Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8. C anio acial asymme y
e494
Jou nal sec ion: O al Su ge y doi:10.4317/medo al.15.e494
Publica ion Types: Re iew
Diagnos ic o c anio acial asymme y. Li e a u e e iew
Rosa-Ma ía Yáñez-Vico 1, Alejand o Iglesias-Lina es 2, Daniel To es-Laga es 3, José-Luis Gu ié ez-Pé ez 4,
En ique Solano-Reina 5
1 Resea ch Schola ship. S oma ology Depa men . P o eso o he O hodon ics and Den o acial O hopeadics Mas e . School
o Den is y. Uni e si y o Se ille
2 P o eso o he O hodon ics and Den o acial O hopeadics Mas e . School o Den is y. Uni e si y o Se ille
3 P o eso o O al su ge y. S oma ology Depa men . Uni e si y o Se ille
4 Chai main o O al su ge y. S oma ology Depa men . Uni e si y o Se ille. Che o UGC in O al and Maxillo acial Su ge y.
HU Vi gen del Rocío. Se ille
5 Chai man o O hodon ics. S oma ology Depa men . Uni e si y o Se ille
Co espondence:
HU Vi gen del Rocío
School o Den is y o Se ille
C/ A icena s/n 41009
Se ille. Spain
daniel [email protected]
Recei ed: 22/03/2009
Accep ed: 28/11/2009
Abs ac
Facial asymme y is a common ea u e in many synd omes, and equi es su ge y as he only alid ea men
op ion. Rou ine diagnos ic me hods ( on al RX, pano amic RX and submen o e ex RX) ha e se ious limi a-
ions mainly due o he ans e om a h ee dimensional image o a wo dimensional plane. The easibili y o
such me hods is poo ly suppo ed due o inhe en p ojec ion e o s (image magni ica ion, c anial o a ion) and
iden i ica ion e o s (image quali y, p ecision and ep oducibili y). The use o compu e omog aphies ep esen s
a subs an ial imp o emen in he sense o skele al and so issue s uc u es’ ep oduc ion p ecision. The in e p e-
a ion o his new da a sou ce makes e iden he necessi y o new analysis ools o ex ac ion, manipula ion and
syn hesiza ion o he whole diagnos ic and he apeu ical po en ial based on mo e solid s udies in his ield.
Key wo ds: C anio- acial asymme y, x ay diagnosis, cephalome y, diagnos ic e o .
In oduc ion
Facial aes he ics has exponen ially inc eased i s im-
po ance in all heal h ields. As a consequence, pa ien
equi emen s and demands ha e g own in a pa allel
manne and equi e o cons an p o essional imp o e-
men s. Scien i ic li e a u e has shown a g ea connexion
be ween symme y and a ac ion in animals and also
in humans (1).
C anio acial asymme y is no only an aes he ic aspec
bu also a ea u e o pa hology due o inhe en symme y
on many skele al s uc u es. Addi ionally a subs an ial
numbe o dysmo phic synd omes a e ela ed o c anio-
acial anomalies and se e e acial asymme ies. S uc-
u e a iabili y, mal o ma i e ange, mal o ma i e ae i-
ology and indi idual eac ion a e cha ac e is ic ea u es
Yáñez-Vico RM, Iglesias-Lina es A, To es-Laga es D, Gu ié ez-Pé ez
JL, Solano-Reina E. Diagnos ic o c anio acial asymme y. Li e a u e e-
iew. Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8.
h p://www.medicinao al.com/medo al ee01/ 15i3/medo al 15i3p494.pd
A icle Numbe : 2764 h p://www.medicinao al.com/
© Medicina O al S. L. C.I.F. B 96689336 - pISSN 1698-4447 - eISSN: 1698-6946
eMail: [email p o ec ed]
Indexed in:
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Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8. C anio acial asymme y
e495
o hese mal o ma i e synd omes. Many o hogene ic
su ge y pa ien s ha e asymme ical acial cha ac e is-
ics a e he su gical p ocedu e and in many cases hey
only pay a en ion o hem a e he su ge y. The e o e,
a co ec diagnos ic is necessa y in o de o pe o m an
op imum and e icien he apeu ic app oach.
