Beautifil Bulk Research Articles

Preheating effect on microhardness and depth of cure of three bulk-fill composite resins: An in vitro study

ABSTRACT Aim: The aim of this in vitro study was to evaluate and compare the effect of preheating on microhardness and depth of cure of three bulk-fill composite resins. Methods: Three bulk-fill composite resins were used; Group I: Filtek Bulk Fill, Group II: Beautifil Bulk Restorative and Group III: Tetric N Ceram Bulk Fill. Further each group was divided into two subgroups, Sub Group A: Discs were prepared using nonheated composite, Sub Group B: Discs were prepared using preheated composite. A total of 60 disc shaped specimens were prepared and microhardness (Vickers Microhardness Number [VHN]) of the top and bottom surfaces of the disc specimens were measured by Vickers microhardness tester. The ratio of the bottom surface VHN to the top surface VHN was used to calculate the depth of cure. Results: Preheated groups showed higher VHN values as compared to nonheated groups. Group II showed higher VHN value as compared to Group I in both subgroups. Group III showed the least VHN values in both subgroups. VHN values were maximum on top surfaces and minimum on the bottom surfaces for all the groups. It was found that the highest depth of cure was 0.71 while lowest depth of cure was 0.62. Conclusion: Preheating resulted in higher VHN values compared to nonheating. Top surface VHN values were better as compared to bottom surface VHN values for all groups. The depth of cure showed satisfactory results for all groups.

Surface Degradation of Ion-releasing Restorative Materials With Cariogenic Challenge.

This study examined the influence of cariogenic environments on the surface roughness of ion-releasing restorative materials (IRMs). Custom-made stainless steel molds with holes of 5 mm × 2mm were used to fabricate 60 disc-shaped specimens of each of the following materials: Activa Bioactive (AV), Beautifil Bulk Restorative (BB), Cention N (Bulk-fill) (CN), and Filtek Z350XT (FZ) (Control). Baseline surface roughness (Ra) measurements were obtained using an optical 3D measurement machine (Alicona Imaging GmbH, Graz, Austria). The specimens were then randomly divided into five subgroups (n=12) and exposed to 10 ml of the following mediums at 37°C: distilled water (DW), demineralization solution (DM), remineralization solution (RM), pH cycling (PC) and air (AR) (control). Ra measurements were again recorded after one week and one month, followed by statistical evaluations with two-way analysis of variance (ANOVA) to determine interactions between materials and mediums. One-way ANOVA and post hoc Games Howell tests were performed for intergroup comparisons at a significance level of 0.05. Mean Ra values ranged from 0.085 ± 0.004 (µm) to 0.198 ± 0.001 µm for the various material-medium combinations. All IRMs showed significant differences in Ra values after exposure to the aqueous mediums. The smoothest surfaces were observed in the AR for all materials. When comparing materials, AV presented the roughest surfaces for all mediums. All IRM materials showed increased surface roughness over time in all cariogenic environments but were below the threshold value for bacterial adhesion, except for AV 1-month post immersion with pH cycling. Therefore, besides AV, the surface roughness of IRMs did not deteriorate to an extent that it is clinically relevant.

Niobium oxyhydroxide as a bioactive agent and reinforcement to a high-viscosity bulk-fill resin composite.

