management of the developing dentition part 1

dr Maher FOUDA
Faculty of Dentistry
Mansoura Egypt
Professor of orthodontics
Part 1
Management of the
developing dentition

A number of developmental anomalies can affect
both the primary and permanent
dentitions. These include variation in the number
of teeth or their individual morphology,
the position they attain within the dental arches
and the composition of their constituent
hard tissues.

The aetiological basis of these abnormalities can
be genetic, environmental
or multifactorial, but they can all impact upon the
developing occlusion, either directly
or indirectly.

.
Tthe aetiology and management of
these anomalies is presented in
relation to the developing dentition

Early loss of primary teeth
The early loss of primary teeth is usually the
result of extraction due to caries or trauma
and can have implications for the developing
occlusion; in particular, future space distribution
and symmetry within the affected dental arch.
early loss of primary
teeth

The degree of space loss, crowding
and potential occlusal disruption can be
influenced by a number of factors:
• Age – the earlier the primary tooth is lost, the
more potential for crowding will
exist;
• Existing space requirements – the more
inherent crowding already present within the
dental arch, the more potential space loss will
occur as a result of early primary tooth
loss; and

• Tooth type – the position of the affected tooth within the dental arch will also
influence
subsequent space distribution:
• Primary incisors rarely affect space in the permanent dentition unless they are lost
very early as a result of trauma or early resorption secondary to crowding;
• Primary canines are not often lost prematurely; but when they are, this can lead
to a centreline shift towards the affected side in unilateral cases, particularly in a
crowded dentition
The lower centreline has shifted to
the right following early loss of the LRC.

• Primary first molars can also produce a
centreline shift when lost prematurely and
unilaterally. In the presence of crowding, early
loss of these teeth can also result
in space loss through forwards movement of the
buccal segments and accentuate
premolar crowding; and

• Primary second molars less commonly affect the centreline when lost prematurely,
but they do influence the position of the first permanent molar. Early loss can
result in forwards bodily movement of this tooth if it is unerupted, or tipping
and rotation if it is erupted. This can result in space loss and premolar crowding
, the severity reflecting the amount of forwards movement that has
occurred.
Crowding of maxillary
second premolars as a result of early
loss of the second primary molars. The
UL5 remains impacted in the palate
whilst the UR5 has erupted palatally.

The timing of primary tooth extraction can also
influence the eruption rate of permanent
successors. Very early loss of primary teeth can
delay successional tooth eruption, whilst
later extraction can have the opposite effect.

Balancing and compensating extractions
Balancing and compensating extraction of
primary teeth aims to preserve arch symmetry
and occlusal relationships by extracting
contralateral and opposing teeth, respectively to
those requiring enforced extraction (Ball, 1993).

• A balancing extraction is the removal of a
tooth from the opposite side of the same
dental arch to preserve the centreline by
maintaining arch symmetry; and
• A compensating extraction is the removal of a
tooth from the opposing quadrant to
maintain the buccal occlusion by allowing
molar teeth to drift forwards in unison.

The decision to carry out a balancing or
compensating extraction will depend upon a
number of factors . However, before the elective
extraction
of any primary tooth is instituted, a radiographic
screen should be carried out to check
for the presence, position and normal formation
of the developing permanent dentition.

Any other primary teeth of questionable prognosis
should also be considered as candidates
for balancing or compensating extraction,
particularly if general anaesthesia is
required. It can be more difficult to justify these
extractions if local anaesthesia is used
for the elective extraction of a single symptomatic
tooth and cooperation for further
extractions may be poor.
Tooth 46 was symptomatic and was extracted. Significant distal
arch crowding was evident with likely future impaction of the lower
second and third molars. Extraction of the 16 was also recommended
as a compensating extraction as many primary teeth remain and
comprehensive fixed appliance treatment may not commence for
several years.
Compensating extraction

Compromised first permanent molars: an orthodontic
perspective
DC-V Ong, JE Bleakley
Australian Dental Journal 2010; 55: 2–14
Balancing extraction

Where is the evidence 1? Which primary teeth require balancing and
compensating extractions?
Current guidelines for balancing (balance-enforced) and compensating
(compensate-enforced) extractions of primary teeth are available from the Royal
College of Surgeons of England (Rock, 2002). It is acknowledged that although
supported by the best available data where possible, the lack of research in this
area means that these guidelines are based primarily upon clinical opinion.
• It is not necessary to balance or compensate the loss of a primary incisor from
either dental arch;

• The premature and unilateral loss of a
primary canine is often associated with
a centreline shift and a balancing extraction
can help to preserve the centreline;
however, compensating extractions are not
required in this situation;

• The premature and unilateral loss of a
first primary molar can also induce a
centreline shift, particularly in a crowded
arch and a balancing extraction may
be required to preserve the centreline;

• Second primary molars do not require
balancing extractions; however, early
extraction may allow significant forwards
movement and tilting of the adjacent
first permanent molar. Therefore, consideration
should be given to fitting
a space maintainer; and
• In general, compensating extractions for
primary first and second molars are
not necessary (unless some of these teeth are
restored and the child is having
a general anaesthetic).

Space maintenance
A space maintainer is a removable or fixed orthodontic appliance that preserves space
within the dental arches . These appliances are most commonly used in the
mixed dentition to prevent forwards drift of the first permanent molars following early
loss of primary second molar teeth, or to maintain space and serve as a prosthesis in the
labial segment after traumatic loss of permanent incisors.
Lower fixed space maintainers to preserve the
arch length (left panels);
preservation of labial segment position with a
removable retainer (upper right and middle
panels); and restoration of a LLE with a
stainless steel crown to prevent space loss
(lower right
panel).

• In an occlusion with only minor space
requirements where any further space loss
would make non-extraction treatment difficult
and increase in the need for methods
of space generation, such as extractions or
headgear; and

• In an occlusion with more severe space requirements where any further space loss
would result in more than a single tooth unit of space being required.
It should always be remembered that a tooth is the ideal space maintainer and every
effort should be made to preserve primary teeth until the time of their natural exfoliation.
Lower fixed space maintainers to preserve the arch length (left
panels);
preservation of labial segment position with a removable retainer
(upper right and middle
panels); and restoration of a LLE with a stainless steel crown to
prevent space loss (lower right
panel).

If a space maintainer is to be used it should be in
a mouth with good
oral hygiene and, ideally, a low risk of further
caries. Unfortunately, cases requiring elective
tooth extraction due to dental caries are often
the least suitable for long-term space
maintenance.

Prolonged retention of primary teeth
Considerable variation can exist in the timing of primary
tooth exfoliation and the subsequent
eruption of permanent successors. The presence of
marked asymmetry in the
retention of primary teeth should be investigated
radiographically .
Marked asymmetric eruption of the maxillary incisor dentition in this 9-year-old
boy should arise suspicions. Radiographic examination reveals the presence of two
supernumerary teeth in the anterior maxilla (arrows in middle panel; arrowheads in right
panel), which have prevented eruption of the UR1 and UR2.

Prolonged retention of primary teeth
The UR3 is erupting
buccally having failed to resorb the primary
canine.
It is not uncommon to find a permanent
successor failing to adequately resorb the
roots of an overlying primary tooth during its
eruption .

The patient should be
encouraged to exfoliate these retained primary teeth
themselves and if this is not possible,
they should be extracted under local anaesthetic.
Sometimes the permanent teeth
can erupt into a displaced position within the arch, which
occasionally can manifest as
a significant problem .
Abnormal retention of primary
incisors. The permanent incisors
have failed to
resorb their primary predecessors
and have erupted palatally (upper
left panel) and lingually in
the case of the LR2 (lower left
panel). The right panels show the
crowded dental arches of a
10-year-old boy affected by
significant palatal and lingual
eruption of the permanent incisors
and retention of the primary
incisors.

Crowding, an ectopic position, impaction or
agenesis of the permanent successor can
also lead to prolonged retention of the overlying
primary tooth. Commonly encountered
scenarios include retention of a primary central
incisor or canine due to impaction of the
permanent successor; and retention of a primary
second molar due to agenesis of the
second premolar.

If the permanent successor is present,
management is dictated primarily by the
amount of space available within the dental
arch and the position of the unerupted
permanent tooth.
• If space is available, extraction of the primary
tooth alone can often lead to successful
eruption if the permanent tooth is in a
favourable position;
Left: Photograph of frontal view of
primary right upper central incisor.
Right: Radiographic view showing
root canal filling
Photograph of frontal view showing
deviation in eruption path of
permanent right upper central
incisor. Right: Radiographic view
showing persistence of zinc oxide
eugenol particles and deviation in
eruption path of permanent right
upper central incisor.
Photograph of frontal
view after 7 months,
showing eruption of
permanent right upper
central incisor with shift
in direction of eruption

Maxillary view showing the over-retained right primary canine.
• If space is at a premium, maintenance may be
required following removal of the
primary tooth, or alternatively space will need to
be created;

Mandibular view showing the over-retained right primary
canine, first, and second molar.
• If the position is less favourable, exposure of
the permanent tooth (with or without
the application of orthodontic traction) may
also be required; and

Midline was on and the position of maxillary ca-nines was
buccal
• Extraction of the permanent tooth may be
considered if the position is poor, either
in isolation or in combination with other teeth as part
of an orthodontic treatment
plan. The decision to extract will also be influenced
by the type of tooth under
consideration.

