Comportamento de bases forradoras sob restaurações de composito

Orientador: Mario Fernando de GoesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A resistência flexural da dentina de um material restaurador (HERCULITE-XR), de bases forradoras (DYCAL, VIDRION F e FOS FATO DE ZINCO) e do conjunto formado pelo material restaurador/material de base foi verificada através de um Consistômetro com carga de 91 Kg/cm . Além disso, para os conjuntos formados pelo material restaurador/material de base, foi verificada a influência do carregamento axial de compressão na infiltração marginal, através de uma lupa esterioscópica Carl Zeiss, com aumento de 25 vezes. A análise dos resultados do ensaio de flexão demonstrou que, nas duas profundidades de cavidades estudadas, a dentina não apresentou diferença estatística significativa. Na espessura de base de 1 mm, o cimento DYCAL diferiu estatisticamente do cimento Vidrion F e ambos diferiram do cimento de Fosfato de Zinco. Para a espessura de base de 2 mm, os cimentos não apresentaram diferença estatística significante. Finalmente, os conjuntos formados pelo material restaurador/material de base não diferiram estatisticamente entre si. Os resultados do ensaio de infiltração marginal demonstraram que não houve diferença estatística significativa entre os corpos de prova que receberam ou não carregamento. A análise das fotografias, porém, revelou que, embora o corante tenha atingido o mesmo nível de penetração para os corpos de prova que receberam ou não carregamento, o volume de corante que penetrou nos corpos de prova que sofreram carregamento foi visivelmente maiorAbstract: The flexural strengths of human dentin, composite resin (Herculite-XR), base lining (Dycal, Vidrion F and Fosfato de Zinco), and combined of restoration material/base lining were determined by consistencymeter, with load of 91 kg/cm2. Besides, the influence of the compressive strenght in the microleakage was determined in the combined of restoration material/base lining by steroscopic magnifying glass Carl Zeiss. The results of dentin flexural test showed no significant difference between the two cavity depths studied. In the Dycal base thickness of 1 mm was significant for Vidrion F and both were significant for Fosfato de Zinco cements. For base thickness of 2 mm, the cements did not present significant differences. Finally, the combined formed by restoration material/base lining no presented significant differences.. The results of microleakage test did not show significant differences for the specimens that received of no compressive strength.However, the pictures showed that dye intered the same leveI for specimehs that received or no compressive strength. Forever, the volume of dye that infiltrated in specimens that received compressive strength was largerMestradoMateriais DentariosMestre em Ciência

Effect of surface treatments of laboratory-fabricated composites on the microtensile bond strength to a luting resin cement

The purpose of this study was to evaluate the influence of different surface treatments on composite resin on the microtensile bond strength to a luting resin cement. Two laboratory composites for indirect restorations, Solidex and Targis, and a conventional composite, Filtek Z250, were tested. Forty-eight composite resin blocks (5.0 x 5.0 x 5.0mm) were incrementally manufactured, which were randomly divided into six groups, according to the surface treatments: 1- control, 600-grit SiC paper (C); 2- silane priming (SI); 3- sandblasting with 50 mm Al2O3 for 10s (SA); 4- etching with 10% hydrofluoric acid for 60 s (HF); 5- HF + SI; 6 - SA + SI. Composite blocks submitted to similar surface treatments were bonded together with the resin adhesive Single Bond and Rely X luting composite. A 500-g load was applied for 5 minutes and the samples were light-cured for 40s. The bonded blocks were serially sectioned into 3 slabs with 0.9mm of thickness perpendicularly to the bonded interface (n = 12). Slabs were trimmed to a dumbbell shape and tested in tension at 0.5mm/min. For all composites tested, the application of a silane primer after sandblasting provided the highest bond strength means.O objetivo deste estudo foi avaliar a influência de diferentes tratamentos de superfície na resistência de união de resinas compostas a um agente de fixação resinoso. Dois compósitos de laboratório, Solidex e Targis, e um compósito convencional, Filtek Z250, foram testados. Quarenta e oito blocos de resina composta (5.0 x 5.0 x 5.0mm) foram confeccionados através da técnica incremental, para cada compósito testado, e foram aleatoriamente divididos em 6 grupos. Os blocos foram submetidos a seis tratamentos de superfície: 1 - Controle, Lixa 600-SiC (C); 2 - Silanização (SI); 3 - Jateamento com Al2O3 50µm por 10 segundos (SA); 4 - Condicionamento com ácido fluorídrico por 60 segundos (HF); 5 - HF + SI; 6 - SA + SI. Blocos submetidos ao mesmo tratamento foram unidos com o agente de fixação resinoso Rely X. Uma carga de 500g foi aplicada por 5 minutos e as amostras foram fotoativadas por 40 segundos. Os blocos unidos foram seccionados em fatias de 0.9mm de espessura perpendicularmente à interface de união (n = 12). Foram realizadas constrições limitando a interface de união a 1mm e as amostras foram levadas para o ensaio de tração. As maiores médias de união foram obtidas para as amostras submetidas à aplicação do silano após o jateamento com Al2O3