The present in vitro study incorporated niobium oxyhydroxide fillers into an experimental high-viscosity bulk-fill resin composite to improve its mechanical performance and provide it a bioactive potential. Scanning electron microscopy synthesized and characterized 0.5% niobium oxyhydroxide fillers, demonstrating a homogeneous morphology that represented a reinforcement for the feature. Fillers were weighed, gradually added to the experimental resin composite, and homogenized for one minute, forming three groups: BF (experimental high-viscosity bulk-fill resin composite; control), BF0.5 (experimental high-viscosity bulk-fill resin composite modified with 0.5% niobium oxyhydroxide fillers), and BFC (commercial bulk-fill resin composite Beautifil Bulk U, Shofu; positive control). In total, 10 specimens/groups (8 × 2 × 2 mm) underwent flexural strength (FS) tests in a universal testing machine (Instron) (500N). Resin composites were also assessed for Knoop hardness (KH), depth of cure (DoC), degree of conversion (DC), elastic modulus (E), and degree of color change (ΔE). The bioactive potential of the developed resin composite was evaluated after immersing the specimens into a simulated body fluid in vitro solution and assessing them using a Fourier-transformed infrared spectroscope with an attenuated total reflectance accessory. One-way ANOVA, followed by the Tukey's test (p<0.05), determined FS, DC, KH, and ΔE. For DoC, ANOVA was performed, which demonstrated no significant difference between groups (p<0.05). The high-viscosity bulk-fill resin composite with 0.5% niobium oxyhydroxide fillers showed promising outcomes as reinforcement agents and performed well for bioactive potential, although less predictable than the commercial resin composite with Giomer technology.

Abrasive resistance and microhardness of self-adhesive (Surefil one) and conventional bulk fill composites: An- in vitro study.

Aims and objectives: To evaluate abrasive resistance and microhardness of self-adhesive Surefil one and conventional bulkfill composites Beautifil bulk restorative and Filtek one bulk fill restorative. Materials and Methods: For the abrasive resistance test, thirty composite discs (4 mm hieght×8 mm width) in each group (n=10) were fabricated. GI: Beautifil bulk restorative, GII: Filtek One Bulk fill restorative and GIII: Surefil one self-adhesive. By placing the material in a mold in a single increment then curing. A custom-made toothbrush simulator was employed for wear testing. The samples weighted before and after the brushing to measure the weight loss. For the microhardness test, thirty cylindrical specimens (6 mm× 8 mm) (n= 10) were fabricated to assess the microhardness, top and bottom surfaces were tested using Vicker Hardness test. The results were analyized with a one-way ANOVA test, the post-hoc comparisons were examined in Tukey test. Results: Abrasive Resistance results, Surefil one (9.52gr) and Beautifil bulk (4.16gr) showed an increase in weight after brushing, while Filtek one bulkfill (-0.85gr) showed a decrease in weight.Microhardness test results, Beautifil bulk showed the highest number of VH (74.83) followed by Surefil one (70.61) and Filtek one bulkfill (62.95). Conclusion: Beautifil bulk was more resistant to abrasion in comparison to Surefil one self-adhesive and One bulk fill. The great weight loss was observed in One bulk fill. Great weight gain was observed in Surefil one self-adhesive. Beautifil bulk showed the highest VH number compare to Surefil one self-adhesive and One bulk fill. Filtek one bulk fill showed low resistance and low hardness number. Keywords: Bulk fill, Self-adhesive, Abrasive resistance, Microhardness Composite, Surefil one

The Effect of Food-Simulating Liquids and Thermal Aging on Surface Roughness and Color Stability of Bulk-Fill and Conventional Composites

Objectives: The aim of this study was to evaluate the effect of food-simulating liquids (FSLs) and thermal aging on the surface roughness and color stability of bulk-fill and conventional composites. Materials and Methods: A total of 320 disc-shaped samples were prepared, with 40 samples from each of 4 different bulk-fill composites (Filtek Bulk Fill, X-tra fil, Beautifil Bulk Restorative, and Estelite Bulk Fill Flow), and 4 conventional nano-filled composite resins (Filtek Z550, CeramX SphereTEC one, Admira, and Kalore). The prepared samples were randomly divided into subgroups for exposure to FSLs (ethanol, heptane, citric acid) and thermal cycling (TC) (n=10 per subgroup) for 28 days. Initial profilometric surface roughness measurements (Ra0) of all samples and AFM and SEM analyses of selected samples were followed by exposure to FSLs and TC. After completion of aging protocols, measurements and analyses were repeated to obtain the Ra1 (post-treatment surface roughness), and change in surface roughness (∆Ra1-0) was then calculated. Subsequently, initial color measurement of the samples was conducted using a spectrophotometer, followed by immersion of the samples in a coffee solution for 24 hours. Color measurements were repeated, and color change (∆E) was calculated. Two-way repeated measures ANOVA was used to compare Ra0 and Ra1 values and one-way ANOVA for comparing ∆Ra and ∆E values. Tukey and post hoc tests were employed for pairwise comparisons. The significance level was set at α=.05. Results: While the surface roughness of bulk-fill composites was affected by the protocols applied (p&amp;lt;0.05), conventional composites generally remained unaffected. Bulk-fill composites exhibited greater ΔRa and ∆E values. The highest ∆Ra and ∆E values were observed in the Beautifil Bulk Restorative group, with the greatest discoloration seen after immersion in citric acid. Conclusions: Thermal cycling and immersion in FSLs affect surface roughness and color stability of composite resins depending on the content and structure of the composites.

