Bulk-fill Resin Composites Research Articles

Color Stability of Bulk-Fill Flowable Resin Composites After Artificial Aging

Background: This study aimed to evaluate the color stability of bulk-fill flowable resin composites with 2 difference shades at baseline and after artificial aging. Methods: Disk-shaped specimens (Ø10 × 4 mm) were fabricated from three bulk-fill flowable resin resin composites (Filtek Bulk-Fill Flow, Venus Bulk-Fill Flow, and Estelite Bulk-Fill Flow). The specimens in each bulk-fill resin composite group were divided into two subgroups (n = 10 per subgroup) with two different shades, A1 (N = 30) and A3 (N = 30), and were polymerized with light curing (800 mW/cm2/Valo LED Unit, Ultradent) and polished. The color difference between bulk-fill resin composites was evaluated at baseline and after artificial aging using a spectrophotometer (CM-700d, Konica Minolta, Tokyo, Japan) under D65 illumination. Color coordinates were measured with CIEDE2000, and color differences (∆E00) and relative translucency parameter (RTP) values were calculated. Subsequently, the comparison of color changes (∆E00) before and after thermocycling was performed using the t-test for paired samples. Results: The bulk-fill flow resin composites evaluated in the present study were capable of mimicking important optical properties such as light transmission. All the resin composites provided acceptable color stability at baseline and after thermocycling when the color A1 was used. On the other hand, whenever the shade A3 was used, the Venus Bulk-Fill Flow demonstrated the best optical properties. There was no statistically significant difference when comparing baseline and after thermocycling in bulk-fill flowable resin composites (p > 0.05). After thermocycling, A1 bulk-fill flowable resin composites provided acceptable color stability, and all A3 bulk-fill flowable resin composites provided visible color change, except for the Venus Bulk-Fill Flow (∆E00 = 2.35). Conclusions: Estelite Bulk-Fill Flow displayed the best color stability (∆E00 = 2.22) between all the combinations evaluated.

Clinical Outcomes of Bulk-Fill Resin Composite Restorations: A 10-Year Mapping Review and Evidence Gap Map.

To map the evidence regarding the clinical performance of posterior restorations with bulk-fill resin composites and identify research gaps. This mapping review was conducted following PRISMA-ScR guidelines for scoping reviews, and its protocol was registered on the Open Science Framework platform. Systematic searches were conducted, considering studies published between 2013 and February 2024 in the PubMed, Embase, and Cochrane databases. Clinical studies investigating the performance of bulk-fill resin composite restorations in class I and/or class II preparations with increments of 4 to 5 mm were included. A total of 147 articles were identified, and based on the eligibility criteria, 26 studies were selected for descriptive analysis. Of the reviewed studies, 73% (n = 19) investigated high-viscosity bulk-fill composites, while 30% (n = 8) focused on low-viscosity bulk-fill composites. Evaluation periods ranged from 1 week to 10 years. Reported annual failure rates varied from 0% to 3%, with survival rates between 78.9% and 100%. Bulk-fill resin composites of high viscosity were the most analyzed in the published studies, with evaluation periods of up to 10 years. The review of available scientific evidence showed clinically acceptable performance for composite bulk-fill restorations, with high survival rates and minimal annual failure rates. There is a need for long-term clinical studies on bulk-fill resin composites. This review demonstrates that both high and low-viscosity bulk-fill resin composites exhibit satisfactory clinical performance, which can help clinicians optimize chairside time. However, it is important to highlight the need for further studies with longer follow-up periods.

24 Months clinical prospective of proximal restorations with repeated preheating bulk fill composite up to ten cycles: randomized controlled trial