Radiographic evaluation showed unerupted max-illary left
second premolar, canine, maxillary and mandibu-lar third
molars.
If the permanent successor is absent, the long-
term prognosis for most of these primary
teeth will be poor and they will either be lost
naturally or ultimately require extraction.
However, they can often act as useful
maintainers of arch space or alveolar bone in the
shorter term and can often be left in situ until
definitive treatment.
A clinical photograph of a sectional fixed-
orthodonticappliance to correct a tipped
mandibular molar

Retained second primary molars
The second primary molar is often retained due
to agenesis of the second premolar. If
this is the case, several treatment options
should be considered:
• Extraction and space closure;
• Extraction and prosthetic replacement; or
• Retention of the second primary molar.
Consequences of Retention of Primary Second Molars
Infra-Occlusion

Treatment planning will depend upon future
space requirements for the correction of
any underlying malocclusion and the long-
term prognosis of the second primary molar.
Clinical and radiographic examination of the
crown, root and associated alveolar bone
will give a useful indication of this .
Lower left second primary molar showing signs of early infra-occlusion.
An early reliable indicator of ankylosis is the presence of an angular
alveolar defect between an ankylosed tooth and the adjacent teeth with
normal eruptive mechanisms
A 74-year-old with an asymptomatic lower left second primary molar.
Had such a tooth been extracted and replaced in adolescence or early
adulthood, the restoration would almost certainly have required
replacement on more than one occasion over the ensuing five or six
decades

Any of the following features, either alone
or in combination, will demonstrate a
potentially poor prognosis:
Retained lower second
primary molars in association with agenesis
of the second premolars. In the upper
radiograph, both the lower Es have a
good long-term prognosis. In the lower
radiograph, extensive root resorption means
a poor prognosis for both the retained
lower Es.
• Periapical or interradicular pathology;
• Ankylosis;
• Infraocclusion; and
• Gingival recession.
• Caries or restoration;
• Root resorption;
• Bone resorption;

Second primary molars can have an excellent
long-term prognosis if they are in good
condition and will match the lifespan of many
prostheses. Indeed, if they survive to 20
years of age, continued long-term function can
be anticipated .
(a and b) Missing mandibular second premolars with ankylosed and infra-occluded
deciduous second molars in a distal malposition; (c to e) a ceramic onlay to close the
residual mesial space
Patient with primary second
molar that reduced distally to
obtain better occlusal
relationship

Retained and infra-
occluded lower right
primary second molar. a)
Occlusal view, b) buccal
view, c) radiograph
showing favourable root
length and form and
absence of pathology. d)
Chamfer preparation for
composite onlay. Indirect
composite onlay e)
buccal view, f) occlusal
view
Ankylosis and infraocclusion
A tooth becomes ankylosed when the periodontal ligament is lost and direct fusion
occurs between root dentine and the surrounding alveolar bone. Ankylosis is relatively
common, occurring in up to 9% of children and most often affecting the primary molars
An OPG radiograph of a severely
infraoccluded mandibular right second molar
in a five-year old

A number of factors are thought to
contribute:
• Genetic predisposition;
• Failure of normal resorption by the
permanent successor;
Agenesis of the permanent
successor;
• Trauma; and
• Infection.
•
(A) intraoral photo. Infraocclusion of
the maxillary left second primary
molar being covered by the
surrounding tissues. (B)Panoramic
radiograph. Submerged maxillary left
second primary molar with underlying
permanent successors. (C-E) CBCT
image, horizontal, coronal andsagittal
view. Upper left second premolar tooth
germ position mesiopalatally

A consequence of ankylosis can be the apparent
‘submergence’ or infraocclusion of the
tooth relative to the occlusal plane . This occurs
in the growing child because
alveolar bone and occlusal height increase with
development, whilst the position of the
ankylosed tooth remains fixed.
Infraocclusion of the ULE in association with
congenital absence of the UL5.

• In the presence of a permanent successor
and minimal infraocclusion, the ankylosed
tooth can usually be left under observation
to exfoliate naturally;
Summary of the 4 treatment procedures to distalize and maintain the
mandibular first permanent molar: (a) leveling arch wire; (b) open coil
with split crimpable stops; (c) segmental space maintainer; and (d)
lingual arch. Note the uprighting of the second premolar
An OPG radiograph of a nine-year-old boy with
infraoccluded deciduous molars and the presence of
permanent successors

• If the infraocclusion becomes greater this
can lead to displacement and tipping of
adjacent teeth, and overeruption of opposing
teeth. In these circumstances, consideration
should be given to either restoring the
vertical dimension or extracting the
affected tooth.
severely intruded maxillary left second deciduous molar and
inclination of the adjacent tooth.
2 impacted maxillary premolars
extraction of the ankylosed maxillary left second deciduous molar,
maxillary right second deciduous molar, and the impacted and
ankylosed maxillary second premolars.
moving the posterior teeth mesially

Direct resin composite restorations
can be effective for the transitional
restoration of infraoccluded
second primary molars; and
A left mandibular second primary molar with severe infra-
occlusion.B, right mandibular second primary molar with
moderate infra-occlusion.
the retained infra-occluded primary
molars with agenesis of the
permanent successors
Diagnostic wax-up of
the case.
Buccal and lingual shell of composite prior to
placement of a circumferential matrix for
subsequent incremental layering techniques
incremental layering of composite
with a circumferential matrix in
place
Buccal shell of composite
A, Occlusal view of the final restoration on the right mandibular second
primary molar prior to final polish.B, Lateral view of the final restoration on
the right mandibular second primary molar prior to final polish

• In the absence of a permanent successor, a decision will need to be made regarding
long-term management of the missing tooth within the occlusion. However, the presence
of ankylosis or infraocclusion in a growing patient will often make extraction
more likely.
Lower left second primary molar
showing signs of early infra-
occlusion. An early reliable indicator
of ankylosis is the presence of an
angular alveolar defect between an
ankylosed tooth and the adjacent
teeth with normal eruptive
mechanisms
slight infraocclusion moderate infraocclusion severe infraocclusion
an altered occlusal plane due to
infraocclusion
an altered occlusal plane due
to infraocclusion

Where is the evidence ? Management of the ankylosed maxillary
permanent incisor
The maxillary incisors are vulnerable to trauma and the consequences of a
significant
trauma, such as intrusion or avulsion, can be loss of vitality, replacement
resorption and ankylosis.
maxillary right central incisor in
infraversion and ankylosed
The patient was then submitted to surgery. Two vertical
vestibular relaxing incisions were performed distal to the upper
canines, and a horizontal incision was performed superiorly, in
the alveolar mucosa. After the opening of the flap, vestibular
periosteum detachment was performed.
The mucosa and the periosteum in the palatal region were
maintained intact in order to preserve blood irrigation. The
osteotomy was performed with drill and chisel mesially,
distally, and apically to the root of tooth 11. A chisel was
used to release the bone fragment, which remained
connected only by the palatal periosteum. After that, the
vestibular periosteum and the flapwere repositioned and the
suture was performed.

In a growing child, this can lead to progressive
infraocclusion,
which can be unsightly.
Ankylosed and
infraoccluded UL1, which had
previously been avulsed and
replanted.

Management will depend upon a number of
factors, not least the age of the child, the
severity of any infraocclusion and any
underlying malocclusion; but in essence will
involve the following:
• Simple follow up with composite build up if
necessary;
the consequences ofinfraocclusion a composite build-up on an infraoccluded
mandibular molar without a permanent
successor

• Surgical dislodgement (with or without a
local osteotomy) and repositioning
(manual, orthodontic or distraction
osteogenesis);
.
• Removal and prosthetic replacement
(occasionally decoronation is carried out
in an adolescent to preserve alveolar bone
prior to an implant);
a segmental osteotomy was performed with an autogenous
bone graft in a single-stage surgery to align and level the
ankylosed teeth. The dento-osseous segment was success-
fully repositioned with satisfactory periodontal results.

• Removal followed by autotransplantation of a premolar; and
• Removal followed by orthodontic space closure.
A recent Cochrane review has failed to identify any trials to support clinical
decision-making for treatment of ankylosed permanent incisors. It is recommended
that clinicians base their treatment planning on experience and patient
preference
Then a single-tooth osteotomy was performed in 1 surgical stage to allow for
inferior repositioning of the tooth and bone. The ankylosed tooth was successfully
leveled in the maxillary arch with a harmonic gingival margin.

