Color matching and color recovery in large composite restorations using single-shade or universal composites

Abstract This study assessed the color-matching ability and color recovery of unprepared teeth when using single-shade composites and a universal composite in large restorations. Buccal and palatine surface colors of molars were measured with a spectrophotometer (CIELAB) before preparing round cavities (6 mm in diameter, 2 mm in depth). The cavities were randomly filled with a single-shade composite (Omnichroma, Diamond One, or Vittra APS Unique) or a universal composite (Filtek Universal). Color measurements of the restored cavities were taken, and overall color differences (ΔEab and ΔE00) and differences in the whitening index for dentistry (ΔWID) from baseline were calculated. Additionally, visual assessments of a color match to the surrounding enamel were performed by forty evaluators (laypersons and undergraduate students of dentistry) in a viewing booth under illuminant D65, with rating scores from 0 (no color mismatch) to 4 (not acceptable). Data were analyzed using RM or one-way ANOVA (α = 0.05). Results showed that the restorations generally exhibited whiter colors (WID ranged from 27.9 to 41.3) than the unprepared teeth (WID ranged from 15.9 to 19.3). The composite Filtek Universal demonstrated the lowest color discrepancy (ΔWID = 8.6; ΔE00 = 10.8; and ΔE00 = 6.2), and no significant differences were observed among the evaluated single-shade composites. Furthermore, all composites showed similar and adequate color matches to the surrounding enamel. However, it is important to note that despite their ability to match the surrounding enamel reasonably, none of the composites evaluated in large restorations fully recovered the color observed in unprepared teeth.

Resumo Este estudo avaliou a habilidade de combinação de cores e recuperação de cor de dentes não preparados ao utilizar resinas compostas de única tonalidade e uma resina composta universal em grandes restaurações. As cores das superfícies bucais e palatinas de molares foram medidas com um espectrofotômetro (CIELAB) antes de preparar cavidades esféricas (6 mm de diâmetro, 2 mm de profundidade). As cavidades foram preenchidas aleatoriamente com uma resina composta de única tonalidade (Omnichroma, Diamond One ou Vittra APS Unique) ou com uma resina composta universal (Filtek Universal). Foram realizadas medições das cores das cavidades restauradas e calculadas as diferenças de cor globais (ΔEab and ΔE00)) e as diferenças no índice de clareamento para odontologia (ΔWID) em relação à cor inicial. Além disso, foram realizadas avaliações visuais da correspondência de cor com o esmalte circundante por quarenta avaliadores (leigos e estudantes de odontologia) em uma cabine de visualização sob iluminante D65, com pontuações de 0 (nenhuma discrepância de cor) a 4 (não aceitável). Os dados foram analisados usando RM ou ANOVA unidirecional (α = 0,05). Os resultados mostraram que as restaurações geralmente apresentavam cores mais brancas (WID variou de 27,9 a 41,3) do que os dentes não preparados (WID variou de 15,9 a 19,3). A resina composta Filtek Universal demonstrou a menor discrepância de cor (ΔWID = 8,6; ΔE00 = 10,8; and ΔE00 = 6,2), e não foram observadas diferenças significativas entre as resinas compostas de única tonalidade avaliadas. Além disso, todas as resinas compostas apresentaram correspondência de cor similar e adequada com o esmalte circundante. No entanto, é importante observar que, apesar de sua capacidade de corresponder razoavelmente com o esmalte circundante, nenhuma das resinas compostas avaliadas em grandes restaurações recuperou completamente a cor observada nos dentes não preparados.

Toothbrushing effects on the surface roughness and cement volume loss of bonded enamel-ceramic interface

Abstract This study evaluated the effect of toothbrushing on enamel-cementing material-ceramic bonded interfaces, using different cementing materials. Materials and Methods: Thirty enamel and thirty ceramic blocks were bonded with cementing materials to produce the samples that were bonded with three types of cementing materials: 1- RelyX Ultimate resin cement (REXU), 2- RelyX Unicem 2 self-adhesive resin cement (REU2) and 3- heated Z100 restorative composite (60°C). Bonded interfaces of the samples were toothbrushed and the surfaces of the 3 cementing materials were evaluated for roughness (RG, in µm), roughness profile (RP, in µm), and volume loss (VL, in µm3) (baseline and after 20,000 and 60,000 toothbrushing cycles). Data were evaluated by Generalized Linear Analysis (two factors: "material" and "toothbrushing cycle") and Bonferroni test (α=0.05). Results: REXU and Z100 exhibited lower RG than that presented by REU2, except after 60,000 toothbrushing cycles when only Z100 differed from REU2. The increase in toothbrushing cycles increased the RG and RP for all materials. REU2 also showed higher RP than those showed by REXU and Z100 when it was analyzed regarding the enamel. The VL of Z100 was the lowest with 20,000 toothbrushing cycles, regarding the enamel and ceramic. For 60,000 cycles, REXU showed the lowest VL regarding the ceramic, and REU2 had the highest VL regarding the enamel and ceramic. Conclusion: In general, REXU and Z100 showed the best results regarding the evaluations performed and the REU2 exhibited the highest RG, RP, and VL.

Resumo Este estudo avaliou o efeito da escovação nas interfaces de união esmalte-material cimentante-cerâmica, utilizando diferentes materiais cimentantes. Materiais e Métodos: Trinta esmaltes e trinta blocos cerâmicos foram unidos com materiais de cimentação para produzir as amostras que foram unidas com três tipos de materiais de cimentação: 1- cimento resinoso RelyX Ultimate (REXU), 2- cimento resinoso autoadesivo RelyX Unicem 2 (REU2) e 3-compósito restaurador aquecido Z100 (60°C). As interfaces coladas das amostras foram escovadas e as superfícies dos 3 materiais cimentantes foram avaliadas quanto à rugosidade (RG, em µm), perfil de rugosidade (RP, em µm) e perda de volume (VL, em µm3) (baseline e após 20.000 e 60.000 ciclos de escovação). Os dados foram avaliados por Análise Linear Generalizada (dois fatores: "material" e "ciclo de escovação") e teste de Bonferroni (α=0,05). Resultados: REXU e Z100 apresentaram menor RG do que REU2, exceto após 60.000 ciclos de escovação, quando Z100 diferiu apenas de REU2. O aumento dos ciclos de escovação aumentou o RG e RP para todos os materiais. O REU2 também apresentou PR maior que o REXU e Z100, quando analisado em relação ao esmalte. O VL de Z100 foi o menor com 20.000 ciclos de escovação em relação ao esmalte e cerâmica. Para 60.000 ciclos, o REXU apresentou o menor VL em relação à cerâmica e o REU2 o maior VL em relação ao esmalte e à cerâmica. Conclusão: De maneira geral, REXU e Z100 apresentaram os melhores resultados nas avaliações realizadas e o REU2 apresentou os maiores RG, RP e VL..

