stability of quadhelix crib therapy in

8112019 Stability of Quadhelix Crib Therapy In

httpslidepdfcomreaderfullstability-of-quadhelix-crib-therapy-in 19

Stability of quad-helixcrib therapy indentoskeletal open bite A long-term

controlled study

Manuela Mucederoa Lorenzo Franchib Veronica Giuntinic Andrea Vangelistic James A McNamara Jrd

and Paola Cozzae

Rome and Florence Italy and Ann Arbor Mich

Introduction The purpose of this study was to evaluate the long-term stability of quad-helixcrib treatment

in subjects with dentoskeletal open bite Methods Twenty-eight subjects (11 boys 17 girls mean age

82 6 13 years) were treated consecutively with quad-helixcrib appliances The patients were reevaluated at

the end of active treatment with the quad-helixcrib (mean age 97 6 16 years) and at least 5 years after the

completion of treatment (mean age 146 6 19 years) A control group of 20 untreated subjects with the

same dentoskeletal disharmony was used for the statistical comparison (Mann-Whitney U test) Results In

the long term the quad-helixcrib group showed a signi1047297cant reduction in the ANB angle (13) a downward

rotation of the palatal plane (18) a greater increase in overbite (21 mm) and a decrease in overjet

(15 mm) when compared with the controls Conclusions In the long term the use of the quad-helixcrib

appliance led to successful outcomes in about 93 of the patients considered Correction of dentoskeletal

open bite was associated with a clinically signi1047297cant downward rotation of the palatal plane (Am J Orthod

Dentofacial Orthop 2013143695-703)

A

nterior open bite is characterized by a localizedabsence of occlusion between the incisal edges

of the maxillary and mandibular teeth whenthe remaining teeth are in occlusion12 This

malocclusion occurs because of interferences duringnormal dental eruption and alveolar developmentSeveral factors are involved in the etiology of anterioropen bite3-6 Thumb sucking and increased vertical

skeletal relationships are signi1047297cant risk f actors for theestablishment of an anterior open bite67 Subjects with

dentoskeletal open bite and sucking ha bits often haveconcomitant transverse discrepancies8 Many authors

have emphasized that a skeletal open bite should betreated early in the mixed dentition to allow for normaldevelopment of the anterior dentoalveolar region9-11

Various treatment approaches can be found in theliterature with regard to early treatment of anterioropen bite12-18 The elimination of persisting sucking

habits and the control of the vertical dimension must be therapeutic objectives The correction of maxillary constriction is an additional target for treatment inpatients with open bite19

The use of a palatal crib has been proposed as anexcellent treatment option because it prevents thumb

or paci1047297er sucking as well as tongue thrust320-23

According to Haryett et al22 the palatal crib is effectivefor the elimination of a thumb-sucking habit in 85 to90 of subjects Studies reporting the success of early

treatment in subjects with anterior open bite whencompared with a well-matched control group however

are scarce in the literature Only 2 studies haveincorporated untreated controls with the same type of dentoskeletal disharmony but they were con1047297nedto short-term observations2425 The authors of both

a Research fellow Department of Orthodontics University of Rome ldquoTor Vergatardquo

Rome Italy bAssistant professor Department of Orthodontics University of Florence Flor-

ence Italy Thomas M Graber Visiting Scholar Department of Orthodontics

and Pediatric Dentistry School of Dentistry University of Michigan Ann Arborc

Research associate Department of Orthodontics Universita degli Studi di

Firenze Firenze ItalydThomas M and Doris Graber Endowed Professor of Dentistry Department of

Orthodontics and Pediatric Dentistry School of Dentistry research professor

Center for Human Growth and Development University of Michigan Ann Arbore Professor and chair Department of Orthodontics University of Rome ldquoTor

Vergatardquo Rome Italy

The authors report no commercial proprietary or 1047297nancial interest in the

products or companies described in this article

Reprint requests to Lorenzo Franchi Dipartimento di Odontostomatologia

Universita degli Studi di Firenze Via del Ponte di Mezzo 46-48 50127 Firenze

Italy e-mail lorenzofranchiuni1047297it

Submitted September 2012 revised and accepted January 2013

0889-5406$3600

Copyright 2013 by the American Association of Orthodontists

httpdxdoiorg101016jajodo201301010

695

ORIGINAL ARTICLE



studies analyzed the effects of a removable palatal crib

associated with a vertical-pull chincup this treatmentprotocol did not produce signi1047297cant changes in theskeletal maxillary and mandibular components The

results of both studies showed that the effects of therapy primarily were dentoalveolarA proposed treatment protocol aimed to eliminate

the thumb-sucking habit and to correct both theanterior open bite and the maxillary transversede1047297ciency in growing high-angle subjects is a quad-helix(Q-H) appliance with the addition of a palatal crib

(Q-HC)1725 When compared with the effects of a removable appliance (open-bite bionator orremovable palatal crib) the Q-HC appliance was

shown to be signi1047297cantly more effective in theimprovement of overbite in the short term2627 Thetreatment and posttreatment effects of a Q-HCappliance showed a clinical effectiveness in correcting

the dental open bite of 85 of the patients aftera follow-up of 2 years28 This favorable result wasassociated with clinically signi1047297cant improvement inthe maxillomandibular vertical skeletal relationships

