treatment outcome analysis of speedy surgical

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Treatment outcome analysis of speedy surgicalorthodontics for adults with maxillary protrusion

HyeRan Choo,a Hyun-A Heo,b Hyun-Joong Yoon,c Kyu-Rhim Chung,d and Seong-Hun Kime

Philadelphia, Pa, and Suwon and Seoul, Korea

aDirecclinicaPhiladbClinitistry,cAssoDentidProfeMediceAssoHee UThe aucts oThis sHeo aReprinDenti130-7Subm0889-Copyrdoi:10

Introduction: The purposes of this study were to quantify the treatment outcomes of speedy surgical orthodontictreatment for adults with maxillary protrusion and to identify the key factors influencing the efficacy of speedysurgical orthodontic biomechanics. Methods: Twenty-four adults with maxillary or bimaxillary protrusion weretreated with speedy surgical orthodontics, including maxillary perisegmental corticotomy followed by the ortho-pedic en-masse retraction against C-palatal miniplate anchorage. The average total treatment time was20 months (range, 11-42 months). Lateral cephalograms were taken at pretreatment, just after theperisegmental corticotomy, and at posttreatment to evaluate the skeletal and soft-tissue changes. ThePearson correlation analysis was used to identify the relationships between hard-tissue, soft-tissue, andperisegmental corticotomy variables. Results: The maxillary central incisors were retracted by 9.19 6 0.31mm and retroclined by 19.73� 6 1.17�. The change of the maxillary alveolar ridge angle was 13.97� 6 1.04�.The extrusion tendency of the retractedmaxillary incisors wasminimal, measured as 1.176 0.36mm. The widthof the buccal corticotomy showed statistically significant correlations with the angular change of the maxillarycentral incisors and themaxillary alveolar ridge angle. The retrusion of themaxillary central incisors and themax-illary alveolar ridge angle were the 2 hard-tissue variables that most closely correlated with retrusion of the upperlip.Conclusions:Speedy surgical orthodontic treatment can be an effectivemodality for adults with severemax-illary protrusion. (Am J Orthod Dentofacial Orthop 2011;140:e251-e262)

Two types of orthodontic treatment are commonlyconsidered for adults with maxillary protrusion:first premolar extractions followed by conven-

tional orthodontic therapy with tooth-borne maximumanchorage, and orthodontic therapy in conjunctionwith orthognathic surgery. In both scenarios, relativelylong treatment times are often unavoidable becausethe decreased cancellous bone volume and blood supply

tor of Craniofacial Orthodontics, The Children’s Hospital of Philadelphia;l associate, University of Pennsylvania Department of Orthodontics,elphia.cal fellow, Division of Oral and Maxillofacial Surgery, Department of Den-Catholic University of Korea, Seoul, Korea.ciate professor, Division of Oral and Maxillofacial Surgery, Department ofstry, Catholic University of Korea, Seoul, Korea.ssor and chairman, Department of Orthodontics, Ajou University School ofine, Suwon, Korea.ciate professor, Department of Orthodontics, College of Dentistry, Kyungniversity, Seoul, Korea.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.tudy was in partial fulfillment of the requirements of a thesis by Hyun-At the Catholic University of Korea.t requests to: Seong-Hun Kim, Department of Orthodontics, College ofstry, Kyung Hee University, #1 Hoegi-dong, Dongdaemun-gu, Seoul01, Republic of Korea; e-mail, [email protected], November 2009; revised and accepted, June 2011.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2011.06.029

in adults typically result in slower tooth movement.1,2

Orthodontic treatment for adults can be complicated ifthe dentition is compromised with periodontitis ormultiple restorations, or if the patient refuses to wearconventional labial orthodontic appliances for a longperiod of time.3 Therefore, the anterior segmental os-teotomy technique has become popular because it com-pensates for the limitations of conventional orthodonticbiomechanics and decreases the total treatment time inadults who need orthodontic therapy.3-7

Since the inception of the original anterior segmentalosteotomy technique in 1921,4 Wassmund,5 Cuper,6 andWunderer7 have reported various modifications.1-3

However, anterior segmental osteotomy infrequentlyhas serious risks and challenges, such as anterioralveolar necrosis, tooth devitalization, and the need forgeneral anesthesia.3,8,9 As an alternative, in 1959,K€ole10 introduced various clinical corticotomy applica-tions where the osteotomy is limited to the corticalbone level, retaining the continuity of medullary boneand minimizing the tissue damage on teeth and perio-dontium during orthodontic tooth movement. A corti-cotomy has been shown to reduce complications andmorbidity rates when compared with orthognathic sur-gery or anterior segmental osteotomy because of its op-erational simplicity.11,12 Therefore, the corticotomy

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e252 Choo et al

became popular as an aid that could overcome thebiologic limits of conventional orthodontic therapywithout involving full osteotomies. In addition, Suya11

redefined in 1991 the concept of “rapid tooth move-ment” by demonstrating the effectiveness of thetooth-embedded bony block movement after cortico-tomy. He named this concept “corticotomy-facilitatedorthodontics.”

