ORIGINAL ARTICLE

Comparative evaluation of maxillary protractionwith or without skeletal anchorage

Ca�gla Sar,a Ayca Arman-€Ozcırpıcı,b Sina Uckan,c and A. Canan Yazıcıd

Ankara, Turkey

FromaPostgbAssocProfedAssisThe aucts oReprinFak€ule-maiSubm0889-Copyrdoi:10

636

Introduction: The aim of this prospective clinical study was to evaluate the skeletal, dentoalveolar, and soft-tissue effects of maxillary protraction with miniplates compared with conventional facemask therapy and anuntreated Class III control group. Methods: Forty-five subjects who were in prepubertal or pubertal skeletalgrowth periods were included in the study and divided into 3 groups of 15 patients each. All subjects had skeletaland dental Class III malocclusions with maxillary deficiency, vertically normal growth pattern, anterior crossbite,Angle Class III molar relationship, normal or increased overbite, and retrusive nasomaxillary complex. Beforemaxillary protraction, rapid maxillary expansion with a bonded appliance was performed in both treatmentgroups. In the first group (MP1FM), consisting of 5 girls ande 10 boys (mean age, 10.91 years), facemaskswere applied from 2 titaniumminiplates surgically placed laterally to the apertura piriformis regions of themaxilla.The second group (FM) of 7 girls and 8 boys (mean age, 10.31 years) received maxillary protraction therapy withconventional facemasks applied from hooks of the rapid maxillary expansion appliance. The third group of 8 girlsand 7 boys (mean age, 10.05 years) was the untreated control group. Lateral cephalometric films were obtainedat the beginning and end of treatment or observation in all groups and analyzed according to a structural super-imposition method. Measurements were evaulated statistically withWilcoxon and Kruskal-Wallis tests.Results:Treatment periods were 6.78 and 9.45 months in the MP1FM and FM groups, respectively, and the observationperiod in the control group was 7.59 months. The differences were significant between the 3 groups (P\0.05)and the MP1FM and FM groups (P\0.001). The maxilla moved forward for 2.3 mm in the MP1FM group and1.83mm in the FM group with maxillary protraction. The difference was significant between 2 groups (P\0.001).The protraction rates were 0.45 mm per month in the MP1FM group and 0.24 mm per month in the FM group(P \0.001). The maxilla showed anterior rotation after facemask therapy in the FM group (P \0.01); therewas no significant rotation in the MP1FM group. Posterior rotation of the mandible and increased facial heightwere more evident in the FM group compared with the MP1FM group (P\0.01). Both the maxilla and the man-dible moved forward significantly in the control group. Protrusion and mesialization of the maxillary teeth in theFM group were eliminated in the MP1FM group. The maxillomandibular relationships and the soft-tissue profilewere improved remarkably in both treatment groups. Conclusions: The undesired effects of conventionalfacemask therapy were reduced or eliminated with miniplate anchorage, and efficient maxillary protractionwas achieved in a shorter treatment period. (Am J Orthod Dentofacial Orthop 2011;139:636-49)

Class III malocclusions are considered to be amongthemost challenging orthodontic problems to treat.The prevalence of Class III malocclusions is approx-

imately 1% to 5% in white populations.1,2 However, in

the University of Baskent, Ankara, Turkey.raduate resident, Department of Orthodontics, Faculty of Dentistry.ciate professor, Department of Orthodontics, Faculty of Dentistry.ssor, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry.tant professor, Department of Biostatistics, Faculty of Medicine.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.t requests to: Ayca Arman-€Ozcırpıcı, Baskent €Universitesi, Dis Hekimli�gitesi, Ortodonti Anabilim Dalı, 06490 Bahcelievler-Ankara, T€urkiye;l, ayca@baskent.edu.tr.itted, April 2009; revised, May 2009; accepted, June 2009.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2009.06.039

Asian populations, the incidence of this malocclusion isas high as 14%.3-5 A Class III malocclusion might be dueto mandibular prognathism, maxillary retrognathism,protrusive mandibular dentition, retrusive maxillarydentition, and a combination of these components.6-10 Ithas been reported that two thirds of skeletal Class IIImalocclusions are due to either maxillary retrognathismor a combination of maxillary retrognathism andmandibular prognathism.6-10

Early treatment is commonly indicated to obtaina more normal jaw relationship. A facemask is thoughtto be an effective treatment approach for skeletal ClassIII patients with maxillary deficiency.The results of pre-vious clinical studies have indicated that the applicationof an orthopedic force with a protraction facemask tothe craniofacial complex during the early phase of

Sar et al 637

growth can contribute to the treatment of Class III mal-occlusion.11-15 The principle of maxillary protraction isto apply an anteriorly directed force on thecircummaxillary sutures, which are still patent at anearly age and thereby stimulate bone apposition in thesuture areas.

A tooth-borne device bonded to the maxillary teeth isthe point of force application, and the forehead and thechin are the anchorage sources for protraction in face-mask theapy. The effects of maxillary protraction includeanterior movement of the maxilla and the maxillarydentition, accompanied by counterclockwise rotation,lingual inclination of the mandibular teeth, and clock-wise rotation of the mandible, causing the chin tomove downward and backward. Lower anterior facialheight increases while overbite decreases.16-23 Theseeffects tend to turn a Class III malocclusion intoa Class I malocclusion and produce an orthognathicprofile in a short time. However, indirect application offorce limits the potential for orthopedic change andinevitably causes undesirable tooth movements such asmesial movement and extrusion of the maxillarymolars and labial tipping of the maxillary incisors.

There is a need for a stable anchorage to transfer theforce directly to the circummaxillary sutures, thuseliminating the undesirable dental effects and obtainingmajor skeletal effects. Orthopedic anchorage for maxillaryprotraction is a newarea of research, and investigations onthis subject are limited. Ankylosed tooth, osseointegratedimplants, titanium screws, and onplants have beenused asstable anchorage in previous case reports.24-27 Titaniumminiplates have been shown to provide absoluteanchorage when orthopedic forces were applied withfacemasks in some clinical studies.28-32

To date, however, there is a lack of knowledge on thecomparative effects of maxillary protraction with orwithout skeletal anchorage. Since there is no study inthe literature, in this prospective study, we attemptedto evaluate the skeletal, dentoalveolar, and soft-tissueeffects of maxillary protraction with miniplates com-pared with conventional facemask therapy and an un-treated Class III control group.

MATERIAL AND METHODS

Forty-five subjects from the Department of Ortho-dontics, Faculty of Dentistry, University of Baskent inAnkara, Turkey, were included in this study. All subjectswere between the PP2 5 and MP3cap developmentalstages at the beginning of the treatment or the controlperiod according to their hand-wrist radiographs.33

The patients were selected by the following inclusion cri-teria: (1) skeletal and dental Class III malocclusion withmaxillary deficiency (ANB, \0�; Nperp-A, \1 mm;

American Journal of Orthodontics and Dentofacial Orthoped

Wits apprasial, \–2 mm); (2) vertically normal growthpattern (SNGoGn, \40�); (3) anterior crossbite andAngle Class III molar relationship; and (4) normal orincreased overbite and retrusive nasomaxillary complex.All subjects and parents were informed of the experi-mental protocols and signed an informed consentform that was previously approved by the ethics commit-tee of the University of Baskent. The selected patientswere divided into 3 groups of 15 patients each.

