Abstract This double-blind randomized controlled clinical trial evaluated the effectiveness of dentin pretreatment with 100% ethanol (EWBT – ethanol wet bonding technique) and different adhesive protocols in noncarious cervical lesions (NCCL) after 6 months. Patients presenting at least one NCCL were included. NCCLs (n=148) were randomly assigned to 4 groups: NE (Non-EWBT + three-step etch-and-rinse (Scotchbond Multi Purpose, 3M ESPE [MP]), E (EWBT + MP); EB (EWBT + [Bond – third step of MP]), and EU (EWBT + universal adhesive (Single Bond Universal, 3M ESPE). Conventional acid-etching (Condac 37%, FGM) and nanohybrid resin composite (Z350, 3M ESPE) were used. Trained and calibrated examiners (Kappa = 0.61) evaluated the restorations at baseline (7 days) and 6-month recall using the USPHS modified criteria. Data were subjected to Chi square (α = 0.05). Differences in the success rate were found for the treatments (p = 0.003). EB presented the lowest success rate compared with the other groups (p < 0.02). No significant differences were detected among NE, E, and EU (p > 0.49). The survival rates were 97.23%, 97.30%, 78.95%, and 97.30% for NE, E, EB, and EU, respectively. Regarding postoperative sensitivity, a significant reduction was found for groups E (p = 0.027) and EU (p < 0.01) after 6 months. After 6 months, EWBT associated to the hydrophobic adhesive system had the highest failure rate.

ABSTRACT This study evaluated the effect of different artificial aging on fluorescence of resin composites. Forty-five cylindrical specimens (6mm in diameter and 1mm thick) were made of each resin composite: IPS Empress Direct, Filtek™ Z350 XT, and Durafill. A baseline measurement of fluorescence by the direct method using the fluorescence spectrophotometer RF-5301 PC was performed. After, resin specimens were divided into 3 groups according to artificial aging protocol to be submitted: (1) aging by mechanical brushing: 30,000 cycles were performed, with fluorescence measurements after 10,000, 20,000 and 30,000 cycles; (2) chemical aging by ethanol: the samples were immersed in ethanol for 15 days, with measurements after 5, 10 and 15 days of immersion; (3) light aging: resin specimens were subjected to UV radiation for 216h with fluorescence readings after 72, 144, 216h. Data were submitted to one-way repeated measures ANOVA and Tukey’s test (α=0.05). Baseline fluorescence of the tested resins was ranked in this ascending order: Durafill < Filtek Z350 XT < IPS Empress Direct. Simulated toothbrushing and ethanol immersion reduced fluorescence, except for Z350 XT. For light exposition, fluorescence was reduced after 100h for Empress Direct and Durafill, while a reduction after 100h and 200h was detected for Z350 XT. Artificial aging protocols influenced the fluorescence and that this phenomenon is material dependent. In general, the fluorescence is reduced with aging.

Resumo: O objetivo deste estudo foi avaliar o efeito do clareamento com peróxido de hidrogênio na fluorescência e cor do esmalte e da dentina bovina. Vinte e cinco discos de dentina e 25 discos de esmalte, com 6 mm de diâmetro e 1 mm de espessura, foram obtidos. A fluorescência direta (Espectrofluorometria) e cor (espectrofotometria) foram avaliados. Depois da leitura inicial de cor e fluorescência, os espécimes foram imersos em solução de peróxido de hidrogénio a 35% (HP) durante 1 h. Este procedimento foi repetido após 7 dias. E as medições de fluorescência e de cor finais foram realizados após a segunda imersão. A caracterização química de 5 espécimes adicionais também foi realizada. Os dados foram submetidos à ANOVA de medidas repetidas e teste de Tukey para a fluorescência Teste e teste t não pareado para a cor e os componentes químicos (p<0,05). A fluorescência diminuiu significativamente nos espécimes de dentina após o clareamento. O esmalte apresentou fluorescência mais baixa do que a dentina na leitura inicial, mas esse parâmetro não diminuiu após o clareamento. Foram observadas alterações de cor para ambos os substratos, com significativamente maior efeito de clareamento em dentina (AE=10,37) (p<0,001). O clareamento com peróxido de hidrogênio provocou diminuição significativa na fluorescência da dentina e promoveu alterações de cor significativas na dentina e esmalte com resultados mais pronunciados em dentina.