Injectable Composite Resin Technique: An Alternative for Anterior Esthetic Restorations - Case Report / Técnica de Resina Compuesta Inyectable: Una Alternativa para Restauraciones Estéticas Anteriores - Reporte de Caso

This article aims to describe a clinical case of the use of the injectable restorative technique with composite resin in a patient with an esthetic complaint in the anterior teeth. Producing direct restorations in anterior teeth when performed with composite resin demands a long clinical time. Results often depend on the operator's ability to reproduce proper form, function, and esthetics. Lately, the versatility of composite resins has increased. As this material evolved, new techniques were introduced to simplify the restorative process and save time. The restorative technique with injectable fluid composite resin, in addition to delivering faster and with a certain ease, is capable of increasing the predictability of treatment results. However, it is known that flowable resins have lower wear resistance and color stability compared to conventional resins. Thus, a version of this material with a higher filler content in its composition was introduced to the market, to improve wear resistance and gloss retention. Long-term studies evaluating the use of low-viscosity resins are needed. The injectable technique can accurately reproduce the morphology obtained in the wax-up of the case, generating a satisfactory esthetic and functional result. Despite simplifying the fabrication of restorations when compared to the conventional technique, it is still necessary for the operator to have some experience and aptitude. The clinical time for the production of restorations has been considerably reduced. The material showed good flow, shine, and polish in the immediate result. However, the finishing and polishing of the restorations required a longer clinical period than usual and in the short- term follow-up, flaws in the gingival margins and a new finishing and polishing procedure were necessary. Therefore, the technique described in this article can be considered a restorative alternative, but it is still not able to replace the tradit ional method of making previous esthetic restorations.

Este artículo tiene como objetivo describir un caso clínico del uso de la técnica restauradora inyectable con resina compuesta en un paciente con una queja estética en los dientes anteriores. Producir restauraciones directas en dientes anteriores cuando se realizan con resina compuesta demanda un largo tiempo clínico. Los resultados a menudo dependen de la capacidad del operador para reproducir la forma, la función y la estética adecuadas. Últimamente, la versatilidad de las resinas compuestas ha aumentado. A medida que este material evolucionó, se introdujeron nuevas técnicas para simplificar el proceso de restauración y ahorrar tiempo. La técnica restauradora con resina compuesta fluida inyectable, además de una entrega más rápida y segura, es capaz de aumentar la previsibilidad de los resultados del tratamiento. Sin embargo, se sabe que las resinas fluidas tienen menor resistencia al desgaste y estabilidad del color en comparación con las resinas convencionales. Así, se introdujo en el mercado una versión de este material con un mayor contenido de relleno en su composición, con el objetivo de mejorar la resistencia al desgaste y la retención del brillo. Se necesitan estudios a largo plazo que evalúen el uso de resinas de baja viscosidad. La técnica inyectable es capaz de reproducir fielmente la morfología obtenida en el encerado del caso, generando un resultado estético y funcional satisfactorio. A pesar de simplificar la fabricación de restauraciones en comparación con la técnica convencional, todavía es necesario que el operador tenga cierta experiencia y aptitud. El tiempo clínico para la producción de restauraciones se ha reducido considerablemente. El material mostró buena fluidez, brillo y pulido en el resultado inmediato. Sin embargo, el acabado y pulido de las restauraciones requirió de un período de tiempo clínico más largo de lo habitual y en el seguimiento a corto plazo, fueron necesarios defectos en los márgenes gingivales y un nuevo procedimiento de acabado y pulido. Por lo tanto, la técnica descrita en este artículo puede considerarse una alternativa restauradora, pero aún no es capaz de reemplazar el método tradicional de realizar restauraciones estéticas previas.

Evaluation of contact angle and mechanical properties of resin monomers filled with graphene oxide nanofibers

Abstract This in vitro study synthesized hybrid nanofibers embedded in graphene oxide (GO) and incorporated them into experimental resin composite monomers to evaluate their physical-mechanical properties. Inorganic-organic hybrid nanofibers were produced with precursor solutions of 1% wt. GO-filled Poly (d,l-lactide, PLA) fibers and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) characterized the morphology and chemical composition of the spun fibers. Resin composite monomers were developed and a total of 5% nanofibers were incorporated into the experimental materials. Three groups were developed: G1 (control resin monomers), G2 (resin monomers/PLA nanofibers), and G3 (resin monomers/inorganic-organic hybrid nanofibers). Contact angle (n=3), flexural strength (n=22), elastic modulus (n=22), and Knoop hardness (n=6) were evaluated. The mean of the three indentations was obtained for each sample. The normality of data was assessed by QQ Plot with simulated envelopes and analyzed by Welch's method (p<0.05). Overall, SEM images showed the regular shape of nanofibers but were non-aligned. Compositional analysis from EDS (n=6) revealed the presence of carbon and oxygen (present in GO composition) and Si from the functionalization process. The results of contact angle (°) and hardness (Kg/mm2) for each group were as follow, respectively: G1 (59.65±2.90; 37.48±1.86a), G2 (67.99±3.93; 50.56±1.03b) and G3 (62.52±7.40; 67.83±1.01c). The group G3 showed the highest Knoop hardness values (67.83 kg/mm2), and the flexural strength of all groups was adversely affected. The experimental resin composite composed of hybrid nanofibers with GO presented increased hardness values and hydrophilic behavior.

Resumo Este estudo in vitro sintetizou nanofibras híbridas embebidas em óxido de grafeno (GO), incorporando-as à uma resina composta experimental de monômeros para avaliar suas propriedades físico-mecânicas. Nanofibras híbridas inorgânica-orgânicas foram produzidas com soluções precursoras de fibras poli (d, l-lactídeo, PLA) preenchidas com GO a 1% em peso e microscopia eletrônica de varredura (MEV) e espectroscopia de raio-X de energia dispersiva (EDS) caracterizaram a morfologia e composição química das fibras. Monômeros de resina composta foram desenvolvidos e um total de 5% de nanofibras foi incorporado aos materiais experimentais. Três grupos foram desenvolvidos: G1 (monômeros de resina controle), G2 (monômeros de resina/ nanofibras de PLA) e G3 (monômeros de resina/nanofibras híbridas inorgânico-orgânicas). Ângulo de contato (n=3), resistência à flexão (n=22), módulo de elasticidade (n=22) e dureza Knoop (n=6) foram avaliados. A média das três endentações foi obtida para cada amostra. A normalidade dos dados foi avaliada pelo QQ Plot com envelopes simulados e analisada pelo método de Welch (p<0,05). No geral, as imagens de MEV mostraram forma regular de nanofibras, mas não alinhadas. A análise composicional de EDS (n=6) revelou a presença de carbono e oxigênio (presentes na composição do GO) e Si resultante do processo de funcionalização. Os resultados do ângulo de contato (°) e dureza (Kg/mm2) para cada grupo foram os seguintes, respectivamente: G1 (59,65±2,90; 37,48±1,86a), G2 (67,99±3,93; 50,56±1,03b) e G3 (62,52±7,40; 67,83±1,01c). G3 apresentou os maiores valores de dureza Knoop (67,83 kg/mm2), e a resistência à flexão de todos os grupos foi prejudicada. A resina composta experimental composta por nanofibras híbridas com GO apresentou maiores valores de dureza e comportamento hidrofílico.