Expanding on the concept of Suya11 to shorten con-ventional orthodontic treatment, Lee et al,13 Chunget al,14-16 Chung,17 and Kanno et al18 introduced thenovel concept of “speedy surgical orthodontics,” whichinvolved a perisegmental corticotomy, a C-palatalminiplate, and a C-palatal retractor as key componentsin treating maxillary protrusion for adults. Althoughboth speedy surgical orthodontics and corticotomy-facilitated orthodontics use a perisegmental cortico-tomy, in the former technique, the corticotomizedbone block includes 6 maxillary anterior teeth insteadof a single tooth. More importantly, speedy surgical or-thodontics can induce a bone-bending effect by apply-ing the heavy orthopedic force against a palataltemporary skeletal anchorage device (Fig 1).15,16,19,20

Recently, temporary skeletal anchorage devices such asorthodontic miniscrews and miniplates have replacedextraoral anchorage devices that rely significantly onpatient compliance.21-23 Advances in temporaryskeletal anchorage device designs and applicationshave enabled orthodontists to use absolute anchorageand heavy forces without biomechanical side effectsduring orthodontic therapy.

In speedy surgical orthodontics, the bending of the re-tracted maxillary segment is often achieved within 3 to 6months after the perisegmental corticotomy. Therefore,the orthodontic tooth movements immediately after theorthopedic retraction often occur within the time frameinfluenced by the regional acceleratory phenomenon ofFrost.24 This results in relatively faster tooth movementduring the last stage of speedy surgical orthodontictherapy. Comparedwith the accelerated osteogenic ortho-dontics ofWilcko et al,25 which rely primarily on Frost’s re-gional acceleratory phenomenon to facilitate individualtooth movements during the total orthodontic therapy,the speedy surgical orthodontic technique of Chung14-17

targets a dramatic change of tooth position bya perisegmental corticotomy and orthopedic bonebending followed by facilitated individual toothmovement. Although many studies have reportedcephalometric evaluations of the various derivatives ofsurgically assisted orthodontic therapies, such asaccelerated osteogenic orthodontics, corticotomy-facilitated orthodontics, anterior segmental osteotomy,and orthognathic surgery, few investigative efforts have

December 2011 � Vol 140 � Issue 6 American

qualitatively and quantitatively described the outcomeof speedy surgical orthodontic treatment. The purposesof this study were, therefore, to assess the clinical effectsof speedy surgical orthodontic treatment and to identifythe elements for the successful application of speedy sur-gical orthodontic biomechanics in the treatment of adultswith maxillary or bimaxillary protrusion.

MATERIAL AND METHODS

The study subjects included 24 Asian women (aver-age age, 27.3 years; range, 19-41 years) with maxillaryor bimaxillary protrusion. All patients were evaluatedand confirmed by their primary dentists to have beenmaintaining excellent dental and periodontal health inthe last 6 months. This study was approved by the insti-tutional review board of Uijeongbu St. Mary's Hospitalof the Catholic University of Korea. The inclusion criteriafor this study were (1) nongrowing women, (2) no signsor symptoms of temporomandibular joint disorder, (3)no unrestorable dental caries or congenitally missingteeth, (4) no craniomaxillofacial deformities affectingthe normal palatal anatomy, and (5) no history of sur-gery or treatment that could have affected facial soft-tissue changes. Of the 24 patients included in this study,19 were treated with a maxillary perisegmental cortico-tomy followed by an orthopedic en-masse retractioncombined with a mandibular anterior segmental osteot-omy with rigid fixation surgical plates. Another 4 pa-tients were treated with a maxillary perisegmentalcorticotomy followed by an orthopedic en-masse retrac-tion and a mandibular corticotomy only. Only 1 patientwas treated with a maxillary perisegmental corticotomyfollowed by an orthopedic en-masse retraction with nomandibular surgery.

Perisegmental corticotomy removes both the buccaland the palatal cortical bone in a continuous linearform around the teeth to be retracted. The perisegmentalcorticotomy in this study was performed under local an-esthesia in 2 stages on an outpatient basis. The first cor-ticotomy was made on the palatal side. After reflectinga full-thickness palatal periosteal flap, the corticalbone was cut horizontally 5 mm above the apices fromthe maxillary right first premolar to the left first premo-lar, by using a round bur 4 mm in diameter. The secondcorticotomy (buccal corticotomy) was performed ap-proximately 2 weeks after the palatal corticotomy. Afterthe labial full-thickness mucoperiosteal flap was ele-vated, a horizontal corticotomy was made from 1 max-illary first premolar to the other, parallel to the nasalfloor and approximately 5 mm above the root apicesof the 6 maxillary anterior teeth. The 2 vertical buccalcorticotomies were then made on the root of the

Journal of Orthodontics and Dentofacial Orthopedics

Fig 1. A, Three-dimensional cone-beam computed tomography image of corticotomized anterior max-illa and C-palatal miniplate (arrows indicate the corticotomized area); B, schematic illustrations of peri-segmental corticotomy and alveolar bone bending.

