comparison of 2 comprehensive class ii treatment protocols bonded herbst and headgear pdf

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Comparison of 2 comprehensive Class IItreatment protocols including the bonded Herbst

and headgear appliances: A double-blind studyof consecutively treated patients at puberty

Tiziano Baccetti,a Lorenzo Franchi,a and Franka Stahlb

Florence, Italy, Ann Arbor, Mich, and Rostock, Germany

Introduction: The aim of this clinical trial was to compare the effects of 2 protocols for single-phase compre-

hensive treatment of Class II Division 1 malocclusion (bonded Herbst followed by fixed appliances [BH 1 FA]

vs headgear followed by fixed appliances and Class II elastics [HG 1 FA]) at the pubertal growth spurt.

Methods: Fifty-six Class II patients were enrolled in the trial and allocated by personal choice to 2 practices,

where they underwent 1 of 2 treatment protocols (28 patients were treated consecutively with BH1 FA, and 28

patients were treated consecutively with HG 1 FA). All patients started treatment at puberty (cervical stage

[CS] 3 or CS 4) and completed treatment after puberty (CS 5 or CS 6). Lateral cephalograms were taken before

therapy and 6 months after the end of comprehensive therapy, with an average interval of 28 months. Longi-

tudinal observations of a matched group of 28 subjects with untreated Class II malocclusions were compared

with the 2 treated groups. Analysis of variance (ANOVA) with post-hoc tests was used for statistical compar-

isons. Discriminant analysis was applied to identify preferential candidates for the BH 1 FA protocol on the

basis of profile changes (advancement of the soft tissues of the chin). Results: The success rate (full occlusal

correction of the malocclusion after treatment) was 92.8% in both treatment groups. The BH 1 FA group

showed a significant increase in mandibular protrusion. The increase in effective mandibular length (Co-Gn)

was significantly greater in both treatment groups when compared with natural growth changes in the Class

II controls. Significantly greater improvement in sagittal maxillomandibular relationships was found in the BH

1 FA group. Retrusion of maxillary incisors and mesial movement of mandibular molars were significant in the

HG 1 FA group. The BH 1 FA group showed significantly greater forward movements of soft-tissue B-point

and pogonion compared with both the HG1 FA and the control groups. Two pretreatment variables were sig-nificant (F 5 4.48; P \0.01) in predicting the posttreatment amount of mandibular soft-tissue improvement in

the BH 1 FA group: Co-Go-Me and pogonion to nasion perpendicular. Conclusions: Class II treatment with

either protocol during the pubertal growth spurt induces significant favorable dentoskeletal and occlusal

changes. Functional jaw orthopedics had a greater favorable impact on the advancement of the chin. The clin-

ical indications for the preferential use of the Herbst appliance at puberty are a small mandibular angle and

mandibular retrusion before treatment. When treated with the BH 1 FA protocol, these Class II patients

have the greatest probability of achieving significant improvement in the profile by advancement of the soft

tissues of the chin. (Am J Orthod Dentofacial Orthop 2009;135:698.e1-698.e10)

C

lass II Division 1 malocclusion affects many

orthodontic patients (about a third of all subjects seeking orthodontic treatment) with vari-

able combinations of dental and skeletal factors

contributing to the disharmony.1 Among the various

treatment strategies for Class II treatment, 2 modalities

are widely used for 1-phase comprehensive therapy of

the malocclusion in the adolescent period. One proto-

col is headgear associated with a fixed appliance

(HG 1 FA) with the adjunct of Class II elastics.2-4

An alternative approach is functional jaw orthopedics

immediately followed by FAs to refine the occlusion.

Various functional appliances have been proposed for

a Assistant professor, Department of Orthodontics, University of Florence,

Florence, Italy; Thomas M. Graber Visiting Scholar, Department of Orthodon-

tics and Pediatric Dentistry, School of Dentistry, University of Michigan, AnnArbor.b Assistant professor, Department of Orthodontics, University of Rostock,

Rostock, Germany.

The authors report no commercial, proprietary, or financial interest in the prod-

ucts or companies described in this article.

Supported in part by research funds of the T. M. Graber Scholarship, University

of Michigan; the Max Kade Foundation, and the German Orthodontic Society,

Rostock, Germany.

Reprint requests to: Tiziano Baccetti, Dipartimento di Odontostomatologia,

Università degli Studi di Firenze, Via del Ponte di Mezzo, 46-48, 50127, Fire-

nze, Italy; e-mail, [email protected].

Submitted, December 2007; revised and accepted, March 2008.

