|Year : 2013 | Volume
| Issue : 2 | Page : 109-112
Bilateral talon cusp on maxillary incisors: A unique case report
Anusha Rangare Lakshman, Sham Kishor Kanneppady, Chaithra Kalkur
Department of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Kerala, India
|Date of Web Publication||4-Jul-2014|
Anusha Rangare Lakshman
Department of Oral Medicine and Radiology, Century International Institute of Dental Science and Research Centre, Poinachi, Kasaragod - 671 541, Kerala
Source of Support: None, Conflict of Interest: None
The talon cusp, or dens evaginatus of anterior teeth, is a relatively rare dental developmental anomaly characterized by the presence of an accessory cusp-like structure projecting from the cingulum area or cementoenamel junction. This cusp resembles an eagle's talon and hence is named after it. It usually contains normal enamel, dentin and, sometimes, extending into the pulp. Most of the cases are unilateral and only one-fifth of the cases are bilateral. We are hereby highlighting a rare and distinctive presentation of talon cusp involving the bilateral maxillary incisors.
Keywords: Bilateral, maxillary incisors, talon cusp
|How to cite this article:|
Lakshman AR, Kanneppady SK, Kalkur C. Bilateral talon cusp on maxillary incisors: A unique case report. Int J Oral Health Sci 2013;3:109-12
| Introduction|| |
Development of tooth is a complex process. Any aberration in the various morphologic stages of tooth development can result in unique manifestations. Talon cusp (dens evaginatus of anterior tooth) is a well-delineated additional cusp that is located on the surface of an anterior tooth and extends at least half the distance from the cementoenamel junction to the incisal edge.  In 1892, this unusual dental anomaly was first described by Mitchell, which was thereafter named a talon cusp by Mellor and Ripa due to its resemblance to an eagle's talon. , The exact etiology is unknown. But, it is thought to occur during the morphodifferentiation stage as a result of outward folding of the inner enamel epithelial cells (precursors of ameloblasts) and transient focal hyperplasia of mesenchymal dental papilla (precursors of odontoblasts) or a combination of genetic and environmental factors (multifactorial). 
The incidence of dens evaginatus varies from 1% to 8%.  Three-fourths of all reported cases are located in the permanent dentition. The cusps predominantly occur on the permanent maxillary lateral (55%) or central (33%) incisors, and less frequently on the mandibular incisors (6%) and maxillary canine (4%).  Talon cusps occurring on the lingual surfaces of the teeth is pathognomonic.  Most of the cases are unilateral and only one-fifth of the cases are bilateral.  We are hereby reporting a very rare presentation of talon cusp involving the maxillary incisors bilaterally.
| Case Report|| |
A 35-year-old male patient reported to the Department of Oral Medicine and Radiology with complaints of pain in the lower right back tooth jaw region since 3 months. The pain was dull, localized and intermittent in nature. There were no other associated symptoms. Medical, family and dental histories were noncontributory. On intraoral examination, discoloration of the upper left central incisor was noticed with a history of fall 5 years back [Figure 1], and class I deep dental caries was noticed in relation to the right mandibular first molar. Well-defined unilateral accessory anomalous cusp was noticed on the lingual surface of the upper maxillary right and left permanent central and lateral incisors. On both laterals, it was extending from the cementoenamel junction (CEJ) to 7 mm short of the incisal edge, perpendicular to the mesiodistal plane of the tooth, measuring approximately 3 mm in length from the base to the tip, 2 mm in width and projecting 0.5 mm away from the crown lingually, whereas on both the central incisors it was extending from the CEJ up to the middle one-third of the crown. It was measuring approximately 4 mm in length from the base to the tip, 2 mm in width and projecting 0.5 mm away from the crown lingually [Figure 2]. The left maxillary central incisor showed no response to electric pulp testing, while the other maxillary incisors responded normally. Periapical radiograph revealed the talon cusp as a "V"-shaped radioopaque structure on the central incisors and "U"- shaped radioopaque structure on the lateral incisors superimposing the crown [Figure 3] and [Figure 4]. Calcification of the pulp canal was seen in the left maxillary central incisor. The patient was referred for root canal treatment in relation to the right mandibular first molar and left maxillary central incisor.
|Figure 2: Talon cusps on the lingual surface of maxillary incisors bilaterally|
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|Figure 3: Periapical radiograph showing the talon cusp as a "V"-shaped radiopaque structure on the right central incisor and a "U"-shaped radioopaque structure on the right lateral incisor superimposing the crown|
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|Figure 4: Periapical radiograph showing the talon cusp as a "V"-shaped radioopaque structure on the left central incisor with calcification of the pulp canal and a "U"-shaped radioopaque structure on the left lateral incisor superimposing the crown|
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| Discussion|| |
Talon cusp is a relatively uncommon developmental anomaly. 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 CEJ to the incisal edge.  Various terms have been used for this odontogenic anomaly, such as prominent accessory cusp-like structure,  exaggerated cingula,  additional cusp,  cusp-like hyperplasia,  accessory cusp  and supernumerary cusp.  The size and shape of this anomaly shows wide variation and hence it has been classified into three types by Hattab et al.
