primers para metal apresentaram resultados semelhantes entre si, independentemente do tratamento da superficie e do cimento resinoso, e a resistencia de uniao da interface cerâmica-dente aumentou com a sua utilizacao. Pode-se concluir que, apesar da irradiacao com 200mJ de intensidade promover alteracoes superficiais na cerâmica Y-TZP, apenas associacao do jateamento com particulas de Al2O3 com a aplicacao de primers para metal constitui numa tecnica efetiva para uniao de cimentos resinosos a estas cerâmicas Abstract

Light curing resin cements containing iodonium salts promote suitable apical bonding of posts to radicular dentin.

Abstract: The aim of this study was to analyze the efficiency of experimental light-curing resin cements (ERCs) with a ternary photo-initiator system containing diphenyliodonium hexafluorphosphate (DPI) and different amines on retention of glass-fiber posts to dentin (GFP). ERCs formulations: a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenylpropane and triethyleneglycol dimethacrylate. Camphorquinone was used as initiator. Six experimental groups were established according to the amine used: [ethyl-4-(dimethylamino)benzoate-EDMAB or 2-(dimethylamino)ethyl methacrylate-DMAEMA] and the concentration of DPI (0, 0.5 mol%, 1 mol%). The resin cements Variolink II (dual- and light-cured versions) were used as commercial reference. Eighty recently extracted bovine incisors (n = 10) were selected for this study. The roots were prepared and the fiber posts were cemented with the resin cement specified for each experimental group. Specimens from coronal, middle, and apical thirds of the root were subjected to push-out bond strength test 24 hours after bonding. Data were subjected to split-plot ANOVA and the Tukey test (p = 0.05). ERCs containing DPI showed statistically significant higher bond strengths compared with ERCs without DPI. ERCs containing DPI were statistically similar to VARIOLINK II – dual-cured and superior to VARIOLINK II – light-cured (except for EDMAB – 1DPI in the medium third and DMAEMA – 1DPI in the coronal third). Different amines did not influence post retention. The apical root region showed the lowest bond strength for the groups EDAB-0DPI, DMAEMA-0DPI and VARIOLINK II light-cured. Light-cured ERCs containing DPI were efficient for GFP retention to radicular dentin, with similar behaviour to that of dual-curing commercial resin cement.

Influence of a hydrophobic monomer on the physical and mechanical properties of experimental surface sealants.

Abstract: This study evaluated the effect of adding the hydrophobic monomer 1,12 dodecanediol dimethacrylate (DDDMA) to experimental sealants with and without thermocycling on degree of conversion (DC), water sorption (WS), water solubility (WSB), color stability (ΔE), and micro-shear bond strength (μSBS). Five experimental and one commercially available sealant (Bisco - BIS) were tested. The experimental sealants were formulated by mixing different percentages of DDDMA monomers and urethane dimethacrylate (UDMA). The photoinitiator system was composed by camphorquinone (CQ) and tertiary amine 4-ethyl benzoate dimetilamiono (EDBA). Ethanol was used as a solvent. The experimental groups were named sequentially according to the monomeric content (DDDMA/UDMA): S40/40 (40/40), S50/30 (50/30), S60/20 (60/20), S70/10 (70/10) and S80/0 (80/0). Data were analyzed separately by one-way ANOVA, followed by Tukey's test (p<0.05). The values of DC ranged from 94.59% (S40/40) to 54.02% (S80/10). BIS showed the highest WS value (p<0.05) and S40/40, S50/30, S60/20 and S80/0 showed the lowest WS values of all tested sealants. WSB values ranged from 7.88 µg/mm3 (BIS) to 13.27 µg/mm3 (S70/10). The highest ΔE value was 11.05±2.88 for BIS and the highest μSBS value was found for S60/20. No significant difference was observed in bond strength between sealants and bovine enamel after thermocycling. Adding DDDMA to the composition of surface sealants can improve its performance, once the monomer increased the degree of conversion and the color stability.

Evaluation of surface roughness of resin-based composites submitted to different light-activation protocols and bleaching agents

Abstract: This study evaluated the surface roughness (Ra) of methacrylate and silorane-based composites submitted to different light-activation protocols and bleaching agents. The samples were divided into 12 groups (n=10) according to the composite (Filtek Z250 - 3M Espe, Filtek P90 - 3M Espe and Opallis - FGM); to the light-activation protocol (1000 mW/cm 2 X 18 s (S) and 3200 mW/cm 2 X 6 seconds (PE)); and bleaching agent (hydrogen peroxide at 6% and hydrogen peroxide at 35%). Roughness test were carried out at the following set times: initial (R1), after polishing (R2) and 24 hours after bleaching (R3). Data obtained were submitted to the statistical analysis. The results showed that higher values of Ra in R1 were obtained by Filtek P90 composite, differing significantly of the other samples, which showed similar results among them. There was significant decrease of Ra in R2 under all the conditions, except by the Opallis composite, independently on the light-activation protocol, and Filtek Z250 light-activated by PE protocol. There were no difference between R2 and R3 for all the composites and any light-activation protocol. It was possible conclude that bleaching agents did not interfere in significant way on surface roughness of the composite evaluated.

