Surface Roughness Of Composites Research Articles

Tuning high- and low-temperature rheological properties of warm-mixing asphalt composites by functionalized waxes

Traditional asphalt road construction utilizes hot-mixing asphalt mixtures. High temperatures not only accelerate the aging of asphalt, but also produce large amounts of toxic and greenhouse gases. To alleviate these problems, wax-based warm-mixing agents are applied, and asphalt pavement construction temperatures can be efficiently lowered, resulting in lower energy and gas emissions. To systematically evaluate the effects of composition and structure of warm-mixing agents on rheological properties of asphalt at high and low temperatures, a series of functionalized waxes (i.e., oxygen-containing groups, amide groups, and long-chain aliphatic hydrocarbons) were designed in this work, followed by a melt-mixing process with asphalt. The findings demonstrated that warm-mixing agents with long-chain aliphatic hydrocarbons could significantly improve asphalt composites’ rheological properties at high temperatures, such as good viscosity-reducing effect and superior rutting resistance or permanent deformation resistance; warm-mixing agents with oxygen groups were able to improve the asphalt composites’ resistance to low-temperature cracking; amide group-containing warm-mixing agents could improve the surface roughness of asphalt composites. This work provides a practical guide for the selection of functionalized warm-mixing agents for asphalt pavement under multiple environmental factors.

Effect of Various Toothpaste Tablets on Gloss and Surface Roughness of Resin-based Composite Materials.

To evaluate the effect of various toothpaste tablets on gloss and surface roughness of resin-based composite. Sixty-four resin-based composite specimens were divided into four groups of 16 specimens each. Gloss and roughness were measured before and after simulated brushing with three types of toothpaste tablets and one conventional toothpaste: CT: Chewtab Toothpaste Tablets; AT: Anticavity Toothpaste Tablets; HC: Charcoal Toothpaste Tablets; CP: Cavity Protection toothpaste. The Kruskal-- Wallis procedure was performed to compare the differences by groups. Post-hoc comparisons were conducted with Bonferroni corrections (α=0.05). There was a significant drop in gloss for all groups. CT and AT maintained the highest gloss with means of 81.6 GU and 74.1 GU, respectively. The lowest gloss of 24.5 GU was observed for HC. There was a significant increase in roughness for all groups except for CT. CT had the lowest roughness with a mean of 0.034 μm, while HC had the highest roughness with a mean of 0.074 μm. There was a significant correlation between post-brushing gloss and post-brushing roughness (p<0.001, r=-0.884). Chewtab Toothpaste Tablets had the least effect on gloss and roughness, while Charcoal Toothpaste Tablets had the most negative effect on the surface properties of resin-based composites.

The effect of different liquids on the surface roughness and color stability of single shade and nanohybrid resin composites: An AFM and SEM analysis.

The aim of this study is to evaluate the surface roughness (SR) and color changes of single-shade and nanohybrid resin-based restorative materials (RBC) after immersion in liquids at different pH values. For RBCs, a total of 120 specimens, 30 for each material, were prepared using 10 mm diameter and 2 mm thick molds. For flowable bulk fill RBC, a total of 40 specimens, 10 for each material, were prepared using 10 mm diameter and 4 mm thick molds (n = 10). After initial color and SR measurements, samples were stored in the liquids for 14 days and all of the measurements were repeated on 14th days. Scanning electron microscopy and atomic force microscopy analyzes were performed in all groups. When SR results are examined; among all liquids, the highest SR value was observed in the Carisma Diamond One (CDO) group, while the lowest SR value was observed in the Omnichroma Flow Bulk (OMF) group (p < .05). When the color changes (ΔE) results are examined; it was observed that CDO group had highest color change and OMF group had the lowest values. It has been observed that among the liquids, the liquids that affect the ΔE values of the materials the most are coffee and cola. When the ΔE values of the subgroups of the materials were examined, there was a statistically significant difference in all subgroups of RBCs (p < .05). While acidic liquids increased the SR of RBCs, coffee more affected the color change of RBCs. RESEARCH HIGHLIGHTS: Clinicians should keep in mind that the RBCs tested may change their surface properties and colors when exposed to various liquids. People who have RBCs should pay attention to the consumption of acidic and highly pigmented liquids.

