Protraction of mandibular second and third molars into missing … · 2017-12-21 · and intrude the maxillary right and left ﬁrst molars with an elastic thread (Fig 5).7 This technique

CASE REPORT

Protraction of mandibular second and thirdmolars into missing first molar spacesfor a patient with an anterior open biteand anterior spacing

Un-Bong Baik,a Youn-Sic Chun,b Min-Ho Jung,c and Junji Sugawarad

Seoul, Korea, and Sendai, Japan

aPrivabProfeUnivecPrivatistry,dPrivaThe aucts oReprinSongjbaikuSubm0889-Copyrdoi:10

In a young woman, aged 18 years 8months, who had an anterior open bite and anterior spacing, the right and leftmandibular first molar extraction spaces were closed by protraction of the second and third molars without recip-rocal retraction of the incisors and the premolars. The amounts of protraction for the second molars were 12 mmon the right side and 11mm on the left side. Twominiscrews were inserted into themesiobuccal side of the eden-tulous spaces, and 2 more screws were inserted into the anterior sites after removing previous miniscrews. Inaddition, 4 miniscrews were inserted into the buccal and palatal sides between the first and second maxillarymolars to intrude the maxillary posterior teeth, which had extruded into the missing mandibular spaces. Carefulbiomechanical consideration was used to prevent extrusion of themolars and worsening of the anterior open bitefrom protraction of the posterior teeth. Ultimately, the anterior open bite was corrected by both intrusion of themaxillary molars and extrusion of the maxillary anterior teeth. Excellent occlusion and correction of the anterioropen bite were achieved without tipping, rotation of the posterior teeth, or other problems. The right mandibularthird molar, which had been impacted at the beginning of treatment, erupted into the second molar space andfunctioned properly. At the 1-year follow-up examination, the patient had a slight anterior open bite, but closureof the first molar extraction spaces was well maintained. (Am J Orthod Dentofacial Orthop 2012;141:783-95)

When a mandibular first molar is lost, ortho-dontic replacement with second and thirdmolars would be an excellent treatment

option if success were guaranteed. Stepovich1 presentedthe possibilities of these methods without severe compli-cations, such as root resorption and tipping of adjacentteeth. At that time, however, the space was closed mostlyby reciprocal movement of the anterior and posteriorteeth, because no temporary skeletal anchorage deviceswere available. Roberts et al2,3 used endosseous implantsplaced in the retromolar area to close missing first molar

te practice, Seoul, Korea.ssor, Division of Orthodontics, Department of Dentistry, Ewha Womansrsity, Mokdong Hospital, Seoul, Korea.te practice, clinical professor, Department of Orthodontics, School of Den-Seoul National University, Seoul, Korea.te practice, Sendai, Japan.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.t requests to: Un-Bong Baik, Smile with Orthodontic Clinic, 35-5ung-dong, Ecopia B 7F, Seoul 142-100, Korea (ROK); e-mail,[email protected], June 2010; revised and accepted, July 2010.5406/$36.00ight � 2012 by the American Association of Orthodontists..1016/j.ajodo.2010.07.031

spaces by mesial movement of the mandibular molars. Inrecent years, orthodontic miniscrews, which are moreconvenient, simple, and cheaper than endosseousimplants, have been used widely. Kyung et al4 reporteda 9-mmmesial movement of mandibular second molars,and Nagaraj et al5 reported an 8-mm movement usingminiscrews to close bilateral missing mandibular firstmolar spaces. Kravitz and Jolley6 discussed problems,such as buccal proclination, during mandibular molarprotraction with miniscrews.

Treatment is difficult when pure protraction of thesecond and third molars is required without retractionof the anterior and premolar teeth. In addition, treat-ment would be more complicated if the patient had ananterior open bite and long edentulous spaces.

Our patient was missing both mandibular first mo-lars, and the maxillary first molars had extruded intothe edentulous mandibular spaces. In addition, the pa-tient had an anterior open bite. Protraction of the man-dibular second molars was necessary, since there was noprotrusion or crowding of the anterior teeth.

After treatment, good occlusion and the correction ofthe anterior open bite were achieved. The amounts of

783

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_surname

Delta:1_surname

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_surname

Delta:1_surname

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_given name

Delta:1_surname

Delta:1_surname

mailto:[email protected]

Fig 1. Pretreatment facial and intraoral photographs.