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maxillary first premolar until they met the horizontalcorticotomy. Both maxillary premolars were then ex-tracted. The depth of the osteotomy was limited to thecortical bone. The final result of this surgical procedurewas a bone block formed by 2 vertical and 1 horizontalcorticotomies while maintaining the continuity of med-ullary bone (Fig 1, A).

After the perisegmental corticotomy, a cross-shapedorthodontic C-palatal miniplate (KLSMartin, Tuttlingen,Germany; Jin Biomed Co., Bucheon, Korea) was placedat the junction of the midpalatal suture and animaginary line connecting the distal points of the rightand left maxillary first molars.15,26 This miniplateestablished the framework for absolute anchorageagainst which the orthopedic retraction force wasapplied. A custom-made C-palatal retractor was thenbonded to the palatal surface of the maxillary 6 anteriorteeth to consolidate them as a single unit. Nickel-titanium closed-coil springs were then used to connectthe C-palatal miniplate to the C-palatal retractor forthe en-masse orthopedic retraction of the corticotom-ized maxillary segment (Fig 2).15,27-29

The force applied on each side of the palatal retractorwas 600 g (1200 g total) on average. In addition to thepalatal retractor, a labial spring retractor with C-tubeplates (Jin Biomed Co.) was sometimes added for bettertorque control of the retracted segment when the pa-tient’s interincisal angle before the en-masse retractionwas within normal limits (Fig 3). The torque control of

American Journal of Orthodontics and Dentofacial Orthoped

the retracted teeth was also managed by titrating thelength of the retractor arms so that the line of retractionforce could be as close as possible to the center of resis-tance of the retracted segment.

On average, it took approximately 3 to 6 months toclose two thirds of the premolar extraction spaces by or-thopedic retraction (Fig 4). From this point, the retrac-tion pads of the maxillary canines were disconnectedfrom the retractor to subject the canines to the ortho-dontic force to establish a solid Class I relationship. Atthe same time, conventional orthodontic brackets andbands were placed on all teeth, and an initial levelingarchwire was engaged. This final stage of speedy surgicalorthodontic treatment lasted until the total orthodontictreatment was completed with ideal Class I molar and ca-nine relationships.

A series of lateral cephalograms was taken at 3 timepoints: pretreatment, postbuccal perisegmental cortico-tomy, and posttreatment. All subjects were positioned inthe cephalostat with the midsagittal plane at a right an-gle to the x-ray path and the Frankfort horizontal plane(FH) parallel to the floor. The patients were instructedto occlude in maximum intercuspation while completelyrelaxing their lips. The cephalometric landmarks, refer-ence planes, andmeasurements used in this study are de-scribed in Figures 5 through 8. All linear and angularmeasurements were taken in the 2-dimensional metricsystem made by 2 primary reference planes: FH planeand Nperp plane (a plane passing through nasion and

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Fig 2. A, Schematic illustrations of C-palatal miniplate; B, anterior segment retraction using C-palatalretractor and C-plate combined mechanics; C, after retraction.

Fig 3. Specially designed labial appliances for anterior torque control during retraction:A andB, springlabial retractor; C and D, high anterior hook appliance.

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perpendicular to the FH plane) as the vertical referenceplane. The measurements were also divided into 3 cate-gories: hard tissue, soft tissue, and corticotomy. Each pa-tient served as her own control, so that the observedchanges at the different time points were calculated bysubtracting the pretreatment value from the posttreat-ment value. A positive value indicated forward or


downward movement, and a negative value indicatedbackward or upward movement.

Statistical analysis

Statistical data were generated and interpreted by us-ing SPSS software for Windows (version 12.0; SPSS, Chi-cago, Ill). The mean and standard deviation of each


Fig 4. Intraoral photographs and lateral cephalograms of anterior segment retraction using C-palatalretractor after perisegmental corticotomy in a 25-year-old woman: A-C, 1 week after retraction;D-F, 3 months after retraction.

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variable at each time point were calculated as well as thevalue change between pretreatment and posttreatment.A paired t test was used to evaluate the treatment out-comes by comparing pretreatment and posttreatment,and the Pearson correlation analysis was used to identifyrelationships between the hard-tissue and soft-tissuechanges, and the corticotomy variables.

All lateral cephalograms were traced and measuredby 1 investigator (H.H.A.). To quantify intrarater reliabil-ity, 8 of the 24 lateral cephalograms were randomlyselected 2 weeks after the first examination and mea-sured by the same investigator. There were high correla-tion coefficients of 0.84 to 0.97 (P\0.01) when testedwith the Pearson correlation analysis.

