Titanium is used in many fields in addition to being used in dental implants. As the use of titanium increases, concerns over safety are increasing as well. In recent years, studies with regard to titanium toxicity have been on the rise. Although they have mainly been focused on environmental and basic fields, studies are now expanding into the medical field. Thus, there is a need for interest with regard to titanium safety and dangers in the field of dentistry. Titanium dental implants can cause corrosion and wear. Particles and ions of titanium and titanium alloy components due to corrosion and wear can be deposited in surrounding tissues, and inflammation reactions can occur. The accumulation of titanium ions and particles can occur systemically as well as in the surrounding tissues, which can lead to toxic reactions in other tissues including yellow nail syndrome. Additionally, there are cases where the metal material is hypersensitive. Currently, zirconia implants are considered to be an alternative; however, there are still limitations due to a lack of long-term clinical data. Within the limitation of this study, it was suggested that we should be aware of the rare problems of titanium toxicity.