This study aimed to clinically evaluate the performance of non-preheated bulk fill resin composite in class II cavities versus one, five and ten-time preheating cycles at 68 °C. Eighty-four recruited participants were randomly allocated into four groups (21 patients per group). One posterior Bulk-fill proximal restoration was performed for each participant according to the preheating cycles where in group I; teeth were restored with non-heated resin composite, group II: One preheating cycle of composite syringe was performed prior restoration, and group III: five preheating cycles while for group IV: Ten preheating cycles were performed. These restorations were clinically evaluated at 6, 12, 18 and 24 months. Statistical analysis was performed using one way ANOVA, with set p-value < 0.05. The results revealed that there was perfect agreement between both observers and observations WK (95% CI) [0.908 (0.780:1.000)] and [0.940 (0.824:1.000)], respectively. All restorations showed acceptable clinical performance with alpha and bravo scores. No replacement was required for any restoration. No statistically significant differences were detected between the control and intervention groups across all parameters during the various evaluation stages. It could be concluded that the clinical performance of ten cycles of repeated preheated bulk fill resin composite was equivalent to that of non-preheating resin composites after 24 months follow-up period, with great improvement in manipulation. Preheating of resin composite could be performed up to ten cycles prior to placement without any clinical adverse consequences on the performance of the restoration.

Immediate and Delayed Repair Of Bulk-Fill Composite Resin

Immediate and Delayed Repair Of Bulk-Fill Composite Resin

The Impact of Modeling Liquids on Surface Roughness and Color Properties of Bulkfill Resin Composites After Simulated Tooth Brushing: An in Vitro Study. Part I.

To evaluate the effect of different modeling agents on color changes, surface roughness, and translucency parameters over time in Bulkfill resin composites. Sixty specimens were prepared using three Bulkfill resin composites (Tetric N-Ceram Bulkfill, Filtek One Bulkfill and Opus Bulkfill) and three modeling agents (Wetting Resin, Optibond FL and Ambar APS). All specimens were subjected to a simulated tooth-brushing (Baseline, 50.000 cycles, 100.000 cycles), and surface roughness was measured at each interval. Surface topography was evaluated. The translucency parameter and color changes were assessed after 24-h, 7-, 14- and 30-day immersion in water, wine, and coffee. Data was analyzed using ANOVA and Bonferroni test. All specimens increased roughness after simulated tooth-brushing (p < 0.05). Wetting Resin decreased roughness on Tetric N-Ceram Bulkfill (p < 0.05). The translucency parameter remained unaltered for all groups. All groups changed color after 30-days of immersion in wine and coffee (p < 0.05). Ambar APS and Wetting Resin on Tetric N-Ceram Bulkfill showed higher color changes when immersed in coffee (p < 0.05). The use of modeling agents does not jeopardize translucency properties but may affect surface roughness and color properties of Bulkfill resin composites depending on their composition. The findings of this study suggest that surface roughness and color properties are affected by the differences in the composition between modeling agents and Bulkfill resins composites.

In Vitro Fracture Strength of Primary Canine Teeth Reinforced With Prefabricated and Customized Fiber-Reinforced Post Systems.

The demand for esthetics has increased in today's worldand most parents prefer to preserve their children's primary anterior teeth until their natural exfoliation. However, an intracanal post is required to provide retention for reconstruction of severely damaged anterior teeth due to caries or trauma. Various materials and methods may be used for the fabrication of intracanal posts. This study assessed the fracture strength and fracture mode of primary canine teeth reconstructed with prefabricated and customized polyethylene and glass fiber posts. This in vitro study evaluated 60 extracted primary canine teeth in four groups (n = 15). After pulpectomy and post space preparation with 4 mm depth, composite resin post, prefabricated glass fiber post (Whitepost), customized glass fiber post (Interlig), or customized polyethylene fiber post (Ribbond) were placed in the root canals to provide retention, and the tooth crown was restored with bulk-fill composite resin. The fracture strength was then measured in a universal testing machine. The fracture mode was also evaluated visually. The mean fracture strength was 22.45 ± 5.06, 33.10 ± 8.5, 30.20 ± 7.33, and 32.61 ± 5.73 N/mm2 in the composite resin post, Whitepost, Interlig, and Ribbond groups, respectively. The fracture strength was significantly lower in the composite group than in the remaining three groups (p = 0.000). No other significant differences were found (p > 0.05).Also, no significant difference was observed among the study groups in the fracture mode (p = 0.241). The composite resin post yielded a significantly lower fracture strength than the prefabricated and customized glass and polyethylene fiber posts, but the fracture mode was not significantly different among the four groups.

