-
ORIGINAL ARTICLE
P eaa da pm
AnRh
Int differevis llary cato . Metlat rformeca in thismo d wasim
esultwe or andadjacent to the treated canine. Crestal bone height
was lower at the mesial and distal regions of thelateral incisor
adjacent to the previously impacted canine, and the roots of the
treated canine andadjacent lateral incisor were shorter than those
of the contralateral control teeth.
Twenty-threeortcainanadwit13
Tme
ex
eru
platra
ca
an
difbobe
aPribPrWaRepe-m
Sub088Copdoihodontists and 9 second- and third-year orthodontic
residents could identify the previously impactednine in the
unilateral patients an average of 78.9% of the time, but to a
statistically significant degree66% of all patients. Conclusions:
The overall consequences to the impacted canine of surgical
exposured free eruption are good compared with closed exposure and
early traction, whereas consequences to thejacent teeth,
particularly the lateral incisor, are similar. Future research
directly comparing the 2 methodsh a larger sample and randomization
could yield further insight. (Am J Orthod Dentofacial Orthop
2007;1:449-55)
he palatally impacted maxillary canine is adifficult orthodontic
problem, often requiringsurgical and orthodontic cooperation.
Two
thods of surgical exposure are commonly used: openposure, where
traction is placed after the caninepts freely into the palate, and
closed exposure withcement of an auxiliary attachment, followed
byction of the canine with orthodontic forces.1The effects of
placing traction on an impacted
nine after exposure were studied by Woloshyn et al2d others.3,4
Visual differences, and posttreatmentferences in pulpal status,
attachment level, crestalne height, and probing pocket depth, were
reportedtween previously impacted canines and control ca-
nines not previously impacted.2 In addition, posttreat-ment
differences in root length, attachment level, andcrestal bone
height were found on lateral incisors andpremolars adjacent to the
impacted canines when com-pared with contralateral control lateral
incisors andpremolars.2
The studies involving open exposure with autono-mous eruption
focused mainly on the success of thesurgical procedures. Pearson et
al5 compared simpleexposure and eruption with closed exposure,
bracket-ing, and early traction in 104 consecutively
treatedpatients with palatally impacted canines; they foundthat a
second surgical intervention was needed in15.3% of the open
exposure patients and 30.7% of allpatients exposed and bracketed.
Ferguson and Parvizi6studied the open exposure of 85 palatally
impactedcanines in 72 consecutive patients. They found that84.6% of
the exposures were successful, 10.4% werepartially successful, and
5.1% of the canines required asecond exposure.
Open exposure of a palatally impacted canine withnatural
eruption has several potential advantages, in-
vate practice, Bellingham, Wash.ofessor, Department of
Orthodontics, School of Dentistry, University ofshington,
Seattle.rint requests to: Vincent G. Kokich, 1950 S Cedar St,
Tacoma, WA 98405;ail, [email protected], January
2005; revised and accepted, April 2006.9-5406/$32.00yright 2007 by
the American Association of Orthodontists.
:10.1016/j.ajodo.2006.04.028
449eriodontal response toutonomous eruption, anlignment of
palatally imaxillary canines
drew D. Schmidta and Vincent G. Kokichb
inelander, Wis, and Seattle, Wash
roduction: The purpose of this study was to evaluateual
assessment in patients with palatally impacted maxierupt freely
into the palate, and orthodontically alignederal incisors, canines,
and adjacent premolars were penines and 6 with bilaterally impacted
canines treatednths, and the average posttreatment observation
periopacted canines were not used in the central analysis. Rre
found at the distolingual region of the lateral incisrly
uncovering,orthodonticacted
nces in periodontal status, root length, andnines that were
surgically exposed, allowedhods: Clinical examinations of the
maxillaryd on 16 patients with unilaterally impactedmanner. The
average age was 23 years 72 years 11 months. Data from the
bilaterallys: Differences in probing attachment levelat the
distobuccal region of the premolar
-
clume
dafecex
betome
thi
su
paau
un
ma
American Journal of Orthodontics and Dentofacial
OrthopedicsApril 2007
450 Schmidt and Kokichding fewer subsequent re-exposures,5,6
shorter treat-nt time,7 and improved hygiene during treatment.
