Syed Nabeel, Usha Hegde, Paras Mull, Gazala Danish 
Abstract
Talon cusp is an anomalous hyperplasia manifesting as an accessory cusp-like structure projecting from the lingual or facial surface of anterior teeth in both the primary and permanent dentition. Cases of talon cusp affecting two generations in each of the two different families, both belonging to ethnic South Indian population are reported. This is suggestive of a probable genetic etiology. The expression of the talon cusp was more prominent in the second generation. All the cases presented in this case report are the progeny of non-consanguineous marriages. Clinical and radiographic features are described. Considering the varied clinical presentations, association with other dental anomalies and the lack of precise criteria in categorizing talon cusp, a comprehensive classification is proposed.
Key Words: Developmental; Disorders; Genes; Hereditary; Talon Cusp; Genetic Etiology; Classification; Human Dental Anomalies;
Syed Nabeel, Usha Hegde, Paras Mull, Gazala Danish. Talon Cusp Affecting Two Generations: Report of Two Cases and Proposed Comprehensive Classification. International Journal of Oral & Maxillofacial Pathology; 2011:2(3):36-41. ©International Journal of Oral and Maxillofacial Pathology. Published by Publishing Division, Celesta Software Private Limited. All Rights Reserved.
Received on: 20/06/2011 Accepted on: 03/08/2011
Introduction
Talon cusp is an uncommon dental anomaly manifesting as an accessory cusp like structure, projecting from the lingual or facial surface of anterior teeth of either dentition.1 The etiopathogenesis is multifactorial, and is thought to be polygenetic with some environmental influences.2 It has a definite predilection for permanent maxillary lateral incisor and is more common in males.1Clinically it can pose esthetic and functional problems to the patient.1,3,4,5 Histologically, it is composed of normal enamel and dentin and it may or may not contain pulpal tissue.3 Radiographically, the talon cusp is usually superimposed over the tooth on which it occurs.6 This article reports talon cusp affecting two generations, in both the families.
Case reports
The case no. one to four belongs to family one (Table 1), whereas the case no. five and six belong to family two (Table 2). The examination of the other members from both the families did not reveal any significant findings. In all the six patients, the vitality of the teeth with the talon’s cusp was found to be positive and there was no significant attrition noted on the taloned teeth or on the opposing teeth. None of the cases were associated with any syndromes. There was no history of consanguineous marriage among parents in either family. Based on Hattab et al1 classification, cases one, two, five were true talon, cases four and six were semi talon, and case three was trace talon.
Discussion
Talon cusp is defined as an uncommon dental anomaly manifesting as an accessory cusp-like structure, projecting from the lingual or facial surface of anterior teeth, on either dentition.7 In 1970 Mellor and Ripa named the accessory cusps as talon cusp because of itsresemblance in shape to an eagle’s talon.8 As in the case of any other abnormality of tooth shape and size, talon cusp occurs early in odontogenesis during the morphdifferentiation stage.1 Another possible cause of the condition that is discussed is hyperproductivity of the anterior segment of the dental lamina.9 Bilateral distribution of talon cusp in some cases, its association with other dental abnormalities, talon cusp occurring in family members, twins, off springs from consanguineous marriages and in some genetic syndromes support genetic etiology of the condition.2,4,9,10
We report talon cusp affecting two different families. The expression of the talon cusp was more exaggerated in the off springs (True Talon) than in the parents (Semi and Trace talon) in both the families. In both the families
the talon cusp was seen in two generations, strongly suggesting a genetic etiology with a probable polygenetic mode of inheritance as the talon cusp was seen associated with other developmental dental anomalies. However, there was no history of consanguineous marriages among the parents. Prevalence of talon cusp is low, affecting less than 1% to approximately 8% of the population.11,12 We present six cases of talon cusp occurring in ethnic South Indian population.
All the six cases reported showed talon cusps on permanent anterior teeth; with five cases affecting maxillary anterior teeth and one case affecting the mandibular anterior tooth. Three cases reported here were seen affecting females and others affecting males. Talon cusp is not an entirely innocuous defect. It may present a number of problems both to the patient and the clinician. They include compromised aesthetics, occlusal interferences, displacement of affected tooth, carious developmental grooves, pulpal necrosis and periapical pathosis, periodontal problems due to excessive occlusal forces, advanced attrition leading to pulp exposure, irritation of the tongue during speech and mastication, interference with tongue space, problems in breast feeding, accidental cusp fracture and temporomandibular joint pain.1,3,4,5 All the cases did not have any clinical implications with the exception of the cases one and two, which posed aesthetic problem to the patients.