Abstract: The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed in a 35% hydrogen peroxide (HP) solution for 1 h. This procedure was repeated after 7 days. Final fluorescence and color measurements were performed after the second immersion. Chemical characterization of 5 additional specimens was also performed. Data were submitted to repeated analysis of variance and Tukey´s test for fluorescence and unpaired t-test for color and chemical components (p<0.05). Fluorescence decreased significantly in dentin specimens after whitening. Enamel presented lower fluorescence than dentin at baseline, but this parameter did not decrease after whitening. Color changes were observed for both substrates, with significantly greater whitening effect in dentin (ΔE=10.37) (p<0.001). Whitening by hydrogen peroxide induced significant decrease in fluorescence of tooth dentin and promoted significant color changes in dentin and enamel with more accentuated outcomes in dentin.

O objetivo deste estudo foi investigar os efeitos de algumas bebidas ácidas sobre a erosão da dentina, utilizando métodos de análise de perfil de superfície (SP) e espectrometria de energia dispersiva de fluorescência de raios X (EDXRF). Cem blocos de dentina padronizados obtidos de raízes de incisivos bovinos foram utilizados. Os blocos de dentina medindo 5x5 mm foram planificados, polidos e metade de cada superfície das amostras foram impermeabilizados com esmalte para unhas. Por 60 min, as superfícies de dentina foram imersas em 50 mL de 5 bebidas diferentes (Gatorade, suco de laranja, Coca-Cola, Red Bull e vinho branco), 20 blocos em cada bebida. O pH de cada bebida foi medido. Após o desafio erosivo, o esmalte de unha foi removido e SP foram analisados. A concentração de minerais das superfícies de dentina foi determinada por meio de EDXRF. Os dados foram analisados estatisticamente por ANOVA e teste de Tukey. (p<0,05). A análise SP mostrou que o Red-Bull apresentou o maior potencial erosivo. Os resultados do EDXRF apresentaram uma diminuição do fosfato dos grupos imersos no Red-Bull, suco de laranja e vinho branco, e não houve diferença significativa no teor de cálcio entre a superfície de referência e a superfície que sofreu erosão. O Red Bull apresentou o maior potencial erosivo sobre a dentina radicular. Não houve correlação entre o pH das bebidas e o seu potencial erosivo

The aim of this study was to investigate the effects of some acidic drinks on dentin erosion, using methods of surface profile (SP) analysis and energy-dispersive X-ray fluorescence spectrometry (EDXRF). One hundred standardized dentin slabs obtained from bovine incisor roots were used. Dentin slabs measuring 5x5 mm were ground flat, polished and half of each specimen surface was protected with nail polish. For 60 min, the dentin surfaces were immersed in 50 mL of 5 different drinks (Gatorade®, Del Valle Mais orange juice®, Coca-Cola®, Red Bull® and white wine), 20 blocks in each drink. The pH of each beverage was measured. After the erosive challenge, the nail polish was removed and SP was analyzed. The mineral concentration of dentin surfaces was determined by means of EDXRF. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). SP analysis showed that Red-Bull had the highest erosive potential (p<0.05). EDXRF results exhibited a decrease in phosphate in the groups immersed in Red-Bull, orange juice and white wine (p<0.05), and no significant difference in calcium content between the reference surface and eroded surface. In conclusion, this study demonstrated that all studied beverages promoted erosion on root dentin and Red Bull had the highest erosive potential. There was no correlation between pH of beverages and their erosive potential and only the P content changed after erosive challenge.