To
te, no studies have examined the posttreatment ef-ts of
palatally impacted canines that were surgically
posed and allowed to erupt freely into the palatefore placing
traction. The purpose of this study wasevaluate periodontal, root
length, and visual assess-nt differences between impacted canines
treated ins matter and nonimpacted control teeth.Records from a
sample patient demonstrate the
rgical and orthodontic treatment of a palatally im-cted
maxillary canine with surgical exposure andtonomous eruption (Fig
1). This patient had a Class I
Fig 1. A, Patient had palatally impacted maxillaryautonomously
and reduce time in orthodontic aorthodontic treatment. B,
Mucoperiosteal flap wastill covered in bone. C, All palatal bone
down tounimpeded. D, Hole was made in flap, and it wascanine. E and
F, Canine erupted without orthoocclusal plane, bracket was placed
on crown, andafter appliance removal.crowded malocclusion with a
palatally impactedxillary right cainine. The impacted canine was
sur- coally exposed 4 months before appliance placement,canine was
bonded, and traction was placed 11
nths after the surgical exposure. The total time inhodontic
appliances was 23 months. How does thisthod of treating palatally
impacted canines compareth the traditional method of closed
exposure andmediate traction?
TERIAL AND METHODS
We attempted to follow the study design used byoloshyn et al,2
except that the canines in our studyre treated with open exposure
and autonomousption.
canine. To permit impacted canine to eruptces, impacted tooth
was uncovered beforeated, and it was determined that crown waswas
removed so that the tooth could eruptitioned and sutured over crown
of impactedforces. G, When cusp tip was at level ofwas moved
labially. H and I, Final alignmentgicthemo
ortme
wiim
MA
Wwe
eru
rightpplians elevCEJreposdonticrootFrom the offices of 5
orthodontic practices, 49nsecutive patients were identified who had
at least 1
-
preimthethelowninav
poOnbuas
ua
ginthepre0.2Flomime
na
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proindthesev
Prthede
we
an
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Javne
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we
me
co
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av
tiethean
Twyeimask
Da
ofca
stares
allca
paim
thetheattwe
pawe
bildafrous
bygraticdis
RE
prolenimfroThun
co
Ta
AgTreReAg
American Journal of Orthodontics and Dentofacial
OrthopedicsVolume 131, Number 4
Schmidt and Kokich 451vious palatally impacted canine. Each
previouslypacted canine was exposed and allowed to erupt intopalate
before traction and orthodontic alignment. Of22 patients agreeing
to participate in clinical fol--up examinations, 6 had bilaterally
impacted ca-es, and 16 had unilaterally impacted canines. Their
erage age was 23 years 6.8 months, with an averagesttreatment
period of 2 years 11.5 months (Table I).e patient had been out of
treatment for several yearst had just finished a brief retreat and
was thus labeled1 day posttreatment.Oral hygiene and gingival
inflammation were eval-
ted by using the visible plaque index (VPI)8 andgival bleeding
index (GBI).9 The sulcular depth ofmaxillary lateral incisors,
canines, and adjacent
molars (study teeth) were measured to the nearestmm with a
standardized force probe (0.25 N,
rida Probe, Gainesville, Fla) at the mesiobuccal,dbuccal,
distobuccal, distolingual, midlingual, andsiolingual aspects. The
distance from the cementoe-
mel junction (CEJ) to the gingival margin wasasured to the
nearest 0.5 mm with a Michigan 0be with Williams markings. A
negative recordingicated that the gingival margin was located
apical toCEJ. Two measurements were taken for each site,eral
minutes apart, and the 2 values were averaged.