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 CEJ to the incisal edge.
Semi talon-refers to an additional cusp of a millimeter or more extending less than half the distance from the CEJ to the incisal edge. It may blend with the palatal surface or stand away from the rest of the crown.
Trace talon-an enlarged or prominent cingula and their variations, i.e. conical, bifid or tubercle like.
However, Mayes  in 2007 categorized facial talon cusps into three stages, starting from the slightest to the most extreme forms. In the present case, the talon cusp on maxillary centrals was classified as type 1 and type 2 for lateral incisors.
The etiology of the talon cusps remains unknown. It has been suggested that the condition has a multifactorial etiology, combining both genetic and environmental factors.  In this case, family history was noncontributory. Talon cusps originate during the morphodifferentiation stage of tooth development. They may occur as a result of outward folding of inner enamel epithelial cells (precursors of the ameloblasts) and transient focal hyperplasia of the peripheral cells of the mesenchymal dental papilla (the precursors of the odontoblasts). 
The prevalence rate of talon cusp ranges between 0.06-7.7% and 0.6% in Mexicans, 7.7% in northern Indians, 2.5% in Hungarians, 5.2% in Malaysians and 2.4% in the Jordanian population. , Seventy-five percent of the talon cusp is seen involving the permanent dentition than the primary dentition, and 92% affect the maxillary teeth. , The permanent maxillary lateral incisor is the most frequently affected, while the maxillary central incisor is the most affected in the primary dentition. Talon cusp usually occurs on the palatal or lingual surfaces of the anterior teeth, with very few cases reported on the facial tooth surface. , In a review of 108 reported cases of talon cusps as case reports in the literature between the years of 1970 and 1995, the authors indicated that about 7.7% of the cases were in the permanent teeth and 20% of them were bilaterally distributed.  A study performed to investigate the prevalence of the talon cusps in a sample of Indian dental patients showed bilateral involvement of the talon cusp in 24 teeth in 2740 patients.  The talon cusp is most commonly seen associated with Rubinstein-Tyabi syndrome, Mohr syndrome (oral facial-digital II syndrome), Sturge Weber syndrome More Details (encephalo-trigeminal angiomatosis), incontinentia pigmentia-chromians and Ellis-van Creveld syndrome More Details.  In the present case, no such association was noticed.
The presence of a talon cusp is not always an indication for dental treatment unless it is associated with problems such as compromised esthetics, occlusal interference, tooth displacement, caries, periodontal problems or irritation of the soft tissues during speech or mastication. ,, In the case presented here, it was asymptomatic.
Radiographically, it may appear typically as a V-shaped radioopaque structure, as in true talon or semi-talon, or be tubercle-like, as in trace talon, originating from the cervical third of the root superimposed over the normal image of the crown of the tooth. A similar radiographic feature was seen in the present case involving the maxillary centrals and U-shaped radioopaque structure involving the maxillary laterals. 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. 
Treatment and management of talon cusp usually depends on individual presentation and complications, and should be as conservative as possible. If small talon cusps are asymptomatic then there is no need of any treatment. , In this case, no treatment was performed as it was asymptomatic. Simple prophylactic measures such as fissure sealing and composite resin restoration can be performed for deep developmental grooves. In case of occlusal interference, reduce the bulk of the cusp gradually and periodically, and application of topical fluoride gel is indicated to reduce sensitivity and to stimulate reparative dentin for pulp protection or outright total reduction of the cusp and calcium hydroxide pulpotomy. It may also become necessary sometimes to fully reduce the cusp, extirpate the pulp and carry out root canal therapy. Orthodontic correction may become necessary when there is tooth displacement or malalignment of the affected or neighboring teeth. ,
| Conclusion|| |
The need for close periodic examination and early detection of all possible developmental defects such as talon cusp involving the permanent dentition and the importance on preventive measures should be stressed. Bilateral talon cusps, although unusually seen, needs to be diagnosed and kept under observation to prevent further complications. Our report highlights this unusual anomaly occurring bilaterally involving the maxillary incisors.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]