784 Baik et al

protraction of the mandibular second and third molarswere 12 mm on the right side and 11 mm on the left side.

DIAGNOSIS AND ETIOLOGY

A young woman, aged 18 years 8 months, sought anorthodontic evaluation with chief complaints of an ante-rior open bite and spacing. She also wanted to close themissing mandibular first molar spaces by orthodontictooth movement, if possible. The right and left mandib-ular first molars had been extracted 4 months previously,because of severe caries.

The patient had a straight profile with a slightly pro-truded chin. Vertically, she had a long face with a highgonial angle. No remarkable facial asymmetry was seen(Fig 1). Intraorally, she had anterior spacing in the man-dibular arch, an anterior open bite (�1.0 mm of over-bite), and an end-to-end incisor relationship (0.0 mmof overjet). Both mandibular first molars were missing.The dental casts showed that the lengths of the

June 2012 � Vol 141 � Issue 6 American

mandibular edentulous spaces were 11.5 mm on rightside and 10.5 mm on the left side (Fig 2). The rightand left maxillary first molars had extruded into themissingmandibular first molar edentulous sites. Withoutintrusion of these maxillary molars, protraction of themandibular second molars would be difficult becauseof their potential contact against the maxillary molars.

The maxillary dental midline was coincident with thefacial midline, and the mandibular dental midline wasdeviated 1.0 mm to the left. The canines exhibiteda mild Class II occlusion, especially on the right side.To achieve a Class I occlusal relationship, the secondmo-lars would need to be protracted beyond the first molarextraction sites.

A panoramic radiograph showed long edentulousspaces and a slight mesial tilt of the left second molarin the mandible. The right third molar was impacted,but the developing status was good (Fig 3). Lateral ceph-alometric analysis (Fig 4, Table) showed a mild skeletalClass III relationship (ANB angle, 3.0�; Wits appraisal,

Journal of Orthodontics and Dentofacial Orthopedics

Fig 2. Pretreatment study models.

Fig 3. Pretreatment panoramic radiograph.

Fig 4. Pretreatment lateral cephalogram.

Baik et al 785

�4.5 mm). Vertically, the patient showed a long facialtendency (FMA, SN-MP angle, and ANS-Me/N-ANS)with an anterior open bite. Soft-tissue analysis showeda slight protrusion of the lower lip (lower lip to E-line,2.5 mm).

The functional assessment showed no remarkablediscrepancy between centric occlusion and centric rela-tion, and no apparent signs and symptoms of temporo-mandibular joint dysfunction. There were no othermedical or dental problems.

American Journal of Orthodontics and Dentofacial Orthopedics June 2012 � Vol 141 � Issue 6

Table. Summary of cephalometric analysis

Measurement Normal 1 SD Pretreatment Posttreatment 1 year after retentionMaxillomandibular relationshipsSNA (�) 83.1 2.8 80.0 80.0 80.0SNB (�) 79.5 2.7 77.0 77.5 77.0ANB (�) 3.6 1.5 3.0 2.5 3.0Wits appraisal (mm) �1.3 2.6 �4.5 �5.0 �4.5

Vertical skeletal relationshipsMandibular plane to SN (�) 36.0 3.6 42.5 42.5 43.0FMA (�) 29.0 3.6 37.0 37.0 37.5Gonial angle (�) 126.6 6.0 125.0 125.5 125.0ANS-Me/N-ANS 1.2 0.1 1.6 1.6 1.6

Dental relationshipsU1 to SN (�) 105.3 5.1 102.0 100.0 100.0U1 to FH (�) 112.3 5.1 108.0 106.0 106.0FMIA (�) 60.3 5.4 50.0 48.5 48.0IMPA (�) 90.7 5.6 92.0 90.5 90.5Interincisal angle (�) 128.0 8.0 123.0 124.5 124.0

Soft tissuesUpper lip to E-line (mm) �1.0 0.86 �1.5 �1.0 �1.0Lower lip to E-line (mm) 0.0 0.56 2.5 2.5 2.0

Fig 5. Labiolingual archwire to intrude the maxillary first molars (top row); after 3 months, sufficientintrusion was achieved (bottom row).

