Effect of low temperature and room temperature on the depth of cure of bulk-fill composite resins

The study analyzed the influence of temperature on the depth of cure of bulk-fill composite resins. Three discs (ISO 4049/2000) from each group were made, and four restorative materials were investigated: Opus Bulk-Fill Flow, Opus Bulk-Fill APS, Filtek™ One Bulk-Fill, and Filtek™ Bulk-Fill Flow. They were light-cured (Gnatus ± 1,200 mW/cm2) for 20 seconds, varying the temperature (23°C and 5°C) and simulating the use of the product both at room temperature and under refrigeration. The materials were inserted in aluminum matrices with 10 mm in depth and 4 mm in diameter. A clear film strip and a glass microscope slide were positioned at the top and bottom surfaces. The material was condensed and light-cured with the tip of the light source in close contact, for 20 seconds on the top surface. Immediately after irradiation, the samples were removed from the mold, and the uncured part was removed with a plastic spatula. The measurement was performed with a micrometer ± 0.1 mm, and the value was divided by 2. The data were analyzed with two-way ANOVA at a significance of 0.05. There was a statistical difference in the temperature between the results obtained in Opus Bulk-Fill APS (p <0.001) and Filtek™ Bulk-Fill Flow (p = 0.018) resins. For the temperature of 5°C, Filtek™ Bulk-Fill Flow showed a statistical difference compared to the other resins, while Opus Bulk-Fill Flow and Opus Bulk-Fill APS did not. For the temperature of 23°C, Filtek™ Bulk-Fill Flow maintained the statistical difference from the others, but Filtek™ One Bulk-Fill and Opus Bulk-Fill APS did not present statistical differences. Storing the Filtek™ Bulk-Fill Flow composite resin in the refrigerator caused a greater depth of cure than the other resins, and the depth of cure decreased at room temperature. As for Opus Bulk-Fill APS, the depth of cure decreased proportionally to the temperature decrease. The temperature may affect the depth of cure of some composite resins.

Pre-Heating effect on the microhardness and depth of cure of Bulk-Fill composite resins / Efecto del precalentamiento de las resinas compuestas Bulk-Fill en la microdureza y la profundidad de curado

Abstract The aim of this study was to investigate the effect of preheating three bulk-fill and one conventional composite resin on the Vickers microhardness and depth of cure of these composites. In this study, three bulk-fill composites- SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), and one conventional composite resin G-ænial POSTERIOR (GP) were used as the control group. The samples were obtained at room temperature (24°C) and at 55°C in T2 mode after being placed in a heating device for 10 minutes. The samples were divided into eight groups (n=10) according to the type of material and heating process that was utilized (preheated and nonheated). All samples were tested with a Vickers microhardness (VHN) tester on the bottom and top surfaces. The first measurements were obtained at baseline; the second set of measurements was performed after the samples were stored in distilled water at 37°C for 24 hours. The depth of cure was calculated using a bottom/top hardness ratio of measurements. Statistical analysis was performed utilizing the SPSS V23 and Shapiro-Wilk tests. Lastly, the Duncan test was used for multiple comparisons (p<0.05). While the VHN increased after the preheating procedure in bulk-fill composites, it decreased in GP. There was no difference between the baseline and the 24-hour VHN values in SDR and GP. After 24 hours, while the VHN of EST increased, the VHN of AFX decreased. There was no difference between the hardness ratios of the AFX and EST samples (p<0.001) and hardness ratios were greater than GP and SDR. When comparing the baseline and the 24- hour values, the VHN depended on the type of materials. Sufficient curing depth was obtained in all groups with a thickness of 2mm.

Resumen El objetivo fue investigar el efecto del precalentamiento de tres resinas Bulk-fill, una resina compuesta convencional sobre la microdureza Vickers y la profundidad de curado de estas resinas. Se utilizaron tres composites Bulk-Fill-SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), y una resina compuesta convencional G-ænial POSTERIOR (GP) como grupo de control. Las muestras se obtuvieron a temperatura ambiente (24°C) y a 55°C en modo T2 después de haber sido colocadas en un dispositivo de calentamiento durante 10 minutos. Se dividieron en ocho grupos (n=10) según el tipo de material y el proceso de calentamiento que se utilizó (precalentado y no calentado). Se probaron con un medidor de microdureza Vickers (VHN) en las superficies inferior y superior. Las primeras mediciones se obtuvieron en la línea de base; la segunda se realizó después de que las muestras se almacenaran en agua destilada a 37°C durante 24 horas. La profundidad de curado se calculó utilizando una relación de dureza inferior/ superior de las mediciones. El análisis estadístico se realizó utilizando el SPSS V23 y las pruebas de Shapiro-Wilk. Por último, se utilizó la prueba de Duncan para las comparaciones múltiples (p<0,05). VHN aumentó tras el procedimiento de precalentamiento en las resina Bulk-Fill, disminuyó en los GP. No hubo diferencias entre los valores de VHN de referencia y de 24 horas en SDR y GP. Después de 24 horas, mientras que el VHN de EST aumentó, el VHN de AFX disminuyó. No hubo diferencias entre los ratios de dureza de las muestras de AFX y EST (p<0,001) y los ratios de dureza fueron mayores que los de GP y SDR. Al comparar los valores de referencia y los de 24 horas, el VHN dependió del tipo de materiales. Se obtuvo una profundidad de curado suficiente en todos los grupos con un grosor de 2mm.

