Chewing pattern before and after unilateral posterior cross-bite therapy with function generating bite: a case report

i

ùo-cs-i"riis _{cnd chev,,,ing ?cÌiern}

!!"yi:rg

pottern

bef_ore

_{ond ofrer unilorersl}

posterior

_cross-bire

_rheropt

_;lrh

_f;;;ii",

generoting bite:

o

cqse

report

/\4orio

_Giozio

pioncino

*,

_Froncesco

Tolpone * *

Cesore Debernordi*

**",

_Pieir-o

gpoaao*****

UniversÌry_of Turin, Deportmeni

_of

_{Biomed;cor sciences qnd}

Choir

of

Orfiodoniics.

_{School of Orihodontics.}

Deqn prof.

.flD

_{in Gnoihology}

onC _{Mosticoiory Fun.lon}

" *Specìolizction in Crthcdontics

*

_"

"Student in Crthodontics

"

"

- *Professor in Odontoslcnrothclog.,r *****n I

l'rotesscr ìn

crthoconrics,

Director of

fie

School of crrhodontic.s

CcresDoir.dence lc,:

Mirlc

Grc:ic

Picrrcino

,:.sc -ìc,:ìiciii, 3B

-

i Cl 26 Torinc _ lioti, Fox: +;Ì? O

ì

1

.c6j32

562

i E-r,cil: n rpicncrQiiri. it

oJrs*lvet'

To _{evoluoie the}

_chewingcycle

closing

_{djreciion of o}

_potient

_with

_o

_posterior

unìloterol cross,

bite'

before treoiment,

six

months

_{ond on* yuoi}

_oftu,.

_{.orru.tin[ìne}

molocclusion

_{wifh o}

_lunction

ge-neroiing bite'

Methods

ond

moleriols.

_{An Syeor-old}

_gi,.l

_*iih

_right

uniloterol

posierior

cross-bire

wos

ireoied with o

function

_generoiing

_bite,

_which

_.orr"."t"d

tr.,"

..J.r-uir"

within

5

monrhs.

Mondibulor

movements

_during

_mosticotion

_oio

soft

_{ond of}

_o

_hord

_u.rrt

_*.r"

recorded before ond ofier

treot-ment

wìth

o

K6

I

kinesiogroph

_{(Myokonics lnc., seottle,}

_we

_uiny

ks-gh.

lnitiolly,

ther,e

wos o

mor-ked prevolence

of

_{chewìng cycies'with}

_o

_reverse

direction of

.lo.rr"

_l9Z%

_{forthe soft bolus}

_{ond g2%}

for ihe

hord

bolus)

during

mosticolion

_on

_{the cross-bite}

_side

_six

months

ofter

_{correction, durìng}

mo-siicoiion on

rhe

corrected

_side,

_the

_{percenro_ge}

_{of chewing}

t

i.,

;;il;#;";;'r'J'l".r"or"d

_,o

2%lor

the

_{sofiond 0% for}

_the

_toti

_{uotrr- rnis decreoreiv-Jr}

rtit

uuia"nt

one

yeor qfter

correction

{0%

for

the

soft

bolus

ond l8%

for

the

hord

bolus).

r*"rii."ri"r'on-the

_{heolthy side}

_{ot oll}

_times

pre-senled cycles

with

normol closing

_{direciion. Con.lrrionr.}

_n*ryrir-.r

mosticoiory

cycles

recorded

be-fore ond ofier orthodontic

_therop)

_ti"*"J

_irrrt

not

only

*o,

_onl"ric

_{correciion ochieved by}

the

func-tion

_{generoting biie,}

_{bui olso}

_thoi

mosticotory funcilo'n

_il;;;"d

_{equilibrium ond}

symmetry ond

bofh

were

_{sioble ot}

_leost

_i

_{yeor ofier}

_{the crors bite}

wos

corrected.

iicncino ir'\G, Tc;o'-rne F, Bcie T, Re.,,,eiciic i.*. Deber-n.,,-.ii

a-

ir.-.^^^ p

.L--,.^;i.rg _{pctiern beiore ,:nc ciier u,.iioieroi}

r.r*ii.rì.,r:É;.;;;

,; l,

fu;,:_

tion gene:ctirg bìte: o ccse .epori _{prsg C.rt,-oJ}

_iCòZ;gi

ìj:24_g6

Tonio

Boie***,

_{Motieo Re'erdito**}

Humon

Cncologyi

Direcior prof.