, ankylosis is most commonly seen in association with maxillary
central incisors as a result of trauma. In particular, intrusion and avulsion injuries can lead
to replacement resorption, ankylosis and infraocclusion. The management of
these teeth will depend upon a number of factors, but the worst affected will ultimately
require extraction and either space closure or restorative replacement
Ankylosed permanent maxillary incisors
In the permanent dentition
a patient with class I crowded malocclusion and labially
displaced andintruded traumatized maxillary incisors. The
protruded traumatized incisors were successfullybrought to
an acceptable position with acceptable gingival esthetics
through the use of simpleorthodontic traction combined with
first-premolar extraction.

Selective tooth agenesis
Selective tooth agenesis (STHAG) is a failure of one
or more teeth to develop and is a
relatively common anomaly in human populations.
• Nonsyndromic or familial STHAG occurs as an
isolated trait; whereas
• Syndromic STHAG occurs with accompanying
genetic disease.
Nonsyndromic STHAG. In the upper case there is incisor–premolar STHAG with
UR2, UL2, LL5, LR5 and the lower third molars absent. In the middle case there is hypodontia,
with UR5, UR4, UL4, UL5, LR5, LL5 and all third molars absent. In the lower case there is
oligodontia, with UR5, UR4, UR2, UL2, UL5, LL4, LL1, LR4, LR5 and all third molars absent.

Hypodontia is also used as a generic term to
describe developmental tooth absence, but
the definition is actually more specific :
• Hypodontia refers to an absence of one to six teeth,
excluding third molars;
• Oligodontia refers to an absence of more than six
teeth, excluding third molars; and
• Anodontia refers to a complete absence of teeth in
one or both dentitions.
Nonsyndromic STHAG. In the upper case there is incisor–premolar STHAG with
UR2, UL2, LL5, LR5 and the lower third molars absent. In the middle case there is hypodontia,
with UR5, UR4, UL4, UL5, LR5, LL5 and all third molars absent. In the lower case there is
oligodontia, with UR5, UR4, UR2, UL2, UL5, LL4, LL1, LR4, LR5 and all third molars absent.

Nonsyndromic selective tooth agenesis
Nonsyndromic STHAG can either appear sporadically
within a member of a family or be
inherited. Inherited forms can follow autosomal
dominant, autosomal recessive
or autosomal sex-linked patterns of inheritance, with
considerable variation in both
penetrance and expressivity. These familial forms
represent the most common types of
developmental tooth absence, with some attempts now
being made to classify them
according to their genetic basis .

Classification of nonsyndromic selective tooth
agenesis (STHAG)

However, whilst the genetics of STHAG are
still relatively poorly understood, there are a number of
characteristic clinical features:
• Localized incisor–premolar STHAG affects only one or
a few of these teeth and is the
most common form of developmental tooth absence,
being seen in around 8% of
Caucasians ; and
• Oligodontia is the least common, occurring
in only around 0.25% of Caucasians and
involving all classes of teeth, but particularly
the molar dentition.
the bilateral retained crowns of deciduous maxillary canines with the complete absence
of the permanent once and mandibular third molars

Within these clinical entities, certain teeth fail to
develop more often than others:
• Third permanent molars are the most commonly
absent tooth;
• These are followed by mandibular second
premolars and maxillary lateral incisors
(around 2%) and mandibular central incisors
(0.2%) in Caucasians.

• Collectively, teeth at the end of each series seem to be the most
vulnerable to agenesis,
including: third molars (up to 30%), mandibular second premolars and
maxillary
lateral incisors (both around 2% in Caucasians). This might
be related to the timing of their development, being the last to form
within each
family and therefore vulnerable to falling below the developmental
threshold required
for normal development ; and
• Agenesis of canines, first and second molars, is rare in isolation .
Intraoral photograph showing retained deciduous maxillary right and
left canines and mandibular both right and left central incisors
Agenesis of maxillary permanent first molars

Nonsyndromic STHAG can be associated with
other developmental anomalies affecting
the dentition, which provides evidence of a
genetic influence . However, a
multifactorial model has also been suggested,
with the phenotypic effect being related
to certain thresholds, themselves influenced by
both genetic and environmental factors
. Clearly, within this model, the mutation of a
major gene may be a significant
enough event to result in inherited tooth loss.
absence of tooth #32

Dental anomalies associated with hypodontia
and oligodontia

Syndromic selective tooth agenesis
STHAG is also seen in association with other recognizable structural defects or
abnormalities.
• One of the most common causes of syndromic STHAG is Down syndrome (OMIM
190685), which results from the presence of an extra copy of all or part of chromosome21;
• The ectodermal dysplasias are a heterogeneous group of conditions characterized
primarily by defective teeth, hair, nails and sweat glands. In
particular, the hypohydrotic X-linked recessive form (OMIM 305100) is associated with
oligodontia affecting both dentitions; and
A female patient presenting with several common features of hypodontia. Note the agenesis of the
maxillary lateral incisors andthe second premolars, the retained primary mandibular molars, the
generalised spacing, and the deep bite.

• Mutations in the homeobox gene MSX1 have also been
associated with a syndromic
condition demonstrating various combinations of orofacial
clefting and tooth agenesis
and with Witkop syndrome (OMIM 189500), a
form of ectodermal dysplasia . Thus, MSX1 represents a
candidate gene for both syndromic and nonsyndromic
STHAG, a feature shared with
a number of other genes .
Angle ClassI malocclusion and oligodontia due to 11 congenitallymissing permanent teeth in
combination with peg laterals,ankylosed deciduous molars, and taurodontism

Management of tooth agenesis
• Space closure; or
• Maintenance or opening of space, followed by
prosthetic replacement of the missing
tooth units.
In simple terms, the management of tooth
agenesis will involve either:
Management of unilateral maxillary lateral incisor absence with space
closing.; Canines and first premolars are mesialized bilaterally for
substitution of lateral incisors and canines, respectively; The
microdontic left lateral incisor is extracted and the spaces of missing
lateral incisors are closed bilaterally by mesialization of the posterior
segments
Management of bilateral maxillary lateral incisor absence with
space opening. Temporary crowns are placed on dental implants
bilaterally for substitution of lateral incisors;. Spaces are opened for
dental implants for substitution of missing lateral incisors, whereas
the space of missing right first molar is closed

Milder forms of incisor–premolar STHAG can
usually be managed within an orthodontic
treatment plan in consultation with either the
general dental practitioner or restorative
specialist and is usually carried out in the
permanent dentition . More
severe hypodontia or oligodontia requires more
complex multidisciplinary treatment and
is usually carried out within a specialist centre.
missing 41, 45, 31, 33

Supernumerary teeth
Supernumerary teeth are teeth present in addition to the
normal complement and can
occur within either dentition.
• In Caucasians, supernumerary teeth are seen more
commonly in the permanent dentition,
affecting around 4% of the population;
• In the primary dentition, the range is less than 1%; and
• In the permanent dentition, supernumerary teeth are twice as
common in males and
five times more common in the maxilla than in the mandible.

In common with the different forms of STHAG,
supernumerary teeth also occur either
as an isolated trait or as a manifestation of a
clinical syndrome , but they are
usually classified according to morphology and
location, and have different epidemiological
characteristics .
Panoramic radiograph of the patient. Note the absense of
eight teeth and the small dimension in maxilla

(a) conical shaped deciduous maxillary incisors. (b) Clinical photograph showing missing 55, 56, and 65.
(c) generalized spacing between teeth and note microdontia

Epidemiological characteristics of altered tooth number. In general, more
people are affected by tooth agenesis and they tend to have more teeth missing. Perhaps this
is why tooth agenesis is classified according to number and extra teeth are classified according
to morphology.

• Conical supernumeraries are small peg-shaped
teeth with normal root formation.
When located in the midline of the anterior
maxilla these teeth are known as mesiodens
, whereas in the maxillary molar region they are
known as paramolars
(buccal, lingual or interproximal to the second
and third molars) or distomolars (distal
to the third molar)
Conical supernumeraries. Mesiodens positioned in the anterior maxilla, either
vertically (left and middle) or horizontally (middle). Distomolar erupting behind the
UL8 (right).

Managing the mesiodens
The mesiodens is one of the most common forms of supernumerary tooth and
is often detected in the anterior maxilla as a chance radiographic finding. Most
investigations of mesiodens have been retrospective, but they have shown that
complications associated with the presence of these teeth seem to occur in
around 50% of patients and include impaction, displacement or rotation of the
permanent incisors, midline diastema, resorption of adjacent teeth, cystic
changes
or nasal eruption.
Mesiodens: A Case Report and Literature Review
Inter Ped Dent Open Acc J
1(3)- 2018.