Lithium disilicate ceramic fragments in maxillary midline diastema / Fragmentos cerâmicos à base de dissilicato de lítio em diastema da linha média maxilar

Maxillary midline diastema is one of the main smile esthetic complaints by the population. Considering the positive effect that an esthetically harmonious smile can produce, in the view of conservative adhesive dentistry, ceramic fragments have been highly requested as a resolutive therapeutic option in cases of closure of the maxillary midline diastema. Therefore, this study presents a clinical case report in which ceramic fragments based on high-translucency (HT) lithium disilicate were used in units 11 and 21 to close the midline diastema in a young adult patient. Before the restorative procedure, a study model, diagnostic wax-up for the mock-up and provisional pieces were produced. After a conservative tooth preparation, the teeth and ceramic fragments were conditioned following pre-established protocols, and a photoactivated resin cement was used as a cementing agent. The ceramic fragments met the expectations of patients and were indicated for being a conservative, safe, and effective esthetic treatment. 

Effect of light curing modes and ethanol immersion media on the susceptibility of a microhybrid composite resin to staining

The aim of this in vitro study was to evaluate the susceptibility of a hybrid composite resin (Filtek Z250 - 3M ESPE) to staining, when light cured in four different modes and immersed in two different media. Composite resin specimens were randomly prepared and polymerized according to the experimental groups (conventional - 550 mW/cm² / 30 seconds; soft start - 300mW/cm² / 10 seconds + 550 mW/cm² / 20 seconds; high intensity - 1060 mW/cm² - 10 seconds; pulse delay - 550 mW/cm² - 1 seconds + 60 seconds of waiting time + 550 mW/cm² - 20 seconds) and immersed in one of two media (distilled water or absolute ethanol) for 24h. Next, the specimens were immersed in a 2% methylene blue solution for 12 hours. Afterwards, the specimens were washed and prepared for the spectrophotometric analysis. For statistical analysis, two-way ANOVA (4X2) and Tukey's test were performed on the data at 0.05 confidence level. Soft start showed the least staining, and was statistically different from the high intensity and pulse delay light curing modes (p;0.05). There were no significant differences between the two immersion media (p>;0.05). The soft start polymerization mode showed lower susceptibly of the composite resin to staining than high intensity and pulse delay, irrespective of the immersion medium

Desensitizing Agent Previously Applied During In-Office Bleaching: A Double-Blind Randomized Clinical Trial