In thefirst group (MP1FM) consisting of 5 girls and 10boys (mean age, 10.91 years), facemasks were appliedfrom 2 titanium miniplates (OsteoMed, Addison, Tex)surgically placed laterally to the apertura piriformisregions of the maxilla. Subjects without anchorage teethfor the application of facemask, depending on congenita-lIy missing teeth or early removal of posterior deciduousteeth, were given priority for inclusion in this group.I-shaped titaniumminiplates, used for fixation inmaxillo-facial surgery, with 3 holes were placed by the same max-illofacial surgeon (S.U.) under local or general anesthesia.A mucoperiosteal incision was made at the labial vestibulebetween the maxillary lateral incisors and canines, anda mucoperiosteal flap was elevated to expose the lateralnasalwall of themaxilla onboth sides. An appropriate cor-tical bone area was found to adapt the miniplates aroundthe apertura piriformis, and special care was taken not todamage the erupting canines. Miniplates were thenshaped according to the anatomic structures and fixedin position with 2 monocortical miniscrews (diameter,1.5 mm; length, 7 mm). The incisions were sutured with3.0 polyglactin 910 exposing the third hole into the oralcavity (Fig 1). After a 1-week period to allow soft-tissuehealing, protraction forces were applied with elasticsfrom the hooks of the miniplates to the facemasks (Fig 2).

The second group (FM) of 7 girls and 8 boys (meanage, 10.31 years) received maxillary protraction therapywith conventional facemasks applied from the hooks ofthe rapid maxillary expansion (RME) appliance.

To distinguish the treatment changes from normalgrowth changes, the third group of 8 girls and 7 boys(mean age, 10.05 years) was the untreated Class III con-trol group. The subjects of the control group matchedthose in the treatment groups with regard to chronologicage, skeletal development, and craniofacial morphology.

Before maxillary protraction, a bonded RME appliancewith hooks was applied in both treatment groups. Themidline expansion screw (1114/10, Lewa, Remchingen,Germany) of the RME appliance was activated twice perday for 7 days until the midpalatal suture was disturbed,and expansion was continued with a semirapid protocol(RME of 7 days, followed by slow maxillary expansion) inpatients with continuing maxillary transverse deficiencyuntil the desired expansion was achieved.34 Immediately

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Fig 1. A, Mucoperiosteal incisions made at the labial vestibule of the maxilla on both sides; B and C,adaptation and fixation of miniplates to lateral nasal walls of the maxilla; D, sutures exposing the thirdhole into the oral cavity before maxillary protraction.

638 Sar et al

after the maxillary sutural system was disrupted, thepatients were given Petit-type facemasks (716-0001,Ormco, Glendora, Calif). The facemask protocol was thesame for both treatment groups. Elastics, directed 20� to30� downward from the occlusal plane, delivered a forceof 400 g per side, as determined by a force gauge. Thepatients were instructed to wear their facemasks at least16hours per day, and facemask therapywas continued un-til at least a 4-mm overjet was achieved. Later, all patientshad retention treatment with facemasks or chincaps, andsome were treated with fixed appliances subsequently.

Lateral cephalometric films were obtained at the startof the maxillary protraction or the observation period(T1) and at the end of the active treatment or the obser-vation period (T2) in all groups and were hand-traced onorthodontic tracing paper on a conventional light box byusing a 0.3-mm lead pencil and measured by the sameinvestigator (C.S.) under optimal conditions. For theevaluation of the lateral cephalometric radiographs, inaddition to the conventional reference planes, horizontal(HR) and vertical (VR) reference planes were constructedfor some linear and angular measurements. A horizontalline constructed by subtracting 7� from the sella-nasionline was used as the HR plane. A vertical line passingthrough sella and perpendicular to the HR plane wasthe VR plane (Figs 3-5). The lateral cephalometricradiographs taken at T2 were superimposed on thosetaken at T1, on stable cranial structures, by using the

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total structural superimpositioning method.35 Thesereference structures were the contours of the anteriorwall of sella turcica, the anterior contours of the mediancranial fossa, the intersection of the anterior contour ofsella and tuberculum sella, the inner surface of the fron-tal bone, the contours of the cribriform plate, the con-tours of the bilateral fronto-ethmoidal crests, and thecontour of the median border of the cerebral surfacesof the orbital roofs. The HR and VR planes were trans-ferred from the T1 to the T2 radiographs. The sensitivityvalues of the linear and angular radiographic measure-ments were 0.5 mm and 0.5�, respectively.

Maxillary regional superimpositions were used tomeasure the movement of the maxillary dentition rela-tive to the maxillary basal bone.36 The maxillae weresuperimposed on the best fit of the lingual curvatureof the palatal plate and internal bony structures. To ex-amine the changes in the maxillary dentoalveolar struc-tures, a maxillary HR line (HRmx) was drawn along theANS-PNS line, and a vertical line passing through PNSand perpendicular to the HRmx was the maxillary VRplane (VRmx) (Fig 6).

Mandibular regional superimpositions were made onmandibular stable structures, according to the methoddescribed by Bj€ork and Skieller.35 The 2 radiographswere superimposed on the anterior contour of thechin, the inner contour of the cortical plate at the lowerborder of the symphysis, the trabecular structures inside

Journal of Orthodontics and Dentofacial Orthopedics

Fig 2. A, Intraoral view of the miniplates placed laterally to the apertura piriformis; B, extraoral frontalview of the application of a facemask via miniplates; C, profile view of the patient with a facemask.

Sar et al 639

the symphysis, the contour of the mandibular canal, andthe lower contour of a mineralized molar germ beforeroot development begins. To evaluate the changes,a line passing through gonion and gnathion was usedas the mandibular HR plane (HRmp), and a vertical linepassing through gonion, perpendicular to the HRmpserved as the mandibular VR plane (VRmp). The degreeof mandibular rotation was assessed by measuring theangle between the sella-nasion lines of the first and sec-ond radiographs on the superimposed tracings (Fig 7).

Cephalometric landmarks, reference planes and lines,and measurements are shown in Figures 3 through 7.

Statistical analysis

Statistical analysis was performed by using the Statis-tical Package for Social Sciences (version 13.0, SPSS,Chicago, Ill). The normality of the distribution of the var-iables was checked by using the Shapiro-Wilks test andthe homogeneities of the group variances by the Levene

American Journal of Orthodontics and Dentofacial Orthoped

test. Since variables were not normally distributed andsome groups’ variances were not homogeneous, theWilcoxon test was used to analyze the changes duringthe treatment or control periods, and the groups ineach period were compared with the Kruskal-Wallis1-way analysis of variance (ANOVA) by ranks test, andthen multiple comparisons between pairs of groupswere carried out according to the Dunn test. The resultswere expressed as means and standard deviations, me-dians, and minimum and maximum values. P \0.05was considered to be statistically significant.