_G.

_Bussoloti

P

Brocco

-J.A

Cics-.-brle cnci 6.hs,s",!11ci _{eciìern Z}

lntroduciion

Cross-biie is

o

widespreod _{moloc_} clusion

ond

the prevolence

ìs

re-ported to ronge frcm B% ro Z2%1,2. ln c _{siudv by ihe Deporimeni of} Or-ihodontics, _Universiry

_of

_{Turin, of}

ì

253

_{subiects wrth molocclusìons,}

oged

6 to

ì _{6 yeors, cross-bite rvos} found io be preseni in ) 6%of cqses onC holf of these _{were posierior} unr-loterol cross-bite {5 l% on rhe right, 49% on the left)3.

Pcsierior uniloierol cross-bìie

be-comes clinicolly evideni beiween

I B months _{ond 5 yeors of oge4,s}

during erupiion

of

the deciduous ieelh ond _{moy subsequenfly}

invol-v-^ ihe permonent dentìtìon. It ihus

cfiecis children in eorly chilclhocd ot

o

time when oll componenis

ol

the stomctognolhic systern ore still

developing

_{including the}

neurolo-gicol

moior _{schemes_ tlre generol} mcior schemes

cnd

those reioiing

io

lhe _{stomoiognoihic}

s/sie66,7,8-The functionol ospecis of cross-biÌe

lrci,e

been

studied

by

meons of

elecirogncihogroph.v

_Lewin

exc-mined mondibulor kinetics r,,ith o

sì-rogncthogroph

_ond

_deiermined

ihol _{sub;ects in,ith posterior}

uniloie-rol cross-bite preseni

o

morked

pre-volence

_cf

reverse

sequencing

whlch

relotes

io

fie

movement of

the

mondible during

rhe closing

phose of ihe chewìng c'/cl-.e, ì0, t

t-The normol mostlcoÌory poiiern ìn

the

_{froniol plone is}

_{chorociei-tzeC}

b), q _{Cispiocemeni of lhe}

_mcniibje

dcwnwcrd

,J,tring

_ihe

_open,ng

phose ond o de,,,iction tc the bclus

side _{Curing ihe} closing _phose;

du-ring

mosticoiion

on

the

righi,

mo-sticoior,,u _{cycles prevolenfly hcve o} clockwise clcsing direction; dui-ing mosricotion on ihe left the,,, q1s

1s-gulorly counter-clockivisel ì

.

ln ihe presence of posterior uniloie-rol cross-bite, the monCible Cevicles

io _{ihe opposiie side of the bolus} du-ring _{ihe closing phcse of the cycle}

orrd this poitern or closure is colleC "reverse sequencing po1iern". A pre-sumed reoson lor ihis _{oiiered poih of}

closure

is

nci to

domoge ihe

vo-rious components

of

fhe

stomofo-gnothic svsiem involved in

mostìco-iion, ond to bring the

bolus

up ogcrinsi u,ider

iooih

sui-foces, ,,viih

consequeni increcsed mosticoiorir

eiliciencylì,i2.

ln

*e

presence

ci

rìqhl uniloierol pcsterior cross-bile.

obie,ltivo'

Lo scopo

di

questo

lavoro

_è

l'onalisi

dello

direzione

_di

_{chiusura de! paltern masticatorio in unq}

bambino

con

crossbite mo.nolaterale

_{posferiore, primo}

_della

_lerapio

ortodontica con

placco

funziono-lizzonte' dopo

sei rnesl

e

dopo

un

anno

dollo

,oo.riorulJto

_{,lJlrrrturione.}

_lvloferiali

e metodr. È

sio-ta

esaminato

_una

_paziente,

_di

_{sesso femminile,}

di

I

anni,

,on

,roo,

incrociato monolaterole posterio

re

desfro'

L'apporecchiofura

_{funzionolizzonte}

_ha

portoto

oiù

"oir".ione

de/

crossb ite

in

5

mesi. La

ci-netico mondibolare

e

sioio

registrato duronte

lo

mosticazioru

_di

_,n

_bolo

_{nolle e}

_di

_un

_bolo

_duro

con

il

kinesiogrofo

_K6l

_{{Myolronics-lnc., seoftle,}

wA-usA)

