1 - early treatement of palatally erupting canines by extraction of the primary canines - kurol

8/10/2019 1 - Early Treatement of Palatally Erupting Canines by Extraction of the Primary Canines - Kurol

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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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284

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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E C T O P I C M A X I L L A R Y C A N I N E S

285

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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286

SUNE ERICSON AND JURI KUROL

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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288


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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E C T O P IC MA XIL L A R Y C A N IN E S

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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290


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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E C T O P t C M A X I L L A R Y C A N I N E S

293

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


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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1 - early treatement of palatally erupting canines by extraction of the primary canines - kurol

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