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ORIGINAL ARTICLE

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Int the efhig f fixedinc 24 sub(m rotocome recordto tervapa y andce t (T1,tre treattre treatgro to sagwere found between treated subjects and controls at the end of the 2-phase treatment for all measurements.Counterintuitively, the bionator and high-pull headgear combination worsened the hyperdivergent facialpattern at a clinically significant level, as shown by analysis of final facial forms. The treated group exhibiteda stoprodim

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18ignificantly larger MPA value than controls (2.5) as well as a larger inclination of the Frankfort horizontalthe occlusal plane (2.8). Conclusions: Based on the analysis of this sample, the examined therapeutictocol does not appear to be a recommendable option for treatment of subjects with increased verticalensions. (Am J Orthod Dentofacial Orthop 2007;131:184-95)

he most common maxillary characteristics ofpatients with hyperdivergent facial patterns areexcessive maxillary anterior and posterior

dentoalveolar heights and flat palatal plane angles; theirmandibular characteristics are excessive mandibulardentoalveolar heights, increased lower anterior facialheights, steep mandibular plane angles, and short ramusheights, leading to retrusive positions of the mandi-ble.1-3 When treating a growing patient with a hyper-divergent facial pattern, orthodontic/orthopedic inter-vention is aimed to achieve 3 fundamental goals withregard to the vertical development of the face anddentition: to rotate the maxilla in a clockwise direction;to inhibit maxillary and mandibular posterior dentaleruption, allowing the mandible to rotate counterclock-wise; and to guide mandibular growth in an anteriorrather than a vertical direction.

Of the many protocols that have been suggested forthe treatment of hyperdivergent patients (conventionalfixed appliances combined with extractions,4 posteriorbite blocks with and without repelling magnets,5,6bonded acrylic splint expanders,7 vertical-pull chin-cups,8,9 high-pull facebows,10 and functional jaw or-thopedics11), a modality that at least theoretically couldaccomplish all of these goals simultaneously is abionator used with a high-pull facebow in growing

aduate Orthodontic Program, University of Michigan, Ann Arbor, Mich;ate practice, Fort Lauderdale, Fla.omas M. and Doris Graber Endowed Professor of Dentistry, Department ofhodontics and Pediatric Dentistry, School of Dentistry; professor of Cell andelopmental Biology, School of Medicine; research professor, Center foran Growth and Development, University of Michigan; private practice,Arbor, Mich.

sistant professor, Department of Orthodontics, University of Florence, Flo-e, Italy; Thomas M. Graber Visiting Scholar, Department of Orthodontics andiatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich.search professor, Department of Orthodontics, University of Florence,rence, Italy; Thomas M. Graber Visiting Scholar, Department of Orthodon-and Pediatric Dentistry, School of Dentistry, University of Michigan, Annor, Mich.vate practice, Endicott, NY.ported in part by funds made available through the Thomas M. and Dorisber Endowed Professorship, School of Dentistry, University of Michigan.rint requests to: Dr James A. McNamara, Department of Orthodontics andiatric Dentistry, University of Michigan, Ann Arbor, MI 48109-1078;ail, [email protected], November 2004; revised and accepted, April 2005.9-5406/$32.00yright 2007 by the American Association of Orthodontists.

:10.1016/j.ajodo.2005.04.043

4reatment effects of thecebow combination fo

ppliances in patients wertical dimensionsristopher S. Freeman,a James A. McNamara, Jr,b Td Theodore W. Graffe

n Arbor, Mich, Fort Lauderdale, Fla, Florence, Italy, and E

roduction: The purpose of this study was to evaluateh-pull facebow treatment followed by a second phase oreased vertical dimensions. Methods: The records ofean MPA value 30) treated consecutively with this pnts were compared with those obtained from 23 sets ofage, gender, vertical skeletal relationships, and time intients was from the University of Michigan Elementarphalograms were analyzed prior to the start of treatmenatment (T2, mean age 11.9 years), and after phase 2atment duration (phase 1, retention, and phase 2) for theup total time interval averaged 5.6 years. Results: Asionator and high-pullwed by fixedincreased

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fectiveness of a first phase of bionator andappliance therapy in growing subjects withjects with high-angle skeletal relationshipsl were examined. Cephalometric measure-s of an untreated group matched accordingls between records. The matched group ofSecondary School Growth Study. Lateralmean age 9.1 years), at the start of phase 2ment (T3, mean age 14.7 years). The totaled group was 5.5 years, whereas the controlittal relationships, no significant differences

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American Journal of Orthodontics and Dentofacial OrthopedicsVolume 131, Number 2