_{Rrsu/toii. lnizialnente}

_i

_risultati

_hanno

_dimostrato

uno

netta

prevalenzo

_{di cicli}

_con

_direzione

_d,i

chius.iro

iruurro

'yizz

p",

il

bolo

molle

e

g2%

per

il

bo

lo duro)

durante

_la

masticazione

_dol

_lato

_{delcrossbiie.}

_eZ

_*iriarila

correzione,

durante

lo

mostico-zione

_dal

lato

corretta,

_lo

percentuale

_di

_cicli

_con

_direziotn"

att

,tìrrr*

inversa

è

diminuito

in

_modo

si-gnificotivo (2%

per

ilbolo

molle e

o%

per

il

bolo

duro),

co,ri

rrr,"'

,a

foilow up

o

I

_{anno lo%}

per

ilbo

lo

molle

_e

t8%

per

ilbolo

duro)-

Lo

masticozione

_ayttrx.roro

fr"run

tova sempre

_ciclicon

_direzione

di chiusuro normole prevalente' éonclusionti. L'onalisi deicicli

**tlrt

_ri

_primo

_e

_{dopo terapia ortodontico} nel coso preseniofo

_ha

dimostroto

che, olfre

alla

correzior"

r""r;.o

_{denfoo/ve,olor"}

_,ttunuto

con

ap

porecchiotura

_{fuzionolizzanfe,}

si

è

oltenuto onche

il

,i"quit;ir:i

u

lo

simmetrizzazione

_dello

funzianoli-tà

mosÌicataria

onche

dopa

I

anno

_{dolla correzioned"i}

_ro.ro

_incrociafo.

Key

words:

Cross-bite;

_Crthodoniic;

_{Funciioncl Spplionces; Chewing}

)rt

u"-tcs-§-Dil6 c

!É

ahey,ina poffalii

during mosticction on ihe cross-bite side the cycles

ivill

hove o counter-clockwise closing directìon, insteod

ol

o _{clockwise closing direciion os}

rn heolthy subiectsl l.

Other

ospecis chorocrerizìng re_ verse _{sequencing ore}

_o

_reduc:ion

in

speed

ond,

y.,hen

_kocings

_of

mondibulor

movemenis

_ore

mo-de

in the frontol

plone,

_{the rvidih}

of

the

_{trocing idisionce}

_behween

opening trocìng

ond

closing tro_

cing)

is smcller. Also, the rrocings

cross

over

eoch

other

_{the

cpe-ning

rocing

_{crossing the closìng}

irccing

_{(Figs ìo-dJ. Therefore. rhe_}

re ìs on onomolous

_ond

_{unbolon_}

ceC chew,ing potiern,

chorqcieri-zed

by

litle

voriob;lity ond

ex_

cessive repetltivens55 ì 2' I 5

Aim of

the

study

The oim _{of this study wos to onolr^}

ze ihe

mosiicofory pctiern

_of

_o

young

_{potieni',r,riih rìght unilcterol}

posierìor cross-bite, before thero py,

ihen

₆

_{monihs qfter correction with}

o _{funciicn generoiing biie, ond one} yeor ofter ccrreciicn.

Moieriols ond

methods

Clinicol

case

The ccse wcs thof cf on

Byeorold

girl

'wifi

posierior uniloierol

cross-b;-ie _{involving the following teeih:}

_53,

54,

55,

l6

ond

83,84,85,

46

Family medicol

histonJ

Absence

of

systemic or hereCiiory diseoses

obiectifs'

Evaluer

_la

direction

_de

_fermeture

_du

_cicle

_de

masticafion

_en

_un

_pofienr

_présentont

une

oc-clusion croisée

unilotérole

_{p,r,F,riuri",-"rr*}

traitemenr

avec

un

bite de

_{générateur de fonction}

_et

_six

mors

el

un

on

oprès

ovoir.corrigé

_lo

_{molocclusion.}

_{MaioJ"r-",t-*rteriou*.}

tJne

_fille

_{g-yeor-old ovec}

une

occlusion

_croisée

_unilatérale

_{a été}

trlaitée

_ovec

_uy,bi1e

_d"

_g6n5roÌrur

_de

fonction,

_qui

a

_corrigé

l'occlusion croisée en

5

mots.

l"r

rorur"

_nts

_{mandibuloires pendonl}

lo

maslication

_{d,un bol}

_mou

et d'un

bol

dur

étoient enregislré

ovant

_{et oprès}

_frolfemenr,

_enregis

tronf également

l,octivité

elec-tromyographique

_{du rnosseier ef des}

rnuscles

_{fernpore/s antérieurs.}

_Des

cycles

de

_{masticotoire ont élé}

enregisirés

_avec

_un

_kinesiograph

de

K6

!

