Hybrid Composite Resin Research Articles

The influence of red mud filler on flexural strength in vinyl ester resin Hybrid composites with abaca fiber (Musa Textilies)

The influence of red mud filler on flexural strength in vinyl ester resin Hybrid composites with abaca fiber (Musa Textilies)

Nanoindentation creep: The impact of water and artificial saliva storage on milled and 3D-printed resin composites.

This study evaluated the effects of artificial saliva and distilled water on the nanoindentation creep of different 3D-printed and milled CAD-CAM resin composites. Disk-shaped specimens were subtractively fabricated from polymer-infiltrated ceramic network (EN) and reinforced resin composite (B) and additively from resin composite (C) and hybrid resin composite (VS) using digital light processing (DLP). Specimens from each material were divided into two groups according to their storage conditions (artificial saliva or distilled water for 3 months). Creep was analyzed by nanoindentation testing. Statistical analysis was done using two-way ANOVA, one-way ANOVA, Bonferroni post hoc tests, and independent t-test (α = 0.05). The main effects of material and storage conditions, and their interaction were statistically significant on nanoindentation (p<0.001). Storage condition had the greatest influence (partial eta squared ηP 2 =0.370), followed by the material (ηP 2 = 0.359), and the interaction (ηP 2 = 0.329). The nanoindentation creep depths after artificial saliva storage ranged from 0.34 to 0.51µm and from 0.50 to 0.87µm after distilled water storage. One of the additively manufactured groups had higher nanoindentation creep depths in both storage conditions. All specimens showed comparable performance after artificial saliva storage, but increased nanoindentation creep after distilled water storage for 3 months. The subtractive CAD-CAM blocks showed superior dimensional stability in terms of nanoindentation creep depths in both storage conditions. Additively manufactured composite resins had lower dimensional stability than one of the subtractively manufactured composites, which was demonstrated as having higher creep deformation and maximum recovery. However, after artificial saliva storage, one of the additively manufactured resins had dimensional stability similar to that of subtractively manufactured.

Effect of the Application Procedure on The Bond Strength of Universal Adhesive in Restoration Repair

Objective: This study aimed to evaluate the effect of reduced application time on the bond strength of a universal adhesive used for the repair of hybrid ceramic and composite resin restorations. Methods: In the study, a total of 48 rectangular prisms of sizes 7×6×2 mm hybrid ceramic (Vita Enamic, Zahnfabrik, Germany) and composite resin (Solare X, GC, Japan) specimens were prepared. All samples were aged with 5000 thermal cycles. Then, the upper surfaces of the samples were roughened with a diamond fissure bur (10–36µ, 852 FG Meisinger; Hager &amp;amp; Meisinger GmbH, Germany) with 5 strokes under water cooling. The samples were divided into 2 subgroups according to the different application times of the adhesive system (G-Premio Bond, GC, Japan) (n=12). Then, composite resin (Solare X, GC) was placed using plastic cylinder molds with 3 mm inner diameter and height and cured with light for 20 seconds. All samples were thermal aged and then a shear bond strength test was conducted. The data were analyzed with Two-way ANOVA and post-hoc Tukey HSD tests (p˂0,05). Results: Two-way ANOVA revealed that the repair bond strength of the 10 seconds of waiting was significantly higher than the quick application for both hybrid ceramic and composite resin (p˂0,05). It was determined that there was no significant difference between hybrid ceramic and composite resin in the both quick application group and 10 seconds waiting group (p˃0,05). Conclusion: Quick application procedure showed lower shear bond strength than 10 seconds waiting group for the repair of both composite resin and hybrid ceramic (p&amp;lt;0,05). Keywords: Quick application, Application time, Universal adhesive, restoration repair..

