pi is 0889540606013230

CLINICIANS CORNER

E ctia atao tsYo i,c andSeo

Pla simpltee rusionsp ric chwit sure, btee chieveret hod D

Iex

payetioadtioa m

mo

linram

bratioclean. Furthermore, with lingual brackets, it is likelythat the anterior teeth will lose their proper inclinationsduring the retraction period.

era

visan

appu

teearc

intniqfriforrea

prothadeincbrama

Ap

To splint 6 teeth into 1 unit and retract them on thepalatal side, 0.9-mm stainless steel wire was bent

Froof DaProbThcSedClSupRepDen749Sub088CopdoiThe appliance introduced here was designed for sev-l purposes. The first was to reduce the patients time inible appliances. This is accomplished by retracting 6terior teeth by splinting on the lingual side withoutpliances during the initial retraction period. The secondrpose was to obtain the desired type of movement of

according to the lingual surface of the 6 maxillaryanterior teeth and the contour of the palatal slope in thecanine area. It was then soldered with metal mesh. Fourorthodontic mini-implants (Orlus, Seoul, Korea), 2 mmin diameter and 7 mm in length, were implanted2 inthe midpalatal area, 10 mm apart, and the other 2 in theinterproximal alveolar bone, between the maxillarysecond premolar and the first molar of each side.

The mini-implant-supported transpalatal arch(TPA) was made with 0.9 mm stainless steel wire. (Thebent TPA has a hook to which elastic chains areconnected to give the retraction force.) The middle partof the bent wire was soldered with metal mesh (3.0 12.0 mm) and then bonded to the midpalatal mini-implants. The mini-implant-supported TPA was used asindirect absolute anchorage on the palatal side (Fig 1).

The type of movement of the 6 maxillary anteriorteeth (controlled tipping, bodily movement, root move-

m the Department of Orthodontics, Oral Science Research Center, Collegeentistry, Yonsei University, Seoul, Korea.fessor, BK 21 project.ird-year resident.cond-year resident.inical lecturer.ported by a grant from the BK 21 project.rint requests to: Young-Chel Park, Department of Orthodontics, College oftistry, Yonsei University, 134 Sinchon-dong Seodaemun-gu, Seoul 120-, Korea; e-mail, [email protected], April 2005; revised and accepted, May 2005.9-5406/$32.00yright 2007 by the American Association of Orthodontists.

:10.1016/j.ajodo.2005.05.051

537sthetic segmental retranterior teeth with a palrthodontic mini-implanung-Chel Park,a Yoon-Jeong Choi,b Nak-Chun Choul, Korea

cing orthodontic mini-implants allows clinicians to useth. This usage is reported here in a patient with lip protlinted on the lingual side and retracted by an elastomehout the use of an archwire or brackets. After space cloth. The desired movement of the anterior teeth was araction force and adjusting the line of force. (Am J Ort

n most orthodontic patients, including those withsevere skeletal disharmonies, esthetic improve-ment is a primary treatment objective. Premolar

traction is a common treatment method, especially intients with lip protrusion. It usually takes 1.5 to 2ars to treat these patients, unless they undergo addi-nal surgery to facilitate the extraction treatment.1-4 Inults who desire esthetic improvement, the long dura-n of treatment when fixed appliances must be worn is

ajor deterrent. This has led to the development ofre esthetic appliances, such as ceramic, resin, andgual brackets, but they have some limitations. Ce-ic and resin brackets are still visible, and lingual

ckets make it difficult for doctors to see the opera-n field directly and for patients to keep the areaon of maxillaryl appliance and

