TALON CUSP ON PERMANENT MAXILLARY CANINE: A RARE CASE REPORT

Case Report

A 36 years old male patient presented to a private dental clinic for oral prophylaxis. Clinical & radiographic examination of the oral cavity revealed a well-defined unilateral accessory cusp on the palatal surface of the maxillary left permanent canine. It was pyramidal in shape with a round tip and was in close approximation to the tooth surface. It measured approximately 3mm in width and 4.5mm in length from the cingulum towards the incisal edge. Shallow developmental groove was present at the junction of the cusp and the palatal surface of the crown. No dental caries was observed. It did not cause any occlusal interference nor irritated the tongue during speech or mastication. The tooth responded normally to electric pulp testing. No other dental abnormalities were evident. Medical and family histories were noncontributory. As the tooth did not pose any significant clinical problems, corrective treatment was not instituted and the patient was advised for regular check up.
 
The talon cusp is a relatively rare developmental morphological anomaly of the tooth, characterized by an additional cusp-like projection, arising on the labial/palatal/lingual surface of maxillary or mandibular teeth. Its shape resembles the English alphabets "T", "Y" or "X" when viewed from the incisal aspect. It has an average of 3.5 mm width and 6.0 mm length. It is composed of normal enamel and dentine with a varying degree of pulp tissue.

Talon cusp results from evagination of the inner enamel epithelial cells in the morphodifferentiation stage of odontogenesis. Its high incidence in the lateral incisors may be due to compression of the tooth germ between the central incisor and canine. Although the exact etiology is uncertain, multi factors like genetic, trauma or localized insults of the tooth germ, and hyperactivity of the dental lamina has been suggested.

Talon cusp may be found as an independent condition, but it appears to be more prevalent in patients with Rubinstein-Taybi syndrome, Mohr syndrome, Sturge-Weber syndrome and incontinentia pigmenti achromians.

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