Talon cusp can be seen in:

Talon cusp is an additional cusp that is usually located on the lingual surface of anterior teeth. It extends atleast half the distance from the cemento-enamel junction to the incisal edge. It is composed of normal enamel and dentin and contains a horn of pulp tissue. It is seen in:  Mohr syndrome Rubinstein Taybi syndrome Sturge-Weber syndrome