Color and surface roughness alterations of bulk-fill resin composites submitted to simulated toothbrushing with whitening dentifrices

Aim: To evaluate the surface roughness and color stability of bulk-fill resin composites after simulated toothbrushing with whitening dentifrices. The radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA) of dentifrices were also assessed. Methods: Specimens (n=10) of Tetric N Ceram Bulk Fill (TNCB), Filtek One Bulk Fill (FOB) resin composites, and Z100(Control) were prepared using a cylindrical Teflon matrix. Surface roughness (Ra, μm) was assessed by a roughness meter and the color evaluations (ΔEab , ΔE00 , WID ) were performed using a digital spectrophotometer based on the CIELAB system. Three measurements were performed per sample, before and after simulated toothbrushing with 3D Oral-B White Perfection (3DW) and Black is White (BW) dentifrices. The abrasivity (REA and RDA values) of the used dentifrices was also determined by the Hefferren abrasivity test. Results: The Ra values increased significantly in all resin composites after 3DW and BW toothbrushing. The acceptable threshold color varied among resin composites, and TNCB and Z100 presented the highest ΔEab and ΔE00 for BW dentifrice. The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Conclusions: simulated toothbrushing with tested whitening dentifrices increased the surface roughness at acceptable levels. The Tetric N Ceram Bulk-fill and Z100 composite showed the highest color alteration in BW. 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White.

Effect of an Effervescent Multivitamin on Color and Surface Roughness of Micro-Hybrid Dental Resin Composites.

The use of multivitamins has become widespread globally, yet there is a scarcity of studies investigating their impact on resin composite restorations. This study aimed to evaluate the effect of an effervescent multivitamin tablet on micro-hybrid dental resin composites' surface roughness and color. Fifty disc-shaped samples (8 × 2 mm, shade A2; n = 10) were prepared and polished using five different micro-hybrid resin composites (Pergamon, Dentac, Turkey; Estelite Posterior, Tokuyama, Japan; Geanial Anterior, GC, Japan; Charisma Opal, Kulzer, Germany; Beautifil II, Shofu, USA). Samples were immersed in 200 mL water to one effervescent multivitamin tablet (Redoxon Triple Action, Bayer) at 24 °C for 2 min a day in 24 h intervals for 30 days. All samples' surface roughness (Ra) and ΔE(L*a*b) measurements were recorded at the beginning and end of the 30 days. The Wald chi-square and a two-way ANOVA were used for statistical analysis (significance level p < 0.05). The resin composite type and exposure to the multivitamin had a statistically significant effect on Ra values (p < 0.05). The resin composite type had a statistically significant effect on ΔE values, likely due to the higher mean value of BII (p = 0.040). The surface roughness and color of resin composites can be affected by multivitamins with a pH value of 3.0. Therefore, it is important to consider the patient's routine vitamin intake during resin composite selection. Additional research is required to explore the properties of different dental restorative materials.

The Effects of Home and Over-The-Counter Whitening Agents on Surface Roughness and Microhardness of High Aesthetic Composites