Investigation on mechanical and acoustic properties of natural fiber‐based sustainable green resin hybrid composites

AbstractThe use of natural fibers has been suggested by researchers for the purpose of promoting environmental sustainability. In this work, hybrid composites made of coir and banana fibers were fabricated by using both green resin and epoxy resin in the preparation of composites. Soybean oil is used in this work as the eco‐friendly resin. To determine the mechanical characteristics of the composites, a number of experiments were carried out including tensile, compression, hardness and impact tests. In addition, testing was done on the sound absorption qualities. Composites composed of green resins exhibit superior environmentally friendly characteristics and mechanical robustness in comparison to composites based on epoxy resin. The tensile strength of the hybrid composites exhibited superior performance compared to other hybrid composites. The additional mechanical qualities of the hybrid composites are noteworthy and serve as a driving force to pursue the development of specific applications.Highlights Hybrid composites exhibit superior mechanical properties. The use of natural resin‐based composites is limited. There is a potential scope for developing hybrid composites using natural fibers and resin for acoustic applications.

A Comparative Evaluation of the Shear Bond Strength of Three Different Hybrid Tooth-Colored Restorative Materials to Dentin: An In-Vitro Study.

Silver amalgam, glass ionomer, resin-modified glass ionomer, compomers, light polymerized hybrid composite resin, and hybrid glass ionomer are among the most frequent restorative materials used as cavity-based or post-endodontics. Thus, to meet the needs of both patients and dentists, Cention N reimagines the traditional filling by integrating bulk placement, ion release, and durability into a dual-curing, aesthetically pleasing solution. Hoewver, we do not have enough information from studies comparing this hybrid restorative material's shear bond strengths to dentin to draw any firm conclusions. Cention N, zirconomer, and Vitremer are three hybrid tooth-colored restorative materials that were evaluated for their shear bond strength to dentin. This research aimed to compare and evaluate these materials. The purpose of this research was to use a universal Instron machine to measure the shear bond stress of three distinct hybrid tooth-colored restorative materials in relation to dentin.The research samples consisted of 45 extracted lower first premolars from humans.The teeth were then assigned into three groups of 15 samples each according to different color acrylic resin blocks, namely, group A (pink acrylic blocks), which had Cention in cement; group B (white acrylic blocks), which has zirconomer cement; and group C (violet acrylic blocks), which had Vitremer cement. There was no statistically significant difference between the three groups and the normal distribution, as shown by the negligible values in the tests involving the three groups. Put simply, each of the three categories exhibits data that follows a normal distribution. This allows for further data analysis to be conducted using the parametric test of significance. The shear bond strength of hybrid glass ionomer restorative materials has to be further investigated in both laboratory and living organism settings.

Clinical Performance and Wear Resistance of Highly Translucent Nano Zirconia Reinforced Glass Ionomer Filling Versus Conventional Resin Composite Restorations in Patients with Proximal Carious Teeth: Randomized Clinical Trial

Aim: This study aimed to evaluate the clinical performance and occlusal wear resistance of nano- zirconia reinforced glass ionomer restorations in comparison to nano-hybrid resin composite restorations in proximal cavities. Material and Method: This randomized clinical trial was conducted on thirty-two patients who had proximal carious lesions in posterior teeth. Participants were randomly allocated into two groups (n=16 for each group) in which they received either; Nano zirconia reinforced glass ionomer restorations (Zirconomer Improved, Shofu, Japan) or Conventional nano hybrid resin composite (Filtek Z250 XT, 3M ESPE, USA), all materials were applied according to manufacturers’ instructions. Restorations were evaluated at baseline (immediately), after six months, and after 12 months by two blinded assessors using modified USPHS criteria measuring (postoperative hypersensitivity, secondary caries, gross fracture, color match, cavo-surface marginal discoloration, marginal integrity, proximal contact and wear resistance). Data was analyzed using Medcalc software, intergroup comparisons between interventions was performed using the Chi-Squared test with statistical significance level set at (P ≤ 0.05) while intragroup at (P ≤ 0.016) after Bonferroni correction, relative risk was used to assess the clinical significance. Results: Intergroup comparison between both materials regarding USPHS criteria and wear resistance have shown no statistically significant difference within different follow up periods; baseline, 6 and 12 months respectively except for the color match shown significant difference with highly translucent nano zirconia reinforced GI. Intragroup comparison within highly translucent nano zirconia reinforced glass ionomer and within conventional resin composite regarding USPHS criteria have shown no statistically significant difference between different followup periods except for the wear resistance shown significant difference within highly translucent nano zirconia reinforced GI. Conclusion: Nano zirconia reinforced glass ionomer and Nano hybrid resin composite have a similar clinical performance and wear resistance after one year follow up.