No data however are available in the literature aboutthe outcomes of the Q-HC appliance reevaluated at

a follow-up of at least 5 yearsThe purpose of this study therefore was to evaluate

the long-term stability of Q-HC treatment in subjects with thumb-sucking habits and anterior dentoskeletalopen bite Both active treatment and posttreatment

effects were analyzed in consecutively treated patientsand these results were compared with the growthchanges in an untreated control group with the samedentoskeletal disharmony during a follow-up period of at least 5 years

MATERIAL AND METHODS

The Q-HC sample comprised 28 subjects (17 girls 11

boys) who were treated consecutively at the Departmentof Orthodontics at the University of Rome ldquoTor Vergatardquo

or in a private orthodontic practice in Rome Lateralcephalograms of treated patients were analyzed

regardless of treatment results Each patient had thefollowing features thumb-sucking habit beforetreatment negative overbite constricted maxillary arch as consequence of thumb sucking full eruptionof 1047297rst permanent molars and permanent incisors(to prevent the ldquopseudo-open biterdquo due to undererupted

permanent incisors)29 no permanent teeth extracted

before or during treatment 3 consecutive lateralcephalograms of good quality with adequate landmark

visualization and minimal or no rotation of the headtaken before treatment (T1) at the end of the activetreatment with the Q-HC (T2) and at a follow-up

observation at least 5 years after the completion of

treatment (T3) and treatment with the Q-HC appliancefor at least 12 months17

All subjects were at a prepubertal stage of skeletal

maturity according to the cer vical vertebral maturationmethod (CS 1 or CS 2) at T130 The overall observationperiod was 64 6 14 years which included a follow-

up period of at least 5 years during which the Q-HCpatients were treated with 1047297 xed appliances No active

biomechanics or vertical elastics to extrude the incisors were applied during 1047297 xed appliance therapy No

intraoral Class II elastics were usedAll subjects had reached postpubertal skeletal

maturity at T3 (CS 4-6) The stages of cervical vertebralmaturation were determined by a calibrated examiner(LF) trained in this method All patients were in thepermanent dentition at T3

A control group of 20 subjects (10 girls 10 boys) withanterior open bite was retrieved from the archives of the

University of Michigan Growth Study and the DenverChild Growth Study The control group matched theQ-HC group for negative overbite at T1 chronologicage and skeletal maturation at the various time periods

and for the duration of intervalsThe mean ages at the 3 time periods in both the

Q-HC and control groups and the duration of either treatment or observation intervals are given in

Table IThe Q-H appliance used in this study was made of

0036-in stainless steel wire soldered to bands on thesecond deciduous molars or the 1047297rst permanent molars( Fig)25 The lingual arms of the appliance extendedmesially to the deciduous canines or to the permanentincisors The anterior helices were brought as far forwardon the palate as possible Spurs to prevent thumb

sucking were formed from 3 segments of 0036-instainless steel wire soldered to the anterior bridge of

the Q-H The wire segments were inclined lingually toprevent impingement on the sublingual mucosa25

Activation of the Q-H was equivalent to the buccolingual width of 1 molar The appliance was reactivated once or

twice during treatment to achieve overcorrection of thetransverse relationships

The T1 T2 and T3 cephalograms were hand traced by 1 investigator (VG) and then veri1047297ed for landmarklocation by a second investigator (LF) Any disagree-ments were resolved by retracing the landmark or

structure to the satisfaction of both observersCephalometric software (Viewbox version 30 dHALSoftware Ki1047297ssia Greece) was used for a customizeddigitization regimen that contained 21 variables

(11 linear 10 angular) The magni1047297cation factor of thecephalograms was standardized at 8

696 Mucedero et al

May 2013 Vol 143 Issue 5 American Journal of Orthodontics and Dentofacial Orthopedics



Statistical analysis

Descriptive statistics (mean differences and standarddeviations) were calculated for all cephalometricmeasurements at T1 and for the changes from T1 toT2 T2 to T3 and T1 to T3 in both groups

The homogeneity between the Q-HC and controlgroups for skeletal maturity at each observation timeand mean duration of observation intervals allowed forcomparisons without annualizing the data Matching

between treated and control subjects was tested also

by means of propensity score analysis31 This matching

protocol in observational studies allows researchers tomimic randomization by creating a sample of subjects

who did not receive treatment comparable on allobserved covariates with the sample of subjects whoreceived treatment3233 The program ldquopsmatchingrdquo

33

(available at httpsourceforgenetprojectspsmspss

1047297les) was used to calculate propensity scores and totest matching between the treated and control samples(SPSS version 210 IBM Armonk NY) Propensity scores

were calculated for some clinically relevant covariates(Wits Frankfort horizontal to palatal plane palatal planeto mandibular plane and overbite) whereas all other

variables were entered as additional covariates Anoverall balance chi-square test developed by Hansenand Bowers34 was applied to test group matching Thistest examines all covariates that were used to estimatethe propensity scores and all variables that were de1047297nedas additional covariates

Changes in the 2 groups were compared by

nonparametric tests since normal distribution(Kolmogorov-Smirnov test) or equality of variances(Levene test) could not be assessed for all variables In

general parametric tests are more powerful thannonparametric statistics However the assumptionsrequired for parametric tests are particularly important

when sample sizes are small with small usually thoughtto be fewer than 30 in each group if the assumptionscannot be veri1047297ed then nonparametric methods should

be used35

Before making the comparisons of the longitudinalchanges signi1047297cant differences between the craniofacialstarting forms at T1 were assessed with the