_{Myotronic,

1r..,

i"oirt

e,

qA-IJSA).

_Résu/tois.

_Au

cam-mencemenf

_il

_y

_{avoit une prédominance}

marquée

_d",

"y./r,

oru,

un"

directionrenyersée

de la

fer-meture

(92%

pour,"

_o?):::

_.t,.e2%

_pou,r

_h

bot dur)

p;J;;,i;;rsffcoilon

_du

_còté

d,occrusion croi.

sée'

6

mois

oprès

que

la

correcti.on, p,endant

_lo

_{*rrtironlior-a,}

_,ari

l1rrigé,

le

pourcentage des cycles

ovec

la

fermefure

renversée

_o

_diminué

_o

_2%

_pour

_le

bol

mou ett

à

0%

pour

le

bol

dur.

Cefte

diminu-tion

étoit

encore

évidente

un

on

après

la

correctfon

_lo%

_pour

_le

_bol

_mou

_et

l

g%

pour

le

bo!

dur).

Lo

maslicafion

_du

_c6té

_sain

_{o à.tout}

moment

présenté

_{des cycles oru,}

_t,

_direcfion

normale

_de

fermetu-re'

Conclusions'

_{L'onalyse des}

_cycles

_de

mosticotoire

_enregisrrés

_{oyonr ei oprès}

_lo

fhéropie

ortho-dontique

_a

monlré

_qui

_étoit

_réalisée

_ron

_,"r/.ru

nt

une

"r'rr""rin

anatomique

avec

le

bite

de

gé-nérateur

de

foncfion'

_{mais égolemunt qru}

_to

_foncfion

a"

_{*ortirl,rtion ovoit regogné l,équilibre}

_et

la

symétrie

el

foufes _/es

_deux

_étoient

_sto6/es

ou

moins 1

an

oprès

_q,e

_recrossbib

_a

_{été corrigée.}

Cr,:":-biie anc cÀe,r,,lrg paìern

_I

Receni

and

remote

medical

history

The potieni

rvos

breosi-fed

for

6

months; she hod o\€rcome fhe

fpi-coi childhood diseoses.

No

diseose of ihe _{vertebrol column wos present}

Analysrs

_of

_occlusion

The potieni _{presented neutrol}

mo-lor

closs

ot

right qnC

left,

2

mm

overbìte,

₂

_{mm overiet}

qnd

unilo-;erol posierior _{cross-bil_. involving}

ihe following teeih:

_53,54,55,

_lÀ

ond

83,84,85,46

_iFigs

_2oc)

Lo

tero-l

ote r a

I

ce ph a I o m efri c

analysis

Cephclcmeiric

investigoiion inrcs

corried out _{by compcrotive} oncly-sis

follolving

Brccco

_etol.,

_rvhich utilizes

Cervero.

Sieiner

ond

Ric-keits kocings

for bosol

clossifico-iionl6.

Following Cervero, _ihe

co-se moy be clossified os

o

bosol Closs l, since

A

:

Po

₌

3

mm _in.rr.

=

2

r

3);

likewise fcllor^.,ing Ric-keits, since

A

: Npo

_{= 2}

mm (n.i,.

= 2

t

2)

ond

Steiner. since

ANB

òo ,

- Z illtt = / + )l

Follorving Schudy, the consiituiionol irTpe is _{meso-hyperd ;,;ergeni, since}

SpP^GoGn=26'(nv =2a=

5); likervise _{folloiving Sieiner slnce}

SN

a

6;o6n

=

36"

_{n.v

₌

321

ond Rickerts, since ANSXi

^

pM =

49'

{n.v.

= 45

t

3).