A Comparative in vitro Investigation on the Impact of Fiber Insertion on Cuspal Deflection of Maxillary Premolars Restored with Various Types of Bulk Fill Direct Composite Restorations

Background: Polymerization shrinkage remains a significant disadvantage that makes the use of direct composite restorations difficult. Objective: To evaluate how well a fiber insert and multiple bulk-fill direct restorations worked on the cuspal deflection of MOD cavities in premolar teeth using a Dino-Lite digital microscope and computer software. Methods: In sixty fresh maxillary first premolars, large MOD cavities were created. Teeth were randomly divided into six groups of ten based on restorative materials. SonicFill®, Beautifil Bulk®, and Filtek® Bulk Fill posterior restoratives were used in groups A1, B1, and C1, whereas groups A2, B2, and C2 used the same bulk composite with E-glass fiber (UFM, Dentapreg). Under a digital microscope, the intercuspal distance between two reference points on the cusp tips was measured before preparation, after preparation, 15 minutes after finishing restorations, and one month following incubation. Results: There was a significant difference between the groups after 15 minutes of restoration, but no significant differences following cavity preparation or one month of incubation. CD values were considerably higher after 15 minutes of restoration in groups restored with bulk fill only. Beautifil Bulk Fill restorative resulted in greater cuspal deflection than the other groups. The CD values in each group were significantly higher 15 minutes after restoration compared to cavity preparation and a month of incubation. Conclusion: Using inserts, cuspal deflection in MOD cavities can be significantly minimized, and stress release usually occurs after water incubation.

Effect of Acidic Beverages on the Hardness, Elastic Modulus and Wear Resistance of Giomer and Nongiomer Bulk-fill Materials.

The aim of this study was to evaluate and compare the effect of acidic beverages on the hardness, elastic modulus, and wear resistance of four different resin-based restorative materials. A total of 128 specimens (10 mm diameter, 4 mm thickness) were prepared from a conventional resin composite (Filtek Z250 [Z250]), a giomer bulk-fill (Beautifil Bulk Restorative [BBR]) and two nongiomer bulk-fill materials (Tetric N-Ceram Bulk Fill [TNC] and SonicFill 2 [SF2]). Each material group was divided into four subgroups (n=8) according to the storage media: artificial saliva (control), orange juice, regular Coke, and sports drink. The experimental specimens were immersed in the solutions for 30 minutes, five times a day for 5 days and kept in artificial saliva for an hour between the immersion periods. Control specimens were stored in artificial saliva for 5 days. The nanoindentation test with a Berkovich diamond tip was used to determine the hardness and elastic modulus before and after the 5-day storage periods. Following the nanoindentation tests, the specimens were subjected to a chewing simulator for 120,000 cycles. The specimens were then scanned with a three-dimensional scanner. The wear resistance was analyzed by measuring the volume and height loss. Specimens were observed by environmental scanning electron microscopy. The statistical analyses were performed by analysis of variance, Tukey HDS test, and paired samples t-test (α=0.05). Z250 showed significantly higher elastic modulus in all groups (p<0.05). After erosive cycles, the greatest decrease in hardness and elastic modulus was observed for BBR. TNC showed higher wear resistance than the other resin-based materials (p<0.05). The BBR specimens immersed in acidic solutions showed higher wear rates than the artificial saliva group (p<0.05). Conventional resin composite showed higher hardness and elastic modulus than bulk-fill materials when exposed to acidic beverages but comparable or lower wear resistance. Degradation due to acidic beverages most affected the mechanical properties of giomer bulk-fill.