Effect of carbamide peroxide treatment on the ion release of different dental restorative materials

BackgroundTo predict the long-term performance of restorative materials in the oral environment, it is important to evaluate their resistance to chemical and mechanical degradation and to know the toxic potential of the type and amount of ions eluted from the filling material. In this study, home bleaching was applied to dental materials with different contents and it was aimed to determine the type and amount of ions released from these materials.MethodsIn this study, amalgam, posterior composite resin, anterior composite resin, bulk fill composite resin, indirect composite resin, hybrid ceramic and all-ceramic were used as restorative materials. 10 specimens of each material were prepared according to the manufacturer’s instructions. Each material group was divided into two subgroups as the bleached group and the control group. After bleaching, all specimens were stored in 1 ml of 75% ethanol/water solution. Solutions were renewed after 1, 14 and 28 days. The type and amount of ions released from the materials were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Data were analyzed using the Friedman, Wilcoxon Signed Ranks, and Mann-Whitney U tests (α = 0.05).ResultsIt was determined that the amount of ions release from the restorative materials decreased over time (p < 0.05). According to the results of the Mann-Whitney U test, there was no difference between the bleaching and control groups in most of the restorative materials (p > 0.05).ConclusionWithin the limits of this study, home bleaching system does not have a significant effect on ion release from restorative materials.

BASE SURFACE TEMPERATURE OF BULK FILL RESIN COMPOSITE WITH DIFFERENT THICKNESS

Background: The material thickness is one factor that influences the polymerization of resin composites. Bulk fill resin composite is an efficient dental resin composite restoration material because it can be cured to a thickness of up to 4-5 mm. The thickness of the material can also affect the temperature rise, while maintaining the temperature is very important because a significant increase can damage the pulp. Purpose: This research aimed to analyze the base surface temperature of bulk fill resin composite with different thicknesses. Methods: Thirty bulk fill resin composite samples with a diameter of 5 mm were divided into three groups with different thicknesses, namely group I (3 mm), group II (4 mm), and group III (5 mm). Each group of samples was cured using an LED Light Curing Unit for 20 seconds, and carried out simultaneously with the measurement of the base surface temperature using a type-K digital thermocouple. Data analyzed using One Way ANOVA and LSD post hoc tests. Results: The mean and standard deviation of the base surface temperature of bulk fill resin composite in groups I, II, and III, respectively, is 37.56 ± 1.06oC, group II 36.89 ± 1.23oC, and group III 36.00 ± 1.2 oC. It showed significantly different between the groups (p&lt;0,05). Conclusion: The thicker the bulk fill resin composite, the lower the base surface temperature.

Mechanical properties of dual-polymerizing resin-core material, dual-polymerizing resin cement, and bulk-fill composite resin used for restoring endodontically treated teeth

How resin-based material and a light-activation protocol influence the mechanical properties of materials used to cement glass fiber post-and-cores in endodontically treated teeth is unclear. The purpose of this in vitro study was to evaluate the influence of immediate or 5-minute delayed light activation on the mechanical properties of dual-polymerizing resin cements and dual-polymerizing resin-core materials compared with bulk-fill composite resins. Nine resin-based materials were tested: 4 dual-polymerizing resin-core materials, (Allcem Core; FGM, LuxaCore Z; DMG, Rebilda DC; VOCO, and (Clearfil DC Core Plus; KURARAY), 3 dual-polymerizing resin cements, (RelyX Universal; 3M ESPE, RelyX U200; 3M ESPE, and Allcem Dual; FGM), and 2 bulk-fill composite resins, (Opus Bulk Fill APS; FGM, and Filtek One Bulk Fill; 3M ESPE). The dual-polymerizing materials were light activated using both protocols. The postgel shrinkage (Shr), flexural strength (FS), elastic modulus (E), Knoop hardness (KH), degree of conversion (DC), and depth of polymerization (DoP) were measured (n=10). The data for Shr, FS, E, and DoP were analyzed using 2-way ANOVA, and for KH and DC using 2-way repeated measurement ANOVA and the Tukey HSD test (α=.05). A 5-minute delay before light-activation significantly reduced Shr for all materials (P<.001). Increasing the depth significantly reduced the KH for all materials (P<.001). Bulk-fill composite resins and dual-polymerizing resin-core had higher KH values than dual-polymerizing resin cements (P<.001). Delayed 5-minute light-activation reduced postgel shrinkage and had no negative effect on mechanical properties. Dual-polymerizing resin-core materials exhibited higher KH values than dual-polymerizing resin cement and mechanical properties similar to those of bulk-fill composite resin.

