Arnett-Facial Keys to Orthodontic Diagnosis II

7/27/2019 Arnett-Facial Keys to Orthodontic Diagnosis II

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396 Arnett and Bergman American Journal o f Orthodontics and Dentofacial OrthopedicsM ay 1993

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Fig. 1. Facial height: Hair l ine (H ) to soft t issue menton (Me ' ) . .Facial widths: Zygomatic arch (ZA) to zygomatic arch (ZA) , .Gon i on (Go ' ) to gonion (Go ' ) .m a l e s . A n a l t e r n a t iv e t o m e a s u r i n g h e i g h t a n d w i dt iJ i st o a r t i s t ic a l l y d e s c r i b e t h e f a c e . F a c e s a r e w i d e o r n a r -r o w , s h o r t o r l o n g , r o u n d o r o v a l , s q u a r e o r r e c t a n g u l a r .

T h e i m p o r t a n t q u e s t i o n w h e n a s s e s s i n g t h e s e d i -m e n s i o n s i s: W i l l o rt h o d o n t i c a n d / o r s u r g i c a l c a re n e c -e s s a r y f o r b i t e c o r r e c t i o n c o r r e c t o r a c c e n t u a t e e x i s t i n gh e i g h t a n d w i d t h i m b a l a n c e ? A n e x a m p l e o f o r th o d o n t i cc o r r e c t i o n o f h e i g h t - w i d t h i m b a l a n c e i s th e u s e o f b i teo p e n i n g m e c h a n i c s t o l e n g t h e n t h e f a c e d u r i n g b i t e c o r -r e c t i o ~ A n e x a m p l e o f s u rg i c a l c o rr e c ti o n i s m a x i l l a r yi m p a c t i o n t o s h o r t e n t h e l o n g f a c e .

T h e e x t r e m e s o f d i s p r o p o r t i o n a r e s h o r t a n d w i d eo r l o n g a n d n a r r o w . S h o r t , s q u a r e f a c i a l o u t l i n e s a r ei n d i c a t i v e o f d e e p b i t e C l a s s I I m a l o c c l u s i o n , v e r t i c a lm a x i l l a r y d e f i c i e n c y , a n d i n s o m e c a s e s , m a s s e t e r ich y p e r p l a s i a . L o n g , n a r r o w f a c e s a r e a s s o c i a t e d w i t hv e r t i c a l m a x i l l a r y e x c e s s o r m a n d i b u l a r p r o t r u s i o n w i t hd e n t a l i n t e r f e r e n c e s l e a d i n g t o o p e n b i t e . T h e b i z y g o -m a t i c d i m e n s i o n i s o f t e n d e f i c i e n t ( c h e e k b o n e d e f i -c i e n c y ) i n c o m b i n a t i o n w i t h m a x i l l a r y r e t r u s i o n . T h eb i g o n i a l d i m e n s i o n m a y b e d e f i c i e n t i n c o m b i n a t i o nw i t h m a n d i b u l a r r e t r u s i o n .

H e i g h t a n d w i d t h d i s p r o p o r t i o n i s c o r r e c t e d i n t w ow a y s :

1.

.

M a x i l l a r y o r m a n d i b u l a r s u r g e r y i s u s e d s i m u l -t a n e o u s l y t o c o r r e c t t h e b i t e a n d t o l e n g t h e n o rshor ten the f ac ia l he igh t . " ' -A u g m e n t a t i o n o r r e d u c t i o n o f t h e f a c i a l h e i g h to r w i d t h .

)

L I ) d t

9 C I L

Fig. 2. Pupi l p lane (PP ) is horizo ntal line drawn through pupi ls.This l ine is usua l ly par al le l to the horizon an d is referred to a sfrontal postural horizontal. Upper dental arch (UDA ) level is al ine forme d through th e left and r ight ma xi l larycan ine ips. Lowerdental arch ( LDA ) level is a l ine formed through the left andright mand ibular canin e t ips. Chin-jaw l ine (CJL ) is assessedby a l i ne drawn on the under sur face o f the ch in a t max im umi issue contact. Al l four l ines should be pa ral le l to ea ch ether.