Freeman et al 185tients. Presumably, the high-pull facebow would helprotate the maxilla in a clockwise direction and inhibiteruption of the maxillary posterior dentition. At thee time, the acrylic of the bionator that is positioned

tween the maxillary and mandibular posterior teethsuming that it is thicker than the freeway space)uld further inhibit posterior dental vertical develop-nt. Also, the lingual flanges of the bionator would

use the patient to posture the mandible in a forwardsition (if desired) in an attempt to generate a moreterior direction of growth secondary to altered man-ular function.To date, the literature lacks information about the

ects of the bionator combined with high-pull head-ar in patients with increased vertical dimensions.ly a few studies have evaluated the results of a

adgear-activator combination; some discussed thertical effects accompanying this type of treatment.adgear-activator combination appliances producedorable effects in treated patients because the therapyvented the vertical relationships and the inclinationthe occlusal plane from increasing.11-17 The additiona headgear to functional appliance treatment appearsyield an outcome that is desirable in high-angle

tients.When bionator therapy alone was considered,

nge et al,18 Morris et al,19 and Illing et al20 reportednificant increases in lower anterior facial heightring treatment, an undesirable treatment effect in thise of patient. Faltin et al21 found a significant openingthe gonial angle in treated subjects compared withtreated controls.Most studies on the headgear-activator combination

d the bionator alone did not include untreated con-ls for the evaluation of treatment effectiveness,13-16d they did not provide specific information about thetreatment vertical skeletal patterns of the subjects.Our purpose in this clinical investigation was to

ke a detailed comparison between patients withreased vertical dimensions who underwent 2-phaseatment consisting of a first phase with a bionator andh-pull facebow combination followed by a second

ase of fixed appliances and a matched sample oftreated subjects with the same craniofacial morphol-y followed longitudinally.

TIENTS AND METHODS

The bionator high-pull facebow sample was derivedm a group of 40 consecutively treated patients fromprivate orthodontic practice of an author (T.W.G.).

eatment results were not a criterion for case selection.

To be included in this study, patients were required

meet the following criteria: (1) 2-phase treatmentounsisting of bionator and high-pull facebow wearlowed by preadjusted edgewise orthodontic treat-nt; (2) pretreatment Angle Class I or Class IIlocclusion; (3) 3 high-quality lateral cephalogramscentric occlusion with adequate visualization of

erence structures and no appreciable rotation of thead, obtained before phase 1 treatment (T1), beforease 2 treatment (T2), and after phase 2 treatment3); and (4) as derived from the cephalometric anal-is at T1, value for the mandibular plane relative to theankfort horizontal (MPA) of 25 or greater.

Twenty-four (13 girls, 11 boys) of the 40 subjectst the inclusionary criteria. The treated group com-sed 15 subjects with end-to-end molar relationship, 5th full Class II molar relationships, and 4 with Classolar relationships. The average ages were 9.2 yearsthe bionator and high-pull facebow group at T1,

.6 years at T2, and 14.7 years at T3.Cephalograms representing T1, T2, and T3 were

ected for 23 subjects (10 girls, 13 boys) withperdivergent facial patterns (MPA 25) from thehives of the University of Michigan Elementary

d Secondary School Growth Study. The controlup consisted of 15 subjects with end-to-end molar

ationships, 3 with full Class II molar relationships,d 5 with Class I molar relationships; this distribu-n in molar relationships was similar to the treated

ple. The subjects were similar to those of theated group in age at all observation times, durationobservation intervals, gender, and MPA. The

erage ages were 9.1 years at T1, 11.9 years at T2,d 14.7 years at T3.

eatment protocol

For phase 1, the bionator was constructed with a 45 mm posterior bite block that extended anteriorly to deciduous first molars (Fig 1). Ball clasps forention were included in the permanent maxillary firstlar region. Headgear tubes (.045 in) were embeddedthe level of the permanent first molars. A tongue

ield to prevent tongue thrust was included withpropriate air holes. A maxillary holding frame (Haw-

design) with adjustable loops also was incorporated.mandibular retrusion was part of the skeletal config-tion, up to a 4-mm advancement was incorporatedo the construction bite.The patients were instructed to wear the bionator

l time except for meals. High-pull headgear also wasrn for 10 to 14 hours a day (Fig 1). The anticipatedase 1 treatment time was 8 to 12 months on thisimen; however, level of cooperation and treatmenttcome sometimes extended the treatment time.In phase 2, the main purpose was to refine the

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American Journal of Orthodontics and Dentofacial OrthopedicsFebruary 2007

186 Freeman et alclusion; it consisted of complete banding/bondingth 0.018-in slot preadjusted fixed appliances. Class IIchanics such as elastics were used as necessary, andwearing of the high-pull facebow was continued.