Mann-Whitney U test between the Q-HC and controlgroups To assess the differences between the Q-HCand control groups with regard to T1 to T2 T2 to T3and overall T1 to T3 changes Mann-Whitney U tests

(P 005 P 001 and P 0001) were usedChi-square tests with the Yates correction wereperformed to compare the prevalence rates of correctionof anterior open bite in the 2 groups at T2 and T3 Thecorrection of anterior open bite at the dentoalveolar level

was considered to be obtained when the overbitemeasurement was equal to or greater than 0 mm

The data were analyzed with statistical software (SPSS210 and SigmaStat version 35 Systat Software Point

Richmond Calif) Statistical signi1047297cance was tested atP 005 The power of the study was 091 for an alpha

level of 005 and an effect size equal to 136 for theclinically relevant variable palatal plane to mandibularplane angle as derived from a previous study28

To test the reliability of the measurements 20 lateralcephalograms randomly selected from various subjects inthe study were retraced and remeasured b y the same ex-

aminer (VG) after a 1-month interval37 No systematicerror was found with the Wilcoxon signed rank test

Random errors were estimated with Dahlbergsformula38 The errors for linear measurements rangedfrom 01 mm for pogonion to nasion perpendicular to12 mm for condylion-gonion The errors for angular

measurements ranged from 04

for ANB angle to14 for interincisal angle

RESULTS

Analysis of thestartingforms(TableII)showedthattheQ-HC and the control groups had no statistically signi1047297-

cant differences in craniofacial characteristics at T1 Theonly exception was a signi1047297cantly longer ramus length(Co-Go) at T1 in the Q-HC group For the dentoskeletalfeatures at T1 the vertical skeletal relationship was in-

creased and the sagittal intermaxillary relationship wasskeletal Class II in both groups The overall matching

Table I Demographics of the groups

Chronologic age (y)

Q-HC group (n 5 28) Control group (n 5 20)

Mean SD Mean SD

T1 82 13 81 04T2 97 16 98 04

T3 146 19 145 07

T1-T2 15 04 17 04

T2-T3 49 13 47 06

T3-T1 64 14 64 07

Fig Intraoral view of the Q-HC in place

Mucedero et al 697

American Journal of Orthodontics and Dentofacial Orthopedics May 2013 Vol 143 Issue 5



between the treated and control groups was assessed fur-ther with propensity scores The chi-square balance test

was not statistically signi1047297cant (chi-square 5 28154P 5 0081) thus indicating good overall balance

between the 2 groups

The statistical comparisons of the T1 to T2 changes(Table III) showed no statistically signi1047297cant differences

between the Q-HC and control samples for any maxillary or mandibular skeletal measurements in the

sagittal plane For the vertical skeletal measurementsthe Q-HC group exhibited greater downward rotationof the palatal plane than did the control group(19 mm) A signi1047297cant effect of therapy was found forthe dentoalveolar variables The Q-HC group showed

a signi1047297cantly greater increase in overbite (22 mmmore than the control group) associated with 57 of

lingual tipping of the mandibular incisors relative tothe mandibular plane with respect to the controls

After active treatment (T2) the prevalence rates forcorrection of overbite were 86 (24 subjects) in theQ-HC group and 50 (10 subjects) in the control

group The comparison was statistically signi1047297cant(chi-square 5 558 P 5 0018)

No signi1047297cant differences in posttreatment changes(T2-T3) were found between the Q-HC and controlgroups (Table IV)

The evaluation of the overall treatment changes fromT1 to T3 (Table V) showed signi1047297cant differences in thesagittal skeletal relationships The intermaxillary skeletal

relationships showed a signi1047297cant reduction in the ANB

angle of 13

in the Q-HC group compared with thecontrol group Vertical skeletal variables maintaineda signi1047297cant improvement in the Q-HC group vs thecontrols (Frankfort horizontal to palatal plane 18palatal plane to mandibular plane 22) Overbitehad a signi1047297cantly greater increase in the Q-HC group

(21 mm more than the control group) and a signi1047297cantdecrease was found for overjet in the Q-HC group vs thecontrols (15 mm)

At the follow-up observation (T3) 26 subjects (93)

in the Q-HC group showed a corrected overbite Thisprevalence rate was signi1047297cantly greater than that in the

Table II Comparison of starting forms (T1)

Cephalometric measurement


Difference Signi 1047297cance Mean SD Mean SD

Maxillary skeletalSNA () 821 29 807 32 14 NS

Point A-nasion perp (mm) 24 27 11 30 13 NS

Mandibular skeletal

SNB () 768 32 754 20 14 NS

Pg-nasion perp (mm) 55 66 85 40 30 NS

Co-Gn (mm) 1063 65 1043 39 20 NS

Maxillarymandibular

ANB () 53 24 54 20 01 NS

Wits (mm) 16 27 15 26 01 NS

Vertical skeletal

FH-PP () 31 34 34 28 03 NS

MPA () 285 42 279 44 06 NS

PP-mandibular plane () 315 49 313 40 02 NS

ANS-Me (mm) 651 57 649 41 02 NS

Co-Go (mm) 493 33 472 35 21

Gonial angle () 1317 51 1302 42 15 NS

Interdental

Overjet (mm) 28 29 36 18 08 NS

Overbite (mm) 33 16 22 23 11 NS

Interincisal angle () 1220 97 1257 110 37 NS

Molar relationship (mm) 04 19 08 13 04 NS

Maxillary dentoalveolar

U1-Point A vert (mm) 44 23 38 18 06 NS

U1-FH () 1170 78 1143 68 27 NS

Mandibular dentoalveolar

L1-Point A Pg (mm) 21 21 19 22 02 NS

L1-MPA () 931 60 926 71 05 NS

NS Not signi1047297cant perp perpendicular Pg pogonion FH Frankfort horizontal PP palatal plane U1 maxillary central incisor vert vertical L1

mandibular central incisor NS not signi1047297cantP 005

698 Mucedero et al




control group (15 subjects 70 chi-square 5 290 P 5

0036)

