Bottom/top hardness ratio and dentin bonding stability of conventional and bulk-fill resin composites

Aim: To evaluate the bottom/top hardness ratio (B/T) and the dentin bonding stability of conventional and bulk-fill resin composites in high c-factor preparations. Methods: Regular conventional (Tetric N-Ceram ­ TNC, and Polofil Supra ­ PFS), regular bulk-fill (Tetric N-Ceram Bulk fill ­ TBF, and Admira Fusion X-tra ­ AFX), and low viscosity bulk-fill resin composites (Tetric N-flow ­ TNF, and X-tra Base ­ XTB) were used to restore 180 dentin conical preparations. The specimens were randomly distributed in 12 groups (n = 15) according to the resin composites and storage time-points (24 h and six months) tested. After 24 h storage, all specimens were subjected to the bottom/top hardness ratio analysis. Then, the push-out bond strength test was performed in half of the specimens and the other half were maintained for six months on water storage before testing. The failure modes were analyzed in a stereomicroscopic. The data were analyzed statistically using one- and two-way ANOVA and Tukey post-test (p <0.05). Results: There were no statistically significant differences for the bottom/top hardness ratio among the resin composites (p>0.05). Regardless of the storage timepoint, regular bulk-fill resin composites showed the highest bond strength values statistically (p<0.05). Only conventional resin composites showed statistically lower bond strength values at six-month storage (p<0.05). Adhesive failures were more predominant for low-viscosity bulk-fill resin composites. Conclusion: Although the DoC was not affected by different materials tested, only bulk-fill resin composites did not present dentin bond strength loss after six-month of water storage

Avaliação in vitro da razão base/topo de dureza e da resistência de união push-out entre uma resina composta contendo diatomita e uma resina composta bulk-fill / In vitro evaluation of the base/top hardness ratio and push-out bond strength between a diatomite-containing composite resin and a bulk-fill composite resin

A escassez de dados científicos que validem os benefícios da diatomita para as propriedades físicas da resina composta Zirconfill® torna imperioso a realização de novos estudos, principalmente no tocante a utilização dessa resina contendo diatomita em restaurações semidiretas. Objetivo: Avaliar in vitro a polimerização e resistência de união entre uma resina composta contendo diatomita e de uma resina composta bulk-fill após 24 horas e após 06 meses de envelhecimento em água. Materiais e métodos: Foram utilizados 28 incisivos bovinos para produzir cavidades dentinárias cônicas (4,8 mm de diâmetro maior x 2,8 mm de diâmetro menor x 4 mm de espessura) e fator C de magnitude 3,1. Esses preparos cavitários (n=28) foram restaurados com as resinas compostas Filtek™ One Bulk-fill (BF) (3M ESPE) ou Zirconfill ® (ZF) (BM4), através da técnica semidireta, utilizando o sistema adesivo Single Bond Universal (3M ESPE) e o cimento resino dual Relyx™ Ultimate (3M ESPE). A análise da polimerização foi realizada através da razão base/topo (B/T) de dureza Vickers. E a resistência de união RU foi realizada através do teste de extrusão push-out em máquina de ensaio universal. As amostras foram armazenadas em água destilada a 37 ºC por 24 horas ou 06 meses, mas apenas a RU avaliou as amostras após 06 meses de envelhecimento. Os dados da B/T e da RU foram submetidos à análise de variância (ANOVA) a um e a dois critérios, respectivamente, com pós-teste de Tukey (p <0.05). Resultados: Não houve diferença estatisticamente significativa entre as resinas compostas na B/T. Para a RU, a resina composta ZF mostrou valores maiores do que a resina BF em ambos os tempos avaliados. Não houve diferença estatisticamente significativa de nenhuma resina na avaliação ao longo do tempo. Conclusão: A resina composta contendo diatomita mostrou-se promissora quando utilizada em restaurações semidiretas, visto que obteve resultados similar e até superior a resina composta bulk-fill (AU).

The scarcity of data validating scientific diatomite benefits for physical properties of Zirconfill® resin composite makes essential to develop new studies, especially regarding the use of this resin composite containing diatomite in semi-direct restorations. Aim: To evaluate in vitro the cure and bond strength between a resin composite containing diatomite and a bulk-fill resin composite after 24 hours and after 06 months of water storage. Materials and methods: Twenty-eight bovine incisors (n=28) were used to produce conical dentinal cavities (4,8 mm of larger diameter x 2,8 mm of smaller diameter x 4 mm of thickness) and C-factor of magnitude 3.1. These cavities were restored with Filtek™ One Bulk-Fill (BF) (3M ESPE) or Zirconfill® (ZF) (BM4) resin composites, through the semi-direct technique, using Scotchbond™ Universal (3M ESPE) adhesive system and Relyx™ Ultimate (3M ESPE) dual resin cement. The cure analysis was performed through bottom-to-top (B/T) ratio of vickers hardness, while bond strength (RU) was performed through the push-out test in a universal testing machine. The specimens were stored in distilled water at 37 ºC for 24 hours or 06 months, but only RU analyzed the specimens after 06 months aging. B/T and RU data were, respectively, submitted to one-way and two-way analysis of variance (ANOVA) with Tukey's post-test (p <0.05). Results: There was no statistically significant difference between the composite resins in B/T. For RU, the ZF composite resin showed higher values than the BF resin at both evaluated times. However, there was no statistically significant difference in resin composites over time. Conclusion: The resin composite containing diatomite showed promise when used in semi-direct restorations since it obtained similar or even superior results to bulk-fill resin composite (AU).

Enhancing glass ionomer cement features by using the calcium phosphate nanocomposite

Abstract This study showed the synthesis of Glass ionomer cements (GIC) modified with calcium phosphate nanoparticles (nCaP). The nCaP/GIC were submitted to mechanical compression and diametral tensile tests. The biocomposite were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Cytotoxicity and cell viability tests were performed on the human bone marrow mesenchymal stem cells using a 3-(4,5-dimethylthiazol-2yl)2,5-diphenyl- tetrazolium-bromide assay and LIVE/DEAD assays. Statistically significant differences were observed for mechanical properties (Kruskal-Wallis, p<0.001), nCaP/GIC showed higher resistance to compression and diametral traction. The SEM analyses revealed a uniform distribution nCaP in the ionomer matrix. The EDX and XRD results indicated that hydroxyapatite and calcium β-triphosphate phases. The FTIR spectra revealed the asymmetric band of ν3PO43- between 1100-1030cm-1 and the vibration band associated with ν1PO43- in 963cm-1 associated with nCaP. The nCaP/GIC presented response to adequate cell viability and non-cytotoxic behavior. Therefore, the new nCaP/GIC composite showed great mechanical properties, non-cytotoxic behavior, and adequate response to cell viability with promising dental applications.