Surface roughness evaluation of composite materials polished with one- or multi-step systems

Aim: As the spectrum of composite materials expands in the dental market, it's becoming more challenging to differentiate the structural properties and to find suitable finishing-polishing (f-p) materials. The main goal is to evaluate the impact of one and multi-step f-p systems on the surface roughness (SR) of current composite materials. Methodology: In this study, nanohybrid bulk-fill (Filtek BulkFill Posterior [FBFP]), nanohybrid (Ceram.x One [CXO]), microhybrid (Filtek Z250 [FZ250]), and giomer bulk-fill (Beautifil Bulk Restorative [BBR]) composites were tested. After sample preparation and 24-h storage in 37 °C distilled water, each main group was assigned to one of two groups (n = 10): a one-step (One Gloss-PS) or a multi-step (Sof-Lex) f–p system. SR values (Ra, µm) were measured using a profilometer. Statistical analysis was done using Tukey HSD and ANOVA tests (p &lt; 0.05). Results: FZ250 showed the highest Ra values, regardless of the f–p system used. CXO showed statistically significantly lower SR scores than FZ250 (p &lt; 0.05). There were no significant differences among the Ra values of the one- or multi-step f–p systems for FBFP and FZ250. Both the material and f–p systems had a significant effect on the Ra values separately. Conclusion: FZ250 showed the highest Ra values, and composites polished with the multi-step f–p system exhibited slightly smoother surfaces than those polished with the one-step system. How to cite this article: Ozan G, Berkman M. Surface roughness evaluation of composite materials polished with one- or multi-step systems. Int Dent Res 2022;12(3):165-70. https://doi.org/10.5577/intdentres.2022.vol12.no3.9 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Polymerization and shrinkage kinetics and fracture toughness of bulk-fill resin-composites.

To determine degree of conversion (DC), maximum polymerization rate (RPmax), polymerization shrinkage (PS), maximum shrinkage rate (PS Rmax) and fracture toughness (KIC) of different types of bulk-fill (BF) composites plus the effect of viscosity reduction techniques. BF specimens were created in 2 mm deep molds: SonicFill 3 (SF3), Viscalor (VC), One Bulk Fill (OBF) and Beautifil Bulk (BBR). SF3 was applied via sonic insertion using a SonicFill handpiece (Kerr Corp. USA). Viscalor was pre-heated in a Caps Warmer in T3 mode (at 68 °C) for 30 s (T3-30 s) and 3 min (T3-3 min), respectively. Specimens were irradiated at zero distance from the upper surface with an Elipar S10 LED unit (3 M ESPE, USA) of mean irradiance 1200 mW/cm2 for 40 s. Real-time polymerization kinetics and DC at 5 min and 24 h post-irradiation (DC5 min and DC24 h) were measured using ATR-FTIR (n = 3). PS was measured up to 1 h on 1 mm thick discs via the bonded-disk technique (n = 3) and PS Rmax obtained by numerical differentiation (n = 3). For fracture toughness, single-edge-notched specimens (32 × 6 ×3 mm) of each BF composite were prepared and measured by three-point bending after 7 d water storage (n = 5). Data were analysed using One-way ANOVA, independent T-tests and Tukey post-hoc tests (p < 0.05). SF3 showed the significantly highest DC5 min, DC24 h and RPmax (p < 0.05), followed by OBF (p < 0.05). Regardless of pre-heating, VC showed comparable conversion kinetics to BBR (p > 0.05). There was no significant difference in PS of these BF composites, except OBF had the highest PS (p > 0.05). However, PS Rmax significantly varied among materials (p = 0.047) and SF3 had the highest PS Rmax. Regarding fracture toughness, BBR had the lowest KIC (p < 0.05), whereas other composites showed similar KIC (p > 0.05). Strong correlations of filler content (wt%)-PS/KIC were found. Different pre-heating times had no significant influences on DC %, RPmax, PS, PS Rmax and KIC of VC (p > 0.05). Different types of bulk-fill composites showed comparable shrinkage. A highly filled BF giomer composite (BBR) had the lowest fracture toughness, whereas others had similar KIC. Pre-heating had no adverse effects on Viscalor properties. Sonication and pre-heating are beneficial techniques to enhance composite flowability without either increasing shrinkage or reducing fracture toughness.