DISCUSSION

The speci1047297c features of this study were the following

1 Patients were treated consecutively they were

included in the study regardless of treatmentoutcome A posttreatment observation (T2) was

obtained at the end of the active treatment withthe Q-HC and a long-term appraisal (T3) wasavailable at least 5 years after treatment

2 The control sample consisted of subjects with

untreated anterior open bite and they matchedthe Q-HC group as to type of dentoskeletalmalocclusion age interval skeletal maturation atdifferent time points and sex distribution(Table I) Although historical control groups might

have limitations39 in our study the use of historical

controls was due to the lack of ethical rationale toleave patients with anterior open bite untreated at

the developmental period (early developmentalphases) that is known as the optimal time for rees-tablishing normal dentoskeletal relationships720

For the same ethical reasons it would beimpossible to collect a contemporary controlgroup of subjects with untreated anterior open

bite with an observation in the long term

All subjects treated with the Q-HC protocol ceased

the thumb-sucking habit as was noted in a previousstudy17 No patient resumed thumb-sucking habitsduring the posttreatment period

The results of the T1 to T2 interval showed nostatistically signi1047297cant differences between the 2 groupsfor the maxillary and mandibular skeletal components or

the maxillomandibular relationships Q-HC therapy produced on average about 20 of downward rotationof the palatal plane with respect to the controls Asa result intermaxillary divergence as measured by theangle between the palatal plane and the mandibularplane exhibited a signi1047297cant mean reduction of about

Table III Comparison of changes during treatment (T1-T2)






Mandibular skeletal

SNB () 11 13 12 32 01 NS


Co-Gn (mm) 41 33 43 19 02 NS

Maxillarymandibular

ANB () 09 13 01 18 08 NS

Wits (mm) 02 24 19 37 21 NS

Vertical skeletal

FH-PP () 17 36 02 25 19

MPA () 06 33 05 36 01 NS

PP-mandibular plane () 22 22 03 21 19

ANS-Me (mm) 09 16 19 15 10 NS

Co-Go (mm) 18 28 21 22 03 NS

Gonial angle () 17 27 12 31 05 NS

Interdental

Overjet (mm) 03 22 10 13 01 NS

Overbite (mm) 42 18 20 16 22 y





U1-FH () 03 61 12 56 09 NS


L1-Point A Pg (mm) 08 19 05 12 13 NS

L1-MPA () 37 58 20 28 57 y


mandibular central incisorP 005 yP 001

Mucedero et al 699




20 in the Q-HC compared with the controls This1047297nding demonstrates that treatment with the Q-HCproduces favorable skeletal control of the verticaldimension in the short term

These 1047297ndings were similar to those described ina previous short-term study that reported a signi1047297cantly

greater downward rotation (12) of the palatal planeassociated with a signi1047297cant reduction in the intermax-illary divergence (17) in the Q-HC sample withrespect to the controls at the end of the active

treatment17

On the other hand our short-termtreatment outcomes disagreed with those of Pedrinet al23 and Torres et al24 The results of both studiesshowed that the effects of therapy primarily weredentoalveolar without signi1047297cant changes in the skeletalmaxillary and mandibular components The initial mean

amount of negative overbite (a measure of anteriordentoalveolar open bite) was 33 mm in the Q-HCgroup The average increase in overbite (42 mm) duringQ-HC therapy overcorrected the amount of anterior

open bite at T2 This value was statistically signi1047297cant when compared with the control group

This result agrees with the outcome at the end of active therapy with the same treatment protocolreported in a previous short-term study17 Similarly inthe short-term results of Pedrin et al23 the treated group

showed a signi1047297cant closure of the anterior open bite of 50 mm whereas Torres et al24 found an improvement in

overbite of 39 mm In our study a statistically signi1047297-cant lingual tipping (37) of the mandibular incisorsto the mandibular plane contributed to the correctionof overbite in the Q-HC group This treatment effect

could be due to the normalization of function such aselimination of tongue thrusting and interruption of sucking habits encouraged by the palatal crib40

The statistical data can be accompanied by the analysis of individual data 24 of 28 subjects showed positiveoverbites at T2 Therefore in this study we assessed the

clinical effectiveness for the treatment protocol in ap-proximately 86 of patients with dentoalveolar open

bite at the end of active therapy The failure of overbitecorrection in the other 4 subjects was attributable to

their higher values for anterior open bite at T1 Theprevalence rate for the success of Q-HC therapy appears

Table IV Comparison of changes after treatment (T2-T3)






Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS


mandibular central incisor

700 Mucedero et al




as a favorable result and the prevalence is similar to thesuccess rates reported in other studies on the early treatment of anterior open bite (80 according Torres

et al23 and Pedrin et al24 90 according Cozzaet al28) In our study only 10 of the 20 subjects (50)

of the control group showed spontaneous correctionof anterior open bite Comparison between prevalencerates of overbite correction at T2 was statistically signi1047297cant demonstrating the ef 1047297cacy of treatment

In the posttreatment period (T2-T3) no signi1047297cantchanges in the Q-HC subjects over the controls werefound Therefore no relapse in overbite was noted afteractive treatment

The analysis of the overall results (Table V) showedthat intermaxillary sagittal skeletal relationships

exhibited favorable changes compared with the controlgroup with a decrease in the ANB angle of 13 Withrespect to vertical skeletal features the overall changesre1047298ected the T1 to T2 changes The outcomes of Q-HC therapy produced a clinically signi1047297cantdownward rotation of the palatal plane of 18 with

a signi1047297cant improvement in maxillomandibulardivergence of 22 in the Q-HC group vs the controlsubjects This favorable outcome deserves to be

emphasized because of its clinical impact ondentoskeletal open bite it contributes to the overall

correction of anterior open bite signi1047297cantly No previous clinical investigation has evaluated the

effects of early correction of anterior open reevaluatedat a 5-year follow-up with respect to a control sample

with untreated anterior open bite Only 1 study hasaddressed early correction with the Q-HC appliance of anterior open bite in mixed-dentition patients with anadequate sample size and a control group28 Evaluationof the results after 2 years of active treatmentshowed clinically signi1047297cant improvements in both

maxillomandibular vertical skeletal relationship (25)

and overbite (27 mm)At a follow-up observation of 5 years favorable

changes in anterior dentoalveolar relationships werefound An improvement in the sagittal skeletalrelationships (ANB 13 in the Q-HC vs the control)

Table V Comparison of long-term changes (T1-T3)






Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701




was associated with a signi1047297cant reduction of 15 mm in

overjet (15 mm in the Q-HC vs the control) The Q-HC group also showed a signi1047297cant improvement in over-

bite (21 mm) compared with the controls The mean

overbite increase in the Q-HC group was 49 mm pro- viding correction of the anterior open bite in 26 subjects with a prevalence rate of 93 This value was signi1047297-

cantly greater than that of the control group (70)and it also was greater than that reported in the previousstudy that assessed the clinical effectiveness for the sametreatment protocol in approximately 85 of patients28

The 23 gain in therapeutic effect can be consideredclinically signi1047297cant since it was achieved with a rela-tively minimal burden on both the clinician and the pa-

tient The appliances used were noncompliance devicesduring 1047297 xed appliance therapy no auxiliaries (eg verti-cal or sagittal elastics) were applied The results of thisstudy showed that in the long term the elimination of

oral habits permitted the normalization of function fa- voring improved facial growth in both the sagittal and vertical planes

CONCLUSIONS

The treatment effects of the Q-HC protocol ingrowing subjects with thumb-sucking habits and

anterior open bite were compared with the growthchanges in untreated subjects with the same dentoskele-tal disharmony during a follow-up period of 5 years

1 In the long term the Q-HC appliance led tosuccessful outcomes in 93 of the patients anda mean closure of the anterior open bite of about5 mm

2 The Q-HC protocol produced a clinically signi1047297cant

downward rotation of the palatal plane Thisfavorable outcome contributed signi1047297cantly to theoverall correction of the anterior open bite with animprovement in the vertical skeletal relationships

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3 Huang GJ Justus R Kennedy DB Kokich VG Stability of anterior

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a Class II open bite malocclusion Am J Orthod Dentofacial Orthop

1996110598-605

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sion in 4-6 year old Brazilian childrenJ Clin Pediatr Dent 200227

81-5

6 Cozza P Baccetti T Franchi L Mucedero M Polimeni A Sucking

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128517-9

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children a longitudinal study Eur J Orthod 200830580-5

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et al Malocclusions and non-nutritive sucking habits a prelimi-

nary study Prog Orthod 201112114-8

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1454-60

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treatment of skeletal open bite Eur J Orthod 199214207-1514 Kuster R Ingervall B The effect of treatment of skeletal open bite

with two types of bite-blocks Eur J Orthod 199214489-99

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with the open bite bionator Am J Orthod Dentofacial Orthop

1992101367-74

16 Schulz SO McNamara JA Jr Baccetti T Franchi L Treatment

effects of bonded RME and vertical-pull chincup followed by 1047297 xed

appliance in patients with increased vertical dimension Am J

Orthod Dentofacial Orthop 2005128326-36

17 Cozza P Baccetti T Franchi L McNamara JA Jr Treatment effects

of a modi1047297ed quad-helix in patients with dentoskeletal open bites


18 Aznar T Galan AF Marin I Dominguez A Dental arch diameters

and relationships to oral habits Angle Orthod 200676441-5

19 Haryett RD Hansen FC Davidson PO Sandilands ML Chronic

thumb-sucking the psychologic effects and the relative

effectiveness of various methods of treatment Am J Orthod

196753569-85

20 Parker JH The interception of the open bite in the early growth

period Angle Orthod 19714124-44

21 Madiraju GS Arika L Effectiveness of appliance therapy in

reducing overjet and open bite associated with thumb sucking

habit Minerva Stomatol 201160333-8

22 Haryett RD Hansen FC Davidson PO Chronic thumb-sucking

a second report on treatment and its psychologic effects Am J

Orthod 197057164-78

23 Pedrin F Almeida MR Almeida RR Almeida-Pedrin RR TorresF A

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appliance with palatal crib combined with high-pull chincuptherapy in anterior open-bite patients Am J Orthod Dentofacial