Resumo Este estudo apresenta a síntese de cimentos de ionômero de vidro (GIC) modificados com nanopartículas de fosfato de cálcio (nCaP). Os nCaP / GIC foram submetidos a ensaios mecânicos de compressão e tração diametral. Os biocompósitos foram caracterizados por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva de raios-X (EDX), difração de raios-X (XRD) e espectroscopia de infravermelho com transformada de Fourier (FTIR). Os testes de citotoxicidade e viabilidade celular foram realizados em células-tronco mesenquimais da medula óssea humana usando um ensaio de 3- (4,5-dimetiltiazol-2-il) 2,5-difeniltetrazólio-brometo e ensaios LIVE / DEAD. Diferenças estatisticamente significativas foram observadas para as propriedades mecânicas (Kruskal-Wallis, p <0,001), nCaP / GIC apresentou maior resistência à compressão e tração diametral. As análises de SEM revelaram uma distribuição uniforme de nCaP na matriz do ionômero. Os resultados de EDX e DRX indicaram fases de hidroxiapatita e β-trifosfato de cálcio. Os espectros de FTIR revelaram a banda assimétrica de ν3PO4 3- entre 1100-1030cm-1 e a banda de vibração associada a ν1PO4 3- em 963cm-1 associada a nCaP. O nCaP / GIC apresentou resposta adequada à viabilidade celular e comportamento não citotóxico. Portanto, o novo compósito nCaP / GIC apresentou ótimas propriedades mecânicas, comportamento não citotóxico e resposta adequada à viabilidade celular com promissoras aplicações odontológicas.

Hydroxyapatite and Biopolymer Composites with Promising Biomedical Applications

ABSTRACT The purpose of tissue engineering (regenerative medicine) is to develop materials that replace human tissue, having as main characteristics' biodegradability, biocompatibility, no toxicity, osteoconductivity, which lead to cell maturation and proliferation. Due to the importance of the development of this type of materials, several researchers have used biopolymers and calcium phosphate salts (hydroxyapatite) as composites to be used in this area as drug releases, scaffolds, implants, among others. Different biopolymers can be suitable for this type of application, in this work we have described the most widely used biopolymers for biomedical purposes, such as alginate, collagen, gellan gum, chitosan, and polylactic acid, in addition to a detailed description of hydroxyapatite, biopolymers, as well as biopolymer/hydroxyapatite composites, to highlight their potential and the most relevant characteristics of these materials.

Desempeño Mecánico de Compuestos de Madera Plástica de Matriz Poliolefínica / Mechanical performance of polyolefinic wood plastic composites / Desempenho mecânicos de compostos de Madeira Plástica de Matriz Poliolefina

Resumen Los polímeros termoplásticos, pueden ser mezclados con diferentes tipos de cargas con el propósito de mejorar su rendimiento físico-mecánico, al mismo tiempo que permiten en muchos casos, generar soluciones a problemáticas ambientales como por ejemplo la disposición final de residuos de madera. Los compuestos de madera plástica son productos elaborados mediante la incorporación de fibras o partículas de madera en la matriz polimérica, donde la interacción entre los dos materiales (nula o con acople) es clave para lograr un adecuado desempeño del producto final. En esta revisión se establecen las matrices poliméricas y los tipos de maderas empleadas comúnmente en la elaboración de productos de madera plástica, al mismo tiempo que se definen los tratamientos previos que deben ser realizados tanto en la madera como en el polímero con el propósito de mejorar la compatibilidad de los dos materiales, y de esta manera mejorar propiedades como la absorción de agua, la resistencia a la descomposición, a la intemperie y el desempeño mecánico. En cuanto a las propiedades mecánicas, al adicionar un contenido de madera en el polímero se modifica la rigidez del material polimérico y la resistencia en tensión, flexión e impacto; sin embargo, se establece que es clave el uso de agentes funcionalizantes para que el efecto de la incorporación de la madera en polímero sea positivo. Finalmente se estudian las nuevas tendencias en el uso de diferentes tipos de residuos y matrices poliméricas para la elaboración de maderas plásticas.

Abstract Polymeric materials, especially thermoplastics, can be mixed with different types of fillers to improve their physical-mechanical performance, at the same time they allow, in many cases, to generate solutions to environmental problems such as the final disposal of wood waste. The plastic wood composites are products made by incorporating wood fibers in the polymer matrix, where the interaction between the two materials is key to achieve an adequate performance of the final product. This review establishes the polymer matrices and the types of wood commonly used in the production of plastic wood products, at the same time defining the previous treatments that must be carried out in the wood and in the polymer to improve the compatibility of the two materials, and in this way improve properties such as water absorption, resistance to decomposition, resistance to weathering and mechanical performance. Related to the mechanical properties, adding the wood fibers in the polymer modifies the rigidity of the polymeric material and the resistance in tension, bending and impact; however, it is established that the use of functionalizing agents is a fundamental key to improve the effect of wood incorporation into the polymer matrix. Finally, the new trends in the use of different types of waste and polymeric matrices to produce plastic wood are studied.

Resumo Os materiais poliméricos, principalmente os termoplásticos, podem ser misturados a diferentes tipos de cargas para melhorar seu desempenho físico-mecânico, ao mesmo tempo que, em muitos casos, permitem gerar soluções para problemas ambientais como a destinação final de resíduos. madeira. Os compósitos madeira-plástico são produtos obtidos pela incorporação de fibras de madeira à matriz polimérica, onde a interação entre os dois materiais é fundamental para um desempenho adequado do produto final. Nesta revisão, são estabelecidas as matrizes poliméricas e os tipos de madeira comumente utilizados na produção de produtos plásticos de madeira, ao mesmo tempo em que são definidos os tratamentos anteriores que devem ser realizados na madeira e no polímero para melhorar a compatibilidade dos dois materiais, e desta forma melhorar propriedades como absorção de água, resistência à decomposição, intempéries e desempenho mecânico. Em relação às propriedades mecânicas, ao adicionar as fibras de madeira ao polímero, a rigidez do material polimérico e a resistência à tração, flexão e impacto são modificadas; porém, está estabelecido que o uso de agentes funcionalizantes é fundamental para que o efeito da incorporação da madeira no polímero seja positivo. Por fim, são estudadas as novas tendências no uso de diferentes tipos de resíduos e matrizes poliméricas para a produção de madeira plástica.