0889-5406/$36.00

Copyright 2009 by the American Association of Orthodontists.

doi:10.1016/j.ajodo.2008.03.015

698.e1

mailto:[email protected]:[email protected]


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single-phase orthopedic approach to Class II dishar-

mony.5-9

A series of both retrospective and prospective trials

have compared the dentoskeletal effects of headgear

therapy with functional jaw orthopedics. They all agreethat there is a slightly greater restriction in maxillary

growth in the HG samples, whereas functional jaw

orthopedics induces a slightly greater mandibular

growth or advancement.10-13 Some of these studies

were short term and did not consider any time interval

after use of the appliance, and some did not include

the phase of FAs in the overall treatment protocol. Fur-

thermore, these investigations either did not report the

skeletal maturity of patients or state that therapy was

performed at a prepubertal stage of skeletal develop-

ment. In this regard, evidence has been gathered that

functional appliances induce the greatest effects on

skeletal facial structures at the pubertal growth spurt

or slightly after it.14-19 A similar timing of intervention

was shown to produce the most favorable treatment out-

comes also for HG therapy.20

The aim of this investigation was to compare the

therapeutic dental, skeletal, and soft-tissue effects of 2

protocols for 1-phase comprehensive treatment of Class

II Division 1 malocclusion (bonded Herbst followed by

FA [BH 1 FA] vs HG 1 FA and Class II elastics) at the

pubertal growth spurt in a clinical trial that included also

a matched sample of untreated Class II controls.

MATERIAL AND METHODS

A sample of 56 subjects with Class II Division 1

malocclusion (overjet .5 mm, full Class II molar

relationship, and ANB angle .4) was treated at 2 pri-

vate practices, each performing a specific treatment

protocol for Class II Division 1 patients. This investiga-

tion was based on data collected during a series of pro-

lective clinical trials on the dentoskeletal modifications

produced in patients with Class II disharmony treated

with different orthodontic or orthopedic approaches.

Since the 2 practioners were in the same geographic

area (Ann Arbor, Mich), the cost of therapy was similar,and the entry diagnostic criteria were identical. The

conditions for patient enrollment, based on personal

choice, could be assimilated to a random allocation

of patients. Each practitioner enrolled 28 patients

consecutively for treatment with his respective specific

1-phase orthodontic protocol. One practitioner per-

formed HG1FA therapy with Class II elastics, and

the other treated 28 patients with the BH 1 FA proto-

col. No extractions were part of either protocol. To con-

trol for proficiency bias, the 2 practitioners were well

trained and experienced in their respective treatment

regimens, and they did not take part in analysis of the

collected data.

All 56 patients started therapy at peak velocity in

craniofacial growth as assessed by the cervical vertebral

maturation method

19

(cervical stage [CS] 3 or CS 4 atthe first observation). The similarity in treatment timing

between the 2 groups and the identical diagnostic crite-

ria in both groups before treatment limited the suscepti-

bility bias in the study. Furthermore, as has been

demonstrated extensively, a combination of maxillary

and mandibular modifications contributes to the final

Class II correction with either protocol.4-6,13,21,22

Thus, no distinction was made between Class II patients

with maxillary protrusion vs mandibular retrusion

before treatment.

Lateral cephalograms before (T1) and after (T2)

treatment were analyzed, with T1 corresponding to

the start of either therapy, and T2 corresponding to 6

months after the phase with fixed appliances. During

these 6 months after treatment, the patients wore reten-tion plates at night. Mean ages at T1 and T2, mean

duration of the T1-to-T2 intervals, and stages in cervical

vertebral maturation at T1 and T2 are shown in Table I.

All patients were eitherat CS 5 or CS 6 atT2—a postpu-

bertal stage of skeletal maturation. It was demonstrated

that the actual amount of growth of the maxillary bases

in a Class II subject after CS 5 or CS 6 is minimal, and

that differences in the amount of craniofacial growth

between Class II and Class I subjects after these stages

is insignificant.23

The practitioners who performed the 2 treatment

protocols did not know that those patients would be

part of a clinical trial on the differential effects of the

2 protocols in Class II malocclusion. Similarly, the

examiners who analyzed their lateral cephalograms at

T1 and T2 were blind as to the origin of the films and

to the patient groups (double-blind design of the study).

The T2 observations were collected and analyzed

regardless of the treatment outcomes in terms of correc-

tion of Class II malocclusion in the patients. This assis-

ted in further reducing potential selection biases of the

study.To appraise the effectiveness of Class II treatment at

puberty beyond the comparative evaluation of the 2

treatment protocols, a historical cohort of longitudinal

observations on untreated Class II subjects was included

in the study. A sample of 28 subjects was selected from

the University of Michigan Growth Study with the same

dentoskeletal characteristics and skeletal maturational

levels at T1 as the 2 treatment samples. The duration

of the T1-to-T2 observation interval in the control group

matched the T1-to-T2 intervals of the 2 treatment

groups (Table I). The male-to-female ratio was 1:1 in

698.e2 Baccetti, Franchi, and Stahl American Journal of Orthodontics and Dentofacial Orthopedics June 2009


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all groups to eliminate the effects of sexual dimorphism

on craniofacial sizes and changes.

