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Long-term stability of maxillary groupdistalization with interradicular miniscrews in apatient with a Class II Division 2 malocclusion
Shingo Kuroda,a Natsuko Hichijo,b Minami Sato,b Akiko Mino,b Nagato Tamamura,c Mitsuhiro Iwata,d
and Eiji Tanakae
Tokushima, Amagasaki, and Okayama, Japan, and Jeddah, Saudi Arabia
We successfully treated a Class II Division 2 patient with maxillary group distalization using interradicular mini-screws. A woman, aged 28 years 11months, had a convex profile and an excessive overjet caused by a skeletalClass II jaw-base relationship. After leveling and alignment, titanium miniscrews were obliquely implanted be-tween the maxillary second premolar and first molar. To distalize the maxillary dentition, nickel-titanium closingcoil springs with a 2-N load were placed between the screws and the hooks on the archwire. After 28 months ofactive orthodontic treatment, a proper facial profile and an acceptable occlusion were achieved with a 4-mm dis-talization of the maxillary dentition. The resultant occlusion was stable throughout a 5-year retention period.Interradicular miniscrews were useful to distalize the maxillary dentition for correcting a Class II malocclusion.This new strategy, group distalization with miniscrews, can make the treatment simpler with greater predictabil-ity. (Am J Orthod Dentofacial Orthop 2016;149:912-22)
In the treatment of a Class II malocclusion, toothextraction or nonextraction is a subject of muchdebate.1-3 In growing patients, growth modification
is often tried to improve their anteroposterior jawdiscrepancies without extractions.2 If a nongrowing pa-tient has excessive overjet or a severe arch length discrep-ancy, orthodontists are likely to choose extractiontreatment.3 However, most patients desire nonextractiontreatment, if possible, and somedonot accept extractions.
In such patients, orthodontists must seek other treat-ment options. Molar distalization can be an alternative
to correct a Class II malocclusion. However, it is noteasy to distalize the maxillary dentition completelywith traditional orthodontic mechanics.2 Various typesof molar distalizers have been developed and clinicallyused, but they cannot prevent counteractions: eg, flar-ing of the maxillary incisors.4-7 In addition, a groupdistalization of the maxillary dentition was almostimpossible in most patients.
Recently, implant-anchored orthodontics has beenshown to be effective in treating a wide variety of mal-occlusions.8-13 In particular, miniscrews have gainedacceptance because they can provide stable anchoragefor various types of tooth movement despite theirsmall diameter and short length.12 Miniscrew anchoragecan provide maxillary molar distalization without pa-tient compliance and undesirable counteractions; there-fore, now they are well regarded as a new treatmentstrategy for Class II correction.14-17 However, theirlong-term stability is still unknown.
In this case report, we demonstrate the 5-year reten-tion of a group distalization of the maxillary dentitionwith interradicular miniscrews in an adult patient witha Class II Division 2 malocclusion.
DIAGNOSIS AND ETIOLOGY
A woman, aged 28 years 11 months, had a chiefcomplaint of esthetic problems of her maxillary inci-sors. Her facial profile was convex, and the frontal
aAssociate professor, Department of Orthodontics and Dentofacial Orthopedics,Institute of Biomedical Sciences, Graduate School, Tokushima University, To-kushima, Japan.bPostgraduate student, Department of Orthodontics and Dentofacial Orthope-dics, Graduate School of Oral Sciences, Tokushima University, Tokushima, Japan.cPrivate practice, Amagasaki, Japan.dPrivate practice, Okayama, Japan.eProfessor and chair, Department of Orthodontics and Dentofacial Orthopedics,Institute of Biomedical Sciences, Graduate School, Tokushima University, To-kushima, Japan; distinguished adjunct professor, King Abdulaziz University, Jed-dah, Saudi Arabia.All authors have completed and submitted the ICMJE Form for Disclosure ofPotential Conflicts of Interest, and none were reported.Address correspondence to: Eiji Tanaka, Department of Orthodontics and Dento-facial Orthopedics, Institute of Biomedical Sciences, Tokushima University Grad-uate School, 3-18-15 Kuramoto-Cho, Tokushima 770-8504, Japan; e-mail,[email protected], January 2015; revised and accepted, July 2015.0889-5406/$36.00Copyright � 2016 by the American Association of Orthodontists.http://dx.doi.org/10.1016/j.ajodo.2015.07.045
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CASE REPORT
view was almost symmetric (Fig 1). The molar relation-ships were Angle Class II on both sides (Fig 2). Overjetand overbite were 5.0 and 0.0 mm, respectively. Themaxillary and mandibular dental midline almost coin-cided with the facial midline. In the panoramic radio-graph, the maxillary left central and right lateralincisors and the mandibularfirst molars were nonvital(Fig 3). Periapical lesions were observed in the mandib-ularfirst molars. The maxillary third molars had alreadybeen extracted, but the mandibular third molars wereimpacted.The cephalometric analysis, when compared with the
Japanese norm, showed a skeletal Class II jaw-base rela-tionship (ANB, 9.0) (Table).18 The mandibular planewas steep (mandibular plane-SN, 44.0). The maxillaryincisors were lingually inclined (U1-SN, 90.0), but themandibular incisors showed an average inclination(L1-mandibular plane, 93.5). As the result, the interin-cisal angle was increased (134.0).