phalometric analysis

The T1, T2, and T3 cephalograms were hand-ced on 0.003-in frosted acetate with a 2H sharp-ed lead drafting pencil. Films of a given seriesre traced at 1 sitting in the same manner by 1estigator (C.S.F.) and then verified for anatomical

ntour and landmark identification as well as trac-superimpositions by a second investigator

A.Mc.). Cephalometric software (Dentofacialnner, version 2.5, Toronto, Ontario, Canada) was

ed for a customized digitization regimen thatluded 78 landmarks and 4 fiducial markers. Thisgram allowed for analysis of cephalometric data

d superimposition of serial cephalograms accord-to the specific needs of this study.Lateral cephalograms for each patient at T1, T2,

d T3 were digitized, and 50 variables were gener-d for each film. The magnification factor of the

phalograms was standardized at 8%. A cephalo-tric and regional superimposition analysis con-ning measurements chosen from the analyses ofcNamara,22-24 Ricketts,25 and Steiner,26 and theits appraisal27 was performed on each cephalo-m analyzed in the study.The cranial base superimpositions were per-

med by aligning the basion-nasion line and regis-ing at the most posterosuperior aspect of the

Fig 1. Bionator witrygomaxillary fissure.22,25 In addition, the poste-r cranial outline was used to verify the superim-

Msition of cranial base structures. From this super-position, position changes of the maxilla andndible were measured. To superimpose the max-

a along the palatal plane, the superior and inferiorrfaces of the hard palate and internal structures of

maxilla superior to the incisors were used asdmarks. From this superimposition, the move-nts of the maxillary incisors and molars could beessed. The mandibular superimposition was per-med by using the mandibular canal posteriorly,

internal structures of the symphysis, and thesterior contour of the symphyseal outline. Thisperimposition allowed the measurement of move-nt of the mandibular teeth in the mandible.

rvical vertebral maturation analysis

The subjects in both groups were analyzed at T1,, and T3 with a reliable method for the assessment ofeletal maturity, the recently improved version of thervical vertebral maturation (CVM) method.28

atistical analysis

Means and standard deviations for age, duration ofatment, and all cephalometric measurements at T1,, and T3 for the bionator and high-pull facebow anduntreated control groups were calculated. Addition-

y, mean differences and standard deviations werelculated for the changes of T2-T1, T3-T2, and T3-T1

each group. The data were analyzed with statisticalftware (12.0, SPSS, Chicago, Ill). Statistical signifi-nce was tested at P .05, P .01, and P .001els. The method error was described previously by

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Freeman et al 187all variables to test the normality of the sample. Theults were not significant; this indicated normality oftribution for the examined parameters and recom-nded parametric statistics. Starting and final forms in2 groups were compared with independent sample

ests. Mean differences between the treatment andntrol groups at the different time intervals (T2-T1,-T2, and T3-T1) were compared by using indepen-nt sample t tests as well. The analysis of power of thedy indicated that, on the basis of number of subjectsthe examined groups and the standard deviations ofcephalometric variables, the level of clinical signif-

nce for treatment-induced differences with regard to

ble I. Comparison of starting forms at T1

phalometric measurements

Bionator facebow(n 24)

Mean SD

xillary skeletalNA angle () 81.2 4.1t A to nasion perp (mm) 0.5 2.8o-Pt A (mm) 82.8 4.5

ndibular skeletalNB angle () 75.1 3.8og to nasion perp (mm) 9.3 5.4o-Gn (mm) 100.9 5.1

xillary/mandibularNB angle () 6.1 2.6its (mm) 1.7 3.2axillary/mandibular difference (mm) 18.2 3.4

rtical skeletalPA () 30.1 4.5NS to Me (mm) LAFH 62.7 6.2r-Go (mm) 36.1 3.1-Me (mm) AFH 106.5 7.3o-Go (mm) 43.2 3.7onial angle () 131.7 6.0H to occlusal plane () 11.5 3.0H to palatal plane () 1.9 3.4

erdentalverbite (mm) 1.3 3.2verjet (mm) 5.8 1.9

nterincisal angle () 122.9 9.2olar relationship (mm) 0.3 1.5

xillary dentoalveolar1 to Pt A vert (mm) 4.1 1.9

ndibular dentoalveolar1 to Pt A Pog (mm) 1.6 1.71 to MP () 94.0 6.7t tissueL to E plane (mm) 0.8 2.2L to E plane (mm) 0.9 2.0asolabial angle () 112.9 12.5.05; NS, not significant.rtical dimension change was equal or greater than 2or 2 for a power of 0.80.