How the repair bonding strength of hybrid ceramic CAD/CAM blocks is influenced by the use of surface treatments and universal adhesives.

We examined how different methods of surface treatment and different universal adhesives with or without extra silane affected the repair bonding strength of hybrid ceramic CAD/CAM restorations. Cerasmart specimens (n=320) were subjected to thermocycling and assigned to the following surface pretreatment protocols: control, diamond bur (DB), hydrofluoric acid (HF), and tribochemical silica coating (TSC). Half the specimens received a coating of silane, followed by application of the universal adhesives Futurabond M+ (FMU), Tokuyama Universal Bond (TUB), Single Bond Universal (SBU), or Clearfil Universal Bond Quick (CUQ) (n=10). A hybrid composite resin was used to simulate repair; then the specimens underwent further thermocycling. Shear bond strength (SBS) was determined and modes of failure were examined. The TSC-CUQ silane (-) group showed the highest SBS values. The best repairs were obtained when the surface was treated with TSC, with the exception of the DB-TUB silane (-) group. TUB increased SBS more than the other adhesives. Additional silane decreased SBS in the HF-TUB and TSC-CUQ groups, while increasing it in the TSC-TUB and DB-FMU groups (p<0.05).

Development and characterization of kevlar and glass fibers reinforced epoxy/vinyl ester hybrid resin composites

AbstractThis research investigates the influence of kevlar and glass fiber reinforcements on the mechanical and thermal properties of epoxy/vinyl ester (hybrid resin) composite. The hybrid resin was synthesized by achieving an interpenetrating network between epoxy and vinyl ester. The composites were characterized using tensile, flexural, impact, and thermo‐gravimetric analysis (TGA). Scanning electron microscopy was employed to analyze surface morphology whereas Fourier‐Transformation Infrared Spectroscopy (FT‐IR) was used to investigate the possible interaction between the constituents of the composites. The findings have shown a notable improvement in the mechanical properties after the hybridization of the resin. For reference, the tensile strength of glass/hybrid resin and kevlar/hybrid resin composites were observed to increase by 8.33% and 23.65%, as compared to glass/epoxy and kevlar epoxy composites respectively, whereas, the bending strength of these composites was improved by 8.36% and 30.61%, respectively. TGA also showed an enhanced thermal stability of the hybrid resin‐based composites. Such improvements are noticed due to multi‐resin incorporation (the oxirane group of epoxy reacts with the hydroxyl group of vinyl ester), confirmed by the FTIR, TGA, and morphological analysis. This study signifies that the proposed hybrid composites are better in terms of strength and modulus relative to conventional metallic materials.Highlights The paper presents the development of novel hybrid resin, reinforced with synthetic fibers. Hybrid resin is imparted positively and is highly favorable in improving the mechanical properties of composites. The tensile strength of novel composites is increased by 8.33% and 23.65% relative to their base specimens, and a similar trend is observed in flexural and impact analysis. Fractured analysis showed that composite laminates deteriorated more intensely due to cohesive matrix fracture; adhesion failure was not observed at all, as evidenced by the emergence of micro‐cracks in resin. Developed novel composites exhibited maximum thermal stability; residual char in glass/epoxy/vinyl‐ester composite attained 17.81% higher, whereas kevlar/epoxy/vinyl‐ester achieved 3.56% relative to glass/epoxy and kevlar/epoxy base samples.

Exploration of Voids, Acoustic Properties and Vibration Damping Ratio of Cyperus Pangorei Rottb Fiber and Ramie Fiber Reinforced with Epoxy Resin Hybrid Composites.