Objectives: The aim of this in-vitro study is to compare the effect of the newly released peroxide-free over-the-counter whitening products and the home bleaching material containing carbamide peroxide, on high aesthetic composites. Materials and methods: In our study, 4 different composites were used: supra-nano(Tokuyama Estelite Asteria), submicron hybrid(Brilliant Ever Glow), nanofil(Filtek Universal Restorative) and finally nano-ceramic(Ceram.x SphereTEC one). A total of 200 disc-shaped composite specimens with 2 mm thickness and 8 mm diameter were prepared using metal molds(n=10). One surface of the samples was polished using Sof-Lex™ XT discs. Composite groups were divided into 5 subgroups as 4 experimental and 1 control groups. Four bleaching products, namely Opalascence Home Type, Mr. Blanc, I-White, Cali White, were used in the experimental groups. It was kept in a drying oven at 37°C to imitate the temperature of the mouth on certain days and hours in accordance with the instructions written in the whitening products prospectus. The surface roughness of the samples was measured with a profilometer and the microhardness values were measured with a fully automatic Micro Hardness Tester. The surfaces were examined with a Scanning Electron Microscopy. Data were evaluated with two-way Variance Analysis and Tukey Test as statistical methods. Results: According to the surface roughness data, Filtek Universal Restorative's I-White subgroup showed the highest average surface roughness value, and Tokuyama Estelite Asteria's I-White subgroup showed the lowest value. There was a meaningful difference between the composite main groups and the experimental subgroups(p&amp;lt;0.05). According to microhardness data, I-White subgroup of Tokuyama Estelite Asteria showed the highest average microhardness value and the lowest value was Brilliant Ever Glow's I-White subgroup. A meaningful difference was observed between the composite main groups and the experimental subgroups(p&amp;lt;0.05). Although OTC bleaching products did not significantly change the surface roughness and microhardness values of composite resins, when SEM analyzes were examined, it was observed that all OTC bleaching products caused more cleft, crack and defect-like changes on the composite surfaces compared to Opalescence home bleaching agent. Conclusions: It can be stated that Filtek Universal Restorative material is the composite that is most negatively affected by whitening materials, while Tokuyama Estelite Asteria composite is the least affected.

Effect of Different Polishing Systems on the Surface Roughness and Gloss of Novel Nanohybrid Resin Composites

Effect of Different Polishing Systems on the Surface Roughness and Gloss of Novel Nanohybrid Resin Composites

The Effect of Modeling Liquid on Color Stability and Surface Roughness of Single-Shade Composites: A SEM Study

The aim of this study; to evaluate the effects of modeling liquid use on the surface roughness and color change of single-shade universal composite resins. Total 174-cylinder shaped samples (60 roughness, 54 FE-SEM analysis, 60 color measurements) were prepared in 6 groups, (n=10) 3 of only composites, 3 of composites and modeling liquid. Composite samples were stored in coffee for 7 days and then bleached with 35% Total Blanc Office. FE-SEM analysis, color changes and roughness were measured. For statistical analysis, Two-way Anova test were used (p&lt;0,05). There is a statistically significant difference between the groups with and without modeling liquid in terms of roughness and color changes (p&lt;0,05). The highest roughness and color changes findings were observed in Essentia groups for all measurement times. When Essentia modeling is applied with liquid, the decrease in roughness and color changes is insignificant at the baseline, but the decrease is statistically significant after staining and after bleaching. FE-SEM findings show surface changes in single-shade composites after staining and bleaching. The use of modeling liquids affects the surface roughness of single-shade composites. It is also seen that the modeling liquid used on the surface of the composites protects the surface.

Assessment of surface roughness and compressive strength of resin-based composite using different types of bleaching protocols.