skmaSULTSalysis of starting forms

Descriptive statistics including means and standardviations for both groups at the start of treatment areen in Table I. Significant between-group differencesre noted for only 1 measurement. The treatmentup initially had greater mandibular ramus height

o-Go). The mean value of the MPA for both groupss about 30 (range, 25.6o to 39.1o).

alysis of T1-T2 changes

There were no significant differences in the

Controls (n 23)Difference SignificanceMean SD

80.4 3.8 0.8 NS0.3 2.9 0.8 NS80.6 4.7 2.2 NS

75.3 3.1 0.2 NS8.3 4.2 1.0 NS98.8 5.4 2.1 NS

5.1 1.9 1.0 NS0.9 2.4 0.8 NS

18.2 2.0 0.0 NS

29.4 3.0 0.7 NS60.5 4.3 2.2 NS35.2 3.2 0.9 NS

103.7 4.9 2.8 NS39.7 3.2 3.5 *

131.7 4.7 0.0 NS11.2 2.4 0.3 NS1.5 2.6 0.4 NS

0.9 3.2 0.4 NS5.0 1.9 0.8 NS

122.0 8.3 0.9 NS0.4 1.1 0.7 NS

4.0 1.6 0.1 NS

1.6 2.1 0.0 NS95.9 4.4 1.9 NS

1.3 2.2 0.5 NS0.1 1.9 0.8 NS

113.4 8.9 0.5 NSREAn

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188 Freeman et alT2 (Table II, Figs 2 and 3). Total mandibulargth (Co-Gn) showed a significantly larger in-ase in the treated group than in the control group2 mm). No other significant changes were found.om T1 to T2, the treated group had significantlyater increases in maxillary/mandibular differen-

l compared with the control group (2.2 mm). The

ble II. Comparison of changes during phase 1 treatmen



Mean SD







xillary dentoalveolar1 to Pt A vert (mm) 0.2 1.51 horizontal (mm) 0.1 1.71 vertical (mm) 1.8 1.66 horizontal (mm) 0.3 1.96 vertical (mm) 0.7 1.7

ndibular dentoalveolar1 to Pt A Pog (mm) 0.3 1.21 horizontal (mm) 0.0 1.31 vertical (mm) 2.8 2.06 horizontal (mm) 1.6 1.56 vertical (mm) 2.6 1.61 to MP () 3.4 4.6t tissueL to E plane (mm) 2.1 2.1L to E plane (mm) 1.0 1.8asolabial angle () 3.3 9.5.05; P .01; NS, not significant.anges in the Wits appraisal and the ANB anglere not significantly different between the 2 groups.

in(Significantly greater differences were found for therease in lower anterior facial height (ANS-Me) intreated group compared with the control group (1.3). Similarly, the increase in total anterior facial

ight (N-Me) was significantly greater in the treatedup when compared with the control group (2.1 mm).There was a significantly larger decrease in overjet

to T2)


0.4 1.4 0.1 NS0.4 1.2 0.1 NS

3.3 1.9 0.0 NS

0.2 1.2 0.7 NS0.2 1.8 1.0 NS5.4 2.5 2.2 *

0.5 0.9 0.8 NS0.0 1.6 0.8 NS2.1 1.7 2.2

0.3 1.4 0.6 NS2.2 1.7 1.3 *2.0 1.5 1.1 NS5.9 3.0 2.1 *2.4 2.3 1.7 NS1.6 2.1 0.3 NS1.6 3.0 0.1 NS1.0 1.7 0.9 NS

1.2 2.0 0.2 NS0.1 1.0 0.9 *

1.4 6.1 2.8 NS0.5 1.0 1.5

0.6 1.0 0.4 NS0.5 1.3 0.4 NS1.8 1.6 0.0 NS0.7 1.1 0.4 NS0.6 1.3 0.1 NS

0.5 1.1 0.2 NS0.6 1.1 0.6 NS1.9 1.1 0.9 NS1.5 1.1 0.1 NS1.6 1.3 1.0 *0.3 3.4 3.7

1.7 1.3 0.4 NS0.3 1.4 0.7 NS

3.8 6.7 0.5 NSincthemm

hegrothe treated group compared with the control group0.9 mm). Molar relationship had a greater increase in

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Freeman et al 189treated group than the untreated group (1.5 mm). Nonificant differences were found between the 2 groups

2. Composite tracings of treated group at T1ack), T2 (blue), and T3 (red ).

3. Composite tracings of control group at T1ack), T2 (blue), and T3 (red ).the T1 to T2 changes. A significantly larger increasethe vertical position of the mandibular first molar (L6

mm

tortical) was recorded in the treated group whenmpared with the untreated controls (1.0 mm). Anificant amount of lingual tipping of the mandibularisor occurred in the treated sample (3.7).No significant soft-tissue differences were found forT1-T2 changes between the 2 groups.