Jong-Suk Leed

e and esthetic appliances to retract anteriorand mild crowding. The anterior teeth wereain connected to orthodontic mini-implantsrackets were bonded for detailing individuald by changing the application point of theentofacial Orthop 2007;131:537-44)

th by using orthodontic mini-implants and a segmentedh technique. Since the segmented arch technique wasroduced by Burstone,5,6 several cases with this tech-ue have been reported.7-9 Although this technique is

ctionless and allows easy control of the moment-to-ce ratio, the need for reinforcement of anchorage in thective unit makes these appliances complicated. Theseblems can be overcome by orthodontic mini-implantst simplify the appliance.10-12 The final reasons for the

velopment of the appliance described here were torease patients comfort levels compared with lingualckets and to allow oral hygiene to be more easilyintained.

pliance fabrication

me

pamigrares

ce

bo(Fimme

ma

leninttherefdeteema

tip

DUela

bopaimso

wa

alvwi

Figpla

orthoal surast sh

Figteewa

American Journal of Orthodontics and Dentofacial OrthopedicsApril 2007

538 Park et alnt) can be changed by shifting the line of force thatsses through the palatal lever arm and the hook of theni-implant-supported TPA.13,14 In a lateral cephalo-m, the retraction line passing through the center ofistance of the 6 maxillary anterior teeth (7 mm in the

rvical direction from the interproximal alveolarne15,16) and paralleling the occlusal plane was drawnig 2). The perpendicular length from the mini-plants on the midpalate to the retraction line wasasured, and the mini-implant-supported TPA wasde the same height as the perpendicular length. Thegth from the cingulum of the canine to the point ofersection of the retraction line and the soft tissue of

palatal slope was measured. This was used as theerence length when the palatal lever arm length wastermined according to the desired movement of theth (Fig 3). In this case, the palatal lever arm wasde shorter than the reference length because lingualping was required.The clear lever arm was made by cutting 1.0 mm

Fig 1. Appliance fabrication procedures. A, TwoB, Mesh-soldered lever arm was bonded to lingubonded to mini-implants. C, Sagittal section of c

2. Line of force and center of resistance of anteriorth in lateral cephalogram of patient when appliances set up.RAN (Scheu-Dental, Iserlohn, Germany), a hard,stic, 1 mm-thick transparent acrylic plate, that was

an

dended to the labial surface of the canine. The line thatssed between the clear lever arm and the mini-plant in the buccal interproximal bone was adjustedthat it was parallel to the occlusal plane. This lines about 4 mm in the cervical direction from theeolus; the maxillary anterior teeth would be retractedth lingual tipping, as on the palatal side.

se study

A 23-year-old woman came to our clinic complain-of lip protrusion and mandubular anterior crowding

igs 4 and 5). When her lips were closed, hyperactivitythe mentalis muscle was observed. In the lateralfile, an acute nasolabial angle and protrusive upper

d lower lips were seen. The maxillary dental midlines congruent with the facial midline, but the mandib-r dental midline was 1.0 mm off to the right side.ere were no symptoms of temporomandibular jointorders.In the intraoral examination, a Class I canine andlar relationship was seen on both sides. In the cast

3. Method used to determine height of mini-im-nt-supported TPA.

dontic mini-implants applied at midpalate.faces and mini-implant-supported TPA wasowing line of retraction force.Ca

ing(Fofproan

wa

ulaThdis

moalysis, 1.0 mm of crowding in the maxillaryntition and 5.0 mm of crowding in the manidibular

deaddiave

preortch

wa

we

aginv

an

bo

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 131, Number 4

Park et al 539ntition were measured. Overjet and overbite wereequate, and the curve of Spee was moderate. Thegnosis was skeletal Class I occlusion with bial-

olar protrusion (Table). Extraction of the 4 firstmolars was planned, and it was decided to usehodontic mini-implants for reinforcement of an-orage and simplicity of design.