Removal is indicated if they interfere with
the eruption, position or proposed orthodontic
movement of adjacent teeth, but
those that are asymptomatic should be left alone. The
potential
risks associated with leaving these teeth in situ, such
as follicular enlargement,
cystic formation and resorption of maxillary incisor
roots, would appear to be
small .
MESIODENS. A CASE
REPORT
Revista Facultad de
Odontología Universidad
de Antioquia - Vol. 28 N.o
1 - Segundo semestre,
2016

In addition, if the mesiodens subsequently erupts,
it can be removed with a relatively simple extraction
under local anaesthesia.
It would appear that long, thin mediodens situated
in parallel and between
the central incisors are those most likely to
spontaneously erupt .
Intra-oral view
showing erupted mesiodens and
congenitally missing teeth 13 and 23.
A midline supernumerary tooth or mesiodens is situated
between the unerupted maxillary central incisors .
Arrows indicate the position of the mesiodens which can
cause disturbances in eruption and adjacent tooth formation .

• Tuberculate supernumeraries are characterized
by a multicusped coronal morphology
and a lack of root development .
Extracted tuberculate supernumeraries and the effect
of these teeth on the
developing dentition.
Tuberculate supernumerary teeth and its management-a rare
case report
Journal of Dental Health, Oral Disorders & Therapy
eISSN: 2373-434

These teeth are usually found palatal to
the maxillary permanent incisors, often occur
in pairs and frequently prevent eruption
of the permanent incisors .
Erupted tuberculate supernumerary. The URA has been exfoliated and the
UR1 is unlikely to erupt whilst the supernumerary is in situ.

• Supplemental supernumeraries represent
the duplication of a tooth within a series
and can be difficult to differentiate from the
normal tooth . These teeth
are usually found at the end of a series and
can be seen in the incisor, premolar and
molar fields.
Supplemental UR2s.

They represent the most common
type of supernumerary found in the
primary dentition ; and
supplemental URB.

• Odontomes are developmental malformations
that contain both enamel and dentine
, and can be compound (containing many small
separate tooth-like structures
usually situated in the anterior jaw) or complex
(a large mass of disorganized
enamel and dentine usually situated in the
posterior jaw).
Complex odontome in the
posterior maxilla. Note vertical displacement
of the UL6.

Supernumerary teeth occur individually or in
groups and can be unilateral or bilateral.
These teeth are found most frequently in the
anterior maxilla, but are also seen in the
premolar and molar regions. In the permanent
dentition, the majority fail to erupt and
are asymptomatic, only being discovered during
routine radiographic screening.
Marked asymmetric eruption of the maxillary incisor dentition in this 9-year-old
boy should arise suspicions. Radiographic examination reveals the presence of two
supernumerary teeth in the anterior maxilla (arrows in middle panel; arrowheads in right
panel), which have prevented eruption of the UR1 and UR2.

However,
they can also cause dental
problems, which include:
• Failure of tooth eruption – the
presence of a supernumerary
can prevent the eruption
of a permanent tooth .
Conical supernumerary preventing eruption of the UL1.

In these circumstances, the supernumerary
should be removed and provided space is
available and the tooth is in a good
position, there is a high chance the impacted
tooth will erupt unaided. However,
exposure of the tooth is often undertaken at the
same time, particularly in older
children so orthodontic traction can be applied
to the tooth to mechanically erupt it
into the dental arch if it does not erupt
spontaneously ;
The impacted UL1 has been exposed, bonded with a gold chain and traction
applied using a removable appliance. Fixed appliances were subsequently used to detail the
permanent dentition.

• Crowding – supernumerary teeth can
contribute to dental crowding, either directly
as a result of eruption (particularly for
supplemental teeth) or indirectly by causing
displacement or rotation of adjacent erupted
teeth . These supernumerary
teeth will usually require extraction as part of a
definitive orthodontic treatment plan.
When extracting these teeth, care must be taken
to ensure the most poorly formed
is removed;
An erupted mesiodens causing crowding and displacement of the UL1.
The arrows point to the supernumerary teeth; note
that these are two supplemental dysmorphic teeth

• Spacing – supernumeraries can also produce
spacing between erupted teeth, particularly
a mesiodens producing a maxillary diastema
between the central incisors.
If orthodontic space closure is planned, these
supernumeraries will require
extraction; and

• Cystic formation – as with any unerupted tooth,
cystic formation can occur. Any
evidence of follicular enlargement or cystic
formation and these teeth should be
removed.
The OPG shows a multilobulated calcified tooth like
structure (supernumerary tooth) erupting at the midline (*),
and the relationship to included permanent and persistent
deciduous right central incisors. Note the difficult
interpreting of these two-dimensional images

Asymptomatic supernumerary teeth not
affecting the occlusal relationships of the
erupted dentition can be left in situ. These teeth
should be kept under periodic radiographic
review to ensure they are not damaging any
adjacent structures or undergoing
cystic change.
A: Panoramic radiograph showing the presence of supernumerary teeth. B: Linear CT
scan showing the localization of supernumerary teeth in the region of the second lower
left premolar. The image of the teeth was labeled for better visualization

Abnormalities of tooth size
Teeth either larger or smaller than the normal
population range for dimensions are usually
referred to as megadont or microdont,
respectively. These variations in tooth size can
affect either the crown or root in isolation, or the
whole tooth.
Isolated bilateral
macrodontia of the
mandibular
second premolars
with familial multiple
supernumerary teeth:
A case report
p e d i a t r i c d e n t a l j o
u r n a l x x x ( 2 0 1 7 ) 1 e4

• Megadontia affects around 1% of the
population and is most frequently seen in the
maxillary permanent incisors or mandibular
second premolars and is often
symmetrical.
Little is known about
the aetiology of tooth size variation but it is
almost certainly genetic.
Megadont UL1.

Extraction
of megadont teeth is often indicated, particularly
with maxillary central incisors,
because the aesthetics can be poor. Depending
upon the space requirements, either
macrodontia of the maxillary left central incisor
the lateral incisors can be approximated and
adjusted restoratively to look like central
incisors or space maintained for prosthetic
replacement; and

the lateral incisors can be approximated and
adjusted restoratively to look like central
incisors or space maintained for prosthetic
replacement; and
A truly megadont tooth can be
differentiated from a double tooth by
an absence of coronal notching and
presence of normal pulpal morphology.
Cone beam computed tomography (CBCT). The size
of the crown of the premolars exhibiting macrodontia
is larger than that of the molars in the dental arch

• Microdontia is seen in around 2.5% of the
population, can affect the whole dentition
or individual teeth and is often associated with
STHAG. The maxillary permanent
lateral incisor is one of the most common teeth
to be affected, often having a characteristic
peg-shaped crown morphology .
A microdont (peg-shaped)
UL2 seen in association with agenesis of
the UR2.

This has a causal association
with palatal impaction of the maxillary canines.
Whether a microdont maxillary lateral
incisor is retained or extracted depends not only on
the underlying malocclusion and
the need for extractions, but also on the shape and
form of this tooth and whether
it can ultimately be aesthetic and functionally viable.

If the tooth is to be retained,
the crown will require restorative build up to
improve aesthetics and symmetry, particularly
if it is unilateral. Space will often need to be
created to allow this, which
usually necessitates fixed appliances. If the
lateral incisor is extracted, space will also
need to be created if prosthetic replacement is
planned, as these teeth are usually
smaller than the space required for suitable
pontics.
patient with microdontia of the upper lateral incisors and
retention of the upper right central incisor

Abnormalities of tooth form
A number of anomalies associated with tooth
form have been described. These conditions
are generally rare, occurring with prevalence
below 5% in Caucasians and, with
the exception of double teeth, they generally
affect the permanent dentition more commonly
than the primary.
Dracula tooth: A very rare case report of peg-shaped
mandibular incisors
Peg-shaped maxillary incisor Peg-shaped mandibular incisors

• Double teeth can range from a slightly enlarged
tooth with minor coronal notching
to almost complete separation of two normally
formed teeth and are often associated
with megadontia. They include gemination
(developmental separation of a single
tooth germ) or fusion of adjacent tooth germs and
are most commonly seen in the
labial region of the mandibular primary dentition ,
but can also affect
permanent teeth.
Double incisor teeth in the primary dentition with variable
amounts of
coronal notching.

In the primary dentition, it is important to
establish whether a
double tooth is associated with tooth agenesis
because this can indicate possible tooth
absence affecting the permanent teeth.
fused second maxillary molar and a parulis
fused teeth and traced gutta-percha placed in
the sinus trac

Conversely, if the double tooth is part of a
normal complement, supernumerary teeth may
be seen in the permanent dentition.
Localized crowding or spacing can be seen in
association with double teeth in both
dentitions but in the primary, extraction is rarely
indicated.