Vig e al. (2) e alua ed 63 on al adiog aphies o chil-
d en be ween 9-18 yea s o age o de e mine symme y
in di e en pa s o he ace. The child en didn´ show
clinical asymme ical cha ac e is ics. Su p isingly, a
majo i y o he child en showed a gene al asymme i-
cal pa e n. Acco ding o Vig e al. he le side o he
ace was he longes pa . The den oal eola egion
was he mos symme ical egion p obably caused by
compensa o y changes due o den oal eola de elop-
men ha allowed a symme ical mas ica o y unc ion
and a maximum in e cuspida ion. The bo de be ween
pa hological and no mal asymme y is no as clea as i
should be. Usually his concep is ela ed o he clini-
cal opinion and o he own pe cep ion o he pa ien .
Due o he signi ican imp o emen s ha ha e occu ed
in he ield o Medicine and In o ma ics, he majo i y
o he classi ica ions used nowadays o asymme y
o c anio acial de o mi ies ha e become obsole e. The
impo ance o speci ic c anial g ow h poin s mus be
highligh ed along wi h i s ole in hese conc e e mal-
o ma i e synd omes.
In sum, a diagnos ic e o in he c anio acial asymme y
due o a misin e p e a ion o a poo iden i ica ion o he
s uc u es implica ed on he asymme y could limi he
he apeu ical op ions leading o an e oneous ea men .
A e iew o he cu en li e a u e in he ield is p esen
in his a icle. This a icle, as well, compiles diagnos ic
ma e ial and me hods ou inely used o he diagnos ic
o he asymme y.
Pano amic Radiog aphy
Pano amic X- ay echnology is commonly accessible
and used in daily clinical ou ine. These adiog aphies
allow a bila e al iew and a e adequa e o in o m on
e ical measu emen s. This is he main eason o
using hem o asymme y e alua ion o he condyla
and he amus p ocess and o measu ing e ical di -
e ences be ween bo h sides. In his way Habe s e al.
(3) (Fig. 1), Sağlam e al. (4) (Fig. 2) me hods mus be
highligh ed among o he s.
Since he 80´s, di e en au ho s (5) ha e explo ed his
diagnos ic ool o measu ing amus and condyle e i-
cal di e ences. These au ho s conclude ha many de-
iciencies mus be he esul o he dis o ion and mag-
ni ica ion o he amus and he condyle. Addi ionally
he condyle s uc u e is equen ly supe imposed wi h
he la e al edge o he glenoid ossa and zygoma ic a ch
oo . Al hough pano amic x- ay echnology has an ac-
cep able cos -bene i a io due o he minimum adia ion
Fig. 1. Habe s e al me hod (1988). AC: condyla p ocess heigh ; AR:
mandibula amus heigh ; A: angen o he mandibula amus; B:
angen o he condyle and pe pendicula o A; O1 y O2: la e al poin s
o he condyle and mandibula amus, espec i ely.
Fig. 2. Saglam and San i me hod(2004). A: angen o he amus; B:
pe pendicula o A; CH condyla heigh : RH amus heigh ; O1 y O2
he mos la e al poin s.
Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8. C anio acial asymme y
e496
exposu e, he li e a u e doesn´ con e big us o meas-
u emen s done wi h his ype o p ojec ion. This me hod
is suscep ible o dis o ion and mo emen o he image
due o a igh image in he an e io a ea (6). The e a e
e en some au ho s such as Rams ad e al. (6) ha sup-
po he necessi y o a oiding any kind o measu emen
pe o med on pano amic adiog aphs.
