Objectives: To investigate corrosion resistance of NiTi orthodontic wires in artificial saliva and enamel remineralisation agents (MI Paste Plus, Elmex gelée, Mirafluor-k-gel) and determine whether improvement of the corrosion resistance can be achieved by rhodium (Rh NiTi) and nitride (NNiTi) surface coating on basic wires. Material and Methods: NiTi, RhNiTi and NNiTi wires were immersed in artificial saliva (pH 4.8, 5.1, 5.5, 6.6) for 28 days. Three specimen of every wire type were immersed to remineralisation agents once a week for five minutes, rinsed in distilled water and immersed to artificial saliva (pH 4.8). Ni and Ti ion release was determined by the use of mass spectrometry. Electrochemical testing was done on as-received wires and after immersion in artificial saliva (pH 4.8) and remineralisation agents. Results: Corrosion of NiTi wires relates to the type of coating and the concentration of hydrofluoric acid (HF) within the remineralisation agents. Power of prediction of nickel ion release influenced by HF concentration is considerable for uncoated (90%) and nitrified (88%) NiTi while moderate for rhodium coated NiTi (37%). Prediction models for titanium ion release influenced by HF concentration were significant for uncoated (64%) and nitrified NiTi (62%). Nickel ion release correlates with the pH of artificial saliva for uncoated NiTi (48%). Prediction models for titanium ion release influenced by the pH of the artificial saliva is considerable for rhodium coated (70%) and uncoated (58%) NiTi while moderate for nitrified NiTi (37%). Electrochemical testing showed differences in uncoated and nitrified NiTi, when compared to RhNiTi regarding corrosion current density, corrosion potential, breakdown potential and repassivation potential mainly in all tested media. Conclusion: Corrosion of NiTi wires without and with coating correlate with concentration of HF within enamel remineralisation agents. Commercially available coatings on NiTi orthodontic wires do not improve corrosion resistance. The localised (pitting) corrosion occurs because the coatings are porous.