Permanent double teeth
can be managed restoratively if the coronal
portion is not too large; however, those
with more deviant anatomy may require
extraction followed by space closure or
prosthetic replacement;

• Accessory (extra) cusps are quite a common
finding in both the primary and permanent
dentition. Indeed, the cusp of Carabelli is a small
additional cusp situated at the
mesiopalatal line of the maxillary first permanent
molar seen in up to 60% of the
population. Talon cusp, which can affect the
maxillary permanent incisors, occasionally
causes occlusal problems and tooth
displacement. Treatment usually involves cusp
removal, either with selective grinding or in
combination with pulpotomy;

Dens invaginatus (DI) is referred to as a deve-
lopmental anomaly that results from an infold-ing
within the crown prior to calcification
Dens evagination (DE) (also known as talon cusp) is a
relatively infrequent developmental abnormality
characterized by the existence of an accessory cusp-
like structure projectingfrom the cingulum area or
cemento-enamel junction (CEJ) of the maxillary or
mandibular anterior teeth both in the primary and
permanent dentition
Intra-oral photograph of the
maxillary arch shows DE
(dens evagination (on the
maxillary right lateral incisor.
Periapical radiograph of the
maxillary right lateral incisor. The
white arrow indicates the DE and
the black arrows point to the DIs.
Note that the two DIs are distinct
from the pulp chamber.
Different crown presentations of teeth with dens invaginatus. (a)
The arrow shows a palatal groove illustrated by methylene blue dye. (b)
The arrow indicates a palatal pit on the palatal surface. (c) The arrow
shows a cone-shaped tooth. (d) The arrow demonstrates a tooth with
dilated crown. (e) The arrows indicate the bilateral existence of talon
cusps in maxillary lateral incisors, and a palatal pit is present in the right

• Evaginated teeth have an external enamel-
covered projection on the surface of the
tooth. The size of these evaginations and the
degree of pulpal involvement can vary
greatly. Treatment choices are comparable with
those for accessory cusps;
Dense evaginatus appears as a cusp like elevation of
enamel, referred to as a tubercle, and is located in the central groove or on the buccal or lingual cusps of
premolars or molars and the palatal or lingual surfaces of anterior teeth
Types of dens
evaginatus.A.Occlu
sal tubercle
(arrow).B.Drawing
of palatal talon
cusp C.Labial talon
cusp
(arrow).D.Pulpal
extension into
occlusal tubercle
(arrow

• Invaginated teeth are characterized by the presence of an
enamel-lined cavity, which
is normally situated within the coronal portion of the tooth but
can extend into the
root. These cavities can range from a simple pit in an otherwise
normal tooth, to a
deep fissure associated with marked distortion of tooth form.
Treatment depends
upon severity of the invagination; pulpal infection will require
endodontics, whilst
more severely distorted teeth will often require extraction;
Palatal surface of maxillary central and lateral incisors
(arrows) showing deep pits
Periapical view of Dens Invaginatus in
maxillary incisors

• Dilaceration is an abnormal angulation between the
crown and root of a tooth, usually
affects maxillary incisors, and can occur as a
consequence of intrusive trauma to their
primary predecessors, although in the majority of
cases there is no history of trauma.
The UR1 is dilacerated as a result of previous trauma to
the URA and has
failed to erupt.

The most common scenario is a failure of the
affected incisor to erupt and, unless the
dilaceration is mild, these teeth usually require
extraction; and
A conventional panoramic view (left) and cone-beam computed tomography
sagittal section (right) through a severely dilacerated UR1.

• Taurodont or bull-like teeth have a pulp
chamber enlarged as a result
of apical migration of the furcation . This
condition generally affects the
Taurodont first permanent
molars (LR6 is also carious).
Radiographic examination revealed deep
carious lesions with large pulp chambers and
short roots in relation to teeth 75 and 85,
suggesting taurodontism.
permanent dentition in around 2.5–5% of adult
Caucasians, and can occur in isolation
or in association with other conditions such as
amelogenesis imperfecta or Down
syndrome.

The introduction of three-dimensional imaging has
improved diagnosis and treatment
planning for many abnormalities of tooth form,
allowing the orthodontist and restorative
dentist to clearly identify the relationship between
hard tissues and the pulp of affected
teeth
Cone-beam computed
tomography images of a
talon cusp associated
with
the UR1 (upper four
panels) and a double
tooth in the upper incisor
region (lower two
panels). These images
allow detailed analysis of
the relationship between
the pulp and hard
tissues.

Abnormalities of eruption
A number of systemic conditions are associated
with delayed eruption and these can
affect both dentitions . In the permanent
dentition, great individual variation
can exist in the timing of tooth eruption, with
symmetrical deviation of anything up to
2 years from the mean not necessarily being a
cause for concern. In the majority of
children, local factors will be the main cause of
any eruption disturbances that do occur
ectopic upper caninesEctopic eruption
of maxillary
central incisor ectopic eruption of maxillary first
permanent molar
Ectopic eruption of the mandibular
permanent lateral incisor. The primary
lateral incisors are still present

Systemic conditions associated
with delayed tooth eruption
Local factors causing
disturbances of tooth eruption

Primary management relies upon ensuring adequate
space exists in the dental arch
to accommodate the unerupted tooth and removing any
potential obstruction. In these
circumstances, the majority of teeth will erupt. If this
fails to happen, or the unerupted
tooth is ectopic from its normal path of eruption,
surgical exposure, with or without
orthodontic traction, may be required to accommodate
the affected tooth into the dental arch
ectopic eruption of a maxillary first molar lower teeth showing ectopic eruption of
lower permanent incisors while primary
incisors are retained.
Ectopic eruption of maxillary
central incisor through
abnormally thickened labial
frenum

Unerupted permanent maxillary incisor
A discrepancy in eruption between contralateral
maxillary incisors of greater than 6
months, or eruption of lateral incisors before the
centrals warrants radiographic investigation.
Amongst these teeth, the maxillary central
incisor most commonly fails to erupt,
but even this is seen in only around 0.13% of the
population.
Retained primary maxillary central incisorDilacerated upper lateral incisor

Failure of eruption can
be associated with the presence of supernumerary
teeth (particularly tuberculate forms
or odontomes), dilaceration following trauma to the
primary incisors, retained primary
incisors or their early extraction.
Panoramic radiograph of a 14-year-
oldgirl(with no history of dental
trauma)presented with root dilacerations
of#9,unerupted#8with enlarged
follicle,unerupted#7and#10 with delayed
root development; as well as an
impacted#22.
supernumerary teeth
(particularly tuberculate
An odontoma is impeding the
eruption of the maxillary right
lateral incisor and canine
The maxillary right central
incisor is completely
inverted and is directed
toward the nasal cavity .

However, obstruction secondary to a
supernumerary
tooth is by far the commonest cause.
Lack of space for the impacted maxillary right canine
The maxillary right central incisor is completely inverted

• In the absence of a central incisor the lateral
incisors can very rapidly drift towards
the midline, particularly in the presence of
crowding. If space needs to be created,
this can be achieved with a simple removable or
sectional fixed appliance, often with
extraction of the primary canines to provide
some space in the labial segment;
(A) Delayed eruption of an 11 due to localised space loss; (B) Delayed eruption of an 11
due to the presence of a multiple supernumerary teeth; (C) Delayed eruption of both
maxillary central incisors due to the presence of paired tuberculate supernumerary
teeth; (D) Dilaceration of an 11 due to previous trauma; (E) Cystic region in the anterior
maxilla impeding eruption of the 11 and causing displacement of the 12
(A, B) Impeded eruption of an 11 due to the presence of a supernumerary tooth.
An upper fixed appliance with a trans-palatal arch was placed; (C) The retained
primary incisor was extracted along with the supernumerary tooth and (D, E) the
11 surgically exposed with bonding of a gold chain and piggy-back mechanics
instituted utilising nickel-titanium and stainless steel archwires to mechanically
erupt it; (F) Eruption of the 11; (G) Orthodontic bracket bonded to the 11 for final
alignment; (H) Removal of the fixed appliance and placement of a labial bonded
retainer for retention

• For those associated with a supernumerary
tooth, if sufficient space is present and
the incisor is superficially placed, it will usually
erupt within 12 months of removing
the supernumerary (although consideration can
be given to bonding an attachment,
particularly if a general anaesthetic is required
for the extraction).
(A, B) An impacted 21 due to the presence of a supernumerary tooth; (C, D)
Raising of a mucoperiosteal flap to surgically expose and identify the
supernumerary tooth, which was palatal to the 21; (D) Removal of the
supernumerary tooth and bonding of a gold chain attachment to the palatal
surface of the 21; (E) Closure of the soft tissues and gold chain temporarily
secured to the adjacent 11 with composite adhesive
(A) Unfavourably positioned 21 due to severe dilaceration and an
ectopic position of the 23; (B) The 21 was surgically extracted
and the 23 exposed and bonded; (C) An upper fixed appliance
and ‘piggy-back’ mechanics used to align the 23; (D) Orthodontic
alignment of the 23 into the 21 position

For incisors impacted
in a higher position, the supernumerary should
also be removed. For children under
the age of 10, the permanent incisor follicle
should be left undisturbed and eruption
monitored. If the tooth fails to erupt, it can be
exposed (and bonded with an attachment
if it remains high) when it is more mature. In
those over 10 years of age,
exposure with placement of an attachment
should be carried out at the time of
(A) Delayed eruption of an 11 due to localised space
loss; (B) Delayed eruption of an 11 due to the
presence of a multiple supernumerary teeth; (C)
Delayed eruption of both maxillary central incisors
due to the presence of paired tuberculate
supernumerary teeth; (D) Dilaceration of an 11 due
to previous trauma; (E) Cystic region in the anterior
maxilla impeding eruption of the 11 and causing
displacement of the 12

The incisor should erupt spontaneously
and the bracket
and chain can then be removed . If it fails to
erupt, orthodontic traction
can be applied without the need for further
surgery;
Extracted tuberculate supernumeraries and the effect of these
teeth on the
developing dentition.

