Talon cusps were observed in a 10-year-old boy and his 12-year-old sister. Although the sister's affected tooth was asymptomatic and free of any occlusal interference, the boy's tooth presented some problems. The affected tooth had displaced the occluding mandibular tooth lingually, and this had resulted in a mid-line shift. To overcome the problem, the talon cusp was ground off and a prophylactic odontotomy performed. Orthodontic treatment was later carried out.