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24 Torres F Almeida RR de Almeida MR Almeida-Pedrin RR

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25 Cozza P Giancotti A Rosignoli L Use of a modi1047297ed quad-helix in

early interceptive treatment J Clin Orthod 200034473-6

26 Cozza P Baccetti T Franchi L Mucedero M Comparison of 2 early

treatment protocols for open-bite malocclusions Am J Orthod

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letal changes associated with 1047297 xed and removable appliances with

702 Mucedero et al




a crib in open-bite patients in the mixed dentition Am J Orthod


28 Cozza P Mucedero M Baccetti T Franchi L Treatment and

posttreatment effects of quad-helixcrib therapy of dentoskeletal

open bite Angle Orthod 200777640-5

29 Graber TM Rakosi T Petrovic A Dentofacial orthopedics withfunctional appliances St Louis Mosby 1997

30 Baccetti T Franchi L McNamara JA Jr The cervical vertebral

maturation (CVM) method for the assessment of optimal

treatment timing in dentofacial orthopedics Semin Orthod

200511119-29

31 Rubin DB Matching to remove bias in observational studies

Biometrics 197329159-83

32 Rosenbaum PR Rubin DB Constructing a control group using

multivariate matched sampling methods that incorporate the

propensity score Am Stat 19853933-8

33 Thoemmes F Propensity score matching in SPSS 2012 Available

at httparxivorgftparxivpapers120112016385pdf

34 Hansen BB Bowers J Covariate balance in simple strati1047297ed and

clustered comparative studies Stat Sci 200823219-36

35 Sedgwick P Parametric v non-parametric statistical tests BMJ

2012344e175336 Cohen J A power primer Psychol Bull 1992112155-9

37 Houston WJ The analysis of errors in orthodontic measurements

Am J Orthod 198383382-90

38 Dahlberg G Statistical methods for medical and biological

students New York Interscience Publications 1940

39 Pandis N Use of controls in clinical trialsAm J Orthod Dentofacial

Orthop 2012141250-1

40 da Silva Filho OG Gomes Goncalves RJ Maia FA Sucking habits

clinical management in dentistry Pediatr Dent 199115

137-56

Mucedero et al 703



studies analyzed the effects of a removable palatal crib

associated with a vertical-pull chincup this treatmentprotocol did not produce signi1047297cant changes in theskeletal maxillary and mandibular components The

results of both studies showed that the effects of therapy primarily were dentoalveolarA proposed treatment protocol aimed to eliminate

the thumb-sucking habit and to correct both theanterior open bite and the maxillary transversede1047297ciency in growing high-angle subjects is a quad-helix(Q-H) appliance with the addition of a palatal crib

(Q-HC)1725 When compared with the effects of a removable appliance (open-bite bionator orremovable palatal crib) the Q-HC appliance was

shown to be signi1047297cantly more effective in theimprovement of overbite in the short term2627 Thetreatment and posttreatment effects of a Q-HCappliance showed a clinical effectiveness in correcting

the dental open bite of 85 of the patients aftera follow-up of 2 years28 This favorable result wasassociated with clinically signi1047297cant improvement inthe maxillomandibular vertical skeletal relationships

No data however are available in the literature aboutthe outcomes of the Q-HC appliance reevaluated at

a follow-up of at least 5 yearsThe purpose of this study therefore was to evaluate

the long-term stability of Q-HC treatment in subjects with thumb-sucking habits and anterior dentoskeletalopen bite Both active treatment and posttreatment

effects were analyzed in consecutively treated patientsand these results were compared with the growthchanges in an untreated control group with the samedentoskeletal disharmony during a follow-up period of at least 5 years

MATERIAL AND METHODS

The Q-HC sample comprised 28 subjects (17 girls 11

boys) who were treated consecutively at the Departmentof Orthodontics at the University of Rome ldquoTor Vergatardquo

or in a private orthodontic practice in Rome Lateralcephalograms of treated patients were analyzed

regardless of treatment results Each patient had thefollowing features thumb-sucking habit beforetreatment negative overbite constricted maxillary arch as consequence of thumb sucking full eruptionof 1047297rst permanent molars and permanent incisors(to prevent the ldquopseudo-open biterdquo due to undererupted

permanent incisors)29 no permanent teeth extracted

before or during treatment 3 consecutive lateralcephalograms of good quality with adequate landmark

visualization and minimal or no rotation of the headtaken before treatment (T1) at the end of the activetreatment with the Q-HC (T2) and at a follow-up

observation at least 5 years after the completion of

treatment (T3) and treatment with the Q-HC appliancefor at least 12 months17

All subjects were at a prepubertal stage of skeletal

maturity according to the cer vical vertebral maturationmethod (CS 1 or CS 2) at T130 The overall observationperiod was 64 6 14 years which included a follow-

up period of at least 5 years during which the Q-HCpatients were treated with 1047297 xed appliances No active

biomechanics or vertical elastics to extrude the incisors were applied during 1047297 xed appliance therapy No

intraoral Class II elastics were usedAll subjects had reached postpubertal skeletal

maturity at T3 (CS 4-6) The stages of cervical vertebralmaturation were determined by a calibrated examiner(LF) trained in this method All patients were in thepermanent dentition at T3

