{"paper_id":"437aed3a-5a12-42b6-bf56-0cf644ea370f","body_text":"Enhancement of Flexural Strength in Polymethylmethacrylate (PMMA) Through the Incorporation of Graphene Nanoparticles: A Comparative In Vitro Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Enhancement of Flexural Strength in Polymethylmethacrylate (PMMA) Through the Incorporation of Graphene Nanoparticles: A Comparative In Vitro Study Divyabharathi Selvam, Karthikeyan Vasudevan, Noorul Rizwana, Deepika Selvam This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5007376/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Polymethylmethacrylate (PMMA) is a common material in dental prosthetics, but its mechanical limitations, particularly in flexural strength, can affect its performance. Graphene nanoparticles, known for their exceptional mechanical properties, present a potential solution to enhance PMMA’s strength. Aim This study investigates the impact of incorporating graphene oxide (GO) and reduced graphene oxide (RGO) nanoparticles into PMMA on its flexural strength, comparing the effects of different nanoparticle concentrations. Materials and Methods Seventy heat-polymerized PMMA specimens (65 × 10 × 3 mm) were prepared following ISO 1567 standards. These specimens were divided into three groups: Control (no nanoparticles), Experimental Group A (GO), and Experimental Group B (RGO). Each experimental group was further subdivided based on the nanoparticle concentration: 0.10g, 0.20g, and 0.30g. Flexural strength was measured using a three-point bending test on a Universal Testing Machine with a crosshead speed of 1.50 mm/min and a span length of 40 mm. Data were analyzed using ANOVA and post-hoc Tukey-HSD tests. Results The control group recorded a mean flexural strength of 49.25 N. Incorporating GO and RGO nanoparticles significantly improved PMMA's flexural strength, with the highest strength observed in the RGO 0.30g group, showing a mean value of 213.6 N. Conclusion Reinforcing PMMA with graphene nanoparticles, including GO and RGO at various concentrations, significantly enhances its flexural strength compared to unreinforced PMMA. These findings highlight the potential of graphene-based nanoparticles to improve the durability of dental materials, offering superior mechanical properties critical for long-term clinical use. Flexural strength graphene oxide reduced graphene oxide nanotechnology polymethylmethacrylate Introduction Polymethylmethacrylate (PMMA) is one of the most widely used materials in dentistry, valued for its stability in the oral environment, ease of manipulation, polishability, and cost-effectiveness when used with standard equipment. [1] PMMA is extensively utilized in the fabrication of prostheses and orthodontic appliances. Since its introduction, there has been a continuous effort to enhance the mechanical properties of acrylic resins, particularly their flexural strength. The limited flexural strength of PMMA has been attributed to its brittle nature at its glass transition temperature of approximately 110°C 3 and its susceptibility to cyclic loading. Fracture of the denture material remains the primary mode of clinical failure.Flexural strength, also known as the modulus of rupture, bend strength, or fracture strength, is a critical mechanical parameter for brittle materials. It refers to a material’s ability to resist deformation under load. The transverse bending test is commonly employed, where a rod specimen with a circular or rectangular cross-section is bent until it fractures using a three-point flexural test technique. The flexural strength represents the highest stress the material experiences at its moment of rupture, measured in terms of stress (σ).Numerous experiments have been conducted to improve the flexural strength and overall mechanical properties of PMMA. Reinforcing PMMA with materials such as glass fibres [6], sapphire whiskers, aramid fibres, carbon fibres, metal wires , nylon, polyurethane fibres and zirconia has led to significant improvements in its fracture resistance. Despite these advancements, there remains a need for further enhancement.Nanotechnology, a rapidly growing field, is poised to shape the future of science, medicine, and technology. The term \"nano\" is derived from the Greek word for “dwarf,” and nanotechnology involves the manipulation of matter at the scale of billionths of a meter, or nanometers—roughly the size of two or three atoms. Nanoparticles are increasingly used in material science for their wear resistance and anti-corrosion properties. The principle behind the use of nanoparticles in PMMA is that altering the filler size can enhance both the polishability and fracture resistance of the material. Among the various nanoparticles explored, graphene oxide (GO) has shown promise due to its unique properties.Graphene oxide, a derivative of graphene, is a two-dimensional, single-layer structure of sp2-hybridized carbon atoms