Effects of curing modes on depth of cure and microtensile bond strength of bulk fill composites to dentin

Abstract Objectives To compare the microtensile bond strength (µTBS) and depth of cure (DOC) of bulk-fill composites cured by monowave (MW) and polywave (PW) LED units using different curing times. Methodology Three composites were tested: Tetric EvoCeram Bulk Fill (TBF), Filtek Bulk Fill (FBF), and Tetric EvoCeram (T; control). Flat dentin surfaces treated with adhesive (AdheSE Universal®, Ivoclar Vivadent) were bonded with 4 mm cylindrical samples of each bulk-fill composite material (n=6) and cured with monowave (Satelec) or polywave (Bluephase Style) curing units for 10 or 20 seconds. After 24 hours, teeth were sectioned into individual 0.9 mm2 beams and tested for µTBS. Failure modes were analysed. Moreover, the DOC scrape test (IOS 4090) was completed (n=5) following the same curing protocols. Two-way ANOVA (a=0.05) was performed, isolating light-curing units. Results For samples cured with the MW light-curing unit, no significant effects were observed in the µTBS results between any of the resin composite brands and the curing times. Conversely, when resins were cured with a PW light unit, a significant effect was observed for TBF resin. In general, bulk-fill composites presented greater DOC and longer curing time resulted in higher DOC for all composites. Conclusion The µTBS of the composites to dentin was not affected by the curing mode of the resins, except for TBF cured with PW light unit. Bulk-fill composites exhibit greater DOC than conventional resin-based composites.

Ct Of Quartz-Tungsten-Halogen And Light-Emitting Diode-Curing Units On The Depth Of Cure And Flexural Strength Of A Nanohybrid Composite Resin: An In Vitro Study

Introduction: Over the years, the demand for esthetic dentistry has grown dramatically and there has been a rapid developmentof new adhesive restorative materials with nanotechnology that can restore the color and characteristics of natural tooth. Topolymerize these materials, light-curing dental materials extensively used are quartz-tungsten-halogen (QTH) and light-emittingdiode (LED)-curing units. Literature search revealed that depth of cure and flexural strength are the most important propertiesof composite resin materials, relevant to the clinical technique of incremental packing and curing.Purpose: The objectives of the present study were to evaluate and compare the depth of cure and flexural strength of ananohybrid composite resin.Materials and Methods: Two light-curing units were selected for this study: QTH (Bonart, Unicorn) and LED (Ivoclar Vivadent,Bluephase® N). The depth of cure was evaluated with scraping technique using digital caliper and flexural strength was evaluatedusing universal testing machine with a crosshead speed of 1 mm/min.Results: Descriptive statistics was employed to measure the mean and standard deviation of the depth of cure and flexuralstrength. Unpaired “t”-test was used to compare the study variables. Statistical significance was fixed at ≤0.05 and LED-curingunit showed significantly greater depth of cure and flexural strength when compared to QTH curing unit.Conclusion: Curing effectiveness of resin composite is dependent on the light-curing unit.

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.

Depth Of Cure And Mechanical Properties Of Bulk-Fill Posterior Dental Composites

The objectives of this study were to compare the microhardness, flexural strength and compressivestrength of a new bulk-fill composite (SonicFill™) to a conventional nanohybrid composite (HerculitePrecis) and an established bulk-fill composite (Tetric N Ceram). In addition, the depth of cure of thetwo bulk-fill resin composites was also investigated. The materials were prepared and tested for themechanical properties following ISO 4049:2009. Microhardness and depth of cure were measured usingVickers hardness tester. Compressive and flexural strength were tested using a universal testing machine.To determine the depth of cure, microhardness of the bulk-fill composites were measured as a functionof selected depth of materials at 0.5 mm, 2.0 mm and 4.0 mm. Data were analyzed by either one-wayANOVA or Friedman test. Analysis demonstrated that SonicFill™ gave the highest microhardness value(101.8 + 4.6 VHN) compared to the other two groups. There were no significant differences among allgroups in flexural and compressive strength. The depth of cure decreased as the thickness of both bulkfillcomposites increased. In conclusion, SonicFill™ showed favorable mechanical properties comparedto other composites tested. In both bulk-filled groups, microhardness value decreased as the thicknessof the composite increased. The polymerization of the bulk-filled composites was effective only at 2 mmor less.