Three weeks after the first measurements, thetracings and the measurements were repeated by thesame author on 30 lateral cephalograms of 15 randomlyselected patients. To assess the reliability of the mea-surements, the intraclass correlation coefficients (r)were calculated for each variable in the T1 and T2 ceph-alograms. The intraclass correlation coefficients rangedfrom 0.989 to 1.000. No significant differences were

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Fig 3. Maxillary and maxillomandibular skeletal mea-surements used in the study: 1, SNA (�); 2, HR-ANS(mm); 3, HR-PNS (mm); 4, HR.PP (�); 5, Cd-A (mm);6, A-VR (mm); 7, Nperp-A (mm); 8, ANB (�); 9, (A-VR)-(B-VR) (mm); 10, Wits (mm).

640 Sar et al

found between the first and second measurements ofthose randomly selected cephalograms.

RESULTS

Mobility was noted in 8 of the 30 miniplates at T2;however, only 2 were replaced with additional surgeriesduring the protraction therapy. The other 6 miniplatesshowed minimal mobility and were rigid enough towithstand the protraction forces, so they were used untilthe end of the treatment. Since 2 of the 30 miniplatesneeded to be replaced, the success rate was 93%.

Table I gives initial values of the 3 groups. There wereno significant differences between the groups at T1. Thedifferences between the changes through T2 to T1 in theMP1FM, FM, and control groups are shown in Table II.

The treatment durations were 6.78 and 9.45 monthsin the MP1FM and FM groups, respectively, and the ob-servation period in the control group was 7.59 months.The difference was significant among the 3 groups(P\0.05).

The maxilla moved forward 2.83 mm in the MP1FMgroup and 2.16 mm in the FM group with maxillary pro-traction. Protraction rate was estimated by dividing thetotal amount of protraction (A-VR) into the treatmentduration. The difference in protraction rates betweenthe MP1FM and FM groups was statistically significant

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(P\0.001) at 0.45 and 0.24mm per month, respectively.The forward movement of the maxilla (A-VR) was signif-icant in the control group (P \0.05). The changes inSNA, A-VR, Cd-A, and Nperp-A were statistically signif-icant between the treatment groups (P\0.001); whencompared with the FM group, the MP1FM groupdemonstrated significantly greater changes. The maxillashowed anterior rotation (HR.PP) after facemask therapyin the FM group, but there was no significant rotation inthe MP1FM group (P\0.001).

Regarding the mandibular skeletal measurements,the mandible was positioned downward and backwardsignificantly in both treatment groups (SNB, B-VR,Nperp-Pg, and Pg-VR). The changes in SNB andPg-VR were statistically different between the MP1FMand FM groups (SNB, P \0.05; Pg-VR, P \0.01) andwere more evident in the FM group. There was alsoa significant increase in the Cd-Gn measurement in thecontrol group (P\0.01), whereas no significant changeswere seen in the treatment groups. Posterior rotation ofthe mandible (SN.GoGn, HR.GoMe) was significantlygreater in the FM group when compared with theMP1FM group (SN.GoGn, P \0.001; HR.GoMe,P\0.01). True rotation of the mandible was evaluatedwith structural superimposition of the mandibles in allgroups. The mandible was rotated posteriorly in bothtreatment groups according to this superimposition,but the increase in the FM group was more pronouncedthan in the MP1FM group (P\0.01).

Anterior and total facial heights (ANS-Me, N-Me) in-creased significantly in the treatment groups, and thechanges were more evident in the FM group comparedwith the MP1FM group (P\0.001).

The skeletal changes in both the maxilla and themandible led to a significant improvement in the inter-maxillary sagittal relationship (Wits, ANB, [A-VR]-[B-VR]) in both treatment groups, whereas no significantdifference was seen between groups.

Overjet increased significantly in the treatmentgroups. The difference was statistically significant be-tween the treatment groups regarding maxillary incisorposition (U1i.PP, U1.HRmx) (P \0.001). The maxillaryincisors showed significant protrusion (U1.HRmx, U1i-HRmx) in the FM group (P\0.01), whereas significantretrusion was seen in the MP1FM group (P \0.05).On the other hand, the maxillary molars demonstratedsignificant mesialization in the FM group (P \0.05),and no significant changes were seen in the MP1FMgroup. The difference between the 2 groups was signif-icant (P \0.001). In addition, the mandibular incisorswere retracted significantly in both treatment groups(P \0.01). The proclination of the maxillary incisorswas statistically significant, whereas no significant

Journal of Orthodontics and Dentofacial Orthopedics

Fig 4. Mandibular skeletal measurements and facialheights used in the study: 1, SNB (�); 2, Cd-Gn (mm);3, B-VR (mm); 4, Pg-VR (mm); 5, Nperp-Pg (mm);6, HR.GoMe (�); 7, SN.GoGn (�); 8, BaNa.PtGn (�);9, S-Go (mm); 10, N-ANS (mm); 11, ANS-Me (mm);12, N-Me (mm); 13, S-Go/N-Me.

Fig 5. Soft-tissue and dentoalveolar measurementsused in the study: 1, A0-VR (mm); 2, UL-VR (mm); 3, LL-VR (mm); 4, B0-VR (mm); 5, Pg0-VR; 6, Sn-Me0 (mm);7, N0-Me0 (mm); 8, U1.PP (�); 9, L1.MP (�).

Sar et al 641

change was observed in the position of the mandibularincisors in the control group.

The soft-tissue profile and the sagittal lip relationshipwere improved remarkably in both treatment groups. Themeasurements associatedwith the soft-tissue A-point andthe position of the upper lip (A0-VR, UL-VR, Sn-Me0)showed significant forward movements in both treatmentgroups (P\0.01), whereas this movement was more evi-dent in the MP1FM group compared with the FM group(P\0.001). The lower lip and the chin (LL-VR, Pg0-VR)moved backward significantly in both treatment groups,and no significant difference was seen between thosegroups. The control group demonstrated significant for-ward movement of the upper lip, the lower lip, and thechin after the changes of underlying skeletal structures.

