The aim of this study was to explore the resistance to general and pitting corrosion of stainless steel and titanium-based orthodontic mini implants in an oral environment. Studies were performed in artificial saliva and in the presence of two oral hygiene products (one containing chlorhexidine digluconate with sodium fluoride and another containing probiotic bacteria) that are usually recommended to orthodontic patients. The results showed that mini implants made from stainless steel have lower resistance to corrosion than titanium implants. General corrosion was increased in both steel and titanium implants when antiseptic agents containing fluoride ions were used, while the tendency towards pitting corrosion was not noticeably altered. Probiotics, on the other hand, had a beneficial effect on general corrosion resistance but were associated with an increased tendency towards pitting corrosion for both implant materials.