Restorative Dentistry

Dens evaginatus of anterior teeth (talon cusp):Report of five casesJuan J. Segura-Egea, DDS, MD, PhDVAIicia Jiménez-Rubio, DDS, MD,José V. Ríos-Santos, DDS, MD, PhD /Eugenio Velasco-Ortega, DDS, MD,

The talon cusp, or dens evaginatus of anterior teeth, is a relatively rare dental developmental anomalycharacterized by the presence of an accessory cusplike structure projecting from the cingulum area or ce-mentoenamel junction. This occurs in either maxiiiary or mandibular anterior teeth in both the primary andpermanent dentition. This articie reports five cases of talon cusp, two of them bilateral, affecting perma-nent maxiiiary centrai and lateral incisors and canines that caused ciinicai problems related to caries orocciusal interferences. (Quintessence int 2003:34:272-277)

Key words; Dens evaginatus, dentai anomalies, occlusal interference, talon cusp

D ens evaginatus is a developmental anomaly char-acterized by the presence of an extra cusp, occur-

ring more frequently in mandibular premolars.' In ca-nines and incisors, dens evaginatus originates usuallyin the palatal cingtilus as a tuhcrcle projecting fromthe palatal surface; however, the anomaly also has af-fected the labial surface of the tooth.-' Mitchell" firstdescrihed this dental anomaly as a "process of horn-like shape, curving from the base downward to theeiitting edge" on the lingual surface of a maxillary cen-tral incisor of a female patient. Mellor and Ripa^named the accessory cusp talon cusp because of its re-semblance in shape to an eagle's talon.

Talon cusp oecurs more frequently in the perma-nent than in the primary dentition and shows apredilection for the maxilla over the mandible.^ Themaxillary lateral incisors are the most frequently in-

'Associate Professor, Dental Patliology anO Therapeutics, Department of

Storratology, Schooi of Oentistty, University of Seville, Seviile, Spain,

^Assooiate Professor, Dental Anatomy, Department of Morpiioiogical

Sciences. School of Medicine, University of Seville, Seville, Spain.

professor of Comprehensive Dentistry, Department of Stomatology,

Sohooi ot Dentistry. University of Seville, Seville, Spain,

Reprint requests: Dr Juan J. Segura-Egea, CI Cueva de Menga n^ 1, por-

tal 3, 6--C. 410£0-Seviiia, Spain E-maii: segura¡j@waraaoo.ss

volved (ÖTVo), followed by the central incisors (24%)and canines (9%).*"

Family histories of cases reported previously re-vealed that sometimes talon cusp affected patientswho had consanguineous parents."-^ Moreover, thereare several data in the literature that support thehereditary character of talon eusp: the anomaly hasbeen described affecting two siblings,'"" two sets offemale twins,'^ and two family members,' and theprevalence of talon cusp is high in some racialgroups.'^"'^ The family involvement and the associa-tion of the talon cusp with other dental abnormalities,suggest that genetics may be a major causative factor.However, sporadic occurrences of this abnormalityprobably are induced by trauma or other localized in-sults affecting the tooth germ. Talon cusp affects bothsexes and commonly is unilateral, but one fifth of thecases are bilateral.'

The anomalous talon cusp is composed of normalenamel and dentin with varying extensions of pulptissue, Shay^ reported that pulp tissue can extend tothe center of the tubercle and, once fractured, thepulp is exposed. When talon cusp interferes with thenormal occlusion, an oeclusal adjustment by grindingthe palatal projection must be performed, with thepossibility of exposure of the dentin-pulp complexand, consequently, pulp necrosis.'^

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• Segura-Egea et al

Fig 1 Case 1, Occlusal view showing a prominent accessorycusp on the palatal surface ot ttie right canine. Darkly stained de-velopmental grooves are evident.

Fig 2 Case 1, Petiapical radiograph

The cases reported in tbe literature as talon cuspare very different since this anomaly varies widely inshape, size, structure, location, and site of origin.' Thetip of the cusp may stand away from the crown or maybe in close approximation to tbe lingual surface.^Some cusps are quite sbarp and spiked, while othersare teatlike and have rounded and smooth tips. Taloncusps may be markedly enlarged or exaggerated cin-gida on tbe maxillary incisors.'" Others bave describedtbem as bornlike, conical, or pyramidal. * Davis andBrook ' stated tbat talon cusp may represent the ex-treme of a continuous variation progressing from anormal cingulum, to an enlarged cingulum, to a smallaccessory cusp, to a talon cusp.