Treatment protocols

All 28 patients of the HG 1 FA sample underwent

the same protocol of 1-phase, nonextraction, Class II

therapy. After an initial period with brackets at the max-

illary arch to derotate the molars (when needed), cervi-

cal-pull HG was worn on average 14 hours a day for 12

months with FA therapy (.018-in slot). In patients with

high-angle vertical relationships (5 had a Frankfort hor-

izontal to mandibular plane angle equal to or greater

than 30)2, the pull of the HG was more vertical. The

HG was followed by Class II elastics (either 5/16 in, 4

oz, or 5/16 in, 6 oz). Class II elastics were worn for 6

to 10 months, and the patients were asked to wear

them full time. A retention period of 6 months followed

fixed appliance therapy. During this period, the patients

wore retention plates at night.The BH appliance for all patients was fabricated

according to the principles of McNamara et al.21 The

BH appliance had occlusal coverage from the canines

to the first molars in the maxillary arch and full coverage

in the mandibular arch. About 75% of the maxillary

splints were removable, with the remainder bonded,

whereas the mandibular splint always was removable.

In about half of the appliances, a midpalatal expansion

screw was incorporated into the appliance and activated

a quarter turn once a week until the appropriate expan-

sion of the maxilla was achieved. The patients were

instructed to wear the appliance at all times except dur-ing eating, brushing, and flossing. The mandible was

brought forward 3 to 4 mm initially and then further

advanced in 2- to 3-mm increments at the clinician’s

discretion until the buccal segments were in a Class I

relationship or slightly forward of Class I. When the

mandible could no longer be manipulated posterior to

the desired interocclusal relation on removal of the

acrylic-splint Herbst, the appliance was worn full time

approximately 3 months longer; after that, most patients

wore the appliance part time until they were ready for

full-banded orthodontic therapy. Total treatment time

with the BH was 11 months, followed by FA therapy

(.018-in slot). No Class II elastics were worn during

this phase. In the HA 1 FA protocol, a retention period

of 6 months followed FA therapy, when the patients

wore retention plates at night.

Cephalometric analysis

A customized digitization regimen and analysis pro-

vided by cephalometric software (version 3.0, Viewbox,

dHAL Software, Kifissia, Greece) was used for all ceph-

alograms in this study. The cephalometric analysis

required digitization of 77 landmarks and 4 fiducial

markers. The customized cephalometric analysis con-

taining measurements f rom the analyses of Steiner,24

Jacobson,25 Ricketts,26 and McNamara27 was used,

generating 33 variables—11 angular and 22 linear—

for each tracing.

All sets of cephalograms were traced at the same

time. A preliminary tracing was made for each film inthe series, with particular attention paid to tracing the

outlines of the maxilla and the mandible, including

the mandibular condyle. Then each set of consecutive

films was checked thoroughly, beginning with the sec-

ond and third films in the series. Fiducial markers

were placed in the maxilla and the mandible on the third

tracing and transferred to the second tracing in each sub-

ject’s cephalometric series, based on superimposition of

internal maxillary or mandibular structures. The loca-

tions of the fiducial markers then were transferred to

the first and the fourth through sixth films similarly.

The maxillae were superimposed along the palatalplane by registering on the bony internal details of the

maxilla superior to the incisors and the superior and in-

ferior surfaces of the hard palate. Fiducial markers were

placed in the anterior and posterior parts of the maxilla

along the palatal plane. This superimposition describes

the movement of the maxillary dentition relative to the

maxilla.

The mandibles were superimposed posteriorly on

the outline of the mandibular canal. Anteriorly, they

were superimposed on the anterior contour of the chin

and the bony structures of the symphysis. A fiducial

Table I. Demographics for the treated subjects (after dropouts) and the historical untreated Class II group

Age (y) at T1 (CS 3 or CS 4) Age (y) at T2 (CS 5 or CS 6) T1-T2 interval (y)

n Mean SD Mean SD Mean SD

HG 1 FA 28 (14 F, 14 M) 13.0 1.2 15.7 1.1 2.8 0.6BH 1 FA 28 (14 F, 14 M) 13.0 0.8 15.7 1.0 2.7 0.7

Controls 28 (14 F, 14 M) 12.9 1.3 15.6 1.4 2.7 0.9

F , Female; M, male.

American Journal of Orthodontics and Dentofacial Orthopedics Baccetti, Franchi, and Stahl 698.e3Volume 135, Number 6


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marker was placed in the center of the symphysis and

another in the body of the mandible near the gonial an-

gle. This superimposition facilitated measuring the

movement of the mandibular dentition relative to the

mandible.For the analysis of the soft-tissue profile changes,

the method of Arnett et al28 was used with modifications.

The system consisted of measurements with a reference

vertical line (VL) perpendicular to the Frankfort plane,

and it was traced through subnasale. This line was a mod-

ification of the true vertical line of Arnett et al.28 Profile

points measured to the VL were soft-tissue A-point (A0),

soft-tissue B-point (B0), and soft-tissue pogonion (Pg0).