obing attachment level was calculated by subtractingCEJ-gingival
margin distance from the sulcular
pth.Current periapical radiographs of the study teeth
re used for all measurements of crestal bone heightd root
length. The radiographs and a transparentllimeter ruler for
calibration were digitally scanned800 DPI. The digital image was
then imported,
librated, and analyzed with ImageJ (public domaina
image-processing program available on the Inter-
t at http://rsb.info.nih.gov/ij/). The positions of theJ, the
levels of the alveolar crest, and the root apicesthe study teeth
were evaluated by the second author.G.K.) without knowledge of the
impacted side.ne level was measured as the vertical distance
from
CEJ to the alveolar crest. Bone level was not
ble I. Description of patient sample (n 22)Mean Range
e at start of treatment 17 y 7.2 mo 12 y 8 mo-59 y 6 moatment
period 2 y 9 mo 1 y 4 mo-5 y 2 mo
call period 2 y 11.5 mo 1 day-9 y 6 moe at recall 23 y 6.8 mo 16
y 1 mo-67 yasured at the premolars because the radiographsre not
diagnostic in that area. Root length was beasured as the distance
from the midpoint of a linennecting the mesial and distal CEJ to
the root apex.easurements were made to the nearest 0.01
mm.nmeasurable sites were omitted. Two measurementsre made, several
days apart, and the values wereeraged.
Intraoral frontal photographs of 15 of the 16 pa-nts with
unilaterally impacted canines were taken at
follow-up examinations, coded for identification,d randomly
placed to a PowerPoint presentation.enty-three orthodontists and 9
second- and third-
ar orthodontic residents were asked to identify thepacted canine
in each patient. The raters were alsoed to give a short rationale
for each choice made.
ta analysis
This study was designed as a split-mouth study. Sixthe 22
patients, however, had bilaterally impacted
nines. After data analysis and consultation with atistician, it
was determined that statistically strongerults could be obtained by
not combining the bilater-y impacted canines with the unilateral
canines, be-use this allowed the statistically stronger t test
forired data to be used on the data from the unilaterallypacted
canines.For all data, differences were calculated betweenpreviously
impacted canines and adjacent teeth, andcontralateral control
teeth. Probing pocket depth,
achment levels, crestal bone height, and root lengthsre compared
by using a paired t test for the unilateraltients. The data from
the bilaterally impacted caninesre averaged for each patient so
that each patient withaterally treated canines had only 1 data set.
Theseta were compared with the data from the control teethm the
patients with unilaterally impacted canines by
ing the t test for independent samples.Differences in the VPI
and GBI scores were testedusing the sign test. Rater agreement in
the photo-phic evaluation was assessed with the kappa statis-
, and the results were analyzed with the binomialtribution
test.10
SULTS
No differences in GBI, VPI, pocket probing depth,bing attachment
level, crestal bone height, or rootgth were found in the 6 patients
with bilaterallypacted canines when compared with the control
teethm the 16 patients with unilaterally impacted canines.e
following reported differences are all from theilateral sample when
compared with the contralateralntrol teeth of the same patients.No
differences were found in the GBI or the VPItween the previously
impacted canines and the adja-
-
ce
Ththesiglatthepaco
sigwe
me
imlatthetheaff.03
presh
Ta samp
Scor
GBL 0%C 6%P 0%
VPL 0%C 0%P 0%
Ta betweeinc contro
N
Mea
Lat
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Pre
MB
American Journal of Orthodontics and Dentofacial
OrthopedicsApril 2007
452 Schmidt and Kokichnt teeth and the contralateral control
teeth (Table II).e probing attachment level, the distance
betweenbase of the pocket and the CEJ, was found to be
nificantly greater at the distolingual aspect of theeral
incisors on the impacted side (P .012) and
distobuccal aspect of the premolars on the im-cted side (P .045)
when compared with thentralateral control teeth (Table III). No
othernificant differences in probing attachment levelre
found.Crestal bone height was lower at the distal and
sial sites of the lateral incisor adjacent to thepacted canine
when compared with the contralateraleral incisor. The distal aspect
of the lateral incisor onaffected side was an average of 0.76 mm
lower thancontrol side (P .006); the mesial aspect of the
ble II. Gingival and plaque measurements of unilateralImpacted
side (experimental)
Score 0 Score 1
I measurementsateral incisor 56% 44%anine 56% 44%remolar 56%
44%
I measurementsateral incisor 94% 6%anine 88% 12%remolar 94%
6%
ble III. Mean differences in probing attachment levelisors and
premolars (impacted side) and contralateral
Impacted side
Mean (mm) SD
eral incisor MB 0.53 0.50B 0.60 0.47DB 0.51 0.60DL 0.73 0.59L
0.45 0.61ML 0.35 0.49
nine MB 0.64 0.64B 0.40 0.45DB 0.53 0.82DL 0.65 0.71L 0.67
0.92ML 0.41 1.17
molar MB 0.60 0.47B 0.50 0.42DB 0.63 0.66DL 0.04 0.55L 0.22
0.46
, Mesiobuccal; B, buccal; DB, distobuccal; DL, distolingual; L,
lingected lateral was an average of 0.29 mm lower (P 4) than the
control side (Fig 2).