Noise pollution is a major threat to the health and well-being of the entire world; this issue forces researchers to find new sound absorption and insulating material. In this paper, the sound absorption coefficient and vibration damping factor of panels manufactured from Cyperus pangorei rottb and ramie fiber reinforced with epoxy resin are explored. Cyperus pangorei rottb grass fiber and ramie fiber are widely available natural fibers. Cyperus pangorei rottb grass fiber is used in mat manufacturing, whereas ramie is widely used as a fabric. Using both of these fibers, six variant panels using a vacuum resin infusion process (VRIP) were fabricated. The panels were named C, R, CR, RCR-Flat, RCR-Curved, and RCR-Perforated. All the panels were tested for the sound absorption coefficient using an impedance tube with a frequency ranging up to 6300 Hz. Modal analysis was carried out by using the impulse hammer excitation method. A micro X-ray computed tomography (CT) scan was used to study the voids present in the panels. The results were compared among the six variants. The results show that the RCR-curved panel had the highest sound-absorbing coefficient of 0.976 at a frequency range between 4500 Hz to 5000 Hz. These panels also showed better natural frequency and damping factors. The presence of internal voids in these panels enhances sound absorption properties. These panels can be used at higher frequencies.

Manufacturing Accuracy, Intaglio Surface Adaptation, and Survival of Additively and Subtractively Manufactured Definitive Resin Crowns After Cyclic Loading: An In Vitro Study.

To assess the manufacturing accuracy, intaglio surface adaptation, and survival of resin-based CAD/CAM definitive crowns created via additive manufacturing (AM) or subtractive manufacturing (SM). A maxillary right first molar crown was digitally designed and manufactured using AM hybrid resin composite (VarseoSmile Crown Plus, Bego [AM-HRC]), AM glass filler-reinforced resin composite (Crowntec, Saremco Dental [AM-RC]), and SM polymer-infiltrated ceramic (Vita Enamic, VITA Zahnfabrik [SM-PICN]). Manufacturing accuracy (trueness and precision) was assessed by computing the root mean square (RMS) error (in μm; n = 15 per material). Intaglio surface adaptation was assessed by calculating the average gap distance (μm). Ten crowns from each group were cemented on fiberglass-reinforced epoxy resin dies and cyclically loaded to simulate 5 years of functional loading. One-way ANOVA, post hoc Bonferroni comparison tests, and Levene's test were used to analyze the data (α = .05). AM-RC had higher overall trueness than AM-HRC and SM-PICN (P ≤ .05), whereas the trueness of AM-RC on the external surface was similar to that of SM-PICN (P = .99) and higher than AM-HRC (P = .001). SM-PICN had lower precision than AM-RC and AM-HRC overall and at internal occlusal surfaces (P ≤ .05). Overall intaglio surface adaptation was similar between all groups (P = .531). However, for the axial intaglio surface, AM-RC and AM-HRC had higher adaptation than SM-PICN (P ≤ .05). All tested crowns survived the cyclic loading simulation of 5 years clinical use. AM-RC showed high manufacturing accuracy and adaptation. The tested resin-based CAD/CAM materials demonstrated clinically acceptable manufacturing accuracy and simulated medium-term durability, justifying the initiation of clinical investigations to determine their potential implementation in daily clinical practice.

Fracture Resistance and Failure Mode of Monolithic Zirconia, Veneered Zirconia, and Metal-Ceramic Full-Coverage Restorations: A Comparative In Vitro Study.

To evaluate and compare the fracture mode and strength of monolithic zirconia to veneered zirconia and metal-ceramic full-coverage restorations following artificial aging and to test the performance of translucent zirconia in terms of load-bearing capacity. Two mandibular first molars were prepared and scanned for their respective groups of full-coverage restorations. A total of 75 full-coverage restorations were fabricated and divided into five groups: two groups for monolithic zirconia, two groups for veneered zirconia, and one group for metal-ceramic. Then, 75 light-cured hybrid composite resin dies were fabricated to serve as abutments. Before cementation, all full-coverage restorations were subjected to accelerated aging. After cementation, all full-coverage restorations were subjected to compressive loading until fracture in an electromechanical universal testing machine. A two-way nested ANOVA and Tukey test were used to analyze the results with 95% confidence levels. Monolithic zirconia full-coverage restorations showed the highest mean fracture resistance of 4,201.0 N, followed by metalceramic full-coverage restorations of 3,609.3 N, and veneered zirconia full-coverage restorations showed the lowest mean fracture resistance of 2,524.6 N. The main mode of failure was cohesive bulk fracture for the monolithic zirconia group, cohesive/adhesive failure with infrastructure damage for the veneered zirconia group, and cohesive/adhesive failure without infrastructure damage for the metal-ceramic group. Monolithic zirconia full-coverage restorations showed superior resistance to fracture compared to metal-ceramic full-coverage restorations and are highly reliable in terms of load-bearing capacity within the posterior regions of the mouth.

