Canine impaction pptx - د.زيد الديوه جي

2
Canine Impaction

by

Dr. Zaid Al-Dewachi

Introduction
Canine play an important role in esthetics, being

corner tooth of mouth and function deserves

special attention for its impaction to be properly

diagnosed and managed.

Assesment of

tooth eruption
Tooth
development

Dental age
3/4th root
completion teeth
appears in arch

Nolla and

Moores have
given charts
Normal tooth eruption
6

Impaction
 IMPACTUS (latin origin) = pushed against

 Archer (1975) defines impacted tooth as one

which is completely or partially unerupted and is
positioned against another tooth or bone or soft
tissue so that its further eruption is unlikely.

Impaction

According to Shafer, Hine and Levy,

 Impacted teeth are those which are

prevented from erupting by some
physical barrier in the eruption
path.

 When the crown remains at some

distance from the alveolar crest
after its scheduled eruption time
because of insufficient room or an
ectopic eruption pattern.
8

Impacted canine

 Impaction of maxillary and
mandibular canines is a
frequently encountered
clinical problem.

 Third molars are the most
commonly impacted teeth
and canines stood
second.

ERUPTION OF CANINE

Eruption of canine :

According to Broadbent, AO 1941-

 Development of canine :

• It develops at 4 – 5 months of age between the
roots of deciduous 1st molar.

 Calcification of canine :

• It begins to calcify around 12 months of age.

• Calcification is taking place far above the roots of

deciduous molar, allowing development of the
first premolar between the deciduous molar roots.
11

 At this stage the permanent
canine is located
immediately above both the
erupting first premolar and
the erupted first deciduous
molar.
 As the deciduous teeth
erupts towards the occlusal
plane, the permanent
incisor and canine crypts
migrate forward in the jaws.

 The positional changes

between 8 and 10 years of
age need careful
observation for detection of
12

 During this stage of development the

canine normally migrates buccally from a
position lingual to the root apex of the
deciduous precursor; however, some
canines do not make the transition from
the palatal to the buccal side of the dental
arch and remain palatally unerupted.

 With sufficient increase in the size of the

subnasal area, the maxillary canine
normally moves downward, forward and
laterally away from the root of the lateral
incisor.

 Between 8 and 12 years of age, the 'ugly

duckling' stage, there is insufficient space
at the apical base to permit the axis of the
13

 In the final phase of eruption, canines drive

their way between the lateral incisors and
first premolars, forcing these teeth to
become more upright.
14

Factors governing eruption of

canine

Four factors govern the

eruption of permanent canines
into normal position
1.

2.

3.

4.
Position of tooth bud in bony
crypt

Path of eruption

Shape and position of lateral
incisors

Amount of space available

for canines in the arch
15

Incidence

 Dachi and Howell (1961) reported that the
incidence of maxillary canine impaction is
0.92%, and mandibular canine impaction is
0.35%
 Asians present more of buccal canine
impactions.
 Impactions are twice as common in
females (1.17%) as in males (0.51%).
 Of all patients with maxillary impacted
canines, it is estimated that 8% have
bilateral impactions.

Maxillary canine

Mandibular canine
Buccal
Palatal
Lingual
Buccal
Classification of impacted canine

Impacted canine

Classification of palatally impacted

canine

 Based on two variables:

(1). Transverse relationship of the crown of the

tooth to the line of dental arch which may be

(a) Close

(b) Distant (nearer the midline)

(2). Height of the crown of the teeth in relation

to the occlusal plane which may be

(a) High

(b) Low
20

Group 1

Proximity to the line of arch – close.

Position in the maxilla – low.

Group 2

Proximity to the line of arch – close.

Position in the maxilla – forward , low
mesial to the lateral
&

incisor root.

Group 3

Proximity to the line of arch –

close.

Position in the maxilla – high.
Group 4

Proximity to the line of arch –

distant.

Group 5

Canine root apex mesial to that of lateral

incisor or distal to that of first premolar.

Group 6

Erupting in the line of arch in place and

resorbing the roots of incisors.
23

Classification by ACKERMAN and FIELDS in 1935.

IMPACTED CANINE
Horizontally
Vertically
Palatal
Above
Labial
Below
Mid- alveolar

(With respect to the arch)

(With respect to the apex)
(JCO 1979 DEC)
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Etiology

 Maxillary canines erupt bilaterally where
anterior and posterior regions of maxillary
arch intersect, these osseous structures
have different embryologic origins

 Ant. Maxilla is derived from Ant. Nasal bud

and Post. Maxilla is formed by fusion of
Maxillary buds

 The follicles of maxillary canine are located

at the mesial of the pre maxillary suture
during periods of active growth.