RESULTS

The average total treatment time was 20 months(range, 11-42 months). On average, it took 3 to 6months to complete the orthopedic retraction.

At posttreatment, all changes of hard-tissue variableswere statistically significant, although the linear and an-gular changes of Point A did not show clinically signifi-cant differences (Table I). More specifically, the positionof the maxillary central incisor moved significantly back-ward by�9.196 0.31 mm with a downward movementof 1.176 0.36 mm (P\0.01). The decreases in the SNA


and maxillary alveolar ridge angles were also statisticallysignificant, measured at �1.00� 6 0.13� and �13.97�

6 1.04� (P\0.001), respectively. In parallel, the angleFH-U1 decreased between pretreatment and posttreat-ment by �19.73� 6 1.17�. The movement of Point Awas statistically significant in the backward (�1.12 60.13 mm) and downward (0.43 6 0.11 mm) directions.

Soft tissue landmarks were also changed at posttreat-ment. Labrale superius moved significantly backward(�4.60 6 0.29 mm) and downward (1.68 6 0.30 mm)(P\0.001). The nasolabial angle increased significantly(16.12� 6 1.31�). Subnasale, however, showed neitherstatistical nor clinical significant positional changes inthe vertical and horizontal directions.

When the relationships between hard-tissue andsoft-tissue changes were examined by using the Pearsoncorrelation analysis, both the backward movement of themaxillary central incisor tip, (P\0.01) and the bendingmovement of the maxillary anterior alveolar ridge(P\0.001) showed statistically significant correlationswith upper lip retraction (Nperp-Ls) (Table II). At thesame time, the increase in upper lip length (FH-Ls)closely correlated with the maxillary central incisortip’s downward movement (linear FH-U1) (P \0.001)as well as backward movement (angular FH-U1)(P\0.05). Despite a statistically and clinically significant


Fig 5. Cephalometric landmarks of hard-tissue and soft-tissue points and associated reference planes: S, Sella;Na, nasion; Or, orbitale; Po, porion; ANS, anterior nasalspine;PNS, posterior nasal spine; A, subspinale;U1, max-illary central incisor; Sn, subnasale; Ls, labrale superius.

Fig 6. Hard-tissuemeasurements::FH to U1, Angle be-tween the axis of the maxillary central incisor and the FHplane; FH to U1, distance from the maxillary central inci-sor to the FH plane; Nperp to U1, distance from maxillarycentral incisor tip to nasion perpendicular; FH to A, dis-tance from A-point to the FH plane; Nperp to A, distancefrom A-point to nasion perpendicular; SNA, S-N plane toN-A line; UARA, upper alveolar ridge angle, the angle be-tween the upper alveolar ridge line and the FH plane; U1,maxillary central incisor.

e256 Choo et al

change of the nasolabial angle between pretreatmentand posttreatment, no hard-tissue variable changes re-flected statistically significant correlations with the na-solabial angle. The linear and angular changes of PointA also failed to show statistically significant correlationswith any soft-tissue variable changes.

There were correlations between the corticotomymeasurements and the hard-tissue and soft-tissuechanges (Tables III, Fig 8).

The buccal corticotomy width and palatal cortico-tomy width correlated positively with the change of an-gular FH-U1. In addition, buccal corticotomy widthpositively correlated with the maxillary alveolar ridgeangle change. Buccal corticotomy width, however, neg-atively correlated with the value changes of linear FH-U1, Nperp-A, SNA, and FH-Ls. The retained cancellouslength correlated positively with the changes of Nperp-A and SNA and negatively with the changes of angularFH-U1, Nperp-U1, and maxillary alveolar ridge angle.

DISCUSSION

All patients were completely compliant with theorthopedic en-masse retraction protocol after the peri-segmental corticotomy. The duration of the final


orthodontic adjustments after the orthopedic retractionvaried significantly depending on the patient’s situation.One patient became pregnant and suspended the speedysurgical orthodontic therapy for more than 1.5 years,whereas 2 other patients suspended the treatment intheir final stage of speedy surgical orthodontic therapyto study abroad for an extended time.

Among the different variations of the surgically assis-ted orthodontics, speedy surgical orthodontics is distin-guished by the following 2 characteristics.

Buccal and palatal perisegmental corticotomies

The surgical plan of speedy surgical orthodontic ther-apy includes buccal and palatal perisegmental corticot-omies to designate the maxillary 6 anterior teeth as theretracted unit, and the horizontal perisegmental cortico-tomy site serves as the fulcrum for bone bending of theretracted unit. Comparatively, the surgical design ofcorticotomy-facilitated orthodontics uses a perisegman-tal corticotomy around 1 tooth to create block bonemovement to facilitate individual tooth movement.