arranged in a hexagonal configuration. It has been extensively studied for its potential to enhance the performance of materials, thanks to its exceptional physicochemical, optical, and mechanical properties. GO's outstanding mechanical properties, chemical stability, biocompatibility, and antibacterial effects contribute to reduced wear and friction. Despite being only a single atomic layer thick, GO is remarkably strong—200 times stronger than steel. Recent studies have highlighted that GO and graphene-based composites possess a range of beneficial characteristics, including a large surface area, excellent elasticity and ductility, good biocompatibility, and exceptional mechanical strength. [2,3] While research and development of graphene oxide-based dental biomaterials are still in their early stages, these materials' distinctive properties and potential for functionalization with biomaterials suggest numerous unique clinical applications. However, this emerging field of nanotechnology requires further experimentation before it can be widely employed in clinical settings. Thus, this study was undertaken to evaluate whether incorporating graphene oxide into PMMA increases its flexural strength. Additionally, the study aims to compare the effects of different concentrations of graphene oxide and reduced graphene oxide on the flexural strength of PMMA. Materials and Methods Materials Polymethylmethacrylate (PMMA) Resin, Graphene Nanoparticles, Dispersion Equipment, Polymerization Equipment, Mixing Tools, Molds, Precision Scales ,Mechanical Testing Equipment, these materials are essential for preparing and testing PMMA samples reinforced with graphene nanoparticles, and for conducting a comprehensive evaluation of their mechanical and aesthetic properties. Methods Sample Preparation Seventy specimens, each with dimensions of 65 × 10 × 3 mm according to ISO 1567 standardization [4], were prepared from clear heat-polymerizing acrylic resin. Forty wax patterns of the specified dimensions were created and invested in flasks using the capping technique (2-pour technique) with dental plaster. Once the investing material had set, the flasks were dewaxed in a conventional water bath. After dewaxing, the flasks were opened, cleaned to remove any residual wax, and a separating medium (cold mold seal) was applied to protect the gypsum surface. Composition and Fabrication To prepare 10 specimens, a mixture of 54 grams of polymer and 20 ml of monomer was measured and used. Nanoparticles (procured from Reinste Nano Ventures Pvt. Ltd.) were incorporated into the monomer via ultrasonic dispersion [16]. The graphene nanoparticles were weighed and added to the monomer according to the specific requirements of each experimental subgroup. Ten specimens for each subgroup, with varying concentrations of graphene oxide (GO) and reduced graphene oxide (RGO), were then fabricated following the outlined procedure.The study involved three groups of specimens to evaluate the effect of graphene oxide (GO) and reduced graphene oxide (RGO) on the flexural strength of polymethylmethacrylate (PMMA). The Control group consisted of 10 specimens, each prepared by mixing 54 grams of polymer with 20 ml of monomer. Group A focused on incorporating GO into the PMMA matrix and was divided into three subgroups: A1 included 0.10 grams of GO combined with 53.90 grams of polymer mixed with 20 ml of monomer (10 specimens), A2 contained 0.20 grams of GO with 53.80 grams of polymer and 20 ml of monomer (10 specimens), and A3 had 0.30 grams of GO with 54 grams of polymer and 20 ml of monomer (10 specimens). Similarly, Group B explored the use of RGO and was also divided into three subgroups: B1 comprised 0.10 grams of RGO with 53.90 grams of polymer mixed with 20 ml of monomer (10 specimens), B2 contained 0.20 grams of RGO with 53.80 grams of polymer and 20 ml of monomer (10 specimens), and B3 included 0.30 grams of RGO with 54 grams of polymer mixed with 20 ml of monomer (10 specimens).Once the mixture reached the dough stage, the flasks were packed with PMMA, and a polythene sheet was placed over the mold space. The resin was subjected to trial closures in a hydraulic press until no flash was observed, ensuring an even flow of resin throughout the mold space. After processing, the flasks were cooled to room temperature with rapid cooling for 30 minutes followed by immersion in cool tap water for 15 minutes. The resulting strips were ground and polished to the required size. The 70 specimens were then stored in water at 37°C for 50 hours prior to flexural testing [5–6]. Flexural Strength Testing Specimens were mounted on a Universal Testing Machine (INSTRON) equipped for three-point loading. The load was applied at the center of the specimen with a crosshead speed of 1.50 mm/min and a span length of 40.00 mm. The maximum load before fracture was recorded. Flexural strength was calculated using the formula: S = 3FL /2bd2 Where: S = Stress, F = Load at break (N), L = Span of the specimen (65 mm), b = Width (10 mm), d = Thickness (3.3 mm) [2] Statistical Analysis Data were analyzed using SPSS 28.0 version. Descriptive statistics, including mean and standard deviation (SD), were calculated.Analysis of variance (ANOVA) was performed to assess significant differences in flexural strength among the groups, with a significance level of P < 0.0001. The Tukey-HSD test was used to determine the differences between groups, showing that the highest concentration of reduced graphene oxide exhibited the best improvement in flexural strength. Results The study demonstrates that incorporating graphene oxide (GO) and reduced graphene oxide (RGO) into polymethyl methacrylate (PMMA) significantly enhances flexural strength. Table 1 outlines the materials and methods, while Table 2 compares flexural strength and load among the control group and those with varying graphene concentrations. The control group exhibited the lowest strength, whereas both GO and RGO groups showed notable improvements. Specifically, Group B3 (0.30g RGO) achieved the highest mean flexural strength of 213.125 MPa, surpassing other groups including the GO groups, with Group A3 (0.30g GO) achieving 177.75 MPa. Table 3 provides the mean and standard deviation, showing that Group B3 had the highest mean strength and the lowest standard deviation. Graph 1 visually confirms these results. Table 4's ANOVA analysis shows a highly significant increase in strength with graphene incorporation, with a P-value less than 0.0001. Discussion Polymethylmethacrylate (PMMA) is a prevalent material in prosthodontics due to its ease of use and adaptability. [7] However, its inherent low flexural strength often results in fractures and failures in clinical applications. To address this issue, this study explored the potential of graphene nanoparticles to enhance PMMA’s mechanical properties.Graphene nanoparticles were chosen for their exceptional properties, including improved dispersion and bonding within polymer matrices. The study incorporated both graphene oxide (GO) and reduced graphene oxide (RGO) into the PMMA matrix via ultrasonic dispersion, aiming to achieve better uniformity and performance compared to other methods like ball milling. Results showed that both GO and RGO significantly improved PMMA’s flexural strength, with RGO providing the most substantial enhancement. The highest improvement was observed with a 0.30g concentration of RGO, which exhibited superior mechanical properties compared to GO.Furthermore, the study examined polymerization techniques, noting that microwave polymerization could potentially offer advantages over traditional water bath methods, such as reduced porosity and faster processing times. Effective polymerization relies on precise temperature control and the management of free radical release from benzoyl peroxide, crucial for avoiding defects like poor strength and uneven coloration.Visual assessments indicated that RGO caused minimal color changes, maintaining the aesthetic quality of PMMA, unlike GO, which resulted in more noticeable discoloration. Statistical analysis confirmed that RGO significantly boosted flexural strength, highlighting its effectiveness in improving PMMA’s performance.In conclusion, the incorporation of graphene nanoparticles, particularly RGO, markedly enhances the flexural strength of PMMA, making it a more robust material for prosthodontic applications. This advancement underscores the potential of nanotechnology to revolutionize dental materials, offering improvements in various applications within the field.The study's limitations include uneven nanoparticle distribution using ultrasonic dispersion, which could be improved with methods like ball milling. Future research should explore alternative graphene nanoparticle forms, such as nanotubes and nanorods, and consider microwave polymerization for more efficient processing.Future research should focus on several key areas to advance graphene nanoparticles in dental materials. Exploring various forms, such as nanotubes and nanorods, might offer better bonding and performance than graphene oxide (GO) and reduced graphene oxide (RGO). Optimizing incorporation techniques, like ball milling and chemical functionalization, may enhance nanoparticle dispersion and properties. Studies with higher nanoparticle concentrations should assess if they further improve flexural strength without compromising material quality. Long-term durability, wear, impact resistance, and aesthetic considerations like color change and translucency should be evaluated. Alternative polymerization methods, such as microwave polymerization, should be explored for efficiency. Biocompatibility and safety assessments are essential to ensure no adverse effects on oral tissues. Expanding research to other dental materials and analyzing the economic feasibility of commercial-scale