Zainab F.doc
J Bagh College Dentistry Vol. 25(2), June 2013 CBCT analysis
Oral Diagnosis 114
CBCT analysis of impacted maxillary canines
Zainab H. Al-Ghurabi, B.D.S., H.D.D., M.Sc. (1)
ABSTRACT
Background: This study designed to shade light on the important role of CBCT in accurate localization of the
impacted maxillary canines.
Materials and method: Fifty two unilateral and bilateral impacted maxillary canines from 30 patients (24 females and
6 males) were evaluated by a volumetric 3D images obtained from cone beam CT. All samples attended to the
specialist health center of dentistry in Al-Sadder City referred to CBCT by oral surgeons or orthodontists to detect the
exact position of impacted upper canine in cases when there was no bulging buccally or palatally which aids to
detect the exact position.
Results: Mesio-palatal angulations had the highest rate (63.5%) followed by mesio-labial (19.2%), vertical (labial)
(9.6%), disto-palatal (5.8%) and disto-labial (1.9%). The relation between impacted canine and the adjacent teeth
regarding to the attachment was significant only with lateral incisor. No cases of root resorption of the adjacent
teeth were recorded. Bilateral impacted teeth were found in 22 patients which is highly significant (especially in
females), while unilateral impaction was found only in 8 patients especially in females. Impacted canine was more
prominent in female whether unilateral or bilateral.
Conclusions: CBCT imaging of impacted canines can show the following: presence or absence of the canine,
angulations of the long axis of the tooth, relative labial and palatal positions and proximity to adjacent teeth. In short,
CBCT imaging is clearly advantageous in imaging and management of impacted canines.
Key words: CBCT, impacted maxillary canine. (J Bagh Coll Dentistry 2013; 25(2):114-118).
INTRODUCTION
Orthodontic treatment of impacted maxillary
canine remains a challenge to today’s clinicians.
The treatment of this clinical entity usually
involves surgical exposure of the impacted tooth,
followed by orthodontic traction to guide and
align it into the dental arch. Bone loss, root
resorption and gingival recession around the
treated teeth are some of the most common
complications (1). Early diagnosis and intervention
could save the time, expense and more complex
treatment in the permanent dentition.
Tooth impaction can be defined as the
infraosseous position of the tooth after the
expected time of eruption, whereas the anomalous
infraosseous position of the canine before the
expected time of eruption can be defined as a
displacement. Most of the time, palatal
displacement of the maxillary canine results in
impaction (2).
Accurate diagnostic imaging is an essential
requirement to derive the correct diagnosis and
optimal treatment plan, as well as monitor and
document the treatment progress and final
outcome (3).
Two-dimensional (2D) diagnostic imaging,
including traditional radiographs, cephalometric
tracings, photographs and video imaging, has
been a part of the orthodontic patient record for
decades. The limitations in analysis of these
imaging modalities are well known, and include
magnification, geometric distortion,
superimposition of structures, projective
displacements (which may elongate or foreshorten
(1) Assistant Lecture, Department of Oral Diagnosis, College of
Dentistry, University of Baghdad.
an object's perceived dimensions), rotational
errors and linear projective transformation (4,5)., in
contrast, three-dimensional (3D) imaging allows
for the evaluation and analysis of “the anatomical
truth (6,7).
More recently, this high-resolution imaging
technique has gained importance in diagnosing
dental-associated diseases of the mandible and
maxilla. CBCT (3D) offers super visualization of
impacted teeth and can help the clinician to plan
his treatment preoperatively or prior to
orthodontic therapy (Figure 1) (8-10).
Dental CT investigations can be performed
either on CBCT (cone beam computed
tomography) or multi-detector spiral CT scanner.
The device should be capable of performing high-
resolution scans with a small focal spot and
acquiring thin slices of 1.5 mm or less. The
position of the tooth within the alveolar crest as
well as the relation to surrounding structures is
clearly disclosed.
Impacted and transposed teeth are possibly the
most common reason for use of dental CT
imaging in orthodontics. The information derived
can enhance the ability to localize impacted teeth,
identify pathological conditions and root
resorption, help plan surgical access and bond
placement, and define the optimal and most
efficient path for extrusion into the oral cavity that
avoids or minimizes collateral damage (2).