TREATMENT OBJECTIVESThe patient was diagnosed as having an Angle Class II
Division 2 malocclusion with a skeletal Class II jaw-baserelationship. An excessive overjet and a reduced overbitewere also shown. The treatment objectives were toachieve (1) an acceptable occlusion with a good func-tional Class I occlusion and (2) an attractive smile andbalanced facial profile.To achieve a functional Class I occlusion, distalization
of the maxillary dentition was necessary. Then, place-ment ofi nterradicular miniscrews was planned in theposterior maxilla. The mandibularfirst molars would beextracted, andmesialization of the second and thirdmo-lars was proposed to reduce the spaces for restorations.
TREATMENT ALTERNATIVESSeveral procedures were explored to achieve an
acceptable occlusion. Extraction of the maxillaryfirst
Fig 1. Pretreatment facial and intraoral photographs.
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Fig 2. Pretreatment dental casts.
Fig 3. Pretreatment lateral cephalogram, cephalometric tracing, and panoramic radiograph.
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premolars was considered to reduce the excessive over-jet. However, the maxillary third molars had alreadybeen extracted, and 2 maxillary incisors were nonvital.Therefore, premolar extractions should be avoided toretain as many intact teeth as possible.
As for the mandibular first molars, prosthetic restora-tions without orthodontic treatment might shorten thetotal treatment period. However, this requires pulpec-tomy of the proximal teeth when bridge restorationsare chosen. Moreover, dental implants are expensive
Table. Cephalometric summary
VariableJapanesenorm* SD Pretreatment Posttreatment Postretention
ANB (�) 2.8 2.4 9.0 8.0 8.0SNA (�) 80.8 3.6 85.0 84.0 84.0SNB (�) 77.9 4.5 76.0 76.0 76.0Mandibular plane-SN (�) 37.1 4.6 44.0 44.0 44.0U1-SN (�) 105.9 8.8 90.0 88.5 88.5L1-mandibular plane (�) 93.4 6.8 93.5 90.0 90.0Interincisal angle (�) 123.6 10.6 134.0 137.0 137.0Overjet (mm) 3.1 1.1 5.0 3.0 3.0Overbite (mm) 3.3 1.9 0.0 3.0 3.0
*Wada et al,18 1981.
Fig 4. Treatment progress: A, 3 months after the start of treatment; after leveling and alignment, mini-screwswere implanted at themesial alveolus of themaxillary first premolar, andmolar distalization wasstarted with 200-g nickel-titanium closed-coil springs; in the mandible, the second molar mesializationwas started. B, 12 months later, the mandibular second molars were completely mesialized, and up-righting of the right third molar was started. C, 18 months later, the mandibular third molars werecompletely uprighted.
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and cause considerable surgical invasion, and theirlongevity is still unclear. Therefore, molar mesializationwas planned to reduce the spaces for prosthetic restora-tions and to reconstruct the whole mandibular dentitionwith vital teeth.
TREATMENT PROGRESS
The mandibular first molars were extracted, and0.022-in slot preadjusted edgewise appliances wereplaced on both arches. After leveling and alignment
with nickel-titanium archwires, the mesialization of themandibular second molars was started with closing-loop mechanics and a stainless steel archwire (Fig 4, A).