production will be crucial for broader application and cost-effective use. Conclusion This study demonstrates that heat-cured PMMA reinforced with reduced graphene oxide (RGO) significantly improves flexural strength and maintains minimal color changes, making it a strong candidate for clinical use. Further research should investigate higher nanoparticle concentrations and alternative incorporation methods to optimize these benefits. Declarations Conflict of interest :Nil Acknowledgement : Nil Funding : Nil, Self financed Grants: Nil References Gurbaz O, Unalan F, Dikbas I. Composition of transverse strength of six acrylic denture resins. OHDMBSC 2010;9;1: 21‐4. Harini P, Mohamed K, Padmanabhan TV. Effect of Titanium dioxide nanoparticles on the flexural strength of polymethylmethacrylate: an in vitro study. Indian J Dent Res. 2014 Jul-Aug;25(4):459-63. doi: 10.4103/0970-9290.142531. PMID: 25307909. Han S, Sun J, He S, Tang M, Chai R. The application of graphene-based biomaterials in biomedicine. Am J Transl Res. 2019;11(6):3246. Dentistry Denture base polymer ISO 1567: 1999. Available from: http://www.iso.ch./iso/catalogue Detail Page. Catalogue Detail? CSNU MBER=20266andICSI=11andICSC=60andICS3=10 [Last accessed on 2008 Jul 29]. Zhang XY, Wu WL, Bian YM, Zhu BS, Yu WQ. The effect of different dispersive methods on flexural strength nano‐ZrO (2) reinforced denture polymethyl methacrylate. Shanghai Kou Qiang Yi Xue 2009;18:313‐6. Tuan Noraihan Azila Tuan Rahim, Dasmwati Mohamad, Abdul Rashin Ismail and Hazizan Md Akil. Incorporation of silica nanoparticles to increase the mechanical properties. J Phys Sci 2011;22:32‐105. Anusavice KJ, Phillips RW. Phillips’ science of dental materials. 11th ed. St. Louis, Mo.: Saunders; 2003. p. 147. Tables Tables are available in the Supplementary Files section. Tables 1-3 and Graph 1 and Table 4 Tables 1-3 and Graph 1 are available in the Supplementary Files section. Table 4 is not included with this version. Additional Declarations No competing interests reported. Supplementary Files TABLESANDGRAPHS.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-5007376\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":349940102,\"identity\":\"9154fc2a-e247-4f7d-b40c-a51932d9931f\",\"order_by\":0,\"name\":\"Divyabharathi Selvam\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIie2OsWoCQRRFn2yYNKvbziD6DQ8Wtkmxv7KDYBoLP2HTTBrF1s/QRrac8MA0K7YjWGgRKwMpI6yQUSxs3LUMOAfmwYV7uAPgcPxHyL5aqiE4hQQuN7lHEem5jHco+qKgPkeEij5A49OP+CFbx+Fy8TXZFAUEzz2EbXZbEeRHYpjv5My8RkYqBDHYI8j8toLEuryuKIkMY0amCGjsilTlijgqisPRnJmkQIirFW/etCu1CXStwuwKr1AEefTSykmOjVWkCn2e7/q6TGksP95W3xnFgf3Y6rdot4P3znR7KFEsT/w6+aejSwUA76ei4HA4HI/OHzWjWGYOCvraAAAAAElFTkSuQmCC\",\"orcid\":\"\",\"institution\":\"SRM Dental College, Bharathi Salai, Ramapuram\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Divyabharathi\",\"middleName\":\"\",\"lastName\":\"Selvam\",\"suffix\":\"\"},{\"id\":349940103,\"identity\":\"165e26f3-d2f0-40ac-be8b-7b75a14033f3\",\"order_by\":1,\"name\":\"Karthikeyan Vasudevan\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Karthikeyan\",\"middleName\":\"\",\"lastName\":\"Vasudevan\",\"suffix\":\"\"},{\"id\":349940104,\"identity\":\"3ed78995-fbf1-4cea-9a0e-ba02b627e016\",\"order_by\":2,\"name\":\"Noorul Rizwana\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Noorul\",\"middleName\":\"\",\"lastName\":\"Rizwana\",\"suffix\":\"\"},{\"id\":349940105,\"identity\":\"3121ebb8-6a93-432e-b516-4de79e4ed6ab\",\"order_by\":3,\"name\":\"Deepika Selvam\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"SRM Dental College, Bharathi Salai, Ramapuram\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Deepika\",\"middleName\":\"\",\"lastName\":\"Selvam\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2024-08-31 06:40:52\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-5007376/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-5007376/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":69796187,\"identity\":\"ededffcb-88b3-49d2-9fb4-3cf50de3d247\",\"added_by\":\"auto\",\"created_at\":\"2024-11-25 10:17:04\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":256618,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-5007376/v1/17f6ac22-fad3-42e9-87e4-404814870371.pdf\"},{\"id\":65948082,\"identity\":\"c1c0ecd4-b66e-48b0-9cd8-9661f3695a77\",\"added_by\":\"auto\",\"created_at\":\"2024-10-04 18:20:45\",\"extension\":\"pdf\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":212574,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"TABLESANDGRAPHS.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-5007376/v1/ec2b30b6ea29100e4f667cd5.