Experimental composite containing silicon dioxide-coated silver nanoparticles for orthodontic bonding: Antimicrobial activity and shear bond strength

ABSTRACT Objective: This study aimed to investigate the antimicrobial activity and shear bond strength (SBS) of orthodontic brackets to bovine enamel using experimental composites with different concentrations of silicon dioxide-coated silver nanoparticles (Ag@SiO2 NPs). Methods: Fifty bovine incisors were divided into five groups according to the composite (n = 10): G1 - Control Group (Transbond XT Resin), G2 - Experimental composite without Ag@SiO2 NPs; G3 - Experimental composite with 0.5% of Ag@SiO2 NPs; G4 - Experimental composite with 1% of Ag@SiO2 NPs; G5 - Experimental composite with 3% of Ag@SiO2 NPs. The SBS test was performed using a universal mechanical testing machine, and the adhesive remnant index (ARI) was analyzed by optical microscopy. For the antimicrobial activity evaluation, Streptococcus mutans (S. mutans) biofilm was formed for three days in hydroxyapatite discs. Posteriorly, S. mutans colony forming units (CFU) were evaluated. For SBS analysis, Analysis of Variance was used, followed by the Tukey test, at a 5% statistical significance level. The CFU data were analyzed by Kruskal-Wallis, followed by Dunn as a post-hoc test. The ARI results were analyzed descriptively. Results: There was no statistically significant difference in SBS values between the experimental and control groups (p>0.05). A 3% incorporation of Ag@SiO2 NPs statistically reduced the SBS values (p<0.05) compared to the 1% group. The addition of 3% of Ag@SiO2 NPs to the composites significantly reduced S. mutans biofilm formation, compared to group G2 (p<0.05). Conclusion: Composites incorporating 3% of Ag@SiO2 NPs presented similar SBS values compared to the control group, and showed significant antimicrobial activity.

RESUMO Objetivo: O presente estudo objetivou investigar a atividade antimicrobiana e a resistência de união ao cisalhamento (RU) de braquetes ortodônticos colados em esmalte bovino, utilizando compósitos experimentais com diferentes concentrações de nanopartículas de prata revestidas com dióxido de silício (NPs Ag@SiO2). Material e Métodos: Cinquenta incisivos bovinos foram divididos em cinco grupos, de acordo com o compósito utilizado (n = 10): G1 - Grupo Controle (Resina Transbond XT); G2 - Compósito Experimental sem NPs Ag@SiO2; G3 - Compósito Experimental com 0,5% de NPs Ag@SiO2; G4 - Composto Experimental com 1% de NPs Ag@SiO2; e G5 - Compósito Experimental com 3% de NPs Ag@SiO2. O teste de RU foi realizado em máquina universal de ensaios mecânicos, e o índice de adesivo remanescente (IAR) foi analisado por microscopia óptica. Para a avaliação da atividade antimicrobiana, biofilme de S. mutans foi formado por três dias em discos de hidroxiapatita. Posteriormente, foram avaliadas as unidades formadoras de colônias (UFC) de S. mutans. Para a análise de RU, foi utilizada a Análise de Variância, seguida do teste de Tukey, com nível de significância estatística de 5%. Os dados de UFC foram analisados por meio do teste de Kruskal-Wallis, seguido do teste post-hoc de Dunn. Os resultados de IAR foram analisados descritivamente. Resultados: Não houve diferença estatisticamente significativa nos valores de RU entre os grupos experimentais e o grupo controle (p> 0,05). A incorporação de 3% de NPs Ag@SiO2 reduziu estatisticamente os valores de RU (p< 0,05), em comparação ao grupo com 1%. A adição de 3% de NPs Ag@SiO2 ao compósito reduziu significativamente a formação de biofilme de S. mutans, em relação ao grupo G2 (p< 0,05). Conclusão: Os compósitos com incorporação de 3% de NPs Ag@SiO2 apresentaram valores de RU semelhantes ao grupo controle e demonstraram significativa atividade antimicrobiana.

Comparative evaluation of antibacterial efficacy different bioactive smart composites An in vitro study

Background: Composites are the widely used restorative materials, and over the year, newer restorative composites have been introduced to eliminate the drawbacks of previous ones. The recent advance in restorative dentistry is bioactive restorative materials. However, bacterial plaque formation on these restorations is the primary reason for secondary caries. Aims and objectives: The purpose of this study was to do the comparative evaluation of bioactive restorative composites (Beautifil Flow Plus, Activa BioACTIVE, and Filtek Z250 XT as control) for their antibacterial efficacy under in vitro conditions. Materials and Method: Thirty material blocks were used for this evaluation. Antibacterial efficacy was checked against Streptococcus mutans and observed under confocal laser scanning microscopy. Results: The results showed that Activa BioACTIVE shows maximum number of dead bacteria on the material surface compared to other groups. Conclusion: It can be concluded as it has maximum antibacterial efficacy among tested materials.

Do dual-cure bulk-fill resin composites reduce gaps and improve depth of cure

Abstract This in vitro study aimed to evaluate the gaps length and depth of cure of dual-cure bulk-fill resin composites inserted in box-shaped preparations. Box-shaped preparations (4 mm deep) were made in fifteen human third-molars and divided into three groups according to the resin composites (n=5): Dual-cure bulk-fill BulkEZ (BEZ); Dual-cure bulk-fill HyperFIL (HF); and Tetric Evoceram Bulk-fill (TETRIC), as control. Gaps length (%) was evaluated in tooth-restoration interface with micro-computed tomography (µCT). The restorations were sectioned, and the degree of conversion (DC) and Knoop microhardness were evaluated at five depths (0.3, 1, 2, 3, and 4 mm). Microhardness data were statistically evaluated using absolute values (KHN) and relative values (microhardness percentages in relation to top). Gaps length (%) increased in the following order: BEZ=TETRIC<HF. The microhardness percentages in relation to top significantly decreased from 2 mm for TETRIC and 3 mm for HF. BEZ had constant microhardness and DC at all depths, while HF and TETRIC presented a significant decrease on DC at 4 mm. Dual-cure bulk-fill composites did not reduce gaps compared to light-cure bulk-fill, but they can improve depth of cure of bulk-filled restorations.