• In the absence of any supernumerary, a mature impacted
incisor delayed for more
than 6 months should have a bracket and gold chain placed
and be observed for 6
months. Surgery on immature incisors should be delayed
until apexification is complete
and observed for 12 months before applying traction; and
In this case, the relatively low vertical position of the central incisors in
relation to the occlusal plane favoured spontaneous eruption

• Dilacerated incisors can only be accommodated if
the degree of dilaceration is mild;
more severe cases may result in the root perforating
the maxillary labial plate if the
crown is aligned .
A conventional panoramic view (left) and cone-beam computed tomography
sagittal section (right) through a severely dilacerated UR1.

Unerupted permanent maxillary canine
The permanent maxillary canine fails to erupt correctly in approximately 2% of Caucasian
children and these teeth often require orthodontic management . Deviation
from the normal path of eruption can occur in either a palatal or buccal direction,
but in the majority of cases (up to 85%) it will be palatal and the tooth will become
impacted. Although the canine can also impact on the buccal side or within the line
of the arch, these cases are often manifestations of crowding rather than true ectopia.
Buccal crowding of the
maxillary canines.

A number of reasons have been suggested
to explain the particular vulnerability of
the maxillary canine to deviation from its
normal eruptive path:
• A developmental position that begins high
in the maxilla and results in a long path
of eruption;

• Reliance upon the maxillary lateral incisor root for guidance of eruption, which can
be lacking if these teeth are diminutive or congenitally absent (Brin et al, 1986);
• Retention of the primary canine obstructing normal eruption;
• Chronology of eruption, in the maxillary arch the canine often erupts after the first
premolars; therefore space can be at a premium; and

• A genetic susceptibility (based upon
observations that demonstrate a familial
tendency,
occurrence of other dental anomalies in
association with ectopic maxillary
canines and a female predilection) .

Clinical examination
The eruptive path of maxillary permanent
canines are notoriously unpredictable ; however,
by the age of 10–11 years, these teeth should be
palpable in the buccal
sulcus adjacent to the lateral incisor root . If one
or both are not, then an
abnormal path of eruption should be suspected
and radiographic investigation instigated
Panoramic radiographs
demonstrating seemingly normal
development and eruption of the maxillary
permanent canines in a girl at the age
of 9 and 11 years (upper and middle
radiographs).
However, by the age of 14
years, whilst the UL3 has erupted normally,
the URC is retained and the UR3 has
become ectopic and palatally impacted
(hypoplastic first permanent molars have also
been extracted).

Other clinical features that may alert the
clinician to possible
impaction include:
• A palatal bulge;
• Delayed eruption, marked distal angulation or
retroclination, microdontia or absence
of the permanent lateral incisor; and
• A firm primary canine (particularly beyond the
age of 14 years) indicating a lack of
resorption.
Maxillary permanent canines
palpable in the buccal sulcus. The canine
position is given away by the distal
inclination and slight proclination of the
permanent lateral incisor crowns.

Radiographic examination
Radiographic examination is required to
demonstrate the presence of the canine, its
position within the maxillary arch, the condition
of adjacent teeth (particularly the degree
of resorption associated with the primary canine
or presence of any resorption associated
with the permanent incisors) and any other
pathology.

The position of the canine should
be evaluated in all three planes of space:
• Buccopalatal relationship to the dental arch;
• Height relative to the occlusal plane;
• Angulation relative to the mid-sagittal plane;
and
• Distance from the mid-sagittal plane.

Two films are required to definitively establish
canine position and the parallax (or
tube-shift) technique is commonly used to
achieve this . Parallax is the
apparent displacement of an object when
observed from two different positions and,
in radiological terms, relies upon taking two
views with the X-ray tube in a different
position for each view.
a, b Comparison of ini-tial
intraoral periapical radio-
graph (IOPA) with IOPA
taken with 20 ° distal shift
(SLOB technique): distal
shift of 23 is seen on
second IOPA

Horizontal parallax uses a horizontal shift in the X-
ray tube
(usually with successive periapical views taken
with the tube moved horizontally),
whilst vertical parallax uses a vertical shift in the
tube (usually achieved with a panoramic
and anterior occlusal view).
Vertical parallax to localize maxillary canine position. In the upper
radiographs, the coronal tip of both maxillary canines lie midway along the roots of the lateral
incisors on the panoramic radiograph; on the anterior occlusal radiograph they are clearly
midway along the crowns of the lateral incisors. These canines have moved down
as the X-ray tube has moved up and are therefore buccally positioned. In the middle
radiographs, the UL3 is situated below the root apex of the UL2 on the panoramic
radiograph; on the anterior occlusal radiograph it is now situated above the tip.

The advantage of the parallax technique is that it
always involves an intraoral view, which gives
good detail of the canine and incisors
The canine
has moved up as the X-ray tube has moved up and is therefore positioned palatally.
In the lower radiographs, the coronal tips of both maxillary canines are situated just below
the apices of the lateral incisors on the panoramic radiograph; on the periapical radiographs
they are in a similar position. These canines have not moved significantly as the X-ray tube
has moved and are therefore situated in the line of the dental arch.

• More recently, the use of cone-beam computed
tomography has been described to
• precisely locate the position of ectopic canines in
three dimensions.
• Computed tomography also allows a more
detailed examination of related structures
• and has found that up to 40% of lateral incisors
exhibit some resorption in the presence
• of ectopic canines .
Sagittal (A) and axial
(B) slices of cone-beam
computed tomography
(CBCT) show an
impacted canine
causing mild root
resorption of the
lateral incisor

However, the use of cone-beam computed
tomography cannot be justified for the routine
localization of these teeth because of the
significantly increased radiation dose.
A 14-year-old girl with a right maxillary impacted
canine .A.A periapical radiograph of the impacted
right canine shows superimposition of the crown of
the canine on the distal part of the root of the lateral
incisor .B .A periapical radiograph of the impacted
right canine obtained from a more distal angle than
that shown in A that eliminates the superimposition
and confirms that the canine crown is palatal to the
central incisor root. These findings suggest that the
impacted tooth should be exposed surgically and
orthodontic traction should be performed from the
palatal side. C-E. Three-dimensional cone-beam
computed tomographic images show the canine
crown palatal to the central incisor root and labial to
the lateral incisor root. A palatal surgical and ortho-
dontic approach to this tooth will fail because the
root of the canine can be seen on these images
labial to the root of the lateral incisor, with its root
apex distal to that of the lateral incisor

Interceptive treatment
An impacted canine can be associated with
unwanted movement, crowding and a significant
risk of damage to adjacent teeth, particularly the
lateral and occasionally the
central incisors and often requires surgical
intervention combined with prolonged
orthodontic treatment in order to accommodate
it in the maxillary arch.
Resorption
of the UR2 (left) and the
UR2, UR1 and UL2 (right)
root apices in association
with impacted maxillary
canines.

Some
evidence exists from prospective studies to
suggest that early extraction of the primary
canine can help prevent a palatally ectopic
permanent canine becoming impacted
particularly if there is a lack of
crowding or headgear is used to create space
Panoramic radiographs
showing improvement in the position of an
impacted UR3 after extraction of the primary
canine.

Whilst this evidence is weak, with radiographic
evidence of an ectopic position and a
lack of normal resorption associated with the
primary canine, consideration should be
given to elective extraction of this tooth ..
(a)Pretreatment panoramicradiograph.(b)The
unerupted canine is going to migrate across
themandibular midline, and its crown tip is near the
apex of the lowerright first incisor root.

The best results
seem to be obtained under the following
conditions:
• Patient aged between 10 and 13 years and in
the mixed dentition;
• Canine positioned distal to the midline of the
lateral incisor root and less than 55° to
the mid-sagittal plane; and
• An absence of crowding in the maxillary arch
Impacted upper right canine

If radiographic evidence of an improvement in
canine position is not evident within 12
months of extraction, further treatment should
be considered.
(a, b) Vertical parallax using a combination of occlusal and panoramic radiographs: (a)
DPT view, (b) occlusal view. (Note 1: The canine tip moves in the same direction as the
radiographic tube between the two images and Note 2: The radiographic magnification of
the maxillary right permanent canine on the panoramic image due to its palatal position.)

