Titanium and its alloys are increasingly important in dentistry. Thin titanium nitride (TiN) coatings improve properties of metallic material for industrial purposes. Recently TiN coatings have been advocated in dentistry. In a survey of the literature, aspects of biological, mechanical and corrosive behaviour are assessed. Moreover, specific problems for clinical application are indicated. It is concluded that as long as the integrity of the TiN coating is not guaranteed under critical conditions, one should be cautious with its clinical application, and in no situation can it be used to improve deficient dental alloys.