Resumo O objetivo neste estudo in vitro foi mensurar as fendas e a profundidade de polimerização de compósitos resinosos bulk-fill duais inseridos em preparos em forma de caixa. Os preparos em forma de caixa (4 mm de profundidade) foram realizados em quinze terceiros molares e separados em 3 grupos, de acordo com o compósito resinoso (n = 5): Bulk-fill dual BulkEZ (BEZ); Bulk-fill dual HyperFIL (HF); Tetric Evoceram Bulk-fill (TETRIC). O comprimento das fendas (%) foi avaliado na interface dente-restauração por meio de micro-tomografia computadorizada (µCT). As restaurações foram seccionadas e o grau de conversão (GC) e microdureza Knoop foram avaliados em cinco profundidades (0,3, 1, 2, 3 e 4 mm). Os dados de microdureza foram avaliados estatisticamente por meio de valores absolutos e relativos (porcentagens de microdureza em relação ao topo). O comprimento das fendas (%) aumentou na seguinte ordem: BEZ = TETRIC <HF. O percentual de microdureza em relação ao topo diminuiu significativamente a partir de 2 mm para TETRIC e 3 mm para HF. BEZ apresentou percentuais de microdureza e de GC constantes em todas as profundidades, enquanto HF e TETRIC apresentaram decréscimo significativo no GC em 4 mm. Os compósitos resinosos bulk-fill duais não reduziram as fendas formadas quando comparados a um compósito bulk-fill fotopolimerizável; entretanto, os mesmos podem melhorar a profundidade de polimerização em restaurações de incremento único.

Discoloration of Bulk-Fill Versus Conventional Composites: A Spectrophotometric Evaluation / Decoloración de resinas Bulk vs resinas convencionales: Evaluación espectrofotométrica

ABSTRACT: Purpose: The purpose of this study was to evaluate the discoloration of a dual-cure bulk-fill (DCBF) and light-cure bulk-fill (LCBF) composites relative to conventional composites (CC) after water and coffee immersion. Methods: One- hundred disc-shaped specimens (8mm in diameter × 4mm thickness) were prepared using five commercially available composites (n=10); two LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), one DCBF (FU-Fill-upTM Coltene), and two CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Initial and final color readouts were measured with a spectrophotometer (Easyshade,Vita) according to the CIELAB color system. Statistical analyses were performed using 2-way ANOVA with Bonferroni adjustment to evaluate ΔE, ΔL, Δa, and Δb parameters (pFB≥XB>EQ≥CE in water immersion groups and XB>FB>EQ≥FU≥CE in coffee immersion groups. Conclusion: Within the limitations of this study, DCBF composite is more susceptible to intrinsic discoloration compared to LCBF and CC. However, DCBF exhibited lower extrinsic discoloration than LCBF and comparable with CC after coffee immersion. Depending on their chemical and structural compositions, composites will exhibit color change, which compromises the esthetic performance of composite restorations.

RESUMEN: Propósito: El propósito de este estudio fue evaluar la decoloración de resinas bulk de curado dual (DCBF) y bulk activadas por fotopolimerización (LCBF) en relación con las resinas convencionales (CC) después de la inmersión en agua y café. Métodos: Se prepararon cien muestras en forma de disco (8mm de diámetro × 4mm de espesor) utilizando cinco resinas compuestas disponibles comercialmente (n=10); dos LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), un DCBF (FU-Fill-upTM Coltene) y dos CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Las lecturas de color inicial y final se midieron con un espectrofotómetro (Easyshade, Vita) de acuerdo con el sistema de color CIELAB. Los análisis estadísticos se realizaron utilizando ANOVA de 2 vías con ajuste de Bonferroni para evaluar los parámetros ΔE, ΔL, Δa y Δb (pFB≥XB>EQ≥CE en los grupos de inmersión en agua y XB>FB>EQ≥FU≥CE en los grupos de inmersión en café. Conclusión: Dentro de las limitaciones de este estudio, la resina DCBF es más susceptible a la decoloración intrínseca en comparación con LCBF y CC. Sin embargo, DCBF mostró una decoloración extrínseca más baja que LCBF y comparable con CC después de la inmersión en café. Dependiendo de sus composiciones químicas y estructurales, los composites mostrarán cambios de color, lo que compromete el desempeño estético de las restauraciones de resinas con el tiempo.

Post-cure heat treatments influence on mechanical and optical properties of resin composites

Abstract This study evaluated the effect of post-cure heat treatment (PCHT) on the Knoop microhardness (KHN), degree of conversion (DC), color changes, and contrast ratio (CR) of four resin composites (RCs): Z100 (3M ESPE), Z350 XT (3M ESPE), Estelite Omega (Tokuyama) and Empress Direct (Ivoclar Vivadent). Specimens (12 × 1 mm) were prepared for each material (n = 10 / group). After curing, samples were subjected to PCHT for 10 min at 100°C or 170°C. Control group was maintained at room temperature (24°C) for the same time. The DC was analyzed by FT-NIR immediately and 24 h after the PCHT (n = 3 / group). KHN was analyzed 24 h after PCHT (n = 10 / group). According to CIEDE2000 (∆E00), color measurements were obtained immediately after curing, five minutes after PCHT, and after seven days of storage in water, coffee, and red wine. Data were analyzed by One and Two-Way ANOVA (p < 0.05). Z100, Z350, and Estelite Omega showed increases in KHN with increased temperature (p < 0.05). PCHT at 100°C and 170°C led to a higher DC of all RCs (p < 0.05). Initially, the PCHT lead to increased ∆E00 values (p < 0.05), which was decreased after immersion in coffee and wine (p < 0.05). Considering the effect of PCHT and staining solutions, lower color changes were observed in the thermally treated specimens (p < 0.05). Taken collectively, the results suggest the PCHT as an economical and practical alternative to enhance direct RC's properties in direct-indirect and indirect restorations.