ratThe roots of the previously impacted canine andjacent lateral
incisor were significantly shorter thanse of the control canine and
lateral incisor. Theviously impacted canine was an average of 1.08
mm
orter (P .025) than the control canine; the adjacenteral incisor
was an average of 1.87 mm shorter (P ) than the contralateral
control lateral incisor (Fig 3).The photographic evaluation surveys
were assessed2 ways. Each rater was scored individually as a
rcentage of the correctly identified impacted canines,d the
scores were averaged. Orthodontists andidents could identify the
previous unilaterallypacted canine an average of 78.8% of the
time.e mean average of the orthodontists alone was%; the mean
average of the residents alone was%. The overall kappa statistic, a
measurement of
le (n 16)Nonimpacted side (control)
e 2 Score 0 Score 1 Score 2
50% 50% 0%63% 37% 0%56% 44% 0%
100% 0% 0%94% 6% 0%94% 6% 0%
n previously impacted canines and adjacent laterall teeth
(nonimpacted side) (n 16)onimpacted side
n (mm) SD Mean difference P value
.58 0.61 0.05 NS
.49 0.40 0.11 NS
.51 0.41 0 NS
.28 0.55 0.45 .012
.59 0.60 0.14 NS
.43 0.48 0.08 NS
.63 0.28 0.01 NS
.40 0.46 0 NS
.28 0.37 0.25 NS
.63 0.48 0.02 NS
.65 0.53 0.02 NS
.56 0.43 0.15 NS
.60 0.53 0 NS
.37 0.47 0.13 NS
.35 0.64 0.28 .045
.38 0.52 0.34 NS
.48 0.54 0.26 NS
, mesiolingual; NS, Not significant.lat.01
inpean
res
imTh8174adtho
00000000000000000
ual; MLer agreement, was 0.58.The surveys were also scored as a
percentage score
-
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Figpesid
Root
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Figtee(no
American Journal of Orthodontics and Dentofacial
OrthopedicsVolume 131, Number 4
Schmidt and Kokich 453raters correctly identifying the
previously impactednine for a particular patient. Agreement of 22
of the raters was significant to the 0.05 level.10 Ten of the
canines, or 66%, were correctly identified to anificant level.
In 5 of the 15 patients, the raters couldt identify the previously
impacted canine to a signif-nt level.The reasons for identifying
the impacted canine
re tabulated into 7 categories: torque, gingiva (gin-al
attachment/gingival margin), alignment, crowngth/wear, recession,
color, and other. The reasonsen in identification of the previous
palatally im-
cted maxillary canine are summarized in Table IV.
SCUSSION
This study was designed to be compared with the94 study of
Woloshyn et al.2 Those authors exam-
0
0.5
1
1.5
2
2.5
3
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MesialCanine
*DistalLateral(p
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2.