DISCUSSION

Lately, the use of skeletal anchorage has been reportednot only for dentoalveolar movements such as distaliza-tion, mesialization, intrusion, and extrusion, but also fororthopedic effects such asmaxillary protraction in skeletalClass III patients.24-32 Since the force is transmitted to themaxilla indirectly in conventional maxillary protractiontherapies, undesired effects such as anterior rotationof the maxilla, proclination of the maxillary incisors,

American Journal of Orthodontics and Dentofacial Orthoped

excessive forward movement, and extrusion of themaxillary molars have been reported.16-23 These effectscamouflage the malocclusion and conflict with the maingoals of the skeletal Class III treatment. Hence, totransfer the force directly to the circummaxillary sutures,and thereby to increase the skeletal effects of themaxilla and eliminate the dental movements, skeletalanchorage can be used. In recent years, a fewresearchers have shown that the maxilla can beeffectively protracted via ankylozed deciduous teeth,osseointegrated implants, titanium screws, onplants,and titanium miniplates.24-32

In this prospective, controlled clinical study, weattempted to use facemasks with titanium miniplatesthat were surgically placed laterally to the aperturapiriformis regions of the maxilla, thus to maximize theskeletal effects, decrease the anterior rotation of themaxilla by applying the force through the center of resis-tance, and eliminate the undesired dental effects. Also,the treatment effects of maxillary protraction withminiplate anchorage were evaluated comparativelywith conventional facemask therapy and an untreatedClass III control group.

In this study, all patients were at the prepubertal orpubertal stage of growth, and their mean chronologicages were 10.91, 10.31, and 10.05 years in MP1FM,FM, and control groups, respectively, at T1. Maxillaryprotraction has been recommended by many authors

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Fig 7. Mandibular dentoalveolar measurements withlocal superimpositions and true mandibular rotation:1, L1i-VRmd (mm); 2, L1i-HRmd (mm); 3, L1.HRmd (�);4, true mandibular rotation (�).

Fig 6. Maxillary dentoalveolar measurements with localsuperimpositions: 1, U1.HRmx (�); 2, U6-HRmx (mm);3, U6-VRmx (mm); 4, U1i-HRmx (mm); 5, U1i-VRmx.

642 Sar et al

to be started at earlier ages to achieve more skeletal ef-fects,11,14,16,37,38 whereas studies comparing the effectsof maxillary protraction applied in different skeletaldevelopmental stages reported similar skeletalresponses.39,40 Since this study was prospective, allgroups were homogeneous and similar with regard toskeletal pattern, skeletal development, and chronologicage before treatment. Only patients havingcongenitally missing teeth and early loss of deciduousposterior teeth in the mixed dentition stage wereincluded in the first group.No significant differenceswere noted for any variables at T1.

RME with a bonded appliance was performed in bothtreatment groups. RME has been advocated as a routinepart of facemask therapy in the correction of Class IIImalocclusions even in the absence of maxillary constric-tion.41,42 RME expands a narrow maxilla, correctsa posterior crossbite, increases arch length, and splintsthe maxillary dentition during protraction therapy.Additionaly, RME can disarticulate circummaxillarysutures to facilitate the forward movement of themaxilla via facemask therapy and lead to downwardand forward movement of A-point by approximately1 mm.41–43

In the MP1FM group, titanium miniplates werepreferred to be placed laterally to the apertura piriformisregion on both sides of the maxilla with 2 miniscrews.Since the miniplates were fixed with monocortical min-iscrews, there was no need to wait for osseointegration.This might be the major advantage of miniplate anchor-age compared with osseointegrated implants andonplants. In addition, they can be bent easily and with-stand orthopedic forces. One main reason for choosinga placement site laterally to the apertura piriformis re-gions of the maxilla was to apply protraction forces asclose as possible to the center of resistance (CR) of the

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nasomaxillary complex. Because it is anterior to the cir-cummaxillary sutures, the apertura piriformis was alsopreferred for stimulating downward and forwardgrowth of the maxilla, which grows parallel to the forcevector.

The major complications for the MP1FM group weremobility and inflammation during protraction. Two ofthe 30 miniplates were replaced during treatment be-cause of their instability. The placement site was nearthe apical region of the lateral incisors and erupting ca-nines; thus, the possible reason for the mobility mighthave been the quantity of cortical bone area in patientswith erupting canines. To prevent this complication, ap-plying miniplates to the zygomatic buttress could be analternative in patients with erupting canines. The otherpossible reasons for mobility might have been the appli-cation of an opposite force vector to the direction ofplacement of the screws and the patients’ poor oral hy-giene.

It was reported in many clinical studies that applyingthe force vector between the lateral incisor and thecanine with a direction of 30� to 45� might help to de-crease the amount of counterclockwise rotation of themaxilla.44–47 Despite modifying the location (molars,premolars, canines) and the direction of the forcevector, anterior rotation of the maxilla could not beprevented in conventional facemask applications. Theprotraction forces applied from the level of the

Journal of Orthodontics and Dentofacial Orthopedics

Table I. Mean values of measurements at T1 and comparison of groups with the Kruskal-Wallis and Dunn tests

MP 1 FM FM Control

Mean 6 SD Mean 6 SD Mean 6 SD

Parameter Median (range) Median (range) Median (range) PChronologic age (y) 10.91 6 1.22 10.31 6 1.52 10.05 6 1.14 NS

11.30 (9.00-12.30) 10.50 (8.50-13.10) 10.08 (8.50-12.08)Maxillary skeletal parametersSNA (�) 77.86 6 3.14 77.86 6 2.72 78.63 6 2.43 NS

77.50 (73.00-82.50) 79.00 (71.50-81.00) 78.50 (75.00-82.50)A-VR (mm) 60.60 6 3.19 60.40 6 3.60 60.83 6 2.49 NS

60.50 (55.00-66.50) 59.50 (52.00-66.00) 60.50 (57.00-65.00)Cd-A (mm) 80.80 6 3.86 79.50 6 3.87 78.90 6 4.12 NS

80.50 (72.50-87.50) 80.00 (72.50-86.50) 78.00 (70.50-84.00)NPerp-A (mm) �4.36 6 3.44 �4.53 6 2.92 �3.56 6 2.27 NS

�4.50 (�11-1.50) �5.00 (�10-0.50) �3.50 (�7.00-0)HR-ANS (mm) 43.13 6 3.57 41.36 6 2.53 41.80 6 2.92 NS

42.00 (38.50-50.50) 42.00 (37.00-45.00) 42.00 (36.00-46.00)HR-PNS (mm) 41.90 6 3.31 40.43 6 2.28 40.90 6 2.29 NS

41.50 (36.00-49.00) 40.00 (37.00-45.00) 40.00 (38.50-45.50)HR.PP (�) �1.53 6 4.18 �1.13 6 3.55 �1.03 6 2.68 NS

�2.00 (�10.00-6.50) �1.00 (�6.00-8.00) �2.00 (�4.00-5.00)Mandibular skeletal parametersSNB (�) 81.13 6 3.45 81.26 6 2.36 82.14 6 2.78 NS

80.50 (75.50-87.50) 82.00 (75.50-85.00) 82.00 (78.00-87.50)B-VR (mm) 62.93 6 5.39 62.50 6 4.48 63.86 6 4.18 NS

63.00 (52.00-72.00) 63.50 (49.50-67.00) 63.00 (57.00-71.50)Cd-Gn (mm) 111.96 6 5.64 107.76 6 5.30 108.30 6 6.30 NS