786 Baik et al

TREATMENT OBJECTIVES

We planned to maintain the anteroposterior positionof the maxillary incisors, since there was no significantfacial profile problem, except for the slight protrusionof the lower lip. The main treatment objectives consistedof protracting the mandibular second and third molarsto close the missing first molar spaces and to correctthe anterior open bite. Mandibular anterior spacingwould be closed by retraction of the incisors and pro-traction of the premolars, because the protraction was


needed to improve the existing Class II canine relation-ship. Vertical facial height would be maintained, becauseof the original long-face tendency.

TREATMENT ALTERNATIVES

Spaces caused by missing mandibular first molars canbe corrected by prosthetic bridges, dental implants, au-totransplantation of third molars, or mesial orthodonticmovement of second and third molars. Prostheticbridges offer the advantage of short treatment time


Fig 6. Miniscrews (6 mm long, 1.5 mm in diameter) were placed into the mesiobuccal sides of the firstmolar extraction spaces.

Fig 7. During protraction, the anterior open bite became more severe because of the extrusion of theright and left second molars.

Baik et al 787

but must be accompanied by significant tooth prepara-tion. Dental implants permit conservation of toothstructure but require surgery. Autotransplantation alsorequires surgery, and successful transplantation cannotbe guaranteed. To improve facial esthetics and skeletaldiscrepancies such as a protruded chin, orthognathicsurgery might be another option.

Our patient finally chose orthodontic replacement,because she wanted to correct additional tooth-position problems, including anterior spacing and ananterior open bite. She also hoped to avoid surgicaltrauma. The patient rejected orthognathic surgery,because she did not want dramatic changes in facialappearance and extensive surgical trauma.

TREATMENT PROGRESS

First, a labiolingual wire (0.9 mm stainless steel) wasattached to several other teeth to reinforce anchorage

American Journal of Orthodontics and Dentofacial Orthoped

and intrude the maxillary right and left first molarswith an elastic thread (Fig 5).7 This technique intrudedthe maxillary first molars that were initially extrudedinto the missing mandibular first molar spaces. Pread-justed edgewise appliances with 0.018-in slots werebonded to the mandibular teeth after the maxillary firstmolar was sufficiently intruded. After leveling and align-ment, orthodontic miniscrews (6.0 mm long, 1.5 mmdiameter; Orlus, Seoul, Korea) were placed into the me-siobuccal sides of both missing mandibular first molarspaces under local anesthesia (Fig 6). Two weeks afterplacement, an elastic module (force, 150 g) was con-nected from the miniscrews to the hook of the bracketattached to both the right and left second molars. A0.016 3 0.022-in heat-treated stainless steel wire wasused as a working wire, and the right and left mandibularsecond molars were protracted with sliding mechanics.

During protraction, the anterior open bite worsenedslightly because of posterior occlusal interference by

ics June 2012 � Vol 141 � Issue 6

Fig 8. The initial 2 miniscrews (mandibular) were removed, and 2 additional screws were placed be-tween the mandibular first premolar and canine on the buccal side. Two other miniscrews were placedin the buccal side between the maxillary first and second molars to intrude them. During this time, bothmaxillary third molars were extracted simultaneously, and a transpalatal arch was attached to thelingual side of the maxillary molars to prevent buccal flaring.

Fig 9. Miniscrews were inserted into the palatal side to prevent buccal flaring of the maxillary molars.Complete closure of the missing first molar spaces can be seen, and there was no rotation of themolars.

788 Baik et al

the extruded mandibular second molars (Fig 7). Wealso observed mesial rotation of the mandibular mo-lars, especially on the right side. To solve these prob-lems, we changed the mechanics: (1) bands wereremoved from the second molars, and bracketswere directly bonded onto the more mesial side ofthe second molars, and new brackets were bonded


to both right and left third molars; (2) long buccalhooks were attached to the second molar bracketsto protract the molars through their centers of resis-tance; and (3) the initial 2 miniscrews were removedbefore impeding the mesial movement of the secondmolars, even though the spaces were not completelyclosed.


Fig 10. Posttreatment facial and intraoral photographs.

