Fill Resin Research Articles

Influence of restorative material translucency on the chameleon effect

Blending of artificial restoration materials to the natural tooth is challenging. Beyond just color, optical properties, particularly translucency, substantially influence the final appearance. The more chameleon effect that the restorative materials exhibit, the more natural looking restorations. The purpose of this study is to investigate the influence of restorative material translucency on the chameleon effect. Five types of resin composite in three different shades as well as one shade of conventional glass ionomer cement were fabricated into disks. To analyze the chameleon effect, glass ceramic blocks were milled to create four wells in each block. The restorative materials were filled into the wells. The color was measured with CIE L*a*b* every 6 months. Statistical analysis was conducted using Two-Way Repeated Measures ANOVA. The material with the highest translucency was flowable resin composite. The high translucency materials exhibited an immediate chameleon effect, as did the bulk-fill resin composites, which are low translucency. Both high and low translucency materials exhibited a delayed chameleon effect for 3 years, except for the bulk fill resin composites. The translucency of the restorative materials had a 68% positive correlation with their chameleon effect. The age of the restoration is one important factor influencing the color blending.

Mechanically strong, thermostable, and flame-retardant composites enabled by Brown paper made from bamboo

We design a facile strategy to manufacture a high-performance composite of polyvinyl chloride (PVC) made from brown paper and PVC film. Brown paper with little fiber damage is prepared using bamboo pulping via a moderate method, and a high content of lignin enhances the lipophilicity of the fibers. The "layer-network" porous paper provides “green” framework support. When hot and cold pressing of the stacks of paper sheets and PVC films is performed, PVC resin fills the pores of the framework support, and then, strong mechanical interlocking structures are established, similar to the vastly distributed microscale "mortise riveting". Then, a dense and lightweight paper/PVC composite is produced. The composite exhibits strong mechanical properties in terms of tensile strength (132.65 MPa), flexural strength (183.45 MPa), flexural modulus (10.44 GPa), and internal bonding strength (2.6 MPa), with good thermal stability and flame resistance. The strength is 5- to 10-fold that of commercial artificial boards, substantially surpassing that of bamboo, PVC, and other PVC composite resin profiles. Additionally, PVC replaces adhesives that contain or release formaldehyde, and a high percentage (>60 wt%) of green cellulose fibers is used. The simple technology directly uses existing manufacturing methods of papermaking, film stretching, and press laminating systems. Therefore, the high-performance paper/PVC composite is environmentally sustainable and more cost-effective than PVC composites prepared with other fillers. The new materials have great potential prospects for the development of high-strength materials and the implementation of carbon neutrality in prefabricated houses, furniture, vehicles, ships, containers, and color steel plates.

Evaluation of Micro-Tensile Bond Strength of Fibre Post with Titanium Dioxide Nanoparticles as Fillers in Experimental Dental Composite Resin.

Background: The clinical success of post-core restorations is determined by the composite utilized and the strength of the post-core adhesion. The effectiveness of titanium dioxide nanoparticles (TiO2 NPs) as a multifunctional material with photo-induced activities and better mechanical characteristics are observed as particle size is reduced to under 50 nm. Aim: The purpose of this study is to determine the bond strength of fibre-reinforced composite (FRC) posts with TiO2 NP as fillers and to compare it with conventional composite resin core material. Materials and Methods: 30 single-rooted mandibular premolars were selected and routine root canal procedures were done. A quantity of 5% TiO2 NPs were synthesized and added as silanized filler to the experimental composite resin. Post space was prepared and fibre-reinforced composite (FRC) post luting was performed. The specimens were then grouped into the following groups: Group I consisted of the experimental composite resin containing 5% TiO2 fillers, Group II consisted of core X flow, and Group III consisted of Multicore Flow. All test groups were submitted for thermocycling. After this, the samples were tested for micro tensile bond strength. A stereomicroscope with a magnification of 20× was used to examine the fractured surfaces. The data were analysed using one-way ANOVA and Tukey HSD tests. Results: Statistical analysis revealed that Group I showed the highest mean bond strength value of 35.6180 Mpa. The results obtained with Group III showed the lowest mean bond strength value of 19.4690 Mpa. Adhesive failures were identified by stereomicroscopy of the fractured surfaces. Conclusion: The experimental composite resin comprising 5% TiO2 NP had a greater bond to the FRC post than other materials tested.