Furthermore, CBCT scans can provide
diagnostic information on roots of the adjacent
teeth that are in close proximity to the impacted
tooth or in its traction path that can be moved
proactively and avoid causing damage. Another
advantage of dental CT over routine radiographs
J Bagh College Dentistry Vol. 25(2), June 2013 CBCT analysis
Oral Diagnosis 115
includes the accurate measurement of the
impacted tooth to aid in determining and
developing the space needed for the tooth.
This study designed to shade light on the
important role of CBCT in accurate localization of
the impacted maxillary canines.
SUBJECTS, MATERIALS AND
METHOD
The study sample comprised 30 patients with
(52) impacted maxillary canines, (24 females)
with 44 impacted canines and (6 males) with 8
impacted canines, with an age ranged from 10 to
20 year and the age distribution in relation to the
gender clear in table (1). These patients were
referred to Specialist center of Al-Sadder City for
localization of these impacted canines, using
Kodak 9500 CBCT. The investigation performed
with 90 kV, 10 mA, 1mm slice thickness and 10.8
seconds time of exposure. The images were
collected from the workstation of the CT unit.
Before investigation every patient asked about
name and age then asked the patient to remove
any metal object, to avoid distortion, and not to
move or breathe while exposure performed. The
plane for primary reconstruction is aligned
parallel to the occlusal plane. The reconstruction
volume ranges within many axials for inspection
of the relationship between the impacted canines
and peripheral bony and dental structures.
Imaging data were analyzed with the software
provided by the manufacturer.
The following records were evaluated in the
CT workstation for every subject: (1) The three
dimensional variations of impaction—in each
case, the vertical inclination was considered first,
followed by the mesio-distal migration and bucco-
palatal crown location (2) Contact of impacted
canine to the adjacent incisor.
After that, on the work station, each case
diagnosed with 3D volumetric image (as shown
in fig 2) to diagnose the impacted canine from all
directions, in addition to this volumetric images,
all of the samples diagnosed with multiple axial
slices to show its exact direction and its relation
to labial or palatal alveolar bone, (as shown in
Figure 2-a) and diagnosed with sagittal slice to
show its position laterally and assess the amount
of bone that covered the impacted tooth labially
and palatally and its relation with adjacent
structure (as shown in Figure 2-b,c). Coronal slice
also used to detect canine position antero-
posteriorly as shown in Figure 2-d).
RESULTS
Regarding the site of impacted canine, it was
found that the ratio of bilateral impacted upper
canine was (84.7%), (which is highly significant)
than the ratio of unilateral impacted upper canine
(15.3%) (which is non-significant), as shown in
table 2. As clear in the same table the female ratio
is higher in bilateral (77%) than unilateral (7.7%)
and the ratio of impacted upper canine in females
was higher than males.
As shown in table 3, according to the direction
of impacted upper canine, the percentage of
palatal direction was (69.3%) higher than the
percentage of labial direction (30.7%).
According to the canine angulation, the mesio-
palatal angulations was higher among the others
(63.5%), as clear in this table only this angulation
was significant, followed by mesio-labially
(19.2%), vertico-labial (9.6%), disto-palatally
(5.8%) and the lowest percentage was disto-
labially (1.9%).
According to the relation of impacted canine
with the adjacent teeth, it was found that the
highest rate of attachment with impacted canine
was the lateral incisor (88.46%) which was
significant.
DISCUSSION
Peck et al. (13) stated that the etiology of
palatally impacted canines is genetic in origin,
while the etiology of labially impacted canines is
due to an inadequate arch space.(11-13).
In this study, it was found that, bilateral
impacted canine more frequent than unilateral and
this may be related to genetic factor and this result
come in accordance with many studies (11,12,15-17).
Female ratio of impacted canine was higher than
male generally and in bilateral impaction
especially, this result comes in agreement with
other studies (13,14).