Howe e , o he au ho s hink ha s anda d head po-
si ioning and bi en wax diminish he majo i y o dis-
o ions (4). Due o he nonlinea a ia ion ha occu s
by he di e en dep hs he e is no con o e sy on he
in alidi y o he ho izon al measu emen s. The e o e,
La heim e al. (7) hinks ha e ical and angula meas-
u emen s can be ep oduced i he pa ien is p o ided
wi h adequa e equipmen o head posi ioning. Recen ly
a sys ema ic e iew (8) has highligh ed once mo e he
poo easibili y o measu emen s pe o med on his
kind o x- ay and he high a iabili y depending on he
x- ay machine.
Pos e o /An e io Radiog aphy
Despi e he ac ha he pos e io adiog aphy has be-
come one o he mos common clinical x- ay p ojec-
ions o he diagnos ic o asymme y, i ’s gene ally
assumed in he li e a u e ha i is especially di icul
o pe o m alid measu emen s o such pu pose (9).
The e a e many s udies ha e alua e he alidi y o he
on al cephalome y (10,11). These s udies conclude
ha he e a e wo basic e o s in he pos e io /an e io
p ojec ions: hose ela ed o he cephalome ic me hod
(objec - ilm dis ance, head o a ion) and hose inhe en
o he me hod ( e e ence poin s localiza ion, iden i i-
ca ion e e ence poin s due o s uc u es adiolucency,
s uc u e supe imposi ions) (12).
Re e ing o he head posi ioning, a simple head o a ion
would be enough o dis u b he pe pendicula i y o he
c anial mediosagi al line o he x- ay beam leading o
dis o ed measu emen s. E en i ideal posi ioning we e
achie ed, he loca ion o a p ope mediosagi al axis in
hose pa ien s a ec ed o se e e asymme ies s ill be-
comes especially complica ed. Fu he mo e, we o en
conside a p ope pe pendicula posi ioning o he con-
nec ion axis o be be ween bo h ex e nal audi o y holes
and he mediosagi al line, which is usually comple ely
inaccu a e. The e o e, asymme ic ea s would p o oque
a head o a ion and he e o e a misin e p e a ion o he
asymme y (13).
Usually cephalome ic e o s ex ac ed om he p ojec-
ion o a h ee dimensional head in a wo dimension-
al x- ay ilm a e no aken in o accoun . Acco dingly,
Chidiac e al. (13) e alua ed hose e o s. The a e o
cephalome ic dis o ion dec eases g adually he close
he s uc u es a e o he x- ay ilm. I also di e s de-
pending on di e en planes; mandibula wid h (de ined
as he dis ance be ween igh an egonial and le an e-
gonial: AG-GA, being an egonial –AG– he mediales
poin in he an egonial no ch o he mandible) was a al-
ue o 4,42% and he maxila wid h ( igh jugal –le ju-
gal: JL-JR, being jugal–J– he mos in e io poin o he
zygoma ic-al eola c es ) was a alue o 1,83%, i he
ilm was si ua ed 13cm away o he anspo ionic axis
(line ha connec s bo h ex e nal audi o y holes). This
ac sugges s ha he diagnos ic o he di e ence be-
ween he maxila and he mandibula wid h inc eases
he AG-GA alue di e ence by app oxima ely 2,5%.
Conce ning he p ecision in he loca ion o he e e ence
poin s, di e en au ho s (13,14) ag ee on he necessi y o
using he e e ence poin s wi h a a ia ion o less han
1,5mm o he cephalome ic analyses. Mayo e al. (14)
ou lined 2mm as he e ical localiza ion e o o he
poin C (Galli C es : he supe io poin o he galli c es
o he e hmoidal bone). The li e a u e (14) ecommends
a c i ical posi ion on he alida ion o he maxila and
mandibula wid h.
The J poin expe iences a a ia ion o 2,60mm in a
ho izon al di ec ion and 3,06mm in a e ical di ec ion.
Howe e , usually in he clinical p ac ice, he ans e -
sal analysis is limi ed o he di e ence in be ween bo h
jaws, wha se iously limi s he ea men op ions and he
ea men planning.
