engleski

Probiotic bacteria Lactobacilus reuteri Prodentis can induce corrosion degradation of the surface of NiTi alloy above the influence of saliva

Aim: The aim was to determine if the probiotic bacteria have additional effect above the influence of saliva on the surface on two principle alloys used in orthodontics and if this influence is modified by the coating of the alloy. Methods: Research was conducted on four types of archwires with dimensions 0.508 × 0.508 mm – three NiTi alloys (composition w(Ni) = 50.4 % ; w(Ti) = 49.6 %) with uncoated surfaces, rhodium and titanium nitride coated, as well as stainless steel (SS). They were exposed for a period of 28 days to pure artificial saliva (pH = 4.8), as well as saliva with the addition of probiotic bacteria Lactobacilus reuteri Prodentis. Unexposed archwires were used as control. The surface roughness was quantitatively studied using atomic force microscopy. Raman spectroscopy was used to identify metal oxides formed on the surface of alloys. Results: Experiments demonstrated that probiotic bacteria affect the surface and their effect is dependent on the type of alloy and coating. They increase surface roughness in the case of uncoated NiTi above the influence of saliva (p<0.05). Probiotic bacteria tend to decrease corrosive influence of saliva on SS and also in NiTi when the alloy is coated with rhodium or titanium nitride. Raman spectroscopy has confirmed that only SS samples are prone to oxidation processes, majorly favoured upon exposure to saliva than probiotic bacteria. Conclusion: Probiotic bacteria induce degradation of the surface of NiTi alloy above the influence of saliva, but only if the surface is not coated. It does not produce additional roughness on SS above the influence of saliva.

probiotic bacteria ; nickel-titanium alloy ; steel ; corrosion ; surface

Financirano projektom Hrvatske zaklade za znanost 7500