Study On The Effect Of Argon (Ar) And Tetrafluoromethane (CF4) Plasma Surface Modification Treatment On The Residual MMA、 Hydroscopicity And Solubility Of Room Curing Polymethylmethacrylate Material Added With Nano-silver Base Inorganic Antibacterial Ag

Room curing polymethylmethacrylate (PMMA) material has been frequentlyused in daily dental practice，as it is able to provide the essentially physical andchemical properties and the necessarily biological compatibility to be used in diversefunction. When the room curing PMMA material is applied to be the denture lines ofthe complete denture and the removable denture，it is in the oral environment for along time and can upset the oral micro ecological balance，at the same time，the roomcuring PMMA is porous，absorbent and irregularity，the pathogenic bacteria in oralcavity is mainly streptococcus mutans and candida albicans to colonize the surfaceadhesion and to lead to oral diseases such as dental caries and denture stomatitis.RHA-1nano-silver base inorganic antibacterial agent is added to denture basepolymer type Ⅱof Rijin "natural" series to make a new material. Our studies haveproved that the room curing PMMA material containing antibacterial agents haswonderful antimicrobial ability for streptococcus mutans and candida albicans，andantibacterial effect will last for a long time，meanwhile，the addition of the2wt%nano-silver base inorganic antibacterial agents will not affect the mechanicalproperty，however， the effect of the antibacterial agents on the content of residualMMA in room curing PMMA has not been investigated. Compared to the heat-curingPMMA material，the room curing PMMA material uses a chemical activator leadingto the low degree of polymerization reaction，the conversion of methyl methacrylate(MMA) into polymer is not complete and varying amounts of free or unreacted MMA remain in the polymerized material. Residual MMA affects the physical andmechanical properties，in addition，residual MMA may result in the irritant andallergic reaction. So studying the influnce of the addition of the2wt%nano-silverbase inorganic antibacterial agents for the residual MMA in the room curing PMMAis of great significance.Now the methods used to reduce the residual MMA of the room curing PMMAsuch as changing polymerization environment， microwave polymerization andpolymerization of water bath can reduce the residual MMA to some extent，but thesemethods are usually time-consuming, low efficiency and complicated to operate.Non-thermal Plasma（low temperature plasma）is a kind of non equilibrium Plasma，low temperature plasma technology is the emerging material modification researchfield in recent years. Being different from traditional surface modification，it is a dryprocess without dealing with the waste liquid and waste gas；modification occurs onlyin the surface layer；at the same time，it has a number of advantages such as shortaction time，high efficiency，simple process，convenient operation and less pollutionand so on. So it is often used in teeth whitening、sterilization、surface modification、coating treatment and thin film deposition in polymers. According to the lowtemperature plasma which is involved in the modified material surface chemicalreaction，the low temperature plasma surface modification can be divided into reactivelow temperature plasma surface modification treatment and non reactive lowtemperature plasma surface modification treatment. There has been the report aboutthe low temperature plasma technology to improve the wettability and cohesivenessof the room curing PMMA material，but there has not been the report about the lowtemperature plasma surface modification technology to affect the residual MMA inthe room curing PMMA material added he2wt%nano-silver base inorganicantibacterial agents. So the experiment is to study the change of the residual MMA、the release quantity of residual MMA、hydroscopicity and solubility of the roomcuring PMMA material after adding2wt%nano-silver base inorganic antibacterialagents，at the same time，the experiment uses different properties of low temperature plasma to deal with the room curing PMMA material with2wt%nano-silver baseinorganic antibacterial agents to study the change of the residual MMA、the releasequantity of residual MMA、hydroscopicity and solubility，aiming at initial preclinicalevaluation of the new material，in order to provide basis for clinical application.The experiment adds the RHA-1nano-silver base inorganic antibacterial agentto room curing PMMA material，using Ball milling method to make them fullymixing in order to make the experiment required room curing PMMA materialcontaining2wt%nano-silver base inorganic antibacterial agents. In accordance withthe pharmaceutical industry standard of the People，s Republic of China（YY0270-2003）， the experiment detects the residual MMA、the release quantityof residual MMA、hydroscopicity and solubility of the room curing PMMA materialwithout nano-silver base inorganic antibacterial agents and the antibacterial roomcuring PMMA material with2wt%nano-silver base inorganic antibacterial agents.The experiment respectively uses argon（Ar） and carbon tetrafluoride（CF4） lowtemperature plasma surface modification processing the antibacterial room curingPMMA material. And detect the residual MMA、the release quantity of residualMMA、hydroscopicity and solubility of the antibacterial room curing PMMA material.By X-ray photoelectron spectroscopy，the experiment studies the change of thesurface structure of the antibacterial room curing PMMA material after lowtemperature plasma surface modification to research the mechanism of lowtemperature plasma surface modification.This experiment draws the following conclusions through the above test：1Adding2wt%nano-silver base inorganic antibacterial agents does not affectthe residual MMA、the amount of the released residual MMA、hydroscopicity andsolubility of room curing PMMA material.2A dense crosslinking layer forms on the surface of the antibacterial roomcuring PMMA material after Ar and CF4low temperature plasma surfacemodification，and CF4low temperature plasma surface modification can bring in thefluoride group on the surface to increase hydrophobicity of the material. 3Ar and CF4low temperature plasma surface modification can effectivelyreduce the residual MMA、the release quantity of residual MMA and hydroscopicityof the antibacterial room curing PMMA material， however Ar and CF4lowtemperature plasma surface modification have no significant effect on the solubility ofthe antibacterial room curing PMMA material.