For esthetic treatment, the appliance described earliers used in the maxilla. In the mandible, ceramic bracketsre bonded because of moderate crowding. The patientreed to the treatment plan and was satisfied with theisibility of the appliance after bonding.The mesh-soldered lever arm for the 6 maxillary

Fig 4. Pretreatment extraorterior teeth that had been made on the cast wasnded with Transbond resin paste (3M Unitek, Mon-

ulealsia, Calif), and the mini-implant-supported TPA onmidpalatal area was bonded with BISFIL core resin

isco, Schaumburg, Ill). The surface of the mesh thatuld be bonded to the teeth was micro-etched withdblast to increase bonding strength. The clear lever

was bonded with Transbond resin to the labialrface of the maxillary canine that had been previouslyhed (Fig 6).The retraction force (about 150-200 g per side) wasvided to the maxillary anterior segment by anstomeric chain. Although the rate of space closure isnificantly greater and more consistent with nickel-nium closed-coil springs than with elastic mod-

intraoral photographs.rov

the(Bwo

san

arm

su

etc

proelasigtita

al ands,17 elastic chain was used for esthetic reasons ando to facilitate proper oral hygiene.

folteepothrma

apsu

dibme

cu

oc

10ali

an

mo

mo

RE

mo

ov

sio

truco

thefirjaw

FigboB,

Ta

SNSNANSNMaIMMaMaNaUpLo


540 Park et alThe mandibular canines were retracted partiallylowed by the en-masse retraction of the anteriorth by sliding mechanics. The occlusion of thesterior teeth was maintained in a stable positionoughout the treatment period, even though thexillary posterior teeth were not included in the

pliance during space closure. As seen in theperimposition of the mandible (Fig 7), the man-ular first molar was uprighted and barely movedsially after treatment because of the compensating

rve of the mandibular archwire and the stableclusion from the beginning of treatment.

After the maxillary extraction space was closed for

Fig 5. Pretreatment radiographs.months, the appliances were bonded for leveling andgnment of mild crowding, correction of root axes, lard bite seating (Fig 8). Treatment was finished 6nths after bonding, for a total treatment time of 16nths (Figs 9 and 10).SULTS AND DISCUSSION

After treatment, the patient had a Class I canine andlar relationship, a consonant midline, a normal

erjet and overbite relationship, and a stable occlu-n.The acute nasolabial angle was increased, the pro-

sion of the upper and lower lips to the E-line wasrrected, and a harmonious profile was achieved. In

cephalometric analysis, these changes were con-med, and the protrusion of the alveolar bone of each

was decreased (Table).

6. Intraoral photographs showing A, clear lever armnded to labial surface of maxillary canine andpalatal lever arm and mini-implant-supported TPA.

ble. Cephalometric measurementsPretreatment Posttreatment

A angle () 84.0 84.1B angle () 81.1 80.8B angle () 2.9 3.3to mandibular plane () 21.3 20.5

xillary 1 to SN () 112.7 104.7PA () 94.9 89.6xillary 1 to facial plane (mm) 15.9 9.8ndibular 1 to facial plane (mm) 11.8 6.8solabial angle () 81.0 104.0per lip to Ricketts E-line (mm) 1.8 1.9wer lip to Ricketts E-line (mm) 5.2 0.5On the cephalometric superimposition, the maxil-y incisors were confirmed to be retracted 6.1 mm to

thema

ve

we

us

attme

mo

Betwwhmm

plathema

oc

arm

Thma

ma

an

tip

slo


Park et al 541facial plane, with lingual tipping as intended and thendibular incisors retracted 5.0 mm. The sagittal and

rtical movements of the posterior teeth in the maxillare negligible because the mini-implants had been

ed during the retraction period (Fig 7).The orthodontic mini-implant is placed on the

ached gingiva to aid soft-tissue healing after place-nt and to prevent the unnecessary coverage of thevable mucosa, unless the closed method is intended.cause the average keratinized gingival width be-een the maxillary second premolar and second molarere mini-implants are placed most often is 4.6 1.3,18,19 the height at which the mini-implants are

ced is about 5.0 mm from the gingival margin. Onbuccal side, the line of force used to retract the

xillary anterior teeth is adjusted to be parallel to theclusal plane by changing the length of the clear lever

that is bonded to the labial surface of the canine.erefore, this line5 mm high from the gingivalrginpasses below the center of resistance of the 6xillary anterior teeth. On the palatal side, the appli-

ce is fabricated to make the teeth move with lingualping, as explained previously.

