Article Type : Case Report
Authors : Shunmugavelu K
Keywords : mesiodens, complex odontome, macrodontia, unerupted or impacted teeth, and peg shaped maxillary incisor, and dens invaginatus
Talon's cusp is a tooth
defect that protrudes from the cingulum or cementoenamel junction of the
maxillary or mandibular anterior teeth. A cusp is a morphologically
well-defined projection from the lingual/palatal surface of a main or permanent
anterior tooth that extends at least half the distance from the cementoenamel
junction to the incisal tip [1]. A talon cusp is an accessory cusp-like
anomalous feature that projects from the cingulum area or cementoenamel
junction and stretches at least half the distance to the incisal edge of the
maxillary or mandibular anterior teeth in both primary and permanent dentition.
The cusp is made up of regular enamel, dentin, and various extensions of pulp
tissue, but due to its superimposition on the main pulp chamber, its structure
is difficult to ascertain [2]. Regular enamel and dentine, and differing
degrees of pulp tissue, make up the talon cusp. Males and females may have it
unilaterally or bilaterally. Mitchell was the first to describe a talon cusp on
a woman's upper central incisor as "a mechanism of horn-like form curving
from the base downwards to the cutting edge" in 1892. Mellor and Ripa
coined the word "talon" cusp in 1970 to describe its shape, which
resembles an eagle's talon. Talon cusp affects only a limited proportion of the
population, with figures varying from less than 1% to around 8%. This effect
was later called a talon cusp by Ripa and Mellor because of its similarity to
an eagle's talon [3]. The definition for this condition in the anterior teeth is
not well described in the literature, which uses terms like talon cusp,
accentuated cingulum (when it impacts the lingual or palatal surface), and dens
evaginatus to explain it (the term that is usually used when it is present in
the posterior teeth). The verrucose protuberance on the occlusal surface of the
damaged teeth in dens evaginatus may be made of enamel, enamel and dentine, or
enamel, dentine, and a slight extension of the pulp tissue. The purpose of this
article is to give a comprehensive knowledge on talon cusps based on recent
literature.
Talon's cusp is a tooth
defect that protrudes from the cingulum or cementoenamel junction of the
maxillary or mandibular anterior teeth. A cusp is a morphologically
well-defined projection from the lingual/palatal surface of a main or permanent
anterior tooth that extends at least half the distance from the cementoenamel
junction to the incisal tip [1]. A talon cusp is an accessory cusp-like
anomalous feature that projects from the cingulum area or cementoenamel
junction and stretches at least half the distance to the incisal edge of the
maxillary or mandibular anterior teeth in both primary and permanent dentition.
The cusp is made up of regular enamel, dentin, and various extensions of pulp
tissue, but due to its superimposition on the main pulp chamber, its structure
is difficult to ascertain [2]. Regular enamel and dentine, and differing
degrees of pulp tissue, make up the talon cusp. Males and females may have it
unilaterally or bilaterally. Mitchell was the first to describe a talon cusp on
a woman's upper central incisor as "a mechanism of horn-like form curving
from the base downwards to the cutting edge" in 1892. Mellor and Ripa
coined the word "talon" cusp in 1970 to describe its shape, which
resembles an eagle's talon. Talon cusp affects only a limited proportion of the
population, with figures varying from less than 1% to around 8%. This effect
was later called a talon cusp by Ripa and Mellor because of its similarity to
an eagle's talon [3]. The definition for this condition in the anterior teeth is
not well described in the literature, which uses terms like talon cusp,
accentuated cingulum (when it impacts the lingual or palatal surface), and dens
evaginatus to explain it (the term that is usually used when it is present in
the posterior teeth). The verrucose protuberance on the occlusal surface of the
damaged teeth in dens evaginatus may be made of enamel, enamel and dentine, or
enamel, dentine, and a slight extension of the pulp tissue. The purpose of this
article is to give a comprehensive knowledge on talon cusps based on recent
literature.
While the precise cause
is unclear, it is believed to be a multifactorial etiology involving a mixture
of environmental and genetic factors. Outfolding of the inner enamel epithelial
cells, as well as a temporary focal hyperplasia of the mesenchymal dental
papilla organ or hyperactivity of the dental lamina, was thought to cause it
during the morphodifferentiation stage of tooth growth. A significant genetic
impact has been proposed by the presence of talon cusp in immediate family
members. Talon cusp may be seen alone or in combination with other dental
abnormalities including mesiodens, complex odontome, macrodontia, unerupted or
impacted teeth, and peg shaped maxillary incisor, and dens invaginatus. The
etiology of the talon cusp's formation is uncertain. However, it has been
proposed that a mixture of genetic and environmental causes, as well as the
hyperactivity of the dental lamina during early odontogenesis, play a part.