Background and objective: This study aimed to evaluate the effect of three types of bleaching protocols on the surface roughness and compressive strength of composite resin. Methods: Eighty composite resin samples were prepared using metal molds; forty samples (2 mm in height and 8 mm in diameter) for surface roughness evaluation and the other forty samples (6 mm in height and 4 mm in diameter) for compressive strength. Every forty samples were divided into four groups; Group 1 (n = 10) The samples were stored in deionized water at 37°C for two weeks as control, group 2 (n =10) The samples were subjected to bleaching with 22% Carbamide Peroxide (CP) Home bleaching, group 3 (n =10) The samples were subjected to bleaching with 14% Hydrogen Peroxide (HP) Home bleaching and group 4 (n =10) The samples were subjected to bleaching with 25% Hydrogen Peroxide (HP in-Office) in a dental clinic. After bleaching, groups 2, 3, and 4 were evaluated for surface roughness and compressive strength. Results: The enamel surface roughness of all specimens were increased after bleaching protocols to a very similar extent with no statistically significant difference between the means of enamel roughness of the control group and the other three groups and the highest value was recorded in the Carbamide Peroxide group (CP), while compressive strength of the composite was decreased after using bleaching protocols in all groups in comparison with the control group and the least compressive strength was recorded in (HP) group followed by (HP in-Office) group and (CP) group respectively. Conclusions: Within the limitation of this study, the following conclusions can be drawn: There was a decrease in surface roughness using different types of bleaching protocols (22% CP and 14% HP) at-Home bleaching technique and (25%) in-Office HP bleaching. Although there was no significant difference between them. The compressive strength of the composite resin was reduced after bleaching with no significant difference. Keywords: Bleaching protocol, Hydrogen peroxide, Carbamide peroxide

In vitro comparison of one-step, two-step, and three-step polishing systems on the surface roughness and gloss of different resin composites.

This laboratory study evaluated the effect of three polishing systems on the surface roughness and gloss of resin composites. Thirty specimens (6 mm Ø × 8 mm) were fabricated from each of three resin composites: Z 350 XT (nanofill), Harmonize (nanohybrid), and Estelite Omega (supranonofill). All specimens were photopolymerized using a multi-peak LED curing unit (VALO-Standard mode), having a exitance irradiance of approximately 1000 mW/cm2 against a polyester strip (PS). 2 mm was then removed from the irradiated end (finished) using #320 abrasive paper (F). Specimens were then randomly polished (P) using a one-step (1S) (OneGloss), two-step (2S) (EVE Diacomp Twist Basic CA), or 3-step (3S) (Astropol P) system (n = 10). For PS, F, and P groups, surface roughness (Ra) was measured using a surface roughness tester, and surface gloss was measured with a glossmeter. For each specimen, the percent recovery to the PS value (%R) of surface roughness and surface gloss were calculated. Data were analyzed using two-way ANOVA, followed by Tukey's test. Surface roughness and gloss values were submitted to Pearson's correlation test (α = 0.05). All statistical testing was performed using a pre-set alpha of 0.05. The interaction term [resin composite × polishing system] was significant for both surface roughness (p = 0.001) and gloss (p = 0.0001). For all resin composites, the 2S and 3S systems provided a higher %R of surface roughness and gloss compared to those of the 1S system. There was a negative correlation between surface roughness and gloss, but only a few combinations showed strong correlations. The 2S and 3S polishing systems provided surfaces having greater smoothness and gloss compared to the 1S system. The ability to recover surface roughness and gloss was dependent on type of resin composite filler classification. The 3S and 2S polishing systems were more effective in achieving PS values than was the 1S system for all tested resin composites. However, individual polishing systems performed differently depending on type of resin composite.

Effect of processing conditions and electrode materials on the surface roughness of EDM-processed hybrid metal matrix composites

The current investigation aims to investigate the role of four major input parameters, i.e. Current (I), Gap Voltage (V), Pulse off time (Toff), and Pulse duration (Ton) on surface roughness (Ra) of Al–Mg-0.6Si-0.275Cu/SiC10 % hybrid composite samples fabricated by Stir-casting. In addition, paper focuses on the goal to ascertain the impact of distinct tool materials on surface morphology of Al/SiC composite. Further, mathematical models were developed using the L29 orthogonal array in the Stat-Ease Modelling Expert V7.0 software. Thus, to validate the significance of the developed models, an Analysis of Variance was used. Finally, the topography of the specimen's surface (pre and post-machining) was performed using scanning electron microscopy (SEM). The results showed that at a peak current of 5 Amp, Gap voltage of 100V, Pulse on time of 100 μs, and Pulse off time of 40 μs, the lowest surface roughness with brass and copper electrodes was 0.29 μm and 0.32 μm obtained. The Brass electrode yielded 9.3 % lower surface roughness than the copper electrode.