Fig 7. Soft tissue measurements: FH to Ls, Distancefrom Ls to the FH plane; Nperp to Ls, distance from Lsto nasion perpendicular; FH to Sn, distance from Sn tothe FH plane; Nperp to Sn, distance from Sn to nasionperpendicular; NLA, nasolabial angle, the angle formedby the labial surface of the upper lip at the midline andthe inferior border of the nose.

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The surgical plan of accelerated osteogenic orthodonticsuses numerous perforation corticotomies around eachtooth to produce Frost’s regional acceleratory phenom-enon effect,24,25 which is in turn used to facilitateindividual tooth movement (described by Sebaounet al,30 presenting the systemic and histologic evidencethat tooth movement is facilitated after multiple corti-cotomies around the tooth, attributed to a demineraliza-tion and remineralization phenomenon rather thana bony block movement). The perisegmental cortico-tomy of Chung’s speedy surgical orthodontic is used toproduce the bone-bending effect of a multiple tooth-embedding bony block.11,17 A perisegmental linearcorticotomy site can provide a focal force-loadingzone for heavy orthopedic force by breaking the stressdistribution over the cortical bone.20 Frost’s regional ac-celeratory phenomenon effect is, of course, also appliedto corticotomy-facilitated orthodontics and speedy sur-gical orthodontics.13-18,27,28 More specifically, after thespeedy surgical orthodontics 3 to 6 months of theorthopedic retraction phase, the final phase oftreatment is geared toward detailing the occlusion


through conventional orthodontic forces andbiomechanics. This orthodontic phase typically occursin the regional acceleratory phenomenon’s effectivetime frame, enabling the facilitated tooth movement.Recently, Lee et al31 investigated the pattern of acceler-ated tooth movement in 3 orthodontic therapy protocolsin animal models: orthodontic tooth movement with nosurgical intervention, treatment combined with a peri-segmental linear corticotomy, and treatment combinedwith an anterior segmental osteotomy. They reportedthat the regional acceleratory phenomenon was ob-served only in the corticotomy-treated group, and a dis-traction osteogenesis effect was observed in the anteriorsegmental osteotomy-treated group.

Heavy orthopedic retraction against a palatalminiplate anchorage

Speedy surgical orthodontic uses a heavy orthopedicforce to retract the maxillary anterior segment.15,16 Theapplication of heavy forces in maxillary retraction wasstudied in an animal model with monkeys byKawakami et al19 and Yoshikawa20 in Japan. They re-ported that a corticotomized maxillary segment couldbe effectively retracted using a heavy force of 400 gper side without damage to the intraoral or extraoralsoft tissues, inferring that the orthopedic force aftera perisegmental corticotomy could clinically apply tohumans. In speedy surgical orthodontics’maxillary ante-rior retraction, no tooth-borne anchorage was used. Thiswas to eliminate the possibility of unwanted mesialmovement of the maxillary posterior teeth in the treat-ment of maxillary protrusion. Instead, the constantheavy force was generated against a palatal miniplateproviding the absolute intraoral anchorage and trans-mitted to the perisegmental corticotomy site througha rigid C-palatal retractor bonded to the palatal surfaceof the 6 maxillary anterior teeth.15 As shown in a recent3-dimensional finite element analysis study, the stressgenerated by the heavy orthopedic force is concentratedmore on the corticotomized site with relatively even dis-tribution over the retracted segment during the speedysurgical orthodontic maxillary retraction.32

Although the surgical design and the orthodonticbiomechanical setup of speedy surgical orthodonticswere introduced by Lee et al13 in 1999, our study isthe first to quantify the treatment outcomes of speedysurgical orthodontics by using statistical analyses. Thefact that all subjects in our study were women was un-intentional. It was simply because most patients whoelected speedy surgical orthodontic therapy werewomen, and we could obtain a sufficient number ofsubjects from that group. Since the time required for


Fig 8. A, Corticotomy measurements from lateral cephalograms; B, schematic illustration. BCW, Buc-cal corticocotomized width (mm); PCW, palatal corticotomized width (mm); RCL, residual cancellouslength, the distance between the deepest point of the buccal corticotomy and the deepest point ofthe palatal corticotomy (mm).

Table I. Changes of hard-tissue and soft-tissue measurements

T1 T3 T3�T1

P valueMean 6 SD Mean 6 SD Mean 6 SDHard-tissue measurementsFH-U1 (�) 120.73 6 6.83 101.00 6 6.88 �19.73 6 1.17 0.000*FH-U1 (mm) 62.45 6 3.86 63.62 6 3.44 1.17 6 0.36 0.003y

Nperp-U1 (mm) 8.79 6 3.89 �0.39 6 4.21 �9.19 6 0.31 0.000*FH-A (mm) 35.77 6 2.87 36.21 6 2.89 0.43 6 0.11 0.001y