The Fronkfuri plone is postoriented, since SpP

_^

F

₌

0'

_{n

v

_{= 5}

t

_3).

The upper incisors ore pro-inclined,

since

I

I

_^

Oc =

53.

{n.v.

= 62

x.

4'),

ond _{the inferior inciscrs ere}

nor-moinclined, since

41

_^

_{Cc = 74"}

in.v.

=

/3

t

5').

The interìncisol

on-gle is

ì27"

ln.v.

=

135

r

5").

obietivos'

Evoluor

_{onies del iroiomiento}

_lo

_direcci6n

de

_{cierre duronte el}

_{ciclo de}

_mosticoci6n

en

un

pociente con

un cross-biie

_uniioterol

_Dosierior,

_con

un

"generoior

bite',

después

de

un

ofro

y

seis

m*

ses

de hober

_{corregido lo}

_moloclusi6n.

_Mot"riol",

y

*aila",

ìue

trotodo uno

nifro

de

g

ofros

con

un

cross-biie

_{poslerior uniloterol}

_derecho

utiliz;ndo ,n ;g"nuroto, bitJ",

que

corrigi6

el cross-bite en

5

me-ses' Los movimienios

_de

_{lo mondibulo}

duronte Io

moii.o.i6.

a"

,.

bolo

oiime-nrorl";;;;

y

de

un

bo

lo olimentorio duro fueron registrodos

ontes

y

después

del

tro;;*i"nto,

tombién

fue

registrondo

io

oc-tividod

electromyogrophic

_{de-i mosetero}

,

J:

,:r

mùsculos ternporoles

_onteriores.

_Lor

_li.lo,

_de

mosti-coci6n

fueron

regiskodos

co.n un

kinesiogroph,de

_K6l

_{(My"i;;rl;rìnc.,}

seonle,

wA-usA).

Resuliodos.

lniciolmenfe hubo

predominio

morcodo

i"li.b,

_du

_,orti.o.io,

".

r"

direccì6n opuesio de

cierre

(el

92%poro el

bolo

olimeniicio

suoye

y

_{elg2T"poro el uolo}

_{otin,"nticìo}

duroJ

fue observodo

₆

meses

después que

duronte

lo

mosiicoci6n

_{en el}

_lodo

_{del"rorr-bit"}

_J;

_{ì;:.rr"..i6n}

y duronte

lo

mosticoci6n

en

el lodo corregido;

_qY"^:l

_porcentoie

_J"

_.tr*

en

cierre

_ir"*tia"

_disminuy6

_{hosto el}

_2y"

poro el

bo

lo olimenticio

suove

y

el 0%

poro

"rioro

otìr"niicìo duro.

Esio

disminuci6n.sigui6

siendo

evidente

un

ofro después

_{de lo}

_correcciin

{el

0%

poro

ui

uoto

oli*"nticio

_srrr"

_y

"r

l

g%

_poro

el bolo

olimeniicio

duro)'

Lo mosticocién

_tn

_el

_loio

_{r".;-;r;;rt6;ù;;.oi.,}

i"".,"rre

en

ro

direcci6n

normor.

con-ciusiones'

_El

_on6lisis

_de

esle frotomiento onies.y

después

_ortodo..-io,

_{demostr6 gue en}

el

registro

de

los ciclos

_{de mosticoci6n,}

_{no s6ro fue}

_,*rr"r,o

ur'probi"*o

";;;.;

con er ,,generotor

_biie.,,

_{sino que}

o

su

vez

se _{recupero el}

_equilibrio

_{de lo}

_mosiicoci6n.

Ademds

lo

sinrekio

".

";;;;

fuJrJn

urroblu.

po,.

lo

menos después

_I

_ofro

_de

_que

_lo

_,ordilo

.rrrodo

fr"r*

."""g,ì"

5

Crcss-biie

_cnd

_{che,.+,in.q paÌtern}

P o ste ro-a nte ri o

r

ceph al o m elri c

analysis

The cnolysis

wcs

corrìed out

follo

i.ving ihe Turin Schooils. _{The oxoid}

relevont

io

ùe

inferlcr _{iovv shows}

clockivise _{rotoiion. iypicol}

_for

_righi un ilsiersl posterior _cross-bite.