Baik et al 789

Two additional miniscrews (6.0 mm long, 1.5 mm indiameter; Biomaterials Korea, Seoul, Korea) were placedon the buccal side between the mandibular first premo-lars and canines to help complete the protraction of thesecond molars. Two miniscrews (8.0 mm long, 1.5 mm indiameter; Biomaterials Korea) were placed into the buc-cal side between the maxillary first and second molars tocorrect the anterior open bite by intruding the maxillarymolars. During this time, both the right and left maxil-lary third molars were extracted, and a transpalatalarch was attached to the palatal side of the maxillarymolars to prevent buccal proclination (Fig 8). Two weeksafter miniscrew insertion, protraction of the mandibularmolars and intrusion of the maxillary molars were begunby using an elastic module and thread.

The anterior open bite improved as treatment pro-gressed. Despite the use of the transpalatal arch, someproclination of the maxillary molars occurred, so 2 addi-tional miniscrews (10.0 mm long, 1.5 mm in diameter;Biomaterials Korea) were inserted into the palatal side


between the maxillary first and second molars to provideadditional intrusive force from that side (Fig 9). A total of8 miniscrews were used. Greater intrusion of the maxil-lary molars was achieved by using both the palatal andbuccal sides. Consequently, the anterior open biteimproved.

After finishing and detailing, the brackets and theminiscrews were removed. Active treatment time was50 months. A 0.0175-in twisted-wire fixed retainerwas attached onto the lingual surfaces of the anteriorteeth in both arches immediately after debonding. Haw-ley retainers were also used in both arches.

TREATMENT RESULTS

All of the original treatment objectives were achieved.The maxillary and mandibular arches were well alignedand coordinated without midline deviations. Normaloverbite and overjet were achieved (Fig 10). The finalmodels showed favorable Class I molar and canine


Fig 11. Posttreatment dental casts. Good functional occlusion can be seen from the lingual aspect.

Fig 12. Posttreatment panoramic radiograph.

Fig 13. Posttreatment lateral cephalogram.

790 Baik et al

relationships and excellent intercuspation (Fig 11). Goodfunctional occlusion was seen from the lingual aspect ofthe posttreatment dental cast. The edentulous spaces inthe mandibular arch were completely closed by protrac-tion of the second and third molars.

The premolars and the canines alsomoved slightlyme-sially; this helped to improve the Class II canine relation-ship seen at the beginning of treatment. As a result, theamount of mesial movement of the mandibular second

June 2012 � Vol 141 � Issue 6 American Journal of Orthodontics and Dentofacial Orthopedics

Fig 14. Cephalometric superimpositions between the pretreatment and posttreatment stages: overall,maxilla, and mandible.

Baik et al 791

and third molars became greater than the span of theoriginal missing spaces (12 and 11 mm on the right andleft sides, respectively, compared with the original 11.5and 10.5 mm). The mandibular anterior spacing was cor-rected both by retraction of the mandibular incisors andprotraction of the mandibular premolars. The mesiallytipped mandibular second molars were uprighted. Theposttreatment panoramic radiograph showed good rootparallelism (Fig 12). There was no remarkable root resorp-tion. All teeth showed good alveolar bone height. Theprobing depths were 2.0 to 2.5 mm around the mandib-ular second and thirdmolars. Posttreatment cephalogramand superimposed tracing shows themesial movement ofthe second and third molar (Figs 13 and 14).

The maxillary incisors were retracted and extruded,which contributed to correcting the anterior open bite,but this increased the amount of visible gingivae whensmiling. Gingival recontouring of the maxillary incisorarea was recommended at the time of debonding. How-ever, the patient rejected this option. The intrusion ofthe maxillary molars was another constituent for the cor-rection of the open bite. There was no significant changein the facial profile with no increase in facial height. Thelower lip was slightly retracted; this helped to improvethe Class III profile. The changes in the upper lip andchin were minimal during treatment.


Wire fixed retainers were attached to the lingual as-pect of each tooth from the right to the left canines inboth arches. The patient wore a Hawley retainer for 15hours per day for the first 2 months, followed by another10 months of nighttime wear. After 1 year of retention,there was a slight relapse of the anterior open bite, butthe amount was minimal. The mandibular edentulousspaces did not reopen. Comparison of the posttreatmentand 1-year retention facial photos and cephalogramsshowed only minor dental and skeletal changes(Figs 15-18; Table).

