This unusual dental anomaly showing an accessory cusp-like structure projecting from the cingulum to the cutting edge was first described by Mitchell in 1892 1. It was thereafter named a Talon cusp by Mellor and Ripa 2 due to its resemblance to an eagle's talon. Since then, this odontogenic anomaly has been given several descriptions, such as, prominent accessory cusp-like structure 3, exaggerated cingula 4 additional cusp 5, cusp-like hyperplasia 6, accessory cusp 7 and supernumerary cusp 8. It has been defined as a supernumerary accessory talon-shaped cusp projecting from the lingual or facial surface of the crown of a tooth and extending for at least half the distance from the cemento-enamel junction to the incisal edge 7. There is a wide variation in the size and shape of this anomaly. Due to this variation, and in order to have a diagnostic criteria, it has been classified into 3 types by Hattab et al 9:

Type1: Talon – refers to a morphologically well-delineated additional cusp that prominently projects from the palatal (or facial) surface of a primary or permanent anterior tooth and extends at least half the distance from the cemento-enamel junction to the incisal edge.

Type 2: Semi talon – refers to an additional cusp of a millimeter or more extending less than half the distance from the cemento-enamel junction to the incisal edge. It may blend with the palatal surface or stand away from the rest of the crown.

Type 3: Trace talon – an enlarged or prominent cingula and their variations, i.e. conical, bifid or tubercle-like.

Radiographically, it may appear typically as a v-shaped radiopaque structure, as in true talon or semi- talon, or be tubercle-like, as in trace talon, originating from the cervical third of the root. The radiopaque v-shaped structure is superimposed over the normal image of the crown of the tooth. The point of the 'V' is inverted in mandibular cases. This appearance varies with the shape and size of the cusp, and the angle at which the radiograph is taken.

It is composed of enamel, dentine and a varying amount of pulp tissue 1011. The extent of pulp extension into the cusp is however difficult to determine because of its superimposition over the main pulp chamber 12. While some indicated that talon cusps contain pulp tissue 21013, some found no evidence of pulp extension into the cusp 1415. However, it has been suggested that large talon cusps, especially those that stand away from the tooth crown are more likely to contain pulp tissue 912. A review of the literature showed that over the last two decades, increasing reports have been made of the occurrence of the condition. The reported prevalence outside Africa is between 0.06% in Mexicans 16 and 7.7% in a northern Indian population 17. It has also been found to be relatively common in the Chinese 56 and Arab 9, and predominantly in the male population 18. These wide variations in prevalence could be due to individual differences in definitions of observation, from enlarged cingula to semi- or true talons 17. If data is taken from those who reported for treatment only, a high prevalence might be observed. Patients may seek treatment when there is a problem, usually with large cusps. No prevalence data has been found in the literature for Africans.

A healthy looking 29 year old Nigerian male presented at the dental outpatient clinic of the Lagos University Teaching Hospital for the purpose of a dental check-up. It was his first visit to the dentist. He did not present any significant medical history. Oral examination showed a fair oral hygiene, no carious lesion, and all the permanent teeth were present. The mandibular left central incisor was displaced lingually with an accessory cusp on the facial aspect which had an attrition facet on the incisal edge. The cusp projected from the cemento – enamel junction and curved towards the incisal edge of the incisor (Figure 1). There was also attrition of the incisal half of the palatal aspect of the maxillary left central incisor. There was a negative family history of such dental anomaly from the patient and there was no associated systemic disorder. A periapical radiograph revealed an inverted V-shaped radiopaque structure on the mandibular left central incisor (Figure 2). The extent of pulp tissue into the cusp could not be determined on the radiograph. A diagnosis of type 1 talon cusp was made. The condition and the planned periodic and gradual reduction of the cusp with topical fluoride application and Composite resin facing was explained to the patient. Orthodontic alignment of the displaced central incisor was also planned. With his consent, after oral prophylaxis, a minimal reduction of the talon cusp was carried out using a diamond bur in a high-speed water-cooled handpiece. Acidulated Phosphate Fluoride (APF) gel was applied to the surface of the reduced cusp and the maxillary left central incisor. The patient however failed to turn up for further treatment. It was assumed that as the patient was not initially concerned with the aesthetic effect of the cusp, the outcome was not important to him.

Reports of mandibular talon cusps are rare in literature. Only ten had been reported, including the present case, with only one on a primary incisor [Table 1]. 1115414849505152. It is agreed that it is more common in maxillary teeth. Facial talons are also rare: only six cases having been reported before this case 737404952. It is even more rare in mandibular teeth.

There was no associated systemic or local condition in this patient as is the case in most previous reports. Most cases occur in isolation of other conditions 53. The patient in this report also did not give a history of its occurrence in any member of his family. Of all the cases reported from Nigeria, only two females were affected. This finding supports earlier reports of a higher prevalence of the condition in males. Mays reported a statistically significant bias in favour of males 54.

The present case is a type 1 talon. Although such large cusps which stand away from the tooth had been shown to contain an extension of the pulp, superimposition of the image of the cusp over the main tooth made it difficult to determine the extent of pulp tissue in the anomalous cusp. The constant attrition on the cusp may also mean that there may be reparative dentine which would have taken up part of the pulp space in the cusp.

The presence of a talon cusp is not always an indication for dental treatment unless it is associated with problems such as compromised aesthetics, occlusal interference, tooth displacement, caries, periodontal problems or irritation of the soft tissues during speech or mastication 3742. Occlusal interference can damage the periodontium, cause infra-occlusion of the opposing tooth and also temporo-mandibular joint pain 2555. Severe attrition or fracture of the enamel surface can cause exposure of the dentine-pulp complex and consequently, pulp necrosis 565758. In this case, the cusp was prominent and sharply defined and projected from the cervical region to the incisal edge of the tooth. This resulted in occlusal interference, which caused the attrition of the tip of the cusp and the opposing maxillary incisor, and displacement of the mandibular central incisor. The patient was however less concerned due to the painless complications. This explained the lack of compliance with appointment. It is necessary to evaluate and treat talon cusps soon after eruption to prevent these complications.

The management and treatment outcome of talon cusp depends on the size, presenting complications and patient cooperation.

The author(s) declare that they have no competing interests.