Degree of conversion of resin composite cured by light through a translucent fiber posts

PURPOSE: This study evaluated the depth of cure of resin composite cured by light through a translucent fiber post. MATERIALS AND METHODS: The opaque plastic tubes in various lengths of 2, 4, 6, 8, 10, 12, 14 mm. were filled with resin composite in which two different translucent fiber posts were inserted into the center and photo-polymerized for 40 seconds. The degree of conversion of the cured composite at bottom surface were examined using Fourier transform infrared attenuated total reflection spectrometer (FTIR/ATR) at 0.1, 0.5 and 1.0 mm apart from the post surface. RESULTS: The degree of conversion of the 0.1 mm, 0.5 mm, 1.0 mm apart from the post surface was highest at the 2 mm level and continuously decreased when the distance from the light source was increased and drastically decreased when the depth from the top of the post was greater than 4-6 mm. For each level, the highest degree of conversion was at 0.1 mm from the post surface and decreased continuously when the distance apart from the post surface was increased. CONCLUSION: The quantity of light transmission depends on the type of post and the light transmission capability of the post, especially after 4-6 mm depth and the area further apart from the post surface, are insufficient for clinical light activation of resin composite.

Comparación de la profundidad de fotopolimerización de resinas fluidas a través de 4 porcelanas de alta opacidad / Comparison of the light cure depth of flowable resins through 4 high-opacity porcelains

Se estudia la profundidad de polimerización que se obtiene en resinas compuestas fluidas al ser iluminadas a través de bloques de cerámica de distinta composición y distintos grosores. En formadores metálicos cilíndricos de 4mm de alto y 6mm de diámetro se depositó resina fluida hasta enrasar en superficie y posteriormente se iluminó por 60 seg interponiendo las distintas cerámicas entre la luz y la resina. Se utilizó una lámpara led para la iluminación del material. Algunos de los grupos en estudio presentaron diferencias significativas entre sí dependiendo del grosor de la cerámica y el tipo de ella. Es posible polimerizar resina fluida a través de cerámicas de distinta opacidad obteniendo grosores de resina mayores a los que se establecen para la línea de cementación de las restauraciones de cerámica libre de metal. Relevancia: A través de bloques de cerámica de diferente opacidad y composición se obtiene polimerización de resina compuesta fluida, lo que permitiría usar esta resina como medio de cementación de restauraciones a base de cerámicas cuyos grosores permitan el paso de la luz.

We studied the depth of cure obtained in flowable composite resins when illuminated through ceramic blocks of different composition and different thicknesses. The flowable composite resin was deposited in forming metal cylinders of 4mm of high and 6mm of diameter, brought to volume and then illuminated for 60 sec interposing the different ceramics between light and resin. A LED lamp was used to illuminate the material. Some of the groups exhibited significant differences among them depending on the thickness of the ceramic and its type. Flowable resin may polymerize through ceramics of different thicknesses and could be used for the cementation of ceramic restorations.

Estudio comparativo de la microdureza de composites en relación a la fuente de luz, profundidad de polimerización y tiempo / Comparative study of microhardness of composites in relation to the light source, depth of cure and time

Evaluar la microdureza de las resinas Charisma (microhíbrida) y Z100 (híbrida) en relación a la profundidad de polimerización (8, 6, 4, 2 mm e 0 mm-superficial), la fuente de luz (Diodo emisión de luz-LED y Luz halógena de cuarzo-tungsteno-QTH) y los tiempos de análisis (inmediato, 24 h y 1 mes). Fueron testadas resinas Charisma (Kulzer) y Z100 (3M/ESPE). Para la realización del ensayo de microdureza fueron confeccionados 07 cuerpos de prueba de 8x2x4mm en matriz de carbono, con incrementos de 1mm cada y fotopolimerizados con los aparatos Optilux (Dabi Atlante) y LED (MMOptic). Los cuerpos de prueba fueron sometidos a los ensayos de dureza Vickers; inmediato, 24 horas y 1 mes después de la confección, almacenados en agua destilada y estufa a 37 1ºC. El análisis de microdureza fue realizada por medio del microdurómetro Shimadzu HMV-2000, con 5s de indentación y 500g de peso. La dureza fue evaluada en diferentes profundidades (superficie externa, 2, 4, 6 y 8 mm). Los resultados fueron estadísticamente significantes (p=5%) para todas las condiciones experimentales. Ambas resinas tuvieron la microdureza disminuida conforme el aumento de la profundidad y presentaron valores mayores con el aparato de luz halógena que con el aparato de diodo. La resina Z100 presento mayores valores de microdureza en relación a la resina Charisma. De acuerdo con los resultados, se puede concluir que cuanto mayor la profundidad menor la dureza y el aparato QTH proporcionó mayor grado de polimerización