alysis of T2-T3 changes

There were significant differences between the 2ups for all maxillary skeletal measurements in theittal plane from T2 to T3 (Table III, Figs 2 and 3).th SNA angle and Point A to nasion perpendicular

owed significant decreases in the treated group whenmpared with the increases in the untreated controlsproximately 1.0 and 1 mm, respectively). Mid-ial length showed significantly smaller increases intreated group (1.9 mm). There were significant

ferences between the 2 groups for all mandibularasurements in the sagittal plane from T2 to T3. BothB angle and pogonion to nasion perpendicular hadnificant decreases in the treated group when com-red with the increases in the untreated controls1.4 and 2.7 mm, respectively). Total mandibulargth showed significantly smaller increases in theated group (3.9 mm). During phase 2 (T2 to T3),treated group had significantly smaller increases in

xillary/mandibular differential compared with thentrol group (2.0 mm). The changes in the Witspraisal and the ANB angle were not significantlyferent in the 2 groups.A significant increase in MPA was noted in the

ated group with respect to the decrease seen in thentrols (1.3). Significantly smaller increases werend for both ramus height (Ar-Go) and total anteriorial height (N-Me) in the treated group comparedth the control group (1.3 and 2.7 mm, respec-ely). A significant increase in inclination of Frank-t horizontal to occlusal plane occurred in the treatedup compared with the decrease in the controls.The only dental measurement with a significant

ference between the treated and the control groupss interincisal angle, with a significant decrease in theated group compared with the controls (8.3). Nonificant differences were found between the 2 groupsthe T2 to T3 changes. A significant increase in theittal position of the mandibular incisor (L1 to Pt A

g and L1 horizontal) was recorded in the treatedup when compared with the decreases in the un-

ated controls (1.8 and 1.3 mm, respectively). Anificantly smaller extrusion of the mandibular inci-

r (L1 vertical) occurred in the treated sample (1.1

). A significant flaring of the mandibular incisor (L1

MP) was observed in the treated group (7.2).

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190 Freeman et alA significantly smaller decrease in the position oflower lip to the esthetic plane was seen in the

ated group vs the controls (2.2 mm).alysis of T1-T3 changes

The overall treatment produced a significantlyger decrease in Point A to nasion perpendicular and

ble III. Comparison of changes during phase 2 treatme



Mean SD








ndibular dentoalveolar1 to Pt A Pog (mm) 1.6 1.31 horizontal (mm) 1.0 1.51 vertical (mm) 1.3 1.36 horizontal (mm) 1.3 1.46 vertical (mm) 1.7 1.41 to MP () 5.2 5.1t tissueL to E plane (mm) 1.4 1.8L to E plane (mm) 0.2 1.7asolabial angle () 0.8 9.6.05; P .01; P .001; NS, not significant.significantly smaller increase in midfacial lengthmpared with the controls (1.1 mm and 1.9 mm,

twpectively) (Table IV, Figs 2 and 3). Pogonion tosion perpendicular had significantly smaller in-ases in the treated group than in the untreated

ntrols (1.7 mm). No other significant differencesre found between the 2 groups. During the treatmentriod (T1 to T3), no significant differences were noted

any maxillomandibular sagittal measurement be-

to T3)


0.3 1.4 0.9 *0.1 1.3 1.0 3.5 1.8 1.9

1.2 1.0 1.4 1.7 1.8 2.7 7.4 3.2 3.9

0.9 1.3 0.5 NS0.4 1.7 0.2 NS

3.9 2.8 2.0

0.8 1.4 1.3 *4.0 2.4 1.2 NS4.3 2.8 1.3 7.3 3.2 2.7 4.1 2.7 1.2 NS2.4 2.0 1.4 NS2.1 2.5 2.7 0.9 2.0 0.9 NS

0.2 1.8 0.7 NS0.9 1.1 0.6 NS

3.7 6.9 8.3 0.1 1.4 0.6 NS

0.2 1.1 0.1 NS0.3 1.3 0.1 NS

1.4 1.0 0.5 NS1.8 1.8 0.4 NS1.2 1.6 0.1 NS

0.2 1.2 1.8 0.3 1.4 1.3

2.4 1.5 1.1 *1.1 1.3 0.2 NS2.6 1.7 0.9 NS2.0 4.3 7.2

2.2 3.0 0.8 NS2.4 1.9 2.2

0.2 14.6 1.0 NSres

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Freeman et al 191up with respect to the decrease in the controls (1.9).nificantly smaller decreases were found for both

nial angle and inclination of the occlusal plane to theankfort horizontal in the treated group compared with