In the current study, impaction was
summarized into 4 variations, with an aim of
convenient description of the complex locations
of impacted canines. Mesio-palatal impacted
canines were the most common representing
(63.5%) of the study sample, followed by mesio-
labialy (19.2%), vertico-labialy (9.6%), disto-
paltaly (5.8%), and disto-labialy (1.9%)
respectively, while there is no vertico-palataly
case in this study. From these results, it could be
concluded that, the palatal direction more than
buccal direction and this come in confirm with
many studies (14-17) who stated that the palatal
direction of impacted upper canine is twice or
more than labial direction while disagree with
Peck et al. (13), who stated that, in Asian the
J Bagh College Dentistry Vol. 25(2), June 2013 CBCT analysis
Oral Diagnosis 116
impacted canine usually labial, and this may be
due to different race and sample size.
Relation between the impacted canine & the
adjacent teeth is very important point because this
impacted canine may cause resorption to the
adjacent teeth when its direction or angulations
very near or overlap these adjacent teeth.
However in the present study there was no
resorption in the adjacent teeth but there was
touch them (resorption of palatal or labial bone),
the most teeth that touched with impacted canine
were central and lateral incisors when its
angulations mesially and vertically (palatally or
labial direction) and 1st and 2nd premolars when its
angulations distally (palatal or labial direction).
In this study only lateral incisor was
significantly touched with impacted canine
(without resorption of its root) and this may be
regarding to its pathway of eruption, although the
remaining teeth touched to the impacted canine
but it’s not significantly as with lateral incisor.
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Table 1: Distribution of maxillary canines according to sex and age in a sample of 30 patients
Genders No. of patient
Age
Range Mean ± SD
Females 24 10-15 12.5 ± 2.53
Males 6 15-20 17.01 ± 2.73
Total 30 10-20 13.3 ± 3.06
Table 2: Distribution of impacted canine according to the side involvement in relation to the
gender
Genders
Bilateral Unilateral Total
No. of
patients
No. of impacted
canine
No. of
patients
No. of impacted
canine
Females 20 40 (77%) 4 4 (7.7%) 44 (84.7%)
Males 2 4 (7.7%) 4 4 (7.7%) 8 (15.3%)
Total 22 44 (84.7%) 8 8 (15.3%) 52 (100%)
P-value
0.005
P<0.05
S
0.368
P>0.05
NS
J Bagh College Dentistry Vol. 25(2), June 2013 CBCT analysis
Oral Diagnosis 117
Table 3: Statistical distribution of impacted canine according direction and angulations of 52
impacted teeth
Palataly labially
Total
P
value No. of cases Mesio-palatally Disto-palatally Mesio-labially Disto- labially Vertical-labially
Females 30 (68.2%) 3(6.85%) 8 (18.2%) 1 (2.3%) 2(4.5%) 44(100%) 0.022 S
Males 3 (37.5%) 0(0%) 2 (25%) 0 (0%) 3(37.5%) 8(100%) 0.028 S
Total 33 (63.5%) 3(5.8%) 10 (19.2%) 1 (1.9%) 5(9.6%) 52(100%) 0.024 S
33 (69.3%) 16 (30.7%)
P value 0.0137 Sig. -------
0.13
Ns. ------
0.137
Ns.
0.016
S
Signi
ficant
Table 4: Contact relationship between impacted canine and adjacent teeth
Central incisor Lateral incisor 1st premolar 2nd premolar
Type of
contact No touch Touch
No
touch touch Touch
No
touch Touch
No
touch
Mesio-palataly 9 24 - 33 - - - -
Mesio-labialy 7 3 - 10 - - - -
Disto -palataly - - 2 1 - - -
Disto-labialy - - - - 1 - - -
Vertico-labialy - - 3 2 - - - -
Total 16 (30.76%)
27
(51.92%)
5
(9.61%)
46
(88.46%)
1
(1.92%) -- - -
P value 0.285 NS
0.283
NS
0.288
NS
0.038
S
0.157
NS _ _ _
Figure 1: 3D volumetric image clear bilateral labial directed upper impacted canine in the right
and left side for the same patient.
J Bagh College Dentistry Vol. 25(2), June 2013 CBCT analysis
Oral Diagnosis 118
A B
Axial Sagittal
C D
Sagittal Coronal
Figure 2: Multidetcter slices clear impacted upper canine