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uropean Journal of Orthodontics 1 0 (1988) 283-295 1988 European Orthodontic Society
Early treatment of pa latally erup ting maxillary canines
by extraction of the primary canines
Sune Ericson and Juri Kurol
Jonkoping, Sweden
S U M M A R Y
The effect of extraction of the primary canine on palatally erupting ectopic m axil lary
canines was analysed. There were 46 consecutive ectopic canines, in 35 individuals, aged 1 0. 0-
13.0 years (mean age 11.4 years) at the t ime of discovery of the ectopic eruption. All cases
showed no or minor space loss. After extraction of the primary canine, the children were
investigated clinically and radiographed at 6-month intervals for up to 18 months.
In 36 of the 46 canines (78 ) the palatal erup tion changed to normal; 23 already show ed
improved posit ions after 6 months and 13 after 12 months. No new cases normalized after 12
months.
We suggest that e xtraction of the primary canine is the treatment of choice in young individu als
to correct palatally ectopically eru pting m axillary canines provided that normal space con dit ion s
are present and no incisor root resorptions are found.
Introduction
The maxillary permanent canine is second only
to the third molar in frequency of impaction,
with a prevalence of approximately 2 per cent
of the population (Thilander and Jakobsson,
1968; Ericson and Kurol, 1986a). The canine is
found palatal to the dental arch in about 85
percent of
the
cases and buccal only in abou t 15
percent (Hitchin, 1956; Rayne, 1969; Ericson
and Kurol, 1987a).
If orthodontic treatment is not started, there
is always a risk of retention and also of resorp-
tion of the roots of the permanen t incisors. Such
resorptions have recently been reported to occur
in 12 percent of cases of ectopic eruption of the
maxillary canines in the age range 10-13 years
(Ericson and Kurol, 1987a). Resorptions may
be found as early as 10 years of age but occur
most often in the age groups 11 to 12 years
(Ericson and Kurol, 1987b).
The most common treatment procedure in
children and adolescents is surgical exposure
followed by orthodontic appliance treatment,
where, as a rule, the prim ary canines are left in
place until the orthodontist has moved the
impacted tooth to this region (Moyers, 1973;
Clark, 1971; Bishara et al., 1976; Hunter,
1983a, b; Fleury et al., 1985). Other proposed
strategies are 1. acceptance, i.e. no treat-
ment, 2. extraction of the malerupting canine,
and 3. surgical repositioning (Richardson and
McKay, 1983).
Several aetiological factors for ectopic canine
eruption have been proposed, and include her-
editary factors, lack of space, persistence of
primary canines, a true ectopic path of eruption ,
reduced root length or aplasia of lateral incisors
(Richardson and McKay,.
.1982;
Jacoby, 1983;
Becker et al.,1984).
Delayed exfoliation of
the
primary canine was
believed by Lappin (1951) to be the principal
aetiological factor and he presumed that it
would be possible to prevent the condition from
occurring in a great many cases, by extracting
the primary canine. This was also suggested by
Miller (1963) and Williams (1981). Berger, in
1943,
stated that widening of the arch in the
premolar region and early extraction of the
primary canines were advisable as precau tionary
measures to prevent incisor root resorptions.
A thorough search of the literature has shown
that sporadic case reports where extraction of
the primary canine has favourably influenced
the future path of eruption have been pre-
sented over the last 50 years (Buchner, 1936;
Ke ttle, 1957; Lind, 1977; Williams,1981;Leives-
ley, 1984). In som e ofthepresented case reports,
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SUNE ERICSON AND JURt KUROL
however, only a slight displacem ent of the canine
is present in the periapical intra-oral radio-
graphs, for example with the crown in a good
position but with an increased mesial angulation
(Kettle, 1957). Other authors have made more
or less casual remarks that extraction of the
primary canine may offer a possibility of correct-
ing impacted canines (Hotz, 1974; Howard,
1978; Silling
et al.,
1979). On the other hand,
there is also a case report in which extraction of
the primary canine did no t affect the eruption
of the permanent canine (Hotz, 1974).
No systematic longitudinal study to evaluate
the corrective effect of prim ary c anine extraction
on the palatally deflected path of eruption of
maxillary canines has been carried ou t, however.
The purpose of this prospective study was to
analyse the effect of extraction of the primary
canine on palatally erupting maxillary canines
in young individuals. It was also considered of
interest to determine when such a corrective
effect of the extraction could be ascertained.