A control group of 20 subjects (10 girls 10 boys) withanterior open bite was retrieved from the archives of the

University of Michigan Growth Study and the DenverChild Growth Study The control group matched theQ-HC group for negative overbite at T1 chronologicage and skeletal maturation at the various time periods

and for the duration of intervalsThe mean ages at the 3 time periods in both the

Q-HC and control groups and the duration of either treatment or observation intervals are given in

Table IThe Q-H appliance used in this study was made of

0036-in stainless steel wire soldered to bands on thesecond deciduous molars or the 1047297rst permanent molars( Fig)25 The lingual arms of the appliance extendedmesially to the deciduous canines or to the permanentincisors The anterior helices were brought as far forwardon the palate as possible Spurs to prevent thumb

sucking were formed from 3 segments of 0036-instainless steel wire soldered to the anterior bridge of

the Q-H The wire segments were inclined lingually toprevent impingement on the sublingual mucosa25

Activation of the Q-H was equivalent to the buccolingual width of 1 molar The appliance was reactivated once or

twice during treatment to achieve overcorrection of thetransverse relationships

The T1 T2 and T3 cephalograms were hand traced by 1 investigator (VG) and then veri1047297ed for landmarklocation by a second investigator (LF) Any disagree-ments were resolved by retracing the landmark or

structure to the satisfaction of both observersCephalometric software (Viewbox version 30 dHALSoftware Ki1047297ssia Greece) was used for a customizeddigitization regimen that contained 21 variables

(11 linear 10 angular) The magni1047297cation factor of thecephalograms was standardized at 8

696 Mucedero et al











33









be used35













RESULTS





Chronologic age (y)


Mean SD Mean SD

T1 82 13 81 04T2 97 16 98 04

T3 146 19 145 07

T1-T2 15 04 17 04

T2-T3 49 13 47 06

T3-T1 64 14 64 07


Mucedero et al 697

















angle of 13











Mandibular skeletal

SNB () 768 32 754 20 14 NS


Co-Gn (mm) 1063 65 1043 39 20 NS

Maxillarymandibular

ANB () 53 24 54 20 01 NS

Wits (mm) 16 27 15 26 01 NS

Vertical skeletal

FH-PP () 31 34 34 28 03 NS

MPA () 285 42 279 44 06 NS


ANS-Me (mm) 651 57 649 41 02 NS

Co-Go (mm) 493 33 472 35 21

Gonial angle () 1317 51 1302 42 15 NS

Interdental

Overjet (mm) 28 29 36 18 08 NS

Overbite (mm) 33 16 22 23 11 NS





U1-FH () 1170 78 1143 68 27 NS


L1-Point A Pg (mm) 21 21 19 22 02 NS

L1-MPA () 931 60 926 71 05 NS



698 Mucedero et al





0036)

DISCUSSION






















Mandibular skeletal

SNB () 11 13 12 32 01 NS


Co-Gn (mm) 41 33 43 19 02 NS

Maxillarymandibular

ANB () 09 13 01 18 08 NS

Wits (mm) 02 24 19 37 21 NS

Vertical skeletal

FH-PP () 17 36 02 25 19

MPA () 06 33 05 36 01 NS


ANS-Me (mm) 09 16 19 15 10 NS

Co-Go (mm) 18 28 21 22 03 NS

Gonial angle () 17 27 12 31 05 NS

Interdental

Overjet (mm) 03 22 10 13 01 NS

Overbite (mm) 42 18 20 16 22 y





U1-FH () 03 61 12 56 09 NS


L1-Point A Pg (mm) 08 19 05 12 13 NS

L1-MPA () 37 58 20 28 57 y



Mucedero et al 699







treatment17


















Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS



700 Mucedero et al
























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703










33









be used35













RESULTS





Chronologic age (y)


Mean SD Mean SD

T1 82 13 81 04T2 97 16 98 04

T3 146 19 145 07

T1-T2 15 04 17 04

T2-T3 49 13 47 06

T3-T1 64 14 64 07


Mucedero et al 697

















angle of 13











Mandibular skeletal

SNB () 768 32 754 20 14 NS


Co-Gn (mm) 1063 65 1043 39 20 NS

Maxillarymandibular

ANB () 53 24 54 20 01 NS

Wits (mm) 16 27 15 26 01 NS

Vertical skeletal

FH-PP () 31 34 34 28 03 NS

MPA () 285 42 279 44 06 NS


ANS-Me (mm) 651 57 649 41 02 NS

Co-Go (mm) 493 33 472 35 21

Gonial angle () 1317 51 1302 42 15 NS

Interdental

Overjet (mm) 28 29 36 18 08 NS

Overbite (mm) 33 16 22 23 11 NS





U1-FH () 1170 78 1143 68 27 NS


L1-Point A Pg (mm) 21 21 19 22 02 NS

L1-MPA () 931 60 926 71 05 NS



698 Mucedero et al





0036)

