Talon cusp is a rare dental anomaly resulting in an extra cusp or cusp-like projection on an anterior tooth, located on the inside surface of the affected tooth. Sometimes it can also be found on the facial surface of the anterior tooth.The term talon cusp refers to the same condition as dens evaginatus; however, talon cusp is more specifically the manifestation of dens evaginatus on the anterior teeth. Talon cusp can be simply defined as hyperplasia of the cingulum of an anterior tooth. Although talon cusp may not appear serious, and in some people may be completely benign, it can cause clinical, diagnostic and functional problems, and alters the appearance of a persons teeth. The condition was first described by W.H. Mitchell in 1982 and named by J. Kimball Mellor B.S., D.D.S. and Louis W. Ripa, D.D.S., M.S. due to its similar appearance to an eagles talon. Some sources define a talon cusp as an extra cusp which extends at least half the distance between the cementoenamel junction and the incisal edge of the tooth. Other sources classify all enlarged cingula as talon cusps, and classify them according to the degree of enlargement.The incidence of talon cusp has been found to range from 1% to 6% of the population. Talon cusp tends to occur on permanent teeth only, being very rare in deciduous teeth. In most cases, the involved teeth are the permanent maxillary lateral incisors (55%), followed by maxillary central incisors (33%), mandibular incisors (6%), and maxillary canines (4%).
Signs and symptoms
Talon cusp will show physical signs of the irregular dental formation of the teeth and cause other symptoms of the disease that could possibly lead to dental problems in the future, depending on severity of the deformity. Most commonly, the extra cusp is located on the lingual surface, giving a three-pronged appearance. Rarely, however, the extra cusp may be situated on the facial surface, or there may be extra cusps on both lingual and facial surfaces. There may be a deep groove between the talon cusp and the rest of the tooth. The extra cusp typically contains pulp tissue. When viewing talon cusp from the occlusal, the projection will appear "x-shaped", as well as appears conical, and mimic the shape of an eagles talon.Symptoms of talon cusp include:

Interference with occlusion or bite
Irritation of soft tissues and tongue
Accidental cusp fracture
Susceptible to dental caries

Cause
The cause of talon cusp is unknown. The anomaly can occur due to genetic and environmental factors but the onset can be spontaneous. Prevention is difficult because the occurrence happens during the development of teeth. Talon cusp affects men and women equally, however the majority of reported cases are of the male gender. Individuals of Asian, Arabic, Native American and Inuit descent are affected more commonly. Talon cusp is also highly observed in patients with orofacial digital II syndrome and Rubinstein Taybi syndrome. Other anomalies that occur with talon cusp can include peg laterals, supernumerary teeth, dens envaginatus, agenesis and impaction.