Objective: To compare the clinical effect of two desensitizing agents used before the application of a bleaching gel based on 35% hydrogen peroxide (HP). Material and Methods: 30 patients were selected, and two desensitizing agents with different mechanisms of action were applied: Fluorine Neutral 2% (FN), which acts by blocking dentinal canaliculi while Potassium Nitrate 5% with 2% Sodium Fluoride (PN/SF) that acts in nerve transmission and blockade. Desensitizers were used before the application of 35% HP. For whitening, three clinical sessions were performed, with an interval of seven days, with three applications of the bleaching gel for 15 minutes, totaling 45 minutes/session. Tooth sensitivity (TS) was assessed with the numerical analog scale, and a spectrophotometer was used to obtain the color variation (ΔE).ΔE were submitted to ANOVA and Tukey test (p<0.05), and TS data were submitted to a two-way ANOVA analysis. Results: For sensitivity experience, the Tukey test indicated differences between PN/SF and the placebo I, but there was no statistically significant difference between FN and the placebo II. The TS was lower when the desensitizing gel was used during the bleaching procedure compared to after treatment, regardless of the desensitizing agents. Conclusion: PN/SF before in-office tooth bleaching can reduce TS intensity, and the use of desensitizing gel before bleaching did not affect the bleaching efficacy

Ação de dentifrício na redução da sensibilidade associada ao clareamento dental caseiro: estudo clínico piloto / Toothpaste action in reducing sensitivity associated with home tooth whitening: pilot clinical study

Objetivo: Avaliar, clinicamente, a ação do dentifrício REGENERATE TM Emanel Science na redução da dor e variação de cor causadas pela técnica de clareamento dental caseiro por meio de um estudo clínico duplo cego controlado. Materiais e Métodos: foram selecionados 24 voluntários para serem submetidos ao clareamento dental caseiro em 4 sessões clínicas com intervalo de uma semana, usando gel clareador (peróxido de carbamida - 16%). Na manhã seguinte de cada sessão de clareamento, os voluntários usaram uma moldeira personalizada por 4 horas contendo um dos dentifrícios em relação aos grupos experimentais: (1) Sucralose (S) (Controle); (2) Fosfato de Sódio (FS) e Silicato de Cálcio (SC) - Tecnologia NR-5 (Tratamento). A dor foi avaliada antes do uso da moldeira com dentifrício (S1, S3, S5 e S7) e após (S2, S4, S6 e S8) por 4 semanas utilizando a escala numérica analógica com escores de 0 a 10. Para variação de cor (ΔE), foi utilizado um espectrofotômetro (Easyshade). Resultados: o grupo de tratamento (Tecnologia NR-5) apresentou redução da dor em relação ao grupo controle (p 0,05). Houve uma redução da dor após o uso do dentifrício na moldeira personalizada por 4 horas (S2, S4, S6 e S8) e não houve diferença de ΔE entre os grupos experimentais após o tratamento clareador (p = 0,918). Conclusão: o uso de dentifrício dessensibilizante com FS e SC (Technology NR-5) em moldeira plástica personalizada se mostrou uma opção de tratamento viável e eficiente para redução da dor causada pelo clareamento dental caseiro e o uso de dentifrício dessensibilizante não influenciou a eficácia do tratamento clareador, em relação à alteração de cor

Effects of desensitizing products on the reduction of pain sensitivity caused by in-office tooth bleaching: a 24-week follow-up

Objective: To clinically assess the effect of desensitizing gels and dentifrices on the reduction in pain sensitivity and color variation during tooth bleaching. Methodology: A total of 108 volunteers were randomly separated into the following groups of n=12: GT/S-glycerine and thickener/sucralose; NF/S-potassium nitrate and sodium fluoride/sucralose; NA/S-potassium nitrate and arginine/sucralose; GT/AC-glycerine and thickener/arginine and calcium carbonate; NF/AC-potassium nitrate and sodium fluoride/arginine and calcium carbonate; NA/AC-potassium nitrate and arginine/arginine and calcium carbonate; GT/PN-glycerine and thickener/potassium nitrate; NF/PN-potassium nitrate and sodium fluoride/potassium nitrate; and NA/PN-potassium nitrate and arginine/potassium nitrate. Sensitivity was assessed with the numerical analogue scale, and color variation (ΔE) was measured with a spectrophotometer. The sensitivity values obtained were subjected to a multivariate analysis of variance (MANOVA) and color variation values were subjected to a randomized analysis of variance (p<0.05). Results: The NF/AC, NA/AC, NF/PN, and NA/PN groups presented lower sensitivity values and reduced sensitivity compared to those of the other groups throughout the clinical sessions. None of the groups showed sensitivity at the 24-week assessment. Statistically, no significant difference were observed in the color values among the groups four weeks after the beginning of bleaching (p=0.074). Additionally, the color assessment of all groups was statistically similar four weeks (p=0.084) and 24 weeks (p=0.118) after the beginning. Conclusion: Our results indicate that adding NF/S, NA/S, NF/AC, and NA/AC desensitizers to tooth bleaching protocols reduces pain sensitivity without affecting its effectiveness

