Filtek Z250 Research Articles

Impact of adhesive application errors on dentin bond strength of resin composite

Objectives: To investigate the impact of adhesive application errors on dentin bond strength of resin composite. Material and Methods: 165 extracted permanent human molars were ground to mid-coronal dentin. The dentin specimens were treated with one of three adhesive systems (OptiBond FL, Clearfil SE, Scotchbond Universal) either according to manufacturer’s instructions or with systematic errors in the application procedure and before application of resin composite (Filtek Z250). After storage (37 °C, 100% humidity, 24 h) shear bond strength (SBS) was measured and data analysed with either one-way ANOVA followed by Tukey tests (OptiBond FL, Scotchbond Universal, control groups) or Kruskal-Wallis followed by Wilcoxon tests (Clearfil SE). Finally, the failure mode of all specimens was assessed. Results: With OptiBond FL and Clearfil SE omitted application (p ≤ 0.0001) as well as no evaporation (p ≤ 0.001) of the solvents in the primer significantly reduced the SBS. Omitted application of the adhesive, respectively the bond, had a negative influence on the SBS of Clearfil SE (p < 0.0001), but not of OptiBond FL (p = 0.776). With Scotchbond Universal, no evaporation of the solvents (p < 0.0001) as well as no light-cure (p = 0.0004) had a significant negative influence on the SBS. Using the adhesive systems according to manufacturer’s instructions, Clearfil SE achieved significantly lower SBS than OptiBond FL and Scotchbond Universal (p = 0.0027). Adhesive failure at the dentin surface was generally the most frequent failure mode observed. Conclusion: All three adhesive systems tested were sensitive to application errors. For optimal result and longest possible durability of resin restorations, clinicians should strictly adhere to the manufacturer’s instructions.

Dentinhaftung bioaktiver Füllungsmaterialien für die Kinderzahnheilkunde

Aim: Bioactive materials are of interest for dental restoration in children with high caries risk. An important parameter for clinical success is durable adhesion to tooth hard tissues. Therefore, the present study evaluated dentin bonding behavior of two bioactive materials (ACTIVA BioACTIVE-RESTORATIVE [Acti, Pulpdent, Watertown, MA, USA] using All Bond Universal [BISCO, Schaumburg, IL, USA], and Cention N bonded with Adhese Universal [Cent, Ivoclar Vivadent, Schaan, Liechtenstein]) compared to a bonded resin composite (Filtek Z250 [FZ250, 3M Oral Care Dental Products, St. Paul, MN, USA] with OptiBond FL [Kerr, Biberach, Deutschland]) and a conventional glass ionomer cement (Fuji Triage pink [FTp, GC Corporation, Tokyo, Japan]) using Cavity Conditioner (GC Europe, Löwen, Belgien).Materials and methods: Twenty-eight caries-free third molars were randomly assigned to four groups (n = 7). Crowns were ground flat to expose dentin. Specimens were pretreated according to the manufacturers' instructions and built-up in 0.5-2 mm layers with composite. After storage (24 h at 37 °C in distilled water), specimens were cut into resin-dentin beams (0.36 mm2 for Acti, Cent, and FZ250; 1 mm2 for FTp) and subjected to microtensile bond strength testing. Additional micromorphological analyses were done using both light and scanning electron microscopy. Statistical appraisal was carried out using one-way analysis of variance (ANOVA; modified least significant difference [LSD] test; p <0.05). Results: Dentin bond strengths were (in MPa, numbers I-III indicate significant differences between groups): FZ250: 63.9 ± 8.3 (I); Acti: 52.1 ± 8.2 (II); Cent: 51.4 ± 10.9 (II); FTp: 3.7 ± 0.9 (III). A pronounced hybrid layer was only found in FZ250. The investigated bioactive restorative materials showed lower dentin adhesion compared to the bonded resin composite, but 13-fold higher values than the GIC (FTp).Conclusion: When adhesively bonded, the bioactive materials under investigation exhibited good dentin bonding behavior. In minimally invasive restorations, we recommend using them with a separate bonding step. However, further studies must show whether this impairs the caries-inhibiting, bioactive effect of the materials.