Resumo Este estudo avaliou o efeito do tratamento térmico pós-cura (PCHT) na microdureza Knoop (KHN), grau de conversão (DC), mudanças de cor e razão de contraste (CR) de quatro compósitos resinosos (RCs): Z100 (3M ESPE ), Z350 XT (3M ESPE), Estelite Omega (Tokuyama) e Empress Direct (Ivoclar Vivadent). Corpos de prova (12 × 1 mm) foram preparadas para cada material (n = 10 / grupo). Após a cura, as amostras foram submetidas ao PCHT por 10 min a 100 ou 170° C. O grupo controle foi mantido à temperatura ambiente (24° C) pelo mesmo tempo. O DC foi analisada por FT-NIR imediatamente e 24 h após a PCHT (n = 3 / grupo). KHN foi analisado 24 h após PCHT (n = 10 / grupo). De acordo com o CIEDE2000 (∆E00), as medidas de cor foram obtidas imediatamente após a cura, cinco minutos após a PCHT e após sete dias de armazenamento em água, café e vinho tinto. Os dados foram analisados por ANOVA de um e dois fatores (P < 0,05). Z100, Z350 XT e Estelite Omega mostraram aumentos no KHN com o aumento da temperatura (P < 0,05). PCHT a 100 ° C e 170 ° C levou a uma maior DC de todos os RCs (P < 0,05). Inicialmente, o PCHT levou ao aumento dos valores de ∆E00 (P < 0,05), que diminuiu após a imersão em café e vinho (P < 0,05). Considerando o efeito de PCHT e soluções de coloração, menores mudanças de cor foram observadas nas amostras tratadas termicamente (P < 0,05). Os resultados sugerem o PCHT como uma alternativa econômica e prática para aumentar as propriedades diretas de compósitos resinosos em restaurações diretas-indiretas e indiretas.

CHX stabilizes the resin/demineralized dentin interface

Abstract The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on microtensile bond strength (µTBS) between an adhesive system and under 3 dentin conditions. For that, this study evaluated the adhesive interface at initial, after 6 months and 1 year of storage. Forty-eight human third molars were prepared and randomly divided into 3 groups, according to dentin substrates: sound dentin (Sd), caries-infected dentin (Ci) and caries-affected dentin (Ca). The groups were subdivided into two according to the dentin pre-treatment: application of 2% CHX or without pre-treatment (control). The dentin surfaces were etched with 35% phosphoric acid gel and bonded with Adper Single Bond 2 (3M ESPE) adhesive system according to manufacturer's instructions. Subsequently, the specimens were stored in deionized water at 37°C for 24h, 6 months and 1 year. Two additional teeth were used to analyze the bonding interfaces by SEM. Data was submitted to three-way ANOVA in a split plot design and Tukey's test (α = 0.05). The results showed that Ci decreased µTBS values when compared to Ca and Sd, regardless storages time or treatment. Stored samples for 6 months and 1 year decreased the µTBS for the control group, but no difference was found between storages time for the CHX group. As a conclusion, the 2% CHX application after etching showed improved dentin bond strength in the storage time, regardless of the substrates evaluated.

Resumo O objetivo deste estudo foi avaliar o efeito do digluconato de clorexidina 2% (CHX) na resistência de união à microtração (µTBS) entre um sistema adesivo e sob 3 condições de dentina. Para tanto, este estudo avaliou a interface adesiva no início, após 6 meses e 1 ano de armazenamento. Quarenta e oito terceiros molares humanos foram preparados e divididos aleatoriamente em 3 grupos, de acordo com os substratos dentinários: dentina hígida (Dh), dentina infectada por cárie (Di) e dentina afetada por cárie (Da). Os grupos foram subdivididos em dois de acordo com o pré-tratamento: aplicação de CHX 2% ou sem pré-tratamento (controle). As superfícies da dentina foram condicionadas com gel de ácido fosfórico a 35%, em seguida, utilizou-se o sistema adesivo Adper Single Bond 2 (3M ESPE) de acordo com as instruções do fabricante. Posteriormente, os corpos-de-prova foram armazenados em água deionizada a 37°C por 24h, 6 meses e 1 ano. Dois dentes adicionais foram usados ​​para analisar as interfaces de união no MEV. Os dados foram submetidos a ANOVA três fatores em esquema de parcela subdividida e ao teste de Tukey (α = 0,05). Os resultados mostram que a Di diminuiu os valores de µTBS quando comparado as Da e Dh, independente do tempo de armazenamento ou tratamento. Amostras armazenadas por 6 meses e 1 ano diminuíram a µTBS para o grupo de controle, mas nenhuma diferença foi encontrada entre o tempo de armazenamento para o grupo CHX. A aplicação de CHX 2% após o condicionamento apresentou melhora na resistência de união à dentina no tempo de armazenamento, independente dos substratos avaliados.

Color Stability and Surface Roughness of Hybrid and Nanofilled Composites Brushed with Abrasive Dentifrices / Estabilidade de Cor e Rugosidade Superficial de Resinas Compostas Micro-Híbridas e Nanoparticulada Submetidas à Escovação com Dentifrícios Abrasivos

The aim of this study was to evaluate the color stability and the surface roughness of different composites brushed with toothpastes presenting different levels of abrasivity. Thirty discs of each material were obtained using michohybrid composites (Brilliant NG and Charisma Diamond) and a nanocomposite (Filtek Z350XT). The initial color (CIELab) and surface roughness (confocal laser scanning microscopy) of resin discs were evaluated. Afterwards, 10 specimens per group were brushed with the following dentifrices: Maximum Cavity Protection, Sensodyne Repair & Protect and Colgate Sensitive Pro-Relief. Brushing was performed with an electric toothbrush equipped with soft bristle head, with standard power and weight, for 30 minutes. Every 30 seconds, 1.0 ml of the slurry was injected between the bristles of the brush and the specimen. After abrasive challenge, the samples had their color and roughness reevaluated. Data were submitted to the Kruskal-Wallis test (color change) or the t-test (surface roughness). The level of significance was 5%. Results: Brushing did not significantly change the color of the composites tested in the study herein . On the other hand, the surface roughness of the composites was significantly affected by the abrasive challenge, regardless of the toothpaste used. The surface roughness change was similar for all the composites. The abrasive challenge with the toothpastes Maximum Cavity protection, Sensodyne Repair & Protect and Colgate Sensitive Pro-Relief was not able to significantly change the color of the composite resins. Nevertheless, the abrasive challenges significantly altered the surface roughness of all the evaluated composites. However, the changes in surface roughness were statistically similar in the microhybrid and nanofilled composites. (AU)

