Talon cusp, or the „talon-like small bump“, is a rare anomaly in the shape of tooth crown,which affected frontal teeth in maxilla and mandible. There is a superfluous smallbump, most frequently on the oral surface of the tooth,which extends from the cement-enamel junction in direction to the incisor edge. The authors followed the occurrence and complications of this anomaly in patients treated by orthodontics. There were 698 patients under treatment, who were admitted to orthodontic treatment during 1998–2003. Talon cusp was noted in four patients prevalence was 0.57%. In three cases the permanent lateral incisor was affected, in one case it was the upper permanent middle incisor. In the first case the talon cusp was the place of premature contact and followed to periodontal irritation of the affected tooth. In the second case it caused a delayed eruption of teeth into an anomalous position. In the third case of an adult female patient the talon cusp was partially abraded and no problems were therefore caused. In the fourth male patient, where the eruption of the affected lateral incisor into oral cavity was delayed, the talon cusp was diagnosed on X-ray picture as a suspected superfluous tooth or another eruption obstacle. The diagnosis of talon cusp was established during surgical intervention, which clarified spatial conditions in the frontal area of upper dental arch. Due to the squeezing the talon cusp was wedged into the middle incisor and temporary canine with not yet resorbed root. The temporary canine was extracted in order to enable spontaneous eruption of the affected incisor. The authors discuss the appearance of the talon cusp on X-ray picture and a possibility to confuse it for a superfluous shape in not yet erupted teeth. They also indicate that this shape anomaly causes a delayed eruption of the affected tooth, often into an abnormal position.

        Key words: talon cusp – developmental anomaly of tooth shape – obstacle to eruption – tooth eruption