Cephalograms were traced by 1 investigator (L.F.)

and verified for landmark location, anatomic contours,

and tracing superimpositions by another (T.B.). Any

disagreements were resolved by retracing the landmark

or the structure to the satisfaction of both observers. A

total of 45 lateral cephalograms randomly chosen

from all observations were retraced and redigitized tocalculate method error with Dahlberg’s formula.29 The

error for linear measurements ranged from 0.3 mm

(overjet) to 0.7 mm (Pg to nasion perpendicular); the

error for angular measurements varied from 0.3

(ANB) to 1.5 (interincisal angle).

The assessment of the stages in cervical vertebral

maturation on lateral cephalograms for each subject

was performed by one investigator (T.B.) and verified

by a second (L.F.).19 Disagreements were resolved to

the satisfaction of both observers.The magnification values of the data sets for the

treated patients and the untreated subjects were differ-

ent; the lateral cephalograms of the treated subjects

had 11% enlargement, and those from the control group

had magnifications of either 12.9% or those from the

control group had magnifications of either 12.9% or

4%. The lateral cephalograms of all subjects were cor-

rected to an 8% enlargement factor.

The size of the samples for the study was estimated

before the clinical portion of the trial on the basis of the

standard deviations of the changes in maxillary and

mandibular structures from a previous study.6

The cal-culated power of the study exceeded 0.90 at a 5 0.05

with a sample size of 28.

Statistical analysis

Descriptive statistics of craniofacial measurements

in all treated and untreated Class II subjects at T1 and

T2 were calculated, as well as the between-stage

changes. The Kolmogorov-Smirnov test showed nor-

mality of distribution for the measurements we used.

Therefore, parametric statistics with analysis of vari-

ance (ANOVA) with the Tukey post-hoc test were

used (version 12.0, SPSS, Chicago, Ill). The following

comparisons were made for the dentoskeletal and soft-

tissue variables: HG 1 FA group vs BH 1 FA group

vs untreated Class II group on the values at T1 (startingforms), and HG 1 FA group vs BH 1 FA group vs

untreated Class II group on the values of the T1-to-T2

changes (treatment effects).

Since the success of therapy was not a factor for

inclusion of treated patients in the study and because,

in the 2 treatment groups, patients were treated consec-

utively by the same operator with a standardized proto-

col, an analysis of treatment-induced ‘‘successful

correction’’ of initial dentoskeletal Class II discrepancy

could be carried out in these 2 groups. Success or unsuc-

cess (excessive overjet or full-cusp or half-cusp Class II

molar relationship) at T2 was assessed in the 2 treated

groups.

A further analysis of the data included also discrim-

inant analysis to possibly identify pretreatment cephalo-

metric variables that could account for final significant

differences in soft-tissue profile as measured at the

chin (D Pg0-VL) in the BH 1 FA sample. The final

goal of this analysis was to isolate characteristics of

optimal candidates for this type of Class II treatment

at puberty.

RESULTS

The success rate was 92.8% (26 of the 28 treatedpatients) in both the HG 1 FA BH 1 FA groups. The

4 unsuccessful patients had excessive overjet and half-

cusp Class II molar relationships at T2.

The statistical comparison on starting forms for

hard-tissue measurements between the 2 treatment

groups and the untreated control group showed no signif-

icant differences except overjet and molar relationship,

which were actually significantly greater in both treat-

ment groups than in the untreated controls (Table II).

Furthermore, there were no significant differences for

any soft-tissue measurements at T1.

Results of the statistical comparisons of the T2-to-T1 changes between the HG 1 FA patients vs the

Class II untreated controls, between the BH 1 FA

patients vs the Class II untreated subjects, and between

the HG 1 FA and BH 1 FA patients are shown in

Table III.

The statistical comparison of the T2-to-T1 changes

in the BH 1FA group vs the untreated group showed

a significantly more retruded position of the maxilla in

relation to nasion perpendicular (Pt A-nasion perp).

There were significant differences between the treat-

ment groups with regard to mandibular skeletal



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changes, indicating a significant increase in mandibular

protrusion (SNB and Pg-nasion perp) in the BH 1 FAgroup. This group had a significant increase in

Pg-nasion perp compared with the untreated controlsas well. The increase in effective mandibular length

(Co-Gn) was significantly greater in both treatment

groups when compared with the natural growth changes

in the Class II controls. There were no significant differ-

ences in changes in mandibular length between the 2

treatment groups. Comparison of changes in intermaxil-

lary relationships showed significantly greater de-

creases in ANB angle and the Wits appraisal, and

a significant increase in the maxillomandibular differen-

tial in the BH 1 FA treatment group compared with

both the untreated Class II and the HG 1 FA groups.With regard to changes in vertical skeletal relation-

ships, the increase in lower anterior facial height was

significantly greater in both treatment groups when

compared with the untreated controls. The change in an-

gulation of the palatal plane relative to the Frankfort

horizontal was significantly different between the 2

treatment groups, showing a slight opening of this angle

in the HG 1 FA group.