 Any deviation in or disturbance of that

osseous growth can provoke a change in
orientation of canine tooth buds.
26

Etiology of impacted canine

• LOCALIZED

• SYSTEMIC

• GENETIC
27

LOCALIZED

Tooth size- arch length
discrepancies

Failure of the primary canine

root to resorb

Prolonged retention or early

loss of primary canine

Ankylosis of permanent canine

Cyst or neoplasm
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LOCALIZED

Dilaceration of the root

Absence of maxillary lateral

incisor

Variation in timing of lateral
incisor root formation

Iatrogenic factors

Idiopathic factors

SYSTEMIC

Endocrine deficiencies
Febrile diseases
Irradiation
30

GENETIC

Heredity
Malposed tooth germ
Presence of alveolar cleft

32
( Moyers concept summarized by Bishara)

• Moyers say that maxillary cuspid follows a

more difficult and tortous path of eruption
than any other tooth.

• At age of 3 it is high in maxilla and its crown

directed mesially and lingually.

• It moves toward occlusal plane gradually

uprighting itself until it seems to strike the
distal aspect of the root of the lateral incisor.
SAMIR BISHARA. AJO-DO Feb. 1992 & Semin Orthod June 1998

Theories put forth for impacted

canine

 Mc Bridge concept

 Canine is formed high in the anterior wall at antrum,

below the floor of orbit, long tortous path of eruption.

 Tooth have much to travel from floor of orbit to oral
cavity thereby had greater chances of “losing its way”
3

 Becker 1984

 He noted that there appear to be two processes for

palatal displacement of maxillary cuspid
1.

2.
Developmental: due to absence of guidance of
lateral incisor

It relates to more advanced period when tooth

moving down into a narrower part of alveolar
process
35

Vonder Heydt concept

 Total arch length of permanent teeth is initially
established very early in life at the time of eruption of
first permanent molars.

 Canine is larger and later erupting and considering

like a musical chair situation it may get impacted.
36

 Peck and peck concept:

1) Palatally impacted canine is an inherited trait occurs in
combination with tooth agenesis,tooth size reduction,
supernumery tooth and other ectopically positioned
tooth.

2) Bilaterally occuring phenomenon (17%)

3) Females affected more than males (1:3.2)

4) Familial occurrence

So they concluded palatally impacted canine as dental
anomaly having GENETIC ORIGIN.
37

 Guidance theory of Miller:

 Normal eruption: canine usually have a more mesial

development path, which is guided downwards
apparently along the distal aspect of the lateral incisor
roots.

 Miller (1963) and Bass (1967) reported that there

appeared to be an unusually high prevalence of
congenitally missing lateral incisors associated with
palatally impacted canine teeth.
38

 Vincent Kokich 2004

 He said that labial impact of the maxillary canine is
due to either ectopic migration of the canine crown
over the root of lateral incisor or shifting of maxillary
dental midline causing insufficient space for the
canine to erupt.
41

Labial or lingual

malpositioning
of impacted
tooth

Dentigerous
cyst formation
Migration of
neighbouring teeth
and loss of arch
length

Infection

particularly with
partial eruption
Internal resorption or
external root
resorption of impacted
or neighbouring tooth

Referred pain

Shafer et al.
SEQUELAE OF IMPACTED

CANINE

Diagnosis

Inspection
Palpation
Radiograp
hs
44

Inspection

 Non-appearance of

permanent canine clinically
by its eruption age.









Presence of antimere.

Presence of anterior spacing

for a long period.

Persistent median diastema.

Abnormal morphology of
lateral incisor or presence of
peg laterals.

Improper angulations of

Palpation

 Bulge of permanent Canine could be palpated
buccally above the deciduous canine 2-3 yrs
before its eruption.

 It should be palpated deep above attached

gingiva in the sulcus where mucosa reflects.

 Deciduous canine should be checked for

mobility.

 Palpation should be done in abnormal
locations after getting clue from inspection.
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Clinical Assessment of impacted

canine

 Determine patients dental age.

 Assess the primary tooth its absence, colour,
mobility, extent of root resorption.

 Examine the morphology and thickness of

bony contour showing presence of labial or
palatal bulge.