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Enhancement of Flexural Strength in Polymethylmethacrylate (PMMA) Through the Incorporation of Graphene Nanoparticles: A Comparative In Vitro Study\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003e\\u0026nbsp;\\u003c/strong\\u003ePolymethylmethacrylate (PMMA) is one of the most widely used materials in dentistry, valued for its stability in the oral environment, ease of manipulation, polishability, and cost-effectiveness when used with standard equipment. [1] PMMA is extensively utilized in the fabrication of prostheses and orthodontic appliances. Since its introduction, there has been a continuous effort to enhance the mechanical properties of acrylic resins, particularly their flexural strength. The limited flexural strength of PMMA has been attributed to its brittle nature at its glass transition temperature of approximately 110\\u0026deg;C 3 and its susceptibility to cyclic loading. Fracture of the denture material remains the primary mode of clinical failure.Flexural strength, also known as the modulus of rupture, bend strength, or fracture strength, is a critical mechanical parameter for brittle materials. It refers to a material\\u0026rsquo;s ability to resist deformation under load. The transverse bending test is commonly employed, where a rod specimen with a circular or rectangular cross-section is bent until it fractures using a three-point flexural test technique. The flexural strength represents the highest stress the material experiences at its moment of rupture, measured in terms of stress (\\u0026sigma;).Numerous experiments have been conducted to improve the flexural strength and overall mechanical properties of PMMA. Reinforcing PMMA with materials such as glass fibres [6], sapphire whiskers, aramid fibres, carbon fibres, metal wires , nylon, polyurethane fibres and zirconia has led to significant improvements in its fracture resistance. Despite these advancements, there remains a need for further enhancement.Nanotechnology, a rapidly growing field, is poised to shape the future of science, medicine, and technology. The term \\u0026quot;nano\\u0026quot; is derived from the Greek word for \\u0026ldquo;dwarf,\\u0026rdquo; and nanotechnology involves the manipulation of matter at the scale of billionths of a meter, or nanometers\\u0026mdash;roughly the size of two or three atoms. Nanoparticles are increasingly used in material science for their wear resistance and anti-corrosion properties. The principle behind the use of nanoparticles in PMMA is that altering the filler size can enhance both the polishability and fracture resistance of the material. Among the various nanoparticles explored, graphene oxide (GO) has shown promise due to its unique properties.Graphene oxide, a derivative of graphene, is a two-dimensional, single-layer structure of sp2-hybridized carbon atoms arranged in a hexagonal configuration. It has been extensively studied for its potential to enhance the performance of materials, thanks to its exceptional physicochemical, optical, and mechanical properties. GO\\u0026apos;s outstanding mechanical properties, chemical stability, biocompatibility, and antibacterial effects contribute to reduced wear and friction. Despite being only a single atomic layer thick, GO is remarkably strong\\u0026mdash;200 times stronger than steel. Recent studies have highlighted that GO and graphene-based composites possess a range of beneficial characteristics, including a large surface area, excellent elasticity and ductility, good biocompatibility, and exceptional mechanical strength. [2,3] While research and development of graphene oxide-based dental biomaterials are still in their early stages, these materials\\u0026apos; distinctive properties and potential for functionalization with biomaterials suggest numerous unique clinical applications. However, this emerging field of nanotechnology requires further experimentation before it can be widely employed in clinical settings. Thus, this study was undertaken to evaluate whether incorporating graphene oxide into PMMA increases its flexural strength. Additionally, the study aims to compare the effects of different concentrations of graphene oxide and reduced graphene oxide on the flexural strength of PMMA.\\u003c/p\\u003e\\n\"},{\"header\":\"Materials and Methods\",\"content\":\"\\u003cdiv id=\\\"Sec2\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eMaterials\\u003c/h2\\u003e \\u003cp\\u003ePolymethylmethacrylate (PMMA) Resin, Graphene Nanoparticles, Dispersion Equipment, Polymerization Equipment, Mixing Tools, Molds, Precision Scales ,Mechanical Testing Equipment, these materials are essential for preparing and testing PMMA samples reinforced with graphene nanoparticles, and for conducting a comprehensive evaluation of their mechanical and aesthetic properties.\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eMethods\\u003c/h2\\u003e \\u003cdiv id=\\\"Sec4\\\" class=\\\"Section3\\\"\\u003e \\u003ch2\\u003eSample Preparation\\u003c/h2\\u003e \\u003cp\\u003eSeventy specimens, each with dimensions of 65 \\u0026times; 10 \\u0026times; 3 mm according to ISO 1567 standardization [4], were prepared from clear heat-polymerizing acrylic resin. Forty wax patterns of the specified dimensions were created and invested in flasks using the capping technique (2-pour technique) with dental plaster. Once the investing material had set, the flasks were dewaxed in a conventional water bath. After dewaxing, the flasks were opened, cleaned to remove any residual wax, and a separating medium (cold mold seal) was applied to protect the gypsum surface.