Nperp-A (mm) 0.00 6 2.82 �1.12 6 3.05 �1.12 6 0.13 0.000*SNA (�) 80.77 6 2.27 79.77 6 2.21 �1.00 6 0.13 0.000*UARA (�) 116.12 6 6.71 102.14 6 7.93 �13.97 6 1.04 0.000*

Soft-tissue measurementsFH-Sn (mm) 33.60 6 2.84 33.70 6 2.89 0.10 6 0.07 0.175Nperp-Sn (mm) 12.94 6 3.18 12.84 6 3.28 �0.10 6 0.06 0.125FH-Ls (mm) 51.50 6 4.24 53.18 6 3.87 1.68 6 0.30 0.000*Nperp-Ls (mm) 19.37 6 3.71 14.77 6 4.22 �4.60 6 0.29 0.000*NLA (�) 89.90 6 10.97 106.03 6 10.25 16.12 6 1.31 0.000*

T1, Pretreatment; T3, posttreatment.Statistically significant differences between groups by paired t tests: *P\0.001; yP\0.01.

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the en-masse orthopedic retraction ranged from only 3to 6 months with minimal variations, we defined post-treatment as the time point when the orthopedic retrac-tion was completed, rather than the time point when thetotal orthodontic treatment was completed, to more ac-curately assess the soft-tissue and hard-tissue changesby speedy surgical orthodontic therapy. Each patient’spersonal and social situation often extended the totaltreatment time. The mean total treatment time for thesubjects in this study was 20 months with a range of11 to 42 months, which did not show significant differ-ences compared with conventional orthodontic therapywith 4 premolar extractions.

However, the primary goal of speedy surgical ortho-dontics is not to shorten the total treatment time; rather,it is to present a novel alternative to the conventional or-thognathic surgery-based orthodontic therapy undergeneral anesthesia. Speedy surgical orthodontic therapy


corrects the adult’s severe maxillary protrusion withgradual bending of the retracted maxillary bony seg-ment after decreasing the cortical bone’s resistance tothe heavy retraction force.

A block bone movement embedding multiple teethmight contribute to reducing the periodontal complica-tions related to the extensive retraction of the maxillaryteeth because significant retractions of the maxillary in-cisors in speedy surgical orthodontics are achieved bybone bending without changing the preexisting peri-odontal environment of the retracted teeth. In our pa-tient population, there were no self-reported medicalcomplications such as loss of tooth vitality, severe rootresorption, or periodontal damage during or after thecomplete orthodontic treatment. However, we recognizethe importance of periodontal stability before and afterspeedy surgical orthodontic therapy and intend to in-clude periodic periodontal assessments as part of the


Table II. Correlation coefficients between hard-tissue and soft-tissue changes (T3-T1)

Soft tissue

Hard tissue

DFH-U1 (�) DFH-U1 (mm) DNperp-U1 (mm) DFH-A (mm) DNperp-A (mm) DSNA (�) DUARA (�)DFH-Sn (mm) �0.352 0.428* �0.277 0.300 0.256 0.217 �0.414*DNperp-Sn (mm) 0.037 �0.281 0.143 �0.611y �0.040 �0.006 0.240DFH-Ls (mm) �0.491* 0.651z �0.301 0.030 0.247 0.221 �0.357DNperp-Ls (mm) 0.242 0.064 0.542y 0.352 �0.062 �0.074 0.641z

DNLA (�) �0.210 0.042 �0.323 �0.212 �0.087 �0.122 �0.307

*P\0.05; yP\0.01; zP\0.001.

Table III. Correlation coefficients between changes and corticotomy measurements

Corticotomymeasurement(mean 6 SD, mm)

Hard-tissue changes Soft-tissue changes

DFH-U1(�)

DFH-U1(mm)

DNperp-U1(mm)

DFH-A(mm)

DNperp-A(mm)

DSNA(�)

DUARA(�)

DFH-Sn(mm)

DNperp-Sn(mm)

DFH-Ls(mm)

DNperp-Ls(mm)

DNLA(�)

BCW (3.23 6 0.79) 0.421* �0.552y 0.319 �0.263 �0.486* �0.557y 0.495* �0.213 0.283 �0.494* 0.062 0.195PCW (3.37 6 0.97) 0.447* �0.329 0.387 �0.053 0.022 0.068 0.354 �0.342 0.189 �0.316 0.317 �0.202RCL (7.30 6 2.48) �0.634z 0.339 �0.406* 0.116 0.685z 0.651z �0.432* 0.291 0.302 0.229 �0.119 �0.072

*P\0.05; yP\0.01; zP\0.001.

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speedy surgical orthodontic protocol to monitor the pa-tient’s periodontal health.