Effect of a fiber-reinforcing technique for direct composite restorations of structurally compromised teeth on marginal microleakage.

To evaluate if the marginal microleakage of extensive Class I composite resin restorations can be affected by applying ultra-high-molecular-weight polyethylene (UHMWPE) fibers with the wallpapering technique combined with different restorative materials and methods. A 120 human molars were selected and one extensive Class I cavity was prepared on the occlusal surface of each tooth. The specimens were divided into 12 groups (n=10) according to the type of restorative material (Filtek Z550, Beautifil II LS or Beautifil Bulk Restorative), the use or not of reinforcing fibers (ribbond) and the applied restorative technique (incremental or bulk). The specimens were subjected to thermocycling and then immersed into a 50 wt% silver nitrate solution following a dying protocol. Subsequently, the teeth were prepared for SEM observations to evaluate the extent of marginal microleakage. Three-way ANOVA revealed that the type of material, the use of ribbond fibers and the type of restorative technique significantly affected marginal microleakage (p < 0.001). Application of ribbond fibers decreased marginal microleakage to all tested restorative materials, regardless of the restorative technique, in a range of 31.2-81.4%. In the groups with no-use of ribbond fibers, among the materials there were no significant differences in microleakage when the teeth were restored with the incremental technique (p > 0.05). The use of UHMWPE fibers with wallpapering technique in Class I composite restorations may be an effective method to reduce marginal microleakage, regardless of the selected restorative technique or the material. Clinicians may be encouraged to utilize reinforcing fiber restorative techniques for direct restorations of structurally compromised teeth as a valid alternative to indirect restorations.

Color changes in bulk-fill resin composites as a result of visible light-curing.

We evaluated twelve commercially available bulk-fill resin composites to determine the colorimetric changes that occurred as a result of the photo-polymerization reaction. Samples of the resin composites were prepared as disks 8 mm in diameter and 3 mm in thickness. A colorimeter was used to measure the color of samples on a black background before and after the polymerization processed had been initiated. As results, each of the photo-initiated bulk-fill resin composites tested except for Beautifil Bulk A showed a significant color difference more than that of conventional resin composites. Bulk Base Flow became darker, whereas Beautifil Bulk Flow became clearly lighter. All resin composites except for Bulk Base Flow became less yellow. Thus, Beautifil Bulk A exhibited the least color change among all the bulk-fill resin composites. However, this color change showed a marked change (NBS units) as observed by the human naked eye.

Giomer composite compared to glass ionomer in occlusoproximal ART restorations of primary molars: 24-month RCT.

Occlusoproximal restorations of primary molars usually fail, so it is necessary to investigate new materials that may overcome this challenge. Thus, this trial aimed to evaluate the longevity of occlusoproximal ART restorations in primary molars using a glass ionomer cement - GIC (Equia Forte® - GC Corp) and a Giomer resin composite - GCR (Beautifil Bulk Restorative® - Shofu Inc) after 24 months. One hundred and eighty-two (182) children aged from 4 to 8 years were selected and randomly assigned to GIC or GCR. A paediatric dentist treated them in the school setting in Cerquilho, Brazil, and the restorations were assessed after 3, 6, 12, 18 and 24 months. The primary outcome was the restoration survival, evaluated using the Kaplan-Meier and superiority Cox regression analyses. Intention to treat (ITT) was performed as a sensitivity analysis using superiority test P value and confidence interval (CI = 95%). Independent variables included gender, age, molar, jaw, cavity volume and caries experience. The restoration survival after 24 months was GIC = 58.1% and GCR = 49.1% (HR = 1.24; CI = 0.97-1.59). ITT analysis showed a success of GIC = 61.1% and GCR = 52.2% (RR = 1.17; CI = 0.91-1.52). The superiority hypothesis was not proved in both analyses (P > 0.05). GCR does not have superior longevity than GIC in occlusoproximal ART restorations of primary molars.