Two months after the start of treatment, miniscrews(diameter, 1.3 mm; length, 7 mm; Absoanchor; Dentos,Daegu, South Korea) were implanted at the distal alve-olus of the maxillary second premolars (Fig 5, A andC). They were inserted obliquely in the surface of thecortical bone with the self-tapping method. After the1-month latency period, distal movement of the
Fig 5. A andC,Distal movement of themaxillarymolars: miniscrews are shown at themesial alveolus ofthe first molars before distalization, but in B and D, the miniscrews are observed beside the second pre-molar after distalization, which meant a 4-mm distalization of the maxillary dentition. A and C, 2 monthsafter the start of treatment; B and D, 24 months later; A and B, right side; C and D, left side.
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maxillary dentition was started with a 2-N load of thenickel-titanium closed-coil springs (Sentalloy; Tomy,Tokyo, Japan) (Fig 4, A).At 12 months of treatment, a molar tube was
bonded on the erupting mandibular right third molar(Fig 4, B). After leveling with the nickel-titanium wires,uprighting of the mandibular right third molar wasinitiated (Fig 4, C).After removal of the edgewise appliances, a wrap-
around type of retainer was placed on the maxillaryarch, and a lingual bonded retainer was set on themandibular anterior teeth. The total active orthodontictreatment time was 28 months. During the retentionperiod, tooth whitening was performed on both denti-tions, and themaxillary incisorswere restoredwith zirco-nia crowns.
TREATMENT RESULTSOn the posttreatment facial photographs, a balanced
facial profile was achieved (Fig 6). The occlusion wasmuch more stable, and an acceptable intercuspation ofthe teeth was achieved with Class I canine and molar re-lationships (Fig 7). The mandibular second molars werecompletely mesialized to the position of thefirst molars.In the panoramic radiograph, proper root parallelism
is shown, and the impacted mandibular third molarswere uprighted and mesialized (Fig 8). The posttreat-ment cephalometric evaluation still showed a Class IIjaw-base relationship (SNA, 84.0; ANB, 8.0 ). Themaxillary molars were bilaterally distalized for 5.0 mm,but the mandibular plane angle was stable (mandibularplane-SN, 44.0) (Table). Both the maxillary and
Fig 6. Posttreatment facial and intraoral photographs.
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Fig 7. Posttreatment dental casts.
Fig 8. Posttreatment lateral cephalogram, cephalometric tracing, and panoramic radiograph.
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mandibular incisors were lingually inclined (U1-SN,88.5; L1-mandibular plane, 90.0), but the acceptableinterincisal relationship was maintained. No symptomsof temporomandibular disorder were observedthroughout active orthodontic treatment.At the 5-year postretention checkup, the occlusion
was stable, and the good facial profile was also retained(Fig 9). The panoramic radiograph and cephalometricanalysis showed little change (Figs 10 and 11; Table).
DISCUSSIONIn this patient, distal movement of the maxillary in-
cisors was required to treat the excessive overjet. Premo-lar extractions were avoided because 2 maxillary incisorswere nonvital, and there was enough bone at the poste-rior maxilla for molar distalization.
For group distalization of the maxillary dentition, itmight be believed that temporary anchorage devicesshould be placed out of the dentitioni̶e, the screwsat midpalate or miniplates at the zygomatic pro-cess.14,15,19,20 However, miniplates requireflapsurgery at both placement and removal, and theseprocedures cause considerable pain and discomfortfor patients.21 Palatal screws need some kind of bulkyappliance to connect the screw and the archwire, andthese palatal devices are also unpleasant for patients.In contrast, interradicular screws are relativelycomfortable. Nevertheless, most orthodontists stillbelieve that they are not suitable for group distaliza-tion of the dentition because the screws would comein contact with the surrounding root during toothmovement. Actually, interradicular miniscrews maynot interfere with tooth movement when they are
Fig 9. Five-year postretention facial and intraoral photographs.
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obliquely inserted in the alveolar bone with adequatebuccolingual thickness.16
In this patient, the interradicular screws were placedat the mesial alveolus of the maxillary first premolars butare shown at the middle part of the second premolar af-ter treatment (Fig 5, B and D). This means that the rootof the maxillary second premolars could pass throughthe lingual side of the obliquely inserted miniscrews.Of course, such a tooth movement is not feasible in allpatients. Analyses of the alveolar bone thickness with ra-diographs, and 3-dimensional computed tomography ifpossible, are essential before planning the treatment.Additionally, dental cast analysis measuring the bucco-lingual thickness of the alveolar basal bone is also usefulfor prediction.