controls during the observation period (1.7 and, respectively).The only dental measurement that showed a signif-

ble IV. Comparison of changes during overall treatmen



Mean SD








ndibular dentoalveolar1 to Pt A Pog (mm) 1.8 1.61 horizontal (mm) 1.0 1.71 vertical (mm) 4.1 2.16 horizontal (mm) 2.9 1.56 vertical (mm) 4.3 1.41 to MP () 1.9 6.9t tissueL to E plane (mm) 3.5 2.2L to E plane (mm) 1.2 2.0asolabial angle () 2.6 9.9.05; P .01; NS, not significant.nt difference between the treated and the controlups was overjet, with a significantly greater de-

inc(3.ase in the treated group than in the controls (1.5). No significant differences were found between2 groups for the T1 to T3 changes. A significantly

ater increase in the sagittal position of the mandib-r incisor (L1 to Pt A Pog vertical) was recorded intreated group when compared with the untreated

ntrols (1.5 mm). Significant flaring of the mandibular

to T3)


0.1 2.0 0.8 NS0.3 1.7 1.1 *

6.8 3.1 1.9 *

1.4 1.4 0.7 NS1.9 2.1 1.7 *

12.8 4.2 1.8 NS

1.5 1.4 0.1 NS0.4 2.4 0.6 NS

6.0 3.1 0.1 NS

1.1 1.9 1.9 6.2 2.8 0.0 NS6.3 2.7 1.2 NS

13.2 4.8 0.6 NS6.5 2.4 0.5 NS4.0 3.0 1.7 *3.6 3.0 2.5 1.8 2.3 0.2 NS

1.0 2.7 0.9 NS0.9 1.4 1.5

5.2 8.4 5.6 NS0.5 1.3 1.1 NS

0.5 1.5 0.6 NS0.2 1.6 0.4 NS3.2 1.7 0.5 NS2.5 1.6 0.1 NS1.8 1.8 0.1 NS

0.3 1.7 1.5 0.3 1.9 0.7 NS4.3 2.2 0.2 NS2.6 1.5 0.3 NS4.2 2.4 0.1 NS1.7 5.1 3.6 *

3.9 2.7 0.4 NS2.8 1.9 1.6 *

4.0 13.9 1.4 NScre

mm

thegreulathecoisor (L1 to MP) was observed in the treated group6).

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192 Freeman et alA significantly smaller decrease in the position oflower lip to the esthetic plane was found in the

ated group vs the controls during the observationriod (1.6 mm).alysis of final forms

Significant between-group differences wereted for a few measurements (Table V). The treatedup had a significantly larger MPA value (2.5)n did the controls; posterior facial height (Co-Go)

owed a greater value in the treated group (2.9 mm)the controls, and the angle between Frankfort

rizontal and the occlusal plane opened 2.8. Over-was smaller in the final form for the treated

ble V. Comparison of final facial forms at T3



Mean SD







xillary dentoalveolar1 to Pt A vert (mm) 3.9 2.3

ndibular dentoalveolar1 to Pt A Pog (mm) 3.4 1.71 to MP () 95.9 7.6t tissueL to E plane (mm) 4.3 1.9L to E plane (mm) 0.3 3.0asolabial angle () 115.4 12.4.05; P .01; NS, not significant.up than in the control group (0.8 mm). Thendibular incisor was in a more labial position in

growhtreated group (L1 to Pt A-Pog) with respect to thentrols (1.5 mm); this was associated with a lessrusive position of the lower lip to the E-plane3 mm).alysis of skeletal maturation

The analysis of CVM at T1 showed that the 2ups were nearly identical at the start. At T1, 88% of the

atment group were prepubertal (cervical stage [CS]1d CS2) and 12% of the patients were pubertal (CS3);% of the control subjects were prepubertal and 17% of subjects were pubertal.28 Therefore, the 2 groups werell matched at T1 as to skeletal maturation.The distribution of the maturational stages in the 2


80.4 3.7 0.2 NS0.6 2.9 0.3 NS87.3 5.3 0.4 NS

76.7 3.4 0.9 NS6.4 4.7 2.7 NS111.5 7.1 0.5 NS

3.7 1.9 0.7 NS0.5 3.5 0.2 NS

24.2 3.7 0.1 NS

28.3 3.8 2.5 *66.7 6.1 2.2 NS41.5 4.2 0.3 NS

118.9 7.8 2.4 NS46.3 3.7 2.9 *

127.7 5.3 1.6 NS7.6 2.9 2.8 0.3 3.1 0.2 NS

1.9 2.1 0.6 NS4.0 1.4 0.8 *

127.1 9.8 4.6 NS0.9 1.1 0.3 NS

4.4 2.1 0.5 NS

1.9 2.4 1.5 *94.2 6.6 1.7 NS

5.2 2.9 0.9 NS2.6 1.7 2.3 117.3 16.8 1.9 NStheco

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83theweups was different at T2. The percentage of subjectso went through their pubertal growth spurt during T1

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Freeman et al 193T2 interval in the treated group (58%) was more thanice that of the subjects in the control group (26%). At, all subjects in both groups were at postpubertalges of skeletal maturation. This means that only 42%subjects in the treated group and 74% of the controlup went through their pubertal peak during the T2 tointerval.

