Effect of Silver-Emitting Filler on Antimicrobial and Mechanical Properties of Soft Denture Lining Material

Abstract

Colonization of silicone-based soft lining materials by pathogenic yeast-type fungi is a common problem associated with the use of dentures. In this study, silver sodium hydrogen zirconium phosphate (SSHZP) was introduced into polydimethylsiloxane-based material as an antimicrobial filler at concentrations of 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, and 14% (w/w). The in vitro antimicrobial efficacy was investigated. Candida albicans was used as a characteristic representative of pathogenic oral microflora. Staphylococcus aureus and Escherichia coli were used as the typical Gram-positive and Gram-negative bacterial strains, respectively. The effect of filler addition on the Shore A hardness, tensile strength, tensile bond strength, sorption, and solubility was investigated. An increase in the filler concentration resulted in an increase in hardness, sorption, and solubility, and for the highest concentration, a decrease in bond strength. The favorable combination of antimicrobial efficacy with other properties was achieved at filler concentrations ranging from 2% to 10%. These composites exhibited mechanical properties similar to the material without the antimicrobial filler and enhanced in vitro antimicrobial efficiency.

Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler

“…In previous experiments, we tested SSHZP as an antimicrobial additive in two different dental materials: a PMMA denture base material [ 50 ] and silicone soft denture lining [ 51 ]. Both types of composites had shown enhanced antimicrobial properties, but for the PMMA-based materials, a significant deterioration of mechanical properties had been registered (results unpublished yet), while for polydimethylsiloxane-based composites, they were at the appropriate level [ 51 ]. In the presented work, we modified different materials in terms of the final application, polymerization, mechanical properties, and composition.…”

“…The in vitro reduction of bacteria was examined according to the previously described method [ 51 , 57 , 58 ] with some modifications. The standard strain of bacterium Streptococcus mutans ATCC 33535 was used.…”

“…So far, SSHZP has been reported as an additive into a polymethyl methacrylate (PMMA) denture base material [ 50 ] and a polydimethylsiloxane-based soft denture lining [ 51 ]. SSHZP was also previously investigated as an antimicrobial additive into chitosan and alginate fibers [ 52 , 53 ].…”

Effect of Antibacterial Silver-Releasing Filler on the Physicochemical Properties of Poly(Methyl Methacrylate) Denture Base Material

“…In the previously published part [37], the antimicrobial properties were confirmed via three-month in vitro experiments; thus, further tests were needed to investigate the other properties of the obtained composites related to their application. Additionally, S-P has also been investigated in our other works as an additive into silicone soft lining material [53] and direct restorative photopolymerizable resin-based composites [54], where only a slight influence of the filler on some physicochemical properties was noted. However, for the currently tested composites, the matrix and the method of introducing the filler into it were different which determined the inhomogeneous morphology of polymerized composites related with the used components (PMMA pre-polymerized particles) [37].…”

“…Chromatography techniques can be used to determine the release of compounds such as the residual monomer or dibenzoyl peroxide [121-123]. These investigations can be considered for selected composites together with analyses for other materials filled with S-P and based on different matrixes [53,54].…”