Cytotoxic Effects of Bulk-Fill Composites on L929 Fibroblast Cells

Objective: Unlike traditional composite resins, bulk-fill composite resins could be polymerized as thicker layers. This study aims to contribute to the field by investigating the cytotoxic effects of various bulk-fill composite resins on L929 mouse fibroblast cells in vitro. Material and Methods: In our study, six bulk fill and one conventional composite resin were used. Composite resin samples (8×4 mm) were prepared in a sterile cabinet by using a glass mod and polymerizing with a led light device (DTE LUX E, Germany). Composite samples (n:3) of which surface area was calculated according to ISO 10993-12: 2012 standards (3 cm2/ml), were kept in media for 24 h and 72 h in 37 oC incubator, their extracts were filtered in 1:1 and 1:2 proportion and were added on L929 mouse fibroblast cells. Cell viability was examined by the MTT assay and cell death by the LDH test. Cell viability results were evaluated using one-way analysis of variance (ANOVA) test (p&lt;0.05). Results: When the 1:1 extracts from 4 mm thick bulk-fill composite samples were applied on L929 mouse fibroblast cells, cell viability rates showed significant differences compared to the control group at the end of 24 h and 72 h (except for Estelite Bulk Fill Flow). Although the extracts of the tested composite samples at 1:1 and 1:2 ratio at the end of 72 hours caused a decrease in L929 mouse fibroblast cell viability, the cell viability rate of only PRG-containing bulk fill composite and conventional composite remained below the cell viability ratio (70%) specified in ISO standards. Bulk fill composites did not produce toxic effects (except Beautifil Bulk Restorative) according to the LDH test. Conclusions: Despite decreasing in general the cell viability, bulk-fill composite resins used in 4 mm thick layers provided cell viability rates over the acceptability level, except PRG-containing bulk fill composite (Beautifil Bulk Restorative), which was cytotoxic to L929 mouse fibroblasts. Keywords Bulk fill composite; Cytotoxicity; L929 cells; LDH assay.

Effect of layer thickness on residual monomer release in polymerization of bulk-fill composites

The aim of the present study was to investigate and compare the quantity of residual monomers leached from the bulk-fill composites with different compositions polymerized at varying layer thickness. Three bulk-fill (X-tra-fil, Beautifil Bulk Restorative, Fill-Up) and a nanohybrid composite (Filtek Z550) were used for the study. The composite resin samples were prepared with a stainless steel mold. For each composite, two groups were constructed. The samples in the first group were prepared using the 2 + 2 mm layering technique. In the second group, the composite samples were applied as a 4 mm-thick one layer and polymerized. Then, each composite samples were kept in a 75% ethanol solution and residual monomers released from composite resins were analyzed with an HPLC device after 24hour and 1 month. The data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. Except the Fill-Up, all of residual monomer elution from the bulk-fill composites was significantly affected by the layer thickness (p &lt; 0.05). The greatest monomer release was detected at 1 month after polymerization as a single 4 mm layer for Beautifil Bulk Restorative. Fill-Up composite showed similar residual monomer release in polymerization at different layer thicknesses compared to other composite resins. In the 2 + 2 mm layering technique, the least monomer elution was detected in the Filtek Z550 composite group. While Bis-GMA was the most released monomer in X-tra fil composite, UDMA was the most released monomer in all other composite resins. During polymerization of the bulk-fill composite, the layer thickness of the composite applied may affect the amount of residual monomers released from the composite resins. Conventional composites may release less monomer than bulk-fill composites when used with layering.

