The Effect Of Adding Nano-Silvered Zirconium Phosphate On Mechanical And Chronergy Of Denture Base Resin

Objective:To explore the effects of nano-silver-loaded zirconium phosphate which was added to polymethyl methacrylate(PMMA)with different proportion on the mechanical properties of PMMA denture base and the changes of mechanical properties of those materials after accelerated aging with artificial saliva immersion.This study intend to provide some guidance for the selection of removable partial denture to repair dentition defect and edentulous.Methods:Nano inorganic Ag-loaded zirconium phosphate(Conval PAg-40,Ag content 3%)was added to the resin base with 0%,1%,3%,5%and 7%mass percentage.According to the International Standard Orgernization(ISO),The surface hardness,flexural strength,compressive strength,tensile strength,water absorption value and dissolution value are totaled in 6 indicators,5 sets of different specifications of the test pieces,each set of different specifications is prepared for10 test pieces,total 250 test pieces,and 5 test pieces are randomly selected from the10 test pieces and divided into Group A,and the remaining 5 test pieces are Group B.Group B are immersed in artificial saliva and treated in a water bath at 57?for 14days,but Group A are not.According to the ISO,The surface hardness of all the samples in Group A and Group B,was tested by Rockwell Hardness Tester,the flexural strength,compressive strength and tensile strength were tested by Electronic Universal Tester.and the water absorption value and dissolution value are calculated by weighing the difference between the masses before and after soaking of each test piece by using Electronic Balance.Finally,we make a statistical analysis of all data.Results:(1)Surface hardness:The Rockwell hardness of PMMA specimens in Group A increased with the increase of the proportion of nano-silver-loaded zirconium phosphate(p<0.01).After 14 days of accelerated aging in artificial saliva,the Rockwell hardness value of Group B specimens with the same proportion was lower than that of Group A specimens,but there was no statistical difference between them(p>0.05).(2)Flexural strength,Compressive strength and Tensile strength:The flexural strength,compressive strength and tensile strength of PMMA specimens with different proportion of nano-silver-loaded zirconium phosphate in group A were significantly different(p<0.01).,With the increase of the proportion of nano-silver-loaded zirconium phosphate,the flexural strength,compressive strength and tensile strength increased from 0%to 3%and reached the highest value gradually,then gradually declined.After 14 days of accelerated aging in artificial saliva,the flexural strength,compressive strength and tensile strength of the aged specimens in Group B decreased compared with Group A when the addition ratio of nano-silver-loaded zirconium phosphate are same,but there was no significant statistical difference between the two groups(p>0.05).(3)Water absorption and Solubility value:Water absorption value and solubility value:There were statistical differences in water absorption value and solubility value of PMMA specimens added with different proportion of nano-silver-loaded phosphoric acid in group A(p<0.01).The water absorption and solubility values of the sample increase with the addition ratio of nano-loaded silver zirconium phosphate.From the addition ratio of 0%to the addition ratio of 3%to t he lowest value and then gradually increase;after 14 days of artificial saliva immersion aging,the water absorption value of the Group B of the same addition ratio is lower than that of the unaged Group A specimen.The solubility value was higher than that of the unaged Group A,but there was no statistical difference between them(p>0.05);the water absorption of Group A was 17.57~27.01?g/mm~3,and Group B was 19.36~30.38?g/mm~3,The solubility value of Group A was 2.04~2.93?g/mm~3,Group B was2.16~3.21?g/mm~3.all of them met the clinical requirements of denture base materials.Conclusion:(1)Adding nano-silver-loaded zirconium phosphate can improve the mechanical properties of PMMA,the comprehensive physical and mechanical properties of PMMA are best when the addition ratio is 3%;(2)The accelerated aging of artificial saliva has no significant effect on the mechanical properties of PMMA materials with nano-silver-loaded zirconium phosphate.