Clinical follow-up at 18 months of two bulk fill occlusal composite resins: a double-blind randomized clinical study / Seguimiento clínico a 18 meses de dos resinas compuestas oclusales bulk fill: estudio clínico aleatorio doble ciego

Objetive: To compare the clinical behavior of two types of Bulk Fill composite resins and a nanohybrid resin at 18 months in occlusal restorations. Material and Methods: Three occlusal restorations were performed in each one of the 55 participants. They were randomly distributed into three groups, TN: Tetric-N-Ceram Bulk-Fill, FK: Filtek Bulk-Fill, and Z350: Filtek Z350XT. Adhesive techniques and restorative procedures were performed according to the manufacturer's instructions for each restorative material used. In TN and FK an increment of 4mm was applied, and in Z350 increments of ≤2mm depth were applied. Two calibrated operators evaluated the restorations at baseline and at 18 months using the FDI World Dental Federations system (1: excellent, 2: good, 3: satisfactory, 4: unsatisfactory, 5: poor) for clinical marginal staining (MS) properties, fracture-retention (FR), superficial texture (ST), marginal integrity (MI), postoperative sensitivity (PS) and caries (C). Kruskal-Wallis and Wilcoxon were used to compare the 3 groups at 18 months (5% significance). Results: 38 patients with a total of 114 restorations were assessed, being evaluated with excellent clinical behavior; MI, 78.9% in Z350, 89.51% in TN and 81.6% in FK; ST 73.5% in Z350, 86.8% in TN, and 84.2% in FK; MS 84.2% in Z350, 84.2% in TN, and 91.2% in FK; PS 100% in Z350 and 97.3% in TN and FK; in C and FR, 100% in the 3 groups. There were no significant differences between the three groups (p>0.05). Conclusion: The three resins studied presented a good clinical performance at 18 months without showing significant differences in the clinical properties evaluated.

Objetivo: Comparar el comportamiento clínico a 18 meses en restauraciones oclusales entre dos tipos de resinas compuestas Bulk Fill y una resina nanohíbrida. Material y Métodos: En 55 participantes se realizaron 3 restauraciones oclusales en cada paciente, distribuidas aleatoriamente en 3 grupos, TN: Tetric-N-Ceram Bulk-Fill, FK: Filtek Bulk-Fill y Z350: Filtek Z350XT. Las técnicas adhesivas y procedimientos restauradores fueron realizados según las instrucciones de los fabricantes de cada material restaurador utilizado. En TN y FK se aplicó un incremento de 4mm y en Z350 se aplicó incrementos ≤ 2 mm de profundidad. Dos operadores calibrados evaluaron las restauraciones al baseline y a los 18 meses mediante el sistema FDI World Dental Federations (1: excelente, 2: aceptable, 3: suficiente, 4: insatisfactorio, 5: inaceptable) en las propiedades clínicas de tinción marginal (TM), fractura-retención (FR), textura superficial (TS), integridad marginal (IM), sensibilidad postoperatoria (SP) y caries (C). Se utilizó Kruskal-Wallis y Wilcoxon para la comparación de los 3 grupos a 18 meses (significancia de 5%). Resultados: Se controlaron 38 pacientes con un total de 114 restauraciones, siendo evaluados con comportamiento clínico excelente; IM, 78.9% en Z350, 89.51% en TN y 81.6% en FK; TS 73.5%, en Z350, 86.8% en TN y 84.2% en FK; TM, 84.2% en Z350, 84.2% en TN y 91.2% en FK; SP 100% en Z350 y 97,3% en TN y FK; en C y FR 100% en los 3 grupos. No hubo diferencias significativas entre los 3 grupos (p>0,05). Conclusión: Las 3 resinas estudiadas presentaron un buen desempeño clínico a 18 meses sin mostrar diferencias significativas en las propiedades clínicas evaluadas.

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.

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.

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.