An incomplete cortical bone cut can make it difficultto move the targeted segment, increase the risk of rootresorption, and result in uncontrolled tipping of theanterior teeth during retraction. Special attention isrequired on the palatal rugae area, since the corticalbone is thicker there than in any other palatal area.The perisegmental corticotomy procedure must bemeticulously performed by an experienced surgeon toensure the success of the orthopedic and orthodontictherapy. Some surgeons elect to do both buccal andpalatal perisegmental corticotomies at the same timeas a 1-stage procedure.16 A 1-stage perisegmental corti-cotomy uses a blind tunneling approach via small inci-sions on the maxillary buccal vestibule to reach thepalatal side. A 2-stage perisegmental corticotomy oftengives the surgeon a better view and the patient moretime to heal. Therefore, a 2-stage approach can be lesstechnique sensitive with lower risks of tissue damageand more predictable outcomes.

The surgical procedure of speedy surgical orthodon-tics always includes luxation of the retracted segmentimmediately after the perisegmental corticotomy. Themethod of luxation, however, is quite different fromthat of accelerated osteogenic orthodontics. Whereasaccelerated osteogenic orthodontics applies an aggres-sive luxation force to facilitate tooth movement every2 weeks after the multiple cortical perforation aroundeach tooth, speedy surgical orthodontics’ luxation can


be described as a gentle but firm pressure on the cortico-tomized bony segment, 1 time immediately after the lastperisegmental corticotomy (often, the buccal cortico-tomy). Especially in a 2-stage perisegmental corticotomymethod, the luxation helps to disrupt the unwantedcallus formation at the first corticotomized site (palatalside). The orthodontist should be able to feel the bend-ing of the corticotomized bony segment at this time.Patients were also instructed to gently push the cortico-tomized segment 3 to 5 times a day in the buccolingualdirection. The patient was monitored by the orthodontistevery 3 weeks to maintain the optimal orthopedic forcelevel. Patients should immediately return to the clinic foradjustments if any retractor pad loosens, because retrac-tion occurs rapidly and any tooth not connected by theretractor will be left behind with a large gap.

The changes of the hard-tissue and soft-tissue vari-ables are dramatic in speedy surgical orthodontic ther-apy. The angle between the FH reference plane andthe axis of the maxillary central incisor decreased by19.7� on average. The maxillary alveolar ridge angle de-creased by 14.0�, and the protrusion of the maxillarycentral incisor decreased by 9.2 mm with a minimalextrusion of 1.2 mm. The upper lip protrusion also de-creased by 4.6 mm with the increased upper lip lengthby 1.7 mm. The nasolabial angle increased on averageby 16.1�. These results reflect that the dramatic angularchange of the axis of the maxillary central incisor wasmostly due to the dramatic maxillary alveolar ridge anglereduction by the bone-bending effect.


e260 Choo et al

Another interesting finding was that the maxillarycentral incisors were retracted over 9 mm, with an aver-age extrusion of 1.2 mm. Since the average distance be-tween the horizontal corticotomy line and the tip of themaxillary central incisor was at least 30 mm and the av-erage change of FH-U1 was 19�, pure rotation of thecorticotomized segment with the corticotomy site asthe fulcrum point would have caused at least 1.64 mmof downward movement of the maxillary central incisortip. The effect of less extrusion can be explained by thespeedy surgical orthodontics’ intraoral en-masse retrac-tion setup in 3 dimensions. As described in detail in the“Material and methods” section (Fig 1), the C-palatalminiplate is often positioned much higher than the pal-atal retractor. Therefore, this setup has an innate intru-sion vector of the retraction force. In reality, however,the palatal retraction arms are often adjusted to adaptto the contour of the anterior palate for the patient’scomfort; this reduces the vertical discrepancy betweenthe C-palatal miniplate and the point of retraction forceapplication, decreasing the magnitude of intrusion.Therefore, the length of the retraction arms plays a crit-ical role in determining the vector and the moment ofthe retraction force for the retracted segment. The lineof retraction force of speedy surgical orthodontic biome-chanics can be easily adjusted to approximate as closelyas possible to the center of resistance of the retractedsegment, minimizing the vertical positional change ofthe central incisors during retraction. Although 1.2mm of extrusion on average might indicate that theline of retraction force was still lower than the centerof resistance, it seems that the amount of average extru-sion would have been greater without the inherent intru-sion component of the speedy surgical orthodonticbiomechanical setup for retraction.

An unexpected finding was that the positional andangular values of Point A did not show clinically signif-icant changes, even though the value changes were sta-tistically significant. This finding can be explained by thefact that the horizontal portion of the buccal periseg-mental corticotomy was quite often at or near Point A,and the anterior alveolar bone bending might have ac-crued around it with Point A as the fulcrum. In addition,the use of a labial spring retractor to better control theanterior torque of the retracted segment could have sup-pressed the significant positional and angular changesof Point A.

As expected, subnasale was the only landmark thatdid not show statistically and clinically significant posi-tional changes by speedy surgical orthodontic therapy.Although a conventional LeFort I osteotomy occursabove the level of the anterior nasal spine and signifi-cantly affects the position of the nasal base after surgery,


the surgical level of the perisegmental corticotomy ismuch lower than the anterior nasal spine level. There-fore, subnasale, the soft-tissue counterpart of anteriornasal spine, must have had the least influence fromthe speedy surgical orthodontic therapy.