The interdental changes were significantly greater in

the 2 treatment groups compared with the untreated

controls. Both treatment groups had significant

Table II. Statistical comparisons between final samples at T1

HG 1 FA n 5 28 (1) BH 1 FA n 5 28 (2) Controls n 5 28 (3)

Cephalometric measurement Mean SD Mean SD Mean SD 1-3 2-3 1-2

Cranial baseNSBa () 131.4 5.4 131.4 4.9 133.5 3.8 NS NS NS

Maxillary skeletal

SNA () 80.9 3.0 81.4 3.1 80.3 3.3 NS NS NS

Pt A-nasion perp (mm) 0.3 2.2 0.2 2.9 0.1 3.6 NS NS NS

Co-Pt A (mm) 88.2 5.0 90.3 5.4 88.1 4.9 NS NS NS

Mandibular skeletal

SNB () 76.2 2.8 76.6 3.5 75.9 3.0 NS NS NS

Pg-nasion perp (mm) –5.0 5.7 –7.4 6.3 –6.5 6.3 NS NS NS

Co-Gn (mm) 110.8 6.4 113.5 6.5 112.0 6.7 NS NS NS

Co-Go (mm) 54.3 4.8 55.9 4.3 56.0 4.6 NS NS NS

Maxillary/mandibular

ANB () 4.7 1.9 4.8 1.6 4.3 1.4 NS NS NS

Wits (mm) 3.2 1.6 4.0 2.2 3.1 2.0 NS NS NS

Max/mand diff (mm) 22.5 3.5 23.2 3.5 23.6 3.5 NS NS NS

Vertical skeletal

FH to palatal

plane ()

2.9 8.0 1.3 2.3 2.1 3.5 NS NS NS

FH to mandibular

plane ()

20.8 4.9 23.2 5.6 22.5 4.9 NS NS NS

Palatal to mandibular

planes ()

23.5 5.2 21.8 6.3 20.4 6.6 NS NS NS

ArGoMe () 122.6 6.2 123.1 5.7 121.1 6.4 NS NS NS

CoGoMe () 123.8 5.2 123.4 4.4 121.5 5.2 NS NS NS

N to ANS (mm) 52.1 3.8 52.6 2.9 53.0 3.3 NS NS NS

ANS to Me (mm) 64.2 4.9 65.7 5.6 63.6 5.5 NS NS NS

Interdental

Overjet (mm) 8.4 1.5 8.3 1.4 7.2 1.4 † * NS

Overbite (mm) 5.0 1.6 4.2 1.8 4.7 2.0 NS NS NS

Interincisal angle (

) 126.4 9.1 125.3 8.6 130.6 9.3 NS NS NSMolar relationship (mm) –3.5 1.0 –2.8 1.5 –2.3 1.6 † NS NS

Maxillary dentoalveolar

U1 to Pt A vertical (mm) 6.0 2.2 5.2 1.6 4.8 1.8 NS NS NS

U1 to FH () 115.1 8.5 112.6 6.5 110.5 7.3 NS NS NS

Mandibular dentoalveolar

L1 to Pt A-Pg (mm) 0.9 1.9 1.4 1.7 1.5 1.7 NS NS NS

L1 to mandibular

plane ()

97.6 6.3 98.9 7.0 96.4 6.2 NS NS NS

NS , Not significant; Max/mand , Maxillomandibular; diff, differential. *P\0.05; †P\0.01.



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reductions in overjet, overbite, and interincisal angle,

and significant increases in molar relationship. The re-

duction in overbite was significantly greater in the HG

1 FA group than in the BH1FA group.

The change in maxillary incisor position was signif-

icantly greater in the HG 1 FA group when compared

with the untreated controls, thus leading to a more ret-

ruded position of the maxillary incisors in relation to

Table III. Statistical comparison of the changes between T1 and T2 in Class II treated and untreated subjects

HG 1 FA n 5 28 (1) BH 1 FA n 5 28 (2) Cont rols n 5 28 (3)