\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec5\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eComposition and Fabrication\\u003c/h2\\u003e \\u003cp\\u003eTo prepare 10 specimens, a mixture of 54 grams of polymer and 20 ml of monomer was measured and used. Nanoparticles (procured from Reinste Nano Ventures Pvt. Ltd.) were incorporated into the monomer via ultrasonic dispersion [16]. The graphene nanoparticles were weighed and added to the monomer according to the specific requirements of each experimental subgroup. Ten specimens for each subgroup, with varying concentrations of graphene oxide (GO) and reduced graphene oxide (RGO), were then fabricated following the outlined procedure.The study involved three groups of specimens to evaluate the effect of graphene oxide (GO) and reduced graphene oxide (RGO) on the flexural strength of polymethylmethacrylate (PMMA). The Control group consisted of 10 specimens, each prepared by mixing 54 grams of polymer with 20 ml of monomer. Group A focused on incorporating GO into the PMMA matrix and was divided into three subgroups: A1 included 0.10 grams of GO combined with 53.90 grams of polymer mixed with 20 ml of monomer (10 specimens), A2 contained 0.20 grams of GO with 53.80 grams of polymer and 20 ml of monomer (10 specimens), and A3 had 0.30 grams of GO with 54 grams of polymer and 20 ml of monomer (10 specimens). Similarly, Group B explored the use of RGO and was also divided into three subgroups: B1 comprised 0.10 grams of RGO with 53.90 grams of polymer mixed with 20 ml of monomer (10 specimens), B2 contained 0.20 grams of RGO with 53.80 grams of polymer and 20 ml of monomer (10 specimens), and B3 included 0.30 grams of RGO with 54 grams of polymer mixed with 20 ml of monomer (10 specimens).Once the mixture reached the dough stage, the flasks were packed with PMMA, and a polythene sheet was placed over the mold space. The resin was subjected to trial closures in a hydraulic press until no flash was observed, ensuring an even flow of resin throughout the mold space. After processing, the flasks were cooled to room temperature with rapid cooling for 30 minutes followed by immersion in cool tap water for 15 minutes. The resulting strips were ground and polished to the required size. The 70 specimens were then stored in water at 37\\u0026deg;C for 50 hours prior to flexural testing [5\\u0026ndash;6].\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec6\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eFlexural Strength Testing\\u003c/h2\\u003e \\u003cp\\u003eSpecimens were mounted on a Universal Testing Machine (INSTRON) equipped for three-point loading. The load was applied at the center of the specimen with a crosshead speed of 1.50 mm/min and a span length of 40.00 mm. The maximum load before fracture was recorded. Flexural strength was calculated using the formula: S\\u0026thinsp;=\\u0026thinsp;3FL /2bd2 Where: S\\u0026thinsp;=\\u0026thinsp;Stress, F\\u0026thinsp;=\\u0026thinsp;Load at break (N), L\\u0026thinsp;=\\u0026thinsp;Span of the specimen (65 mm), b\\u0026thinsp;=\\u0026thinsp;Width (10 mm), d\\u0026thinsp;=\\u0026thinsp;Thickness (3.3 mm) [2]\\u003c/p\\u003e \\u003c/div\\u003e \\u003cdiv id=\\\"Sec7\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003eStatistical Analysis\\u003c/h2\\u003e \\u003cp\\u003eData were analyzed using SPSS 28.0 version. Descriptive statistics, including mean and standard deviation (SD), were calculated.Analysis of variance (ANOVA) was performed to assess significant differences in flexural strength among the groups, with a significance level of P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.0001. The Tukey-HSD test was used to determine the differences between groups, showing that the highest concentration of reduced graphene oxide exhibited the best improvement in flexural strength.\\u003c/p\\u003e \\u003c/div\\u003e\"},{\"header\":\"Results\",\"content\":\"\\u003cp\\u003eThe study demonstrates that incorporating graphene oxide (GO) and reduced graphene oxide (RGO) into polymethyl methacrylate (PMMA) significantly enhances flexural strength. Table\\u0026nbsp;1 outlines the materials and methods, while Table\\u0026nbsp;2 compares flexural strength and load among the control group and those with varying graphene concentrations. The control group exhibited the lowest strength, whereas both GO and RGO groups showed notable improvements. Specifically, Group B3 (0.30g RGO) achieved the highest mean flexural strength of 213.125 MPa, surpassing other groups including the GO groups, with Group A3 (0.30g GO) achieving 177.75 MPa. Table\\u0026nbsp;3 provides the mean and standard deviation, showing that Group B3 had the highest mean strength and the lowest standard deviation. Graph 1 visually confirms these results. Table\\u0026nbsp;4's ANOVA analysis shows a highly significant increase in strength with graphene incorporation, with a P-value less than 0.0001.