Subjects and methods
Forty-six consecutive ectopic palatally placed
maxillary canines were studied. The children, 14
boys and21girls, were between 10 and 13 years
Figure 1 Orth opan tomo gram (A ), intra-oral axial-vertex radiograph (B) and intra-oral periapical films (C) showing the left
maxillary permanent canine in a true palatal ectopic path of eruption and the right canine with a lingual tendency. At the
start of treatment, the primary canines are present. Normal space conditions. Normalization of the left canine 6 months
after extraction of the primary canine (D).
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Table 1 Distribution according to age
at
th e
time of extraction of the primary canine.
Age-group
10-10.9
11-11.9
12-12.9
Total
Number
of
teeth
17
13
16
46
Percent
37
28
35
100
old
at
the time
of
the discovery
of
the ectopic
position (T able l) and were referred for treatmen t
from the Public Dental Service after the intro-
duction of a digital palpation screening method
(Ericson and Kurd, 1986b). Inability
to
locate
the canine in thenorm al position bydigital
palpation prompted
a
supplementary radio-
graphic examination
of
the canine, where
its
positionwascarefully determined in three plane s
(Ericson and Kurol, 1986a, Fig.
1 .
The eruption angles
and
positions
of the
M e a n
s.d.
Range
degrees)
22.0
11.i
2 - 5 5
d i
m m)
14.7
3.2
9.S 2O.3
Figure2 Mesial inclination (alpha,a) tothe midline a nd
distance dl) to theocclusal line, OL,of the permanent
maxillary canine
in
the frontal plane (orthopantom ogram )
at the start
of
treatment.
Sector
Number
13 11 20 2 0
Sector
Number
8 18 17
Figure 3 Distribution of the 46 maxillary canine s according
to the medial position of the canine crown in sectors 1-5 in
the (A) frontal plane and (B) transverse plane (derived from
orthopantomogram and axial-vertex views)at the startof
treatment.
permanent maxillary canines were determined
as follows:
In the frontal view (orthopantomogram) (A)
the angle of the canine (B) the distance of the
cusp tipto the occlusal line (Fig. 2) and the
medial crown position in sectors1 5(Fig. 3).
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Table 2 Effect of the extraction of the primary canine on the 46 maxillary canines with a palatally ectopic
path of eruption in 35 individuals, 14 boys and 21 girls, aged 10-13 years.
Canine
position
(orthopantomogram)
Sector 1, 2
Sector 3, 4
Total
Total
number
of canines
24
22
46
Improved
after
6 months
19
4
23
position
after
12 months
3
10
13
No change
after
18 months
2
6
S
Worsening
after
18 months
2
2
In the transverse plane (vertex projection) the
position of the crown of the canine relative to
the adjacent lateral incisor and dental arch
was determined from the vertex projection
and the conventional intra-oral projections.
The position of the canine crown relative to
the dental arch was classified as completely
lingual, lingual tendency and correctly pos-
itioned.
In the sagittal plane (lateral head film), the
distances to the occlusal line.
Immediately after diagnosis of the ectopic
palatal path of eruption, th e primary canine was
extracted. The permanent canines were then
followed clinically and radiographically at six-
month intervals up to 18 months for the radio-
graphic procedure, if necessary, and clinically
to full eruption or to the end of necessary
orthodontic appliance treatment. Thus, if a
clearly noticeable improvement of the position
of the maxillary permanent canine was regis-
tered, the radiographic follow-up was termi-
nated at the 6 or 12-month control.
In four of the 46 cases (one boy and three
girls), the lateral incisors already showed root
resorption on the palatal side at start. Two of
the resorptions were superficial and two were
extensive and reached the p ulp. In the latter two
cases, the treatment planning for orthodontic
treatment of their malocclusion included extrac-
tion of maxillary teeth and these two cases were
therefore included in this study.
The maximum width of the dental follicle
of the canine was measured on the intra-oral
periapical radiographs.
All cases had good d ental arches and no space
deficiency was registered after measuring with
sliding calipers. There had been no early extrac-
tion of primary molars in the maxilla.
Conventional statistical methods were used
for calculation of means and standard devi-
ations. Student's /-test was used for parametric
variables and the chi-square test for non-para-
metric variables for the analysis of differences
between the registrations (Nie
et al.,
1975).
Results
The m ain results are presented in ' Tab le 2.