Depth of Cure, Mechanical Properties and Morphology of Dual-Cure Bulk-Fill Composites

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

Effects of Accelerated Aging on Color Stability and Surface Roughness of a Biomimetic Composite: An In Vitro Study.

The aim of this in vitro study is to compare the color stability and surface roughness of conventional and self-blending resin composites before and after staining and aging. Three conventional composites (Filtek Z350, IPS Empress Direct, and Estalite Palfique LX5) and one self-blending (Omnichroma) resin composite were used in this study. Sixty discs were prepared and polymerized in a metal mold (n = 15 per group). Samples were then finished and polished by Layan discs. Color testing and roughness testing were measured as a baseline (T0) by a spectrophotometer and profilometry. Samples were then stained with tea for 24 h, water aged for 30 days, and then a second reading (T1) was performed. Finishing and polishing were performed again, and a third reading (T2) was collected. All groups showed significant decrease in all color parameters (L*, a*, and b*); however, after polishing, all groups showed color enhancements matching pre-experiment baseline colors in all color parameters (L*, a*, and b*), except for Estelite Palfique LX5, which showed a significant difference in L relative to the baseline. Furthermore, Estalite Palfique LX5 showed increased roughness after staining compared to the baseline, unlike other groups. No significant differences in color stability were found between self-blending composites and other composite materials. Accelerated aging and staining had minimal effects on the surface roughness of self-blending composite.

Development of functional fillers as a self-healing system for dental resin composite

ObjectivesTo evaluate the incorporation of repairing capsules containing different monomers and polymerization modulators on the self-healing efficiency of an experimental photopolymerizable resin-based composite. MethodsSelf-healing capsules containing different monomers and polymerization modulators were prepared by emulsion polymerization: TCDHEPT (TEGDMA and DHEPT), BTCDHEPT (Bis-GMA, TEGDMA, and DHEPT), and BTCBPO (Bis-GMA, TEGDMA, and BPO). The capsules were analyzed through Fourier transform infrared spectroscopy and scanning electron microscopy. The capsules were added into experimental photopolymerizable resin composites establishing the following groups: ER (Control without capsules), ER+BPO, ER+BPO+TCDHEPT, and ER+BTCBPO+BTCDHEPT. Filtek Z350 resin composite (3 M ESPE) was used as a commercial reference. The materials were tested for degree of conversion (DC), flexural strength (σf), elastic modulus (Ef), fracture toughness (virgin KIC), self-healing efficiency (healed KIC), and roughness. For statistical analysis, the significance value was established at an a = 0.05 level. ResultsWhen compared to the control material, the incorporation of repairing capsules did not affect DC, σf, and Ef. Fracture toughness was statistically similar between the experimental groups (p ≤ 0.05). Healed KIC was statistically different between the groups ER+TCDHEP and ER+BTCBPO+BTCDHEPT; the self-healing efficiency was higher for ER+TCDHEPT. Surface roughness was statistically similar among all groups. ConclusionsThe use of self-healing capsules promoted repair of the material. Studies with material aging after the self-healing process are necessary to better demonstrate the effectiveness of this system. Clinical significanceThe self-healing system seemed to be a promising technology to be used in self-repaired restorative materials, which may prevent restoration fractures.

Comparative evaluation of fracture resistance of posterior teeth restored with recent composite resins

Aim: Comparative evaluation of the fracture resistance of maxillary molar teeth restored with recent composite resins. Materials and Methods: Fifty freshly extracted molar teeth were selected. Ten specimens served as control –unrestored, unprepared, intact (Group 1). Mesio-occluso-distal cavity preparation was prepared on the rest of the specimens. These specimens were further divided into four groups: prepared but unrestored (Group 2), teeth restored with with Nano hybrid composite (Tetric N-Ceram, Ivoclar Vivadent). (Group 3), teeth restored with Micro hybrid composite (Polofil supra). (Group 4), and teeth restored with Nano filled composite (Filtek Z-350). (Group 5). The specimens were then subjected to compressive axial load using universal testing machine. Data were analyzed using data were analyzed using Statistical package for social sciences software (SPSS v 20.0, IBM Corp.) Results: The positive control group exhibited highest fracture load (377±63.8 Kg-force). There was less difference seen in between the all recent composite resins (P &gt; 0.05). There is significant difference noted in fracture load between control group and treatment groups Conclusion: Type of the composite restoration makes little difference in the fracture toughness while restoring MOD cavities.