Cephalometric measurements Mean SD Mean SD Mean SD Diff 1-3 Diff 2-3 Diff 1-2

Cranial baseNSBa () –0.3 1.7 –0.6 1.1 –0.2 1.3 –0.1 –0.4 0.3

Maxillary skeletal

SNA () –0.3 2.9 –0.4 1.3 0.5 1.3 –0.8 –0.9 0.1

Pt A-nasion perp (mm) –0.4 2.7 –1.0 1.0 0.5 1.1 –0.9 –1.5* 0.6

Co-Pt A (mm) 3.0 2.6 2.7 2.9 3.6 2.2 –0.6 –0.9 0.3

Mandibular skeletal

SNB () 0.4 2.0 1.4 1.2 0.7 0.9 –0.3 0.7 –1.0*

Pg-nasion perp (mm) 1.2 3.2 2.7 2.9 0.8 1.8 0.4 1.9* –1.5*

Co-Gn (mm) 7.2 3.1 8.1 3.3 5.2 2.7 2.0* 2.9* –0.9

Co-Go (mm) 5.1 2.3 5.2 2.1 4.3 2.8 0.8 0.9 –0.1

Maxillary/mandibular

ANB () –0.7 1.8 –1.9 1.1 –0.2 0.8 –0.5 –1.7* 1.2*

Wits (mm) –0.9 4.5 –2.6 1.3 0.5 1.5 –1.4 –3.1* 1.6*

Max/mand diff (mm) 4.6 2.5 5.2 1.9 2.7 1.7 1.9* 2.5* –0.6

Vertical skeletal

FH to palatal

plane ()

0.5 2.0 –0.6 1.1 –0.2 1.4 0.7 –0.4 1.1*

FH to mandibular

plane ()

–0.1 1.8 –0.5 1.9 –1.2 1.5 1.1 0.7 0.4

Palatal to mandibular

planes ()

–0.6 2.1 0.1 2.6 –1.0 2.3 0.4 1.1 –0.7

ArGoMe () –1.3 2.3 –1.4 2.3 –1.6 2.2 0.3 0.2 0.1

CoGoMe () –0.4 1.8 –0.8 2.0 –0.6 2.0 0.2 –0.2 0.4

N to ANS (mm) 2.4 2.8 2.7 1.9 2.1 1.4 0.3 0.6 –0.3

ANS to Me (mm) 4.7 2.1 4.3 2.7 2.7 1.4 2.0* 1.6* 0.4

Interdental

Overjet (mm) –3.1 1.4 –3.6 1.5 0.1 1.1 –3.2* –3.7* 0.5

Overbite (mm) –3.4 1.6 –2.0 1.5 –0.1 1.0 –3.3* –1.9* –1.4*

Interincisal angle (

) –5.2 9.3 –2.6 9.2 2.3 5.1 –7.5* –4.9 –2.6Molar relationship (mm) 4.2 1.9 3.7 1.5 0.0 1.4 4.2* 3.7* 0.5

Maxillary dentoalveolar

U1 to Pt A vertical (mm) –1.7 2.6 –0.6 1.6 0.2 0.9 –1.9* –0.8 –1.1

U1 to FH () –1.1 7.8 0.0 8.8 –0.9 2.6 –0.2 0.9 –1.1

U1 horizontal (mm) –0.7 2.5 –0.2 1.6 0.4 1.0 –1.1 –0.6 –0.5

U1 vertical (mm) 0.6 1.5 1.0 2.2 0.6 0.9 0.0 0.4 –0.4

U6 horizontal (mm) 0.7 2.3 0.4 1.2 1.4 1.1 –0.7 –1.0 0.3

U6 vertical (mm) 2.1 1.6 1.5 1.3 1.6 0.8 0.5 –0.1 0.6

Mandibular dentoalveolar

L1 to Pt A-Pg (mm) 1.7 1.7 1.4 1.1 –0.2 1.1 1.9* 1.6* –0.4

L1 to mandibular

plane ()

6.5 4.7 3.1 5.0 5.2 8.9 1.3 –2.1 3.4

L1 horizontal (mm) 0.4 1.1 0.7 1.4 –0.2 1.6 0.6 0.9 –0.4

L1 vertical (mm) 0.9 1.4 1.7 2.0 1.5 1.1 –0.6 0.2 –0.8

L6 horizontal (mm) 2.4 1.3 1.3 1.3 0.9 1.5 1.5* 0.4 1.1*L6 vertical (mm) 3.9 1.4 3.2 1.7 1.4 1.1 2.5* 1.8* 0.7

Soft tissue

A0-VL (mm) –0.7 1.4 –0.4 0.9 0.3 1.2 –1.0 –0.7 0.3

B0-VL (mm) 0.7 2.5 2.1 2.6 0.5 2.7 0.2 1.6* –1.4*

Pg0-VL (mm) 1.1 2.9 2.9 3.8 0.4 2.9 0.7 2.5* –1.8*

*P\0.05; Diff , difference; Max/mand , Maxillomandibular; diff , differential.



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Point A (U1 to Pt A vertical) in the HG 1 FA group.

When compared with the untreated control group, man-

dibular incisor and molar positions were significantly

more altered in both treatment groups, showing more

anteriorly positioned incisors in relation to the Point Ato Pg line and more anteriorly positioned molars in

both treatment groups. The mesial movement of the

mandibular molars was significantly greater in the HG

1 FA group than in the BH 1 FA group.

The analysis of the changes in the soft-tissue mea-

surements between the treated patients and the un-

treated controls showed significantly greater forward

movement of soft-tissue B-point and soft-tissue PG in

the BH 1 FA group compared with both the HG 1

FA and the control groups.