This article reports five cases of talon cusp, two ofthem bilateral, affecting permanent maxillary centraland lateral incisors and canines tbat caused clinicalproblems related to caries or occlusal interferences.

CASE REPORTS

Case 1

A bealthy 21-year-old female was seen for a routinedental examination. Her medical and dental historywere uneventful. The right maxillarj' canine exhibited asmall prominent cusp on tbe palatal surface (Fig 1).The accessory cusp on tbe rigbt canine, conical insbape, was projected from tbe cementoenamel junctionand extended less than halfway to the incisai edge. Thecusp measured 3.3 mm in length (incisocervically), 4.3mm in widtb (mesiodistaliy), and about 2.6 mm inthickness (labiolingually). A small bridge of enamelconnected the accessory cusp to the palatal surface oftbe tooth. Tbe developmental grooves on tbe distal andtbe mesial side of the cusp were darkly stained and

packed with dental plaque. A carious lesion was de-tected clinically in the distal groove. The affected toothwas responsive to electric pulp testing. The cusp didnot irritate the tongue during speech and masticationand did not interfere with the occlusion. Radiograpbsshowed the presence of enamel, dentin, but not pulphorn in the palatal accessory cusp (Fig 2). The left ca-nine did not show talon cusp.

Case 2

A 28-year-old male was seen for oral prophylaxis.Clinical examination disclosed prominent cusphkestructures on the palatal surfaces of both the left max-illary lateral incisor and tbe left maxillary canine (Fig3). The accessory cusp of tbe lateral incisor was pyra-midal in sbape and extended from tbe cementocname!junction one third to tbe incisai edge, ¡t was attacbcdto the palatal surface and extended distally. The cusptip was pointed and slightly sbarp. Tbe cusp measured3.7 mm in length (incisocervically), 3.9 mm in width(mesiodistaliy), and 3.3 mm in thickness {labiolin-gualiy). Noncarious, but stained, developmentalgrooves were observed laterally. A caries lesion wasevident in the mesial surface of tbe tootb.

Tbe accessory cusp of tbe canine also was pyrami-dal in sbape and extended from tbe cementoenameljunction one quarter to tbe incisai edge. It was at-tacbed to tbe palatal surface and extended perpendic-ular to tbe mesiodistal surface of the crown,Noncarious developmental grooves were observed lat-erally. Tbe cusp measured 2.9 mm in lengtb (incisocer-vically), 2.7 mm in widtb (mesiodistaliy), and 2.4 mmin thickness (labiolingually).

Tbe talon cusps did not irritate the tongue duringspeech and mastication, but, due to the reduced over-hite, the taloned teeth, mainly the left lateral incisor.

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Fig 3 Case 2 Anomalous cusplike structures on the paialal aspects of both maxillary left lateral incisor and canine.

Fig 4 Case 3. Taion cusps on .inaxiliary lateral inciscrs (rrirrorphotograph).

Fig 5 Case 4. The taion cusp on nght maxiiiary iaterai ncisor ispointed and siiarp and coincides with the midline (mirror photo-graph).

interfered slightly with the occlusion. An occlusal ad-justment by grinding the palatal projection of the lat-eral incisor was performed in one appointment.

Case 3

A 19-year-old male presented to the dentai clinic for aroutine dental examination at the end of an orthodon-tic treatment. The patient appeared healthy and ofnormal physical development for his age. There wasno reported history of orofacial trauma. The occlusionwas a Class 1 molar relationship. Both maxillary rightand left lateral incisors showed an accessory cusp onthe palatal aspect (Fig 4). The accessory cusp on theleft maxillary lateral incisor measured 2.7 mm inlength (incisocervically), 3.9 mm in width (mesiodls-tally), and 2.2 mm in thickness (lahiolingually). Thetalon cusp was pyramidal in shape and located on thecenter of the crown, with the tip of the cusp attachedto the crown. The accessory cusp extended from the

cementoenamel ¡unction more than one third to theincisai edge. Noncarious but slightly stained develop-mental grooves were present at the junction of thetalon cusp and the palatal surface of the tooth. Theanomalous cusp on the right maxillary lateral incisormeasured 2.6 mm in length {incisocervically), 3.5 mmin width (mesiodistally), and 2.0 mm in thickness(labiolingually). The talon cusp was conical in shapeand located in the distal half of the crown, with the tipof the cusp attached to the crown. The accessory cuspextended from the cementoenamel junction one thirdto the incisa) edge. The mesial developmental groovewas stained but noncarious. The affected tooth re-sponded normally to electric and thermal puip tests.Both maxillary canines showed a bifid cingulum.Neither of the taloned teeth interfered with the nor-mal occlusion.