POSS hybrid bioactive glass dental composite resin materials: Synthesis and analysis

IntroductionThis study create a dental composite by hybirding polyhedral oligo-sesquioxide nano monomers and bioactive glass BG 45S5. MethodsMake an experimental composite resin material with a 60 % filler content overall by substituting 20 % of the filler with BG 45S5. The experimental resins are grouped and named P0, P2, P4, P6 and P8 based on the reactive nanomonomer methacrylic acid-based multifaceted oligomeric sesquisiloxane (POSS) added by 2 %–8 % in the resin matrix portion of each group. Utilize a universal testing machine to analyze and compare the mechanical properties of these, then perform Fourier infrared spectrum analysis, double bond conversion analysis, and scanning electron microscope analysis. Based on this, after soaking the experimental materials artificial saliva solution or lactic acid solution for a while, the pH changes of the solution, the release of Ca2+ and PO43− ions, and the precipitation of apatite on the resin material's surface were tested and analyzed. Cell viability tests were used to assess sample cell viability and quantify the cytotoxicity of biological cells. The independent sample t-test was used to examine the group comparisons, and a difference was considered statistically significant at P<0.05. ResultsOutstanding mechanical and the double bond conversion are demonstrated by the nanocomposites when the POSS concentration hits 4 wt%. Agglomeration will cause the performance to deteriorate if the concentration beyond this threshold. In the P4 group, the double bond conversion, CS, and FS rose by a large margin, respectively, in comparison to the blank control group P0. Thankfully, the data demonstrate that adding POSS increases adhesive ability when compared to the blank group P0, however, there is no discernible difference between the other experimental groups. The acid neutralization capacity of the P4 group is essentially the same as that of the control group (P0). Ca2+ and PO43− ions are released in significant amounts following treatment with lactic acid solution, although this tendency is clearly less pronounced in artificial saliva. SEM and EDX data indicate that when the experimental resin is soaked in lactic acid solution and artificial saliva, apatite precipitation will happen on its surface. The results of the cell viability test indicated that there was no statistically significant difference between the experimental groups, and the viability of the cells increased after 24hours and 48 hours. ConclusionsPOSS was included into the composite resin along with 20% bioactive glass as a filler. When the proportion of POSS is less than 4%, the indices of composite resin materials rise in a dose-dependent way. When this value is surpassed, performance begins to deteriorate. The inclusion of POSS has no influence on the biological activity of the composites, which means that the hybrid composite resin is capable of acid neutralization, ion release, and apatite precipitation. Clinical SignificanceThe experimental composite resin can be used as an intelligent material in clinical treatment. It has the clinical application potential of preventing demineralization of tooth hard tissue, promoting remineralization, and improving edge sealing through apatite precipitation.

The effect of depth of cure on microhardness between bulk-fill and hybrid composite resin material

