Preparation Of Three-dimensional Graphene And Modification Of Denture Base

Background:In the current clinical application,the main component of denture base is poly methyl methacrylate（PMMA）,which has many advantages,such as simple operation,high stability,good biocompatibility,low price,beautiful appearance,etc.But with the increase of clinical application,it also exposed some shortcomings,such as: poor mechanical properties,easy to crack and break;Lack of antibacterial properties,bacteria are easy to accumulate on the surface of denture base and cause denture stomatitis.Therefore,how to improve the mechanical properties and antibacterial properties of base materials has always been a hot topic in the field of oral materials.In recent years,most studies have mixed different materials into PMMA in the form of fillers to improve various properties of denture base.Therefore,this study is devoted to exploring a kind of biomaterial that can modify PMMA,which can improve the mechanical properties and antibacterial properties of the base material while conforming to biocompatibility,which has important clinical significance.Objective:In this experiment,three-dimensional Graphene（3DG）,a derivative of Graphene,was designed and prepared,and was added to PMMA with different mass ratios as fillers to study its effects on the biocompatibility,mechanical properties,hydrophilicity and antibacterial properties of PMMA denture base.Explore the most appropriate proportion to add.At the same time,the drug-loading performance of the prepared 3DG was studied to verify whether it had the ability to load and release drugs.The drug-loaded 3DG was re-added to PMMA as a filler to detect the changes in antibacterial performance of the modified PMMA denture base,providing a new direction for improving the performance of the denture base.Methods:1.Using graphene oxide（GO）as raw material,3DG was prepared by high temperature reduction method.2.The prepared 3DG was characterized by Scanning electron microscope（SEM）3.Six groups of specimens were prepared by adding 3DG to PMMA according to the mass percentages of 0%,0.5%,0.75%,1%,1.25% and 1.5%.4.CCK-8 method was used to evaluate the biocompatibility of each specimen.5.Use universal mechanical testing machine to explore the changes of mechanical properties of each specimen,including tensile strength,bending strength,bending modulus and compressive strength.6.Water contact Angle measuring instrument was used to explore the change of hydrophilicity of each specimen.7.Taking Candida albicans,the main pathogen of denture stomatitis,as an example,the antibacterial effect of each sample on Candida albicans biofilm was investigated by colony forming units（CFU）counting and MTT assay to detect bacterial metabolic activity.8.The antibacterial drug Amphotericin B（Am B）was studied as the target drug,and Am B@3DG was prepared,and the loading and releasing effects of the drug were analyzed.9.Taking the PMMA modification material commonly used in current studies-GO as the control,the drug loading and encapsulation rate of 3DG and GO were compared.10.By CFU counting,the antibacterial effects of PMMA,3DG-PMMA and Am B@3DG-PMMA on Candida albicans biofilms were compared.（The proportion of 3DG and Am B@3DG is 0.75%）Results:1.SEM results show that 3DG has been successfully prepared in this study.The prepared 3DG has high porosity and high specific surface area,and the pore diameter ranges from several nanometers to dozens of microns.2.The results of CCK-8 showed that the addition of 3DG did not inhibit cell proliferation,but promoted cell proliferation within a certain range.When the proportion of 3DG in the composite specimen was 0.75%,the effect of promoting cell proliferation was the best.3.The test results of mechanical properties show that with the increase of 3DG proportion in the specimen,the mechanical properties of the base materials show a trend of strengthening first and then weakening.When the proportion of 3DG is0.75%,the bending strength,bending modulus and tensile strength of the base materials are the best.When the addition ratio is 1%,the compression strength of the base material is the best.4.The results of the water contact Angle measuring instrument show that the water contact Angle of the base material decreases and the hydrophilicity increases with the increase of the proportion of 3DG in the specimen.5.The experimental results of CFU count and MTT showed that with the increase of the proportion of 3DG in the specimen,the antibacterial effect of the base material on Candida albicans was gradually enhanced.6.Related research results of drug loading performance show that the prepared3 DG has good loading and sustained-release capability.Compared with traditional GO,the drug loading capacity and encapsulation rate of 3DG are three times higher than that of 3DG.7.CFU counting results showed that Am B@3DG-PMMA had the best antibacterial effect on Candida albicans biofilms among PMMA,3DG-PMMA and Am B@3DG-PMMA.Conclusion:In conclusion,3DG,as a new PMMA modified filler,can improve the biosafety of the denture base,hydrophilic of the denture base,mechanical properties of the denture base,and antibacterial properties of the denture base,and the most appropriate addition ratio is 0.75%.At the same time,3DG is capable of loading and sustained-release drugs,and 3DG loaded as filler can further improve the antibacterial effect of base material on candida albicans biofilm,providing a new research idea for improving the performance of denture base.