Case 4

A 10-year-old male presented for the treatment of sev-eral carious lesions. Clinical examination disclosed aprominent cusplike structure on the palatal surfaee ofthe maxillary right lateral incisor (Fig 5). The taloncusp was pyramidal in shape and extended from thecementoenamel junction halfway to the incisai edge. Itwas attached to the palatal surface and extended per-pendicular to the mesiodistal surface of the crown.The cusp tip was pointed and sharp and coincidedwith the midline of the long axis of the tooth, forminga Y-shaped crown outline. The cusp measured 4.5 mmin length {incisocervically), 4.0 mm in width{mesiodistaily}, and 3.5 mm in thickness (labiolin-gually). Noncarious developmental grooves were ob-served laterally. The tooth appeared normal and re-sponded to electric pulp testing. Due to the reducedoverbite, the talon cusp interfered with the occlusion;

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Fig 6 Case 5. Abnormal paiatai structures on both centraicisors.

Fig 7 Case 5. Periapical radiograpii showing V-shaped ra-diopaque structures superimposed on the image of the affectedcrowns.

wear facets were present on the cusp and the incisaiedge of the opposing tooth. No other dentai variationswere detected. An occlusal adjustment by grindingslightly the accessory cusp of the lateral incisor wasperformed in one appointment.

Case 5

A 20-year-old female presented to the dental clinic foran oral prophylaxis. Both maxillary right and leftcentral incisors showed an anomalous anatomy on thepalatal surface (Fig 6), Very prominent bifid cingulawere apparent on the palatal aspects of both centralincisors. Furthermore, cusplike structures extendingfrom the cementoenamel jimction more than halfwayto the incisai edge were evident. The talon cusp on theleft central incisor was located in the center of theerown and was teatlike in shape, with an enamei ridgeextending from the cementoename! junction morethan one third to the incisai edge. The accessory cuspon the right central incisor had the same form, show-ing a similar enamel ridge pointing to the mesial sideof the incisai edge.

Both taloned teeth showed accentuated marginalridges surrounding a deep iingual fossa taking ashovel-shaped form. In both teeth, noncarious butstained developmental grooves were observed later-ally, A periapical radiograph (Fig 7) showed aV-shaped radiopaque structure superimposed on theimage of the affected crowns, with the "V" pointing to-ward the incisai edge. Both talon cusps were outlinedby two distinct white lines converging from tbe cervi-cal area of the aftected tooth toward the incisai edge.Pulp extension could be traced radiographicaliy to themiddle of the cusps.

The lateral incisors and the canines also showedabnormal structures on their palatal surfaces (Fig 8), A

Fig 8 Case 5. Occiusai view (mirror photograph).

small, sharp and pointed cusplike structure was evi-dent in the cingulum of the right lateral incisor. Theanomalous structure was pyramidal in shape and lo-cated on the center of the crown, with its tip attachedto the crown and extending from the cementoenameljunction more than one third to the incisai edge,Noncarious developmental grooves were present. Theleft lateral incisor and both canines showed bifid cin-gula. Both the lateral incisors and the canines showedaccentuated marginal ridges and shovel-shaped form.

DISCUSSION

Dens evaginatus is an anomaly of great clinical signifi-cance, sometimes causing occlusal interference. Thecleaning of the area between tbe nodule and the toothis difficult, and caries are often found,'*

Talon cusp originates during the morphodifferentia-tion stage of tooth development but the etiology of the

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condition remains unknown.'' In the majority of casesreported, the talon eusp is isolated rather than an inte-gral part of any disorder Nevertheless, the anomaly hasheen reported in patients with Sturge-Weher syndrome(encephalotrigeminal angiomatosis)/ Mohr syndrome(oro facial digital II syndrome),^" Ellis-van Creveld syn-drome,'" and Ruhinstein-Tayhi syndrome. ^ None of thecases reported here were associated with any knownabnormal systemic developmental syndrome.