The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements

The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37A degrees C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p a parts per thousand currency signaEuro parts per thousand 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.CAPE

Analysis of self-etch adhesives behavior in class I composite restorations with different treatment of enamel margins and light-activation sources/ Análise do comportamento de adesivos autocondicionantes em restaurações de resina composta classe I com diferentes tratamentos das margens de esmalte e fontes de ativação de luz

Objective: To evaluate the microtensile bond strength (MTBS), knoop microhardness (KHN) and gap formation of class I restorations restored with self-etching adhesives and resin composites light-activated by either halogen or LED light curing units. Materials and Methods: Class I cavities were prepared in one hundred and forty-four human third molars. Three self-etching adhesives (Clearfil S3 Bond - S3, Clearfil Protect Bond – ProtectB and One-Up Bond F Plus - OneUp) were applied to the cavities, which had the enamel margins either etched with 35% phosphoric acid or left unecthed. The cavities were incrementally restored with TPH3 restorative composite, which was light-activated using Light Emitted by Diode (Hadii-Cal) or Halogen Lamp (Optilux 501). Epoxy resin replicas were obtained from the restored teeth, which were then submitted to thermal cycling. Afterwards, new replicas were obtained and the gaps at the resin composite/enamel margin interface were analyzed by Scanning Electronic Microscopy. Half sample was randomly tested for microtensile bond strength test (n=6) while the other half had the composite tested for KHN (n=6). Results: The etched enamel contributed to avoid gap formation only when OneUp adhesive system was used. No significant difference in MTBS values was found among groups. For KHN analysis, all restorations light-activated with LED showed higher KHN values than those light-activated with halogen lamps. In addition, the resin composites used to restore cavities with acid etched enamel margins showed higher KHN means than those used in cavities having unteched enamel margins. Conclusion: The resin composite bonded to cavities with S3 showed the lowest KHN values at the intermediate and bottom. ProtectB showed no significant differences for the different surface depths

Effects of residual contamination on mechanical properties and real-time conversion of etch-and-rinse adhesive / Efeitos da contaminação residual nas propriedades mecânicas e na cinética de conversão de adesivos convencionais

Introduction: An ideal hybrid layer should have water and solvents completely replaced by resin monomers, thus creating an interdiffusion zone with collagen and resin, and guaranteeing resistance and adequate mechanical properties to resist the challenges incurred in restoration. Objective: To evaluate the influence of residual contamination by different concentrations of water, ethanol and chlorexidine on mechanical properties and conversion of two etch-and-rinse adhesives. Method: Bar specimens of a model adhesive (M1) and a commercial Scotchbond MP adhesive (SBMP) were prepared and submitted to flexural strength (FS), elastic modulus (E), conversion degree (DC) and the kinetics of cure (K) evaluation. The real-time polymerization (RP) was monitored for 120 seconds. The data were statistically analyzed by two-way ANOVA and Tukey ?s test (?=0.05). Results: All solutions showed a decrease in FS and E values. For M1 adhesive, this decrease could be noted with increase of all dilutions tested. A decrease in DC values also was noted as dilutions increased, independent of solution tested. For SBMP adhesive, the mechanical properties were affected more by water and chlorexidine solutions and, it was noted an increase in DC with the increase of solution, especially for ethanol. For K test, adding water to adhesives, a progressive decrease could be noted on graphics. Conclusions: So a reduction in mechanical properties of adhesive solutions could be noted when extreme amounts of residual solutions. Nevertheless, at lowest concentrations, ethanol and chlorexidine seems not interfere on K and RP of adhesives.