Effect of different polymerization times on color change, translucency parameter, and surface hardness of bulk-fill resin composites.

Polymerization plays an important role in the optical and mechanical properties resin composite materials. The current study aimed to evaluate the effect of different polymerization times on the color change, translucency parameter (TP), and surface hardness of resin composites after thermocycling. Microhybrid resin composite (Filtek Z250; used in the control group) and bulk-fill resin composites (Filtek One Bulk-Fill Restorative, Tetric EvoCeram Bulk-Fill, and Tetric N-Ceram Bulk-Fill) were used. Each bulk-fill composite was placed as a single layer. Polymerization of the bulk-fill composites in the first group was completed in 20 s, and that in the second group was completed in 40 s (n = 10). Filtek Z250's polymerization was completed with 2 mm (20 s) + 2 mm (20 s). The color change (ΔE00) and translucency parameter (TP00) were calculated using the CIEDE2000 formula. Before and after thermocycling, the TP and surface hardness values were measured. The data were analyzed using one- and two-way analysis of variance, paired-samples t-test, and Tukey's test (P < 0.05). After thermocycling, the ΔE00 values of the resin composite samples were 1.66-2.56. Compared to the control group, the Filtek One Bulk-Fill 20 s group exhibited the lowest color change values. The Filtek Z250 group exhibited lower TP and significantly higher microhardness values than the other bulk-fill resin groups before and after thermocycling (P < 0.05). There were no observed differences in the Tetric N-Ceram and Tetric EvoCeram groups before and after thermocycling. Under the conditions of 10,000 thermal cycles, different curing times did not affect the color change and hardness values of the bulk-fill materials. However, differences were observed among the composite materials. After thermocycling, the surface hardness and TP values decreased in all the resin composites. Depending on the material content, effective results can be obtained from the 20 s polymerization of bulk-fill resin composites.

Evaluation of microleakage and push-out bond strength of various composite resins for sealing the screw-access channel in implant-supported restorations

Statement of problemMicroleakage and loss of the composite resin sealing the screw-access channel are frequent complications of screw-retained implant-supported prostheses. How the screw-access channel should be best restored to reduce such complications is unclear. PurposeThe purpose of this in vitro study was to evaluate the microleakage and bond strength of 3 types of composite resins (flowable, packable, and bulk-fill) with or without a bonding agent treatment to seal the screw-access channel of 2 types of restorative materials (zirconia and Co-Cr alloy) with or without thermocycling. Material and methodsIn total, 240 yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) specimens (IPS e.max ZirCAD) and 240 Co-Cr alloy (Vera PDS) specimens were prepared with a Ø3×3-mm cylindrical cavity at the center to simulate the screw-access channel. Three types of composite resins (flowable, packable, and bulk-fill resin) (Filtek Z350 XT Flowable Restorative, Filtek Z350 XT Universal Restorative, and Filtek One Bulk Fill Restorative) were applied to restore the access channel of the zirconia and Co-Cr specimens with or without a bonding agent (Single Bond Universal Adhesive). Microleakage and push-out bond strength were determined and compared by dividing the specimens into experimental groups with or without thermocycling (1000 times with 30 seconds at 5 ±2 °C and 55 ±2 °C). The results were analyzed by using a 1-way ANOVA and 4-way ANOVA. Adjustment for multiple comparisons was made with the Tukey Honestly Significant Difference (HSD) test. ResultsThe specimens subjected to thermocycling showed a lower bond strength (P<.001) and higher microleakage (P<.001) than specimens stored in a constant-temperature water bath. Specimens treated with bonding agents showed a higher bond strength (P<.001) and lower microleakage (P<.001) than specimens not treated with a bonding agent. Higher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin (P<.001). Packable resin showed higher microleakage than flowable resin and bulk-fill resin (P<.05). No significant difference in microleakage was found between the flowable resin and bulk-fill resin (P>.05). ConclusionsHigher bond strengths were observed in the order of bulk-fill resin, packable resin, and flowable resin. Less microleakage was observed in the flowable resin and bulk-fill resin than in the packable composite resin. Bonding agent treatment was effective in increasing bond strength and decreasing microleakage. Zirconia and Co-Cr showed a bond strength similar to that of composite resins, but zirconia showed higher microleakage than Co-Cr. Restoring the screw-access channel with the bulk-fill resin should increase bond strength and reduce microleakage.

