MICROBIAL PROPERTIES OF TITANIUM AND ITS ALLOYS FOR ORAL BACTERIUM STREPTOCOCCUS-MUTANS

The purpose of this study was to estimate the microbial properties of titanium and its alloys from two viewpoints: bacterial adhesion and an tibacterial effect in vitro. The adhesion of oral bacterium, Streptoco ccus mutans (S. mutans) MT8148, on Ti, Ti-6Al-4V, and Ti-56Ni surfaces , was investigated by the scintillation counting of radioactivity of b acteria labelled with radio isotope. On the other hand, the influences of the materials on bacterial growth were determined by the optical d ensity of bacterial suspensions. The numbers of bacteria adhered to Ti , Ti-6Al-4V, and Ti-56Ni were larger than that to glass and no differe nces among the materials at 7.2 ks (2 h). The number of adherent bacte ria to the materials at 86.4 ks (24 h) was larger in Ti than in Ti-56N i. No difference in relative growth of the bacteria among the material s was observed.