Repair bond strength of aged non methacrylate ORMOCER based bulk fill resin composite. An in-vitro study.

Repair bond strength of aged non methacrylate ORMOCER based bulk fill resin composite. An in-vitro study.

Marginal integrity and physicomechanical properties of a thermoviscous and regular bulk-fill resin composites.

To evaluate the marginal integrity (MI%) and to characterize specific properties of a thermoviscous bulk-fill resin composite, two regular bulk-fill resin composites, and a non-bulk-fill resin composite. VisCalor bulk (VBF), Filtek One Bulk Fill (OBF), and Aura Bulk Fill (ABF) were evaluated. Filtek Z250 XT (ZXT) was used as non-bulk-fill control. MI% was evaluated in standardized cylindrical cavities restored with the composites by using a 3D laser confocal microscope. The following properties were characterized: volumetric polymerization shrinkage (VS%), polymerization shrinkage stress (Pss), degree of conversion (DC%), microhardness (KHN), flexural strength (FS), and elastic modulus (EM). Data were analyzed by one-way and two-way ANOVA, and Tukey HSD post-hoc test (α = 0.05). VBF presented the highest MI% and the lowest VS% and Pss (p < 0.05). DC% ranged from 59.4% (OBF) to 71.0% (ZXT). ZXT and VBF presented similar and highest KHN than OBF and ABF (p < 0.05). ABF presented the lowest FS (p < 0.05). EM ranged from 5.5 GPa to 7.7 GPa, with the values of ZXT and VBF being similar and statistically higher than those of OBF and ABF (p < 0.05). Thermoviscous technology employed by VisCalor bulk was able to improve its mechanical behavior comparatively to regular bulk-fill resin composites and to contribute to a better marginal integrity in restorations built up in cylindrical cavities with similar geometry to a class I cavity as well. Although presenting overall better physicomechanical properties, Z250 XT presented the worst MI%. The marginal integrity, which is pivotal for the success of resin composite restorations, could be improved using VisCalor bulk-fill. The worst MI% presented by Z250 XT reinforces that non-bulk-fill resin composites shall not be bulk-inserted in the cavity to be restored.

Evaluation of the shear bond strength between CAD/CAM blocks and sonic/thermoviscous bulk-fill composites with different surface treatments

Background/purposeTo evaluate the shear bond strength (SBS) of nanoceramic hybrid CAD/CAM blocks with two bulk-fill composites in deep margin elevation following different surface pretreatments. Materials and methodsForty cylindrical-shaped samples (3 mm diameter × 4 mm height) were prepared from each group of bulk-fill resin composites (BRC) (SonicFill 3/SF, VisCalor bulk/VS), and 80 samples (14.5 mm × 7.2 mm × 2 mm) were sectioned from Grandio Block. Specimens of each BRC were assigned to two subgroups, and surfaces of one group were treated with a tribochemical silica-coating. The CAD/CAM block sample surfaces were treated with Al2O3 particles. CAD/CAM block and composite samples were luted using dual-cure universal resin-based cement (Bifix QM). Following immersion in distilled water for 24 h, the samples were divided as immediate and test groups. The test group was subjected to thermocycle (5–55 °C, 10,000 cycles). The SBS of the resin-based cement between the blocks and BRC was tested on a universal testing device until failure. Failure type was determined using a stereomicroscope. The roughening pattern was evaluated with SEM. Statistical analysis included Shapiro Wilk, Generalized Linear Models, and Fisher's Exact tests (P < 0.05). ResultsNo statistically significant difference was found between the mean SBS values according to deep margin elevation materials and surface pretreatment (P > 0.05). Aging procedure resulted in a statistically significant difference between the mean SBS values (P < 0.001). While the mean SBS value was 33.7 ± 7.9 MPa in immediate group, it was calculated as 22.6 ± 6.3 MPa in test group following thermocycle. ConclusionIn terms of SBS, both bulk-fill resin composites performed similarly. Although higher SBS values were obtained with tribochemical silica-coating, the adverse effects of thermocycling on bonding could not be prevented.