Surface Analysis of a Universal Resin Composite and Effect of Preheating on its Physicochemical Properties

Abstract This study was aimed at analyzing the surface properties of a universal resin composite and evaluating the effect of preheating on its physicochemical properties. Two commercial resin composites were used under two conditions: Filtek Universal Restorative (UR); UR preheated (URH); Filtek Supreme (FS) and FS preheated (FSH). The film thickness (FT) test (n = 10) was done using two glass slabs under compression. Flexural strength (FLS) and modulus (FLM) were evaluated using a three-point flexion test (n = 10). Polymerization shrinkage stress (PSS) was evaluated in a universal testing machine (n = 5). Gap width (GW) between composite and mold was measured in internally polished metallic molds (n = 10). The degree of conversion (DC) was evaluated by Fourier Transform Infrared spectroscopy (n = 3). The morphology of the filler particles was checked by scanning electron microscope (SEM) and EDX analysis. Surface gloss (SG) and surface roughness (SR) were evaluated before and after mechanical brushing (n = 10). The outcomes were submitted to 2-way ANOVA and Tukey's test (α = 0.05). Lower mean values of FT were observed for the preheated groups when compared to the non-preheated groups. URH and FSH showed higher mean values of FLS and FLM when compared with UR and FS. No differences were observed between groups in the PSS test. The GW was higher for the UR and FS groups when compared with URH and FSH. The DC was higher for preheated resin composites when compared to the non-preheated groups. The SR of the UR composite was higher than the FS after mechanical brushing, while the SG was higher for the FS groups. In conclusion, the universal resin composite tested generally presented similar physicochemical properties compared with the nanofilled resin composite and either similar or slightly inferior surface properties. The preheating improved or maintained all properties evaluated.

Resumo Neste estudo avaliou-se propriedades físico-químicas e de superfície de um compósito universal pré-aquecido e comparado a um compósito convencional. Foram utilizados dois compósitos comerciais: Filtek Universal Restorative (UR); UR pré-aquecido (URH); Filtek Supreme (FS) e FS pré-aquecido (FSH). O teste de espessura de película (EP) (n = 10) foi feito usando duas placas de vidro sob compressão. A resistência à flexão (RF) e o módulo flexural (MF) foram avaliados por meio do teste de flexão de três pontos (n = 10). A tensão de contração de polimerização (TCP) foi avaliada em uma máquina de teste universal (n = 8). A largura da fenda (LF) entre o compósito e o molde foi medida em moldes metálicos polidos internamente (n = 10). O grau de conversão (GC) foi avaliado por espectroscopia de infravermelho com transformada de Fourier (n = 3). A morfologia das partículas de carga foi observada em microscopia eletrônica de varredura (MEV) e sua composição em EDX. Brilho superficial (BS) e rugosidade superficial (RS) foram avaliados antes e após escovação mecânica (n=10). Os resultados foram submetidos à ANOVA 2-fatores e as médias comparadas pelo teste de Tukey (α = 0,05). Menores valores médios de EP foram observados para os grupos pré-aquecidos quando comparados aos grupos não pré-aquecidos. URH e FSH apresentaram maiores valores médios de RF e MF quando comparados com UR e FS. Não foram observadas diferenças entre os grupos no teste TCP. A LF foi maior para os grupos UR e FS quando comparados com URH e FSH. O GC foi maior para os compósitos pré-aquecidos quando comparados aos não pré-aquecidos. A RS do compósito UR foi maior que o FS após a escovação mecânica, enquanto o BS foi maior para os grupos FS. Em conclusão, o compósito universal testado geralmente apresentou propriedades físico-químicas semelhantes em comparação ao compósito nanoparticulado e propriedades de superfície semelhantes ou ligeiramente inferiores. O pré-aquecimento melhorou ou manteve todas as propriedades avaliadas.

Effect of elastomeric urethane monomer on physicochemical properties and shrinkage stress of resin composites

Abstract This study aimed to evaluate the effect of an elastomeric urethane monomer (Exothane-24) in different concentrations on physicochemical properties, gap formation, and polymerization shrinkage stress of experimental resin composites. All experimental composites were prepared with 50 wt.% of Bis-GMA and 50 wt.% of TEGDMA, to which 0 wt.% (control), 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.% of Exothane-24 were added. Filler particles (65 wt.%) were then added to these resin matrixes. Ultimate tensile strength (UTS: n = 10), flexural strength (FS: n = 10), flexural modulus (FM: n = 10), hardness (H: n = 10), hardness reduction (HR: n = 10), degree of conversion (DC: n = 5), gap width (GW: n = 10), and polymerization shrinkage stress in Class I (SS-I: n = 10) and Class II (SS-II: n = 10) simulated configuration. All test data were analyzed using one-way ANOVA and Tukey's test (α = 0.05; β= 0.2). Exothane-24 in all concentrations decreased the H, HR, DC, GW, SS-I, and SS-II (p < 0.05) without affecting the UTS, and FS (p > 0.05). Reduction in FM was observed only in the Exothane 40% and 30% groups compared to the control (p < 0.05). Exothane-24 at concentrations 20% and 30% seems suitable since it reduced GW and polymerization SS without affecting the properties of the composite resins tested, except for H.

Resumo Este estudo teve como objetivo avaliar o efeito de um monômero elastomérico de uretano (Exothane-24) em diferentes concentrações em propriedades físico-químicas, formação de fenda e tensão de contração de polimerização de resinas compostas experimentais. Todos os compósitos experimentais foram preparados com 50% em peso de Bis-GMA e 50% em peso de TEGDMA, nos quais 0% (controle), 10%, 20%, 30% e 40% em peso de Exothane-24 foram adicionados. Partículas de carga (65% em peso) foram então adicionadas as matrizes resinosas. Resistência coesiva (RC: n = 10), resistência à flexão (RF: n = 10), módulo de flexão (MF: n = 10), dureza (D: n = 10), redução de dureza (RD: n = 10), grau de conversão (GC: n = 5), largura de fenda (LF: n = 10) e tensão de contração de polimerização em simulações de cavidades Classe I (TC-I: n = 10) e Classe II (TC-II: n = 10). Todos os dados do teste foram analisados usando one-way ANOVA e teste de Tukey (α = 0,05; β = 0,2). O Exothane-24 em todas as concentrações diminuiu a D, RD, GC, LF, TC-I e TC-II (p < 0,05) sem afetar o RC e RF (p > 0,05). A redução da MF foi observada apenas nos grupos Exothane 40% e 30% em relação ao controle (p < 0,05). O Exothane-24 nas concentrações de 20% e 30% pareceu ser adequado, pois reduziu LF e TC de polimerização sem afetar as propriedades das resinas compostas testadas, exceto para D.

Depth of cure, mechanical properties and morphology of dual-cure bulk-Fill composites / Profundidad de curado, propiedades mecánicas y morfología de resinas compuestas duales

This study evaluated selected structural and physical properties, such as degree of conversion (DC), Vickers hardness (VHN), and compression strength (CS), of three new dual-cure bulk-fill resin-based composites (RBCs; ACTIVA, HyperFIL, and Fill-Up) and compared them to those of a conventional RBC (Filtek Z250) at three clinically relevant depths. Samples (n=180) were prepared in three depths (2,4, and 6mm). Fourier-transform infrared spectroscopy (FTIR) analysis and VHN and CS tests were performed. The DC value was calculated by considering the relative change in the aliphatic C=C peaks. The fractured surfaces of representative samples were characterized using scanning electron microscopy (SEM). Data were statistically evaluated using two-way analysis of variance and post hoc Bonferroni tests (p<0.05). According to the VHN results, Filtek Z250 showed the highest bottom/top hardness ratio (97.94±1.01) at 2mm thickness and ACTIVA showed the lowest bottom/top hardness ratio (43.48±5.64) at 6mm thickness (p<0.001). According to the FTIR results, the DC decreased with increasing thickness in all materials (p<0.05). Filtek Z250 showed the highest (301±12.4 MPa) and ACTIVA exhibited the lowest (232±17.2 MPa) CS values at 2mm thickness (p<0.05). The lowest CS values were obtained for ACTIVA, and the highest values were obtained for Filtek Z250 for samples with thicknesses of 4 and 6mm, respectively (p<0.05). The structural features of restorative composites, such as the resin chemistry and filler type and content, and the operational parameters (i.e., material thickness and curing conditions) strongly affect crosslinking reactions and thus the DC, VHN, and CS values.