Case
|
Age/
Sex
|
Tooth no.
|
Clinical presentation
|
Other dentalanomalies
|
IOPAR findings
|
1
|
25yrs / M(son)
|
21
|
Palatal surface revealed a well delineated projection extending throughout the length of the clinical crown, giving T-shaped appearance to the crown whenviewed incisally. (True talon) The labial surface showed a facial groove. (Fig 1)
|
Exaggeratedcusp of Carabelli on tooth 26
|
Radiopaque V-shaped areasuperimposing the crown.
|
2
|
23yrs / F(daughter)
|
31
|
The talon tooth was rotated and the lingual surface exhibited an exaggerated cingulum extending half way from the cervical margin of the crown to the incisal edge. (semi–talon) (Fig 2)
|
-
|
Radiopaque V-shaped areasuperimposing the crown.
|
3
|
56yrs / F(mother)
|
12,11,21,22
|
Small tubercle-like projections from the cingula. (Trace talon) (Fig 3)
|
Deep palatal pits on tooth 12 and 22
|
Small cone-shapedradiopacitiessuperimposing the crowns.
Type 1 - Dens invagianatus
|
4
|
58yrs / M(father)
|
11
|
Cusp-like structure extending up to the middle third on the palatal surface. (Semi- talon) (Fig 4)
|
Exaggeratedcusp of Carabelli on tooth 16 and26.
|
Radiopaque V-shaped areasuperimposing the crown
Pulp stones in relation to 11 & 21.
|
Table 1: Family one having talon cusp in four members
Case
|
Age/Sex
|
Tooth no.
|
Clinical presentation
|
Other dentalanomalies
|
IOPAR findings
|
5
|
14 yrs / M
(son)
|
12
|
Palatal surface showed two separate cusp-like structures depicting a double talon. They were separated by a deep developmental groove. Cervico-incisally the mesial talon cusp was higher than the distal and it was connected to the incisal edge. (Fig 5)
|
Labialgroove was seen on the crown.
|
RadiopaqueW-shaped areasuperimposing the crown.
|
6
|
40 yrs / F
(Mother)
|
21
|
Double talon. (Fig 6)
|
-
|
-
|
Table 2: Family two having talon cusp in two member.
Apart from the classical talon cusp occurring on the lingual surface of maxillary or mandibular anterior teeth in either dentition, there are various reports of uncommon presentations of talon cusp. Talon cusp has been noted to occur on a single tooth or bilaterally on many teeth in the same patient.1 Talon cusp has been found to occur as an isolated dental anomaly or in association with other dental anomalies and/or syndromes.1,10,13 Although Hattab et al1 classified of talon cusp as True talon, Semi talon and Trace talon gives an insight to the degree of formation and extension of the talon cusp on the lingual surface of the anterior teeth in either dentition, it does not tell us all the details associated with its occurrence such as – the particular dentition involved (deciduous or permanent), the type of the tooth involved (morphologically normal or an anomalous tooth), the surface of the tooth affected (lingual or facial) and its association with other dental anomalies or syndromes. Taking all the above factors into consideration, there appears a need for a comprehensive classification encompassing all the conditions with which it occurs. This kind of a comprehensive classification will help the clinician in identifying this particular anomaly, by putting forth the criteria for identifying and categorizing talon cusp. It will also be of help in studying the prevalence of this particular dental anomaly.
Hence, the authors Gazala, Usha, Paras & Nabeel suggest a classification for talon cusp which is modified, precise and comprehensive. According to which the talon cusp can be classified based on two parameters:
- I. Based only on the extension of the talon cusp as:
Type 1 (Talon / True talon): A morphologically well delineated additional cusp that prominently projects from any of the tooth surface of a primary or permanent anterior tooth and extends at least half the distance from the cementoenamel junction to the incisal edge.1
Type 2 (Semi talon): A morphologically well delineated additional cusp that prominently projects from any of the tooth surface of a primary or permanent anterior tooth and extending less than half the distance from the cementoenamel junction to the incisal edge. It may blend with the palatal surface or stand away from the rest of the crown.1
Type 3 (Trace talon): Enlarged or prominent cingula and their variations i.e., conical, bifid or tubercle-like.1
- II. Based on the surface and anomaly of the involved tooth:
Type A: Talon cusp occurring on the lingual or palatal surface of the permanent anterior teeth, without any anomaly on the same tooth
Type B: Talon cusp occurring on the facial surface of the permanent anterior teeth, without any anomaly on the same tooth.
Type C: Talon cusp occurring on lingual or palatal surface of an anomalous tooth i.e. talon cusp occurring on a supernumerary tooth, a fused tooth, geminated tooth, dens invaginated tooth or on a tooth with a facial groove / cleft.