O objetivo deste estudo foi avaliar a estabilidade de cor e a rugosidade superficial de diferentes resinas compostas escovadas com dentifrícios de diferentes níveis de abrasividade. Trinta discos de cada material foram obtidos utilizando compósitos micro-híbridos (Brilliant NG e Charisma Diamond) e um nanocompósito (Filtek Z350XT). A cor inicial (CIELab) e a rugosidade superficial (microscopia confocal de varredura a laser) dos discos de resina foram avaliadas. Em seguida, 10 amostras por grupo foram escovadas com os dentifrícios Máxima Proteção Anticáries, Sensodyne Repair & Protect e Colgate Sensitive Pro-Alívio. A escovação foi realizada com uma escova elétrica com cabeça de cerdas macias, com potência e peso padronizados, durante 30 minutos. A cada 30 segundos, 1,0 ml da pasta era injetada entre as cerdas da escova e a amostra. Após o desafio abrasivo, as amostras tiveram sua cor e rugosidade reavaliadas. Os dados foram submetidos ao teste de Kruskal-Wallis (alteração de cor) ou ao teste t (rugosidade da superfície) (α=5%). A escovação não alterou significativamente a cor dos compósitos. Por outro lado, a rugosidade superficial dos compósitos foi significativamente afetada pelo desafio abrasivo, independentemente do dentifrício utilizado. A alteração da rugosidade superficial foi semelhante para todos os compósitos. O desafio abrasivo com a Máxima Proteção Anticáries, o Sensodyne Repair & Protect e o Colgate Sensitive Pro-Alívio não foi capaz de alterar significativamente a cor das resinas. Diferentemente, os desafios abrasivos alteraram significativamente a rugosidade superficial de todos os compósitos avaliados. No entanto, as mudanças na rugosidade foram estatisticamente semelhantes nos compósitos micro-híbridos e nanoparticulado. (AU)

Direct-Indirect Technique Restoration for Non-Carious Cervical Lesions Treatment: a Case Report / Técnica Direta-Indireta para Restauração de Lesões Cervicais não Cariosas: um Relato de Caso

Non-Carious Cervical Lesions are characterized by slow and progressive loss of hard tissue at the level of enamel-cement junction, without bacterial involvement. This work aimed to address a case report of restorative treatment in Class V cavities in multiple premolars using the directindirect technique with composite resin. A 42 year-old male patient presented for esthetic restorative treatment with the complaint of severe dentin hypersensitivity and wedged-shaped non-carious cervical lesions affecting the maxillary premolars. The restorative treatment chosen was a direct-indirect technique with composite performed into three sessions as follows: making the class V composite inlays, cementation, and final polishing. The direct-indirect technique as an alternative to the traditional direct technique has the benefits of a better contour of the restoration, since the finishing and polishing are made extraorally. Besides, the control of the polymerization stress and less discomfort to the patient are other advantages. In the case of direct-indirect class V restoration, the advantages far surpass those of the direct technique. (AU)

As Lesões Cervicais Não Cariosas se caracterizam pela perda lenta e progressiva de tecido duro próximo a junção cemento-esmalte, sem envolvimento bacteriano. Este trabalho tem o objetivo de relatar um caso clínico de tratamento restaurador em cavidades do tipo Classe V em pré-molares pela técnica direta-indireta com resina composta. Paciente do sexo masculino, 42 anos, queixava-se de forte sensibilidade e múltiplas Lesões Cervicais Não Cariosas na forma de cunha nos pré-molares superiores. O tratamento restaurador escolhido foi a técnica direta-indireta com resina composta realizado em três sessões distribuídas em confecção da peça em resina composta, cimentação e polimento final. A técnica direta-indireta surge como alternativa a técnica direta tradicional trazendo como benefícios um melhor contorno da restauração, uma vez que esta é acabada e polida fora da boca, além do controle do estresse de polimerização e menor desconforto ao paciente. A intervenção restauradora direta-indireta se mostra eficaz devido ao fato de conseguir contornar dificuldades encontradas em técnicas restauradoras diretas. (AU)

Effect of Dietary Challenges on the Flexural Properties of Resin-based Composites

@#This study aims to compare flexural strength and flexural modulus of different resin-based composites (RBCs) and to determine the impact of dietary solvents on flexural properties. Forty specimens (12x2x2mm) for each of two conventional (Aura Easy [AE]; Harmonize [HN]) and one bulk fill (Sonic Fill 2 [SF2]) were fabricated using customised plastic moulds. Specimens were light-cured, measured and randomly divided into four groups. The groups (n=10) were conditioned for 7 days at 37°C: in one of media: air (control), artificial saliva (SAGF), 0.02N citric acid and 50% ethanol–water solution. After conditioning, the specimens subjected to flexural testing. Two-way ANOVA and one-way ANOVA (post hoc: Tukey’s or Dunnett T3 tests) were used at =0.05. Significant differences in flexural properties were observed between materials and conditioning media. Flexural strength and modulus values ranged from 124.85MPa to 51.25MPa; and 6.76GPa to 4.03GPa, respectively. The highest flexural properties were obtained with conditioning in air. Exposure to aqueous solutions generally reduced flexural properties. In conclusion, the effect of dietary solvents on flexural properties were material and medium dependent. For functional longevity of restorations, patients’ alcohol intake should be considered during material selection. Dietary advice (reduce alcohol consumption) should be given to patients post operatively.

Formation mechanisms of sub-micron pharmaceutical composite particles derived from far-and near-field Raman microscopy / 药物分析学报

Surface enhanced Raman spectroscopy (SERS) and confocal Raman microscopy are applied to investigate the structure and the molecular arrangement of sub-micron furosemide and polyvinylpyrrolidone(furosemide/PVP) particles produced by spray flash evaporation (SFE).Morphology,size and crystallinity of furosemide/PVP particles are analyzed by scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD).Far-field Raman spectra and confocal far-field Raman maps of furosemide/PVP par-ticles are interpreted based on the far-field Raman spectra of pure furosemide and PVP precursors.Confocal far-field Raman microscopy shows that furosemide/PVP particles feature an intermixture of furosemide and PVP molecules at the sub-micron scale.SERS and surface-enhanced confocal Raman microscopy (SECoRM) are performed on furosemide,PVP and furosemide/PVP composite particles sputtered with silver (40 nm).SERS and SECoRM maps reveal that furosemide/PVP particle surfaces mainly consist of PVP molecules.The combination of surface and bulk sensitive analyses reveal that furosemide/PVP sub-micron particles are formed by the agglomeration of primary furosemide nano-crystals embedded in a thin PVP matrix.Interestingly,both far-field Raman microscopy and SECoRM provide molecular information on a statistically-relevant amount of sub-micron particles in a single microscopic map;this combination is thus an effective and time-saving tool for investigating organic sub-micron composites.