Comparison of degree of conversion performance of bulk-fill resin composites: A systematic review and network meta-analysis of in vitro studies

ObjectivesTo systematically compile data on the degree of conversion (DC) for bulk-fill composites using a network meta-analysis. MethodsA systematic search for in vitro studies of DC of bulk-fill composites was performed in PubMed, Web of Science, Scopus, and Open Grey. Risk of bias within studies and due to missing evidence was assessed using the Joanna Briggs Institute scoring system and ROB-MEN tool, respectively. The primary outcome was the DC of bulk-fill composites. Surface Under the Cumulative Ranking curve (SUCRA) was used to rank relative performance. Inconsistencies in the model were investigated to ensure its validity and the level of confidence in the network meta-analysis (CINeMA) was assessed. ResultsA total of 28 studies were included in the quantitative analysis. The average DC values (%) for 0-h/top, 0-h/bottom, 24-h/top, and 24-h/bottom were 59.09, 57.14, 66.73, and 63.87, respectively. According to their SUCRA ranking, the best-performing composites were: SonicFill, Venus Bulk Fill, and SDR (0-h/top), Reveal HD, i-Flow Bulk Fill, and Venus Bulk- Fill (0-h/bottom), Venus Bulk Fill, SDR, and QuiXfil (24-h/top), and Venus Bulk Fill, Aura Bulk Fill, and i-Flow Bulk Fill (24-h/bottom). Incoherence between direct and indirect evidence was identified as the most significant factor affecting confidence. ConclusionsDC values of bulk-fill composites were within the range commonly reported for previous generations of “conventional” composites, with flowable composites tending to perform better than sculptable composites. High variability in DC data was observed, which may be attributed to incompletely understood methodological differences. Clinical significanceDC is a fundamental parameter that influences multiple mechanical and biological properties of resin composites and is particularly relevant for the group of bulk-fill composites that are designed for use in thick layers.

Influence of Different Application Modes of a Universal Adhesive System on the Bond Strength of Bulk-Fill Composite Resin to Enamel and Dentin in Primary Teeth.

The objective of this study was to assess how the application mode of a universal adhesive system affects the microshear bond strength (μSBS) of bulk-fill and conventional composite resins to enamel and dentin in primary teeth. A total of 80 caries-free primary second molars were randomly assigned to eight experimental groups (n = 10) based on the bonding substrate (enamel or dentin), the application mode of the universal adhesive system (etch and rinse [E&R], or self-etch [SE]), and the type of composite resin used (bulk-fill or conventional). After bonding the composite resin to enamel or dentin, the μSBS of the bonded composite resins was measured. The mean μSBS value of bulk-fill composite resin was significantly higher than that of conventional composite resin for both enamel and dentin substrates, regardless of the application mode (p < 0.001). An interaction effect between the bonding substrate and the application mode of the adhesive system was observed, indicating a significant relationship (p < 0.001). The highest μSBS values for primary teeth enamel were achieved using the E&R mode with bulk-fill composite resin, while for dentin specimens, the SE mode with bulk-fill composite resin yielded the highest μSBS values. The μSBS of the E&R group was significantly higher than that of the SE group for enamel specimens (p < 0.001), whereas the μSBS of the SE group was significantly higher than that of the E&R group for dentin specimens (p < 0.001). Bulk-fill composite resin demonstrated higher μSBS in comparison to conventional composite resin. The universal adhesive system exhibited superior performance in the SE mode compared to the E&R mode on primary dentin. Pre-etching the enamel before the application of the universal adhesive enhanced the μSBS to primary teeth enamel, highlighting the importance of selectively acid etching the enamel of primary teeth.

Comparison of a self-adhesive resin cement, a conventional and a bulk-fill resin composite for luting of indirect restorative materials; the effect of thickness and material factors on translucence, monomer conversion and resin-dentin bond strength