Este estudio evaluó propiedades físicas y estructurales, como el grado de conversión (DC), la dureza Vickers (VHN) y la resistencia a la compresión (CS), de tres nuevos compósitos a base de resina de curado dual tipo bulk (RBC; ACTIVA , HyperFIL y Fill-Up) y los comparó con los de una resina compuesta convencional (Filtek Z250) en tres profundidades clínicamente relevantes. Se prepararon muestras (n=180) en tres profundidades (2,4 y 6mm). Se realizaron análisis de espectroscopia infrarroja por transformada de Fourier (FTIR) y pruebas VHN y CS. El valor de DC se calculó considerando el cambio relativo en los picos alifáticos C=C. Las superficies fracturadas de muestras representativas se caracterizaron mediante microscopía electrónica de barrido (MEB). Los datos se evaluaron estadísticamente mediante análisis de varianza de dos vías y pruebas post hoc de Bonferroni (p<0,05). De acuerdo con los resultados de VHN, Filtek Z250 mostró la relación de dureza inferior/superior más alta (97,94±1,01) con un espesor de 2mm y ACTIVA mostró la relación de dureza inferior/superior más baja (43,48±5,64) con un espesor de 6mm (p<0,001). De acuerdo con los resultados de FTIR, la DC disminuyó al aumentar el espesor en todos los materiales (p<0,05). Filtek Z250 mostró los valores de CS más altos (301±12,4 MPa) y ACTIVA los más bajos (232±17,2 MPa) a 2mm de espesor (p<0,05). Los valores más bajos de CS se obtuvieron para ACTIVA y los valores más altos para Filtek Z250 para muestras con espesores de 4 y 6mm, respectivamente (p<0,05). Las características estructurales de las resinas compuestas de restauración, como la química; además del tipo y contenido del relleno, y los parámetros operativos (es decir, el espesor del material y las condiciones de curado) afectan en gran medida las reacciones de interacción química y, por lo tanto, los valores de DC, VHN y CS.

Microtensile bond strength of resin composite to dentin using different adhesive systems and directions of electric current

Resumo O objetivo neste estudo foi avaliar o efeito da direção da corrente elétrica na resistência da união resina composta-dentina usando três sistemas adesivos. Dentes molares humanos foram distribuídos de acordo com o sistema adesivo (dois passos autocondicionante - Clearfil SE Bond, Kuraray [CSE]; e um passo autocondicionante - Single Bond Universal, 3M ESPE [SBU]; e dois passos convencional - Adper Single Bond 2, 3M ESPE [SB2]), a direção da corrente elétrica (sem corrente elétrica - controle, correntes elétricas direta e reversa - 35µA) e tempo de armazenamento (24h - imediato e 6 meses). Blocos de resina composta (Filtek Z350XT, 3M ESPE) foram aderidos à dentina. Amostras de dentina-resina foram produzidas e armazenadas em água destilada a 37ºC por 24 horas e 6 meses para o teste de resistência da união à microtração (µTBS) (n = 10; ~12 palitos por dente). Os padrões de fratura foram analisados ​​em estereomicroscópio e classificados em falhas coesiva na dentina, coesiva na resina, adesiva ou mista. A penetração do adesivo na dentina e a formação da camada híbrida foram avaliadas em microscópio eletrônico de varredura (MEV). Os dados foram submetidos à ANOVA três fatores seguidos pelo teste post hoc de Tukey (α = 0,05). Não houve diferenças na µTBS quando os sistemas adesivos foram aplicados sob as correntes elétricas direta e reversa, mas ambas as correntes elétricas aumentaram a µTBS para todos os sistemas adesivos. SBU apresentou os menores valores de µTBS para o grupo controle em ambos os tempos de armazenamento e para a corrente elétrica direta em 6 meses de armazenamento. Falhas adesivas foram mais frequente em todos os grupos. A corrente elétrica formou longos tags resinosos para todos os sistemas adesivos. O armazenamento por 6 meses não diminuiu significativamente os valores de µTBS. Ambos os sentidos da corrente elétrica (cargas positivas e negativas) a 35µA podem aumentar a µTBS dos sistemas adesivos testados à dentina.

Abstract Thisstudy aimed to evaluate the effect of the electric current direction application on the resin composite-dentin bond strength using three adhesive systems. Human molar teeth were distributed according to the adhesive system (two-step self-etch - Clearfil SE Bond, Kuraray [CSE]; one-step self-etch - Single Bond Universal, 3M ESPE [SBU]; and two-step etch-and-rinse - Adper Single Bond 2, 3M ESPE [SB2]), electric current direction (without electric current - control, direct and reverse electric currents - 35µA), and storage time (24h - immediate and 6 months). Resin composite blocks (Filtek Z350XT, 3M ESPE) were bonded to dentin. The teeth/resin composites specimens were stored in distilled water at 37ºC for 24 hours and 6 months for the microtensile bond strength (µTBS) test (n = 10; ~12 sticks for each tooth). Failure patterns were analyzed on a stereomicroscope and classified as cohesive-dentin, cohesive-resin, adhesive or mixed. Adhesive penetration into dentin and hybrid layer formation were evaluated in a scanning electron microscope (n = 6). Data were submitted to a three-way ANOVA followed by Tukey's post hoc test (α = 0.05). There are no differences in µTBS when the adhesive systems were applied under direct and reverse electric currents, but both electric currents increased the µTBS for all adhesive systems. SBU showed the lowest µTBS values for control groups in both storage times and direct electric current in 6 months of storage. The adhesive failure pattern was more frequently observed in all groups. The electric current formed long resin tags for all adhesive systems. Storage for 6 months did not significantly decrease µTBS values. Both directions of electric current (positive and negative charges) at 35µA can increase the µTBS of the adhesive systems tested to dentin.

Effect of surrounded shade and specimen`s thickness on color adjustment potential of a single-shade composite

Abstract This study evaluated the effect of surrounded shade and specimens` thickness on the color adjustment potential (CAP) of a single-shade composite. The composite Vittra APS Unique was surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens of the control composite were also confectioned. Opacity and whiteness index for dentistry (WID) were calculated for simple specimens. Color differences between the simple (ΔE*SIMPLE)/ dual specimens (ΔE*DUAL) and the controls were calculated. CAP was calculated based on the ratio between ΔE* SIMPLE and ΔE* DUAL. The tested composite presented lower opacity (53 to 62% vs. 80 to 93%) and higher WID (≈ 42 vs. 18 to 32) than controls. Irrespective of the specimens' thickness (1.0/ 1.5 mm), the lowest values of ΔE* SIMPLE (11.1/ 10.8) and ΔE*DUAL (7.2/ 6.1) were observed using the surrounding shade A1. The shade A3 yielded higher ΔE*SIMPLE (16.4/ 17.1) and ΔE* DUAL (11.3/ 12.3) than the A2 (ΔE*SIMPLE = 13.4/ 14.6; and ΔE* DUAL = 9.7/ 10.3). The specimen`s thickness significantly affected the CAP (0.35 and 0.44 for 1.0 and 1.5 mm, respectively) only for shade A1, which had the highest CAP values. The shade A3 resulted in higher CAP values (0.31) than A2 (0.27) when 1.0-mm thick specimens were used, but similar values were observed for 1.5 thick specimens (≈ 0.29). In conclusion, both surrounding shade and specimen thickness can affect the CAP of a single-shade resin composite.

