Labial talon cusps: a South American archaeological case in the deciduous dentition and review of a rare trait.

Talon cusps are rarely reported developmental anomalies of the anterior dentition. They occur most commonly on the lingual aspect of the tooth but may also affect the labial aspect, and double (lingual and labial) talon cusps have also been reported. This study presents the first case of a labial talon cusp affecting the maxillary deciduous central incisor to be described in the literature. It was identified in a child skeleton from the archaeological site of Borgatta, north-west Argentina. The aetiology of talon cusps remains uncertain, with a combination of both genetic and environmental factors hypothesised to be involved. As a number of cases of labial talon cusps have now been published, this study presents a survey of cases in the literature to characterise the expression of this trait, and compares it with that of lingual talon cusps. The aim is to offer further insight into the relationship between lingual and labial talon cusps and their aetiologies. Differences between these traits in sex distribution, frequency of maxillary and mandibular cases, and the most commonly affected teeth are demonstrated.