Altogeth er 36 (78 ) of the 46 ectopic canines
showed normalization of the path of eruption
and later clinically correct position at the final
control. For ten teeth no improvement was
registered: seven showed no change at all, one
only slight improvement and two an impaired
position with the crown moving more medially
during the observation period.
ime
factor
Of the36 caseswith normalization and clinically
correct position at the final control, 23 canines
(64 ) already showed improved positions radio -
graphically at the 6-month control, Table 2.
Nine of these had already normalized at this
time (for example, Fig. 1). After 12 mo nth s,
anothe r 13 teeth had normalized and anoth er
14 canines had improved positions and showed
clinically good positions at the 18-month con-
trol. No new cases of improvement occurred
between the 12-month and 18-month obser-
vations.
Medial position {sectors 1-5, Fig. 3
Of the 46 canines, 22 overlapped the adjacent
lateral incisor (in the orthopantomogram) by
more tha n half ofthelateral root, and 14 (64 )
of these normalized (Table 3). Of the 24 canines
which overlapped the lateral incisor root by less
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ECTOPIC MAXILLARY CANINES 287
Table 3 Distr ibution of the medial position of the maxillary permanet canine in
sectors 1-4 in the vertical plane as shown in the orthopantomogram. No teeth
were in sector 5. At the start of treatment, after 12 and after 18 months. Number
and percent.
Registration
At start
(n = 46)
12 months
after
extraction
(n = 37)
18 months
after
extraction
(n = 24)
Medial maxillary canine crown
position in sector
1
n(%)
13(28)
28*(61)
36*(78)
2
n(%)
11(24)
9(20)
2(4)
3.4
n(%)
22(46)
9(20)
8(17)
Total number
46
46*
46*
* 9 canines had normal positions at the 6-month radiographic control and another 13 at
the 12-month control.
Table 4 The distribution of the canine crown position relative to the
midline of the dental arch in the horizontal plane as shown in the axial-
vertex radiogram. At the start of treatment, 12 months and 18 months
after extraction of the primary canine. Number and percent.
Registration
At start
(n = 46)
12 months
after extraction
(n = 37)
18 months
after extraction
(n = 24)
Position
Palatal
n(%)
27(59)
9(20)
8(17)
relative to the dental arch
Palatal
tendency
n(%)
19(41)
15(33)
2(4)
Central
or buccal
tendency
n(%)
22(48)*
36(78)*
Total number
46
46*
46*
* 9 canines had normal positions at the 6-month radiographic control and
another 13 at the 12-month control.
than half of the root at the start of treatment, 3) showed concordant results and will not be
22 (91 ) normalized (Tab le 2, Fig. 4). The reported in detail,
change in medial canine crown position in re-
lation to time after extraction can be seen from Position relative to thedental arch
Table 3, where eight of the ten teeth with no The distribution of the canine crown position
final norm alization belonged to sectors 3 and 4 relative to th e midline of the d ental arch is
and one to sector 2 at the start. The positions shown in Table 4. Of the 27 canines (59 ) in a
of the canines in the vertex projection (Fig. lingual position at the star t of treatm ent (22 in
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SUNE ERICSON AND JURI KUROL
I
Figure 4 Schematic illustration of the norma lization of the
maxillary permanent canine at the control 18 months after
extraction of the primary canines. The figures indicate the
rate of success for the permanent canine positions at the
start of treatment, mesial and distal to the midline of
the lateral incisor in the orthopantomogram.
sectors 3 and 4, and 5 in sectors 1 and 2) only
9 (20 ) remained in this position and no change
could be seen for eight of the canines at the last
control a t 18 mo nths. All the rest normalized
except one, which remained in a slight lingual
position (lingual tendency).This meanscomplete
normalization in 78 of all cases.
Mesial inclination
The d istribution o f the mesial inclination of the
maxillary canines at the start of treatment is
shown in Figure 5. The inclination is approxi-
mately normally distributed. The change after
extraction of the primary canines at the 6-month
and 12-month controls is shown in Table 5.
The dynamic change in position and the mean
difference at the different registrations are
presented. Note the large standard deviations
(Table 5).
Canine vertical distance to the occlusal plane
The distance from the canine cusp to the occlusal
plane (Fig. 2) at the different registrations is
shown in Table 6. The distance at the start of
treatment ranged from 9.5 to 20.3 mm. At that
time, the canines were on average positioned
about 15 mm from the occlusal line in the
orthopantomogram and Table 6 shows the
change during the observation period up to
12 months. The distance as measured on the
lateral head film showed concordant results
compared to Table 6.