Fig 7. CephalometPlacing the orthodontic mini-implants on the palatalpe between 2 adjacent roots and connecting the

levslostic chains directly to the mini-implants wouldprove both the appliance design and the patients

perimposition.

8. After space closure, brackets were bonded fortailing.elaim

ric su

Figdeel of comfort. However, the soft tissue of the palatalpe, which is thicker than that of the midpalate, can

deratimpasuc

forillacloa c

thetoomo

can

inca d


542 Park et alcrease the stability of mini-implants.20 If the successe is to be increased, it is better to use a long mini-plant to compensate for the thick soft tissue. Thistient was treated with a segmented arch technique. Inh cases, the first thing that should be monitored is archm. In this patient, the discontinuity between the max-ry canine and the second premolar occurred after spacesure because the anterior segment was not retracted onontinuous archwire. When space closure was complete,appliances were bonded to control the root axis of eachth and to seat the occlusion. This took approximately 6nths. When the pretreatment and posttreatment inter-ine and intermolar widths were compared, a slight

Fig 9. Posttreatment extraorrease in intercanine width (from 34.5 to 35.7 mm) andecrease in intermolar width (from 45.4 to 43.0 mm)

su

stere observed. The second area of consideration isting of the anterior segment. If the height of the

raction force application point differs on each side,ting cannot be avoided. To prevent this, care must been in appliance fabrication and in the insertion point ofmini-implants. Monitoring should be continued after

raction starts. The last aspect to be considered islination of the anterior teeth. Inclination can be con-lled by manipulation of the appliance, and cliniciansst monitor whether the teeth are moving in the desiredection.With segmented mechanics, as used in this pa-

nt, appliance fabrication is a critical factor in the

intraoral photographs.we

can

retcan

taktheretinctromu

dir

tie

al andccess of treatment. Instead of 0.9-mm stainlessel wire soldered to mesh, fiber-reinforced compos-

iteteethemu

su

wh

CO

mius

cloco

ad

invisca

Ortheme

retpo

RE

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.


Park et al 543can be used for splinting the 6 maxillary anteriorth by bonding to the teeth, and then a lever arm ofrequired length can be bonded.21,22 This will be

ch easier to fabricate and bond to the toothrfaces, and can be repaired simply by rebondingen the appliance is separated from the teeth.

NCLUSIONS

In a patient who complained of lip protrusion andnor crowding, the extraction space was closed bying a mesh-soldered lingual retractor. After spacesure, the minor crowding and root axes were

Fig 10. Posttreatment radiographs.rrected with bonded appliances. There are somevantages to this technique. During space closure,

17.isibility can be ensured because the splinting wirebonded to the lingual surface, and the facial profilen be improved from the beginning of treatment.thodontic mini-implants allow easy adjustments to

line of force to obtain the desired tooth move-nt, and a maximum amount of anterior toothraction is possible without anchorage loss in thesterior teeth.