\\u003c/p\\u003e\"},{\"header\":\"Discussion\",\"content\":\"\\u003cp\\u003ePolymethylmethacrylate (PMMA) is a prevalent material in prosthodontics due to its ease of use and adaptability. [7] However, its inherent low flexural strength often results in fractures and failures in clinical applications. To address this issue, this study explored the potential of graphene nanoparticles to enhance PMMA\\u0026rsquo;s mechanical properties.Graphene nanoparticles were chosen for their exceptional properties, including improved dispersion and bonding within polymer matrices. The study incorporated both graphene oxide (GO) and reduced graphene oxide (RGO) into the PMMA matrix via ultrasonic dispersion, aiming to achieve better uniformity and performance compared to other methods like ball milling. Results showed that both GO and RGO significantly improved PMMA\\u0026rsquo;s flexural strength, with RGO providing the most substantial enhancement. The highest improvement was observed with a 0.30g concentration of RGO, which exhibited superior mechanical properties compared to GO.Furthermore, the study examined polymerization techniques, noting that microwave polymerization could potentially offer advantages over traditional water bath methods, such as reduced porosity and faster processing times. Effective polymerization relies on precise temperature control and the management of free radical release from benzoyl peroxide, crucial for avoiding defects like poor strength and uneven coloration.Visual assessments indicated that RGO caused minimal color changes, maintaining the aesthetic quality of PMMA, unlike GO, which resulted in more noticeable discoloration. Statistical analysis confirmed that RGO significantly boosted flexural strength, highlighting its effectiveness in improving PMMA\\u0026rsquo;s performance.In conclusion, the incorporation of graphene nanoparticles, particularly RGO, markedly enhances the flexural strength of PMMA, making it a more robust material for prosthodontic applications. This advancement underscores the potential of nanotechnology to revolutionize dental materials, offering improvements in various applications within the field.The study's limitations include uneven nanoparticle distribution using ultrasonic dispersion, which could be improved with methods like ball milling. Future research should explore alternative graphene nanoparticle forms, such as nanotubes and nanorods, and consider microwave polymerization for more efficient processing.Future research should focus on several key areas to advance graphene nanoparticles in dental materials. Exploring various forms, such as nanotubes and nanorods, might offer better bonding and performance than graphene oxide (GO) and reduced graphene oxide (RGO). Optimizing incorporation techniques, like ball milling and chemical functionalization, may enhance nanoparticle dispersion and properties. Studies with higher nanoparticle concentrations should assess if they further improve flexural strength without compromising material quality. Long-term durability, wear, impact resistance, and aesthetic considerations like color change and translucency should be evaluated. Alternative polymerization methods, such as microwave polymerization, should be explored for efficiency. Biocompatibility and safety assessments are essential to ensure no adverse effects on oral tissues. Expanding research to other dental materials and analyzing the economic feasibility of commercial-scale production will be crucial for broader application and cost-effective use.\\u003c/p\\u003e\"},{\"header\":\"Conclusion\",\"content\":\"\\u003cp\\u003eThis study demonstrates that heat-cured PMMA reinforced with reduced graphene oxide (RGO) significantly improves flexural strength and maintains minimal color changes, making it a strong candidate for clinical use. Further research should investigate higher nanoparticle concentrations and alternative incorporation methods to optimize these benefits.\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003eConflict of interest :Nil\\u003c/p\\u003e\\n\\u003cp\\u003eAcknowledgement : Nil\\u003c/p\\u003e\\n\\u003cp\\u003eFunding : Nil, Self financed\\u003c/p\\u003e\\n\\u003cp\\u003eGrants: Nil\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n \\u003cli\\u003eGurbaz O, Unalan F, Dikbas I. Composition of transverse strength of six acrylic denture resins. OHDMBSC 2010;9;1: 21‐4. \\u003c/li\\u003e\\n \\u003cli\\u003eHarini P, Mohamed K, Padmanabhan TV. Effect of Titanium dioxide nanoparticles on the flexural strength of polymethylmethacrylate: an in vitro study. Indian J Dent Res. 2014 Jul-Aug;25(4):459-63. doi: 10.4103/0970-9290.142531. PMID: 25307909.