Solving color irregularities with a bioactive bulk-fill restorative system: case report and 24-months follow up / Resolución de irregularidades de color con un sistema restaurador bulk-fill bioactivo: reporte de caso y seguimiento de 24 meses

Bulk-fill resin composites represent an excellent alternative to the conventional incremental layering technique for the reduction of polymerization stress on the adhesive interface. Marginal seal can be further improved by the incorporation of bioactive fillers, such as those encountered in Giomers. However, the high translucency required for the adequate polymerization of bulk-fill materials can seriously jeopardize the final aesthetic outcome of the restorations, especially in the presence of inhomogeneous or stained dentin substrates. The aim of this case report was to present the combined use of two bulk-fill Giomer materials (Beautifil Bulk Flowable and Beautifil II LS, Shofu) for the restoration of three posterior maxillary teeth displaying a black stained dentin substrate due to amalgam corrosion products. This technique allowed completion of the restorations with a satisfactory aesthetic and biomimetic outcome. The adequate preservation of the anatomy and function of the three restorations after 24-months follow-up, provides evidence of the enhanced marginal sealing capacity of these bioactive materials and the success of bulk-fill techniques over time.

Las resinas compuestas de tipo bulk-fill representan una excelente alternativa a la técnica incremental para la reducción de la tensión de polimerización sobre la interfaz adhesiva. La incorporación de rellenos bioactivos, como los que se encuentran en los materiales con tecnología giomer, refuerzan aún más el sellado marginal de estas restauraciones. Sin embargo, la alta translucidez, necesaria para la adecuada polimerización de los materiales tipo bulk-fill, puede comprometer seriamente el resultado estético final de las restauraciones, especialmente en presencia de sustratos dentarios no homogéneos u oscurecidos. El objetivo de este reporte de caso fue presentar el uso combinado de dos materiales giomer tipo bulk-fill (Beautifil Bulk Flowable y Beautifil II LS, Shofu) para la restauración de tres dientes maxilares posteriores con un sustrato dentinario ennegrecido debido a productos de corrosión de amalgama. Esta técnica permitió completar las restauraciones con un resultado estético y biomimético satisfactorio. La adecuada conservación de la anatomía y la función de las tres restauraciones tras un período de 24 meses, aporta evidencia sobre la adecuada capacidad de sellado marginal de estos materiales bioactivos y el éxito de las técnicas de restauración tipo bulk-fill en el tiempo.

Bulk-Fill Composite Restorations Step-by-Step Description of Clinical Restorative Techniques Case Reports / Restauraciones compuestas Bulk-Fill Descripción paso a paso de las técnicas de restauración clínica Informes de casos

ABSTRACT Composite resins are excellent materials for direct restorations in the posterior region, satisfactorily reestablishing esthetics and function. Recently, a new class of composites has been commercialized, the so-called Bulk-fill resins. These resins may be inserted in the dental cavity in increments of 4 to 5 mm thick, and have the advantages of reducing polymerization shrinkage and clinical working time. The aim of this case report was to describe the use of bulk-fill composite resins to restore Class I and Class II cavities by means of two different restorative techniques.

RESUMEN Las resinas compuestas son excelentes materiales para restauraciones directas en la región posterior, restableciendo satisfactoriamente la estética y la función. Recientemente, se ha comercializado una nueva clase de compuestos, las denominadas resinas Bulk Fill. Estas resinas pueden insertarse en la cavidad dental en incrementos de 4 a 5 mm de espesor, y tienen las ventajas de reducir la contracción de la polimerización y el tiempo de trabajo clínico. El objetivo de este informe de caso fue describir el uso de resinas Bulk fill para restaurar las cavidades de Clase I y Clase II mediante dos técnicas de restauración diferentes.

Nueva técnica de reconstrucción postendodóncica: resina bulk-fill intraconducto vs postes de fibra de vidrio / New postendodontic reconstruction technique: bulk-fill intracanal resin vs glass fiber posts