114.00 (100.0-120.0) 108.00 (101.0-116.5) 107.50 (99.0-118.0)NPerp-Pg (mm) 0.53 6 6.50 �1.90 6 3.48 0.63 6 5.09 NS

1.50 (�17.00-11.00) �2.00 (�7.50-3.00) 0.50 (�12.50-8.00)Pg-VR (mm) 63.90 6 6.21 63.23 6 5.59 64.30 6 4.88 NS

63.00 (53.50-74.00) 65.00 (48.00-69.50) 65.00 (56.50-72.00)SN.GoGn (�) 31.33 6 4.78 30.63 6 4.98 31.23 6 4.59 NS

32.00 (22.00-38.00) 30.00 (23.00-38.00) 31.00 (24.50-38.50)HR.GoMe (�) 26.80 6 4.68 26.00 6 4.98 26.46 6 4.73 NS

28.00 (18.00-34.00) 26.00 (18.00-33.00) 26.00 (19.00-34.00)BaNa.PtGn (�) 91.33 6 4.17 91.86 6 4.84 91.40 6 4.26 NS

91.50 (84.00-99.00) 92.00 (83.00-101.5) 93.00 (81.50-96.00)Facial heightsS-Go (mm) 71.36 6 4.84 69.53 6 4.03 68.96 6 3.35 NS

72.00 (64.00-80.00) 70.00 (62.50-76.50) 69.00 (63.00-74.50)N-Me (mm) 111.03 6 6.64 108.50 6 6.10 108.83 6 5.96 NS

111.00 (100.0-122.5) 108.00 (100.0-118.5) 110.00 (99.0-117.0)ANS-Me (mm) 59.83 6 4.55 58.63 6 4.20 58.66 6 4.02 NS

61.00 (52.00-69.00) 58.00 (52.00-65.00) 60.00 (53.00-67.00)N-ANS (mm) 51.20 6 3.64 49.86 6 2.91 50.16 6 3.06 NS

50.00 (46.50-59.50) 50.50 (45.00-54.00) 50.50 (44.00-54.00)S-Go/N-Me 0.63 6 0.03 0.63 6 0.04 0.63 6 0.03 NS

0.63 (0.56-0.71) 0.63 (0.54-0.70) 0.62 (0.56-0.70)Maxillomandibular parametersANB (�) �3.26 6 2.17 �3.40 6 2.35 �3.51 6 2.05 NS

�3.5 (�8.00- �1.00) �2.50 (�8.00-0.00) �3.50 (�7.00- �0.50)(A-VR)-(B-VR) (mm) �2.33 6 3.20 �2.10 6 3.02 �3.03 6 3.33 NS

�1.50 (7.00-3.00) �1.50 (�6.50-2.50) �3.50 (�7.50-2.00)Wits (mm) �8.50 6 3.25 �7.36 6 2.08 �8.83 6 3.09 NS

�9.00 (�13.00- �3.00) �8.00 (�10.00- �2.50) �8.00 (�16.50- �5.50)Dentoalveolar parametersOverjet (mm) �3.06 6 1.42 �3.63 6 0.89 �3.63 6 1.80 NS

�3.50 (�6.00- �1.00) �3.50 (�5.00- �2.50) �3.00 (�9.00- �2.00)

Sar et al 643

American Journal of Orthodontics and Dentofacial Orthopedics May 2011 � Vol 139 � Issue 5

Table I. Continued

MP 1 FM FM Control

Mean 6 SD Mean 6 SD Mean 6 SD

Parameter Median (range) Median (range) Median (range) POverbite (mm) 2.73 6 1.70 3.93 6 1.88 3.06 6 1.82 NS

2.50 (0.00-5.50) 4.00 (0.50-7.00) 3.00 (0.00-7.00)U1i-VRmx (mm) 43.80 6 3.08 41.66 6 3.81 43.73 6 5.21 NS

42.50 (40.00-51.00) 41.00 (34.50-50.00) 44.50 (31.00-51.00)U1i-HRmx (mm) 25.50 6 2.73 25.70 6 2.08 24.63 6 3.07 NS

25.50 (20.00-31.00) 25.00 (23.00-29.50) 25.00 (17.50-29.00)U1.HRmx (�) 114.60 6 5.87 110.83 6 6.44 113.20 6 7.13 NS

115.00 (105.0-126.0) 110.00 (102.0-126.0) 112.00 (102.50-128)U1.PP (�) 113.70 6 6.32 110.36 6 6.01 114.23 6 8.33 NS

114.00 (104.0-125.0) 110.00 (102.0-124.5) 112.00 (101.0-128.0)L1i-VRmd (mm) 62.16 6 3.98 61.73 6 3.46 62.50 6 4.40 NS

62.00 (54.50-68.50) 62.00 (53.00-67.00) 63.50 (54.00-68.50)L1.HR (�) 87.63 6 6.48 88.03 6 7.32 87.66 6 8.26 NS

87.00 (76.00-101.00) 87.00 (78.00-103.50) 87.50 (73.00-100.00)L1.MP (�) 84.96 6 6.97 85.43 6 8.50 84.93 6 7.58 NS

85.00 (72.00-100.00) 82.50 (74.00-103.50) 85.00 (73.00-97.00)U6-VRmx (mm) 16.80 6 4.40 14.70 6 2.78 17.40 6 3.23 NS

16.50 (11.00-24.50) 14.00 (10.50-20.00) 18.50 (10.00-22.00)U6-HRmx (mm) 18.46 6 3.73 19.50 6 2.29 18.83 6 2.15 NS

18.00 (11.00-23.00) 19.00 (16.00-24.00) 18.50 (15.50-23.00)Soft-tissue parametersN0-Me0 (mm) 118.46 6 7.50 115.40 6 5.73 116.80 6 6.80 NS

119.00 (108.0-132.0) 114.00 (106.0-127.0) 116.00 (106.5-132.0)Sn-Me0 (mm) 63.46 6 5.65 61.86 6 3.58 63.00 6 4.75 NS

64.00 (54.00-74.00) 61.00 (55.00-68.00) 63.00 (56.50-74.00)A0-VR (mm) 75.93 6 3.90 75.26 6 3.46 76.06 6 3.05 NS

77.00 (67.50-82.00) 74.50 (66.50-81.00) 74.50 (72.00-81.00)B0-VR (mm) 73.70 6 5.74 72.66 6 5.05 74.86 6 4.47 NS

73.00 (62.50-82.50) 74.00 (58.00-78.50) 73.50 (68.00-82.50)UL-VR (mm) 78.60 6 4.87 77.90 6 3.89 78.93 6 3.76 NS

78.50 (69.00-86.00) 78.00 (69.00-83.50) 78.50 (73.00-85.00)LL-VR (mm) 80.20 6 5.57 79.56 6 4.47 80.90 6 4.13 NS

80.00 (69.50-90.00) 80.00 (68.00-84.50) 80.50 (74.50-87.50)Pg0-VR (mm) 75.66 6 6.62 74.76 6 6.42 76.76 6 5.58 NS

75.00 (64.00-85.50) 76.50 (57.50-82.00) 79.00 (67.00-83.50)

NS, Not significant.