Resumo Este estudo avaliou o efeito da cor circundante e da espessura da amostra no potencial de ajuste de cor (PAC) de uma resina monocromática. O compósito Vittra APS Unique foi circundado (amostras duplas) ou não (amostras simples) com um compósito controle (cor A1, A2 ou A3). Amostras simples do compósito controle também foram confeccionadas. A opacidade e o índice de brancura para odontologia (IBO) foram calculados para as amostras simples. As diferenças de cor entre amostras simples (ΔE*SIMPLE) / duplas (ΔE*DUAL) e os controles foram calculados. PAC foi calculado baseado na razão entre ΔE* SIMPLE e ΔE* DUAL. O compósito testado apresentou menor opacidade (53 a 62% vs. 80 a 93%) e maior IBO (≈ 42 vs. 18 a 32) que os controles. Independente da espessura da amostra (1,0/ 1,5 mm), os valores mais baixos de ΔE* SIMPLE (11,1/ 10,8) e ΔE*DUAL (7,2/ 6,1) foram observadas quando a resina circundante era A1. A cor A3 resultou em maior ΔE*SIMPLE (16,4/ 17,1) e ΔE* DUAL (11,3/ 12,3) do que A2 (ΔE*SIMPLE = 13,4/ 14,6; e ΔE* DUAL = 9,7/ 10,3). A espessura das amostras afetou significativamente o PAC (0,35 e 0,44 para 1,0 e 1,5 mm, respectivamente) apenas para a cor A1, que teve os maiores valores de PAC. A cor A3 resultou nos maiores valores de PAC (0,31) que A2 (0,27) quando amostras de 1,0 mm de espessura foram usadas, mas valores similares foram observados para amostras de 1,5 mm (≈ 0,29). Como conclusão, tanto a cor circundante como a espessura das amostras podem afetar o PAC de um compósito resinoso monocromático.

linical performance of one shade universal composite resin and nanohybrid composite resin as full coronal esthetic restorations in primary maxillary incisors A randomized controlled trial

Background: Strip crowns are the first treatment of choice for restoring anterior teeth affected with early childhood caries. However, shade matching of resin composites is still an issue. The broad color matching ability of a recently introduced single shade composite, Omnichroma eliminates the need for shade-matching procedure, reduces composite inventory, and minimizes chair-side time. Aim: The aim is to evaluate the color match, color stability, and retention of one shade universal composite resin, Omnichroma and nanohybrid resin composite, Tetric-N-Ceram. Settings and Design: The study design involves split-mouth randomized controlled trial. Materials and Methods: The study was conducted on 25 children aged 3–5 years with multi-surface caries lesions in primary maxillary anterior teeth. Teeth were allocated to two groups randomly: Group 1 – One shade universal composite, Omnichroma (n = 25), Group 2 – Nanohybrid composite, Tetric-N-Ceram (n = 25). After caries excavation and tooth preparation, teeth were restored with corresponding materials using strip crowns. Color match at baseline, color stability, and retention after 6- and 12-month follow-up were evaluated using the Modified United States Public Health Services criteria. Statistical Analysis: The Mann–Whitney U test and Wilcoxon signed-rank test were used to analyze the data. Results: On comparison of Omnichroma and Tetric-N-Ceram groups, no statistically significant difference was observed in the color match at baseline (P = 0.716) as well as color stability (P = 0.575 at 6 months and 0.990 at 12 months) and retention (P = 0.153 at 6 months and 0.226 at 12 months) at both 6- and 12-month intervals. On intragroup comparison, the difference in the color stability at 6 and 12-month interval was statistically significant (P = 0.001) for both the groups, indicating that the color stability of restorations was better at 6-month interval compared to 12-month interval. In both Omnichroma and Tetric-N-Ceram groups, retention of restorations was better at 6-month interval compared to 12-month interval and this difference was statistically significant (P = 0.025 and 0.014, respectively). Conclusion: The clinical performance of Omnichroma in terms of color match, color stability, and retention was comparable to nanohybrid composite, Tetric-N-Ceram.

Violet LED-Based Tooth Whitening and Resin Composite Restorations to Reestablish Smile Aesthetics Case Report

ABSTRACT: This clinical case described the aesthetic treatment of a patient complaining about the aspect of their upper teeth. After anamnesis and clinical examination, the association of tooth whitening photoactivated by violet LED and resin composite restorations was indicated. Prior to restorative treatment, three bleaching sessions were performed with low concentration hydrogen peroxide (6 %; Nano white flex) for 30 minutes. During this period, violet LED irradiation was intercalating performed every 1 minute, totalizing 15 minutes. Ten days after the final bleaching session, old restorations in the upper lateral incisors were removed for better color selection of resin composites. Then, all upper anterior teeth were directly restored with nanofilled resin composite (Filtek Z350XT), reestablishing anatomy, form, and function. At the end of the treatment, the association of techniques proved to be cost-effective, restoring the esthetics satisfactorily and promoting the patient's well-being by a minimally invasive approach.

RESUMEN: En este reporte de caso se describió el tratamiento para una paciente que se quejaba del aspecto de sus dientes superiores. Tras anamnesis y exploración clínica, se indicó la asociación de blanqueamiento dental fotoactivado por LED violeta y restauraciones de resina compuesta. Antes del tratamiento restaurador, se realizaron tres sesiones de blanqueamiento con peróxido de hidrógeno de baja concentración (6 %; Nano white flex) durante 30 minutos. Durante este período, la irradiación con LED violeta se intercalaba cada 1 minuto, totalizando 15 minutos. Diez días después de la última sesión de blanqueamiento, se retiraron las restauraciones antiguas de los incisivos laterales superiores para una mejor selección del color de la resina compuesta. Luego, todos los dientes anteriores superiores fueron restaurados de manera directa con resina de nanorrelleno (Filtek Z350XT), restableciendo la anatomía, forma y función. Al final del tratamiento, la asociación de las técnicas resultó beneficioso, restaurando la estética de forma satisfactoria y promoviendo el bienestar de la paciente mediante un abordaje mínimamente invasivo.

Restauración clase II MOD mediante uso de resina bulk-fill fluida y resina de estratificación natural: combinando fortalezas en una preparación extensa / Class II MOD restoration using bulk-fill flowable and natural layering resin composites: combining strengths in an extensive preparation

RESUMEN La restauración de grandes preparaciones cavitarias clases II MOD es un escenario clínico de alta complejidad. Elegir correctamente una resina compuesta y planificar la secuencia de estratificación permitirá mejorar la adaptación de las masas de resina y controlar el estrés de contracción de polimerización. En el siguiente reporte de caso clínico, se expone el protocolo paso a paso para el uso combinado de una resina compuesta para estratificación de esmalte de alto índice de refracción para la restauración de los rebordes marginales perdidos y la superficie oclusal, junto a una resina compuesta bulk-fill de baja viscosidad para la reconstrucción dentinaria en un diente posterior con gran destrucción coronaria.