Management
The maxillary canine is a large tooth,
possesses the longest root in the dentition
and
forms an important aesthetic and functional
component of the occlusion. Every effort
should be made to try and accommodate
this tooth in the dental arch.
Ectopic permanent maxillary canines in a ten-year-old patient: (a) the untreated caries;
and (b) the unerupted permanent left maxillary central incisor are higher treatment
priorities

However, a
number of general factors should be taken into
consideration when treatment planning
for an impacted canine:
• Patient attitude to treatment;
• Position of the canine;
• Presence of any associated pathology; and
• Underlying malocclusion.
Developmentally normal canines. The left permanent maxillary canine was not palpable buccally but
was resorbing the root of the deciduous canine normally. The permanent canine would be expected to
erupt within nine months: (a) clinical appearance; (b) radiographic appearance

The treatment of choice is generally surgical
exposure followed by orthodontic alignment.
However, the patient may not wish to undergo
the extended orthodontic treatment that
might be required to accommodate a canine
following surgical exposure, or the canine
may be in such a poor position that orthodontic
alignment is not practical. In this case,
autotransplantation of the tooth directly into the
correct position is a further option.
Alternatively, a decision can be made to extract
the impacted canine or, more rarely,
leave it in situ
An ectopic permanent maxillary canine
that failed to erupt following extraction
of the deciduous canine. (Note: the
slight improvement in its position
between (a) pre-extraction and (b) one
year post-extraction)

Surgical exposure and orthodontic alignment
Surgical exposure aims to remove any hard or
soft tissue obstruction that may be impeding
eruption and can be enough to induce the
canine to erupt, particularly those in more
favourable positions.
Surgical open (left panels) and closed (right panels) exposure of palatally
impacted UL3s followed by orthodontic alignment with fixed appliances.

For those that fail to respond or are
more displaced, orthodontic
alignment will also be required .
Surgical open (left panels) and closed (right panels) exposure of palatally
impacted UL3s followed by orthodontic alignment with fixed appliances.

When embarking upon the prescription of
surgical exposure and orthodontic alignment, the
following should be remembered:
• This treatment usually involves fixed appliances and
can be time consuming; therefore
patient motivation and compliance must be high;
Osseointegration of the wire chain was foundwhen
the site was reopened.Arrowsindicate bone
tissuepassing through the chain

• The canine must be in a position that makes
orthodontic alignment an achievable
goal. In particular, those situated as high as the
apical third of the incisor roots, beyond
the lateral incisor towards the midline or at an
angle of greater than 55° to the midsagittal
plane can be more difficult to align ; and
The prognosis for successful
orthodontic alignment of a palatally impacted
maxillary canine is influenced by the position of
this tooth. As the height increases, distance
towards the dental midline reduces or angle to the
mid-sagittal plane increases beyond 55°, the
prognosis worsens.

• Space needs to be available in the maxillary
arch for the canine. If this is lacking, it
will need to be generated, by either distal
movement of the buccal segment or extraction.
If the lateral incisor is diminutive, some
consideration can be given to extracting
this tooth; however, first premolars are the usual
choice. It is desirable to ascertain
that an impacted canine will erupt before
extracting a premolar, but this is not always
practical.
A 13-year-old girl with a left canine impaction unresolved
after three years of orthodontic treatment.A.Intraoral
photographshowing the intrusive effect and open bite
created after eruptive force was applied to the
unresponsive left maxillary canine.B.Periapicalradiograph
showing minimal changes in cervical area.C.Axial and
transaxial slices of the canine showing loss of integrity of
its root outlineby means of invasive resorption and
replacement by soft tissue

The site of impaction will be an important
determinant of the surgical technique used
for exposing a maxillary canine .
• For those on the labial side, the aim is for the
tooth to be erupted through attached
gingiva. Therefore, if the crown is located below
the mucogingival junction, an open
procedure is appropriate and the crown simply
uncovered.
A vestibular flap was opened to expose the
canine and allow removal of the supernumer-
ary, and a minitube was bonded to the labial
surface of the impact-ed tooth.
The flap was repositioned in its original location and
sutured with Vicryl 4-0 absorb-able thread

For canines above the
mucogingival junction, a closed exposure and
bonding with gold chain is the treatment
of choice unless the canine is labial to the lateral
incisor; in these cases, an
apically repositioned flap will provide the best
chance of the tooth erupting through
an attached gingiva ;
Gold chain attached to a buccally impacted permanent maxillary
canine (note the links of chain visible through the mucosa).
Pre-op, showing the edentulous areaat
upper left canine region & the
prominence created by the labially
impacted tooth
Flap apically positioned andsutured
Post-op 1 week showing orthodontic
button with a ligature wire

The closed eruption technique is used in cases where the
impacted tooth is farther from the labial cortex and ideal apical
positioning of the soft tissue at the time of surgery is not possible.
In this technique a mucoperiosteal flap is raised just enough to
expose the bone covering the crown of the impacted canine.
Enough bone is removed to allow for the placement of a bonded
bracket which is secured passively to the archwire via a ligature
wire or a chain. The flap is then replaced and sutured in its
original position. The bracket is activated after the post-operative
appointment. Final soft tissue recontouring is postponed until
after the completion of the orthodontic treatment.

For the apically positioned flap the site is anesthetized by local infiltration
and an approximately 12mm wide horizontal incision (using a 15, 15C or 12
scalpel blade) is made into the mid-crestal area of the ridge coronal to the
impacted tooth. Two vertical releasing incisions (using the same blade) are
made connecting the horizontal incision and extending apically into the
vestibular mucosa. A split thickness flap is elevated using the scalpel blade
and periosteal elevators. If present, the bone covering the facial aspect of
the canine crown is removed.

Rotary and/or hand instruments such as chisels are used carefully so as to
prevent damaging the enamel of the impacted canine. The flap is repositioned
apically and sutured in place so that its keratinized portion covers 2-3mm of the
enamel and the CEJ (cementoenamel junction) of the exposed tooth. The flap is
sutured in place with horizontal sutures using 5-0, or 6-0 resorbable or non-
resorbable sutures (if non-resorbable sutures are used they must be removed 1-2
weeks post-operatively). An orthodontic bracket can be bonded to the exposed
enamel and secured passively to the archwire via a ligature wire or a chain. These
are then activated one week post-operatively
Surgical exposure of both impacted canines. (A, B) Horizontal incisions on
the keratinized gingiva with two vertical incisions were designed. (C) The
flap was elevated, and the right maxillary canine was exposed. (D) The left
canine crown was exposed following removal of the labial bone. (E, F) After
bonding with an orthodontic button on the labial surface of the left canine,
the flaps were positioned apically and sutured bilaterally. (G, H) The stitches
were removed 1 week postoperatively

• For palatally impacted canines an open or
closed technique can be used, depending
on the position of the tooth. In terms of outcome
there is little evidence that one
technique is significantly better than the other .
Coverplate (note the periodontal
dressing material shining
through the acrylic appliance)
Exposed palatally impacted
permanent maxillary canine 1
week post surgery.
Incisions for open exposure of a
palatally impacted permanent
maxillary canine.
Spontaneous eruption following
open exposure.

A variety of techniques that allow orthodontic
traction to be placed on an impacted
canine have been described, but all will usually
involve direct bonding of an orthodontic
bracket .

Either removable or fixed appliances can be
used to apply traction,
but for either technique space is required in
the dental arch. For canines in less
favourable positions, fixed appliances are
essential, and as this process can be quite
anchorage demanding, reinforcement
should be considered.
Intraoral photographs of a case where both maxillary canines were impacted, the right buccally,
the left palatally (a). Inphotograph b, the right canine has erupted and is being pulled down into
position. The left palatally impacted caninehas been uncovered but is not visible. In view c the left
canine that had initially been moved horizontally in a highposition toward its buccal position is
now being drawn slowly occlusally with force applied to a bracket bonded to thetip of its cusp.
Treating impacted canines in this way orthodontist can move them into the arch in correct
axialinclination needing no torque adjustment.
The oral surgeon has incised a buccal
flapin order make two osteotomy cuts
with afine round bur in the cortical
bone onemesial and one distal to the
canine asshow by the white lines in
photo.

Using fixed appliances,
traction can be applied with flexible piggyback
archwires, elastomeric chain or string,
rigid buccal arms or even magnets. The choice
of technique will depend largely upon
canine position and preference of the
orthodontic operator.