The correlation coefficient results of soft-tissue andhard-tissue changes identified 2 variables most closelycorrelated with the upper lip retraction. The first wasthe retraction of the maxillary central incisors, and thesecond was the bending of the corticotomized alveolarridge. In addition, upper lip length was shown to havea positive correlation with extrusion of the maxillarycentral incisor and a negative correlation with retroclina-tion of the maxillary central incisors. These results arepartly in agreement of other studies reporting correla-tions between incisor movement and their overlyingsoft-tissue changes.32-34 For example, Talass et al34 re-ported thatmaxillary incisor retraction has a significantlypositive effect on upper lip retraction, lower lip length-ening, and nasolabial angle.

The results of the Pearson correlation coefficient testindicated that all linear soft-tissue changes had somestatistically significant correlations with the hard-tissuechanges. However, the nasolabial anble change (theonly angular soft-tissue change) showed no statisticallysignificant correlation with any hard-tissue changes, al-though the nasolabial angle showed clinically dramaticchanges by speedy surgical orthodontic therapy. Thiswas an unexpected result; however, when we expandedthe correlation analysis to include soft-tissue changes,the nasolabial angle change showed a statistically signif-icant correlation with another linear soft-tissue change(Nperp-Ls angle; coefficient, 0.66298; P 5 0.0004).This result showed that a favorable nasolabial anglechange was primarily related to the upper lip change.This correlation analysis also identified that the 2 mostcritical changes of hard-tissue variables that must haveinfluenced the significant upper lip retraction were re-traction of the maxillary central incisors and bendingof the maxillary anterior alveolar ridge. Of note, thesehard-tissue changes did not necessarily correlate withthe nasolabial angle change, but a visible associationtrend could be detected. This area of investigation couldbe explored by including additional test variables.

To investigate the relationships between the regionalspecifications of maxillary corticotomy and the changesof soft-tissue and hard-tissue variables, a lateral cepha-logram was taken for each patient immediately after thecorticotomy (Fig 8). Table III clearly illustrates thata wider buccal corticotomy achieves more retroclinationof the maxillary central incisors as well as that of themaxillary anterior alveolar ridge. On the other hand,a wider buccal corticotomy results in less retraction of


Choo et al e261

Point A. In addition, it seems that the increase of upperlip length and the extrusion of the maxillary central in-cisors are less severe if the buccal corticotomy is wider.These results might be because the orthopedic retractionforce is generated against the miniplate on the roof ofthe mouth, causing the line of retraction force to belower than the center of resistance of the retracted seg-ment. Consequently, a wider buccal corticotomy accom-modates more room into which the maxillary anteriorsegment can move after the intrusive retraction force.Although the width of the palatal corticotomy had a sta-tistically significant positive correlation with the amountof retroclination of the maxillary central incisors, it didnot show a statistically significant correlation with anyother hard-tissue or soft-tissue changes. This might bebecause the dimensions of the palatal corticotomywere, in general, less consistent than those of the buccalcorticotomy caused by the difficulty of visualization dur-ing surgery.

As expected, the greater the amount of retained med-ullary bone after the buccal and palatal corticotomies,the less bending of the retracted segment was observed.In addition, the amount of retraction of the maxillarycentral incisor was shown to be less with greateramounts of retained medullary bone. An unexpectedfinding was a statistically significant positive correlationbetween the retained medullary bone and the change ofPoint A, suggesting that a greater Point A retraction canbe expected when the medullary bone is retained more.This result could indicate that the bone-bending effect ismore positively correlated with the width of the cortico-tomy on each side of the buccal or palatal bones ratherthan the thickness of the residual medullary bone (Fig8). With the limitations of conventional 2-dimensionalradiographic analysis of a 3-dimensional object, it willbe meaningful to investigate this relationship by using3-dimensional data analysis in the future.

The fact that all subjects of the current study weresomen was unintentional. It was simply because mostpatients who elected speedy surgical orthodontic ther-apy were female, and we could obtain enough subjectsfrom this population. Further studies are needed to com-pare the differences in treatment effects between maleand female patients as related to bone differences andhormonal differences in bone reorganization.

CONCLUSIONS

Speedy surgical orthodontic biomechanics enablesorthodontists to dramatically relocate the maxillary an-terior teeth beyond an average scope of orthodontictooth movement by establishing a unique intraoral bio-mechanical setup that can generate a constant heavy


orthopedic retraction force for a bone-bending effectof the corticotomized maxillary anterior segment. There-fore, speedy surgical orthodontics can serve as an alter-native treatment modality to conventional orthognathicsurgery or anterior segmental osteotomy-based ortho-dontic treatment for an adult’s maxillary or bimaxillaryprotrusion.

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