Th era peuti

c

co n si deroti on s

To

correcl

the

molocclusion

o "Function

_Generoiing

_Bite"

[FGB]

wos used.

li

is on originol

op_

plionce chorocierlzed

_by

expon-sion _{springs, posterìor metoll;c}

bi_

te plones to

ovoid

_iniercuspol

con-tocis

ol

tlre reeih Curing

orlhodon-tìc

movements

_ond

_resin

polotol

ploie

for

tongue

reconCilio-ningì9,:o' it wos

irrorn

_doy

ond

night excepi

during

meols.

Cor-rection of ihe cross-bite rnros

ochie-ved

wiiliÌn

5

monrhs (F;gs 2d-i).

Experìmenfal protocol

Chewìng cycles vvere reccrded

be-fore

the

beginning

of

the

ortho-dontic theropy ond

repeoted

6

monlhs _{ond one yeor olier}

correc-tion of ihe cross-bÌie.

Mosticoiory cycles were recorded

wiih ihe

_{subiect cherving}

_o

_sofi

{chewing-gum)

ond

o

hord

{wine-gum) bolus;

o

Mvorronics

_K6]

ki-nesiogroph r.vos used tc record the mosticolory pohern. _The

exomino-tion

protocol entoiled

deiibercte cherving

on

the

righl,

then

on

ine

Iefi,

then free

chewirg.

Eoch mc-doliru*

rvos repeoted

three tjmes,

first

_wiih

the

sofi

bolus

cnd

:hen

with the hord bolus2ì.

The _{subjectwos ploced in on upright} secbC posiiion ond looked oi o poìnt

oboui

I

m in fronl otherz2.

Results

Before theropy,

ihe subiect _{chewing o soft bolus}

compleied

On

the _{righr {cross-biie) side:}

.

3

normol cycles (B%),

.

₃₃

_{reversed cycles (92?2");}

r

totol:

36

chewing cvcles.

Cn

ihe _{lefi {heolrhy}} siCe:

.

33

normol cycles _{BZ?,É);

r

₅

Te'.,ersed c.vcles

_{l

3i6);

r

totol:

38

chewìng cycles.

Chewing

o

hord bolus

she completed

On

rhe rìghi (crcss-birej sìCe:

o

3

ncrmol cycles _{8?é),

.

₃₅

_{reuersed cycles}

{92?É);

o

toiol:

38

cher,r,ing cycles.

Cn

ihe _{lefi iheolihy)} s;Ce:

'

38

normol qrcles _{l00?6);

I

0

reversed cycles;

.

toiol:

38

chewing cycles.

6 Months

ofter

correciion

chewing

_o

solt bolus

she compieled

Cn

-he righi _icorrectedJ sicie:

.

42

normol cycles _{gB?6J;

r

_l

_{reversed cycles i27.);}

.

toiol:

₄₃

_{chew,ìng g/cles.}

Cn

;he leh {heolthyJ side:

.

36

normol _{rycles {927.),}

r

3

reversed cvcles(B?2.);

.

totol:39

chewing cycles.

Chewing

o

hord

bolus

she completed

On

ihe _{right {correcied) side:}

.

45

normol cycles _IQZ%),

c

4

reveTsed cycles (B?z.J;

.

tolol: 4Q cherving cycles.

On

_{the lefi (heolrhy) side:}

.

48

rcrmol

_{cycles {l CO?:);}

.

no reversed cycles lO7)

r

iotol:

48

clrerving _9,/cles.

One yeor ofier correciion,

chewing

o

soft bolus

she completed

On

ihe _{right {ccrrected) side;}

.

42

normol cvcles (ìOO)7";

.

nc

Teversed cycles iO?6);

.

iotc,l..

42

_{cher^ring cycles.}

Cn

ihe _{lefr [heqlihi,) side:}

.

₄₀

_{normol cycles ilO0?,.);}

.

no _{reversed cycles {0ià),}

r

ioiol:

40

che'wing cycles.

Chewing

o

hord

bolus

she completed

Cn

ihe rìght _{icorrecied) side}

.

3

I

normol cycles _{82?6);

I

7

reversed cycies

(l

896);

.

Ìotol:38

chewlng cycles.

Cn

the _{left (heolthyJ side:}

.

₃₃

_{normol cycles}

{85?dJ;

.

6

reversed cycles {1 5?/.J;

.

iotol;39

chewing cycles.