Influence of Surface Treatments and Adhesive Systems on Lithium Disilicate Microshear Bond Strength

Abstract: The purpose of this study was to evaluate the microshear bond strength of ceramic prosthetic structures reinforced by lithium disilicate cemented with resin cement under conditions of different surface treatments and adhesive systems. Seventy-two rectangular blocks of lithium disilicate (6.5 mm long × 5 mm wide × 1 mm thick) were fabricated, air abraded with 50-μm Al2O3 particles and divided into six groups (n=12) depending on the surface pretreatments. The groups were as follows: 10HF/S/SBM: 10% hydrofluoric acid etched for 20 s (10HF) + silane (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM and S/SB. Two 1-mm-long plastic tubes were placed on the specimens, filled with RelyX ARC resin cement and cured for 20 s per tube. The plastic tube was removed, and the microshear bond strength was tested. Data were submitted to analysis of variance and Tukey's tests (α=0.05). Fractured specimens were observed under optical microscopy. For both adhesives, the bond strengths (MPa) of groups treated with acid-etching and silane (10HF/S/SB: 24.82, 10HF/S/SBM: 24.90) were higher (p<0.001) than those of groups treated with acid-etching (10HF/SB: 16.47, 10HF/SBM: 19.94) only or only silane (S/SB: 18.42, S/SBM: 13.24). All groups showed a predominance of failure adhesive. The silanization should be a clinical step in cementing ceramic structures reinforced by lithium disilicate, even with the application of universal adhesive that contains silane in its formulation.

Solvent and HEMA Increase Adhesive Toxicity and Cytokine Release from Dental Pulp Cells

Abstract: The aim of the present study was to evaluate the effect of the hydroxyethyl-methacrylate (HEMA) concentration and solvent content of dental adhesives on cell viability and cytokine (IL-1b, IL-6, IL-10, TNF-α) release by human dental pulp cells (HDPCs). HDPCs were obtained from fresh extracted human third molars. Experimental adhesives were prepared containing different concentrations of HEMA (0%, 10%, and 20%) with and without solvent (ethanol 10%). Cylindrical specimens were immersed on culture medium during 24 h to obtain the extracts. The cells were incubated with extracts (culture medium + components leached from the adhesives) of different adhesives, and cell viability and cytokine release were evaluated after 6 and 24 h of exposure. Adhesives containing HEMA promoted high cell viability reduction after 6 h of exposure; but after 24 h, the results were similar to the ones found among control group cells. These effects on cell viability were prominently increased with the addition of solvent. Although IL-1b release was not affected by exposure to eluates, other cytokines (IL-10, IL-6, TNF-α) were modulated by the different experiment conditions, directly influenced by the HEMA concentration and presence of solvent. Higher HEMA concentrations, combined with the presence of solvent, can promote significant reduction on HDPC viability, increasing the release of anti- and pro-inflammatory mediators.

Strain determination of self-adhesive resin cement using 3D digital image correlation method

Abstract: Aleksandra D. Mitrović1, Ivan V. Tanasić2, Nenad R. Mitrović1, Miloš S. Milošević3, Ljiljana Đ. Tihaček-Šojić2, Dušan G. Antonović4 1University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia; 2University of Belgrade, School of Dental Medicine, Belgrade, Serbia; 3University of Belgrade, Faculty of Mechanical Engineering, Innovation Center, Belgrade, Serbia; 4University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia

Shear Bond Strength of Lithium Disilicate to Resin Cement After Treatment with Hydrofluoric Acid and a Self-etching Ceramic Primer

Abstract: The aim of this work was to analyze the properties and shear bond strength (SBS) of lithium disilicate to resin cement before and after etching the glass-ceramic surfaces. Lithium-metasilicate samples were heat treated and characterized by Scanning Electron Microscopy, X-ray diffraction and roughness measurement. For the analysis of the shear bonding strength (SBS) of lithium disilicate to dental resin cement, three groups (n = 12) of Li2Si2O5 were prepared: 1°)without treatment (NT); 2°)surface etching with hydrofluoric acid(HF), followed by silane agent and adhesive treatment; 3°) surface treatment with a self-etching ceramic primer (SECP). After the heat-treatment, the samples had Li2Si2O5 crystalline phase dispersed in a residual amorphous phase. Roughness of the NT and SECP samples was smaller that of the HF samples. Samples without surface treatment (NT) had the lowest SBS (5.5MPa). HF(24.2MPa) and SECP(24.8MPa) samples has similar SBS. Weibull statistics showed that HF-samples are more reliable than NT and SECP. The SBS was significantly increased by either HF etching and SECP surface treatment. While the chemical characteristics of the surface submitted to SECP treatment are considered to be responsible for the SBS increase, the main adhesion mechanism after HF etching is the increase in surface roughness.

Facetas Cerâmicas Estéticas Associadas a Próteses Metalocerâmicas: Relato de Caso

Abstract: Facetas cerâmicas fornecem resultados esteticos satisfatorios, preservando a estrutura dentaria. A cerâmica dental pode melhorar a aparencia estetica e restabelecer a resistencia e a funcao dos dentes. Nos dentes anteriores restaurados, as superficies funcionais, por exemplo, em orientacao anterior e lateral podem ser restauradas efetivamente. As caracteristicas da cerâmica dental, como a estabilidade da cor e as propriedades mecânicas e opticas, tornam este material uma boa escolha para restauracoes indiretas, especialmente, quando sao necessarias funcoes otimas e a estetica. Alem disso, o dissilicato de litio e uma cerâmica dental, que imita a estetica e a resistencia da estrutura dentaria natural e foi utilizado no presente relato de caso clinico.Palavras-chave: Protese Dentaria. Estetica Dentaria. Cerâmica.AbstractCeramic veneers provide satisfactory esthetic outcomes while preserving the dental structure. Dental ceramics can both improve the esthetic appearance and reestablish the teeth’s strength and function. In restored anterior teeth, functional surfaces, for example, anterior and lateral guidance, can be restored effectively. The characteristics of dental ceramics, such as color stability and mechanical and optical properties, make this material a good choice for indirect restorations, especially when optimum function and esthetics are required. Moreover, lithium disilicate is a dental ceramic that mimics the esthetics and strength of the natural tooth structure and it was used in the present clinical case report.Keywords: Dental Prosthesis. Esthetics, Dental. Ceramics.