Discriminant analysis was performed on the pre-

treatment cephalometric variables in the BH 1 FA

group on the basis of the amount of advancement of

the chin (Pg0-VL) from T1 to T2. The average difference

between the BH 1 FA group and the untreated Class II

controls (2.5 mm) was chosen as the clear-cut value.

The discriminant function identified 2 significant pre-

treatment variables (F 5 4.48; P \0.01) in predicting

the posttreatment amount of mandibular soft-tissue im-

provement: Co-Go-Me and Pg-nasion perp. The regres-

sion coefficient for Co-Go-Me was negative (the smaller

the angle at T1, the greater the mandibular soft-tissue

advancement at T2). The regression coefficient for

Pg-nasion perp was positive (the greater the measure-

ment at T1, the greater the mandibular soft-tissueadvancement at T2). When Pg-nasion perp was

substituted for Pg0-VL in the discriminant analysis,

the outcomes of the discriminant function did not

change significantly. The classification power of the dis-

criminant analysis was 83%.

DISCUSSION

Our aim in this study was to assess the dental, skel-

etal, and soft-tissue changes of 2 protocols for 1-phase

comprehensive treatment of Class II Division 1 maloc-

clusion (BH 1 FA vs HG1 FA and Class II elastics) atthe pubertal growth spurt. The peculiar features of this

study were the analysis of consecutively treated patientsas part of a series of prolective clinical trials on the or-

thodontic or orthopedic therapy of full-cusp Class II

malocclusion, and the double-blind methodology of

data collection and analysis with a historical sample

of untreated Class II controls at the same skeletal matu-

ration phases as the treated subjects for evaluation of

treatment effectiveness vs physiologic growth in Class

II malocclusion. Our methodology was intended to re-

duce potential selection, susceptibility, and proficiency

biases. In particular, the allocation of patients to the 2

treatment groups on the basis of personal choice re-

sulted in the methodologically favorable feature that

the 2 groups were similar before treatment in their ver-

tical skeletal relationships, severity of malocclusion,and morphologic mandibular characteristics (Table II);

those factors have been related to responsiveness to

Class II treatment.17,30,31

This study was intended to increase the knowledge

about the outcomes of 1-phase Class II treatment with

fixed or functional appliances with respect to the results

of the randomized controlled trials in the last 2 decades.

Limitations of several of those investigations were rela-

tive inconsistency in diagnostic entry criteria for the tri-

als32-34 (eg, diagnosis of Class II malocclusion on the

basis of excessive overjet alone35,36) and use of orthope-

dic appliances for Class II correction at a prepubertal

stage in skeletal maturation,35,36 a time known to be

related to a smaller mandibular skeletal response to

treatment than at a pubertal stage.14-19 All treated sub-

jects in our trial had dentoskeletal Class II malocclu-

sions before therapy, and they received treatment with

either HG or BH during the pubertal growth spurt.

The use of historical controls with untreated Class II

malocclusions, though not ideal, was due mainly to the

ethical issue of leaving subjects with full-cusp Class II

malocclusions without orthodontic treatment during

the pubertal and postpubertal stages of development,

a biologic period that is associated with the most favor-

able treatment effects in Class II patients.14-19 Further-more, analysis of the control group at T1 provided

indications about the diagnostic criteria for Class II mal-

occlusion in terms of dentoskeletal discrepancy to be

used as entry criteria for the patients in the 2 treatment

groups. The untreated longitudinal sample matched the

treated samples also as to skeletal maturation at T1 and

T2, male-to-female ratio, and duration of observation

period.

Both treatment regimens proved to be effective on

occlusal parameters (overjet, overbite, and molar rela-

tionship); this agreed with previous short-term and

long-term reports.4-6,8-14,16,21,22

The success rates interms of overall correction of Class II Division 1 maloc-

clusion were high in both groups, exceeding 90%.Treatment during the peak period induced a significant

increase in mandibular length in both treatment groups

compared with the untreated controls (about 2 mm for

the HG group and about 3 mm for the BH group). As

for vertical skeletal changes, both treatment groups

showed significant increases in lower anterior facial

height compared with the controls. Significant retrusion

of the maxillary incisors and protrusion of the mandi-

buolar incisors were found in the HG group, associated



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with significant mesial and vertical movements of the

mandibular molars. These changes can be seen as con-

sequences of the Class II elastics, used in the Hg 1

FA group. The dental changes were minor in the BH

group.Significant changes in the soft-tissue measurements

were achieved only in the BH group. A significant ad-

vancement of the chin portion of the profile, with

a mean advancement of 2.5 mm at Pg 0, was observed

in the BH 1 FA patients. This result is similar to out-

comes reported by Morris et al37 and Lee et al38 in stud-

ies on soft-tissue changes induced by functional

appliances (Twin-block) and by Flores-Mir and Major39

in a systematic review on the same topic.