FERENCES

Bell WH. Correction of maxillary excess by anterior maxillaryosteotomy. A review of three basic procedures. Oral Surg OralMed Oral Pathol 1977;43:323-32.Gantes B, Rathbun E, Anholm M. Effects on the periodontiumfollowing corticotomy-facilitated orthodontics. Case reports.J Periodontol 1990;61:234-8.Wilcko WM, Wilcko T, Bouquot JE, Ferguson DJ. Rapidorthodontics with alveolar reshaping: two case reports ofdecrowding. Int J Periodontics Restorative Dent 2001;21:9-19.Liou EJ, Huang CS. Rapid canine retraction through distractionof the periodontal ligament. Am J Orthod Dentofacial Orthop1998;114:372-82.Burstone CJ. Rationale of the segmented arch. Am J Orthod1962;48:805-22.Burstone CJ. The mechanics of the segmented arch techniques.Angle Orthod 1966;36:99-120.Burstone CJ. The segmented arch approach to space closure.Am J Orthod 1982;82:361-78.Laino A, Cacciafesta V, Martina R. Treatment of tooth impactionand transposition with a segmented-arch technique. J Clin Orthod2001;35:79-86.Cacciafesta V, Melsen B. Mesial bodily movement of maxillaryand mandibular molars with segmented mechanics. Clin OrthodRes 2001;4:182-8.Park YC, Lee SY, Kim DH, Jee SH. Intrusion of posterior teethusing mini-screw implants. Am J Orthod Dentofacial Orthop2003;123:690-4.Lee JS, Kim DH, Park YC, Kyung SH, Kim TK. The efficientuse of midpalatal miniscrew implants. Angle Orthod 2004;74:711-4.Park YC, Chu JH, Choi YJ, Choi NC. Extraction space closurewith vacuum-formed splints and miniscrew anchorage. J ClinOrthod 2005;39:76-9.Smith RJ, Burstone CJ. Mechanics of tooth movement. Am JOrthod 1984;85:294-307.Park YC, Choy K, Lee JS, Kim TK. Lever-arm mechanics inlingual orthodontics. J Clin Orthod 2000;34:601-5.Vanden Bulcke MM, Dermaut LR, Sachdeva RC, BurstoneCJ. The center of resistance of anterior teeth during intrusionusing the laser reflection technique and holographic inter-ferometry. Am J Orthod Dentofacial Orthop 1986;90:211-20.Vanden Bulcke MM, Burstone CJ, Sachdeva RC, Dermaut LR.Location of the centers of resistance for anterior teeth duringretraction using the laser reflection technique. Am J OrthodDentofacial Orthop 1987;91:375-84.

Samuels RH, Rudge SJ, Mair LH. A comparison of the rate ofspace closure using a nickel-titanium spring and an elastic

18.

19.

URNA

f backics forom MCust

52 or


544 Park et alAVAILABILITY OF JO

As a service to our subscribers, copies oOrthodontics and Dentofacial Orthopedtained and are available for purchase fPlease write to Elsevier Inc. SubscriptionOrlando, FL 32887, or call 800-654-24

availability of particular issues and prices.L BACK ISSUES

issues of the American Journal ofr the preceding 5 years are main-osby until inventory is depleted.

omer Service, 6277 Sea Harbor Dr,407-345-4000 for information onmodule: a clinical study. Am J Orthod Dentofacial Orthop1993;103:464-7.Tenenbaum H, Tenenbaum M. A clinical study of the width ofthe attached gingiva in the deciduous, transitional and permanentdentitions. J Clin Periodontol 1986;13:270-5.Kim JS, Moon IS, Chai JK, Cho KS. Clinical study on the widthof attached gingiva the subjects with healthy gingiva, or earlystage of gingivitis. J Korean Aca Periodontol 1997;27:235-48.

20. Kim HJ, Yun HS, Park HD, Kim DH, Park YC. Soft-tissue andcortical-bone thickness at orthodontic implant sites. Am J OrthodDentofacial Orthop 2006;130:177-82.

21. Freudenthaler JW, Tischler GK, Burstone CJ. Bond strength offiber-reinforced composite bars for orthodontic attachment. Am JOrthod Dentofacial Orthop 2001;120:648-53.

22. Burstone CJ, Kuhlberg AJ. Fiber-reinforced composites in orth-odontics. J Clin Orthod 2000;34:271-9.

Esthetic segmental retraction of maxillary anterior teeth with a palatal appliance and orthodontic mini-implantsAppliance fabricationCase studyRESULTS AND DISCUSSIONCONCLUSIONSREFERENCES

pi is 0889540606013230

Documents