In distal movements of the maxillary molars, themaxillary sinus is a major concern because tooth move-ment through bone-deficient areas is considered chal-lenging and might reduce the alveolar bone height or
the root length.22-24 Lindskog-Stokland et al23 in adog experiment and Wehrbein et al24 in a human biopsystudy described that root resorption and loss of osseoussupporting tissue occurred in the basal cortical bone ofthe nasal sinus after translatory tooth movements.They suggested that differentiation of osteoblasts isrequired for compensatory subperiosteal bone apposi-tion. However, the molar roots seemed to move intothe maxillary sinus without any serious root resorption,even though the sinus seemed to be between the molarroots in the our patient. Several clinical reports alsodemonstrated the possibility of tooth movement intothe sinus.25,26 A recent study provided histologicevidence that the sinus wall is a dynamic structure thatresponds favorably to mechanical stress, such as toothmovement.27 Therefore, the possibility of tooth move-ment into the sinus under suitable and safe conditionsshould ultimately contribute to expanding the limits oforthodontic treatment.
Fig 10. Lateral cephalogram, cephalometric tracing, and panoramic radiograph at the 5-year postre-tention checkup.
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Maxillary group distalization improved the horizon-tal open bite and provided adequate anterior guidance.Extraction of the pathologic mandibular first molarsand succeeding molar mesialization could make themandibular dentition intact, avoiding any prosthetic res-torations. Moreover, the maxillary left central and rightlateral incisors were restored with zirconia jacket crownsafter tooth whitening. This interdisciplinary approach, acombination of orthodontic and restorative treatment,significantly improved the patient's dental estheticsand function, contributing to the increase of her qualityof life.
In this patient, the occlusion was stable, and littlerelapse occurred during the 5-year retention period,even though a large amount of molar distalizationwas achieved with miniscrew anchorage. A recent lon-gitudinal study with pendulum appliances for distali-zation showed that first molars were distalized for4 mm with 10� of tipping, but almost half of the pa-tients experienced relapse during the succeeding mul-tibracket treatment.28 In our patient, the distalizedmolars were initially tipped back but controlled wellduring the finishing and detailing phase. Control ofdistal tipping after molar distalization might be 1important key for the stability of the distalized denti-tion. In addition, the mandibular plane angle did notincrease during active orthodontic treatment and
was also stable during the retention period. With thesesimple molar distalizing mechanics with inerradicularscrews, the distalized maxillary molars can be slightlyintruded.16,17 As a result, the mandibular plane anglecan be stabilized even though the molars areextremely distalized. The strict vertical control mightalso be important to prevent relapses. However, noauthors have evaluated the long-term stability ofmolar distalization with interradicular miniscrews.Further studies are required to confirm their retentionand stability.
CONCLUSIONS
Interradicular miniscrews are useful to distalize themaxillary dentition for correcting a Class II malocclusion.With this new strategy, group distalization with mini-screws can make the treatment simpler with greater pre-dictability.
REFERENCES
1. Vaden JL, Kiser HE. Straight talk about extraction and nonextrac-tion: a differential diagnostic decision. Am J Orthod DentofacialOrthop 1996;109:445-52.
2. de Almeida-Pedrin RR, Henriques JF, de Almeida RR, deAlmeida MR, McNamara JA Jr. Effects of the pendulum appliance,cervical headgear, and 2 premolar extractions followed by fixed
Fig 11. Cephalometric tracings at pretreatment (black lines), posttreatment (red lines), and 5-yearpostretention (green lines) superimposed on A, the sella-nasion plane at sella; B, the anterior palatalcontour; and C, the mandibular plane at menton.
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appliances in patients with Class II malocclusion. Am J OrthodDentofacial Orthop 2009;136:833-42.
3. Janson G, Barros SE, de FreitasMR, Henriques JF, Pinzan A. Class IItreatment efficiency in maxillary premolar extraction and nonex-traction protocols. Am J Orthod Dentofacial Orthop 2007;132:490-8.
4. McSherry PF, Bradley H. Class II correction-reducing patientcompliance: a review of the available techniques. J Orthod 2000;27:219-25.
5. Hilgers JJ. The pendulum appliance for Class II non-compliancetherapy. J Clin Orthod 1992;26:706-14.
6. Carano A, Testa M. The distal jet for upper molar distal movement.J Clin Orthod 1996;30:374-80.
7. Jones RD, White JM. Rapid Class II molar correction with an open-coil jig. J Clin Orthod 1992;26:661-4.
8. Creekmore TD, Eklund MK. The possibility of skeletal anchorage. JClin Orthod 1983;17:266-9.
9. Roberts WE, Marshall KJ, Mozsary PG. Rigid endosseous implantutilized as anchorage to protract molars and close an atrophicextraction site. Angle Orthod 1990;60:135-52.