All patients in both treatment groups completed

their treatment protocols at advanced postpubertal

stages in skeletal maturation (30% at CS 5, 70% at CS

6). The amount of craniofacial growth after those stages

is limited in Class II subjects, and, more importantly,

growth differences between Class II and normal occlu-sion subjects after late puberty are insignificant.23 When

orthodontic therapy of Class II malocclusion is com-

pleted in late puberty, near the end of active craniofacial

growth, relapse from reestablishment of Class II growth

characteristics is expected to occur less often.23,40

The comparison between the 2 treatment protocols

for Class II malocclusion showed greater skeletal ef-

fects induced by the BH than the HG. These effects

were mainly due to greater impact on the growth and

sagittal position of the mandible that affected favorablythe reduction in the ANB angle and the Wits appraisal.

Maxillary changes induced by the 2 treatment protocols

were similar and, in general, minor. The more signifi-

cant performance of the BH 1 FA protocol than the

Hg 1 FA protocol agrees with previous studies.10-13

Interestingly, the major differential treatment out-

come of the BH protocol with respect to the HG protocol

was the greater favorable change in the position of the

soft tissues of the chin region (about 2 mm more in

the HB 1 FA group than in the HG 1 FA group, and

about 2.5 mm more in the HB 1 FA group than in the

controls). When this outcome was investigated in rela-tion to the pretreatment dentofacial characteristics of

the BH patients, greater improvement in the soft-tissuechin profile was achieved in Class II subjects who had

a smaller Co-Go-Me angle (less obtuse mandibular, or

gonial, angle) and a greater distance from pogonion to

nasion perpendicular (more retruded mandible) before

treatment. Finally, when Pg-nasion perp was substituted

for Pg0-VL in the discriminant analysis, the outcomes of

the discriminant function did not change significantly.

This implies that the position of the chin in Class II pa-

tients before treatment can be diagnosed adequately

with both cephalometric skeletal measurements and

evaluation of the soft-tissue relationships.

From the outcomes of this investigation, it can be

stated that the clinical indication for the preferential

use of a 1-phase comprehensive Class II treatment pro-tocol including the BH (functional jaw orthopedics)

rather than the HG at puberty is the diagnostic presence

of a retruded mandible (Pg-nasion perp,\–7 mm) with

a closed mandibular angle (Co-Go-Me, \ 123).

According to the results of discriminant analysis, these

patients are expected to achieve advancements of the

chin from 2.5 to 5 mm more than untreated Class II sub-

jects, and from 2 to 4 mm more than Class II subjects

treated with the HG protocol. With various combina-

tions of pretreatment dentoskeletal characteristics, the

2 treatment protocols are relatively equivalent in terms

of posttreatment impact on the profile at a late postpu-

bertal evaluation.

The outcomes of the analysis of pretreatment char-

acteristics in relation to effective changes in Class II pa-tients confirm previous data regarding the predictive

role of mandibular morphology on favorable skeletal

changes induced by functional jaw orthopedics at pu-

berty.17,31,41 These previous studies suggested that

greater increases in mandibular length in patients

treated with functional appliances are associated with

small pretreatment values for the Co-Go-Me measure-

ment. Our study indicates that, in these Class II patients,

the favorable mandibular skeletal change might resolve

also in a favorable soft-tissue response at the chin.

CONCLUSIONS

The main findings of this cephalometric trial on the

outcomes of 2 single-phase nonextraction treatment

protocols for Class II malocclusion (HG 1 FA vs

BH 1 FA) were the following.

1. Class II treatment with either protocolduring thepu-

bertal growth spurt induced significant favorable

dentoskeletal changes, with a high success rate at

the occlusal level (correction of overjet and molar

relationship). Dentoalveolar changes were morepronounced in the HG1 FA subjects, whereas man-

dibular modifications were greater in the BH 1 FA

group.

2. The BH 1 FA protocol had a greater favorable

impact on the advancement of the chin as shown

by soft-tissue analysis.

3. The clinical indication for the preferential use of

1-phase comprensive treatment protocol for Class

II malocclusion with the BH at puberty is a small

mandibular angle (Co-Go-Me) and mandibular ret-

rusion before treatment. When treated with the



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BH 1 FA protocol, these Class II patients have the

greatest probability of significant improvement in

the profile by advancement of the soft tissues of

the chin.

We thank James A. McNamara, who treated the

BH 1 FA patients, and John Clinthorne, both of Ann

Arbor, Mich, who treated the HG 1 FA patients; Ali

Darendeliler, Sydney, Australia, and Bjorn Zachrisson,

Olso, Norway, for critical support and advice during

the project; and Michael Powell for editorial assistance.

This article is dedicated to the memory of T. M. Graber.

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