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Dental Press J Orthod. 2022;27(1):e22ins1
https://doi.org/10.1590/2177-6709.27.1.e22ins1
Alberto CONSOLARO1,2
https://orcid.org/0000-0002-5902-5646
Mauricio de Almeida CARDOSO3
https://orcid.org/0000-0002-6579-7095
Renata Bianco CONSOLARO4
https://orcid.org/0000-0001-8841-6913
Raquel Assed Bezerra SEGATO2
https://orcid.org/0000-0002-0230-1347
Volume 27 - Number 1 - Online
ORTHODONTIC INSIGHT
Canines and inflammatory external
apical resorption in healthy maxillary
lateral incisors due to occlusal trauma:
when to detect the position of maxillary
canines, to prevent it?
(1) Universidade de São Paulo, Faculdade de Odontologia de Bauru (Bauru/SP, Brazil). (2) Universidade de São Paulo,
Faculdade de Odontologia de Ribeirão Preto, Programa de Pós-graduação em Odontopediatria (Ribeirão Preto/SP,
Brazil). (3) Faculdade de Medicina e Odontologia São Leopoldo Mandic, Programa de Pós-graduação em Ortodontia
(Campinas/SP, Brazil). (4) Centro Universitário de Adamantina (Adamantina/SP, Brazil).
Submitted: December 07, 2021 • Revised and accepted: December 20, 2021
consolaro@uol.com.br
How to cite: Consolaro A, Cardoso MA, Consolaro RB, Segato RAB. Canines and inflammatory external
apical resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position
of maxillary canines, to prevent it? Dental Press J Orthod. 2022;27(1):e22ins1.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
2
ABSTRACT
Justification: Canines represent corners in the dental arch,
and are important features in facial esthetics, as they support
the upper lip, wing of the nose, and influence the nasolabial fold
and the appearance of facial aging. In the laterality movements,
the canines guidance coordinate the opening and closing of the
teeth, saving the TMJ from sudden movements.
Discussion: As a result of the lack of eruption or the inadequate
positioning of the maxillary canine, the loss of the laterality guide
may occur, which will then occur in the maxillary lateral incisor,
inducing lesions of “occlusal trauma”, such as inflammatory root
resorption. Likewise, without well positioned canines, there may
be premature aging and change in facial esthetics.
Conclusion: In order to avoid problems with eruption and posi-
tioning of the maxillary canines, early diagnosis is made by ana-
lyzing their position and their relationship with the other teeth,
and in the three-dimensional context of the maxilla, between
8-10 years of age. Preventive measures can create bone space
and direction so that the maxillary canines can occupy their po-
sition in the dental arch.
Keywords: Unerupted canines. Inflammatory root resorption.
Occlusal trauma.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
3
RESUMO
Justificativa: Os caninos representam esquinas na arcada den-
tária e são importantes na estética facial, por suportarem o lábio
superior e a asa do nariz e influenciarem no sulco nasolabial e
no aspecto do envelhecimento facial. Na guia de movimentos de
lateralidade, os caninos coordenam a abertura e o fechamento
dos dentes, poupando a ATM de movimentos bruscos.
Discussão: Como resultado da falta de erupção ou do posicio-
namento inadequado do canino superior, pode ocorrer a perda
da guia de lateralidade, que se fará no incisivo lateral superior,
induzindo lesões de “trauma oclusal”, como a reabsorção api-
cal externa inflamatória. Do mesmo modo, sem os caninos bem
posicionados, pode haver envelhecimento precoce e estética
facial modificada.
Conclusão: Para não acontecerem problemas de erupção e po-
sicionamento dos caninos superiores, o diagnóstico precoce é
feito pela análise da sua posição e da sua relação com os de-
mais dentes e no contexto tridimensional da maxila, entre os
8 e 10 anos de idade. Medidas preventivas podem criar espaço
ósseo e direcionamento para que os caninos superiores ocu-
pem a sua posição na arcada dentária.
Palavras-chave: Caninos não irrompidos. Reabsorção apical
externa inflamatória. Trauma oclusal.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
4
INTRODUCTION
John Hunter in the UK denominated the teeth, nearly 300 years
ago; except for the canines, which were already named, and
they were also known as fangs — especially in wild beasts,
which used them to seize their prey, by fixing these fangs in
their flesh. The large conical crowns, with long, wide roots,
supported in the maxilla by a very dense bone, allowed the
animal to shake its neck repeatedly, a strategy used to kill the
prey. In humans, canines are outstanding, although they are
still smaller than they are in animals.
Canines are the corners of the dental arch. By analogy, street
corners in cities are very important in the flow of people, in
the logistics of cars and in the esthetics of metropolises. Inthe
mouth, the same occurs with the canines, which guide and
determine the paths of food, chewing and the lateral openings
of the mouth, sparing and preserving the TMJ. But canines are
much more than corners of the arches.