Evaluation of Cusp Deflection in Teeth Restored with Various Manipulation Techniques and Types of Composite Restorations

This study aim to evaluate and compare the deflection of premolar teeth cusps that filled incrementally withconventional composite (Universal Ceram X One Sphere TEC TM) and various types of bulk fill compositematerials (Kerr SonicFillTM3 , 3M FiltekTM Bulk Fill and Shofu Beautifil Bulk Fill). In this study 40 human,healthy maxillary first premolars were collected and large MOD cavity were prepared in them . Accordingto restorative materials, the teeth were haphazardly categorized in 4 groups (n=10 per group). Group I :The teeth were filled with SonicFill™3 Kerr composite, Group II : The teeth were filled with Filtek BulkFill, Group III : The teeth filled with Shofu Beautifil Bulk Fill composite, and Group IV : The Teeth werefilled with Dentsply Ceram X One Sphere TEC TM. By the aid of digital microscope intercuspal distance onthe tips of the cusps between two index reference points was measured pre preparation of the cavity , postpreparation, after 15 minutes of completion of fillings. The cuspal deflection was calculated by determinationof the changes in measurements. Inward cuspal deflection was occurred in all teeth after filling , minimalcuspal deflection reported in all study groups that filled with bulk fill filling in comparison with group IV thatfilled in layering technique with conventional composite. Greater cuspal deflection produced by BeautifilBulk Fill restorative in comparison with other groups. As a conclusion of this study that using of new bulkfilling restorative materials could dramatically minimize cuspal deflection.

The effect of light curing intensity on bulk-fill composite resins: heat generation and chemomechanical properties

Objectives The aim of this study was to assess the effect of light curing intensity and wavelength spectrum on heat generation and chemomechanical properties of bulk-fill composites. Methods Four bulk-fill restorative materials (Filtek bulk-fill, Tetric PowerFill bulk-fill, Beautifil Bulk restorative and Admira Fusion X-tra were used in this study. A total of 100 cylindrical specimens of each composite (n = 25/group) were prepared, then cured using monowave light curing unit (LCU) with a single light intensity of 1470 mW/cm2, and polywave LCU with three different light intensities (1200,2100, 3050mW/cm2). The temperature change during polymerisation was measured by five K-type thermocouples placed in each 1 mm layer from top to bottom. Hardness and degree of conversion of composites at each level were evaluated. Results were statistically analysed. Results The use of polywave LCU resulted in statistically higher peak temperatures ranging between 31.4–63.5 °C compared to the temperature generated by monowave LCU ranging between 29.5–60 °C (p < .05). Curing using polywave LCU with the highest light intensity of 3050 mW/cm2 caused the highest peak temperature irrespective of the composite types. There was no significant difference in hardness with different light curing intensities and curing times, regardless of the bulk-fill resin materials (p > .05). A positive correlation was also found between the hardness and the DoC of the four bulk-fill composites. Conclusion The change in temperature during polymerisation of bulk-fill composites were found to be proportional to the increase in light curing intensity. Mechanical properties of the bulk-fill composites were dependent on the composition and the type of photoinitiators.

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.

Effect of surface sealant on the surface roughness of different composites and evaluation of their microhardness.

The aim of this study was to evaluate the effect of a surface sealant on the surface roughness of different composites and compare their microhardness values. Sixty disc-shaped specimens were prepared and assigned to 6 groups (n =10). Groups were prepared as follows; Group 1 (Herculite XRV Ultra), Group 2 (Beautifil Bulk Restorative) and Group 3 (Filtek Bulk Fill Posterior Restorative). Groups 4, 5, and 6 were prepared by applying a surface sealant (BisCover LV) on the specimens in groups 1, 2 and 3. Surface hardness of the discs in group 1, 2, and 3 and surface roughness of the discs in all groups were measured using the Vickers hardness test and a profilometer, respectively. One-way ANOVA was used to test for differences among the groups. No significant differences were observed in the microhardness and roughness between the experimental and control groups for each restorative materials. Group 3 showed the highest surface hardness and group 4 showed the lowest surface roughness values. Using the BisCover LV resin after the polishing step has no significant effect on the surface roughness. The highest hardness values were obtained for the Filtek Bulk Fill Posterior Restorative after the polishing step. The smoothest surfaces were obtained for all experimental groups using the BisCover LV resin after the polishing step, Herculite XRV Ultra showed lower average roughness values than the other materials.