DISCUSSION






















Mandibular skeletal

SNB () 11 13 12 32 01 NS


Co-Gn (mm) 41 33 43 19 02 NS

Maxillarymandibular

ANB () 09 13 01 18 08 NS

Wits (mm) 02 24 19 37 21 NS

Vertical skeletal

FH-PP () 17 36 02 25 19

MPA () 06 33 05 36 01 NS


ANS-Me (mm) 09 16 19 15 10 NS

Co-Go (mm) 18 28 21 22 03 NS

Gonial angle () 17 27 12 31 05 NS

Interdental

Overjet (mm) 03 22 10 13 01 NS

Overbite (mm) 42 18 20 16 22 y





U1-FH () 03 61 12 56 09 NS


L1-Point A Pg (mm) 08 19 05 12 13 NS

L1-MPA () 37 58 20 28 57 y



Mucedero et al 699







treatment17


















Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS



700 Mucedero et al
























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703
















angle of 13











Mandibular skeletal

SNB () 768 32 754 20 14 NS


Co-Gn (mm) 1063 65 1043 39 20 NS

Maxillarymandibular

ANB () 53 24 54 20 01 NS

Wits (mm) 16 27 15 26 01 NS

Vertical skeletal

FH-PP () 31 34 34 28 03 NS

MPA () 285 42 279 44 06 NS


ANS-Me (mm) 651 57 649 41 02 NS

Co-Go (mm) 493 33 472 35 21

Gonial angle () 1317 51 1302 42 15 NS

Interdental

Overjet (mm) 28 29 36 18 08 NS

Overbite (mm) 33 16 22 23 11 NS





U1-FH () 1170 78 1143 68 27 NS


L1-Point A Pg (mm) 21 21 19 22 02 NS

L1-MPA () 931 60 926 71 05 NS



698 Mucedero et al





0036)

DISCUSSION






















Mandibular skeletal

SNB () 11 13 12 32 01 NS


Co-Gn (mm) 41 33 43 19 02 NS

Maxillarymandibular

ANB () 09 13 01 18 08 NS

Wits (mm) 02 24 19 37 21 NS

Vertical skeletal

FH-PP () 17 36 02 25 19

MPA () 06 33 05 36 01 NS


ANS-Me (mm) 09 16 19 15 10 NS

Co-Go (mm) 18 28 21 22 03 NS

Gonial angle () 17 27 12 31 05 NS

Interdental

Overjet (mm) 03 22 10 13 01 NS

Overbite (mm) 42 18 20 16 22 y





U1-FH () 03 61 12 56 09 NS


L1-Point A Pg (mm) 08 19 05 12 13 NS

L1-MPA () 37 58 20 28 57 y



Mucedero et al 699







treatment17


















Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS



700 Mucedero et al
























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703




0036)

DISCUSSION






















Mandibular skeletal

SNB () 11 13 12 32 01 NS


Co-Gn (mm) 41 33 43 19 02 NS

Maxillarymandibular

ANB () 09 13 01 18 08 NS

Wits (mm) 02 24 19 37 21 NS

Vertical skeletal

FH-PP () 17 36 02 25 19

MPA () 06 33 05 36 01 NS


ANS-Me (mm) 09 16 19 15 10 NS

Co-Go (mm) 18 28 21 22 03 NS

Gonial angle () 17 27 12 31 05 NS

Interdental

Overjet (mm) 03 22 10 13 01 NS

Overbite (mm) 42 18 20 16 22 y





U1-FH () 03 61 12 56 09 NS


L1-Point A Pg (mm) 08 19 05 12 13 NS

L1-MPA () 37 58 20 28 57 y



Mucedero et al 699







treatment17


















Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS



700 Mucedero et al
























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703






treatment17


















Mandibular skeletal

SNB () 02 24 09 37 07 NS


Co-Gn (mm) 101 64 115 32 14 NS

Maxillarymandibular

ANB () 10 20 05 16 05 NS

Wits (mm) 08 42 04 49 04 NS

Vertical skeletal

FH-PP () 06 35 05 19 01 NS

MPA () 27 30 23 25 04 NS


ANS-Me (mm) 54 38 57 25 03 NS

Co-Go (mm) 54 52 65 33 11 NS

Gonial angle () 43 31 32 33 11 NS

Interdental

Overjet (mm) 09 20 00 20 09 NS

Overbite (mm) 07 16 06 18 01 NS





U1 to FH () 12 71 05 46 07 NS


L1-Point A Pg (mm) 19 26 04 14 15 NS

L1-MPA () 45 68 04 38 41 NS



700 Mucedero et al
























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703























Mandibular skeletal

SNB () 13 23 21 35 08 NS


Co-Gn (mm) 142 61 158 44 16 NS

Maxillarymandibular

ANB () 19 19 06 17 13

Wits (mm) 06 36 23 37 17 NS

Vertical skeletal

FH-PP () 11 29 07 17 18

MPA () 32 27 28 37 04 NS


ANS-Me (mm) 63 33 77 31 14 NS

Co-Go (mm) 71 51 85 39 14 NS

Gonial angle () 60 42 45 36 15 NS

Interdental

Overjet (mm) 06 27 09 20 15

Overbite (mm) 49 20 28 17 21 y





U1-FH () 10 84 07 63 17 NS


L1-Point A Pg (mm) 10 23 09 18 01 NS

L1-MPA () 08 61 24 49 16 NS



Mucedero et al 701












CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703











CONCLUSIONS






REFERENCES








1996110598-605



81-5




128517-9






Orthop 2007132226-9










1454-60






1992101367-74













196753569-85








Orthod 197057164-78




Orthop 2006129418-23












702 Mucedero et al













200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703












200511119-29













Am J Orthod 198383382-90




Orthop 2012141250-1



137-56

Mucedero et al 703

stability of quadhelix crib therapy in

Documents