Determination of bisphosphonates anti-resorptive properties based on three forms of ceramic materials:Sorption and release process evaluation / 药物分析学报

There is a strong need to search for more effective compounds with bone anti-resorptive properties,which will cause fewer complications than commonly used bisphosphonates.To achieve this goal,it is necessary to search for new techniques to characterize the interactions between bone and drug.By studying their interaction with hydroxyapatite (HA),this study used three forms of ceramic materials,two of which are bone-stimulating materials,to assess the suitability of new active substances with anti-resorptive properties.In this study,three methods based on HA in loose form,polycaprolactone/HA (a polymer-ceramic materials containing HA),and polymer-ceramic monolithic in-needle extraction(MINE) device (a polymer inert skeleton),respectively,were used.The affinity of risedronate (a standard compound) and sixteen aminomethylenebisphosphonates (new compounds with potential anti-resorptive properties) to HA was defined according to the above-mentioned methods.Ten monolithic materials based on 2-hydroxyethyl methacrylate/ethylene dimethacrylate are prepared and studied,of which one was selected for more-detailed further research.Simulated body fluids containing bisphosphonates were passed through the MINE device.In this way,sorption-desorption of bisphosphonates was evaluated using this MINE device.The paper presents the advantages and disad-vantages of each technique and its suitability for assessing new active substances.All three methods allow for the selection of several compounds with potentially higher anti-resorptive properties than risedronate,in hope that it reflects their higher bone affinity and release ability.

Interfacial stress and bond strength of bulk-fill or conventional composite resins to dentin in class ii restorations

Abstract The aim was to evaluate the microtensile bond strength (mTBS) to dentin and interfacial stress in a class II cavity restored with bulk-fill or conventional composite resins and the margin interfaces. Vertical slot class II cavities in the mesial face, with the gingival end in dentin, were prepared in 72 third molars, being divided into groups (n=24): G1-Tetric N-Ceram; G2-Tetric N-Ceram Bulk-Fill; G3-SonicFill. Clearfil SE Bond adhesive system was used in all groups. Half of the teeth in each group (n=12) were submitted to thermo-mechanical cycling (TMC). Restored teeth (n=9) were cut perpendicular to obtain beams, which were submitted to a mTBS test in an EMIC machine. The cervical margins in dentin of the restored teeth (n=3) were assessed using SEM through epoxy resin replicas as well as the section of the restoration. Interfacial stresses after load application were calculated by 2D finite element analysis. The mTBS means-MPa followed by different letters represent statistical difference by ANOVA and Games-Howell's test (p<0.05): Without TMC: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. With TMC: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. Interfacial stress (MPa) was 4.4 for SonicFill, 3.9 for Tetric N-Ceram, and 3.5 for Tetric N-Ceram Bulk-Fill. SEM images showed continuous margins for all composite resin restorations. It was possible to conclude that SonicFill obtained a slightly higher interfacial stress and lower bond strength to dentin in comparison with Tetric N-Ceram and Tetric N-Ceram Bulk-Fill. Continuous margin interfaces were obtained for Tetric N-Ceram, Tetric N-Ceram Bulk-Fill, and SonicFill. However, voids were observed in the SonicFill restorations.

Resumo O objetivo foi avaliar a resistência de união à microtração (RUμT) à dentina e o estresse interfacial em cavidades classe II restauradas com resina composta de incremento único ou convencional e as interfaces marginais. Cavidades classe II na face mesial, com margem gengival em dentina, foram confeccionadas em 72 terceiros molares, sendo divididos em grupos (n=24): Grupo 1-Tetric N-Ceram; Grupo 2- Tetric N-Ceram Bulk-Fill; Grupo 3- SonicFill. O Sistema adesivo Clearfil SE Bond foi usado em todos os grupos. Metade dos dentes de cada grupo (n=12) foram submetidos à ciclagem termo-mecânica (CTM). Os dentes restaurados (n=9) foram cortados perpendicularmente para obter palitos que foram submetidos ao teste de RµT na máquina-EMIC. As margens cervicais em dentina dos dentes restaurados (n=3) foram observados em microscopia eletrônica de varredura (MEV) por meio de réplicas em resina epoxy, assim como os cortes das restaurações. O estresse interfacial após a aplicação da carga foram calculadas por análise de elementos finitos 2D. As médias de RUμT-MPa seguidas de letras distintas apresentam diferença estatística de acordo com ANOVA e teste de Games-Howell (p<0,05): Antes da CTM: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. Após CTM: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. O estresse interfacial (MPa) foi 4,4 para SonicFill, 3,9 para Tetric N-Ceram e 3,5 para Tetric N-Ceram Bulk-Fill. Imagens em MEV mostraram margens contínuas para todas as restaurações em resina composta. Foi possível concluir que o SonicFill obteve um estresse interfacial ligeiramente mais alto e menor resistência de união à dentina em comparação com o Tetric N-Ceram e o Tetric N-Ceram Bulk-Fill. Interfaces de margem contínua foram obtidas para Tetric N-Ceram, Tetric N-Ceram Bulk-Fill e SonicFill. Entretanto, espaços vazios foram observados nas restaurações do SonicFill.

The effect of different finishing and polishing procedures on the surface gloss of Bulk-Fill resin composites

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.

Comparison of antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times

ABSTRACT Introduction: Plaque accumulation can cause white spot lesions. Adding nanoparticles to composites can be effective in reducing the number and function of microorganisms. Objective: The aim of this study was to evaluate the antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times. Methods: Hydroxyapatite, titanium oxides, zinc oxide, copper oxide and silver oxide nanoparticles were prepared at 0.5% and 1% weight concentrations. Accordingly, ten study groups and one control group were obtained. Then, 26 composite discs were prepared from each group. Strain of Streptococcus mutans was cultured, and colonies of Streptococcus mutans were counted. Further bacterial culture was swapped onto enriched Mueller-Hinton agar. The composites were placed on the culture medium, and after incubation the diameter of growth inhibition was measured. To investigate the long-term effect of nanoparticles, the colonies were counted at days 3, 15 and 30. Results: The results showed that 1% copper oxide and 1% silver oxide significantly reduced the number of bacteria (p< 0.05), but there was no significant difference between the other groups and control group (p> 0.05). At day three, there was a significant difference between control group and 0.5% silver oxide, 1% silver oxide and 1% copper oxide groups (p< 0.05). However, colonies had grown in all groups at day 30 but showed no significant difference with control group (p> 0.05). Conclusion: Addition of 1% copper oxide and 1% silver oxide has short-term antibacterial effects, so the clinical use of these nanoparticles cannot be justified.