Surface properties and bacterial adhesion of bulk-fill composite resins

ObjectivesThe aim of the present study was to evaluate the Streptococcus mutans and Streptococcus mitis adhesion and related surface properties of bulk-fill resin composite. MethodsFour novel bulk-fill composite with different composition were used; Sonic Fill-2 (KSF), Filtek BulkFill (FBF), Admira Fusion X-tra (AFX), Beautifil Bulk Restorative (SBB) and a control group (glass) were included in the study. After standardized surface polishing procedure, surface properties of composite specimens were evaluated using surface roughness (SR) measurements by a profilometer, hydrophobicity and surface free energy (SFE) analyses, elemental and topographic analyses by SEM-EDS. To evaluate the bacterial adhesion, composite specimens were immersed in artificial saliva and mucin for pellicle development. After 1-h immersion, bacterial suspension was added to the pellicle-coated specimens, which were incubated at 37 °C in 5% CO2 atmosphere for 24 h. Adhered bacteria counts were determined as x108 Cfu/ml. Bacterial adhesion was also investigated using confocal laser scanning microscopy. ResultsNo statistically significant differences were found among bulk fill composites in terms of surface roughness while glass showed the lowest Ra values. The lowest contact angle values were found in the control group and Sonic Fill-2 while the highest SFE values were observed in these materials. No statistically significant differences were found between the S. mutans counts. For S. Mitis adhesion, the highest value was found in Sonic Fill-2 and no significant differences were observed between the other groups. ConclusionsSR of bulk-fill composite resins had no effect on bacterial adhesion. However, bacterial adhesion increased with higher SFE values. Clinical significanceAlthough the surface roughness of composites used in the study is similar, in clinically, S. mitis adhesion may be more in the KSF group because of high surface free energy.

Depth-Dependent Cellular Response from Dental Bulk-Fill Resins in Human Dental Pulp Stem Cells.

The proper choice of dental composite resins is necessary based on the minimal cytotoxicity and antiodontogenesis on human dental pulp stem cells for dental pulp-dentin tissue repair and regeneration. The aim of this study was to evaluate the cytotoxicity and antidifferentiation effects of dental bulk-fill resins, able to be polymerized as a bulk status for filling deep cavity of a tooth by single light curing, against human dental pulp stem cells (hDPSCs) from three compartments corresponding to depth (0-2, 2-4, and 4-6 mm) from the light-curing site. Three bulk-fill composite resins (SDR, Venus bulk-fill (VBF), and Beautifil Bulk Flowable (BBF)) and a conventional flowable composite resin (Filtek Z350 XT flowable restorative (ZFF)) were individually filled into a cylindrical hole (h = 2 mm, Ф = 10 mm), and three compartments (total ~6 mm of height) were combined as a single assembly for light curing. The resin samples from the three layers were separated and eluted in the culture medium. The extracts were exposed to hDPSCs, and cytotoxicity and differentiation capability were evaluated. Depth of cure and surface hardness according to depth were determined. All bulk-fill resins except BBF revealed cytotoxicity from 4 to 6 or 2 to 4 mm, while ZFF was cytotoxic at over 2 mm. Depth of cure was detected from 3.55 to 4.02 mm in the bulk-fill resins (vs. ~2.25 mm in conventional resin), and 80% hardness compared with that of a fully polymerized top surface was determined from 4.2 to 6 mm in the bulk-fill resin (vs. 2.4 mm in conventional resin). Antidifferentiation was revealed at a depth of 4-6 mm in the bulk-fill resin. There was a difference in depth of cytotoxicity and antidifferentiation between the bulk-fill composite resins, which was mainly due to different cure depths and ingredients. Therefore, careful consideration of choice of bulk-fill resins is necessary especially for restoration of deep cavities for maintaining the viability and differentiation ability of dental pulp stem cells.