1 0 -
I
l l
O*-4* 5*-9*
15'-19* 20T-24 25'-2 9* 3O'-34* 35* -39
#
40* 44* 45'-49' 5O'-S5
Mesial inclination to the midline
orthopantomogram)
Figure 5 Distribution o f the mesia l inclination (degrees) of the 46 maxillary canines to the midline in the orthopan tomo gram
at the start of treatment
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289
Table 5 Mesial inclination (degrees) of the canine to the midline in the
orthopantomogram. Mean va lue and s tandard dev ia t ion a t the d iffe ren t
regis trations and mean difference and level of s ignificance.
Registration
s.d. d s .d .
Level of
significance
At start
(n = 46)
6-month
control
(n = 46)
12-month
control
(n = 37)
22.0
17.9
14.0
11.1
12.5
13.3
4 .1+8.3
p < 0.01
13.3 9.8 + 9.1 p < 0.001
Table 6
Th e dis tance (mm) from the canine cusp to the occlusal plane
in the o r thopantomogram. Mean va lue and s tandard dev ia t ion a t the
different registrations and mean difference and level of significance.
Registration
mean
s.d. d s .d .
Level of
significance
At start
(n = 46)
6-month
control
(n = 46)
12-month
control
(n = 37)
14.7
11.7
9.2
3.2
4.3
5.0
3.0 1.8
5.5 2.7
p < 0.01
p < 0.001
Table 7 Tre atm ent procedures for 10 out of the 46 ectopic maxillary canines where no
impr ovem ent of positi on was registered 12 mo nth s after extraction o f the prim ary canine.
Position in the
orthopantomogram
Change of eruption path Treatment
Orthodontic
impaired surgical fixed appliance ' Extraction
No change position exposure treatment of lateral
Overlapping
less than half
of the
lateral (sectors 1, 2)
Overlapping
more than
half of the
lateral (sectors 3, 4)
Total
6
8
2
2
8
9
8
8
2
2
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SUNE ERICSON AND JURI KUROL
No
normalisation
Ten of the 46 canines showed no change or
an impaired position. The clinical treatment is
shown in Table 7. Nine of these teeth had a tru e
lingual position at the start of treatment (Table
4) and in eight cases the cusp was positioned
mo re medially to the midline of the lateral incisor
in the orthopantomogram. Surgical exposure
and orthodontic fixed appliance treatment was
carried out in eight cases (Table 7). After ortho-
dontic treatment, all canines were in clinically
favourable positions.
Resorptions
In the four cases with resorptions on the root
of the lateral incisor, diagnosed at the start of
treatment, the positions were normal in two
cases, unchanged in one and one canine showed
an impaired position. Three canines were pos-
itioned in sector 3 and one in sector 2 in the
orthopantomogram at the start of treatment.
Two of the resorptions were severe and reached
the pulp at the start of treatme nt. One remained
unchanged and one deteriorated during the
observation period and these two cases are the
extraction cases, where the orthodontic treat-
ment plan included extraction of lateral incisors
as one possibility from the start. No new cases
of resorption were registered during the obser-
vation period.
Dental follicle
The maximal width of the dental follicle of the
maxillary canine, measured on the intra-oral
periapical radiographs, exceeded 3 mm in 13
cases and varied between 1 and 5 mm for the
46 canines. There was no association in those
cases which did not improve related to the size
of the follicle.
Discussion
The effect of extraction of the primary canine
on the palatally deflected path of eruption of
the maxillary canine, is analysed in this report.
To our knowledge, this is the first prospective
longitudinal study where such an effect on pala-
tally erup ting maxillary canines has been shown.
Orthodo ntic textbooks and papers on treatment
of ectopic maxillary canines do not mention this
treatment approach, but there are sparse case
reports in the literature (Buchner, 1936; Kettle,
1957;
Lind , 1977; William s, 1981; Leivesley,
1984). Perhaps extraction of the primary canine
has been considered an 'oddity' and the success
limited to cases with only a minor deflection, as
shown by Kettle (1957).
This study clearly shows that extraction of
the primary canine has a favourable effect on
palatally malerupting maxillary canines. Almost
80 per cent of the cases were corrected due to
the early extraction of the primary canines.