SturgeWeber syndrome (encephalotrigeminal angiomatosis), RubinsteinTaybi
syndrome, Mohr syndrome (orofacial digital II), incontinentia pigmenti
achromians syndrome, Ellis van Creveld syndrome, Alagille's syndrome, have all
been linked to it. Patients with Mohr syndrome, Sturge–Weber syndrome,
Rubinstein–Taybi syndrome, incontinentia pigmenti achromians, or Ellis–van
Creveld syndrome have also been reported to have talon cusps [4]. A
multifactorial etiology affecting both genetic and environmental influences is
strongly supported [5]. The morphologic stages and five physiologic processes
of tooth growth are classified into six morphologic stages and five physiologic
processes. Any anomalies in these stages/processes of tooth production will
lead to unexpected outcomes. Anomalies such as talon cusps, fusion, mesiodens,
dens invaginatus, peg laterals, and mulberry molars may result from
morphodifferentiation disruptions [6].
Talon cusp affects both
sexes and can be unilateral or bilateral in primary and permanent incisors. According
to study, 75 percent of talon cusps are found in the permanent dentition, while
25 percent are found in the primary dentition. Males have a greater level of
incidence than females. The maxilla is affected in 92% of cases, while the
mandible is affected in 8% of cases. In the main dentition, only central
incisors are involved, and the maxillary lateral incisor (67%) is the most
frequently impacted in the permanent dentition, followed by the central incisor
(24%) and canine (3%). Talon cusps come in a variety of shapes, sizes,
structures, locations, and origins. The prevalence has been stated to be 0.06
percent in Mexicans, 7.7 percent in northern Indians, and 1.2 percent in
Turkish dental patients. Chinese5 and Arabs have been shown to have talon cusps
in very large numbers [7]. According to a study of the literature, 25% of cases
are in the main dentition and 75% are in the permanent dentition [8,9]. The
cusp can be unilateral or bilateral, with a preference for the maxilla over the
mandible, and males have a higher frequency than females [10,11]. The most
often affected teeth are the maxillary lateral incisors in the permanent
dentition and the maxillary central incisors in the main dentition.
Hattab and colleagues
suggested a classification scheme for these irregular cusps based on their
degree of development and extension [12]:
Type I is a "true
talon," a morphologically well-delineated cusp that projects at least half
way from the cemento-enamel junction to the incisal edge. Type II is a
"semi talon," a morphologically well-delineated cusp that projects at
least half way from the cemento-enamel junction to the incisal edge.length of 1
mm or more but extends less than half the distance between the cementoenamel
junction and the incisal tip. The additional cusp in Type IIIis called a
"trace talon” since it is inflated and conspicuous, stretches less than
half way from the cemento-enamel junction to the incisal tip. A
"trace-talon," or expanded and prominent cingulum, is Type III.
Both sexes have been
confirmed to have talon cusps, which may be unilateral or bilateral. According
to previous accounts of talon cusps in the main dentition, the cusps are all
found on the maxillary central incisors. If the phenomenon is unilateral, it
would be more on the left side. There have been many reported clinical cases of
predominantly facial talon cusps, 75 % of which were found in permanent
dentition, including the latest study [13]. The palatal or lingual surfaces of
the anterior teeth normally have talon cusps. Vertical cristae (rugae
adamantineae) on the facial side of the teeth are an unusual variation often
used on the maxillary incisor [14]. A ridge of enamel that crosses the middle
of the vestibular surface of the tooth in a cervical-incisal direction, as in
the case mentioned in this article, is a distinguishing feature of Rugae
adamantineae. If the appearance of a talon cusp is related to issues like
impaired esthetics, occlusal intervention, tooth displacement, caries, periodontal
complications, or inflammation of the soft tissues during speech or
mastication, a talon cusp is not always an indicator for dental care. Based on
the size and form of the infected tooth, as well as the complications created
by the swollen cusp, the clinical treatment of this anomaly can vary greatly
(15–18). A talon cusp is normally asymptomatic, and it's often discovered by
chance during a routine dental exam. Where a talon cusp is symptomatic, it
normally causes issues with occlusion, voice, and appearance. Caries
susceptibility, occlusal intervention, and impaired esthetics are the most
common issues associated with a talon cusp. Conservative recovery approaches
should be used under the constraints of these issues. In such cases, a
comprehensive clinical and radiographic review is needed for effective
diagnosis and treatment planning. Talon cusps can cause issues such as
compromised esthetics and occlusal interference, which can result in accidental
cusp fracture, displacement of the affected tooth, caries developmental
grooves, food stagnation, tongue and lip irritation, speech problems, dental
sensitivity, breastfeeding issues, temporomandibular joint pain, and
periodontal problems due to excessive occlusion. The cosmetic, diagnostic,
functional, and pathological problems of talon cusp are all present. A tooth
with a broad talon cusp has an unattractive look [13-17]. If the talon cusp is
not fully erupted, it can appear on radiograph as a compound odontome or a
supernumerary tooth, contributing to a misdiagnosis. Occlusal interference,
tooth displacement, lip and tongue trauma, and voice disorders are also
examples of functional issues. Carious involvement in deep grooves causes
periapical pathology, and is a pathological complication. Traumatic occlusion,
accidental cusp fracturing, and even tooth displacement may all be caused by
irregular occlusal forces. Pulp toxicity and periapical pathology may result
from extreme attrition of these cusps.