In

figure

I

_fie

mosiicoiory poilern clreiving o hord bolus Ìs represented: Celiberote rnosticoiion

_cn

tlre

righl side _{(crossbite sideJ io) oncj on tlre left}

side

(bJ _{before theropy; deliberqte} moslicoiion on the rìght _side

{correc-ied _{side) ic) onC on rhe left sìde}

{d)

ofter theropi,. The green ond fhe red

line represent respeciii,ely the

op*

ning

ond

the closing cher^uìng

pot-Ce:ss-biie rrrd cfiev,,:lg naie:n Ò

F;gs

lo-d

A"Aosticotorv, ootiern che. '.,r,ìng

o

_{hc,o' bolus: deiicerore mcrstì.} cction cn the righi side _{{cross-bite side)}

ioJ onC on tne ieft side (bl beiore the.

rooy; _{deiicerote mosficoiion on tne}

right side _{(cor.ected sicje) (c) ond cn} the leh sicie {d ofter thercpv

À/tosticotion _{on r.iqht sicie} Crosscile sicie

HorC bolus

Reverse cycle

iViosticoiion on left sicle

Heolrhy s;de Hcrd bolus

Non rei.erse cycie

before

oftei

iern. The resulis ore illustroted in the histogroms {Figs

3oc,

4oc)

Discussion

The

resulis

show

thot

befor,^ the

subleci

wos

treoted, lhere

_{wos c}

morked prevolence

_of

reverse

se-quencing _192%

_of

_reverse

sequen-cing] when che,r,ing eiiher o sofr or

o

horC bolus

on

fie

molocclusion

side

When cherving

on

ihe

heolihy

side,

_{fiere wcs}

_o

predo-minonce

of

normol

sequencing

iB7%

ol

normol sequencing for the soft bolus

cnd

I OO7É for rhe hord

bolus). After cross

biie

correction

r,,uith the funciionol

opplionce,

ihe

remsr-7

Crox-btie cnd chew,inE pcitert:

Figs

2o-i

Introorol

,ieit':

before theropy _{{o-c), during theropy}

{c-fl, ofter correciion _{g-i).

kobly reduced

io

2% of reverse se-quencing with the soft bolus, Oià of

reverse sequencing ,.t,ìth

the

hord bolus. This _{result remoined stoble ot}

leost

I

efier ihe cross bite

wcs

cor-rected {no reverse sequencìng wiih the soft

bolus,

lBTo

of

reverse

sa

quencing

wiih

the hord bolusJ. The chewing pottern is esioblished

by

fie

cenirol nervous system ond

ihen

_{mqinfoined through rhythmic}

ociivirrl by rhe ouiomoiìc ceniers

ol

ihe brcìnsiem {rhythmic poiiern ge-nerotorJ. lt is _{olso moduloted bv} qf_ ferent infcrmolion _{lrom the orol}

cc-vìfy23. The presence _{of o cross-bite} deiermines _{the progromrning}

_,:f

cr

poriiculor chew.ing potiern knornrn

os

"reverse chewing

pcttern,,,

which encbles lorger

cusp

surfo-ces to be opposedi3.

As noied

previously

_{ìn ihe}

intro-duciion, unilobrol posierìor

cross-bi-le is

o

molocclusion chorocterized

iron-C,'oss'òiie _{onc cievi,irgl i--oterrr 8}

i

Figs 3o-c Percenioge _{of re,,,erse chewing cvcles che,.t,ing}

o soft bculs.

OIO _OF

REVERSE GHEWING CYCLES CHEWING A SOFT EOLUS BEFORE

THERAPY

E % OF REVER CYCLES

by

reverse

chewing

cycles

on

ihe cross-biie side

ond

ii frequenily

of-fecis children

in

eorly

ch;ldhoco.

tvhen ihe

principol

moi.or schemes

ore

obcuÌ

to be estobl:sheC. From _{the Cenlol slcndpolnt,} cross-bi-le con eosìly be correcied wirh

dit

ferent types

of

orihodoniic

op-plionces. Rother thon simple ono-tomiccrl correction, neuro-musculcr

ond

funciicnol correc;ion

is,

no-wcdoys, considered lo be of

greo-ier impcrtongs:24-2c.