BackgroundFunctional properties should be considered when selecting composites for restorations. With bulk-fill resin composites, the disadvantages of conventional composites were overcome regarding the increments necessitating the application of a 2 mm thick layer of resin and the amount of polymerization. The most significant advantage of bulk-fill resin composite is the possibility of applying the material in 4 mm layers. Multiple studies have examined the polymerization, mechanical, and adhesive properties of bulk-fill resin composites and proven them successful. ObjectiveThis study aimed to compare the effect of the depth of cure on the microhardness between different bulk-fill composites and a hybrid composite material by following the manufacturer's instructions. MethodsIn this in vitro study, five composite types obtained from different companies were used: two high-viscosity bulk-fill composites, Filtek and OPUS bulk; two low-viscosity bulk-fill flowable composites, Any-com and OPUS flow; one light-cure hybrid composite, Cavex, totaling 25 samples. The composite was applied at a depth of 4 mm in the bulk-fill composite and 2 mm in the hybrid composite and light-cured. The microhardness was measured at three different times. The first time was performed immediately after light-curing, the second time was evaluated 24 h after polymerization, and the third time was after thermocycling. ResultA total of 25 samples showed that the microhardness increased the first and second times and decreased the third time after thermocycling on the top and bottom sides of Filtek, OPUS bulk-fill, OPUS flow, and Any-com bulk. The Cavex microhardness at the bottom was equal at all three-time points. Two-way repeated measures ANOVA showed that the microhardness between all types of composite resin materials was significantly different at different times when p = 0.00.

Influence of Treatments on the Mechanical Properties of Epoxy Resin Hybrid Composites Reinforced with Pineapple Fiber and Snail Shell Particulates

The growing environmental concern regarding synthetic materials in various engineering applications is driving increased research into the production of green composites. In this study, pineapple leaf fiber (PLF) and snail shell powder amended with sodium hydroxide (NaOH) solution, at concentration levels of 0, 2, 4, 6 and 8% for 30, 60 and 90 minutes, respectively, were used to produce various composite samples; and their mechanical properties tested in agreement with American Society for Testing and Materials (ASTM) International approved procedures. The laboratory test results revealed that both the NaOH concentration and treatment period considerably influenced the tensile and flexural strengths of the composite samples. It was observed that the composite samples, made with reinforcement materials modified with NaOH concentrations of 0%, 2%, 4%, 6%, and 8% for durations of 30, 60, and 90 minutes, exhibited tensile strengths of 8.12, 9.88, 11.04, 14.11, and 16.74 MPa; 10.93, 14.22, 17.04, and 15.71 MPa; and 12.27, 15.19, 14.06, and 13.84 MPa, respectively. Similarly, the results portrayed that the composite samples produced with reinforcement materials treated with 2%, 4%, 6% and 8% sodium hydroxide concentrations for durations of 30, 60 and 90 minutes, developed flexural strength of 31.98, 38.82, 43.97 and 49.03 MPa; 36.55, 44.17, 53.38 and 47.93 MPa; and 39.62, 46.08, 48.17 and 43.66 MPa, respectively. It was also interesting to observe that 6% NaOH treatment for 60 minutes yields the optimum tensile and bending strengths of 17.04 and 53.38 MPa respectively. This finding revealed the potential of using bio-composites for engineering applications, mostly where moderate tensile and flexural strengths characteristics are sought after.

CAD/CAM leucite-reinforced glass-ceramic for simulation of attrition in human enamel in vitro

ObjectiveInvestigate attrition simulation using CAD/CAM leucite-reinforced glass-ceramic antagonists on occlusal vs. buccal enamel. MethodsThree dental materials with known wear rates (resin-modified glass-ionomer, micro-filled, and fine particle composites) validated the wear simulator (CAD/CAM glass-ceramic antagonists, 200 cycles, 80 N load, deionised water irrigation, 0.7 mm sliding movement). Following this, human molars were sectioned into paired occlusal and buccal polished samples (n = 8/gp). Exposed 1.5 mm Ø enamel areas were subjected to attritional wear with and without pre-immersion in citric acid (5 min, 0.3%, pH 3.8). Profilometry measured step-height enamel wear and surface microhardness at different depths was calculated using Vickers indentation at 0.1 N and 0.5 N loads. ResultsDental material wear using the CAD/CAM antagonists showed consistency with previous data: mean (SD) resin-modified glass ionomer material loss of 177.77 (16.89) µm vs. 22.15 (1.30) µm fine particle hybrid composite resin wear vs. 13.63 (1.02) µm micro filled composite resin wear (P < 0.001). The coefficient of variation was less than 10%. Following validation, enamel sample wear was significantly increased when attrition was introduced (P < 0.001) independent of buccal vs. occlusal sample location (P < 0.05). Attrition resulted in occlusal wear of 26.1 ± 4.5 µm vs. buccal 26.3 ± 1.2 µm and attrition/erosion resulted in occlusal wear of 26.05 ± 4.46 µm vs. buccal 25.27 ± 1.16 µm. Whereas erosion-alone resulted in occlusal wear of 1.65 ± 0.13 µm and buccal 1.75 ± 0.03 µm. Microhardness testing at different loads revealed significantly greater hardness reductions in occlusal enamel vs. buccal enamel for 0.1 KgF indentations (P < 0.001) whereas in contrast 0.5 KgF indentations showed no differences. SignificanceWear simulation with CAD/CAM glass ceramic antagonists produced consistent wear in dental materials and human enamel, regardless of enamel surface origin. Lighter (0.1 KgF) hardness testing of occlusal vs. buccal origin revealed damage to the mechanical integrity of the superficial worn enamel.