RESUMO Introdução: O acúmulo de placa bacteriana pode causar lesões de mancha branca. A adição de nanopartículas nas resinas ortodônticas pode ser eficaz para reduzir o número e a função dos microrganismos. Objetivo: O objetivo do presente estudo foi avaliar os efeitos antibacterianos contra o Streptococcus mutans, em diferentes intervalos de tempo, de resinas ortodônticas contendo diferentes tipos de nanopartículas. Métodos: Foram criados dez grupos experimentais e um grupo controle contendo nanopartículas de hidroxiapatita, óxido de titânio, óxido de zinco, óxido de cobre e óxido de prata em concentrações de 0,5% e 1%. Em seguida, foram preparados 26 discos de resina para cada grupo. Colônias de Streptococcus mutans foram cultivadas e contadas. Posteriormente, as culturas bacterianas foram colocadas em solução de ágar Mueller-Hinton. Os discos de resina foram colocados no meio de cultura e, depois da incubação, mediu-se o diâmetro de inibição do crescimento. Para avaliar os efeitos em longo prazo das nanopartículas, as colônias foram analisadas após 3, 15 e 30 dias. Resultados: Os resultados mostraram que o óxido de cobre a 1% e o óxido de prata a 1% reduziram significativamente o número de bactérias (p< 0,05), mas não houve diferença estatisticamente significativa entre os outros grupos e o grupo controle (p> 0,05). Após 3 dias, houve uma diferença significativa entre o grupo controle e os grupos óxido de prata a 0,5%, óxido de prata a 1% e óxido de cobre a 1% (p< 0,05). Porém, após 30 dias, as colônias haviam crescido em todos os grupos, sem diferença com o grupo controle (p> 0,05). Conclusão: A adição de óxido de cobre a 1% e óxido de prata a 1% apresenta efeitos antibacterianos apenas no curto prazo; portanto, o uso clínico dessas nanopartículas não se justifica.

Color stability of ceramic veneers luted with resin cements and pre-heated composites: 12 months follow-up

Abstract The objective was to evaluate the color stability of ceramic veneers luted with resin cements and pre-heated composite resins (60oC) for 12 months, and determine the degree of conversion (DC) of the luting agents. Two resin cements (AllCem Veneer, light-cured (LRC) and AllCem, dual-cured (DRC)] and three composite resins [Z100 (MNCR-minifilled), Herculite Classic (MHCR-micro-hybrid) and Durafill (MCCR-microfilled)] were used for cementing 0.8-mm-thick lithium-silicate glass-ceramic laminates (Suprinity, shade B2-HT, Vita) on bovine enamel (n=10). The specimens were stored at 37oC in distilled water. CIELab parameters were determined at 24h after luting (baseline), 7, 30, 90, 180 days and 12 months. Three specimens were prepared for DC evaluation, performed by micro-Raman spectroscopy. Data were analyzed by ANOVA and Tukey's test (a=5%). For ΔEab and ΔE00, there were significant differences for luting material (p<0.001), time (p<0.001), and double interaction (p<0.001). The groups cemented with MHCR (1 year), MCCR (90 days and 1 year) and MCCR-PH (1 year) were the ones with ΔE values greater than the acceptability threshold. All other groups maintained their ΔE lower than the acceptability threshold after 1 year in distilled water. Regarding DC, there were no significant differences (p=0.127) among the materials. Non-significant negative correlations were observed between the mean ΔEab and DC (R=-0.65) and ΔE00 and DC (R=-0.64). A significant positive correlation was observed mean ΔEab and ΔE00 (R=0.99). It was concluded that the different luting agents influenced the final color of the restorations. The heating of the composite resins did not affect their DC.

Resumo O objetivo foi avaliar a estabilidade de cor de laminados cerâmicos de fina espessura, após a cimentação com cimentos resinosos e resinas compostas em temperatura ambiente e aquecida (60oC), durante 12 meses; bem como determinar o grau de conversão dos diferentes materiais para cimentação. Foram utilizados dois cimentos resinosos [AllCem Veneer, cimento resinoso fotoativado (LRC) e AllCem, cimento resinoso dual (DRC)] e três resinas compostas [Z100 (MNCR - resina composta de partículas finas), Herculite Classic (MHCR - resina composta micro-híbrida) e Durafill (MCCR - resina composta microparticulada)] para cimentação de laminados cerâmicos a base de silicato de lítio (Suprinity, cor B2-HT, Vita Zahnfabrik) com 0,8 mm de espessura, sobre esmalte bovino. Oitenta espécimes foram distribuídos aleatoriamente em 8 grupos de acordo com o material para cimentante (n=10). Os espécimes foram armazenados a 37oC em água destilada. Os parâmetros do CIELab foram determinados 24h após a cimentação (baseline), 7, 30, 90, 180 dias e 12 meses. Outros três espécimes foram preparados para avaliação de grau de conversão, realizada por espectroscopia micro-Raman. Os dados foram analisados por ANOVA e teste de Tukey (a=5%). Para ΔEab e ΔE00, houve diferenças estatisticamente significantes para o material de cimentação (p<0,001), tempo (p<0,001) e interação dupla (p<0,001). Os grupos cimentados com o MHCR (1 ano), MCCR (90 dias e 1 ano) e MCCR-PH (1 ano) foram os únicos com valores de ΔE maiores que o limite de aceitabilidade. Todos os demais grupos mantiveram seu ΔE menor que o limite de aceitabilidade ao final de 1 ano de armazenamento em água destilada. Em relação ao grau de conversão, não foram observadas diferenças estatisticamente significantes entre os materiais para cimentação avaliados (p=0,127). O grau de conversão variou entre 64,0% (MNCR-PH) e 85,1% (DRC). Correlações negativas moderadas a fortes não significativas foram observadas entre a média ΔEab e grau de conversão (R=-0,65) e ΔE00 e grau de conversão (R=-0,64). Observou-se uma correlação positiva forte significativa nos valores médios de ΔEab e ΔE00 (R=0,99). Pode-se concluir que os diferentes agentes cimentantes utilizados na cimentação de laminados cerâmicos de espessura fina influenciaram na cor final das restaurações. O aquecimento das resinas compostas não implicou em alteração do grau de conversão.