Effect of silver nitrate incorporation into heat polymerized acrylic resin on some mechanical properties

Abstract

Background: Polymers are very rarely used in their form. These modifications are carried out in order to improve theproperties of polymers.Recently silver have been used successfully as antimicrobial (medical and dental)biomaterials that can prevent caries and infection of implants. The aim of the present in vitro study is to evaluate theeffect of addition of silver nitrate to acrylic resin in different concentrationsthrough several tests part of these are: Theeffect of this additive on impact strength, transverse strength, and tensile strength of AgNO3 – loaded resin, and toassess any effect of addition of silver nitrate on coloration of acrylic resin.Materials and methods: Different concentrations of silver nitrate (9.375, 15, 30, 60, 120, 150, 300, 600 and 900 ppm)were prepared from stock solution of 1000 ppm silver nitrate. The specimens were prepared in accordance with themanufacturer's instructions and the tested silver nitrate solution was added to the acrylic resin powder and monomerin a fixed volume (0.2ml). Controls devoid of silver nitrate were included.Results: Fourier transform infra-red confirmed that there was no chemical bond between the Poly methylmethacrylate and silver nitrate. There was insignificant increasing (P=0.05) in impact strength observed whencompared with control group. In transverse strength test, significant reduction was show (P<0.001). While for tensilestrength there was insignificant reduction with 9.375(P=0.05NS) and 15(P=0.42NS) ppm silver nitrate. However, it wassignificant above 15 ppm (P<0.001). Darkening of silver nitrate -loaded resins were shown to be started withconcentration of silver nitrateof 300 ppm and above.Conclusions: The additions of silver nitrate to acrylic resins yield good color stability and mechanical properties,depending on the concentration of silver nitrate