Titanium is used for many dental applications and instruments, such as orthodontic wires, endodontic files, dental implants, and cast restorations. The popularity of titanium is primarily due to its good mechanical properties, its high corrosion resistance, and its excellent biocompatibility. A thorough review of the medical and dental literature reveals, however, that titanium can also cause chemical-biological interactions. Tissue discoloration and allergic reactions in patients who have come in contact with titanium have been reported. The biostability of titanium is becoming increasingly questioned. At the same time, new technologies and materials, such as high-performance ceramics, are emerging which could replace titanium in dentistry in the not-too-distant future. Schlagwörter: allergies, α-case layer, biocompatibility, composition, corrosion, nonalloyed titanium