 Examine the cast to determine the arch shape

transverse and sagittal symmetry, intercanine
distance and lack of harmony between tooth
size and arch size.
47

Periapical

Mandibular arch
OPG
Lateral ceph
Extraoral
RADIOGRAPHS

I. Qualitative radiographs

Maxillary arch
Occlusal
PAview
Max. ant. occlusal

Parallax method

C T scanning

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True vertex/occlusal

II. 3-D localisation

Radiographic views at right angle

Occlusal radiograph

 Provides a third i.e. horizontal
dimension.









57x76 mm films are used.

Distoocclusal upper median film.

Central ray of x-ray is placed on
the median sagittal plane and
adjusted at an angle of 60-70 to
long axis of perm. max. canine.

It provides a topographic depiction

of palatal vault aiding in
localization of palatally impacted
tooth.

Does not show exact cross

Occlusal radiograph

Maxillary true (vertex)
occlusal
• X-ray beam runs parallel to
long axis of incisors.
• Possible to get cross section
of anteriors.
• Allows for bucco-lingual
position of impacted
canines or supernumerary
teeth irt to roots of incisors
50

Occlusal radiograph

Maxillary true (vertex)
occlusal Ong’s projection

• Extra-oral technique for

vertex occlusal view

• To increase clarity and

reduce exposure due to use
of intensifying screen
Alternative technique to vertex/true occlusal view
Ong: AJO-DO, Volume 1994 Dec (621 - 626)
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Occlusal radiograph

Mandibular occlusal

900to OP – cross-section of

PM, molar region
1100 to OP – cross-section of
incisor region
5

OPG

 Panoramic radiographs are basic radiograph

for assessment of impacted teeth
•

•

•

•

•
Tooth position whether deep or shallow

General orientation horizontal or inclined

mesially/distally

Relationship with neighbouring teeth

Risk of their transposition

Presence or absence of apical resorption of
roots of adjacent teeth
53

 When mesio distal width of canine crown was

1.5 times larger (i.e. 15% larger) than the
adjacent central incisor, then the canine is
palatally placed

 This is only true in cases where canine should

not be at a higher level
55

56
 Ericson and Kurol in EJO 1988 defined number of
sectors to denote different types of impaction.
i.

ii.
Sector 1: if the cusp tip of the canine is
between the interincisor median line and the
long axis of the central incisor;

Sector 2: if the peak of the cuspid of the canine

is between the major axes of the lateral and
central;

iii. Sector 3: if the peak of the cuspid of the canine

is between the major axis of the lateral and the
first premolar.

 The factors were:

1.

2.

3.

4.

5.

6.

7.
Canine angulation to the midline;

Vertical height of the canine crown;

Antero-posterior position of the canine root
apex;

Canine crown overlap of the adjacent incisor;

Root resorption of adjacent incisor;

Labio-palatal position of the canine crown;

Labio-palatal position of the canine apex.
60

1.Canine angulation to the midline

Grade 1: 0–15°
Grade 2: 16–30°

Grade 3 31°
61

2. Vertical Canine Crown Height

Grade 1: Below the level of the cemento-enamel
junction (CEJ).

Grade 2: Above the CEJ, but less than half way up

the root.

Grade 3: More than half way up the root, but less

than the full root length.

Grade 4: Above the full length

of the root.

3. Position of Canine Root Apex Antero-posteriorly

Grade 1: Above the region of the canine
position.

Grade 2: Above the upper first premolar

region.

Grade 3: Above the upper second premolar

region.
63

4. Canine Overlap of the Adjacent Incisor Root

Grade 1: No horizontal overlap.

Grade 2: Less than half the root width.

Grade 3: More than half, but less

than the whole root width.

Grade 4: Complete overlap of root

width or more.

5. Presence of Root Resorption of the Adjacent

Incisor

The presence or absence of root resorption of the

adjacent upper incisor was recorded as judged
from examination of the OPG, although, a further
50 per cent of patients may have bucco-lingual root
resorption that is not diagnosed by routine
radiography (Ericson and Kurol, 1987).
65

 Conclusion:

The orthodontists’ decision to expose or remove an
impacted upper permanent canine, based on
radiographic information, seems to be primarily
guided by its labiopalatal position and it angulation
to the midline.
66

Lateral Cephalogram

Perapical view

 First and the most simplest view
Advantages
1) Root development, pattern and
integrity
2) Crown resorption
3) Root resorption of adjacent tooth
4) Minimum of surrounding tissue is
exposed which increase
accuracy and resolution.
5) Minimal radiation exposure
Disadvantage
1) 2D picture of 3D object
2) cannot determine bucco-lingual
position of tooth & vertical
position of impacted tooth.
69

70
the canine.
Tube shift technique or Clarke
technique (parallax method)

Principle:

• 2 periapical views of the same object are taken from slightly

different angles which can provide depth to the flat 2-D

picture depicted by each of the films individually.