The roots of the maxillary canines and the surrounding bone
physically support the wing of the nose and upper lip, without
revealing the nasolabial groove, which descends to the corner
of the mouth, or commissure. Anatomically, the root and peri-
odontal tissues of the maxillary canine are located below the
wing of the nose. The bulging bone of the canine prominence
on the buccal surface of the maxilla supports the upper lip,
giving the nasolabial fold an appearance of filling.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
5
The wing of the nose and the nasolabial fold are very important
in the esthetics of the face. Canines prevent the appearance
of premature facial aging, by preserving the nasal shape and
volume of the upper lip. In patients without one or both the
canines, the role of the canine in esthetics and facial aging is
highlighted. The maxillary canines prevent the upper lip from
drooping and accentuating the nasolabial fold, thanks to their
proximity to the piriform aperture.1
WHERE IS THE CANINE? PREVENTIVE MANAGEMENT
How can the lack of eruption, disturbances in position and even
loss of canines be prevented? These frequent problems occur
because the canine is the last tooth to occupy its place in the
dental arch, with the exception of the third molars.
The lack of space to accommodate the canines changes the
shape and volume of the dental arch, and is capable of gener-
ating asymmetries expressed in the smile, such as ungraceful
laughter. Almost always, the canine that failed to appear is inside
the bone, unerupted, or it has erupted and is in an inappropri-
ate position. Many people have a smaller jaw, with lack of space
for all the teeth, thus requiring orthodontic and orthopedic cor-
rections performed by specialists. The absence of maxillary and
mandibular canines due to partial anodontia is very rare.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
6
The ideal is to know where the maxillary canines are when the
patient is between 8-10 years old, after a consultation with the
pediatric dentist and/or the orthodontist. Before nine years of age,
no permanent tooth will have undergone complete development
of its root.2
To know the exact position of the maxillary canine, panoramic
and periapical radiographs are necessary, as well as tomographic
images, including 3D images of the maxilla. At this time, the spatial
relationship with the other teeth and its position in the maxilla is
established. For other jaw problems, this examination of the jaws
and teeth should be done when the patient is six years old.
Two factors contribute to the greater possibility of eruption disor-
ders in maxillary canines:
1) It is the last tooth to position itself in the arch.
2) It is the only tooth that is related to two other teeth to enable its
normal eruption to occur, as it is located on top of the decidu-
ous canine and the germ of the permanent premolar.1
If the changes are diagnosed at this age, there is a set of procedures
that anticipate problems with the canines, and they will occupy their
proper position in the dental arch and in the bone that supports
the soft tissues, including the upper lip and the wing of the nose.
Without presence of the original canines, the middle third of the
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
7
face is left with a fallen appearance that tends to be noted by an
attentive observer. The canine gives the midface an appearance of
youthful, fullness and volume.
OCCLUSAL FUNCTIONS OF THE CANINES
The canines are not only key parts in the esthetics of the face,
but they are also fundamental for the proper functioning of
the set of teeth and mouth, as we can point out:
1) When we move the mandible to one side, the teeth are guided
by the canines and thus lift and separate the maxillary and
mandibular posterior teeth, to enable the lateral movement
to occur.
2) In this way, the canines coordinate these neuromuscular
functions, as they capture the stimuli in their periodontal
tissues and, thus, conduct the mandibular movements of
closing and laterality, to protect the TMJ.
WHEN THE LATERAL TEETH ACT AS CANINES,
AND THE EIGHT SIGNS OF OCCLUSAL TRAUMA
Not rarely, healthy maxillary lateral incisors — that is, without
caries, without pulp necrosis and without previous history of
dental trauma — may be found with external inflammatory
external apical resorption unilaterally or bilaterally,3,4 as in
Figures 1 and 2.
Dental Press J Orthod. 2022;27(1):e22ins1
8Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
Figure 1: Four maxillary lateral incisors that have served as laterality guide for a period
longer than 1 year, which would naturally and properly occur as function of the maxillary
canines. The masticatory and occlusal overload induced establishment of the occlusal
trauma lesion in its most advanced form, and it is characterized by inflammatory root re-
sorption in plane ( arrows ). Pulp vitality is preserved.
In this situation described above, our experience with several
cases has almost always led us to indicate this resorption as
being part of the lesion or disease called “occlusal trauma”,
with late manifestation of months and years of progression
and preceded by other manifestations, which we will discuss
next. Since the beginning of this “occlusal trauma” lesion, it has
been caused by the chewing overload determined on the max-
illary lateral incisors in this situation, when these teeth have
been used as a guide for the movement of laterality, and not
the canines (Figs 1 and 2).
Dental Press J Orthod. 2022;27(1):e22ins1
A
B.1
D.1 E.1
C.1
B.2
D.2 E.2
C.2
9Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
Figure 2: Inflammatory root resorption in lateral maxillary incisors, when they have acted as
a laterality guide for a long time; this can occur unilaterally or bilaterally. In this case, the 3D
tomographic images highlighted the bilateral resorptions in the vestibular (A, B.2 and C.1) and
palatal (D.2 and E.1) views, representing two advanced occlusal trauma lesions. In B.1, C.2, D.1
and E.2, sagittal tomographic images of the lateral incisors can be seen. Analyzing the maxil-
lary canines between 8 -10 years old can prevent this situation (the patient was a 31-year-old
woman with a history of previous orthodontic treatment).