Submen o e ex P ojec ion
This kind o p ojec ion is mo e use ul han he o he wo
ci ed due o he excellen isualiza ion o he c anial base
s uc u es ha allow he use o he ana omical e e ence
poin s o e he c anial base o de e mine he mediosag-
i al axis. Despi e i s inhe en bene i s, i ’s used much less
in he clinical p ac ice han hose desc ibed abo e.
Be ge was he i s au ho ha suppo ed he use ulness
o he submen o e ex p ojec ion (SMV) o he e alu-
a ion o asymme y in cephalome y. Gilbe in es i-
ga ed he p ecision o his kind o p ojec ion wi h a ilm
o ien a ed pa allel o he ho izon al plane o F ank o .
The wid h ac o s we e ound highly ep oducible. Ne -
e heless, signi ican longi udinal measu emen e o s
we e ound. This au ho didn´ sugges any de ini i e
cephalome ic analyses. Ri ucci and Bu ns one used
e e ence poin s on he c anial base and hey de eloped
a cephalome ic analysis o he e alua ion o he asym-
me y on he c anio acial complex. Howe e , Fo esbe g
e al in 1984 (Fig. 3) and G ayson e al in 1985 we e he
i s au ho s o publish a me hod o he e alua ion SMV
x- ays using a mul i-planning skele al acing analyses
on he c anial base, mid ace and lowe pa o he ace.
This me hod allowed he calcula ion o asymme y on
he c anial base, he zygoma ic complex and he mandi-
ble. All e e ence poin s calcula ed ela ed o a coo di-
na e sys em om he spinous o amen, he mos s able
and ep oducible poin in he c anial base.
Williamson e al. (15) s udied he iden i ica ion e o s
Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8. C anio acial asymme y
e497
in SMV x- ay. The mos signi ican disc epancy was
ound in he pogonion (Pg: he mos an e io poin on
he mandible in he medial sagi al plane o he mandibu-
la symphysis), up o 3,79 mm. Addi ionally, a endency
o supe imposi ion o he in e nal and he ex e nal co -
icals o he on al and he den i ion o e he an e io
egion o he mandibula symphysis was ound. This
supe imposi ion is subs an ially in luenced by head
posi ioning. Lysell e al. (16) sugges ed ha he p ojec-
ion e ec s would be minimal i he mandibula angle
we e p ojec ed immedia ely be o e o he condyle. The
ideal posi ioning o he head o he SMV adiog aphies
would be ha in which he X- ay beam is pe pendicula
o he F ank o plane; howe e , se e al limi a ions ex-
is in pa ien s wi h educed mobili y o he neck. The
in a and in e examina o e o s we e o low eliabili y
in he condyla poles, especially in he e ical di ec-
ion and in he pos e io condyla poin o he ho izon al
di ec ion. Rela ed o ha ac , he au ho s sugges being
cau ious in he in e p e a ion and use o he measu e-
men s ha in ol e such poin s due o he high numbe
o e o s emp ed wi h his me hod.
F om he wo o he h ee dimensions: The com-
pu e ized omog aphy
The a i al o he digi al image o he den al wo ld has
p o oked new esea ch ields ocused on he diagnos ic
po en ial o he adiog aphy h ough image manipula-
ion. Many o hose p oposals ha e esul ed in aluable
ools ha inc ease he diagnos ic u ili y. Howe e many
digi al images su e om limi a ions simila o hose
de i ed om he con en ional cephalome ic analyses
including magni ica ion, dis o ion and supe imposi-
ion o ana omical s uc u es.
