Plazma nitrürleme yapılan soy olmayan metal alaşımlarına mikrobiyolojik tutunumun radyoizotop işaretleme yöntemi kullanılarak in vitro incelenmesi

Abstract

113 ABSTRACT Surface characteristics of dental restorative materials are an important factor which fosters the accumulation of dental plaque. The effect of surface roughness on bacterial adherence is complex. It's known that microdefects in the form of undulation and pitting were present even on polished surfaces. In the case of non- precious alloy, inaccuracies in casting and polishing technique may results in surface porosity and roughness. With the progressions in surface technology, the surface characteristics of the metals can be changed. Today, as a modern surface hardening technique, plasma nitriding process is used to enhance the surface properties of materials. Plasma nitriding is carried out in a nitrogen-hydrogen gas mixture at vacuum atmosphere. The outer layer formed on metal components by the inward diffusion of nitrogen consists of two layer compound and the diffusion layer. The aim of the present study was to determine the microbial adhesion to a non-precious alloy after plasma nitriding process by using 99mTc radiolabeled microorganisms. The plasma nitriding process was performed to the surfaces of metals prepared from a Ni-Cr alloy. The surface roughness and microhardness of the samples before and after plasma nitriding process were measured. The microorganisms were labeled with Technetium-99m (`Tc) and their radiolabeling yields were calculated. After the labeling procedure, metal discs were treated with a microorganism for each use. The amount of labeled microorganisms adhered on metal surfaces was determined with activity measurement by a Cd(Te) detector. The results of this study revealed that the amount of adherence of S.mutans, C.albicans and E.coli on surfaces of non-precious metal alloys changed by plasma114 nitriding process decreased substantially. Further in vivo studies concerning the plasma nitriding process on dental restorations made of metal alloys might be required.

113 ABSTRACT Surface characteristics of dental restorative materials are an important factor which fosters the accumulation of dental plaque. The effect of surface roughness on bacterial adherence is complex. It's known that microdefects in the form of undulation and pitting were present even on polished surfaces. In the case of non- precious alloy, inaccuracies in casting and polishing technique may results in surface porosity and roughness. With the progressions in surface technology, the surface characteristics of the metals can be changed. Today, as a modern surface hardening technique, plasma nitriding process is used to enhance the surface properties of materials. Plasma nitriding is carried out in a nitrogen-hydrogen gas mixture at vacuum atmosphere. The outer layer formed on metal components by the inward diffusion of nitrogen consists of two layer compound and the diffusion layer. The aim of the present study was to determine the microbial adhesion to a non-precious alloy after plasma nitriding process by using 99mTc radiolabeled microorganisms. The plasma nitriding process was performed to the surfaces of metals prepared from a Ni-Cr alloy. The surface roughness and microhardness of the samples before and after plasma nitriding process were measured. The microorganisms were labeled with Technetium-99m (`Tc) and their radiolabeling yields were calculated. After the labeling procedure, metal discs were treated with a microorganism for each use. The amount of labeled microorganisms adhered on metal surfaces was determined with activity measurement by a Cd(Te) detector. The results of this study revealed that the amount of adherence of S.mutans, C.albicans and E.coli on surfaces of non-precious metal alloys changed by plasma114 nitriding process decreased substantially. Further in vivo studies concerning the plasma nitriding process on dental restorations made of metal alloys might be required.