DISCUSSION

Recently, there have been more reports about ortho-dontic protraction of the second and third molars intomissing first molar spaces.4-6 Compared with othercases previously reported, our patient is different inseveral ways. First, the edentulous spans were longer(11.5 and 10.5 mm). Second, the edentulous spaceswere closed entirely by protraction of the second andthird molars. In addition, the canines and thepremolars were also protracted to correct the Class IIcanine relationships. As a result, the final amounts ofmesial movement of the second and third molars were12.0 and 11.0 mm on right and left sides, respectively.


Fig 15. Postretention (1 year) facial photographs and intraoral photographs.

Fig 16. Postretention (1 year) panoramic radiograph.

792 Baik et al

The more the molars move, the greater the risk ofcomplications.

During the movement of a tooth over a long distance,tipping is a big concern. To prevent mesial tipping,a heat-treated 0.016 3 0.022-in stainless steel wirewas inserted and changed at every visit. Long buccalhooks attached to the second molar brackets were alsoused to protract the teeth through their centers of resis-tance. Other special devices, such as a molar uprightingspring, were not used. Some tipping of the left mandib-ular second molar occurred in the later stages of protrac-tion; this was easily solved by rebonding the bracketswith angulation control. The final and 1-year retentionpanoramic radiographs showed good root parallelism(Figs 12 and 16). Stepovich1 also demonstrated that pos-terior mandibular edentulous spaces could be closedwithout tipping.

When protracting molars, mesial rotation of the pro-tracted teeth might occur, creating a posterior cross-bite.6 Kyung et al4 connected the right and left


mandibular second molars with a rigid lingual archand protracted the molars from a lingually placed mini-screw to prevent mesial rotation during protraction.However, the lingual arch might not only cause discom-fort to the patient, but also interfere with any furthermovement of the molars. In addition, the lingual arch


Fig 17. Postretention (1 year) lateral cephalogram.

Baik et al 793

should be remade when it touches the lingual side of theanterior teeth. Lingual placement of a miniscrew is dif-ficult, because of poor visibility and accessibility. Na-garaj et al5 prevented rotation of the molars with anelastic chain from the lingual side of the molars to a but-ton on the canine. Kravits and Jolley6 recommended theuse of a sliding band with a lingual arch. In our patient,this problem was minimized by placing an antirotationbend in the posterior portion of the archwire. Despiteour efforts, a slight mesial rotation occurred on the rightsecond molar during protraction (Fig 7). Therefore, weremoved the bands and bonded the brackets towardthe mesial sides of the teeth. At debonding, there wereno rotations or crossbites of the second and third molars(Figs 10 and 11).

The third different feature was that this patient hadan anterior open bite and a long face before treatment.Jung and Kim8 demonstrated some different biome-chanics in the skeletal anchorage system. The entirearch rotates around the center of rotation of the denti-tion in the miniscrew retraction system. Therefore,when posterior teeth are protracted, the molars wouldbe extruded, and an anterior open bite would worsen.To solve these problems, the following methods wereused. First, a long hook was attached to the secondmolar brackets to put the protracting force near thecenter of rotation. Second, the replacement miniscrewswere inserted into more anterior and deeper sites at thelater stage of the protraction (Fig 8), when the secondmolars were able to meet the initial miniscrews beforecomplete closure of the edentulous space. Deeper posi-tioning of the miniscrews helped to prevent extrusion


and tipping of the second molars during protraction(Fig 19). Third, the maxillary molar intrusion wasachieved by miniscrews (Fig 9). Usually, intrusion ofthe maxillary molars causes extrusion of the mandibu-lar molars and vice versa. Sugawara et al9 reportedmaxillary molar extrusion during mandibular molar in-trusion. This phenomenon also occurred in our patient.The mandibular molar extrusion shown in Figure 14was caused by both protraction and counteraction dur-ing the maxillary molar intrusion. The result wouldhave been better if there had been a treatment to in-hibit the extrusion of the mandibular molars such asminiscrew insertion.