Evaluation of the Color Stability, Water Sorption, and Solubility of Current Resin Composites.

This study aims to assess the color stability, water sorption, and solubility of 11 resin composites as commercially available dental products. Twenty samples (10 mm in diameter and 2 mm in thickness) of each material were fabricated using a customized silicone mold, followed by immersion in each of curry, coffee, wine, and distilled water for 28 days (n = 5). Baseline shade and color changes (ΔE) were measured using a reflection spectrophotometer. The CIE L*, a*, b* system was used to evaluate the color changes. Five samples of each resin composite were applied to test water sorption and solubility according to ISO 4049:2009. As a result, the ∆E values were significantly influenced by each of the three factors (composition of material, solution, time) and the interactions between them (p < 0.001). Highest resistance to discoloration was achieved by Ceram.X One Universal (CXU), followed by Magnafill Putty (MP). Generally, microhybrid composites showed fewer color changes than nanohybrid composites and giomers. DX. Universal and Filtek Z350 XT showed the highest ΔE values in all colorants. All materials tested in this study fulfilled the criteria of ISO 4049:2009; CXU and MP had the lowest water sorption and solubility. The Pearson test showed statistically significant positive correlations between water sorption and ΔE and between solubility and ΔE.

Effect of Rapid Polymerization on Water Sorption and Solubility of Bulk-fill Composites.

The aim of the study was to examine the impact of rapid high-intensity polymerization on water sorption and solubility of a new generation of bulk-fill composite materials. Five materials were tested: a conventional composite Filtek Z250 (3M, St. Paul, USA) and four bulk-fill composites, Filtek One Bulk Fill (3M), Tetric PowerFill (Ivoclar Vivadent, Schaan, Liechtenstein), Tetric PowerFlow (Ivoclar Vivadent), SDR Plus (Dentsply, Konstanz, Germany). Composite specimens with a 9-mm diameter and a 2-mm height (n = 6) were polymerized with a high-intensity curing unit (Bluephase® PowerCure, Ivoclar Vivadent). The control group was polymerized for a total of 40 s on both sides (1193 mW / cm2) and 3s group for 3 s on one side (3053 mW/cm2). Water sorption and solubility were measured by ISO 4049 method up to 30 days of immersion. The results were statistically analyzed using one-way ANOVA with Tukey post-hoc correction. Different polymerization protocols for the same material were compared by t-test (p <0.05). The 3s polymerization protocol increased the solubility of all materials. Filtek One Bulk Fill showed the highest water sorption and solubility values, and Tetric PowerFlow proved to be a stable material with low values of tested parameters. During immersion, a saturation of specimens was achieved in low-viscosity bulk-fill composites within two weeks, while in other materials it was not achieved within 30 days, or more, following the immersion. Rapid polymerization caused an increase in solubility, which could affect the biocompatibility of the investigated materials not intended for the 3s curing. SDR Plus and Filtek One Bulk Fill should not be polymerized with rapid high-intensity curing due to increased solubility that exceeds ISO 4049:2009 limits.