A talon cusp occurs
radiographically as a “V”-shaped radiopaque structure. A radiopaque
"V"-shaped form is superimposed on a regular picture of a tooth's
crown. The shape and size of the cusp, as well as the angle of the radiograph,
will alter this appearance. It normally occurs on radiographs as true talon or
semitalon, or tuberclelike, as in trace talon, arising from the cervical third
of the root and superimposed over the crown of the tooth. In mandibular cases,
the point of the ‘V' is reversed. The shape and scale of the cusp, as well as
the angle at which the radiograph is taken, affect the appearance. Enamel,
dentine, and varying quantities of pulp tissue make up this structure. Because
of its superimposition over the main pulp chamber, determining the degree of
pulp extension into the cusp is challenging. Big talon cusps, it has been
proposed, are more likely to contain pulp tissue [19].
Photographs are
insufficient to explain the intricate morphology of the crown of such an
anomaly due to the two-dimensional limitations of radiographs. However, due to
the advancement of cone-beam computed tomography (CBCT), successful diagnosis
and care are now possible. The use of CBCT has become more popular in a variety
of dental specialties. CBCT was created with the aim of producing an undistorted
three-dimensional (3-D) recreation of the maxillofacial skeleton as well as
three-dimensional photographs of the teeth and their underlying tissues. 13
CBCT scans are useful for learning about dental pathology and planning care.
Depending on the individual appearance and
complexities, talon cusp management may be traditional or progressive. Since
small talon cusps are asymptomatic, there is no need for therapy. Easy
prophylactic steps such as fissure sealing or composite repair should be used in
situations where deep developmental grooves are present. To minimize exposure
and promote reparative dentine production in the case of occlusal interference,
the bulk of the cusp is progressively and regularly diminished with topical
fluoride treatment. In certain cases, a complete reduction of the cusp is
needed, followed by root canal operation [20]. No treatment, sequential
grinding, pit and fissure sealants, pulp therapy, restorative treatment,
absolute crown coverage, and replacement of the infected tooth are all options
for treating talon cusps. Since a talon cusp on an unerupted tooth may be
misinterpreted radiographically as a supernumerary tooth, compound odontoma, or
dens in dente, a definitive diagnosis of a talon cusp cannot be made based solely
on radiographic results [19-22]. Just a few cases of facial talon cusps treated
fully were documented in the literature. After removing a mandibular left
central incisor with a talon cusp for esthetic purposes, McNamara and
colleagues used orthodontics to close a space. With a maxillary right permanent
central incisor, de Sousa and colleagues performed an esthetic reconstruction
during root canal surgery. Gradual cuspal grinding and resin-based composite
reconstruction of a facial talon cusp on a maxillary permanent left central
incisor were used in a case recorded by Glavina and Skrinjaric. Another case
recorded by Kulkarni and colleagues included the reduction of a talon cusp
every 45 days, followed by the application of fluoride varnish for 9 months. A
talon cusp is made up of regular enamel and dentin, with the possibility of
pulpal extension. Place, form, scale, function, and number are all clinical
variants of the talon cusp. Based on whether or not pulpal extensions are
present, different care regimens have been used to cure talon cusps. Pulpotomy
may be achieved using calcium hydroxide or mineral trioxide aggregate content
if there is pulpal expansion [23]. No pulpal extension was found in this
situation, and these materials were not used [24]. Small talon cusps are
normally asymptomatic, and there is no need for therapy. Wide talon cusps, as
in our situation, may, however, create issues for the patient. The dentist's
diagnosis and recovery preparation are also complicated [25]. Treatment for
talon cusps is based on whether the cusp is similar to the pulp or contains
pulp which requires a thorough clinical review [26].
Talon cusp is a serious
dental anomaly, since it can make diagnosis and recovery preparation difficult
for clinicians. The scale, presenting problems, and patient cooperation both
affect how talon cusp is handled and treated. The aim of early talon cusp
diagnosis is to prevent local problems including caries, periodontal disease,
and malocclusion. Talon cusp may occur in the presence of other systemic
diseases or dental abnormalities. Clinicians must be mindful of developmental
anomalies, their differences, health conditions, and medical options for their
management at all times. Selective cusp is one of the management choices.
Depending on the severity of the complications present, various management
options include selective cuspal grinding of accessory cusps and application of
fluoride as a desensitizing agent, complete reduction of cusp followed by root
canal treatment, and complete reduction of cusp followed by root canal
treatment.