To evaluate the microhardness of the resins Charisma (microhybrid) and Z100 (hybrid) in respect to the depth of polymerization (8, 6, 4, 2 mm and 0 mm-superficial), the source of light (Emitting Diode of light-LED and halogenous quartz-tungsten-QTH Light) and the analysis times (immediate, 24 h and 1 month). Resins Charisma (Kulzer) and Z100 were tested (3M/ESPE). For the accomplishment of the microhardness essay 07 were confectioned body-of-test of 8x2x4mm in carbon matrix, with increments of 1mm each and photopolymerised with Optilux devices (Dabi Atlante) and LED (MMOptic). The body-of-test was submitted to the essays of Vickers hardness; immediate, 24 hours and 1 month after the confection, stored in distiled water and heat 37±1ºC. The microhardness analysis was accomplished by means of the microdurometer Shimadzu HMV-2000, with 5s and 500g of load. The hardness was evaluated in different depths (external surface, 2, 4, 6 and 8 mm). The results were statistically significant (p=5%) for all the experimental conditions. Both resins had had the microhardness diminished as the increase of the depth and had presented bigger values with the device of halogenous light that with the diode device. The Z100 resin presented greaters values of microhardness in respect to the Charisma resin. In accordance with the results, it can be concluded that how much bigger the depth lesser the hardness and device QTH provided to greater polymerization degree

The polymerization rate and the degree of conversion of composite resins by different light sources / 대한치과보존학회지

OBJECTIVES: The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue Light Emitting Diode Light Curing Units (LED LCUs) compared with conventional halogen LCUs. MATERIALS AND METHODS: First, thermal analysis was performed by a differential scanning calorimeter (DSC). The LED LCU (Elipar Freelight, 320 mW/cm2) and the conventional halogen LCU (XL3000, 400 mW/cm2) were used in this study for curing three composite resins (SureFil, Z-250 and AEliteFLO). Second, the degree of conversion was obtained in the composite resins cured according to the above curing mode with a FTIR. Third, the measurements of depth of cure were carried out in accordance with ISO 4049 standards. Statistical analysis was performed by two-way ANOVA test at 95% levels of confidence and Duncan's procedure for multiple comparisons. RESULTS: The heat of cure was not statistically different among the LCUs (p > 0.05). The composites cured by the LED (Exp) LCUs were statistically more slowly polymerized than by the halogen LCU and the LED (Std) LCU (p < 0.05). The composite resin groups cured by the LED (Exp) LCUs had significantly greater degree of conversion value than by the halogen LCU and the LED (Std) LCU (p = 0.0002). The composite resin groups cured by the LED (Std) LCUs showed significantly greater depth of cure value than by the halogen LCU and the LED (Exp) LCU (p < 0.05).

Effect of hema and tegdma on the properties of experimental composite resins / 대한치과보철학회지

PURPOSE: The purpose of this study was to compare HEMA and TEGDMA as diluents for the composite resin. MATERIAL AND METHODS: Eight kinds of experimental light curable composite resins were prepared and used. Concentrations of monomer and filler were same for all experimental composites, except, the diluent's ratios to the monomer. The ratio of diluents to Bis-GMA were 15%, 20%, 25%, and 30%, and two kinds of diluents were used, so total experimental groups were eight including one control group of 25% TEGDMA. RESULTS: Depth of cure, flexural strength, shear bond strength to bovine enamel, shear bond strength to bovine dentin, water absorption and solubility of composites in water were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values, and regression test for two diluents and four concentrations, Duncan's multiple range test, and Two-way ANOVA test were done for kinds of diluents and its concentrations at level of 0.05. CONCLUSION: Following results were obtained; 1. There were not significant differences in effects of HEMA and TEGDMA to depth of cure, flexural strength of composites and shear bond strength to bovine enamel (p>0.05). 2. Increase of the concentrations of the diluents made the depth of cure (p<0.001) and flexural strength (p<0.05) a little higher. 3. Shear bond strength to dentin was higher on HEMA containing composites than TEGDMA containing composites (p<0.001). 4. Water absorption was higher on HEMA containing composites than TEGDMA containing composites (p<0.01).