Type D: Talon cusp occurring on facial surface of an anomalous tooth i.e. talon cusp occurring on a supernumerary tooth, a fused tooth, geminated tooth, dens invaginated tooth or on a tooth with a facial groove / cleft. (Note: Type a, Type b, Type c and Type d is used to describe the same, but on a deciduous tooth) (Tabel 3)
Type 1
|
Type 2
|
Type 3
| |
Type A /Type a
|
Type 1A / Type 1a
|
Type 2A / Type 2a
|
Type 3A / Type3a
|
Type B / Type b
|
Type 1B / Type 1b
|
Type 2B / Type 2b
|
Type 3B / Type 3b
|
Type C / Type c
|
Type 1C / Type 1c
|
Type 2C / Type 2c
|
Type 3C / Type 3c
|
Type D/ Type d
|
Type 1D/ Type 1c
|
Type2D/ Type 2d
|
Type 3D/ Type 3d
|
Table 3: Combining both the above parameters we can simply express the different types of talon cusp in a grid system:
Use of suffixes “N” and “S”
The suffix "N" is used in the above classification when the talon cusp on a tooth occurs along with other dental anomalies, in the same patient such as bifid cingulum, tubercle-like cingulum, cingulum hypertrophy, accessory cusps of premolars, prominent cusps of Carabelli, microdont, agenesis of teeth, odontome and double tooth. The suffix "S" is used when the talon cusp is seen as a part of few syndromes such as Sturge-Weber syndrome, Mohr syndrome, Ellis-Van Creveld syndrome, Rubinstein-Taybi syndrome and incontinentia pigmenti achromians.
Figure 1: Occlusal view of maxillary teeth showing Type 1 talon cusp on the palatal surface of maxillary left central incisor. (Mirror image)
Figure 2: Occlusal view of the cast showing rotated mandibular left central incisor with Type 1 talon cusp on the lingual surface.
Figure 3: Occlusal view of maxillary teeth showing trace talons on the cingula of all the maxillary incisors. (Mirror image)
In case the patient shows both the association of talon cusp with other dental anomalies and a syndrome, then the suffix “NS” is used. Examples: Type 1A, Type 1B-S, Type 3A-N, Type 2C-NS, Type 2b, Type1AB, Type 2A3B, Type 3D etc. In case of multiple talon teeth in the same patient, each tooth has to be classified separately.
Figure 4: Occlusal view of maxillary teeth showing semi talon on maxillary right central incisor. (Mirror image)
Figure 5: Occlusal view of maxillary teeth showing Type 1 talon cusp on the palatal surface of maxillary right lateral incisor. (Mirror image)
Figure 6: Occlusal view of maxillary teeth showing Type 2 talon cusp on the palatal surface of maxillary left central incisor. (Mirror image)
Based on the above proposed classification, the cases presented are;
Case 1: Type 1C-N (1 - True talon, C - on palatal aspect of permanent maxillary left incisor associated with facial groove and N - presence of prominent cusp of Carabelli on permanent maxillary left first molar) (Fig 1).
Case 2: Type 1A (1 - True talon, A - on the lingual surface of permanent mandibular incisor) (Fig 2).
Case 3: Type 3A on permanent maxillary central incisors and right lateral incisor. (3 - Trace talon, A - on the palatal aspect of permanent maxillary incisors). The permanent maxillary left lateral incisor is Type 3C (3 - Trace talon, C - on palatal aspect of an anomalous permanent maxillary incisor tooth, dens invaginatus) (Fig 3).
Case 4: Type 2A-N (2 - Semi talon, A - on palatal aspect of a permanent maxillary incisor and N - presence of cusp of Carabelli on permanent maxillary right and left first molars) (Fig 4).
Case 5: Type 1C (1 - True talon, C - on palatal aspect of permanent maxillary incisor associated with facial groove) (Fig 5).
Case 6: Type 2A (2- Semi talon, A - on palatal aspect of permanent maxillary incisor) (Fig 6).
Treatment may differ depending on each case. Small talon cusps are usually asymptomatic, necessitating no treatment. However, large, prominent and separated talon cusps require definitive treatment.1
Conclusion
In conclusion, we report six cases of talon cusp, affecting the permanent incisors in two generations, in each of the two different families. The talon cusps showed varied clinical presentations with more prominent extension in the second generation than the first generation. Three of the six cases were also associated with other dental anomalies. The presence of talon cusp in two generations of two different families with history of non-consanguineous marriage strongly supports the genetic etiology. A polygenetic pattern of inheritance could be suspected because of the varied presentation of talon cusp and its association with other dental anomalies. Further prevalent and genetic studies, with larger samples would definitely help in understanding and arriving at a conclusive etiopathogenesis. Many authors who have reported talon cusp have stressed on the need for a precise criteria to clearly identify and categorize talon cusp, including all the variant forms, the dentition involved and its association with other pathological conditions. Hence, we propose a classification based on precise criteria to categorize the talon cusp.
Author Affiliations
1. Dr. Syed Nabeel, Director, 2. Dr. Usha Hegde, Consultant Oral & Maxillofacial Pathologist, 3. Dr. Paras Mull J, Consultant Endodontist, 4. Dr. Gazala Danish, Consultant Oral Diagnostician & Radiologist, Smile Maker Clinics, Mysore, India.
Acknowledgement
We would like to thank all the staff members from the Smile Makers Clinics, Mysore.
References
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Corresponding Author
Dr. Syed Nabeel
Smile Maker Clinics,
#187, 2nd Stage, M.G Road, 2nd Main, Udayagiri, Mysore-570 019, India.
E Mail: dr.syednabeel@gmail.com
Phone: +91-98451-06626
Source of Support: Nil, Conflict of Interest: None Declared.
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