Evaluation of microtensile bond strength of nanoclay modified adhesive systems using bulk fill resin composite

Background: Composite polymerization creates internal stresses that cause bond loss at the tooth composite interface, cuspal deflection, and enamel crack formation; that are potential restoration failure. Aims: The aim of the present study was to evaluate micro-tensile bond strength of bulk-fill resin composite to human dentine of extracted teeth using nanoclay modified adhesive system (with and without organic modifier). Materials and Methods: A total of 120 caries-free permanent human posterior teeth were used and classified three groups according to adhesive system (each with 40 teeth); including Prime&Bond universalTM, Dellite®43B and Dellite®LVF modified adhesive systems. Each group was subdivided into two equal subgroups whether thermocycling was conducted or not. Results: Result revealed that there was a significant difference in mean microtensile bond strength of the three tested materials The best results achieved by Dellite®43B followed by Dellite®LVF modified adhesive system finally conventional Prime&Bond universal adhesive system. Difference in Microtensile bond strength between thermocycled and Nonthermocycled was highly significant. Conclusion: Addition of Nanoclay (montmorillonite) with organic modifier to universal adhesive material is valuable to augment the bond strength of bulk fill resin composite to human dentition. (2) Thermocycling adversely affect the bond strength of nanoclay /adhesive system complex to tooth tissue.

Determination of microhardness of bulk-fill resins at different depths.

The aim of this study was to determine Vickers microhardness (HV) in bulk fill resins at different depths. Test specimens were prepared with different bulk fill resins: Filtek Bulk-Fill (3M ESPE) [FBF], Surefill SDR flow (Dentsply) [SDR], Fill-UP (COLTENE) [FU] and Surefill (Dentsply) [SF]. Semi-cylindrical test specimens were prepared in a mold 6 mm in diameter and 4 mm thick (n=5). A 1000 mW/cm2 light curing unit was applied (Coltolux LED - Coltene) for 20 seconds. HV was determined with three indentations (Vickers Future Tech FM300, 300 g, 8 s) at four depths: 1, 2, 3 and 4 mm from the top surface to the interior. Data were recorded immediately (t0) and 24 hours later (t24). Results were analyzed with two-way ANOVA (p<0.05), and multiple comparisons were performed using Tukey's test. Mean and SD of HV at t0 for each mm were: [FBF] t0: 49.23(4.65) / 48.32(3.36) / 44.38(2.06) / 40.59(2.58); [FBF] t24: 61.37(3.47) / 62.63(3.03) / 57.27(5.22) / 56.37(5.88);[SDR]t0:27.81(3.13) / 28.07(2.4) / 27.24(2.94) / 25.71(3.0); [SDR] t24: 35.11(2.16) / 35.17(1.96) / 35.53(1.81) / 33.18(2.08); [FU] t0: 41.43(1.41) / 39.87(0.88) / 38.11(1.81) / 39.09(1.92); [FU] t24: 49.27(1.54) / 48.77(1.77) / 48.65(1.88) / 46.76(4.93); [SF] t0: 71.35(7.09) / 67.39(9.76) / 68.95(6.21) / 64.1(8.35); [SF] t24: 76.06(6.61) / 75.31(9.37) / 75.2(11.57) / 69.81(12.14). ANOVA showed significant effect of material, depth and recording time (p<0.05), and Tukey's test showed that recording sites (depths) differed significantly, giving four homogeneous groups. Under the conditions of this study, it can be concluded that microhardness of bulk-fill resins can be affected by depth and post-curing time.

DYNAMIC AND BALLISTIC PERFORMANCE OF GLASS/CARBON FIBER/ALUMINUM 1100 WIRE MESH REINFORCED COMPOSITE

Increase in the demand for high-performance and lightweight structural materials in the automobile and aircraft industries may inspire a strong tendency to develop fiber metal laminates (FMLs). In this work, the FML composites are fabricated using different stacking sequences of glass/carbon fibers, aluminum wire mesh, BaSO4 filler and epoxy resin. Six different combinations of composites with different stacking sequences and wire mesh angles are fabricated using the hand-lay technique. Dynamic mechanical analysis (DMA), ballistic and wear experiments were used to investigate the fabricated composites’ performance. The FML6 Al wire mesh with BaSO4 filler increases the storage modulus by 16.12% and enhances the energy absorption capacity by 3.19%. From the ballistic, the carbon fiber composite (FML3) shows 4.47% improvement compared to the glass fiber composite (FML1) for the same 90∘ wire mesh orientation.