• Useful in distinguishing the buccal or lingual displacement of

Mesial
angulation
Normal
angulation
Distal
angulation

Procedure:

1.In the periapical film, the X-ray
is taken in the area of interest
with the X-ray beam passing
perpendicular to a tangent to
the line of arch at this point & at
an appropriate angle to
horizontal plane.

2.In the second film, the X-ray

tube is shifted mesially or
distally round the arch but held
at the same angle to the
horizontal plane. The X-ray
tube should describe between
30-450 of an arc of circle whose

72
Result:

• It is based on the SLOB principle.

• If the object has moved on the same side as that

of the X-ray tube it is lingually placed & if it has

moved on the opposite side it is on the buccal

side.

Disadvantage:

In cases when canine is highly placed, and

Periapical film shows no superimposition of canine

with the roots of erupted tooth or when

Vertical tube shift method

 Left canine is highly placed in OPG.

 In IOPA left canine moves towards apical 1/3 of lateral

incisor.
73

CT Scan

 By Ericson & Kurol
 Used to diagnose the exact
position of an impacted tooth.
 Clear serial radiographs may be
taken at graduated depth in any
part of human body in this
method.
 This technique allows the
elimination of superimposition
of other structures.

 It is however rarely used in the
diagnosis of impacted teeth
because of
(1) Large radiation dosage.
74

75
CBCT

 Cone beam

computed
tomography
(or CBCT, also
referred to as C-arm
CT, cone beam
volume CT, or flat
panel CT) is a
medical imaging
technique consisting
of X-ray computed
tomography where
the X-rays are

conventional radiography does

information.
76
not provide sufficient
CBCT

 CBCT is more accurate than

conventional techniques in
localising impacted maxillary
canines.

 CBCT is more reliable than

conventional techniques

 There is no robust evidence
that supports using CBCT as
the first line imaging technique.
We should only use it when

Cone-beam computed tomography vs conventional radiography in visualization

of maxillary impacted-canine localization: A systematic review of comparative
studies. Ehsan Eslami et al. Am J Orthod Dentofacial Orthop 2017;151:248-58

78
 A study was done by Ali Alqerban et al AJODO March
2015, to compare 3D CBCT images of unilaterally
impacted canines with the normal contralateral sides,
and to detect possible radiographic factors involved in
maxillary canine impaction.

 Prediction of the probability of canine impaction based
on CBCT was excellent. The canine angulation to the
lateral incisor on the coronal view, the canine cusp tip to
the occlusal plane on the sagittal view, and the canine
crown position were the strongest predictors based on
the CBCT radiographs and may help orthodontists to
identify the probability of impaction for optimally timing
the intervention.

Cone-beam computed tomographyand the orthosurgical management of impacted

teeth
CBCT imaging can be used to interpret buccolingual
information in detail, to distinguish and define the extent and
depth of root resorption, and to delineate long-axis orientation
of unerupted teeth, including root apex location. It is able to
synthesize traditional panoramic and cephalometric
radiographs. permits oral surgeons to visualize the position
and surgical anatomy of the tooth as it will be seen in the
operating theater and allows orthodontists to plan directional
traction.

Rapid Prototyping

 A new method for diagnosis and treatment
planning of maxillary canine impaction.

 Rapid prototyping' is a group of techniques

used to quickly fabricate a scale model of a
physical part or assembly using three-
dimensional computer aided design (CAD)
data.
Rapid prototyping as a tool for diagnosis and treatment planning for maxillary canine
Jorge Faber, Patrícia Medeiros Berto, and Marcelo Quaresma, AJODO 2006;129:583
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PROGNOSIS

Determining the Prognosis

 Factors influencing the treatment
decision of an impacted canine

Position of canine –

Favorable or Unfavorable
Age of patient
Availability of space
Presence of adequate
width of attached gingiva
VERTICA
L RULE
OF
THIRDS
HORIZONTAL
RULE OF
THIRDS

Treatment alternatives

1. No treatment, if the patient does not desire it.

Since the long term prognosis of deciduous canine

is poor as its root may eventually resorb , it should

be periodically evaluated.

2. Auto transplantation of the canine.

3. Extraction of impacted canine and moving

premolar in its position.

4. Extraction of the canine & posterior segmental

osteotomy to move the buccal segment mesially to