Another important concern is the size of the edentu-lous ridge. The edentulous alveolar ridge might undergoresorption with time after extraction of the teeth.10 Thisproblem could complicate tooth movement. It couldtake more time for orthodontic movement, and the nar-row ridge could cause root dehiscence, resorption, orother periodontal problems. The best timing of extrac-tion is just before mesial traction. Leveling and align-ment of the teeth should be finished before traction insliding mechanics. In our patient, the mandibular rightand left first molars were extracted at another clinic 4months before our orthodontic treatment. Hence, theleveling and alignment could not be achieved before ex-traction. Yet, the relatively short latent period betweenextraction and protraction might have allowed forgood treatment results without the side effects men-tioned earlier.

In the beginning of the treatment, the mandibularright third molar had a developing root and was com-pletely covered with soft tissue. If the space for mesialmovement of the third molar were created orthodonti-cally, then the development and emergence of the toothmight be promoted.11,12 In our patient, only leveling andalignment were performed on the anterior segment ofthe mandibular dentition during the initial stages. Atthat time, there was little change in the third molar(Fig 6). After 6 months of protraction of the second mo-lar, the crown of the third molar emerged into the oralcavity (Fig 7). In the final stage of treatment, the thirdmolar was fully erupted and resembled a second molar(Figs 10 and 11). The complete exposure of the thirdmolar might decrease the possibility of infection fromplaque accumulation, the biggest problem of impactedthird molars.

The total treatment time was long (50 months). Clo-sure of the long edentulous span could have caused thelong treatment time, but trial errors were also part of thereason. In the later stages of treatment, tipping and me-sial rotation of the second molars required rebonding ofthe brackets. If the brackets had been well positioned at


Fig 18. Cephalometric superimpositions between the posttreatment and retention (1 year) stages:overall, maxilla, and mandible.

Fig 19. Different biomechanics in treatment with mini-screw anchorage:A, protraction of the posterior teeth pro-duced arch rotation around the center of rotation of theentire arch; this movement caused B, extrusion of theposterior tooth and C, intrusion of the anterior teeth.

794 Baik et al

first, considering these factors, the length of the treat-ment would have been shorter.

The patient had a slight relapse of the anterior openbite 1 year after appliance removal (Figs 17 and 18). Thisrelapse was due to a slight extrusion of the maxillarymolar during the retention phase; this was verified bysuperimposition of the posttreatment and retentiontracings (Fig 18). Sugawara et al9 previously reporteda relapse rate of 27.2% to 30.3% at 1 year after debond-ing. Relapse rates after molar intrusion are more thanthat of other tooth movements such as mesiodistalmovement or rotation for several reasons: (1) other typesof tooth movement are characterized by the formationof new bone, which inhibits relapse after tooth move-ment, but new bone cannot be formed after molar intru-sion; and (2) apical periodontal tissues reorganize moreslowly than tissues in other sites.13-15 To prevent relapseafter intrusion, Ohtani15 recommended long mechanicalretention periods of more than 16 weeks. In our patient,if traction treatment for maxillary molar intrusion hadbeen applied for a longer time, relapse of the intrudingmolar might have been reduced.

Relapse can also occur after orthognathic surgicaltreatment of an anterior open bite. Bailey et al16 andProffit et al17 reported various relapses after superior re-positioning of the maxilla by LeFort I osteotomy thatwere observed during long-term follow-ups. It is


difficult to predict the maintenance of vertical closureover the long term, because there are many contributingfactors and numerous types of relapses.

As mentioned previously, there are several options fortreating missing mandibular first molars. Autotransplan-tation is a good option, when it is important to conservethe teeth and their innate periodontal structure, and isfavorable because it does not require the use of artificialmaterials. However, the transplantation procedure canresult in surgical trauma, root resorption, ankylosis,


Baik et al 795

and infection, and the success rate of the procedurevaries.18-20 Of the other feasible methods, orthodonticreplacement of missing first molars with posteriorteeth does not produce surgical trauma except duringminiscrew insertion. Furthermore, if a patient alsodesires orthodontic treatment for other problems, theadditional treatment time required is minimal, and theextra financial burden associated with installation ofa bridge or an implant becomes unnecessary. In thissense, protraction of posterior teeth into edentulousspaces might be called “orthodontic transplantation.”This type of treatment could become more popularwith the development of temporary anchorage devices.The analysis of this case might broaden the scope ofpossibilities for this type of treatment.