Clinical evaluation of direct resin composite restorations of endodontically treated molars using dual cured self-adhesive system with bulk fill composite versus incremental packing technique

Restoration after endodontic treatment is as important as root canal therapy for clinical success. Evolution of adhesive dentistry strongly aided in the conservation of tooth structure and reinforcement of the restored teeth. Self-etch adhesives has evolved aiming to reduce the technique sensitivity and simplifying the steps needed for bonding (one or two steps). Dual cured self-etch adhesives were also introduced to be more chemically compatible with the resin composite restorations. Bulk-fill resin composites has also achieved great popularity due to the ease of application and being more time saving. These materials made the direct restoration of endodontically treated teeth more conservative, time saving and reliable. This research was performed to assess the clinical success of the restorations of the endodontically treated molars with remaining three walls restored using self-etch adhesives and bulk fill resin composite in comparison to conventional nanohybrid resin composite at a time intervals of 1week (baseline) , 3 ,6 and 12 months. In a randomized clinical trial, 40 patients with endodontically treated molars with remaining three walls received a restorative intervention with either (Xtra-Fil) bulk fill resin composite or (Grandio) nano hybrid resin composite applied in incremental technique.

Fracture Resistance of Endodontically Treated Upper Premolar Teeth Restored With Bulk Fill And Conventional Resin Composite

Objectives: The aim of this in vitro study was to evaluate the fracture resistance of endodontically treated upper premolar teeth restored with different resin composites. Materials and Methods: Hundred and eight maxillary premolar teeth were randomly divided into nine groups (n=12). The teeth in the first group were left intact and tested as unprepared group 1 (negative control) (group 1). Other eight groups were prepared with MOD cavities and endodontically treated. The teeth in group 2 (positive control) were unrestored. Other groups were restored with different resin composites. Group 3: conventional resin composite and group 4-9 six bulk fill resin composite (group 4: 3M Filtek Flowable Bulk Fill, group 5: 3M Filtek Posterior Bulk Fill, group 6: Voco X-tra base, group 7: Voco X-tra fil, group 8: Dentsply SDR Flow, group 9: Dentsply Quixfil). Single Bond Universal was applied as self-etch, according to application instructions. The restored teeth were stored in distilled water for 24 hours at 37°C. Compressive force was applied parallel to the long axis of the teeth. The test was carried out at a speed of 1mm/min. ANOVA and Tukey HSD tests were used in the analysis of the data (p,0.05). Results: Conventional resin composite (group 3) showed lower fracture resistance than bulk fill resin composites (p&amp;lt;0.05) . There was no significant difference between the groups restored with bulk fill composites (p≥0.05). Conclusions: The bulk fill composites increase the fracture resistance of endodontic treated teeth,

Effect of Marble Dust on the Mechanical, Morphological, and Wear Performance of Basalt Fibre-Reinforced Epoxy Composites for Structural Applications.

The reinforcement of natural fibre and fillers in polymer resin is the latest trend followed by research groups and industries for the development of sustainable composites. Basalt fibre and waste marble powder are naturally occurring substances used to enhanced polymer properties. The present research examined the effect of both basalt fibre and waste marble powder in epoxy resin. The hand lay-up method was employed to fabricate the composite and test for mechanical and wear behaviour. The tensile, flexural, and impact energy were enhanced up to 7.5 wt. % of WMP, and the Vickers hardness of epoxy enhanced every state of reinforcement of WMP. The specific wear rate was observed to be increased with the addition of WMP until 7.5 wt. %. Scanning electron microscopy was performed to examine the nature of fractured surface wear phenomena.

Effect of the Addition of Thermoplastic Resin and Composite on Mechanical and Thermal Properties of Epoxy Resin.