Spontaneous corrections may occur but from
Figure 6 Ectopic palatal eruption o f the right maxillary
canine in a girl aged 12 years 9 months at the start of
treatment. The mesial inclination and palatal position where
the canine crown almost reaches the central incisor can
be seen in the orthopantomogram (A) and axial vertex
projection (B). The radiographs show the improvement of
position and inclination from the start of treatment (C) to
6 months after extraction of the primary canine (D, E).
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ECTOPIC MAXILLARY CANINES
291
clinical experience, it
is
no t likely that ectopically
erupting canines will be spontaneously corrected
to such an extent, especially not those with the
crown in advanced medial positions, as shown
in Figures 2 and 4, Table 2. However, a few of
the canines in the youngest age groups with a
moderate dislocation of the canine might have
corrected spontaneously, as shown by us earlier
(Ericson and Kurol, 1986a). For ethical reasons,
we have not been able to design a study with a
traditional, untreated control group but it is
hardly likely that 22 of 24 canines (92 ) in
sectors
1
and 2 and 14 of 22 (64 ) in sectors 3
and 4 (in the orthopantomogram) would do so.
Theresults will bediscussed withthisassumption
and reservation.
A positive change in the path of eruption
could be observed radiographically in 50 per
cent of the cases, and in some cases (20 )
also clinically, at the 6-month registration after
extraction of the primary canine (Figs.
1
and 6).
At the 12-month con trol, all but nine had normal
or improved positions. If such a change in
eruption is not detectable at that time, a new
decision must be made and some canines posing
a risk of further root resorption of the incisors,
may have to be surgically exposed and treated
with orthodontic appliances, while in most other
cases a further 6 months of observation may be
allowed. If no improvement is detectable at
the 12-month control, we suggest alternative
treatment. If
the
diagnosis is made early accord-
ing to denned criteria i.e. clinical palpation and
if necessary radiographic examination (Ericson
and Kurol, 1986a), there should be enough
time to carry out alternative surgical and/or
orthodontic treatment.
This study has clearly demonstrated the
favourable effect on the maxillary canine even
in very medial positions of the canine crown
(Table 3, Figs. 1 and 6) and up to a mesial
inclination of the canine of 55 degrees to the
midline in the orthopantomogram (Table 6).
Note that canine teeth with similar positions
Figure 7 Palatal ectopic eruption of both maxillary canines in a boy aged 12 years 11 months at the start of tre atme nt
Mixed dentition period. The w idth of the dental follicle exceeded 3 mm fpr both canines.
ID
the orthopantomogram (A) the
mesial inclination to the midline is 31 degrees for the left canine and 27 degrees for the right canine. In the axial-vertex
projection (B) the cusp tips are positioned approximately in the same position lingually to the lateral incisor root Twelve
months after extraction of the maxillary primary canines the orthopantomogram ( Q and axial-vertex projection (D) show
an improved position of the left canine and a slightly impaired position of the right maxillary canine.
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S U N E E R 1 C S 0 N A N D JU R I K U R O L
Figure 8 Girl aged 12 years 8 m onth s at the start of treatment. The right maxillary canine is erupting palatally and the
orthopantomograms, axial-vertex radiographs and intra-oral radiographs show the development from the start (A, C, E) to
12 months after extraction of the primary canine (B, D, F).
and angulations may react differently even in
the same individual, as shown in Figure 7. In
spite of a difference of only four degrees in
mesial angulation and concordant medial and
lingual positions, the left maxillary canine nor-
malized but not the right. Due to the difficulty
in predicting a favourable change of
the
path of
eruption in the individual case, we recommend
radiological and/or clinical supervision at six-
month intervals after extraction of the primary
canine until the permanent canine erupts.
The degree of palatal position at the start of
treatment relative to the dental arch has been
shown to influence the result (Table4).Maxillary
canines with a mod erate lingual path of eruption
normalized more often (90 ) than canines in
true lingual positions (65 ). Again, no reliable
forecast of
success
or failure can be made in the
individual case, although the prognosis for the
treatment on
the
whole
is
very
good.
With earlier
diagnosis according to our earlier recommen-
dations (Ericson and Kurol, 1986b), it may be
possible to achieve even better results as the
canine is then higher up and probably h as a less
deflected path of eruption. Note that one-third
of the patients in this study were between 12
and 13-years-old at the time of referral.