Wire Electric Discharge Machining of Aluminium Hybrid Composite: Renewable Energy Based IoT Approach

Wire Electric Discharge Machining (WEDM) has been recognized as one of the optimum methods for machining of harder aluminum-based hybrid metal matrix composites (AHMMC). This method is used to optimize the major control aspects of a machine and they are current, pulse duration, and rate of feed of wire on kerf width (KRW) and Surface roughness (Ra) of hybrid composites made of aluminum Al6351 as the metal matrix (AMMHC). The AMMHC has been created via a stir casting technique by adding SiC and B4C with an Al6351 matrix. Box-Behnken design (BBD) has been used to conduct tests in order to parametrically optimize the WEDM process. The optimization of KRW and Ra is identified using 3-D surface plots, graphs and response table of ANOVA as well as by employing Response Surface Methodology (RSM). Internet of Things (IoT) is implemented to monitor the quality of electrolyte that is used in WEDM. It has been identified that the current has a major contribution in both KRW and Ra factors. A lower current is preferred for a lower KRW whereas higher current improves Ra value.

Surface Roughness Evaluation of Resin Composites after Finishing and Polishing Using 3D-Profilometry

The purpose of this study was to evaluate the effect of two finishing and polishing methods on the surface roughness of different resin composites. Twenty-two disk-shaped specimens of five resin composites Zirconfill® (ZF), Filtek™ Supreme XTE (FS), Brilliant EverGlow™ (BG), Ceram.X® Duo (CD), and Harmonize™ (HA) were prepared for each one using a silicon mold. Both surfaces of each specimen were first grinded with 600-grit silicon carbide paper in a moistened environment. The polishing methods used included the two-step Enhance® and PoGo® polishing system (E/P) or the four-step SwissFlex® discs (SFD). Surface roughness was evaluated using a noncontact 3D-optical profilometer. Surface morphology was examined by scanning electron microscopy. Data were analyzed using two-way analysis of variance and pairwise comparisons with Tukey’s test ( α = 0.050 ). Surface roughness was affected by both the type of resin composite ( p &lt; 0.001 ) and the finishing and polishing system ( p &lt; 0.001 ), with a significant interaction between these two factors ( p = 0.025 ). The E/P system produced smoother surfaces than the SFD system ( p &lt; 0.001 ). For the E/P system, the highest mean roughness value was obtained with ZF and was statistically different from all other composites, whereas inhomogeneous results among resin composites could be found for the SFD system. Surface roughness was material-dependent, and the polishability of the resin composites was best accomplished using the E/P system. Within each F/P system studied, BG showed the lowest average surface roughness and ZF registered the highest.

PEEK surface treatment on surface roughness and bond integrity to composite resin utilizing Er: YAG, Rosebengal activated by PDT, and aluminum trioxide particles

AimsTo evaluate the impact of conditioning protocols, aluminum trioxide (Al2O3), Er:YAG laser (EYL), and Rosebengal (RB), on the surface roughness (Ra) and shear bond strength (SBS) of polyetheretherketone (PEEK) attached to composite restorations. MethodEighty PEEK discs in total were produced and then divided into four groups (n = 20). Group1:Sulfuric acid (SA), Group 2: PDT (RB), Group 3: Al2O3, Group 4 EYL, respectively. The Ra of PEEK discs was evaluated using the surface profilometer. After being luted, the discs were attached to composite resin discs. After that, samples were put to SBS testing on a Universal testing apparatus. A stereo microscope was also used to evaluate the type of breakdown. The data were analyzed using Tukey's test and one-way analysis of variance. ResultsThe SA treated group exhibited the highest Ra. Nevertheless, the RB specimens activated by PDT treatment had the lowest mean Ra score. The group that received the treatment of SA exhibited the highest average score of SBS. In contrast, specimens treated with PDT and activated by RB exhibited the lowest levels of bond fidelity. Cohesive failure emerges as the prevailing kind of fracture within the various groups subjected to testing. ConclusionThe utilization of Al2O3, RB activated by PDT, and EYL shows promise as a viable substitute for Sulfuric acid in enhancing the bond integrity of composite cement and surface roughness in PEEK materials