When the thermoplastic composites reach the service limits during the service, the recovery and utilization are the key concerns. Meanwhile, the improvement of strength, toughness and durability of epoxy resin is the effective method to prolong the service life of materials and structures. In the present paper, three kinds of thermoplastic resins (polypropylene-PP, polyamide 6-PA6 and polyether-ether-ketone-PEEK) and composites (carbon fiber-PEEK, glass fiber-PA6 and glass fiber-PP) were adopted as the fillers to reinforce and toughen the epoxy resin (Ts). The mechanical, thermal and microscopic analysis were conducted to reveal the performance improvement mechanism of Ts. It can be found that adding thermoplastic resin and composite fillers at the low mass ratio of 0.5~1.0% brought about the maximum improvement of tensile strength (7~15%), flexural strength (7~15%) and shear strength (20~30%) of Ts resin. The improvement mechanism was because the addition of thermoplastic fillers can prolong the cracking path and delay the failure process through the load bearing of fiber, energy absorption of thermoplastic resin and superior interface bonding. In addition, the thermoplastic composite had better enhancement effect on the mechanical/thermal properties of Ts resin compared to thermoplastic resin. When the mass ratio was increased to 2.0~3.0%, the agglomeration and stress concentration of thermoplastic filler in Ts resin appeared, leading to the decrease of mechanical and thermal properties. The optimal addition ratios of thermoplastic resin were 0.5~1.0% (PEEK), 1.0~2.0% (PA6) and 0.5~1.0% (PP) to obtain the desirable property improvement. In contrast, the optimal mass ratios of three kinds of composite were determined to be 0.5~1.0%. Application prospect analysis indicated adding the thermoplastic resin and composite fillers to Ts resin can promote the recycling and reutilization of thermoplastic composites and improve the performance of Ts resin, which can be used as the resin matrix, interface adhesive and anti-corrosion coating.

Graphene as reinforcing filler in polyvinyl acetate resin

Graphene gel and powder were added to polyvinyl acetate (PVA) resin to investigate its potential improving effects on shear strength of the resin. Graphene flakes were synthesized based on a simultaneous electrochemical exfoliation/deposition procedure. Flakes were decorated in face with magnetic nanocrystals in hetero-structure. They were mixed with PVA resin at 3% content, based on the wet weight of the resin. Beech wood specimens (Fagus orientalis L.) were prepared according to ASTM D143-14. Separate sets of specimens were prepared to be first heated at 165 °C and 185 °C for 4 h. Results demonstrated significant improving effect of graphene powder on shear strength of PVA resin. Graphene gel did not improve shear strength due to dilution of resin. Density functional theory simulations indicated very low adsorption energy of either pure graphene (−0.45 eV) or Ni-doped graphene (−0.91 eV) flakes on cellulose. Therefore, the improving effect was not attributed to formation of new bonds between graphene flakes and cell-wall polymers. It was concluded that graphene powder acted as a reinforcing filler in the PVA resin matrix, significantly improving its shear strength in the un-heated beech specimens. However, as a result of thermal degradation of cell-wall polymers and the consequent decrease in mechanical properties of the wood, as well as a considerable decrease in wood wettability, failures occurred within the wood structure of the heat-treated specimens rather than within the bond line. Therefore, graphene powder could not improve the overall shear strength in the heat-treated specimens at 185 °C.

Effects of C-Factor on Bond Strength of Universal Adhesives to Floor and Wall Dentin in Class-I Composite Restorations.

To evaluate the effects of C-factor on the bond strength of universal adhesives to floor and wall dentin in class-I composite restorations using a bulk-fill composite. 108 non-carious humans third molars were randomly divided into four groups as follows: flat wall, flat floor, cavity wall, and cavity floor (n = 36). Then, each group was subdivided into three subgroups according to the type of adhesive used: Single Bond Universal, G-premio Bond (both universal adhesives), or Adper Single Bond 2 (an etch-and-rinse adhesive). After the bonding procedure, X-tra fill resin composite was applied in bulk to build up the flat surfaces or fill the cavities.Then the teeth were sectioned into 1-mm2 sticks and microtensile bond strength (µTBS) was measured using a universal testing machine. µTBS (MPa) was analyzed by one-way, two-way, and three-way ANOVA using SPSS Version 23 (a = 0.05). Interactions between adhesives and bonding surfaces, as well as C-factor and bonding surfaces showed statistically significant differences, but the interaction between the C-factor and type of adhesive was not statistically significant. The comparison of bonded surfaces including the flat wall and the flat floor in Adper Single Bond 2 was statistically significant (p < 0.05), except for the cavity wall and cavity floor. Regardless of the type of adhesives, the C-factor reduced the µTBS of the composite resin to dentin. Adper Single Bond 2 mediated higher µTBS than did the universal adhesives G-premio Bond and Single Bond Universal.