Effect of Aging and Different Surface Treatments on Repair Bond Strength of Hybrid Resin Composites

Background: With the trend for minimally invasive dentistry and the rapid evolution of composite resin materials, repair of defective composite resin restorations is a popular choice rather than replacement of the restoration. The durability of the bond between the old and repaired composite restoration is important for a successful outcome. Objective: To evaluate the immediate and delayed shear bond strength of two types of repaired hybrid resin composites using different chemical and mechanical surface treatments. Methods: Two types of hybrid resin composites, micro-hybrid resin composite and nanohybrid resin composite, were used to prepare 288 pre-polymerized resin composite specimens. After polymerization, repair was done after 24 hours and 6 months. Each hybrid resin composite group was divided into 3 groups according to surface treatment used to repair the substrate: group 1: no surface treatment, group 2: treated by medium abrasive stone, and group 3: treated by fine abrasive stone. Each group was further subdivided into 3 subgroups according to different agents used for repair: group 1: Silane, group 2: Universal adhesive, and group 3: Silane + adhesive. Shear bond strengths of the repaired specimens were measured using a Universal testing machine. Failure modes were evaluated under a stereomicroscope. Results: Different chemical and mechanical surface treatments had a significant effect on the shear bond strength values of all groups (p ≤ 0.05). The highest mean shear bond strength values were found in nano-hybrid composites immediately repaired by silane after treatment by a medium abrasive stone while the lowest mean shear bond strength values were found in micro-hybrid composites with delayed repair and no surface treatment. Conclusion: Diamond burs using silane with adhesive improved the repair bond strength of the tested hybrid composites. In composite repair, using abrasive mechanical pretreatment followed by adhesive conditioning is crucial for the success of the repair restoration.

Development of almond shell powder and palm kernel fibre–reinforced cardanol oil toughened epoxy resin hybrid composites: mechanical, wear, and antimicrobial properties

Development of almond shell powder and palm kernel fibre–reinforced cardanol oil toughened epoxy resin hybrid composites: mechanical, wear, and antimicrobial properties

Investigation on mechanical properties of novel natural fiber-epoxy resin hybrid composites for engineering structural applications

Polymers and fibers are the main components of cementitious composite materials to reinforce concrete. The synthetic fibers used in concrete composites typically weigh and also, and they are easily subjected to thermal degradation. To tackle the above issues, researchers developed various natural fiber-based composites. In the paper, the mechanical characteristics of hybrid composites were examined. The hybrid composites were developed using Madar, Gongura, and Hibiscus cannabinus fibers. The polyester resin was the matrix. The fibers were treated chemically using a 5% sodium hydroxide (NaOH) solution. The fibers were then carefully cleaned with distilled water twice and baked for 70 min at 60 °C. For the evaluation of the tensile, flexural, and impact properties of the hybrid composites, specimens were made in accordance with ASTM standards. The treated composite sample (S3) specimen exhibits a tensile strength (TS) of approximately 34.720 N/mm2, flexural strength (FS) of 77.957 MPa, and flexural modulus (FM) of 1548.588 GPa. The average water absorption of the sample is only 2.45%. The hardness and impact strength (IS) of the samples are also superior to those of several other composites studied in the literature. Hence, the proposed hybrid composites could be a potential material for reinforcing the concrete composites to provide a higher service rate and greater durability to the structures.