\\u003c/li\\u003e\\n \\u003cli\\u003eHan S, Sun J, He S, Tang M, Chai R. The application of graphene-based biomaterials in biomedicine. Am J Transl Res. 2019;11(6):3246.\\u003c/li\\u003e\\n \\u003cli\\u003eDentistry Denture base polymer ISO 1567: 1999. Available from: http://www.iso.ch./iso/catalogue Detail Page. Catalogue Detail? CSNU MBER=20266andICSI=11andICSC=60andICS3=10 [Last accessed on 2008 Jul 29]. \\u003c/li\\u003e\\n \\u003cli\\u003eZhang XY, Wu WL, Bian YM, Zhu BS, Yu WQ. The effect of different dispersive methods on flexural strength nano‐ZrO (2) reinforced denture polymethyl methacrylate. Shanghai Kou Qiang Yi Xue 2009;18:313‐6. \\u003c/li\\u003e\\n \\u003cli\\u003eTuan Noraihan Azila Tuan Rahim, Dasmwati Mohamad, Abdul Rashin Ismail and Hazizan Md Akil. Incorporation of silica nanoparticles to increase the mechanical properties. J Phys Sci 2011;22:32‐105.\\u003c/li\\u003e\\n \\u003cli\\u003eAnusavice KJ, Phillips RW. Phillips\\u0026rsquo; science of dental materials. 11th ed. St. Louis, Mo.: Saunders; 2003. p. 147. \\u003c/li\\u003e\\n\\u003c/ol\\u003e\"},{\"header\":\"Tables\",\"content\":\"\\u003cp\\u003eTables are available in the Supplementary Files section.\\u003c/p\\u003e\"},{\"header\":\"Tables 1-3 and Graph 1 and Table 4\",\"content\":\"\\u003cp\\u003eTables 1-3 and Graph 1 are available in the Supplementary Files section. Table 4 is not included with this version.\\u003c/p\\u003e\\n\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Flexural strength, graphene oxide, reduced graphene oxide, nanotechnology, polymethylmethacrylate\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-5007376/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-5007376/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003e\\u003cb\\u003eBackground\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003ePolymethylmethacrylate (PMMA) is a common material in dental prosthetics, but its mechanical limitations, particularly in flexural strength, can affect its performance. Graphene nanoparticles, known for their exceptional mechanical properties, present a potential solution to enhance PMMA\\u0026rsquo;s strength.\\u003c/p\\u003e\\u003cp\\u003e\\u003cb\\u003eAim\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eThis study investigates the impact of incorporating graphene oxide (GO) and reduced graphene oxide (RGO) nanoparticles into PMMA on its flexural strength, comparing the effects of different nanoparticle concentrations.\\u003c/p\\u003e\\u003cp\\u003e\\u003cb\\u003eMaterials and Methods\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eSeventy heat-polymerized PMMA specimens (65 \\u0026times; 10 \\u0026times; 3 mm) were prepared following ISO 1567 standards. These specimens were divided into three groups: Control (no nanoparticles), Experimental Group A (GO), and Experimental Group B (RGO). Each experimental group was further subdivided based on the nanoparticle concentration: 0.10g, 0.20g, and 0.30g. Flexural strength was measured using a three-point bending test on a Universal Testing Machine with a crosshead speed of 1.50 mm/min and a span length of 40 mm. Data were analyzed using ANOVA and post-hoc Tukey-HSD tests.\\u003c/p\\u003e\\u003cp\\u003e\\u003cb\\u003eResults\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eThe control group recorded a mean flexural strength of 49.25 N. Incorporating GO and RGO nanoparticles significantly improved PMMA's flexural strength, with the highest strength observed in the RGO 0.30g group, showing a mean value of 213.6 N.\\u003c/p\\u003e\\u003cp\\u003e\\u003cb\\u003eConclusion\\u003c/b\\u003e\\u003c/p\\u003e \\u003cp\\u003eReinforcing PMMA with graphene nanoparticles, including GO and RGO at various concentrations, significantly enhances its flexural strength compared to unreinforced PMMA. These findings highlight the potential of graphene-based nanoparticles to improve the durability of dental materials, offering superior mechanical properties critical for long-term clinical use.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Enhancement of Flexural Strength in Polymethylmethacrylate (PMMA) Through the Incorporation of Graphene Nanoparticles: A Comparative In Vitro Study\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2024-10-04 18:20:40\",\"doi\":\"10.21203/rs.3.rs-5007376/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"74789402-ee95-4d64-a08c-bf6a9cf9b149\",\"owner\":[],\"postedDate\":\"October 4th, 2024\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2024-11-25T10:08:53+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2024-10-04 18:20:40\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-5007376\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-5007376\",\"identity\":\"rs-5007376\",\"version\":[\"v1\"]},\"buildId\":\"qtupq5eGEP_6zYnWcrvyt\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}