Controlling factors of the particle size of spherical silica synthesized by a dry process

AbstractSilica is an important inorganic compound used in many materials, including quartz products and resin fillers. To synthesize silica by a dry process, combustion methods using organosilicon compounds as raw monomers have been extensively studied. However, few studies have considered mass production or compared preparation methods using different types of organosilicon compounds and the same equipment. In this study, we used six starting materials in a dry process and examined the effect of monomer species on particle shape and size. The amount of raw monomer supplied was adjusted so that the calorific value of combustion was the same for all the raw monomers. We focused on the calorific value because it affects the construction cost of industrial‐scale production plants. For example, when the calorific value is high, the manufacturing plant is large and costly because the heat generated after the reaction must be removed. We obtained spherical silica particles by a dry process using six monomers. The particle size depended on both the basic unit of the monomer and the required oxygen (RO) ratio of the primary burner gas. This combination was essential in determining the speed of the initial reaction, number of nuclei, and residence time. Consequently, we established a factor that determines the size of spherical silica particles and successfully adjusted the particle size.

Study on Preparation and Properties of Ultrahigh Molecular Weight Polyethylene Composites Filled with Different Carbon Materials.

The development of ultrahigh molecular weight polyethylene (UPE) has been restricted due to its linear structure and low thermal conductivity. In this paper, graphene oxide (GO) was prepared by the modified Hummers method, and then UPE/reduced graphene oxide (rGO) powder was prepared by reduction with hydrazine hydrate. UPE/natural graphite (NG), UPE/carbon nanofiber (CNF), and UPE/rGO are prepared by hot compression molding. With the increase of thermally conductive fillers, the high density of the composite makes the thermal conductivity of the crystal structure more regular and the thermal conductivity path increases accordingly. Both TGA and SEM confirmed the uniform dispersion of carbon filler in epoxy resin. Among the three composites, UPE/NG has the best thermal conductivity. When the NG filling content is 60 phr, the thermal conductivity of the UPE/NG composite is 3.257 W/(mK), outperforming UPE/CNFs (0.778 W/(mK) and pure UPE (0.496 W/(mK) by 318.64 and 556.65%, respectively. UPE/CNFs have the best dielectric properties. Comparison of various carbon fillers can provide some references for UPE’s thermal management applications.

Stress–strain behavior of rock mass around the roadway with roof support of rock fall-hazardous zones by the phenolic resin fill

The authors discuss roadway heading and support in unstable rock mass. The stress–strain analysis is performed for rocks and mine support system when voids generated by rock falls in roof and sidewalls of a roadway are filled with phenolic resin. The change in the stresses when the zone of rock fall-hazardous zone in the roadway roof grows in height is shown.

Superhydrophobic Composite Coating with Excellent Mechanical Durability

Superhydrophobic surfaces have great potential for self-cleaning, anti-icing, and drag-reducing because of their water repellency property. However, their super-hydrophobicity is destroyed under mechanical abrasion due to the vulnerability of the delicate surface textures. Here, we demonstrate a strategy to create a robust superhydrophobic surface using MXene and fluoridated silica as functional fillers in epoxy resin. The fluoridated silica produces low surface energy, MXene serves as a wear-resistant phase and epoxy resin is the binding matrix. The composite coating demonstrates a self-cleaning effect to remove particles from the superhydrophobic surface by rolling water droplets. Moreover, the coating exhibits excellent mechanical durability by standing abrasion to maintain super-hydrophobicity. The superhydrophobic composite coating has the advantages of low cost and feasibility and has the potential for expandable industrial promotion.

The effect of contemporary finishing and polishing systems on the surface roughness of bulk fill resin composite and nanocomposites.

To evaluate the effects of various finishing and polishing (F/P) systems regarding the surface roughness (Ra ) value of two nanocomposites and a bulk fill resin composite. Three resin composites (Filtek Z550, Filtek Ultimate Body, Filtek Bulk Fill Posterior) were tested. Forty disk-shaped specimens of each material were cured under Mylar strip and then randomly divided into four subgroups according to the F/P method (n=10): Control, Sof-Lex Spiral Wheels, Astropol, and Clearfil Twist Dia. Ra values was measured and the surfaces were examined under scanning electron microscope. The data were analyzed by generalized linear models (p < 0.05). The Filtek Bulk Fill Posterior had the highest Ra value while Filtek Ultimate Body was the resin composite with the lowest roughness (p < 0.05). Considering the average Ra values after polishing, while the lowest Ra in all groups was obtained with the control group, the Clearfil Twist Dia showed similar Ra to the control group (p > 0.05). The samples polished with Sof-Lex Spiral Wheels had the highest Ra (p < 0.05). In addition to the resin composite type, the F/P technique greatly affected the Ra value of resin composite. The nanocomposites exhibited with the lowest Ra compared to the bulk fill resin composite after F/P. It was observed that the diamond containing-polishing system created smoother surfaces than the aluminum oxide containing- and silicon carbide containing-polishing systems. In terms of Ra , the nanocomposites exhibited better performance than the bulk fill resin composites. Nowadays, newly developed polishing systems containing diamonds can be successful at a comparable level to existing polishing systems. For this reason, these systems are preferable for polishing both nanocomposites and bulk fill resin composites.