CONCLUSIONS

Bilateral orthodontic traction of the mandibular sec-ond and third molars into the mandibular first molaredentulous spaces was possible without retracting theanterior teeth in a complicated case with an anterioropen bite and large edentulous spans.

REFERENCES

1. Stepovich MI. A clinical study on closing edentulous spaces in themandible. Angle Orthod 1979;49:227-33.

2. Roberts WE, Marshall KJ, Mozsary PG. Rigid endosseous implantutilized as anchorage to protract molars and close an atrophic ex-traction site. Angle Orthod 1990;60:135-52.

3. Roberts WE, Nelson CL, Goodacre CJ. Rigid implant anchorage toclose a mandibular first molar extraction site. J Clin Orthod 1994;28:693-704.

4. Kyung SH, Choi JH, Park YC. Miniscrew anchorage to protractlower second molars into first molar extraction sites. J Clin Orthod2003;37:575-9.

5. Nagaraj K, Upadhyay M, Yadav S. Titanum screw anchorage forprotraction of mandibular second molars into first molar ex-traction sites. Am J Orthod Dentofacial Orthop 2008;134:583-91.


6. Kravitz ND, Jolley T. Mandibular molar protraction with temporaryanchorage devices. J Clin Orthod 2008;42:351-5.

7. Melsen B, Fiorelli G. Upper molar intrusion. J Clin Orthod 1996;30:91-6.

8. Jung MH, Kim TW. Biomechanical considerations in treatmentwith miniscrew anchorage. Part 1. The sagittal plane. J Clin Orthod2008;42:79-83.

9. Sugawara J, Baik UB, Umemori M, Takahashi I, Nagasaka H,Kawamura H, et al. Treatment and posttreatment dentoalveolarchanges following intrusion of mandibular molars with applicationof a skeletal anchorage system (SAS) for open bite correction. IntJ Adult Orthod Orthognath Surg 2002;17:243-53.

10. Ostler MS, Kokich VG. Alveolar ridge changes in patients congen-itally missing mandibular second premolars. J Prosthet Dent 1994;71:144-9.

11. Zimmer B. Wisdom tooth eruption secondary to localized lowermolar mesialization in patients with aplastic lower second premo-lars. J Orofac Orthop 2006;67:37-47.

12. Yavuz I, Baydas B, Ikbal A, Dagsuyu IM, Ceylan I. Effect of earlyloss of permanent first molars on the development of third molars.Am J Orthod Dentofacial Orthop 2006;130:634-8.

13. Takahashi H. Stability of orthodontically rotated teeth in dogs: theeffect of mechanical retention and gingival fiber transection. JpnJ Orthod Soc 1976;35:1-18.

14. Kawarada T. Experimental study on the effect of the mechanicalretention of the tooth in dogs. Jpn J Orthod Soc 1978;37:8-36.

15. Ohtani N. A study of the relapse movement of the intruded teethand the effect of mechanical retention and gingival transection.Jpn J Orthod Soc 1980;39:390-406.

16. Bailey LJ, Philips C, Proffit WR, Turvey TA. Stability following su-perior repositioning of the maxilla by Le Fort I osteotomy:five-year follow up. Int J Adult Orthod Orthognath Surg 1994;9:163-73.

17. Proffit WR, Bailey LJ, Philips C, Turvey TA. Long-term stability ofsurgical open-bite correction by Le Fort I osteotomy. Angle Orthod2000;70:112-7.

18. Herrera H, Herrera H, Leonardo MR, de Paula e Silva FW, daSilva LA. Treatment of external inflammatory root resorption afterautogenous tooth transplantation: case report. Oral Surg Oral MedOral Pathol Oral Radiol Endod 2006;102:e51-4.

19. Reich PP. Autogenous transplantation of maxillary and mandibu-lar molars. J Oral Maxillofac Surg 2008;66:2314-7.

20. Mejare B, Wannfors K, Jansson L. A prospective study on trans-plantation of third molars with complete root formation. OralSurg Oral Med Oral Pathol Oral Radiol Endod 2004;97:231-8.


Protraction of mandibular second and third molars into missing … · 2017-12-21 · and intrude the maxillary right and left ﬁrst molars with an elastic thread (Fig 5).7 This technique

Documents