Correlation between Infill Percentages, Layer Width, and Mechanical Properties in Fused Deposition Modelling of Poly-Lactic Acid 3D Printing

The field of additive manufacturing (AM) has seen a transformation in the production of intricate and complex parts for various applications. Fused Deposition Modelling (FDM), among AM techniques, has garnered significant attention, particularly in fields like fibre-reinforced composites (FRC). In this study, the world of FDM-printed Polylactic Acid (PLA) components is explored, with a focus on how mechanical properties are influenced by infill percentages and layer widths. Through the utilisation of Response Surface Methodology (RSM), the optimisation of FDM-PLA 3D printing for a wide range of biomaterial applications is achieved, along with the unveiling of the potential for remarkable improvements in mechanical performance. Notably, a remarkable 91% reduction in surface roughness for PLA composites was achieved, accompanied by an impressive 25.6% and 34.1% enhancement in the tensile strength and Young’s modulus of fibre-reinforced PLA composites, respectively. This work, positioned at the crossroads of FDM, lays the groundwork for substantial advancements in the realm of additive manufacturing.

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.

Effect of Brushing with Whitening Toothpaste on Color Stability and Surface Roughness of Color-Adjustment Resin-Based Composites

Objectives: Aim of this study is to compare the color stability and surface roughness of four different color-adjustment composites produced using smart chromatic technology and a highly esthetic nano-hybrid composite after brushing with whitening toothpaste. Materials and Methods: 4 different color adjustment composites and 1 nano hybrid composite are divided into 5 main groups according to their contents. A total of 120 disc-shaped specimens (8 x 2 mm) were prepared, 24 in each group. The prepared samples were sequentially kept in solutions (tea, coffee and cherry juice) for 12 days and randomly divided into 3 subgroups (n=8). Subgroup 1, brushing with distilled water; Subgroup 2, brushing with whitening toothpaste; Subgroup 3, home bleaching agent were applied (14 days). Color measurements were made with a spectrophotometer, ΔE values were calculated using the CIELAB formula. Surface roughness values were made using a profilometer device. Samples from each group were selected for SEM surface analysis. Results: Among the composite groups, the highest coloration was observed in the Omnichroma, while the lowest ΔE values were observed in the Vittra composite group. Although the ΔE values on the 14th day were higher than the 7th day in all groups, the differences between them were statistically insignificant(p&amp;gt;0.05) In all composite groups (except Omnichroma), the ΔE values of brushing with whitening toothpaste at the end of the 14th day were higher than brushing with distilled water(p&amp;lt;0.05). Conclusions: Although the application of home bleaching agent was found to be more effective in a short time in whitening color-adjustment composites; brushing with whitening toothpaste at the end of the 14th day was found to be as effective as the application of home bleaching agent. Coloring and bleaching procedures applied to color-adjustment restorative materials did not have a significant negative effect on surface roughness values.

Influence of surface roughness of universal shade resin composites on color adjustment potential.

This study aimed to determine the influence of surface roughness of the color adjustment potential restoration of universal resin composites. A structural colored resin composite (Omnichroma, OC) and a pigment-employed universal shade resin composite (Beautifil Unishade, BU) were used. Each resin composite was placed in a cavity to determine its ability to match the color of artificial teeth. The surface of the resin composites was polished with #800- or #2000-grit SiC paper before performing color measurements. One-way analysis of variance and Tukey post hoc tests were performed (α=0.05). The color difference (ΔE*ab) ranged from 2.5-3.9 for OC and 1.8-8.7 for BU. OC has a more stable color adjustment than BU. The color adjustment potential of universal resin composites was affected by the surface roughness of the restorations.