ABSTRACT The restoration of large class II MOD cavity preparations is a highly complex clinical scenario. Selecting correctly a composite resin and planning the stratification sequence will improve the adaptation of the composite resin masses and will control the polymerization shrinkage stress. In the following clinical case report, the step- by-step protocol of the combined use of an high-refractive-index enamel-like composite resin is shown for the restoration of lost marginal ridges and the occlusal surface, together with a low viscosity Bulk-Fill composite resin for dentine reconstruction in a highly damaged posterior tooth.

The effect of storage temperature and application temperature on the properties of adhesives and resin composites / 口腔疾病防治

@#The properties of adhesives and light-cured resin composites are closely related to the repair of dental defects. Therefore, improving the properties of adhesives and resins composite to increase the success rate of filling has been the focus of research in the field of prosthodontics in recent years. Current studies have confirmed that temperature can change the properties of adhesives and light-cured resin composites, affecting their repair effect. A proper storage temperature ensures the good performance of materials: the self-etching adhesive system should be refrigerated, and the light-cured resin composite should be refrigerated or stored at room temperature according to its composition, proportion and other properties; however, the appropriate storage temperature for the etch-and-rinse adhesive system is not clear. The appropriate application temperature could improve the fluidity, monomer conversion, bonding strength, compressive strength and other properties of the materials to improve the quality of filling restoration. However, there is a wide variety of adhesives and resin composites, and the effect of temperature on each material is different. Thus, it is still necessary to explore the temperature range for material storage, precooling and preheating. Few studies have been performed in vivo, and the clinical restorative effects of adhesives and resin composites stored and used at different temperatures need to be further studied.

A influência da sorção e solubilidade nas propriedades dos compósitos resinosos: uma revisão de literatura / The influence of sorption and solubility on the properties of res-in composites: a literature review

Introdução: A resina composta tem sido amplamente utilizada por suas propriedades restauradoras. No entanto, quando exposta à água, o material resinoso sofre diferentes mecanismos químicos e físicos, como a sorção de água e solubilidade. Esses efeitos podem produzir alterações volumétricas e mudanças físicas, alterando as características do material. Objetivo: Discorrer acerca das consequências clínicas dos fenômenos de sorção e solubilidade na resina composta. Materiais e Métodos: Uma revisão da literatura foi realizada por meio de artigos científicos publicados nos últimos anos, presentes em bases de dados eletrônicos como PubMED/Medline, Lilacs e Scielo. Resultados e Discussão: Os compósitos de resina não são estáveis, pois interagem constantemente com o ambiente oral. Sua principal interação é com água, que se difunde na matriz. As resinas compostas que contêm, além do BIS-GMA, uma alta concentração de TEGDMA, tendem a absorver mais água devido às ligações éter hidrofílicas presentes nesses compósitos. Com isso, uma série de efeitos deletérios podem ocorrer. Conclusão: A expansão volumétrica, a lixiviação, a degradação hidrolítica e a instabilidade da cor são as principais consequências da sorção e solubilidade da resina composta. Esses fenômenos provocam alterações dimensionais e diminuição das propriedades mecânicas repercutindo, sobremaneira, na longevidade das restaurações em resina composta.

Introduction: Resin Composite has been widely used for its restorative properties. However, when exposed to water, the resin material undergoes different chemical and physical mechanisms, such as water sorption and solubility. These effects can produce volumetric and physical changes, altering the material's characteristics. Objective: To discuss the clinical consequences of the sorption and solubility phenomena in composite resin. Materials and Methods: A literature review was performed using scientific articles published in recent years on electronic databases such as PubMED/Medline, Lilacs, and Scielo. Results and Discussion: Resin composites are not stable, as they constantly interact with the oral environment. Their main interaction is with water, which diffuses into the matrix. Resin Composites that contain, in addition to BIS-GMA, a high concentration of TEGDMA, tend to absorb more water due to the hydrophilic ether bonds present in these composites. Thus, a series of deleterious effects can occur. Conclusion: Volumetric expansion, leaching, hydrolytic degradation, and color instability are the main consequences of Resin Composite sorption and solubility. These phenomena cause dimensional changes and a decrease in mechanical properties, which have a major impact on the longevity of Resin Composite restorations.

Effect of whitening mouthrinses on color change of stained resin composites / Efeito de enxaguatórios clareadores na alteração de cor de resinas compostas previamente manchadas

Objective: The present study compared the effect of whitening mouthrinses (WM) on the color change of stained resin composites (RC). Material and Methods: Cylindrical specimens (6mm-diameter and 1mm-thickness) were prepared with the following RC (n=60/group): Filtek Z350XT (Z350- methacrylate-based), Admira Fusion (AD- ormocer-based), TPH3 (TPH- methacrylate-based), and Beautifil II (BII- giomer/methacrylate-based). The initial color was assessed with reflectance spectrophotometer using CIE L*a*b* system. The specimens were immersed in staining broth during 14 days, submitted to color evaluation (ΔE1) and randomly allocated in 4 subgroups (n=15), according to WM adopted: Listerine Whitening (LW-2% hydrogen peroxide), Plax Whitening (PW-1.5% hydrogen peroxide), Bromelain/papain (BP-experimental solution), and Deionized water (DW-negative control). The whitening cycle consisted of RC immersion in WM for 1 min and in artificial saliva for 30 min, simulating 12 weeks, and final color assessment was performed (ΔE2). Color change data were analysed by ANOVA and Tukey's tests (α=5%). Results: After staining, TPH showed the lowest ΔE1 values and Z350 showed the highest color change (p=0.001). The whitening effect promoted by LW was significantly higher than color alteration obtained with PW (ΔE2), and BII showed the highest color change values (ΔE2) after whitening cycle. Conclusion: LW exhibited the greatest whitening potential on stained RC, mainly with the Giomer (Beautifill II) and the Ormocer-based (Admira Fusion) materials. Bromelain/papain solution showed no whitening effect on stained RC. (AU)

Objetivo: O presente estudo comparou o efeito de enxaguatórios clareadores (EC) na alteração de cor de resinas compostas (RC) previamente manchadas. Material e Métodos: Espécimes cilíndricos (6mm de diâmetro e 1mm de espessura) foram preparados com as seguintes RC (n=60/grupo): Filtek Z350XT (Z350- metacrilato), Admira Fusion (AD- ormocer), TPH3 (TPH- metacrilato), e Beautifil II (BII- giomer/metacrilato). A cor inicial foi mensurada com espectrofotômetro de reflectância utilizando o sistema CIE L*a*b*. Os espécimes foram imersos em um caldo de manchamento durante 14 dias, submetidos a avaliação de cor (ΔE1) e alocados aleatoriamente em 4 subgrupos (n=15), de acordo com EC adotado: Listerine Whitening (LW-peróxido de hidrogênio a 2%), Plax Whitening (PW- peróxido de hidrogênio a 1,5%), Bromelina/papaína (BP-solução experimental), e Água deionizada (AD- controle negativo). O ciclo clareador consistiu na imersão da RC no EC por 1 min e na saliva artificial por 30 min, simulando 12 semanas, e a cor final foi mensurada (ΔE2). Os dados de alteração de cor foram analisados pelos testes ANOVA e Tukey (α=5%). Resultados: Após o manchamento, TPH apresentou o menor valor de ΔE1 e Z350 apresentou a maior alteração de cor (p=0,001). O efeito clareador promovido pelo LW foi significativamente maior que o obtido com o PW (ΔE2) e BII teve a maior alteração de cor (ΔE2) após o ciclo clareador. Conclusão: LW exibiu maior potencial clareador nas RC manchadas. BII apresentou maior alteração de cor em resposta à ação clareadora de ambos enxaguatórios à base de peróxido de hidrogênio testados.(AU)