Yeni geliştirilen bir kompozit rezin materyalinin bükülme dayanımının karşılaştırılmalı olarak değerlendirilmesi: Bir in vitro çalışma

Amaç: Bu in vitro çalışmada Mikrohibrid doldurucu içeriği ile yeni geliştirilen bir dental kompozitin mekanik özelliklerinden bükülme dayanımının iki farklı mikrohibrit dolduruculu kompozit materyal ile karşılaştırılmalı olarak değerlendirilmesi amaçlanmıştır.&#x0D; Gereç ve Yöntem: Mevcut çalışmada, yeni üretilen bir Üniversal Kompozit (Dolgunn, Himg Seramik ve Medikal Kompozit San.Tic. Ltd.Sti, Türkiye) ile 2 farklı mikrohibrit kompozit (G- aenial Anterior, GC-Japonya ve Filtek Z250 3M, USA) kullanıldı. Her bir dolgu materyalinden 10 adet dikdörtgenler prizması şeklinde (2x2x25 mm boyutunda) örnekler hazırlanarak, instron test cihazında 1 mm/dk hızda bükülme dayanım değerleri ölçüldü. Verilerin istatistiksel analiz için Kruskal-Wallis testi kullanıldı. Tüm testler için istatistiksel anlamlılık düzeyi p=0.05 alındı.&#x0D; Bulgular: Tüm test materyalleri arasında bükülme dayanımları açısından istatistiksel olarak anlamlı farklılıklar gözlendi (p

In Vitro Evaluation of Gastric Acid and Toothbrushing Effect on the Surface State of Different Types of Composite Resins.

Background and Objectives: The aim of this in vitro study was to evaluate the effect of gastric acid associated with the effect of toothbrushing on the surface roughness of different types of composite resin used for direct restorations. Materials and Methods: The materials used in this study were two microhybrid (Filtek Z250, Herculite XRV) and two nanohybrid (Filtek Z550, Herculite XRV Ultra) composite resins. Two hundred and forty cylindrical samples with a height of 2 mm and a diameter of 6 mm were divided into four groups (groups A, B, C and D) corresponding to each tested material (n = 60). Each group was divided in two subgroups: subgroup I—the samples were submersed in hydrochloric acid and immediately submitted to toothbrushing; subgroup II—the samples were submitted only to toothbrushing. The simulation of the acid attack was performed by immersing the samples in a 0.01 M hydrochloric acid solution for 90 min. This procedure was followed immediately by toothbrushing simulation with 10,000 cycles. The acid attack and toothbrushing simulation were performed for two times. The surface roughness evaluation was performed with a Proscan 2100 profilometer. Repeated Measures ANOVA and Bonferroni post-hoc tests were used to perform the statistical analysis. Results: Simulation of one year of toothbrushing associated or not to hydrochloric acid exposure increases the surface roughness of microhybrid and nanohybrid composite resins. Six months of toothbrushing associated to six months of hydrochloric acid exposure increase the surface roughness of nanohybrid composite resins. Conclusions: Microhybrid composite resins surface becomes rougher after toothbrush and acid submersion when comparing to nanohybrid composite resins.

Comparison of polymerization shrinkage of a new bulk-fill flowable composite with other composites: An in vitro study.

Since composites still face a critical problem called polymerization shrinkage and bulk-fill composites have reported acceptable results for this issue, this study aims to assess the polymerization shrinkage of a new bulk-fill flowable composite (G-aenial bulk injectable [GBI]) and compare it to other bulk-fill and conventional composites. In this in vitro study, 25 composite discs were fabricated using three bulk-fill and two conventional composites. They were bonded to a microscopic slide and were covered by a coverslip. This assembly was transferred to a linear variable differential transformer and composite samples were cured from underneath the slides. Dimensional changes formed in composite samples were recorded. Data were analyzed using analysis of variance followed by post hoc Tukey's and Dunnett's tests. The groups were significantly different regarding polymerization shrinkage. G-aenial bulk injectable and G-aenial universal flo showed significantly higher polymerization shrinkage than other composites at 30, 60, and 1800 s after light irradiation, while X-tra fil and Filtek Z250 showed the lowest polymerization shrinkage at the aforementioned time points. According to the results, the new composite had polymerization shrinkage similar to the conventional one. Bulk-fill composites reported similar or lower shrinkage to conventional composites.