Control of the complex processes of dental devel-opment appears to be multifactorial, that is, primarypolygenetie with some environmental influence. Taloncusp is usually associated with other dental variations:bifid cingula, dens invaginatus, exaggerated cusps ofCarabelli, and particularly with shovel-shaped maxil-lary incisors, - a polygenlc inheritable trait character-ized by accentuated marginal ridges that surround adeep lingual fossa. ' In case 5, several of these dentalanomalies were present.

As in the case of talon cusp, the maxillary lateralincisors are the most commonly affected with shovel-ing and dens invaginatus.'^^'^^ The susceptibility of thelateral incisors to abnormalities could partly he relatedto compression of the tooth germ of the lateral incisorby the adjacent central incisor and canine, which de-velop about 7 months earlier than the lateral incisor.Increased localized external pressure on a tooth germduring the morphodifferentiation stage may result ineither outfolding of the dental lamina (in the case oftalon cusp) and shoveling or infolding of the dentallamina as in dens invaginatusr^

Hattab et al*" classified the anomaly hased on the de-gree of their formation and extension into three types:type 1 (talon): additional cusp that projects from thepalatal surface of an anterior tooth and extends at leasthalf the distance from the cementoenamel junction tothe incisai edge; type 2 (semitalon): an additional cuspof a millimeter or more hut extending less than half thedistance from the cementoenamel junction to the in-cisal edge; and type 3 (trace talon): enlarged andprominent cingula and their variations.

According to the classification by Hattab et al,' thetalon cusps described in the current cases classified asfollows:

The anomalous conical cusp on the left canine incase 1, the accessory pyramidal cusps on the left max-illary lateral incisor and the left maxillary canine incase 2, the talon cusps presented in case 3, and fhetalon cusp evident on the palatal surface of hoth cen-tral incisors and the right lateral ineisor in case 5 wereclassified as type 2 or "semitalon."

The talon cusp in case 4, pyramidal in shape andextending from the cementoenamei junction morethan halfway to the incisai edge, was classified as type1 or "talon cusp."

Anomalous palatal structures on the left lateral in-cisors and hoth canines in case 5, representing a varia-tion of enlarged or prominent cingula and their varia-tions, could be classified as type 3 or "trace talon."

Large talon cusps may cause clinical problems in-cluding occlusai interference, displacement of the af-fected tooth, irritation oí the tongue during speechand mastication, carious lesion in the developmentalgrooves that delineate the cusp, pulpal necrosis, peri-apical pathosis, attrition of the opposing tooth, andperiodontal problems due to excessive occlusai

Early diagnosis and management of talon cusp isimportant in order to prevent occlusai interference,compromised esthetics, carious developmentalgrooves, periodontal problems due to excessive oc-clusai forces, or irritation of the tongue during speechand mastication."*'' In cases 2 and 3, an occlusai ad-justment by grinding the palatal projection of thetaloned tooth was performed to eliminate the prema-ture contact.

The treatment of talon cusp implicates careful clini-cal decision. The aid of radiographs is essential to as-sess whether the accessory cusp contains or is devoidof a pulp horn. However, radiographie tracing of thepulpal configuration inside the talon cusp has inherentdifficulties because the eusp is superimposed over theaffected tooth crown.'^ However, in case 5 the pulpextensions inside the talon cusps were radiographi-cally evident. Gungor et aF reported a case of hilat-eral talon eusps on primary maxillary central incisorswhose histologie evaluation revealed the existence ofpulpal tissue in the anomalous cusps. Thus, a previousradiographie study must have been performed beforethe removal of the cusp to avoid the pulp exposurethat would require endodontie treatment.^

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27. Gungor HC, Altay N, Kaymaz FF. Pulpal tissue in bilateraltalon cusps of primary central incisors: Report of a case.Oral SuiB Oral Med Oral Pathol Orai Radiol Endod 2000;89:231-235,

Quintessence International 277

Proceedings of the InternationalConference on Dentin/Pulp

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the function of pulp and dentin• Immunobiology of pulpal/periapical disease• Bioengineering for dentin regeneration• Resin hybridization in the dentin/pulp complex

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