Effect of handpiece light and material used in pulp chamber on dentin removal during root canal retreatment

Abstract This study evaluated the effect of the use of glass ionomer cement (GIC) and flowable bulk-fill resin composite (BFRC) for filling pulp chambers and the type of high-speed handpiece light used on dentin removal during access preparation for endodontic retreatment in molar teeth. Twenty maxillary molars were treated endodontically. BFRC (Opus Bulk Fill Flow APS, FGM) was used to fill the pulp chamber and replace coronal dentin (n = 10). In the remaining teeth, the pulp chamber was filled with GIC (Maxion R, FGM). Conventional resin composite (Opallis, FGM) was used to restore the enamel layer in all teeth. The samples in each group were divided into two subgroups, and the root canals were reaccessed using a handpiece with white or ultraviolet light. The teeth were scanned using micro-CT before and after root canal reaccess. The dentin volume removed was calculated and analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). The crown and pulp chamber locations with dentin removal are described using frequency distribution. During the access, fewer pulp chamber walls were affected and a lower volume of dentin was removed from the pulpal floor in the group restored with GIC than in the group restored with BFRC. No effect was observed on the coronal dentin walls with respect to the filling protocols and type of light used. For dentin removal from the pulp chamber, handpieces with white light performed better than those with ultraviolet light, irrespective of the filling protocol used. The use of GIC to fill the pulp chamber and use of white handpiece light reduced dentin removal from the pulpal floor and resulted in fewer affected dentin walls.

Resumo Este estudo avaliou os efeitos do cimento de ionômero de vidro (GIC) e da resina composta fluida bulk fill (BFRC) usados como preenchimento da câmara pulpar; e o tipo de iluminação das turbinas de alta rotação na remoção dentinária após cavidades de acesso para retratamento endodôntico em dentes molares. Vinte molares superiores foram tratados endodonticamente. Dez dentes foram restaurados usando BFRC (Opus Bulk Fill Flow APS, FGM) para preencher a câmara pulpar e dentina coronária; e resina composta convencional (Opallis, FGM) para restaurar a camada de esmalte. Os outros dentes foram restaurados usando GIC (Maxion R, FGM) para preencher a câmara pulpar e resina composta (Opallis, FGM). As amostras foram divididas em dois grupos e os canais radiculares foram novamente acessados com turbina de alta-rotação com iluminação branca ou ultravioleta. Os dentes foram escaneados usando micro-CT antes e após o novo acesso ao canal radicular. O volume de dentina removida foi calculado e os dados foram analisados por ANOVA bidirecional e teste de Tukey (α=0,05). As regiões na coroa e na câmara pulpar que apresentaram dentina removida no acesso dos canais foram descritas por meio de distribuição por frequência. A reabertura do canal radicular com GIC resultou em menos paredes afetadas da câmara pulpar e menor volume de dentina removida no assoalho. Nenhum efeito foi observado nas paredes de dentina coronária considerando aos protocolos de preenchimento. A turbina de alta rotação com iluminação branca reduziu a remoção de dentina da câmara pulpar, independentemente do protocolo de restauração utilizado. O uso de turbina de alta rotação com iluminação branca e GIC para preencher a câmara pulpar reduziram a remoção de dentina do assoalho e afetaram menos paredes dentinárias.

The effect of acid concentration and etch time on morphology and tensile bond strength of primary dentin An in vitro study

Background: There are conflicting results concerning the ideal time for etching primary dentin and its effect on the bond strength of adhesive restorative materials. Aim: To assess in vitro, the effect of varied acid concentration and etch time on the morphological features and tensile bond strength of primary dentin. Materials and Methods: Forty healthy primary molars were prepared by exposing the dentin of the occlusal surface, creating a smear layer. A 3 mm × 3 mm test indow was demarcated, and specimens were randomly allocated to four groups (n = 10): Group 1A 10% phosphoric acid, 7 s; Group 1B 10% phosphoric acid, 15 s; Group 2A 37% phosphoric acid, 7 s and Group 2B 37% phosphoric acid, 15 s. Surface analysis was done using atomic force microscope and scanning electron microscope. For tensile bond strength evaluation, 24 specimens prepared as mentioned were mounted in acrylic blocks and allocated to four groups according to the prescribed etching protocol. Resin rods were bonded and tested in tension after 24 h (n = 6). Data were analyzed statistically using unpaired t-test. Results: Etching of primary dentin using 37% phosphoric acid for 7 s produced the highest tensile bond strength of 9.51 ± 2.19 MPa. Conclusion: Etching time of 7 s may improve the adhesion of resin restorative materials with primary dentin.

Microhardness homogeneity of RBCs light-cured with a multiple-peak LED and surface characterization after wear

Abstract This in vitro study evaluated the effect of the beam homogeneity of a multiple-peak light-curing unit on the surface microhardness and the effect of toothbrushing wear on the microhardness, surface roughness, roughness profile, volume loss, and gloss retention of incremental and bulk-fill resin-based composites (RBCs). A LED light-curing unit (VALO) with four LEDs at the tip end (405, 445, 465A, and 465B nm emission peak) was used according to each manufacturer-recommended time to obtain disks (n=10) of six RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra, and Filtek Bulk Fill. Microhardness values were obtained according to each LED positioning of the light-curing unit on the top surface of the RBCs and were analyzed before and after toothbrushing regarding microhardness, surface roughness, roughness profile, volume loss, and gloss retention. Microhardness was considered homogeneous on the top surface regardless of the type of RBC or wavelength tested (p>0.05). Overall, toothbrushing did not reduce the microhardness of the RBCs but influenced the gloss values for most RBCs (p<0.001). Charisma Classic presented the greatest surface roughness and roughness profile after toothbrushing (p<0.05). Volume loss did not differ among RBCs (p>0.05). In conclusion, different wavelengths of the LED did not affect the top surface microhardness, regardless of the RBCs tested; and bulk-fill composites presented similar surface changes (microhardness, surface roughness, roughness profile, volume loss, and gloss retention) when compared to conventional composites after toothbrushing.