10. Costa A, Raffainl M, Melsen B. Miniscrews as orthodonticanchorage: a preliminary report. Int J Adult Orthodon OrthognathSurg 1998;13:201-9.
11. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H.Skeletal anchorage system for open bite correction. Am J OrthodDentofacial Orthop 1999;115:166-74.
12. Kyung HM, Park HS, Bae SM, Sung JH, Kim IB. Development of or-thodontic micro-implants for intraoral anchorage. J Clin Orthod2003;37:321-8.
13. Kuroda S, Katayama A, Takano-Yamamoto T. Severe anterioropen-bite case treated using titanium screw anchorage. Angle Or-thod 2004;74:558-67.
14. Sar C, Kaya B, Ozsoy O, €Ozcirpici AA. Comparison of two implant-supported molar distalization systems. Angle Orthod 2013;83:460-7.
15. Fudalej P, Antoszewska J. Are orthodontic distalizers reinforcedwith the temporary skeletal anchorage devices effective? Am J Or-thod Dentofacial Orthop 2011;139:722-9.
16. Yamada K, Kuroda S, Deguchi T, Takano-Yamamoto T,Yamashiro T. Distal movement of maxillary molars usingminiscrewanchorage in the buccal interradicular region. Angle Orthod 2009;79:78-84.
17. Bechtold TE, Kim JW, Choi TH, Park YC, Lee KJ. Distalizationpattern of the maxillary arch depending on the number of ortho-dontic miniscrews. Angle Orthod 2013;83:266-73.
18. Wada K, Matsushita K, Shimazaki S, Miwa Y, Hasuike Y, Susami R.An evaluation of a new case analysis of a lateral cephalometricroentgenogram. J Kanazawa Med Univ 1981;6:60-70.
19. Kinzinger GS, G€ulden N, Yildizhan F, Diedrich PR. Efficiency of askeletonized distal jet appliance supported by miniscrewanchorage for noncompliance maxillary molar distalization. AmJ Orthod Dentofacial Orthop 2009;136:578-86.
20. Sugawara J, Kanzaki R, Takahashi I, Nagasaka H, Nanda R. Distalmovement of maxillary molars in nongrowing patients with theskeletal anchorage system. Am J Orthod Dentofacial Orthop2006;129:723-33.
21. Kuroda S, Sugawara Y, Deguchi T, Kyung HM, Takano-Yamamoto T. Clinical use of miniscrew implant as orthodonticanchorage: success rate and postoperative discomfort. Am J Or-thod Dentofacial Orthop 2007;131:9-15.
22. Wehrbein H, Bauer W, Wessing G, Diedrich P. The effect of themaxillary sinus floor on orthodontic tooth movement. FortschrKieferorthop 1990;51:345-51.
23. Lindskog-Stokland B, Wennstrom JL, Nyman S, Thilander B. Or-thodontic tooth movement into edentulous areas with reducedbone height. An experimental study in the dog. Eur J Orthod1993;15:89-96.
24. Wehrbein H, Fuhrmann RA, Diedrich PR. Human histologic tissueresponse after long-term orthodontic tooth movement. Am J Or-thod Dentofacial Orthop 1995;107:360-71.
25. Oh H, Herchold K, Hannon S, Heetland K, Ashraf G, Nguyen V,et al. Orthodontic tooth movement through the maxillary sinusin an adult with multiple missing teeth. Am J Orthod DentofacialOrthop 2014;146:493-505.
26. Kuroda S, Iwata M, Tamamura N, Ganzorig K, Hichijo N, Tomita Y,et al. Interdisciplinary treatment of a nonsyndromic oligodontiapatient with implant-anchored orthodontics. Am J Orthod Dento-facial Orthop 2014;145(Suppl):S136-47.
27. Kuroda S, Wazen R, Moffatt P, Tanaka E, Nanci A. Mechanicalstress induces bone formation in the maxillary sinus in a short-term mouse model. Clin Oral Investig 2013;17:131-7.
28. Caprioglio A, Fontana M, Longoni E, Cozzani M. Long-term eval-uation of the molar movements following pendulum and fixed ap-pliances. Angle Orthod 2013;83:447-54.
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