Study Of Manufacturing Composite Particle Boards of Sago/Rumbia Leaf (Gaba-Gaba) Using Epoxy Filler and Fiberglass Filler on Physical Properties of Composites

The current development of science and technology, especially in the field of materials, causes people to prefer to use instant construction materials because they are practical, solid and durable, and easy to obtain, so that people, especially sago/rumbia processing farmers, only use the contents of the stems as flour. In contrast, the -other parts of sago/rumbia are no longer used, so they become waste. Research on particle composite materials and sago/sago leaf stalk fibers, using resin fillers and fiberglass catalysts, as a study on the manufacture of composite boards to compare with previous studies using epoxy fillers and fiberglass filler studies to see the ability of physical and economic properties to manufacture boards. Composites in previous studies. This study uses a testing method using the standard SNI 03-2105-2006 [1].

Effects of Adjacent Tooth Type and Occlusal Fatigue on Proximal Contact Force of Posterior Bulk Fill and Incremental Resin Composite Restoration.

To measure the proximal contact force in newtons (N) between incremental and bulk fill class II resin composite restorations and implant molar teeth or adjacent premolar teeth with simulated periodontal ligament. The model used was created with a typodont first molar tooth with two bilateral occlusal-proximal class II cavities, an adjacent tooth simulating an implanted molar tooth (Titamax CM, Neodent, Curtiba, PR, Brazil) and a premolar with simulated periodontal ligament. Two resin composite restorative techniques were used: Inc-Z350XT, (Filtek Z350, 3M Oral Care, St. Paul, MN, USA) inserted incrementally and Bulk-OPUS, (Opus Bulk Fill APS, FGM, Joinville, SC, Brazil) high viscosity bulk fill resin composite (n=10). As a control, a typodont having intact teeth without restorations was used. After the restorative procedure, each specimen was radiographed using a digital system (Dürr Dental, Bietigheim-Bissingen, Germany). The proximal contact force (N) was measured using dental floss with a microtensile machine (Microtensile ODEME, Luzerna, SC, Brazil). The specimens were then subjected to mechanical fatigue cycling to simulate 5 years of aging. All the parameters were measured after aging. The X-rays were blindly qualitatively analyzed by two operators to identify the loss of proximal contact. One-way ANOVA was used for comparing the initial contact force between restored and intact teeth. Two-way ANOVA followed by Tukey testing was performed for contact area data and for the contact force/contact area ratio. The proximal contact force data were analyzed using one-way repeated measurement ANOVA followed by Tukey testing (α=0.05). The X-ray proximal contact analyses were described by the frequency. The initial proximal contact force was similar for intact and restored teeth. The contact force and contact area with the molar were significantly higher than with the premolar; however the contact force/contact area ratio was similar for all tested groups. The bulk fill technique showed a contact force similar to the incremental filling technique. Fatigue resulted in a significant reduction in the proximal contact force (p<0.001), irrespective of the region analyzed or restorative material used. The digital X-rays detected no alteration in the proximal contact after occlusal fatigue. Larger contact area resulted in higher proximal contact force. Proximal contact force decreased with 5 years of simulated occlusal fatigue. The bulk fill technique showed a proximal contact force similar to that of the incremental filling technique.

Torsion modulus with CaCO3 fillers in unsaturated polyester resin - mechanical spectroscopy

This work presents an alternative to studying and determining the torsion modulus, G, in composites. For this purpose, we use a measuring system with a rotation motion sensor coupled with a torsion pendulum that allows for determining the angular position as a function of the time. Then, through an equation derived from mechanical spectroscopy studies that permits the calculation of G’s value, the experiments focus on samples of different quantities of calcium carbonate (CaCO3) in unsaturated polyester resins. The results show that CaCO3 (33.33%W) fillers increase G’s value by 88% compared with unsaturated resin (100%W). Furthermore, there is a density increase of approximately 21% with the addition of CaCO3, considering the same two samples, which makes these composites the most massive. The relationship between G and composite density shows that it is possible to change the amount of CaCO3 to increase torsion resistance values in a controlled way.