SCUSSION

The lack of literature concerning nonsurgical treat-nt of the vertical dimension is in sharp contrast withcritical effect of vertical disharmonies on treatment

tcomes in dentofacial orthopedics. One proposedatment modality is a 2-phase protocol consisting of anator combined with a high-pull facebow, followedfixed appliances in growing subjects.To date, only 2 short-term investigations used

treated controls for the evaluation of the effective-ss of a protocol similar to that described above.12,17

activator as a fundamental part of the protocolplies that both the treated and the control groupsscribed in the literature include patients with Class IIntoskeletal disharmonies. Stckli and Teuscher12 re-rted favorable dentoalveolar effects on the maxillaociated with an anterior position of the mandible.ta pertaining to the effects of this treatment protocolvertical skeletal relationships were mentioned onlyefly as an aside in the discussion of their investiga-n. Similarly, treatment effects in the vertical dimen-n were mentioned in passing in the more recentdy by Sari et al.17 They compared the effects of an

tivator-headgear combination with a removable Jas-r jumper appliance-headgear combination and with

untreated control group. For the most part, theynfirmed the results of Stckli and Teuscher.12 Theirtcomes in terms of vertical skeletal changes wereher insignificant or in some cases even unfavorable.our knowledge, no studies have analyzed the effi-

cy of the bionator-facebow treatment protocol at asttreatment observation, including a second phase ofed appliances.We examined the treatment effects of the bionator

d high-pull facebow followed by fixed orthodonticpliances in growing subjects with mild-to-severeperdivergent facial patterns (greater than averagelue for MPA) with Class I or Class II malocclusions.ase 1 treatment produced a significant increase inal mandibular length (Co-Gn) of about 2 mm moren in the controls, a modification that is favorable in

ass II patients. During phase 2 treatment, however,opposite was observed. Total mandibular lengthreased 4 mm less in the treated subjects than in thentrols. After the study, the increments in total man-

resular length in the bionator and high-pull facebowd the control groups were not distinguishable statis-ally.There are 2 possible explanations for this observa-

n. The first is that the treated patients simply weresturing their mandibles forward after treatment. Thephalometric analysis included a visual inspection of

relationship of the posterior border of the ramus toanterior border of the second cervical vertebrae in

ial films. No mandibular posturing was evident iny patient or subject.

The second interpretation can be derived by takingo account differences in skeletal maturation between

patients and the controls during the 2 phases ofatment with the CVM method.28 The percentage ofbjects who went through their pubertal growth spurtsring the T1-T2 interval in the treated group (58%)s more than twice that of the subjects in the controlup (26%). At T3, all subjects in both groups were at

stpubertal stages of skeletal maturation. This meanst only 42% of the subjects in the treated group and% of the control group went through the pubertalaks during the T2 to T3 interval. The differences ining of the pubertal skeletal growth spurt could

count for the differential amount of supplementaryndibular growth between the 2 groups during the 2ases.As to the changes seen in the maxilla, there seems

be a significant amount of restriction in maxillaryittal growth as a consequence of the overall treat-nt protocol (about 2 mm along Co-Pt A). Interest-ly, this result was observed during the second phasefixed appliances, not during the active orthopedicdification attempted during phase 1 treatment. This

servation can be explained by the Class II mechanicsch as elastics and the continued use of the high-pullebow during fixed appliance therapy.A unique feature of our investigation was the focusthe analysis of the changes in vertical skeletal

ationships in treated and untreated hyperdivergentbjects. During the overall observation period, theated group had more vertical growthie, an increaseMPA, rather than a decrease of the same angle intreated vertical growers. The net difference for MPAs about 2. A similar behavior occurred in bothnial angle and inclination of the occlusal plane toankfort horizontal. Both measurements had smallercreases (2-2.5) when compared with the controls.e greatest increase in the vertical dimension tookce during phase 2 treatment, when a significantrease in MPA was noted in the treated group with

pect to the decrease seen in the controls (1.3).There were significant increases in lower and total

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194 Freeman et alterior facial heights during phase 1 in the treatedup; these findings were reversed during phase 2.ese reversals can be explained again by the differ-ces in timing of the pubertal growth spurt between

groups when describing the mandibular changesn in this study. Moreover, it is well known that the

e of a functional appliance to posture the mandibleward entails opening the bite as a consequence.17-21It is interesting but not surprising that an appliance

ting through the maxilla such as a bionator combinedth high-pull headgear did not affect the inclination of

palatal plane relative to the Frankfort horizontal.rmaut et al11 studied the dental and skeletal effectsthe headgear-activator and found that an orthopedicect on the palatal plane could not be established.is lack of effect was recorded at both observationriods.

