Effect Of Room Curing Polymethylmethacrylate Material Added Nano-Silver Base Inorganic Antibacterial Agent On Reproductive System Of Male Mice

Room temperature curing polymethyl methacrylate(PMMA) is widely used in clinical application due to its outstanding advantages,for example it is easy to process and mold, its operational requirement condition is low, and so on. But room temperature curing PMMA could accelerate pathogenic bacteria to adhere to its surface, because of its irregularity, hydrophilic property and its rough surface and porous internal structure caused by the residual methyl methacrylate releasing in saliva with its use in the mouth, leading to oral infectious diseases. It has been a research focus on making room temperature curing PMMA antibacterial for many years. Nano-silver base inorganic antibacterial agent has small size effect and quantum effect of nano-carrier, causing high surface activity and big specific surface area, increaseing its effective contact area with bacteria, and enhancing its antibacterial efficiency. Preliminary studies show, adding 2wt% nano-silver base inorganic antibacterial agent can not only makes room temperature curing PMMA antibacterial, but also does not change its mechanical property.It is a precondition for medical material applying to clinic to own good biosecurity. When being used in clinic, dental materials are immersed in saliva, their metabolite or degradation products may enter digestive system, and affect physical health. It is better for in vivo experiments to simulate the effect of biological materials on human. Male reproductive system is more sensitive to chemical substances than other systems. According to the researches, silver in silver-bearing materials can deposit in male reproductive system easily, and it is not easy to clear for body. What’s more, only low doses of silver has evident effect on male reproductive system. We have done many biological safety tests on room temperature curing PMMA adding nano-silver base inorganic antibacterial agent in the early,such as oral mucosa irritation test, hemolytic test, cytotoxicity test, micronucleus test, and so on.However, there are no studies about the effect of room temperature curing PMMA adding nano-silver base ingnorganic antibacterial agent on male reproductive system.In this study, artificial saliva extracts of antibacterial room curing PMMA are intragastric administration on male mice once a day for 35 days continuously, observe the mental and physical state of the mice,calculate the growth rate of body weight and testicular organ coefficient,and observe the pathological change. Take out semen from testes, take count of sperm, and calculate the percent of sperm abnormality rateand sperm vitality. In the developmental process of spermatogenic cells,spermatogonium in early period and primary spermatocyte in later period are the best sensitive period to chemical substances. In this study,artificial saliva extracts of antibacterial room curing PMMA are intragastric administration on male mice once a day for 5 days continuously,and at the 5th day and 14 th day spermatogonium sister chromatid exchange test and primary spermatocyte chromosome aberration test were undertaken respectively to evaluate the effect of room temperature curing PMMA adding nano-silver base inorganic antibacterial agent on the chromosome of spermatogonium and primary spermatocyte.The conclusions of this study are as follows:1 Artificial saliva extracts of antibacterial room curing PMMA are intragastric administration on male mice once a day for 35 days continuously. Toxic symptoms are not seen on male mice, changes about the growth rate of body weight and testicular organ coefficient are not seen either, testicular tissues are normal in pathology, and there are not obviously changes on the quality and quantity of mice, indicating that room temperature curing PMMA adding nano-silver base inorganic antibacterial agent has no harmful effect on body, testicular tissues and the quality and quantity of male mice.2 Artificial saliva extracts of room temperature curing PMMA adding nano-silver base inorganic antibacterial agent can not increase theSCE frequency in spermatogonium and chromosome aberration rate in primary spermatocyte, indicating room temperature curing PMMA adding nano-silver base inorganic antibacterial agent has no aberration inducing effects on spermatogonium and primary spermatocyte.