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
10
The structure of the maxillary lateral incisors is much more
fragile than that of the canines; they are unable to dissipate all
the force received and, slowly and individually, the cemento-
blasts of their apical third become necrotized, thus promoting
this resorptive process as the last manifestation of the “occlu-
sal trauma” injury, at all times maintaining pulp vitality.3,4
The term “injury” means any temporary or permanent ana-
tomical change in our tissues, irrespective of their nature and
origin. The term “disease” or illness almost always implies an
evolutionary process of a clinical and imaging condition that is
repeated when those causes act on the site.
The injury or disease called “occlusal trauma” may be caused
by a) occlusal interference; b) chewing overload; c) parafunc-
tional habits, such as bruxism and clenching; and d) active or
loose orthodontic retainers. For the “occlusal trauma” injury to
become fully established, a prolonged time is required, longer
than one year.
The chewing overload can be on one tooth only, as it can occur
when the laterality guide function of opening the maxillary and
mandibular teeth performed by the canines begins to be per-
formed by the maxillary lateral incisors instead, either unilat-
erally or bilaterally.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
11
Sequentially and gradually3,4, the “occlusal trauma” injury estab-
lishes itself in the periodontal supporting tissues and shows:
1) radiographic thickening of the lamina dura;
2) irregular enlargement of the periodontal space;
3) increased periapical or lateral bone density;
4) vertical bone loss in the cervical region of the root, with no
sign of periodontal pocket or other inflammatory signs.
In the coronal tissues, simultaneously with the previous men-
tioned signs, the following may appear:
1) the attrition wear facet in the areas of occlusal interference;
2) “V”-shaped gingival recession;
3) presence of abfraction in the cervical enamel.
The last sign of occlusal trauma injury to appear is inflamma-
tory root resorption because the long-term overload will slowly
and gradually, focally necrotize cementoblasts in the root sur-
face; and in these bare areas, this will attract the clasts, thus
initiating the resorptive process.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
12
FINAL CONSIDERATIONS
By disseminating the following information, we must make the
specialties and population aware of the need to examine the
spatial and structural situation of the maxillary and mandibular
canines in all children when they are between eight and ten years
old. In order to prevent problems in the teeth and jaws, the ideal
would also be to evaluate the jaws at the age of about six years.
The methodical and protocol examination of children in the
age group between eight to ten years of age would prevent the
problems associated with eruptive and space disorders of the
maxillary canines. This would lead to great benefits for future
adolescents and adults.
The harmonious smile and the health of the dental arch and
TMJ, associated with the esthetic aspects of a much more beau-
tiful facial ratio, are highlighted by the canines present in the
two corners of the maxillary dental arch. Analyze the faces of
celebrities and acquaintances you consider beautiful: you will
find that the canine will be there, and this is amazing.
When proposing and justifying preventive treatments for eruptive
and space disorders of the maxillary canines, including expanders
and dental traction, these points should be explained to patients
and their guardians in an illustrated way: their receptivity, under-
standing and adherence to treatment will be surprising.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
13
AUTHORS’ CONTRIBUTIONS
Alberto Consolaro (AC)
Mauricio de Almeida Cardoso (MAC)
Renata Bianco Consolaro (RBC)
Raquel Assed Bezerra Segato (RABS)
Conception or design of the study:
AC.
Data acquisition, analysis or
interpretation:
AC, MAC, RBC, RABS.
Writing the article:
AC, MAC, RBC, RABS.
Critical revision of the article:
AC, MAC, RBC, RABS.
Final approval of the article:
AC, MAC, RBC, RABS.
Overall responsibility:
AC.
Patients displayed in this article previously approved the use of their facial and intraoral
photographs.
The authors report no commercial, proprietary or financial interest in the products or
companies described in this article.
Dental Press J Orthod. 2022;27(1):e22ins1
Consolaro A, Cardoso MA, Consolaro RB, Segato RAB — Canines and inflammatory external apical
resorption in healthy maxillary lateral incisors due to occlusal trauma: when to detect the position of
maxillary canines, to prevent it?
14
REFERENCES
1. Ferrandis JFB, Toubia F, Hidalgo LI. El canino incluido: diagnóstico
y su tratamiento. Madrid: MDB, 1990.
2. Becker A. Tratamento ortodôntico de dentes impactados. São
Paulo: Santos, 2004.
3. Consolaro A. Biologia da polpa e do periápice. Maringá: Dental
Press, 2018.
4. Consolaro A. Reabsorções dentárias nas especialidades clínicas.
3.ed. Maringá: Dental Press, 2012.