It has often been mentioned that a palatal
path of eruption may be seen in cases where the
primary canine is unresorbed (Dewel, 1949;
Hotz, 1974; Salzmann, 1974). However, it is not
established whether this is a consequence or the
primary cause of the ectopic palatal eruption.
In this study, in individuals aged 10-13 years,
i.e. during a normal eruption period, 21 (46 )
of the 46 primary canines were unresorbed and
25 (54 ) showed various degrees of resorption.
In order to be successful with this procedure
of extracting the prim ary canine,wemust follow
the eruption process radiologically by means of
correct and standardized radiographs. If this is
done, it will be possible to record even slight or
moderate ehanges, as studies of distortion in
rotational panoramic radiography and cephalo-
graphy have demonstrated great tolerance with
respect to angular and vertical distortions
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Figure 9 Girl aged 11 years at the start or treatment (A, C, E) and 12 mon ths later (B, D , F); an impaired posi tion o f the
left maxillary canine is evident in the orthopantomogram, axial-vertex projection and intra-oral radiograph.
(Tronje, 1982; McDavid et
al. 1985;
Ahlqvistet
al.,1986). Based on these reports, and applying
a relative scale for the mesio-distal and bucco-
lingual determinations, it can be claimed that
the registrations in this study have been per-
formed with moderate errors, acceptable for
practical clinical purposes in the everyday clini-
cal situation. Used together, we consider the
methods describe the displaced canine and the
changes in position with sufficient accuracy in
three dimensions and are suitable for this clinical
purpose. Guilford's coefficient of reliability
(Guilford, 1965) was high for all our measure-
ments (Ericson and Kurol, 1988).
In view of the positive results of this study we
suggest that primary canine extraction is the
treatme nt of choice in the age-group 10-13 years
when the permanent maxillary canine has a
palatal ectopic path of eruption. Before the age
of 10, spontaneous correction of potentially
malplaced canines may occur (Ericson and
Kurol, 1986b) and extraction is normally not
indicated unless a very early somatic and dental
development is found. With late diagnosis or
crowding and in cases of resorption or very
horizontal paths of eruption, alternative modes
of treatment should
be
considered, as our experi-
ence of the method in such cases is too small.
Surgical exposure with subsequent orthodontic
appliance treatment will be the main choice in
those cases.
Early extraction oftheprimary canine in order
to correct the malerupting m axillary perman ent
canine has considerable advan tages for the child,
both econom ically and in terms of the discomfort
that result from more traditional treatment ap-
proaches. In fact, periodontal damage to the
ectopic canine after surgical exposure and orth o-
dontic alignment has been reported compared
to control canines (Wisthetal. 1976 a,b; Han s-
son and Under-Aronson, 1972; Boyd, 1982;
Kohavi et al., 1984; Oliver and Hardy, 1986).
Incisor devitalization and some loss of alveolar
bone supp ort may also occur (Proffit and Acker-
man, 4985).
The characteristics of those cases with no
change or an impaired position have to be
further analysed.
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294
SUNE ERICSON AND JURI KUROL
Conclusions and recommendations
It has been clearly shown that extraction of
primary canines in the upper jaw has a favour-
able effect on palataUy erupting maxillary can-
ines in most cases, if this extraction treatment
is
performed in time. Early diagnosis of malerup-
tion is important for success. The ectopic pos-
ition and the path of eruption of the maxillary
canine should preferably be identified before the
age of 11.
When a favourable effect of treatment occurs,
the change in position and in the path of eruption
will be observed at the latest 12 months after
the extraction of the primary canine. If no
improvement can be found at th at time, norma l-
ization is not to be expected and alternative
treatment should be considered. Due to the
great individual variation in the position of the
maxillary canines at the start of treatment and
to some extent also in the response to treatment,
it is not possible to predict success or failure in
the individual case, although the prognosis for
the treatment on the whole is very good. Clinical
and/or radiological controls at six-month inter-
vals are recommended.
In view of the positive results, we suggest that
primary canine extraction is the treatment of
choice in the age-group 10-13 years when the
erupting perm anent m axillary canine has a pala-
tal ectopic path of erup tion. With later diagnosis
or crowding, and in cases of resorption of
the incisor roots or a very horizontal path of
eruption, alternative modes of treatment should
be considered.
Address for correspondence:
Dr Juri Kurol
Department of Orthodontics
The Institute for Postgraduate Dental Education
Jarnvagsgatan 9
S-552
55 Jonkoping
Sweden
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