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%
American Journal of Orthodontics and Dentofacial
OrthopedicsApril 2007
454 Schmidt and Kokichisor. Similarly, in agreement with other
studies,3th studies reflect attachment loss distal to the
affectederal incisor in the crestal bone height measurements;th
studies showed approximately 0.8 mm of meanne height loss when
compared with the contralaterale. Our study also showed a small
amount of crestalne loss on the mesial aspect of the affected
lateralisor, a unique finding compared with Woloshyn et and other
studies.3,11This study agrees with findings by Woloshyn et al2
d others,12 showing root resorption of the lateralisor on the
impacted side. Woloshyn et al found aan root loss of 1.33 mm, and
we found a mean roots of 1.87 mm. Woloshyn et al also showed that
rootorption was associated with the impacted-side pre-lars, but our
study shows mean root loss on theviously impacted canine but not
the adjacent pre-lars. Perhaps more force is transmitted to the
pre-lar mechanically through traction than when the
nine is allowed to freely erupt, resulting in more rootorption
in the premolar area with early caninection. The increased root
resorption in the canineowed to freely erupt could be a result of
the longtance the root must travel when the tooth erupts into
palate.13 It is also possible that the affected caninesk the
developmental root length of normally erupting
nines, and that the differences are a result of devel-mental
differences rather than resorptive differences.We found that
orthodontists and second- and third-
ar orthodontic residents could correctly identify theviously
impacted canine an average of 78.8% of thee, a similar rate to that
found by the 2 senior authorsthe study of Woloshyn et al (74.2%).2
When ana-ed by individual patient, however, orthodontists andidents
could definitively identify the correct canineonly 67% of the
patients to a 0.05 level of signifi-
nce. The kappa statistic, a value estimating theportion of
agreement between raters after account-
for chance, was 0.58. The kappa statistic ap-aches 1 when there
is perfect intrarater reliability
d moves toward 0 when there is no agreement othern what would be
expected by chance alone. A kappa0.58 indicates moderate intrarater
agreement in
nine identification.The 3 most common reasons given for
identifying
ble IV. Reasons given in identifying previously impactTorque
Gingiva Alignment
of reasons given 28% 27% 17%previously impacted canines were
torque, gingiva,d alignment. Differences in torque, noted in 28%
ofreasons, reflect the difficulty in moving the root oftreated
canine buccally enough with orthodontic
pliances to mimic the contralateral canine eminence.ngiva,
comprising 27% of the reasons, indicates arceived difference in
amount of attached gingivaen compared with the contralateral tooth,
or aference in the relative heights of the gingival mar-s.
Alignment, a reason given 17% of the time,ects either a tendency
toward relapse of the treated
nine or a lack of complete alignment of the impactednine after
orthodontic treatment.
NCLUSIONS
Treating palatally impacted maxillary canines withen surgical
exposure, natural eruption of the canine,d orthodontic alignment
has minimal effects on theriodontium. In this study, the roots of
the impactednine and the adjacent lateral incisor were
slightlyorter than those of the contralateral control teeth,
and
significant pulpal changes were identified. Visualferences were
present in the previously impactedth when compared with the
contralateral control
nine. The overall consequences to the impactednine with this
technique seem better than with closedposure and early traction of
impacted canines. Con-uences to the adjacent teeth, particularly
the lateralisor, seem quite similar with both techniques.
Futureearch directly comparing the 2 methods with a largerple and
randomization could yield further insight.
We thank the offices of Drs Richard T. Jones,uglas J. Knight,
Vincent O. Kokich, and Peter A.apiro for their assistance in
gathering the sample.
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al Su38-19rnal o
American Journal of Orthodontics and Dentofacial
OrthopedicsVolume 131, Number 4
Schmidt and Kokich 455International Journal of Orthodontics and
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Editors of the International Journal of Orthodontia
(1915-1918),International Journal of Orthodontia & Oral Surgery
(1919-1921),International Journal of Orthodontia, Oral Surgery and
Radiography (1922-1932),International Journal of Orthodontia and
Dentistry of Children (1933-1935),
Periodontal response to early uncovering, autonomous eruption,
and orthodontic alignment of palatally impacted maxillary
caninesMATERIAL AND METHODSData analysis
RESULTSDISCUSSIONCONCLUSIONSAcknowledgmentREFERENCES