Introducción: El uso de postes de fibra de vidrio es el método actual más utilizado para la reconstrucción postendodóncica. Sin embargo, su adhesión sigue siendo impredecible debido al control limitado de su técnica de cementación. Las resinas bulk-fill revelan valores de fuerza flexural similares a la dentina y su empleo en la reconstrucción postendodóncica podría ser una alternativa viable y conservadora. Objetivo: Comparar tres técnicas de reconstrucción postendodóncica al medir su resistencia a fuerzas de desalojo, clasificar el tipo de fractura y falla adhesiva, evaluar su costo y tiempo de trabajo. Material y métodos: Se realizan 18 muestras divididas en tres grupos: grupo 1: poste más cemento de un paso, grupo 2: poste más cemento de tres pasos y grupo 3: reconstrucción postendodóncica con resina bulk-fill. Resultados: En la evaluación de la fuerza al desalojo no se encontró diferencia estadísticamente significativa en los tres grupos. Respecto al comportamiento y falla adhesiva, se encontró una diferencia significativa p < 0.001, favoreciendo a los grupos 2 y 3, por su adhesión en la porción radicular. El tipo de fractura fue restaurable para los tres grupos. Respecto al tiempo y costo, fueron significativamente menores para el grupo 3. Conclusión: En nuestro estudio no existió diferencia significativa en la fuerza al desalojo en los tres grupos; sin embargo, la hubo en el comportamiento, falla adhesiva, costo y tiempo, favoreciendo mayormente al grupo 3. La técnica de reconstrucción con resina puede ser una técnica predecible, suficientemente resistente, conservadora, rápida y de menor costo

Introduction: The use of fiberglass posts is the current method most used for post-endodontic reconstruction. However, its adhesion remains unpredictable due to the limited control of its cementing technique. Bulkfill resins reveal values of flexural strength similar to dentin and their use in post-endodontic reconstruction could be a viable and conservative alternative. Objective: Compare three post-endodontic reconstruction techniques by measuring their resistance to eviction forces, classifying the type of fracture and adhesive failure, evaluating their cost and time of work. Material and methods: 18 samples are divided into 3 groups: group 1: post plus cement of 1 step, group 2: post plus cement of 3 steps and group 3: post-endodontic reconstruction with bulk-fill resin. Results: In the evaluation of the force to the eviction, no statistically significant difference was found in the 3 groups. Regarding the behavior and adhesive failure, a significant difference was found p < 0.001, favoring groups 2 and 3, due to its adhesion in the root portion. The type of fracture was restorable for the 3 groups. Regarding time and cost, they were significantly lower for group 3. Conclusion: In our study there was no significant difference in the force to the eviction in the three groups, however there was in the behavior, adhesive failure, cost and time, favoring mainly the group 3. The technique of reconstruction with resin can be a predictable technique, Sufficiently resistant, conservative, fast and of lower cost (AU)

Effect of polishing methods on color change by water absorption in several composite resins

PURPOSE: The aim of this study was to evaluate the influence of polishing methods on the color stability of composite resins. MATERIALS AND METHODS: Two bulk-fill and four conventional resin composites were filled in cylindrical molds (6 mm diameter, 4 mm height) and light-cured. The specimens were stored in 34℃ distilled water for 24 h. Spectrophotometer was used to determine the color value according to the CIE L(*)a(*)b(*) color space. Each group was divided into three groups according to polishing methods (n = 5). Group 1 was control group (Mylar strip group), group 2 was polished with PoGo, and group 3 was polished with Sof-Lex Spiral wheels. Color evaluation was performed weekly for 4 weeks after immersion in 34℃ distilled water. The results were analyzed by generalized least squares method (P < 0.05). RESULTS: Generalized least squares analysis revealed that Sof-Lex Spiral wheels group showed the significantly lower ΔE values compared to PoGo and control group (P < 0.05). The ΔE values of polished group showed the significantly lower than the ΔE values of unpolished group (P < 0.05). Regarding color changes of composite resins, there was no significant difference between the ΔE values of Filtek Z250 and Filtek Z350 XT Universal restorative in all time intervals (P < 0.05). Tetric N-Ceram Bulk Fill showed the significantly lower ΔE values compared to other composite resins in 1, 2, 3 weeks (P < 0.05). CONCLUSION: Within the limitations of this study, polishing methods influence the color stabilities of composite resins. The group polished with Sof-Lex Spiral Wheels showed more resistance to discoloration than group polished with PoGo.

