Talon cusp affecting the primary maxillary central incisors in two sets of female twins: report of two cases.

T alon cusp refers to a cusp-like structure project ing from the cingulum area of a maxillary or mandibular anterior tooth. Shafer et al. and Mellor and Ripa reported that talon cusp is uncommon and occurs in maxillary and mandibular permanent incisors. Most cases of the anomaly have been reported in the permanent dentition. Ninety percent of the talon cusps occur in anterior permanent teeth, and 91% of the affected teeth are in the maxilla.' However, Henderson first described a case in a primary maxillary incisor. The affected tooth was a maxillary left central incisor. In 1987, Morin reported a case of talon cusps affecting both primary maxillary central incisors. Talon cusps are particularly susceptible to caries due to the presence of developmental grooves or fissures at the junction of the cusp and the lingual tooth surface.Talon cusps have been reported to contain a pulp horn.-They have a multifactorial etiology combining both genetic and environmental factors.This anomaly may be due to hyperactivity of the dental lamina, which occurs most commonly in the anterior region. An increased incidence of talon cusp has been reported in Mohr syndrome and RubinsteinTaybi syndrome. This report describes cases of two sets of twins (from two families) of talon cusp affecting the primary incisors.