Energy drinks alter the surface morphology and roughness of composites, fissure sealants and titanium: An in vitro study

ObjectivesThe influence of energy drinks on dental materials are relatively under addressed. Our aim was to investigate the effect of energy drinks on dental materials used intraorally in young individuals. Commonly used preventive, restorative, and orthodontic materials were tested in vitro. MethodsThe effect of two commercially available energy drinks (HELL, BURN) was investigated on different dental materials: machined, anodized Titanium (grade 5: Ti6Al4V) and composites (Grandio Seal, VOCO; Filtek Z250, 3M ESPE; Estelite SQ, TOKUYAMA). The roughness (Ra) and morphological changes were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). ResultsAFM and SEM revealed significant differences in the Ra and morphology of the samples. AFM results for the machined and anodized titanium samples showed that the two energy drinks modified the surface roughness differently; BURN changed the roughness of machined samples significantly, while anodized discs were not altered significantly by the two energy drinks. In case of composite samples there was no significant difference for the Estelite SQ, relative low differences for the Filtek Z250 and significant changes in the morphology and surface roughness of Grandio Seal. SignificanceOn all tested materials, changes in the surface roughness and morphology were more or less detected, proving energy drinks do in fact have a harmful effect. It can be concluded that material erosion depends on the material composition and particle arrangement. Where the surface is characterized by a regular, uniform particle arrangement, energy drinks are less able to influence the roughness, while for samples where the surface is rich in aggregates, the material erodes the surface much more easily.

In vitro attrition wear resistance of four types of paste-like bulk-fill composite resins

BackgroundRecently, the application of bulk-fill composite resins has increased significantly. Attrition wear and the consequently increased surface roughness of composite resins are among the causes of restoration failure in the posterior teeth. This study aimed to compare the attrition wear and surface roughness of four types of bulk-fill composite resins compared to a conventional composite resin.MethodsEverX-Posterior, X-tra fil, SonicFill 2, and Filtek Bulk-Fill composites (bulk-fill) and Z250 composite (conventional resin composite) were evaluated. Thirty cylindrical specimens (n = 6) were weighed and monitored for 24 h until their weight was stabilized. The primary surface roughness of the specimens was measured by a profilometer. The specimens were then subjected to attrition wear in a chewing simulator. Next, the specimens were weighed, and the surface roughness was measured again. Data were analyzed by one-way ANOVA and Tukey’s post-hoc test at P < 0.05 significance level.ResultsAccording to one-way ANOVA, the difference in weight loss was significant among the groups (P = 0.004) but the difference in surface roughness of the groups was not significant after the attrition wear (P > 0.05). Tukey’s post-hoc test showed that the weight loss of bulk-fill composites was not significantly different from that of Z250 conventional composite after the attrition wear (P > 0.05).ConclusionWithin the limitations of this study, it appears that the tested bulk-fill composite resins are comparable to the conventional composite regarding their attrition wear, increased surface roughness, and weight loss.

Do Self-adhesive Resin Composites Release More Monomers? A Comparative High-performance Liquid Chromatographic Analysis.

To comparatively evaluate the elution of residual monomers (bis-GMA, bis-EMA, TEG-DMA, and HEMA) from two self-adhesive flowable resin composites, a giomer, and a nano-flowable resin composite over five different time intervals, using high-performance liquid chromatography (HPLC). Four flowable resin composites were investigated (Vertise Flow, Constic, Beautifil Flow Plus F03, and Filtek Z350 XT). Immediately after polymerization, each sample was immersed in 75% ethanol/water solution and stored in amber-colored bottles at room temperature. HPLC analysis was performed at predefined time intervals: 1 h, 24 h, 4 days, 8 days and 16 days. The extraction solution was changed after each analysis. Data were analyzed with repeated-measures ANOVA and one-way ANOVA with Tukey's post-hoc test at p < 0.05. The highest mean concentration of residual monomers was eluted from Beautifil, followed by Filtek, and both were significantly higher (p < 0.05) than the mean concentration of eluates from self-adhesive resin composites (Vertise Flow and Constic). Vertise Flow released significantly higher concentrations of HEMA than all the other tested materials. At 1 h post-immersion, 52.2% of monomers were eluted, and continued to elute at a reduced rate throughout the study duration. TEG-DMA was the fastest monomer to leach out, while bis-GMA exhibited significantly higher total mean concentration. The elution rate was significantly dependent on the molecular weight of the eluted monomers. No specific elution behavior can be attributed to self-adhesive RBCs. Elution of residual monomers is dependent on each material's composition, resin matrix characteristics, and the monomer's molecular weight.