Introduction: With developing technology, the search for the most ideal material to be used in the cementation of indirect restorations continues. To determine the effect of thickness and material factors on monomer conversion, translucency, and resin-dentin bond strength in luting indirect restorative materials (IRM) of different thicknesses using a resin cement, a conventional and a bulk-fill resin composite. Materials and methods: Samples of lithium disilicate glass-ceramic material (IPS e.max) and ceramic-resin hybrid material (Lava Ultimate) in 2 and 4 mm thicknesses, were luted using RelyX U200 (a self-adhesive resin cement), X-tra fil (a bulk-fill resin composite) and Z250 (a conventional microhybride resin composite) to the dentin surface and subjected to bond strength test after thermal cycle. In addition, the translucency parameter (TP) of the prepared blocks and the degree of conversion (DC) of the luting materials were investigated. The data was statistically analyzed. Results: The bond strength of X-tra fil and Z250 was statistically higher than RelyX U200 (p0.05). The increase in thickness decreased the TP of IRMs and the DC of resins underlying Lava (p0.05). Conclusion: Conventional and bulk-fill resin composites can be alternative luting materials to resin cements. Thickness increase did not change bond strength, while decreased TP, and DC only for Lava Ultimate.

ERRATUM (An erratum has been prepared for the following articles in the 33rd volume and 2nd issue of Current Research in Dental Sciences in 2023.)

Erratum An erratum has been prepared for the following articles in the 33rd volume and 2nd issue of Current Research in Dental Sciences in 2023. - In the article titled "Özyurt E, Kurt A. Effect of Different Teas on Surface Roughness of Conventional and Bulk-Fill Composite Resins Beverage Effect on Composite Resins. Curr Res Dent Sci. 2023; 33(2): 84-89", a patient consent draft was added inadvertently, even though there was no participant. - In the article titled "Keleş ZH, Ozan G. Effect of preheating on the microhard- ness and depth of cure of two composite resins with and without BIS-GMA. Curr Res Dent Sci. 2023; 33(2): 79-83", a patient consent draft was added inadvertently, even though there was no participant. - In the article titled “Yamalı AY, Turhan Bal B. Properties and clinical applications of lithium disilicate ceramics. Curr Res Dent Sci. 2023; 33(2): 122-130” although the article titled is a compilation, a patient consent draft was mistakenly included. - In the article titled "Eriş Derkuş F, Yılmaz UN. Demographic Analysis, Diagnosis, and Treatment Methods of Maxillofacial Trauma Cases in the Southeastern Anatolia Region of Turkey: Retrospective and Comparative Analysis. Curr Res Dent Sci. 2023; 33(2): 103-107", it was forgotten to write Dicle University in the sections left as XXX in the Methods section for the sake of article blindness. - Since the study titled “Yıldızer Keriş E. Comparison of Articular Eminence Steepness in Patients With Temporomandibular Joint Disc Disorders. Curr Res Dent Sci. 2023; 33(2): 117-121” was retrospective, patient consent could not be obtained and this information was forgotten to be added. - In the article titled “Şener E, Baksı Şen G. 3D Modelling and virtual planning technologies in dentistry. Curr Res Dent Sci. 2023; 33(2): 131-134” although the article titled is a compilation, a patient consent draft was mistakenly included.

Push-Out Bond Strength of Fiber Posts to Overflared Root Canals in Different Root Regions: Effect of Reinforcement Techniques.

Objectives: This study aimed to investigate the effect of different reinforcement techniques on the push-out bond strength of fiber posts to over-flared root canals. Materials and Methods: Forty-eight extracted human single-canal premolars were endodontically treated, over-flared, and randomly divided into four groups (N=12) including SARC: luting with self-adhesive resin cement, DCC: luting with dual-cure core build-up resin composite, CRR: relining root canal walls with bulk-fill resin composite, and DAP: relining fiber post with bulk-fill resin composite. After 24 hours, the roots were sectioned to obtain three cervical, middle, and apical 3mm slices. The push-out test was performed and failure pattern was examined. Kruskal-Wallis and post-hoc Dunn-Bonferroni tests were used for statistical analysis (P<0.05). Results: In all three regions, the lowest and highest bond strength was found in the SARC and DAP groups, respectively. In the middle region, there was a statistically significant difference between the bond strength of the SARC group and that of the DCC (P=0.044), CRR (P=0.021), and DAP (P<0.001) groups. There was no significant difference in the apical region. The lowest bond strength was observed in the apical region, and the highest was related to the cervical region. Adhesive failure was the most common failure pattern in all groups. Conclusion: Based on our results DCC, CRR and DAP methods increased bond strength in the middle and cervical sections of over-flared root regions. Considering that DCC is the easiest and most practical method, we propose that CRR and DAP can be replaced with this method in clinical procedures.