Influence of oligomeric resins on natural rubber-carbon black-silica composites for tire tread application

The investigation aims to understand the impact of different resins on properties of natural rubber (NR) based tire tread composites, providing valuable insights for the optimization of tire performance. In current research six different types of resins, namely rosin modified dicyclopentadiene(DCPD), gum rosin, C5 aliphatic resin, alpha methyl styrene (AMS) resin, koresin and terpene phenol resin, were selected for assessing structural influence of resins on cure characteristics, reinforcement, abrasion resistance, cut-tear resistance, heat-build-up, viscoelastic properties of carbon black-silica loaded NR composites. During mixing of rubber composites, condensation reaction between hydroxyl groups of silica with phenolic groups of koresin and terpene phenol resin, leading to elimination of water molecules was confirmed by Fourier transform infrared spectroscopy. The addition of resins led to a reduction in crosslink density, maximum torque and delta torque. The compounds with gum rosin and rosin modified DCPD showed lower crosslink densities translating into lower tensile strength, lower stress at 100%, 200%, 300% strain, and higher elongation at break among the resins. Rosin modified DCPD based composite exhibited the highest cut growth resistance and tear strength. Rolling resistance indicator (tanδ@70 °C) of resin-based composites followed the order: gum rosin > rosin modified DCPD > koresin > C5 resin > terpene phenol resin > AMS resin. The snow traction (tanδ@-15 °C), the order was: AMS = C5 > gum rosin > terpene phenol = koresin > rosin modified DCPD. The dynamic stiffness (É) of the gum rosin-based compound was significantly increased at low strain (0.1%) and low temperatures (-80–20 °C) compared to other resins. Furthermore, atomic force microscopy was employed to analyze surface topography and roughness of the resin-based NR composites, providing valuable insights into interfacial characteristics.

Effect of whitening concepts on surface roughness and optical characteristics of resin-based composites: An AFM study.

The aim of this study was to evaluate the effects of various whitening agents on the surface roughness and optical characteristics of different types of resin composite restorations. Fifty specimens were prepared for each resin [G-aenial Posterior (GP), SonicFill-2 (SF), Solidex (SDX), and Nova Compo HF (NC)]. Following baseline color and surface roughness (Ra) measurements, the specimens were randomly divided into 5 groups (n = 10/group) according to whitening concepts: control (distilled water), in-office bleaching [OB-(Opalescence Boost)], at-home bleaching [HB-(Opalescence PF)], whitening toothpaste [WT-(Signal White Now)], and whitening mouthwash [WM-(Listerine Advanced White)]. ∆E00 , ∆TP00 , and ∆WID values were calculated before and after the whitening procedure with a spectrophotometer using the CIEDE2000 formula. Surface roughness measurements were repeated. The surface topography was determined using atomic force microscopy. Two- and three-way analyses of variance and Tukey's post-hoc test were performed, with p < 0.05 regarded as indicative of significance. No significant differences were detected among the resin composite materials in terms of the ΔE00 values (p > 0.05). Color change of all resin materials was above the AT threshold (>1.8) and the PT threshold (>0.8). All restorative materials presented acceptable (AT<2.62) TP00 values. Solidex specimens demonstrated the lowest WID values compared to the other composites. There were significant differences among the whitening procedures with respect to ΔE00 , ΔTP00 , and WID values (p < 0.001). SF/WT combination showed the highest and clinically unacceptable ΔE00 values. The highest roughness values were observed in the SDX specimens and the combination of SDX/OB. The effect of whitening agents on the optical characteristics and surface roughness of restorative materials depends on the type of material, agent, and time. RESEARCH HIGHLIGHTS: Clinicians should be aware that long-term use of over-the-counter products due to the abrasive effects of their ingredients and repeated bleaching session applications may affect the color stability and surface roughness of resin composites.