When analyzing the dentoalveolar and soft-tissueasurements, we found significant posttreatment dif-ences represented primarily by the inclination of thendibular incisor to the mandibular plane. During T1T2, significant lingual tipping of the mandibularisor to the mandibular plane was observed. Thisding was unusual; proclination, not retroclination, ofmandibular incisors (when capping of these teeth is

t used) is common with bionator therapy.21 However,ring T2 to T3, a significant proclination of thendibular incisor was reflected in the position of theer lip to the esthetic plane; this expressed a signif-

nt tendency for protrusion when compared with thentrols after the observation period.

Other statistically significant differences betweenated and untreated subjects were noted from thehase treatment. The absolute amount of between-up difference in change, however, did not reach

nical significance. Due to the power of the study, at between-group difference of 2 mm or 2 must bensidered the threshold for clinical significance. Fortance, favorable changes such as an improvement ofmm in overjet, although statistically significant andorted in the tables, were not considered clinicallynificant and were not included in this discussion.The between-group comparisons on both the initial

d final forms were intended to test the hypothesis thathase treatment with a bionator and high-pull head-

ar followed by fixed appliances would induce nor-lization of the hyperdivergent facial pattern in theated subjects. This comparison was legitimatized bysimilarity of the initial forms. The analysis of final

ms provided no evidence of normalization of thetial problems in the vertical dimension. On the

ntrary, the final forms of the treated subjects demon-ated significantly more severe skeletal disharmoniesthe vertical plane than the untreated subjects, at bothstatistical and clinical levels. At the end of the

servation period, the treated subjects showed a 2.5ater opening of the MPA than did the controls.Our results agree with those of Sari et al,17 whoorted worsening of the vertical skeletal relationships

subjects treated with a similar protocol. Based on thistcome and the limited information in the literature,use of a bionator combined with high-pull headgear

es not appear to be an effective treatment option inwing patients with increased vertical dimensions offace. Even the modifications along the sagittal plane

re minimal, especially when considering the burdentreatment. These modifications were representedstly by restriction in maxillary growth that actually

curred during the fixed orthodontic appliance phased were most likely the result of Class II mechanicsch as elastics or continued use of the high-pullebow.

NCLUSIONS

This study was designed to evaluate the clinicalpact of the first phase of bionator and high-pulladgear treatment followed by a second phase of fixedpliances in subjects with dental and skeletal verticalcesses to normalize their vertical dimensions duringwth. The findings indicated that the bionator andh-pull headgear worsened the hyperdivergent facial

ttern at a clinically significant level, as shown by theal facial forms. The treated group had a significantlyger MPA value than did the controls (2.5) and ager inclination of the Frankfort horizontal to theclusal plane (2.8).

The significant changes in jaw dimensions andationships seen during phases 1 and 2 can beplained by between-group differences in timing of

pubertal growth spurt rather than by actual treat-nt effects. Our findings suggest that treatment withnator and high-pull headgear is not recommendedgrowing patients with hyperdivergent facial patternsen the goal is to decrease the vertical dimensions offace.

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17. Sari Z, Goyenc Y, Doruk C, Usumez S. Comparative evalu-ation of a new removable Jasper jumper functional appliancevs an activator-headgear combination. Angle Orthod 2003;73:286-93.

18. Lange DW, Kalra V, Broadbent BH Jr, Powers M, Nelson S.Changes in soft tissue profile following treatment with thebionator. Angle Orthod 1995;65:423-30.

19. Morris DO, Illing HM, Lee RT. A prospective evaluation ofBass, bionator and twin block appliances. Part IIthe softtissues. Eur J Orthod 1998;20:663-84.

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Treatment effects of the bionator and high-pull facebow combination followed by fixed appliances in patients with increased vertical dimensionsPATIENTS AND METHODSTreatment protocolCephalometric analysisCervical vertebral maturation analysisStatistical analysis

RESULTSAnalysis of starting formsAnalysis of T1-T2 changesAnalysis of T2-T3 changesAnalysis of T1-T3 changesAnalysis of final formsAnalysis of skeletal maturation

DISCUSSIONCONCLUSIONSREFERENCES

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