Although

it

is

oi

primor.v

impor-tcnce

for ihe

fuiure heolth

of

the

sfomoiognolhic

srlstem,

re-esio-blishmeni of functionol equilibrium.

n,hich should iollow. onciomicoi

correciion, is very Cifficult tc .ochiel,i a<

-ver4

i'r.

_{For exomple,} Throckmcr-tcn ei

cl.

found thot

in

ì

5

pofienis

y'ilh

_unilcterol

_posterior

_crcss

bi-ies, il-re Teverse sequencing

recoi.-ded

cn

ihe

crcss

bile side

r^;os

siill

presenr

ofter

ropior

mcxillory

exponsion

_wos

_performeC

_tc

cor-reci ihe

cross

bÌieslj.

Sim,lorl;2,

Brin

_{ei ol}

correcied

the posterior

uniloterol cross biles in

24

potienis

ond observed thoi ihe inhereni

pol-lern

_{of ioiv}

movemeni

diC

"not

chonge

signÌfìconil',i

with

crrho-doniic

treoiment"25.

ln ihe preser-,i cose repcrt, the

elec-trognothogrophic pre ir-eoimerrt,

6

months

ond

ì

yeor

posi treoimeni

evcluoiicns demonsircied

ihci

ihe

function _{generoiing biie} is

copoble

of

correciing

ihe

ìntercuspcl

relo-tion,

of

normolizing ihe

chewing

cycles ond

of

reinstolrng ihe equili-brium of tire neuromusculor sysiem.

However, os discussed,

ihe

bene-ficiol _{result noieC in}

_fiis

_{pctieni moy}

7" _{OF RÉVERSE CHEWING CYCLES} CHEW'NG A SOFT B{)LUS 6 MONTHS AFTER

coRReclil....-B OÀ _{OF REVERS}

CYCLE

% OF REVERSE C'IEI'{ING CYCLES CHEWN§ A §ON

BOLUS 1 YEAR AFTER COFRTCTION

f:

RIGHTSIDE LEFTSIDE

I

Coss-b,ie ond cÀe,r.,inE

po#err,-no; be

o

usuol flnding sìnce ihe

re-sioroiion of

q

normcl chew,ìng por_

tern

on

ihe

_{cross bìte}

_{side is}

_{Cis_}

iìnctly uncommcn ofier

fie

cross bi_

te:s

cs11s61olìa,25

The Iunciìon generoting b;re is the

refore c vclid _{the,opeutìc tool ln cor_}

recling crossbife, _{especiolly during}

childhood,

becclrse

ii

correcis

_fie

molocclusion

_ond

_the

_mosiicoiory

funciion,

while

_{respecting the}

gno-thoiogic ond neurol componenis.

Conciusions

Pcsierior cross-bite !s

o

molocclu-sion thot

involves

_{noi only}

_deniol

molposifion but olso bosol.

neuro-musculor qnd _{functionol olterofions.}

ln

ihis cose

repcri.

there .wos _o

high

percenrcge

_of

_reverse

che-wing

sequencing

present ,,nrhen

chewing _{on the cross-bite siCe.}

The-re wos

o

remorkoble decreose of

reverse

chewing

sequencing

_oi

6

months

ond

_{one yeor ofier}

ccrrec-tion of ihe

cross-bìte.

Elecirogno-thcgrophy is the mosi oppropriote

technique

tc

monÌlcr Ìmprovemenis in mosiicotory funciion. Norvcdoys the correctìon

_of

_{cross-blte shouid} noi onlv reesioblish

_o

_normol

den-tol relotionship but olsc o functionol

equilibrium

_of

_the

_{siomorognoihic}

sysiem.

Figs

4o-c

Percenioge _{of revei.se cherving cvcles chewing}

o rord bouls

% OF REVER5E _{CHEWIilG CYCLE§ CHEI'UII*G A} HARD BOLU§.BEFORE THERAPY

li.-%€FrE-/EF-"ecyc,§§l

% OF RE\IERSE CI{EWNG CYCLES CHEWNG A

HARD BOLUS 6 I'ONTH§ AFTER CORRECTION

RIGHI

SDE

_UFISIDE %OFR§/ERSEDCHE$flNG _{CYGLES CHEWING A}

HARD EOLUS YEARAFIEì CCIRRECTr)N

bj

i , i

ii

jj