ORIGINAL ARTICLE

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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, vgkokich@u.washington.edu.mitted, 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

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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

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rightpplians elevCEJreposdonticrootFrom the offices of 5 orthodontic practices, 49nsecutive patients were identified who had at least 1

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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-

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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

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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-

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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.

FERENCES

Bishara SE. Impacted maxillary canines: a review. Am J OrthodDentofacial Orthop 1992;101:159-71.Woloshyn H, rtun J, Kennedy DB, Joondeph DR. Pulpal andperiodontal reactions to orthodontic alignment of palatally im-pacted canines. Angle Orthod 1994;64:257-64.Hansson C, Rindler A. Periodontal conditions following surgicaland orthodontic treatment of palatally impacted maxillary ca-ninesa follow-up study. Angle Orthod 1998;68:167-72.Wisth PJ, Norderval K, Boe OE. Periodontal status of orthodon-tically treated impacted maxillary canines. Angle Orthod 1976;46:69-76.Pearson MH, Robinson SN, Reed R, Birnie DJ, Zaki GA.

xillary caninerown length/wear Recession Color Other

13% 6% 5% 3%4.

5.

Management of palatally impacted canines: the findings of acollaborative study. Eur J Orthod 1997;19:511-5.

6.

7.

8.

9.

al Su38-19rnal o

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 131, Number 4

Schmidt and Kokich 455International Journal of Orthodontics and OrJournal of Orthodontics and Oral Surgery (19Orthodontics (1948-1986), and American JouOrthopedics (1986-present)

1915 to 1932 Martin Dewey1931 to 1968 H. C. Pollock1968 to 1978 B. F. Dewel1978 to 1985 Wayne G. Watson1985 to 2000 Thomas M. Graber

2000 to present David L. Turpinrgery (1936-1937), American47), American Journal off Orthodontics and DentofacialFerguson JW, Parvizi F. Eruption of palatal canines followingsurgical exposure: a review of outcomes in a series of consecu-tively treated cases. Br J Orthod 1997;24:203-7.Kokich VG. Surgical and orthodontic management of impactedmaxillary canines. Am J Orthod Dentofacial Orthop 2004;126:278-83.Silness J, Loee H. Periodontal disease in pregnancy. II. Corre-lation between oral hygiene and periodontal condition. ActaOdontol Scand 1964;22:121-35.Loee H, Silness J. Periodontal disease in pregnancy. I. Preva-lence and severity. Acta Odontol Scand 1963;21:533-51.

10. Fisher L, Van Belle G. Biostatistics: a methodology for thehealth sciences. New York: J. Wiley; 1993.

11. Becker A, Kohavi D, Zilberman Y. Periodontal status followingthe alignment of palatally impacted canine teeth. Am J Orthod1983;84:332-6.

12. Linge L, Linge BO. Patient characteristics and treatment vari-ables associated with apical root resorption during orthodontictreatment. Am J Orthod Dentofacial Orthop 1991;99:35-43.

13. Sameshima GT, Sinclair PM. Predicting and preventing rootresorption: part II. Treatment factors. Am J Orthod DentofacialOrthop 2001;119:511-5.

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