644 Sar et al

maxillary arch, above the CR, caused anterior rotationand forward movement of the maxilla. In our MP1FMgroup, force was applied from the apertura piriformisregion with a 30� pull downward to the occlusal plane,passing as close as possible to the CR; in the FMgroup, the protraction force was applied 30�

downward from the hooks of the RME appliance to theocclusal plane, above the CR.

When treatment durations were evaluated, signifi-cant differences were seen between the treatmentgroups (P\0.001). In theMP1FM group, treatment du-ration was 6.7 months, whereas it was 9.4 months in FMgroup. This difference might be due to different anchor-age units used in the groups. In addition, the observationperiod in the control group was 7.5 months.

May 2011 � Vol 139 � Issue 5 American

One major objective of this study was to evaluate the ef-fects of facemask therapy with skeletal anchorage compara-tivelywith tooth anchorage on the forwardmovement of themaxilla. The Point-A advancement of the maxilla has beenreported in many previous studies by using conventionalintraoral anchorage devices. Many investigators includingMermigos et al48 (SNA angle, 11.8�; A-point, 11.76mm), Baik21 (SNA angle, 11.5�; A-point, 12 mm), Nganet al45 (SNA angle, 11.4�; A-point, 11.9 mm), Armanet al17 (SNA angle, 11.83�; A-point, 12.11 mm), andNartallo-Turley and Turley49 (SNA angle, 12.35�,A-point, 13.34 mm) demonstrated these findings. In thisstudy, the forward movement of Point A was 2.16 mm,and the increase in theSNAanglewas1.83� in theFMgroup.Our results for this group agree with previous studies.

Journal of Orthodontics and Dentofacial Orthopedics

Table II. Changes in the groups, with the significance of changes in each group (Wilcoxon test) and comparison ofchanges in the groups wıth the Kruskal-Wallis and Dunn tests

MP 1 FM (1) FM (2) Control (3)

Mean 6 SD Mean 6 SD Mean 6 SD

Parameter Median (range) P Median (range) P Median (range) P H 1-2 2-3 1-3Treatment duration(y) 0.56 6 0.16 z 0.78 6 0.26 z 0.63 6 0.10 z

0.50 (0.30-0.80) 0.80 (0.40-1.30) 0.60 (0.50-0.80)Protraction rate(mm/mo) 0.45 6 0.20 0.24 6 0.18 0.05 6 0.08 z z z

0.41 (0.17-0.83) 0.20 (0.00-0.62) 0.05 (�0.08-0.27)Maxillary skeletal parametersSNA (�) 2.53 6 1.24 y 1.83 6 1.33 y 0.26 6 0.53 NS z z z

2.00 (1.00-5.50) 2.00 (0.00-4.00) 0.00 (�1.00-1.00)A-VR (mm) 2.83 6 0.93 y 2.16 6 1.38 y 0.44 6 0.69 * z z z

3.00 (1.50-5.00) 2.00 (0.00-5.00) 0.50 (�0.50-2.00)Cd-A (mm) 3.26 6 1.82 y 1.80 6 1.70 y 0.80 6 0.95 y z z z

3.00 (1.00-8.50) 1.50 (�1.50-6.00) 1.00 (�0.50-3.50)NPerp-A (mm) 2.53 6 1.31 y 1.76 6 1.36 y 0.30 6 0.59 NS z z z

2.00 (0.50-4.50) 1.50 (0.00-4.00) 0.00 (�1.00-1.50)HR-ANS (mm) 0.66 6 1.24 * 1.00 6 0.98 y 0.94 6 0.91 y NS

0.50 (�1.00-4.00) 1.00 (�1.50-2.00) 0.50 (�0.50-2.50)HR-PNS (mm) 1.50 6 0.65 y 2.24 6 1.19 y 0.80 6 0.84 y z z z

1.50 (0.50-3.00) 2.00 (0.00-4.00) 0.50 (0.00-2.50)HR.PP (�) 0.91 6 1.82 NS 1.63 6 1.51 y �0.20 6 1.19 NS z z z

1.00 (�3.00-4.00) 1.00 (�1.00-5.00) 0.00 (�2.50-1.50)Mandibular skeletal parametersSNB (�) �1.93 6 2.19 * �2.30 6 1.23 y 0.65 6 0.65 y * z z

�2.50 (�5.00-2.50) �2.50 (�4.00-0.50) 0.50 (0.00-2.00)B-VR (mm) �2.76 6 2.01 y �3.03 6 1.92 y 1.23 6 1.27 y NS z z

�2.50 (�5.50-0.50) �3.50 (�6.00-1.00) 1.50 (�1.00-3.50)Cd-Gn (mm) �0.30 6 2.15 NS 0.43 6 2.15 NS 1.86 6 1.12 y y z z

0.00 (�5.00-3.00) 0.50 (�3.00-4.00) 2.00 (0.50-4.50)NPerp-Pg (mm) �2.80 6 2.67 y �2.90 6 3.97 * 0.96 6 1.66 * NS z z

�3.00 (�7.00-2.50) �2.50 (�9.00-4.00) 0.50 (�2.00-5.00)Pg-VR (mm) �2.53 6 2.10 y �3.36 6 2.51 y 1.93 6 1.32 y y z z

�2.50 (�6.00-2.00) �3.50 (�7.00-1.00) 2.00 (0.00-4.50)SN.GoGn (�) 1.46 6 2.78 * 3.06 6 2.07 y �0.40 6 0.87 NS z z z

2.00 (�6.00-4.50) 3.00 (�1.00-6.00) 0.00 (�2.00-1.00)HR.GoMe (�) 1.86 6 2.10 y 2.76 6 1.98 y �0.03 6 0.83 NS y z z

2.50 (�3.00-5.00) 2.50 (0.00-7.50) 0.00 (�1.00-2.00)BaNa.PtGn (�) �1.90 6 2.14 * �3.13 6 2.48 y 0.53 6 0.81 * y z z

�2.50 (�4.00-5.00) �3.00 (�7.00-2.00) 0.00 (0.00-2.50)Mandibular rotation (�) 1.83 6 2.19 2.80 6 2.23 �0.20 6 1.42 y z z

3.00 (�4.00-4.00) 3.00 (�3.00-6.00) 0.00 (�3.00-2.00)Facial heightsS-Go (mm) 0.36 6 1.26 NS 1.23 6 1.98 * 1.06 6 1.29 y NS

0.00 (�1.50-3.00) 1.00 (�2.00-6.00) 1.00 (�1.00-3.50)N-Me (mm) 2.73 6 2.76 * 4.63 6 1.96 y 0.83 6 1.01 * z z z