Autotransplantation
Autotransplantation involves the surgical removal
of an impacted canine and subsequent
implantation into its normal position within the
maxillary alveolus. Space will need to be
available to accept the transplant and a short
period of orthodontic treatment may be
needed to generate this, particularly if a primary
canine has been retained; but this
process will generally be less time consuming than
aligning a canine with orthodontic
traction .
A, Clinical picture of case withankylosis and infra‐occlusal
position oftransplanted canine. B, Clinical picture of
casewith gingiva recession

If the position of the ectopic canine prevents any
initial orthodontic
treatment, the canine can initially be removed and
‘parked’ under the buccal mucosa
whilst the necessary orthodontics is undertaken.
Once space has been created for the
tooth, a secondary surgical procedure can be
undertaken to autotransplant the tooth.
Closed flap technique was performed for the maxillary canine to erupt
and orthodontic traction was applied
to align the canine into the lateral position.

A disadvantage of autotransplantation is that
these teeth can be susceptible to subsequent
ankylosis or external root resorption and
generally have a reduced long-term
prognosis in comparison to canines aligned
orthodontically. In addition, the success of
this technique is highly dependent upon the skill
of the surgical operator.
Autotransplantation of palatally impacted maxillary canine

• Surgical removal of the canine should be as
atraumatic as possible (which can be
difficult because these are often the very
canines that are in the worst position) to
avoid subsequent ankylosis;

• The canine should be kept out of occlusion and
semi-rigidly splinted for a maximum
of 3 weeks following the transplant;
Severe complication after autotransplantation of bilateral palatal impacted maxillary
canines: a lesson to learn
the delayed wound healing and wound dehiscence at
the palatal incision. B. Intra-oral radiographs. Note the
ongoing process of inflammatory root resorption.

• Once the splint is removed, the canine should
be root canal treated to reduce the risk
of subsequent external resorption; and
• Orthodontic movement of transplanted canines
is possible but often limited in scope.

This technique has can produce survival rates
approaching 15 years in a majority of
patients, although most of these transplanted
canines will demonstrate some signs of
resorption, mobility and periodontal destruction
Transplantation of an ectopic maxillary canine. A, Vestibular location. B, trapezoidal incision. C‐D, Osteotomy with a fine
surgical drilland chisels. E, Preparation of the recipient socket with chisels. F‐G, Removal of the graft with careful
handling of the periodontal ligament. H‐K,Positioning of the donor tooth into the recipient socket and suturing of the
trapezoidal flap. L, Fixation in the orthodontic arch with a bracket andorthodontic wire in infraocclusive position

Management of retained primary canines in the adult
patient. A retained ULC
associated with a palatally impacted UL3 in a 42-year-
old woman. Fixed appliances were used
to create space for this tooth prior to extraction of the
ULC and transplantation of the
permanent canine (upper two panels). A retained URC
with a poor long-term prognosis and
aesthetics in a 43-year-old woman who previously
had the impacted UR3 extracted as a
teenager (even though the UR2 was absent) (panels
three and four). Following a period of
fixed appliance treatment to redistribute space,
implant restorations were used to replace the
UR3 and an absent LL5 (panels five to eight).
If a decision is made not to accommodate the
impacted canine, then it can be extracted
or left in situ. In either case, if the primary canine
remains, the patient should be aware
of the long-term prognosis and the likely need for
eventual replacement of this tooth
.
Extracting the canine or leaving it in situ

Alternatively, if the primary canine is not
retained, a good contact
between the lateral incisor and first premolar
should be established . This
may already be present if there is no spacing
in the arch and orthodontic treatment may
be avoided.
Poorly positioned maxillary canines electively extracted as part of an
orthodontic treatment plan. The maxillary first premolar makes a good substitute for the
canine.

However, if there is any residual spacing, either
space closure or prosthetic
replacement will be necessary and in both
cases, some orthodontic treatment may be
required (particularly if there is also an
underlying malocclusion). A number of factors
should be remembered when extracting a
permanent canine:
Closeapproximationofim
pactedleftuppercaninetor
esorbedrootofleftupperla
teralincisor.

This may already be present if there is no spacing in
the arch and orthodontic treatment may
be avoided. However, if there is any residual spacing,
either space closure or prosthetic
replacement will be necessary and in both cases, some
orthodontic treatment may be
required (particularly if there is also an underlying
malocclusion).

• If it is in a poor position, this will almost
certainly involve a general anaesthetic;
• If the extraction is prescribed because the
patient has declined orthodontic treatment,
any options to accommodate the canine in the
future will be lost;
A number of factors
should be remembered when extracting a permanent
canine:
Substitution of retained canines with first
maxillary premolars. Case report

• If the extraction is part of an orthodontic treatment plan, either unilaterally or in
combination with other teeth, space distribution will need to be considered within
the context of the whole malocclusion. Ideally, space should be closed and a
contact
between the lateral incisor and first premolar established (Box 10.4). However, this
may not be possible in the absence of crowding or an increased overjet;
year-old female patient with impacted upper canines, poorly re-
stored lower right first molar, extracted lower left first molar,
decayed upper first molars, horizontally impacted lower right
third molar, and Class I molar relationship on right side before
treatment
Impacted upper canines
visible on sagittal cone-
beam computed
tomography.
Lower canines, first and sec-ond premolars, and second molars bonded, with
anterior teeth bypassed to prevent proclination. B. Bite raised to avoid occlusal
interference.
After surgical removal of im-pacted upper canines and extraction of
lower right first molar, lacebacks added in lower buccal segments to
help relieve crowding.
lower anterior teeth bonded
and space closure initiated in
upper arch.
Two months after surgery, upper
brackets bonded and leveling initiated
with .014" nickel tita-nium archwire

• If space is not to be closed, prosthetic replacement of the canine with a single unit
bridge or implant will be required; and
• In the presence of severe resorption and a poor long-term prognosis associated with
any incisor teeth , canine extraction should be avoided and, ideally,
this tooth accommodated in the dental arch .
Resorption
of the UR2 (left) and the
UR2, UR1 and UL2 (right)
root apices in association
with impacted maxillary
canines.
Marked
resorption of the
UR1 in
association with
an impacted
canine. The
UR1 was
extracted, the
canine brought
down into the
arch and then
modified with
composite
to resemble the
central incisor.

The option to leave a maxillary canine in situ is
usually made on the basis that the patient
is happy with their dental appearance and does not
wish to have any form of
treatment.
• Ideally, the canine should not be closely associated
with the erupted dentition;
• There should be no evidence of any pathological
change or root resorption affecting
the adjacent teeth;
Extraction of an Impacted Maxillary Canine with Immediate
Implant Placement

• Regular radiographic review is recommended
in the growing patient because incisor
roots can be vulnerable to resorption; and
• Longer-term pathological change, such as
follicular enlargement and cyst formation,
should also be monitored radiographically.
On this figure composed of 3 X-rays of 3 individuals of the same
family (2 brothers and 1 sister), you can see, for the girl, the first
signs of the impaction of an upper right canine as well as the
enlarged follicular envelope and the congenital absence
(hypodontia) of a lower incisor

Putting a first premolar in the canine position
The morphology of the maxillary first premolar differs from that of the canine in
several respects:
• The root is smaller and often bifid, lacking the characteristic wide and prominent
labial surface seen in the canine; and
• The crown is also smaller from the buccal aspect and there is an additional
palatal cusp.
extraction of the maxillary
canines and the
mandibular second
premolars,

However, from the buccal aspect the premolar crown
does resemble that of
the canine and this tooth can make an excellent
substitute, which can be enhanced
by a few modifications:
• The premolar root should be placed more buccally in
the maxilla to create a
canine eminence;
Substitution of impacted canines by maxillary first premolars: A
valid alternative to traditional orthodontic treatment
American Journal of Orthodontics and Dentofacial Orthopedics
January 2013 Vol 143Issue 1

• The crown can also be rotated
mesiopalatally, which increases the
mesiodistal
width, helps to hide the palatal cusp and
improves the occlusal relation with
the mandibular canine;
• The palatal cusp can also be ground to
reduce its prominence;
Unusual Extraction Combinations in Patients with
Impacted Maxillary Canines
JCO/OCTOBER 2019

• The premolar should be intruded to
increase height of the gingival margin
and the buccal cusp built up with
composite or veneered (if the premolar
is
small) to increase crown length and
mimic a canine; and
• Group function in lateral excursion is
preferable to guidance, which avoids
heavy loading of the less robust
premolar root.
World journal of orthodontics 5(4):358-64 · February 2004
First premolars substituting for maxillary canines--esthetic, periodontal and
functional considerations
Intrusion and incisal build-up of the right first
premolar substituting for the canine in space-
closure case with absent lateralincisor. The
intrusion is achieved with small mesial and distal
archwire step-bends (a). After treatment, the
intruded premolar (b)has been provided with a
hybrid composite incisal build-up (case treated
by Dr Marco Rosa, Trento, Italy). Note the more
normalgingival margins at the end of treatment
(c)

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