Preparation And Application Of PMMA Denture Base Materials With Negative Ion Powder

Objective:To prepare the denture base resin with negative ion powder and evaluate the effect of properties of denture base resin with different contents of negative ion powder for clinical application.Materials and methods:The negative ion powder was grinded (0h,4h,8h,12h,16h,22h) through the ultrasonic dispersion, ball milling and high-speed mixing process. Its crystal pattern, particle size and surface morphology were characterized by X Ray Diffraction (XRD),dynamic laser scattering instrument and scanning electron microscope (SEM).The number of negative ion in different grinding time was tested by 3010-pro negative ion tester. Ultrafine negative ion powder was treated with GMA,which structure was characterized by scanning electron microscope (SEM),FT-IR spectroscopy (FT-IR) and Thermal Gravity Analysis(TGA). Denture base material with negative ion powder was prepared by in-situ polymerization method, which was tested and characterized on the mechanical properties, tribological properties, antibacterial properties.Result and conclusion:1.With the milling time (0 h,4 h,8 h,12 h,16 h,22 h) increasing, particle size of negative ion powder was gradually decreased. The particle size was 232nm after 22h. XRD showed the crystal pattern of negative ions powder could not be changed by the ball mill and the number of negative ions number could not be significantly changed too. Therefore, optimum utilization of the ultrasonic dispersion, ball milling and high-speed mixing technologies is necessary to most efficiently achieve stable dispersions with the target particle size characteristics. FT-IR showed the 1460.8cm-1 the characteristic peak of C= C, which proved that the GMA was successfully bonded in the negative ion powder surface. TGA:The mass loss of treatment group was obviously lower than that of untreated group about 17%. SEM showed the treatment group was internal size uniform, uniform dispersion, however, the untreated group appeared reunion phenomenon and particle was larger.2. With the content of negative ion powder (0%wt,1%wt,2% wt, 3% wt,4% wt,5% wt) increasing, the mechanics properties of the treated group decreased except for the first increased. When the content of negative ion powder was 2% wt, comprehensive performance achieved optimal performance about mechanical performance. Under the condition of dry friction, the rate of volume wear was reducing with the content of negative ion powder (0% wt,2% wt,5% wt) increasing. Compared the untreated group, friction coefficient was not obviously changed. Under lubrication of artificial saliva, the rate of volume wear was lower and friction coefficient was not obviously changed too. The SEM showed that under the condition of dry grinding, furrows and crack on the surface of the samples was less compared to the treatment group. And grinding crack on the surface of the sample was relatively smooth under the condition of lubrication of artificial saliva.3. The antibacterial rates of treatment group rised about staphylococcus aureus and escherichia coli with the content of negative ion powder (0% wt,1% wt,2% wt,3% wt,4% wt, 5% wt) increasing. The bacteriostatic rate reached 98.2%,99.1%, respectively,when the content of negative ions powder was 5% wt.