Abstract: Objective To investigate the effect of 2% nano-silver base inorganic antibacterial agent on concentration of  residual methylmethacrylate (MMA) of room temperature curing polymethylmethacrylate(PMMA) material and to observe  the concentration changes of the residual MMA  after treated with  low temperature plasma argon (Ar) and tetrafluoromethane (CF4).Methods 2% nano-silver base inorganic antibacterial agent was added into the room temperature curing PMMA material through ball milling method to make specimen. Both antibacterial room temperature curing PMMA material group(antibacterial group) and conventional room temperature curing PMMA group(control group) were treated with Ar and CF4 plasma surface modification and surface bombardment processing. And then acetone and chloroform were used to extract the residual MMA of the specimens before and after treatment  and residual MMA released from the specimens into artificial saliva,separately. Gas chromatography(GC) method was used to determine the concentrations of residual MMA in tiye pumping and extract.Results Compared with control group,the addition of 2% nano-silver base inorganic antibacterial agent did not show statistical significance for the residual MMAconcentration in PMMA material in antibacterial group had no significant difference(P>0.05). There were siginficant differences of the concentration and release amount of MMA in the materials after treated with  low temperature plasma,and the concentration of the residual MMA in the materials  obtained in control group  after  treatment of CF4 plasma bombardment was the lowest.The content of MMA in the artificial saliva was also quite different   in the second day compared with the first day(P<0.05).  After 2 d,with the prolongation of   time,the amount of MMA released from polymers tended to be stable. In  antibacterial group,when the specimens were treated with  CF4 plasma surface bombardment and surface modification,the maximum amounts of MMA appeared in the second day and the fourth day,which were higher than those of the other time points,respectively(P<0.05).Conclusion The addition of  2% nano-silver base inorganic antibacterial agent will not affect the  residual amount of MMA in the PMMA material obviously. Low temperature plasma treatment technique can effectively reduce the amount of residual MMA and its emission in room temperature curing PMMA material.

Key words: low temperature plasma, nano-silver base inorganic antibacterial agent, room temperature curing, polymethylmethacrylate, residual methylmethacrylate