Color Stability of Bulk-Fill Resin Composites after Immersion in Different Media / 대한소아치과학회지

The aim of this study was to evaluate the color stability of bulk-fill and conventional resin composites with respect to different storage media and thickness of composites.Filtek™ Z250 and Filtek™ Z350XT were evaluated as conventional resin composites. Filtek™ Bulk-fill Posterior Restorative and Tetric® N-Ceram Bulk Fill were evaluated as bulk-fill resin composites.CIE L*a*b* values of baseline were measured after 24 hours of storage in distilled water, and each resin composite group was divided into three subgroups and stored in distilled water, red wine, and coffee media respectively. Again after 1, 7 and 28 days of immersion, color changes (ΔE*) were calculated using the CIE L*a*b* values.The greatest ΔE* was observed in red wine for all resin composites, and the mean color changes were ranked in the increasing order of distilled water, coffee, red wine. Filtek™ Z350XT exhibited the greatest color change in all media, followed by Filtek™ Bulk-fill Posterior Restorative. Filtek™ Z250 and Tetric® N-Ceram Bulk Fill followed with similar mean color change values. According to the 2 different thicknesses of 2 mm and 4 mm of bulk-fill resin composites, there was no thickness-related difference on color changes.

How do the optical properties of the bulk fill posterior composites change after 2 years of simulated toothbrushing? / Como as propriedades ópticas de compósitos bulk fill se comportam após 2 anos de escovação simulada?

Objective: The objective of this study was to evaluate the alteration of the optical properties of bulk fill resin-based composites after two years of simulated toothbrushing. Material and Methods: Three high-viscosity bulk fill resin composites and one conventional sculptable resin composite (control) were analyzed. Five specimens of each resin composite were prepared, and roughness, color, translucency and gloss were evaluated initially and after one and two years of simulated toothbrushing. The specimens were submitted to electric simulated toothbrushing (14600 strokes / 100 g) using a commercially available soft bristle toothbrush and toothpaste slurry in a proportion of 1:2 by weight. The brushing scheme was of 40 cycles per day (2 cycles per second / 280 cycles in a week). The optical properties and the roughness data were analyzed by a multifactor analysis of variance (MANOVA) and a Tukey post hoc test. Results: The baseline and final values of Ra and Sa were submitted to linear regression analyses, all of which were performed at a significance level of 5%. Gloss and roughness presented statistical differences between the resin-time interactions in all composite resins. The gloss (72.5%) and roughness (89.4%) worsened significantly after brushing, but the authors didn't find statistically significant differences when evaluating translucency and color. Conclusion: Based in the results, it could be concluded that the simulated brushing degraded the gloss and roughness of the used high-viscosity bulk fill composites. (AU)

Objetivo: O objetivo deste estudo foi avaliar a alteração das propriedades ópticas de resinas compostas do tipo bulk fill após dois anos de escovação simulada. Material e Métodos: Foram analisadas três resinas compostas do tipo bulk fill de alta viscosidade e uma resina composta convencional (controle). Cinco corpos-deprova de cada resina composta foram preparados e a rugosidade, cor, translucidez e brilho foram avaliados inicialmente e após um e dois anos de escovação simulada. Os espécimes foram submetidos a escovação dental simulada (14.600 golpes / 100 g) utilizando-se escova de dentes de cerdas macias comercialmente disponíveis e uma pasta composta de dentifrício e água na proporção de 1:2 em peso. O esquema de escovação foi de 40 ciclos por dia (2 ciclos por segundo / 280 ciclos por semana). As propriedades ópticas e os dados de rugosidade foram analisados por uma análise de variância multifatorial (MANOVA) e um teste post hoc de Tukey. Resultados: Os valores iniciais e finais de Ra e Sa foram submetidos a análises de regressão linear, todas realizadas ao nível de significância de 5%. O brilho e a rugosidade apresentaram diferenças estatísticas entre as interações resina-tempo em todas as resinas compostas. O brilho (72,5%) e a rugosidade (89,4%) pioraram significativamente após a escovação, mas os autores não encontraram diferenças estatisticamente significativas ao avaliar a translucidez e a cor. Conclusão: Com base nos resultados, pôde-se concluir que a escovação simulada degradou o brilho e a rugosidade das resinas compostas do tipo bulk fill avaliadas. (AU)

Clinical application and research progress of bulk-fill resin-based composites / 口腔疾病防治

@#Traditional resin-based composites have been placed in cavities by incremental layering technique. The shrinkage stress may result in microleakage, post-operative sensitivity which lead to the failed restorations. In 2009, bulk-fill resin-based composites were reported to have the capability to be placed and cured in 4-5 mm increments, because of the improved resin matrix, modified nano-hybrid fillers and new photo initiators. This group of materials can simplify operation in clinical application in addition to decrease shrinkage stress and polymerization shrinkage. The aim of this review is to summarize the classification and properties of bulk-fill resin-based composites and to discuss the development of these new materials in the future.

