Preliminary Evaluation Of Biological Safety Of Room Curing Potymethyf Methacrylate Material Added With An Nano-inorsjanic Anitbacterial Agents Loaded Silver

The research about norganic antibacterial agents began in the1960s. It isreported that it can effectively suppress common oral pathogens. Most scholars arefocusing on studying about heat-curing denture base material used to make permanentdenture，seldom about the room temperature curing polymethyl methacrylate (PMMA)material. RHA-1nano-silver base inorganic antibacterial agent is added to denturebase polymer type Ⅱof Rijin "natural" series to make a new material. Our studieshave proved that the room temperature curing PMMA material added withantibacterial agents have wonderful antimicrobial ability of oral common pathogens,and antibacterial effect will last for a long time. After a series of experiments in ourpre-research, the antibacterial properties and mechanical properties of such materialscan meet the clinical requirements. But its biological safety has not been known yet.First of all,room temperature curing PMMA materials add with Nanosilver-basedantimicrobial agent fully and uniformly mixed. Our Group wants to mix them by Ballmilling method, Water bath oscillation method trituration. My experiment is to makean evaluation about these mechanical mixing methods through observing differentcolors by eyes and the distribution of silver particles under the SEM. According to theresults, we will select the best method for making the specimens for follow-upexperiments.Biological safety principles are to eliminate destructive biological materials ofhuman organs, such as cell toxicity and carcinogenicity. For new materials,bio-security is essential indicator of clinical application. Hemolysis test is to evaluatewhether the material bring about acute hemolytic reaction in vitro, and initially toclear whether the material would cause harm to humans. Room temperature curing PMMA material is mainly used for reline of complete denture and partial dentures,and for orthodontic appliance. It will contact with the patient’s oral mucosa directly,and if mucosal ulceration and other special circumstances take place，the materialwith hemolytic reaction to body will produce some injury which is systemic,therefore Hemolysis Test is necessary. Mucosal irritation test is used to evaluatedental materials for temporary or long-term contacting with the oral tissuesstimulating effect on the oral mucosa. The room temperature curable PMMA materialwith mucosal contact is long-term and direct. If the new material of the antibacterialagent has irritation of the mucous membranes, and will seriously affect the patient’stissue health. Therefore Mucous Membrane Irritation Test is feasible. In summary, Iselect the two tests first, and it is the preliminary evaluation of biological safety ofroom temperature curing PMMA material added nano-Silver agent.It is clear that ball milling method is the best way, because it has superiority fromthe results observed either only by eye or by electron microscopy, and it is thefeasibility of using ball milling method to mixed the material. The final choice ismilling method to make the subsequent test specimen. Hemolysis Test detected roomtemperature curing PMMA material add a ratio of2.0wt%, measured hemolysis rateof2.45%, in line with national standards, not to produce hemolytic reaction to body.Mucosal Irritation Test of room temperature curing PMMA material at a concentrationof0to2.5wt%of the oral mucosa were not irritating. Based on the results of thesetwo experiments, it has good biosafety preliminary evaluation of such material.