3.50 (�5.50-5.00) 4.00 (2.00-9.00) 1.00 (�1.50-3.00)ANS-Me (mm) 2.10 6 1.79 y 3.96 6 1.74 y 0.10 6 0.91 NS z z z

2.00 (�2.00-5.00) 4.00 (0.50-7.00) 0.00 (�2.00-1.50)N-ANS (mm) 0.56 6 2.29 NS 0.70 6 1.29 NS 0.76 6 0.86 y NS

1.00 (�3.50-4.00) 0.50 (�1.00-3.00) 0.50 (�0.50-2.50)S-Go/N-Me �0.01 6 0.02 * �0.01 6 0.01 y 0.00 6 0.01 NS NS z z

�0.02 (�0.05-0.03) �0.01 (�0.04-0.01) �0.01 (�0.05-0.03)Maxillomandibular parametersANB (�) 4.46 6 1.95 y 4.20 6 1.96 y �0.38 6 0.71 NS NS z z

4.00 (1.00-9.00) 5.00 (0.00-7.50) �0.30 (�1.50-0.50)(A-VR)-(B-VR) (mm) 5.66 6 2.24 y 5.06 6 2.16 y �0.78 6 1.22 * NS z z

5.50 (1.50-10.00) 5.00 (0.50-8.50) �0.50 (�3.50-1.20)

Sar et al 645

American Journal of Orthodontics and Dentofacial Orthopedics May 2011 � Vol 139 � Issue 5

Table II. Continued

MP 1 FM (1) FM (2) Control (3)

Mean 6 SD Mean 6 SD Mean 6 SD

Parameter Median (range) P Median (range) P Median (range) P H 1-2 2-3 1-3

Wits (mm) 5.43 6 1.69 y 6.56 6 2.88 y �0.53 6 1.14 NS y z z5.00 (3.00-9.00) 7.00 (1.00-11.50) �0.50 (�2.00-1.50)

Dentoalveolar parametersOverjet (mm) 7.66 6 1.61 y 7.93 6 1.65 y �0.33 6 0.72 NS NS z z

8.00 (4.00-10.00) 7.50 (5.00-11.50) �0.50 (�2.00-1.00)Overbite (mm) 0.33 6 2.17 NS �0.90 6 1.64 NS 0.26 6 0.62 NS NS

�0.50 (�2.00-5.50) �0.50 (�5.00-1.50) 0.00 (�1.00-1.50)U1i-VRmx (mm) �0.30 6 1.37 NS 1.86 6 1.32 y 0.53 6 0.85 * z z z

0.00 (�4.00-1.00) �2.00 (�1.00-4.00) 0.00 (0.00-2.50)U1i-HRmx (mm) 0.66 6 0.97 * 0.43 6 0.86 NS 0.33 6 0.44 * NS

0.50 (�1.00-2.50) 0.50 (�1.00-2.00) 0.00 (0.00-1.50)U1.HRmx (�) �2.36 6 3.54 * 2.73 6 4.46 * 0.90 6 1.15 y z y z

�1.50 (�10.00-2.00) 2.00 (�6.00-11.00) 0.50 (0.00-3.00)U1.PP (�) �0.83 6 3.95 NS 2.36 6 3.14 * 0.80 6 1.85 NS z z *

1.00 (-12.00-4.00) 3.00 (�3.50-8.00) 0.00 (�3.50-4.00)L1i-VRmd (mm) �3.93 6 2.59 y �2.96 6 1.45 y �0.13 6 0.63 NS * z z

�3.50 (�10.00- �1.00) �3.00 (�6.00- �1.00) 0.00 (�1.50-1.50)L1.HRmd (�) �7.16 6 3.12 y �7.06 6 3.86 y �0.43 6 1.51 NS NS z z

�7.00 (�13.00-0.00) �7.50 (�13.00-2.00) 0.00 (�4.00-3.50)L1.MP (�) �7.83 6 3.51 y �5.40 6 4.03 y �0.83 6 1.43 NS z z z

�7.00 (�14.00- �2.00) �4.50 (�16.50-2.00) �0.50 (�3.50-1.00)U6-VRmx (mm) �0.03 6 0.63 NS 1.93 6 2.35 * �0.20 6 0.64 NS z z NS

0.00 (�1.50-1.00) 2.50 (�4.00-5.00) 0.00 (�2.50-0.00)U6-HRmx (mm) 0.16 6 0.67 NS 0.60 6 1.12 * 0.00 6 0.00 NS NS

0.00 (�1.00-1.50) 0.50 (�1.00-4.00) 0.00 (0.00-0.00)Soft-tissue parametersN0-Me0 (mm) 1.66 6 3.79 NS 3.86 6 2.59 y 0.46 6 1.39 NS z z z

2.00 (�6.00-8.00) 4.00 (0.00-10.00) 0.00 (�2.00-4.00)Sn-Me0 (mm) 2.43 6 2.08 y 3.86 6 2.23 y 0.30 6 1.46 NS z z z

2.00 (�3.00-5.00) 4.00 (0.00-9.00) 0.00 (�2.00-3.00)A0-VR (mm) 3.36 6 1.20 y 2.66 6 2.17 y 0.90 6 0.91 y z z z

3.50 (1.00-5.50) 2.00 (0.00-6.50) 1.00 (�1.00-2.50)B0-VR (mm) �2.86 6 1.88 y �2.90 6 3.29 y 1.66 6 1.35 y NS z z

�2.50 (�6.00-0.00) �2.50 (�13.00-0.50) 2.00 (�0.50-4.00)UL-VR (mm) 3.43 6 1.76 y 2.63 6 2.74 y 0.83 6 1.09 * z z z

3.00 (1.00-7.00) 2.00 (�2.00-7.00) 1.00 (�1.00-3.00)LL-VR (mm) �1.33 6 2.12 * �1.16 6 2.41 NS 1.60 6 1.05 y NS z z

�1.00 (�5.50-2.00) �1.00 (�5.00-3.50) 2.00 (0.00-3.50)Pg0-VR (mm) �2.66 6 2.34 y �2.53 6 2.23 y 1.76 6 1.37 y NS z z

�2.00 (�6.00-0.50) �3.00 (�6.50-1.00) 2.00 (�0.50-4.00)

NS, Not significant; *P\0.05; yP\0.01; zP\0.001.

646 Sar et al

As for maxillary protraction with skeletal anchoragein the literature, few studies are available, and mostare case reports. Singer et al25 used a facemask withosseointegrated implants placed in the zygomatic but-tresses of the maxilla of a cleft-palate patient, and4 mm of forward and downward movement of the max-illa was achieved in 8 months. Similarly, Enacar et al26

applied a titanium screw to the alveolus to provide an-chorage in a patient with oligodontia and achieved3mm of anterior displacement in the ANS after 7 months

May 2011 � Vol 139 � Issue 5 American

of facemask therapy. Hong et al27 used an onplantplaced in the hard palate in an 11-year-old patient asabsolute anchorage and found 2.9 mm of maxillarydisplacement after the 12-month period of protraction.In their case reports, Kircelli et al29 and Zhou et al30

used titanium miniplates for maxillary protraction andreported 8 mm of protraction in 12 months and5.5 mm of protraction in 6 months, respectively. Liuet al28 demonstrated a technique named “sutural dis-traction osteogenesis” and placed bone-borne traction

Journal of Orthodontics and Dentofacial Orthopedics

Sar et al 647

hooks in bone holes, lateral to the apertura piriformisregions of 4 growing patients. Protraction forces wereapplied through the nostrils. Significant midfacialadvancement was reported with this method.