A influência do tratamento de superfície sobre a resistência adesiva entre uma resina composta (RC), previamente submetida à aplicação de um cimento temporário (CT), e um cimento resinoso foi avaliada. Oitenta e quatro cilindros de RC (5 mm de diâmetro e 3 mm de altura) foram confeccionados e incluídos em resina acrílica. Os conjuntos foram divididos em 6 grupos (G1 a G6) (n=12). Os grupos de 2 a 6 receberam uma camada do CT. Após 24 h, o CT foi removido e as superfícies de RC receberam os seguintes tratamentos: G2: limpeza com etanol; G3: limpeza com escova rotatória e pedra pomes; G4: jateamento ; G5: jateamento e aplicação de adesivo; G6: jateamento, condicionamento ácido e adesivo. O G1(controle) não recebeu CT ou nenhum tratamento de superfície. Os conjuntos foram adaptados à matriz e receberam incremento de cimento resinoso. Os corpos de prova foram submetidos ao ensaio de cisalhamento. Os testes ANOVA e Tukey (p=0,001), demonstraram que os grupos G3 (8,53 MPa) e G4 (8,63 MPa) diferiram estatisticamente do grupo G1 (13,34 MPa). As maiores valores médios de resistência ao cisalhamento foram encontradas nos grupos G5 (14,78 MPa) e G6 (15,86 MPa). O jateamento da superfície da resina composta associado a um sistema adesivo, independente do pré-tratamento com o ácido fosfórico, proporcionou uma efetiva união ao cimento resinoso.

This study evaluated the influence of surface treatment on the shear bond strength of a composite resin (CR), previously submitted to the application of a temporary cement (TC), to an adhesive luting cement. Eight-four CR cylinders (5 mm diameter and 3 mm high) were fabricated and embedded in acrylic resin. The sets were divided into 6 groups (G1 to G6) (n=12). Groups 2 to 6 received a coat of TC. After 24 h, TC was removed and the CR surfaces received the following treatments: G2: ethanol; G3: rotary brush and pumice; G4: air-abrasion; G5: air-abrasion and adhesive system; G6: air-abrasion, acid etching and adhesive system. G1 (control) did not receive TC or any surface treatment. The sets were adapted to a matrix and received an increment of an adhesive luting cement. The specimens were subjected to the shear bond strength test. ANOVA and Tukeyʼs tests showed that G3 (8.53 MPa) and G4 (8.63 MPa) differed significantly (p=0.001) from G1 (13.34 MPa). The highest mean shear bond strength values were found in G5 (14.78 MPa) and G6 (15.86 MPa). Air-abrasion of CR surface associated with an adhesive system provided an effective bond of the CR to the adhesive luting cement, regardless the pre-treatment with the phosphoric acid.

Owing to improvements in its mechanical properties and to the availability of shade and translucence resources, resin composite has become one of the most widely used restorative materials in present day Dentistry. The aim of this study was to assess the relation between the surface hardness of seven different commercial brands of resin composites (Charisma, Fill Magic, Master Fill, Natural Look, Opallis, Tetric Ceram, and Z250) and the different degrees of translucence (translucid, enamel and dentin). Vickers microhardness testing revealed significant differences among the groups. Z250 was the commercial brand that showed the best performance in the hardness test. When comparing the three groups assessed within the same brand, only Master Fill and Fill Magic presented statistically significant differences among all of the different translucencies. Natural Look was the only one that showed no significant difference among any of the three groups. Charisma, Opallis, Tetric Ceram and Z250 showed significant differences among some of the tested groups. Based on the results found in this study, it was not possible to establish a relation between translucence and the microhardness of the resin composites assessed. Depending on the material assessed, however, translucence variation did affect the microhardness values of the resin composites.

Tooth shade results from the interaction between enamel color, enamel translucency and dentine color. A change in any of these parameters will change a tooth’s color. The objective of this study was to evaluate the changes occurring in enamel translucency during a tooth whitening process. Fourteen human tooth enamel fragments, with a mean thickness of 0.96 mm (± 0.3 mm), were subjected to a bleaching agent (10% carbamide peroxide) 8 hours per day for 28 days. The enamel fragment translucency was measured by a computer controlled spectrophotometer before and after the bleaching agent applications in accordance with ANSI Z80.3-1986 - American National Standard for Ophthalmics - nonprescription sunglasses and fashion eyewear-requirements. The measurements were statistically compared by the Mann-Whitney non-parametric test. A decrease was observed in the translucency of all specimens and, consequently, there was a decrease in transmittance values for all samples. It was observed that the bleaching procedure significantly changes the enamel translucency, making it more opaque.