One step polishing to compare the mean surface roughness of nanohybrid and microhybrid composite resins

Objectives: This study's goal was to compare the mean surface roughness of nano hybrid and micro hybrid composites using a one-step polishing method. This comparison was made based on the idea that a material with reduced surface roughness will exhibit superior perishability, aesthetics, surface &amp; optical properties, which means less wear, less staining, low plaque, and low caries rate. Methodology: This comparative study was carried out in April 2023 at the Ayub Medical College in Abbottabad, Pakistan, with a sample size of 100 (50 in each group), determined by the WHO calculator. Using a mechanical stainless steel template, 120 composite resin specimens mounted on acrylic blocks with dimensions of 2 mm x 3 mm x 3 mm were created. Results: 100 samples, separated into two groups, were used in this study. According to descriptive statistics, mean surface roughness and standard deviations for Nano hybrid composite in Group A were recorded as 0.076+0.025 and for Micro hybrid composite in Group B, they were 0.001+0.036. Conclusion: After polishing with a one-step procedure, there is a noticeable difference between the surface roughness of nano hybrid and micro hybrid composite resins, indicating that the former has higher polish ability than the latter.

Bond strength of additively manufactured composite resins to dentin and titanium when bonded with dual-polymerizing resin cements

Statement of problemAdditively manufactured composite resins for definitive restorations have been recently introduced. The bond strength between these composite resins and different substrates has not been extensively studied. PurposeThe purpose of this in vitro study was to measure the shear bond strength (SBS) between additively manufactured composite resins and dentin and titanium substrates and compare those with the SBS between subtractively manufactured polymer-infiltrated ceramic and the same substrates (dentin and titanium), when different dual-polymerizing resin cements were used. Material and methodsOne hundred and eighty cylinder-shaped specimens (Ø5×5 mm) were prepared from 3 materials recommended for definitive restorations: an additively manufactured composite resin (Crowntec [CT]); an additively manufactured hybrid composite resin (VarseoSmile Crown Plus [VS]); and a subtractively manufactured polymer-infiltrated ceramic (Enamic [EN]) (n=60). Specimens were randomly divided into six subgroups to be cemented to the two substrates (dentin and titanium; n=30) with 1 of 3 resin cements (RelyX Universal, Panavia V5, and Variolink Esthetic DC) (n=10). The restoration surface to be bonded was treated according to the respective manufacturer’s recommendations. Dentin surfaces were treated according to the resin cement (Scotchbond Universal Plus Adhesive for RelyX Universal, Panavia V5 Tooth Primer for Panavia V5, and Adhese Universal for Variolink Esthetic DC), while titanium surfaces were airborne-particle abraded, and only the specimens paired with Panavia V5 were treated with a ceramic primer (Clearfil Ceramic Primer Plus). SBS was measured in a universal testing machine at a crosshead speed of 1 mm/min. Failure modes were analyzed under a microscope at ×12 magnification. Data were analyzed by using 2-way analysis of variance and Tukey honestly significant difference tests (α=.05). ResultsWhen SBS to dentin was considered, only restorative material, as a main factor, had a significant effect (P<.001); EN had the highest SBS (P<.001), while the difference in SBS values of CT and VS was not significant (P=.145). As for SBS to titanium, the factors restorative material and resin cement and their interaction had a significant effect (P<.001). Within each resin cement, EN had the highest SBS to titanium (P<.001), and within each restorative material, Variolink resulted in the lowest SBS (P≤.010). Overall, EN and RelyX were associated with the highest SBS to titanium (P≤.013). Mixed failures were predominant in most groups. ConclusionsRegardless of the substrate or the resin cement used, the subtractively manufactured polymer-infiltrated ceramic had higher shear bond strength than the additively manufactured composite resins. The SBS of the additively manufactured composite resins, whether bonded to dentin or titanium, were not significantly different from each other. Regardless of the restorative material, Variolink DC resulted in the lowest SBS for titanium surfaces.