In a recent study, which was evaluated statistically,Kircelli and Pektas32 applied 6 miniplates to the lateralnasal walls of the maxilla in growing patients. Thenfacemasks were applied with miniplates. They found4.8 mm of maxillary advancement after 10.8 monthsof protraction therapy, and the protraction rate was0.44 mm per month. In our study, the forward move-ment of Point A in the MP1FM group was 2.83 mmin 6.7 months. When the difference of the treatmentdurations between the MP1FM and FM groups wasconsidered, evaluating the protraction rate would bemore meaningful (0.45 mm per month in the MP1FMgroup and 0.24 mm per month in the FM group). Thesefindings support the observations of Kircelli andPektas.32 It can be interpreted that almost twice asmuch protraction was found in MP1FM group whencompared with the FM group in the same duration.Applying the force directly to the maxilla, instead ofindirect application via the maxillary teeth and their sur-rounding periodontia in the MP1FM group, might bethe reason for this difference.

These findings in the FM group with regard to ante-rior rotation of the maxilla (HR.PP) show similarity withthe findings of previous studies in the literature. Anteriorrotation of the maxilla was statistically significant in theFM group (P\0.01), whereas no significant change wasseen in the MP1FM group. Applying the force vector asclose as possible to the CR in the MP1FM group mightbe the reason for elimination of the rotation of themaxilla when compared with the FM group.

Many authors have shown significant downward andbackward rotation of the mandible with facemasks. Inthis study, the posterior rotation of the mandible wassignificant in the MP1FM and the FM groups, whereasthe rotation in the FM group was more evident. The pos-sible explanation of this result might be the significantanterior rotation of the maxilla seen in the FM group,thus affecting the position of the mandible as well. Inaddition, the longer treatment duration in the FM groupmight be the other possible reason affecting the positionof the mandible. This might be due to the chincap effectof the facemask therapy. Accordingly, lower and total fa-cial heights increased significantly in both treatmentgroups, whereas greater changes were seen in the FMgroup compared with the MP1FM group. The findingsobserved in the FM group have been reported in previousstudies.

Proclination of the maxillary incisors, mesializationand extrusion of the maxillary molars, and retroclination

American Journal of Orthodontics and Dentofacial Orthoped

of the mandibular incisors, which are the main effects ofconventional facemask therapy with a tooth-bornedevice on dentoalveolar structures, were reported inmany previous studies.22,39,40,45,50 In our study, the FMgroup showed similar dentoalveolar findings asreported in previous studies. In the MP1FM group, themaxillary incisors showed significant retrusion, and themaxillary molars did not show any movement contraryto the facemask therapies with tooth-borne anchoragedevices. These findings agree with the observations offacemask therapies with skeletal anchorages. Thepossible explanation of our findings could be that theanchorage unit used in facemask therapy determinesthe movement of the maxillary teeth. The undesireddental effects of conventional facemask therapies wereeliminated with miniplate anchorage. Also, the mandib-ular incisors showed significant retrusion in both treat-ment groups from the chincap effect of the facemasks.

Improvements in the soft-tissue profile followed theunderlying skeletal components in both treatmentgroups. Since the increase in lower facial height (ANS-Me) was more evident in the FM group than in theMP1FM group (P\0.001), the FM group demonstratedsignificantly greater changes regarding the soft-tissuelower facial height (Sn-Me0) (P \0.001). In addition,the probable reason for the more forward movementof the upper lip in the MP1FM group might havebeen due to the significant forward movement of PointA when compared with the FM group.

The undesired effects of conventional facemask ther-apy, such as anterior rotation of the maxilla, posteriorrotation of the mandible, and increase in facial height,were reduced, and protrusion of the maxillary incisors,and mesialization and extrusion of the maxillary molarswere eliminated by the skeletal anchorage. In addition,more evident skeletal effects were obtained, and thetreatment duration was reduced significantly in theMP1FM group.

The potential application for this technique might befor growing skeletal Class III patients lacking anchorageteeth for the facemask because of congenitally missingteeth or the absence of posterior deciduous teeth in themixed dentition stage. Also, patients with increased verti-cal growth patterns could be another possible applicationof this method. Although there are many advantages ofmaxillary protractionwith skeletal anchorage, surgical op-erations when placing and removing miniplates are themajor disadvantages of this application. For this reason,clinicians should be cautious in selecting patients. In ad-dition, short-term facemask application after a LeFort Iosteotomy or a corticotomy could be advised for patientsat the postpubertal development period or for youngadults.

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648 Sar et al

Significant relapse potential has been reported instudies of the long-term effects of facemask therapies.Consequently, cephalometric variables should be reeval-uated in the long term.

CONCLUSIONS

This study was the first to evaluate the treatmenteffects of facemask therapy with skeletal anchoragecompared with conventional anchorage in a prospective,controlled, clinical study design. We made the followingconclusions.

1. The maxilla was effectively protracted without sig-nificant rotation in a shorter period of time in theMP1FM group when compared with the FM group.

2. The mandible demonstrated significantly greaterposterior rotation, and the increase in lower facialheight was more evident in the FM group.

3. The undesired dentoalveolar effects of conven-tional facemask therapies, such as mesializationand proclination of the maxillary teeth and extru-sion of the maxillary molars, were reduced oreliminated with miniplate anchorage placed later-ally to the apertura piriformis on both sides of themaxilla.

4. Maxillary protraction via miniplate achorage mightbe a promising early treatment approach in patientswith severe maxillary retrusion or a lack of anchor-age teeth for a facemask. Future studies are neededto examine the long-term stability of the changesrelated to the maxilla and the mandible.

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4. Allwright WC, Burndred WH. A survey of handicapping dentofacialanomalies among Chinese in Hong Kong. Int Dent J 1964;14:505-19.

5. Irie M, Nakamura S. Orthopedic approach to severe skeletal Class IIImalocclusion. Am J Orthod 1975;67:377-92.

6. Ellis EE, McNamara JA Jr. Components of adult Class III malocclu-sion. Am J Orthod 1984;85:277-90.

7. Nanda R. Biomechanical and clinical considerations of a modifiedprotraction headgear. Am J Orthod 1980;78:125-39.

8. Sanborn RT. Differences between the facial skeletal patterns ofClass III malocclusion and normal occlusion. Angle Orthod 1955;25:208-22.

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