Wi h he a i al o he compu e ized omog aphy he o-
ali y o he c anio acial complex can be analyzed wi h
high p ecision. The p omo e s o compu e ized omog-
aphy (CT) we e Co mack and Houns ield du ing he
60´s-70´s. These au ho s we e gi en he Nobel P ize o
Medicine. This echnology has p omo ed new ools o
medical esea ch and has become one o he mos ex-
ensi e in he image diagnos ic me hods nowadays. The
CT has p opo ioned he capaci y o isualize speci ic
issues in se e al sequen ial planes wi hou he p oblem
o supe imposi ion. I is a ac ha he compu e ized o-
mog aphy has become es ablished simul aneously wi h
he imp o emen o he scanne s used.
An impo an ad ancemen in he CT echnology has
come hanks o He man and Liu. In 1977 hese au ho s
in oduced h ee dimensional econs uc ions om ax-
ial slides. This me hod did away wi h he necessi y o
men al assimila ion o h ee dimensional images om
wo dimensional da a ( hose om con en ional x- ay
machines and om axial CT scanne s), which is o en
inaccu a e o impossible.
The CT allows us an exac de e mina ion o he ana omi-
cal s uc u es in h ee dimensions, hus p o iding us wi h
an imp o emen in he p epa a o y planning o many su -
gical p ocedu es (17). The CT allows o he isualiza-
ion o bo h he so issues and he skele al s uc u es in
3D. The majo i y o he li e a u e demons a es he high
p ecision o he CT-3D images (18). Mo eo e , he e is no
supe imposi ion o ana omical s uc u es and an absolu e
accu a e posi ion o he ana omical e e ence poin s can
be ob ained om all angles. Un o una ely, he e ec i e
dose ha is p o ided by a CT medical scanne is highe
han ha ob ained om he con en ional x- ay. Fu he -
mo e, he CT is ela i ely mo e expensi e and he scan-
ne s a e no easily accessible.
A new gene a ion o compac CT scanne s has been de-
eloped, specially designed o use in he head and neck
egion. Those especially compac CT scanne s use he
cone beam geome y (cone beam - CBCT) ha allows
o a high e iciency in uses wi h x- ay pho ons. The
dose p o ided by he CBCT is ela i ely low and e en
lowe han ha ecei ed by a pe iapical comple e se ies
and 100 imes lowe han ha gi en by a medical CT
scanne . The econs uc ion o he CBCT o e s a b oad
ield o ision (22-30cm), allowing he econs uc ion
and h ee dimensional isualiza ion o he maxillo acial
s uc u es. Addi ionally, con en ional images as pano-
amic, la e al and an e io /pos e io adiog aphs can be
ob ained om hose CBCT.
The subs i u ion o he con en ional x- ay machines by
Fig. 3. Fo esbe g e al me hod (1984). A: angula ; BC: bucal; MCF:
medial c anial osse; ZA: zygoma ic a ch; V: ome ; C: condyle; Go:
gonion; FS: spinous o amen; Ba: basion; Op: opis ion.
Med O al Pa ol O al Ci Bucal. 2010 May 1;15 (3):e494-8. C anio acial asymme y
e498
he CBCT o he s udy o he c anio acial s uc u es is
a po en ial ad ancemen in he ea men and diagnosis
o he wide ange o o hodon ic and o hogene ic pa-
ien s (19). The CBCT allows o he educ ion o many
limi a ions ex ac ed om con en ional adiog aphies.
Ne e heless, h ee dimensional images mean new
changes and he need o a new in e p e a ion om ha
which we a e used o o ex ac ing he mos in o ma-
ion possible.
Many echniques ha e been used in he CT econs uc ion
o he diagnos ic, plani ica ion and simula ion o he
ea men . Howe e , many changes on he supe imposi-
ion o images a e now appea ing o he moni o ing o
changes ela ed o he ea men o he s uc u es. Th ee
dimensional e e ence poin iden i ica ion equi es new
unc ional de ini ions sui able o he h ee dimensions
o space (20). The uses o a p ecise and consis en in-
s umen o he analysis o a wide ange o images ob-
ained om his kind o echnology, se s ou new diag-
nos ic possibili ies o medical p ac i ione s.
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