The aim of this study was to determine the dynamics of bacterial adhesion on alloys used in orthodontics. In the in vitro experiment bacteria Streptococcus mutans, Streptococcus oralis, Veillonella parvula and Aggregatibacter actinomycetemcomitans were incubated for the duration of four hours together with orthodontic wires made out of stainless steel and nickel-titanium alloys. The wires were then taken out and the bacteria were planted on a hard nutrient plate where the number of colonies per mL quantified. With the passing of time bacterial adhesion generally increased, but the growth differed between individual bacteria and individual alloy. Higher growth through hours was recorded in S.mutans and A.actinomycetemcomitans, while it was lower in V.parvula and S.oralis. S. oralis had a higher inital increase of adhesion on the NiTi alloy. S.oralis and V.parvula had higher adhesion to stainless steel and S.mutans to NiTi wires. A.actionomycetemcomitans had higher adhesion to stainless steel in the first two hours but in the third and fourth hour it was higher on NiTi. Lastly, V.parvula had the highest adhesion to both alloys throughout and S.mutans had the lowest. In conclusion, the adhesion of bacteria to alloys of orthodontic appliances depends on time, alloy and type of bacteria.