Resumo Este estudo in vitro avaliou a homogeneidade do feixe de um fotopolimerizador de múltiplos picos na microdureza superficial e o efeito da escovação na microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho de compósitos a base de resina (RBCs) incrementais ou bulk-fill. Um fotopolimerizador LED (VALO) com quatro LEDs na ponteira (405, 445, 465A e 465B nm de pico de emissão) foi usado de acordo com o tempo recomendado por cada fabricante para obtenção de discos (n=10) de seis RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra e Filtek Bulk Fill. Os valores de microdureza foram obtidos seguindo o posicionamento de cada LED na superfície superior das amostras e foram analisados antes e após a escovação quanto a microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho. A microdureza foi considerada homogênea no topo da superfície, independentemente do tipo de RBCs ou comprimento de onda testados (p>0.05). No geral, a escovação não reduziu a microdureza das RBCs, mas influenciou o brilho para a maioria das RBCs (p<0.001). Charisma Classic apresentou os maiores valores de rugosidade superficial e perfil de rugosidade após a escovação (p<0.05). A perda de volume não diferiu entre as RBCs (p>0.05). Em conclusão, os diferentes comprimentos de onda do LED não alteraram a microdureza do topo da superfície, independentemente das RBCs testadas; e as resinas bulk-fill apresentaram alterações superficiais similares (microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e manutenção do brilho) quando comparadas às resinas convencionais após a escovação.

Effect of Light Sources on Bond Strength of Different Composite Resins Repaired with Bulk-Fill Composite / Efecto del tipo de fuente luz en la resistencia adhesiva de distintas resinas compuestas reparados con una resina bulk-fill

Abstract: The aim of this study was to evaluate and compare the effects of different light sources on shear bond strength when bulk-fill composite was used for the repair of different composite resins. A total of 126 samples made from six resin composites with different properties were aged (thermal-cycling with 5000 cycle), exposed to the same surface treatments and adhesive procedure. Then, they were repaired with a bulk-fill composite. At the polymerization step, each group was divided into three subgroups (n=7) and light cured with a QTH light source for 40s and two different LED light sources for 20s. Subsequently, the specimens were aged in distilled water at 37 ºC for 4 weeks and then subjected to shear bond strength test. Then, the specimens were examined under a stereomicroscope to identify modes of failure and visualized by Scanning Electron Microscope. Data obtained from the study were analyzed using ANOVA and Tukey HSD Test (α=0.05). In all groups, the light curing units had an impact on shear bond strength (p<0.05). Among the study groups, the greatest bond strength values were observed in the specimens repaired using the LED and the specimens repaired with the QTH light curing unit had the lowest bond strength values. It was concluded that the content of composite resins and light curing units may influence bond strength of different composites repaired with the bulk-fill composite.

Resumen: El objetivo de este estudio fue evaluar y comparar los efectos de diferentes fuentes de luz sobre la resistencia de la unión al cizallamiento cuando se utiliza una resina bulk-fill para la reparación de diferentes resinas compuestas. Se envejecieron un total de 126 muestras fabricadas con seis compuestos de resina con diferentes propiedades (ciclo térmico con 5000 ciclos), expuestas a los mismos tratamientos de superficie y procedimiento adhesivo. Luego, fueron reparadas con una resina bulk- fill. En el paso de polimerización, cada grupo fue dividido en tres subgrupos (n=7) y fotopolimerizado con una fuente de luz QTH por 40s y dos fuentes de luz LED por 20s. Posteriormente, los especímenes se envejecieron en agua destilada a 37 ºC durante 4 semanas y luego se sometieron a una prueba de resistencia adhesiva de cizalla. Luego, los especímenes fueron examinados bajo un estereomicroscopio para identificar los modos de falla y visualizados por el Microscopio Electrónico de Barrido. Los datos obtenidos del estudio fueron analizados usando el ANOVA y la prueba Tukey HSD (α=0.05). En todos los grupos, las unidades de fotopolimerización tuvieron un impacto en la fuerza de adhesión al cizallamiento (p<0,05). Entre los grupos de estudio, los mayores valores de fuerza de adhesión se observaron en los especímenes reparados utilizando el LED y los especímenes reparados con la unidad de fotopolimerización QTH tuvieron los valores de fuerza de adhesión más bajos. Se llegó a la conclusión de que el contenido de las resinas compuestas y las unidades de fotopolimerización pueden influir en la fuerza de adhesión de los diferentes compuestos reparados con resinas bulk-fill.

The Effects of Mouthwashes on the Color Stability of Resin-Based Restorative Materials / Efecto de los enjuagues orales en la estabilidad del color de materiales restauradores a base de resina

Abstract: Objective: This study investigated the effects of three types of mouthwash on the color stability of three resin-based restorative materials (nanohybrid resin composite, sonic-activated bulk-fill material, and compomer). Materials and Methods: To this end, 120 cylindrical disc specimens were prepared and polished, after which they were incubated in distilled water for 24 hours for post-polymerization. The baseline color values of each specimen were measured with a spectrophotometer, then the specimens were randomly divided into four groups. Following immersion in the mouthwashes for 24 hours, the specimens were rinsed with distilled water and dried before the color measurement was repeated. The values of color change (ΔE₀₀) were subsequently calculated. A two-way analysis of variance and Duncan's post hoc multiple comparison tests were conducted to determine statistically significant differences among the restorative materials. Results: All samples showed discoloration after immersion, albeit some instances of discoloration were imperceptible. In this respect, a statistically significant difference was found among the restorative materials and mouthwashes (p<0.05). Imperceptible ΔE₀₀ values were derived on the nanohybrid resin composite and compomer, but perceptible and acceptable ΔE₀₀ values were detected on the sonic-activated bulk-fill materials (p<0.05). The clinically unacceptable discoloration was observed on the sonic-activated bulk-fill composite immersed in Listerine®. Conclusions: Clinicians should make recommendations based on the potential staining capacity of mouthwashes prescribed for daily use in restorative materials. In this way, the need for renewal of restorations due to discoloration could be avoided.

Resumen: Objetivo: Este estudio investigó los efectos de tres tipos de enjuague bucal en la estabilidad del color de tres materiales de restauración a base de resina (resina nanohíbrida, resina bulk-fill de activación sónica y compómero). Materiales y Métodos: Para ello se prepararon y pulieron 120 muestras de discos cilíndricos, después de lo cual se incubaron en agua destilada durante 24 horas pospolimerización. Los valores de color de base de cada muestra se midieron con un espectrofotómetro, después las muestras se dividieron aleatoriamente en cuatro grupos. Tras la inmersión en los enjuagues bucales durante 24 horas, los especímenes se enjuagaron con agua destilada y se secaron antes de repetir la medición del color. Posteriormente se calcularon los valores de cambio de color (ΔE₀₀). Se llevó a cabo un análisis bidireccional de la varianza y las pruebas de comparación múltiple post hoc de Duncan para determinar las diferencias estadísticamente significativas entre los materiales de restauración. Resultados: Todas las muestras mostraron decoloración después de la inmersión, aunque algunos casos esta fue imperceptible. Se encontró una diferencia estadísticamente significativa entre los materiales de restauración y los enjuagues bucales (p<0,05). Se obtuvieron valores imperceptibles de ΔE₀₀ en el compuesto de resina nanohíbrida y el compómero, pero se detectaron valores perceptibles y aceptables de ΔE₀₀ en la resina bulk-fill activada sónicamente (p<0,05). Se observó una decoloración clínicamente inaceptable en la resina bulk-fill activada sónicamente inmersa en Listerine®. Conclusiones: Los clínicos deben hacer recomendaciones basadas en la capacidad potencial de coloración de los enjuagues bucales prescritos para uso diario en los materiales de restauración. De esta manera, se podría evitar la necesidad de renovar las restauraciones debido a la decoloración.