Accelerated Aging Effects on Color Change, Translucency Parameter, and Surface Hardness of Resin Composites.

Background The aging process can induce a change in the surface microstructure of materials, the chemical compositions of matrices, and the filler particles of resin composites. This study is aimed at evaluating the effects of accelerated artificial aging (AAA) on the color change, translucency parameter (TP), and surface hardness of resin composites. Methods Five resin composite materials (Tetric N-Ceram, Filtek Z250, Charisma Smart, Herculite Classic, and Escom100) were evaluated. A spectrophotometer was used for color measurements (L∗, a∗, and b∗). TP and color changes (ΔE00) were calculated using the CIEDE2000 formula. The resin materials were subjected to aging for 300 hours. The hardness and TP values were measured before and after AAA. One- and two-way ANOVA and the Tukey test were used. The significance level was accepted as p < 0.05. Results Escom100 had significantly higher ΔE00 values than the other resin composites, and Charisma Smart had significantly lower ΔE00 values than the other tested materials (p < 0.05). Before and after AAA, Charisma Smart had the lowest TP values, and Filtek Z250 exhibited the highest hardness values (p < 0.05). For TP and surface hardness, the effect size value of the composite material was found to be higher than that of AAA. Conclusions After AAA, the investigated resin composites had ΔE00 values that were above clinically acceptable thresholds. After aging, the tested materials generally exhibited decreases in L∗ values and a∗ values, while increases in b∗ values were observed. The ΔTP values of the resin composites were similar. AAA significantly increased the surface hardness of the tested materials.

Comparative Evaluation of Bulk-Fill Composite Resins: Knoop Microhardness, Diametral Tensile Strength and Degree of Conversion.

PurposeBulk-fill composite resins were developed to reduce time and facilitate the restorative procedure. However, considering their recent introduction on the market and the new formulations, their performance still requires evaluation. This study aimed to evaluate Knoop microhardness (KHN), diametral tensile strength (DTS) and degree of conversion (DC) of three Bulk-Fill composite resins and a conventional one.Materials and MethodsSixty samples (n = 15; 8 mm ø x 4 mm height) were confectioned using a mold. Filtek Bulk-Fill (FBF), Tetric N-Ceram Bulk-Fill (TNC) and SonicFill 2 (SF2) were placed in 4 mm increments, and Filtek Z350 (FZ350) was placed in 2 mm increments. The KHN of top and bottom surfaces were tested using Knoop Hardness tester at 10 gf/10s. The DTS was tested under compressive load at 1.0 mm/min. The DC was measured by Fourier Transform Infrared (FTIR) spectroscopy. Differences in DTS and DC were analyzed by ANOVA and Tukey post hoc test. For KHN, Kruskal–Wallis and Wilcoxon tests were performed at α = 0.05.ResultsTop surfaces of all composite resins had higher KHN than bottom surfaces. At top and bottom surfaces, FZ350 showed higher KHN than TNC and SF2. The highest DTS was obtained by FBF, followed by FZ350 and SF2. The highest DC was obtained by SF2, the lowest one was obtained by FBF.ConclusionFrom Bulk-Fill composite resins, FBF presented the best KHN and DTS results. The SF2 showed the best DC. Further studies are required to ensure whether these differences can negatively influence the behavior of in vivo restorations.

Evaluation of Shear Bond Strength of Resin-Based Composites to Biodentine with Three Types of Seventh-Generation Bonding Agents: An In Vitro Study.