Effect of Polishing Systems on the Surface Roughness and Color Stability of Aged and Stained Bulk-Fill Resin Composites.

The aim of this study is to investigate how two different polishing techniques affect the color stability, surface roughness, and changes in surface morphology of aged and coffee-stained bulk-fill resin composites. A total of 112 disc-shaped samples were prepared using Omnichroma Flow Bulk (OB), Charisma Bulk Flow One (CB), Estelite Bulk Fill Flow (EB), and Estelite Sigma Quick (control). Samples were divided into two subgroups (n = 16) and aged using thermocycling. A profilometer was used to measure the surface roughness (Ra) and a spectrophotometer was used for color stability (ΔE00). The EB group had the highest Ra values both before aging (disc: 0.23 ± 0.05, twist: 0.42 ± 0.05) and after aging (discs: 0.28 ± 0.04, twist: 0.46 ± 0.05). The OB group had the highest ΔE00 values before and after aging (discs: 3.06 ± 0.54, twist 3.05 ± 0.41) and the highest after coffee-staining (discs: 3.75 ± 0.70, twist: 3.91 ± 0.57). Re-polishing reduced the ΔE00 values in all materials but did not restore all to clinically acceptable levels. According to the results of this study, it can be concluded that the surface roughness and color stability of resin composites are notably influenced by the polishing technique, aging process, and coffee staining. Specimens that were polished using the multi-stage Super-Snap discs consistently exhibited smoother surfaces across all bulk-fill resin composites compared to those polished with the two-stage Diacomp plus Twist.

Evaluation of Surface Roughness and Microhardness of Bulk-fill and Nanohybrid Composite after Exposure to Different Beverages at Various Time Intervals - An In vitro Study.

The aim of the study was to compare the surface roughness and microhardness of bulk-fill composite and nanohybrid composite resin after exposure to three different beverages at different time intervals. In this study, 60 composite discs each for bulk fill and nanohybrid, of dimensions 10 mm × 2 mm were made. Both composites were randomly divided into four subgroups, i.e., 15 samples each for artificial saliva, tea, coffee, and soft drinks which were further subdivided into five samples for three time intervals. Composite resin discs were immersed in beverages for 4 min in 24 h for 7, 15, and 30 days. All samples were evaluated for surface roughness and microhardness before and after immersion. Both the composites showed a significant increase in surface roughness in all the beverages with maximum change in surface roughness observed in nanohybrid composite resin immersed in soft drinks. Furthermore, the microhardness of both the composites was decreased significantly in all beverages with maximum change in microhardness observed in nanohybrid composite resin immersed in soft drinks. Bulk-fill composite resin has better resistance to surface roughness and higher microhardness as compared to nanohybrid. Furthermore, acidic beverages highly affect the physical properties of both composite resins for longer periods.

Bulk-fill composite in challenging cavities: conversion rate, solubility, and water absorption analysis.

In a deep, curved cavity, polymerization of a bulk fill composite can be challenging. The aim of this study was to investigate the solubility, water absorption, and conversion rate of bulk-fill composite samples prepared using molds with various slope angles. Bulk-fill composite resin (Filtek One Bulk Fill) was placed into cylindrical Teflon molds with a depth of 4mm, angled at varying degrees (90°, 75°, 60°, 45°). Two different LED light-curing units (VALO Cordless, iLed Curing Light) were used to cure the samples. Polymerizations were performed at three different distances (0mm, 2mm, and 4mm). Five samples per group were used, resulting in a total of 24 groups. The Fourier Transform Infrared Spectrometer was utilized to evaluate the conversion levels of the samples. Water sorption and solubility values were determined by storing the composites in distilled water at 37°C for 21days. The VALO light-curing unit applied closest to samples inserted in a 90° angulation mold had the highest mean degree of conversion (41.55%), while iLED light-curing unit group that applied from 4mm to the samples inserted in a 45° angulation mold had the lowest mean conversion (8.97%). The angle of the cavity and the distance at which the light-curing unit is applied significantly affected bulk-fill composite resin conversion. In addition, the choice of light-curing unit impacted the conversion levels. However, with the tested conditions, the water sorption and solubility values of polymerized composite resin samples remain unaffected by these factors.