Study On The Influence Of Nano-Silver Base Inorganic Antibacterial Agents On Antibacterial And Mechanical Property Of Room Curing Polymethylmethacrylate Material

As one of the restorative materials, polymethylmethacrylate material is widely used in daily dentistry. According to the curing method, the PMMA may be divided into heating-curing, room-curing and photo-curing three types. Because its physical and chemical performance and the biological compatibility are good, it is still used until today as the denture base material.Denture base material can cause oral diseases such as dental caries and denture stomatitis if its Long-standing exist in oral cavity environment,but traditional disinfection methods such as the mechanical cleaning, dip in chemicals or drug controlled release system have many deficiencies and unable to satisfy the clinical request. With nanotechnology's rapid development, antibiotics development also has made very big breakthrough in recent years. Nano - silver base inorganic antibacterial agents unify the unique nanometer granule light-sized effect and the quantum effect, as well as the borad antibacterial spectrum , safty, the persistent antibacterial effect and its superiority have received the approval. It has become a research focus to join it into the restorative material to develop one new antibacterial biological materials that achieve both the broad spectrum persistent antibacterial effect and remain its mechanical property. Some researchers had succeeded in joining it into the composite resin, such as the artificial denture soft lining material, the alginate impression material, the heating-curing denture base resin and so on. They confirmed that the antibacterial compound materials have the good antibacterial effect to the oral cavity common pathogenic bacteria and the right amount addition has not had the obvious influence to its mechanical property.But until now there still have no report on the influence of increasing nano - silver base inorganic antibacterial agents in the room curing PMMA material on its chemical and physical properties. this experiment will open new domain on the room curing PMMA material antibacterial modification and provide theoretical basis for clinical application.In this experiment,how does antibiotics disperse in the room-curing PMMA material is a technical difficulty. Some scholars confirmed that the ball grinding law is an effective method that made antibiotics disperses evenly in the compound materials. Therefore this experiment uses the ball grinding legal system preparing antibacterial parent material technology to join the nano - silver base inorganic antibacterial agents in the room- curing PMMA powder body to make parent materials including 10% antibiotics. Then dilutes it into six densities including antibiotics respectively is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%. Finally, confirm the feasibility of this method through the naked eye and the scanning electron microscope .Streptococcus mutans and Candida albicans are the main pathogenic bacterias of dental caries and denture stomatitis. Therefore this experiment appraised the antibacterial effect through examine antibacterial rate of the testpiece including nano - silver base inorganic antibacterial agents to the Streptococcus mutans and Candida albicans in vitro. The denture base material in the oral cavity receives the compound strength. The bending strength, the shock strength as well as the attrition experiment may effective response the change of this strength. Therefore this experiment carry on the above three mechanics test to the testpiece containing different density antibiotics antibacterial to appraise the change of its mechanical property.This experiment draws the following conclusion through the above test:1 Through the naked eye and the scanning electron microscope's observed result,we can see that the nano - silver base inorganic antibacterial agents disperse evenly in the room curing PMMA material, has achieved the anticipated effect. Thus proved the feasibility that use the ball grinding legal system to prepare the antibacterial parent material technology.2 The antibacterial base resin carring the nano - silver base inorganic antibacterial agents has demonstrated the strong antibacterial effect in vitro to Streptococcus mutans and Candida albicans.When antibiotics content achieves 1% ,its antibacterial rate to the Candida albicans already surpassed 90%, antibacterial rate to the Streptococcus mutans surpasses 50%,while When antibiotics content achieves 2.5%, its antibacterial rate to the Streptococcus mutans surpasses 90%, antibacterial rate to the Candida albicans already achieved 100%. Therefore applies it in the oral cavity will be able to effectively suppress the occurrence of denture stomatitis and dental caries. From antibacterial angle embarking, when clinical practice suggested that the increase compares between 2.5%~3.0%. 3 Few nano - silver base inorganic antibacterial agents adding in the room-curing PMMA material affect not obviously to its mechanical property. But when antibiotics content surpasses 2.5%, the above three mechanical properties have the significance change. Therefore from mechanical property angle embarking, when clinical practice suggested that the increase proportion is not higher than 2.5%.4 When room-curing PMMA material is used to reline the complete denture, suggest that antibacterial agents's increase compares between 1%~2% ; when room-curing PMMA material is used to reline the removable partial denture and active appliances , suggest that antibacterial agents's increase compares between 2.5%~3%.