Methods Forty-eight acrylic blocks having central holes with a nominal diameter of 4 mm and a depth of 2 mm were prepared. The holes of the acrylic blocks were filled with Biodentine, which was prepared following the guidelines provided by the manufacturer. Then, the specimens were divided into six groups (n = 8). Groups 1, 2, and 3, Tetric N-Ceram composite bonded to Biodentine with Tetric N-bond, Xeno V+, Bond Force bond, respectively. Group 4, 5, and 6, Filtek Z350 bonded to Biodentine with the same three adhesives. The specimens were placed in distilled water for 24 hours and tested for the SBS in a universal testing machine at a crosshead speed of 1 mm/min. The test data were listed in a table and independent samples t-test and analysis of variance (ANOVA) were conducted as a part of the statistical analysis. Results The Tetric N bonding agent achieved the highest SBS followed by Bond Force, and Xeno V and highly significant difference was found. On the other hand, an overall increase in the SBS values of the Tetric N-Ceram resin was noticed in comparison with the Filtek Z350 and the differences was statistically significant. Although the specimens failed in adhesive, cohesive and mixed fracture modes but the cohesive was found to be the dominant failure mode in all groups. Conclusion Among the tested bonding agents and resin composites, the Tetric N-Ceram composite bonded by Tetric N-bond self-etch adhesive with the Biodentine showed the highest SBS compared to the other combinations.

Effect of Additional Dry Heat Curing on Microflexural Strength in Three Types of Resin Composite: An In Vitro Study

Aim: Additional dry heat curing is a method that favorably influences the mechanical properties of an indirect resin composite restoration. Microflexural strength is a property currently applied for the evaluation of indirect resin composite restorations. The aim of the present study was to assess the effect of additional dry heat curing on microflexural strength in three types of direct-use resin composites. Materials and Methods: This in vitro study consisted of 70 resin composites samples made with a 6 × 2 × 1 mm metal matrix and divided into seven experimental groups, which included Gr1a: Tetric N-Ceram without additional dry heat curing (n = 10); Gr1b: Tetric N-Ceram with additional dry heat curing (n = 10); Gr 2a: Filtek Z350 XT without additional dry heat curing (n = 10); Gr2b: Filtek Z350 XT with additional dry heat curing (n = 10); Gr3a: Filtek Z250 without additional dry heat curing (n = 10); Gr3b: Filtek Z250 with additional dry heat curing (n = 10); and Gr4: SR Nexco Paste (control) without additional dry heat curing (n = 10). The samples were stored in distilled water at 37 °C for 24 h. A universal testing machine with a 2000 N load cell at a speed of 1 mm/min was used to assess flexural strength. The data were analyzed with a parametric ANOVA test with Tukey’s post hoc intergroup factor (for groups without heat treatment) and a nonparametric Kruskall Wallis test with Bonferroni’s post hoc (for groups with heat treatment). In addition, the comparison of independent groups in each resin composite type with and without heat treatment was performed with a Mann Whitney U test. A significance level of p &lt; 0.05 was considered. Results: The Filtek Z250 resin composite with and without additional dry heat curing presented the highest microflexural strength values with 137.27 ± 24.43 MPa and 121.32 ± 9.74 MPa, respectively, while the SR Nexco Paste (control) resin composite presented the lowest microflexural strength values with 86.06 ± 14.34 MPa compared to all the resin composites with additional dry heat curing. The Filtek Z250 and Filtek Z350XT resin composites with and without additional dry heat curing presented significantly higher microflexural strength versus the SR Nexco (p &lt; 0.05) and Tetric N-Ceram (p &lt; 0.05) resin composites. In addition, the Filtek Z350XT and Tetric N-Ceram resin composites with additional dry heat curing showed significantly higher microflexural strength (p &lt; 0.05) compared to those without additional dry heat curing. Conclusions: The Filtek Z250 and Z350XT resin composites had significantly higher microflexural strength values with and without additional dry heat curing. In addition, the Filtek Z350XT and Tetric N-Ceram resin composites subjected to additional dry heat curing showed significantly higher microflexural strength compared to when they did not receive the same procedure, a situation that did not occur with the Filtek Z250 resin composite.