Color stability of bulk-fill and incremental-fill resin-based composites polished with aluminum-oxide impregnated disks

OBJECTIVES: This study aimed to evaluate the color stability of bulk-fill and nanohybrid resin-based composites polished with 3 different, multistep, aluminum-oxide impregnated finishing and polishing disks. MATERIALS AND METHODS: Disk-shaped specimens (8 mm in diameter and 4 mm in thickness) were light-cured between two glass slabs using one nanohybid bulk-fill (Tetric EvoCeram, Ivoclar Vivadent), one micro-hybrid bulk-fill (Quixfil, Dentsply), and two nanohybrid incremental-fill (Filtek Ultimate, 3M ESPE; Herculite XRV Ultra, Kerr) resin-based composites, and aged by thermocycling (between 5 - 55℃, 3,000 cycles). Then, they were divided into subgroups according to the polishing procedure as SwissFlex (Coltène/Whaledent), Optidisc (Kerr), and Praxis TDV (TDV Dental) (n = 12 per subgroup). One surface of each specimen was left unpolished. All specimens were immersed in coffee solution at 37℃. The color differences (ΔE) were measured after 1 and 7 days of storage using a colorimeter based on CIE Lab system. The data were analyzed by univariate ANOVA, Mann-Whitney U test, and Friedmann tests (α = 0.05). RESULTS: Univariate ANOVA detected significant interactions between polishing procedure and composite resin and polishing procedure and storage time (p 0.05). Polishing reduced the discoloration resistance of Tetric EvoCeram/SwissFlex, Tetric EvoCeram/Praxis TDV, Quixfil-SwissFlex, and all Herculite XRV Ultra groups after 7 days storage (p < 0.05). CONCLUSIONS: Discoloration resistance of bulk-fill resin-based composites can be significantly affected by the polishing procedures.

Color evaluation of low viscosity bulk-fill resin with composite resin capping layer

PURPOSE: The purpose of this study was to measure the color of low viscosity bulk-fill resin with a capping layer and to compare it with the color of microhybrid composite resin. MATERIALS AND METHODS: A low viscosity bulk-fill resin (SDR) and microhybrid composite resin of shade A2 (A2) or A3 (A3) were fabricated to 4 mm thickness and light cured for 20 seconds. CIE L*a*b* values of the resin specimens were measured with a colorimeter. Then shade A2 and A3 microhybrid composite resin was capped over low viscosity bulk-fill resins in 2 mm thickness (SA2, SA3). The resin specimens were light cured for 20 seconds and the color was measured and analyzed (n = 10). Color differences (DeltaE) between SA2 and A2, SA3 and A3 were also calculated. RESULTS: L* value was highest in SDR followed by SA2 and SA3. L* value of A2 and A3 was the lowest. a* value was lowest in SDR followed by SA2 and SA3, and A2 and A3 was the highest. b* value was lowest in SDR followed by A2 and SA2, and A3 and SA3 was the highest. DeltaE between A2 and SA2 (DeltaE = 3.4), and that between A3 and SA3 (DeltaE = 3.1) was lower than the perceptible color difference threshold of DeltaE = 3.7. CONCLUSION: DeltaE between low viscosity bulk-fill resin with a capping layer and microhybrid resin was lower than the perceptible color difference threshold.

Effect of resin thickness on the microhardness and optical properties of bulk-fill resin composites

OBJECTIVES: This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. METHODS: Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) L*a*b* system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to alpha = 0.05. RESULTS: The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. CONCLUSIONS: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.

Effect of resin thickness on the microhardness and optical properties of bulk-fill resin composites

OBJECTIVES: This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. METHODS: Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) L*a*b* system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to alpha = 0.05. RESULTS: The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. CONCLUSIONS: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.