Bacterial viability and physical properties of antibacterially modified experimental dental resin composites

Abstract

Purpose: To investigate the antibacterial effect and the effect on the material properties of a novel delivery system with Irgasan as active agent and methacrylated polymerizable Irgasan when added to experimental dental resin composites.

Materials and methods: A delivery system based on novel polymeric hollow beads, loaded with Irgasan and methacrylated polymerizable Irgasan as active agents were used to manufacture three commonly formulated experimental resin composites. The non-modified resin was used as standard (ST). Material A contained the delivery system providing 4 % (m/m) Irgasan, material B contained 4 % (m/m) methacrylated Irgasan and material C 8 % (m/m) methacrylated Irgasan. Flexural strength (FS), flexural modulus (FM), water sorption (WS), solubility (SL), surface roughness Ra, polymerization shrinkage, contact angle Θ, total surface free energy γS and its apolar γS (LW), polar γS (AB), Lewis acid γS (+)and base γS (-) term as well as bacterial viability were determined. Significance was p < 0.05.

Results: The materials A to C were not unacceptably influenced by the modifications and achieved the minimum values for FS, WS and SL as requested by EN ISO 4049 and did not differ from ST what was also found for Ra. Only A had lower FM than ST. Θ of A and C was higher and γS (AB) of A and B was lower than of ST. Materials A to C had higher γS (+) than ST. The antibacterial effect of materials A to C was significantly increased when compared with ST meaning that significantly less vital cells were found.

Conclusion: Dental resin composites with small quantities of a novel antibacterially doped delivery system or with an antibacterial monomer provided acceptable physical properties and good antibacterial effectiveness. The sorption material being part of the delivery system can be used as a vehicle for any other active agent.

Figure 1. Poly-Pore hollow bead sorption material, unloaded (magnification 500 x).

Figure 2. Chemical formula of Methacryl-Irga.

Figure 3. Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with A. viscosus on material ST after 24h.

Figure 4. Superimposed fluorescence microscopic image (magnification 400 fold) of vital (green) and non-vital (red) colonization with A. viscosus on material A after 24h.