E x a m p l e s o f t h e l a t t e r a r e c h i n l e n g t h e n i n g t o i n -c r e a s e f a c i a l h e i g h t ( H t o M e ' ) , c h e e k b o n e a u g m e n -t a t i o n t o i n c r e a s e t h e b i z y g o m a t i c w i d t h ( Z y t o Z y ) , o ra u g m e n t a t i o n o f t h e m a n d i b u l a r a n g l e s t o i n c r e a s e t h eb i g o n i a l d i m e n s i o n ( G o ' t o G o ' ) . B u c c a l l i p e c t o m i e sc a n h e l p r e d u c e e x c e s s i v e w i d t h i n t h e s u b m a l a r c h e e ka r eas .

A s a g e n e r a l r u l e , t h e m a x i l l a s h o u l d r a r e l y b em o v e d u p a n d b a c k . T h i s m o v e m e n t d e c re a s e s l ip s u p -p o r t , i n c r e a s e s t h e n a s o l a b i a l f o l d s , d e c r e a s e s i n c i s o re x p o s u r e , a n d c a n m a k e t h e f a c i a l o u t l i n e a p p e a r s h o rta n d w i d e . T h e s e c h a n g e s g i v e t h e a p p e a r a n c e o f p r e -m a t u r e f a c i a l a g i n g .

T h e m o s t c o m m o n t o l e a s t c o m m o n s i t e s o f f a c i a la s y m m e t r y a r e c h in , m a n d i b u l a r a n g l e s, a n d c h e e k ~b o n e s . T h e m a x i l l a i s r a r e l y i n s k e l e t a l a s y m m e t r y .A s y m m e t r i e s c a n o c c u r w i t h a n y g r o w t h a b n o r m a l i t yb u t a r e s t r o n g l y a s s o c i a t e d w i t h u n i la t e ra l c o n d y l a r h y -p e r p l a s i a .

C o r r e c t i o n o f a s y m m e t r i e s a r e a c c o m p l i s h e d w i t h( 1 ) c a n t c o r r e c t i o n o r m i d l i n e m o v e m e n t o f th e m a x i l l aa n d m a n d i b l e s i m u l t a n e o u s w i t h o c c l u s a l c o r r e c t i o n o r( 2 ) a u g m e n t a t i o n d r r e d u c t i o n o f th e s k e l e t a l s u r fa c e s .E x a m p l e s o f t h e l at t e r in c l u d e u n i l a t er a l c h e e k b o n e ,


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American Journal o f Orthodontics and Dentofacial Orthopedics A r n e l t a n d Berg/nan 397Volume 103. No. 5

Fig. 3. Constructed horizontal reference ine is formed by draw -ing l ine through pupi l ar ea para l le l to f loor. This l ine is usedwh en the pupi l p lane is not pa ral le l to the f loor (eyes are no tlevel) wh en th e he ad is in frontal postural horizontal.

a n g l e , o r b o d y a u g m e n t a t i o n . A c o m m o n a s y m m e t r ycor rec t ion i s ch in sh i f t ing to the r igh t o r l e f t to cen te rt h e c h i n o n t h e f a c i a l m i d l i n e .F a c i a l l e v e l ( F i g . 2 )

T o e x a m i n e f a c i a l l e ve l s a r e l i a b l e h o r i z o n t a l l a n d -m a r k l ine i s neces sa ry . Wi th the pa t i en t in na tu ra l headp o s t u r e , 3 t h e p u p i l s a r e a s s e s s e d f o r l e v e l w i t h t h e h o -r i z o n . I f t h e p u p i l s a r e l e v e l , t h e y a r e u s e d a s t h e h o r -i z o n t a l r e f e r e n c e l i n e a n d a d j a c e n t s t r u c t u r e s a r e m e a -s u r e d r e l a t i v e to t h is l i n e ( F i g . 2 ) . S t r u c t u r es c o m p a r e dw i t h t h e p u p i l l i n e a r e ( 1 ) u p p e r c a n i n e l e v e l , ( 2 ) l o w e rc a n i n e l e v e l , a n d ( 3 ) c h i n a n d j a w l e v e l .

M a n d i b u l a r d e v i a t i o n s c o m m o n l y h a v e u p p e r a n dl o w e r o c c l u s a l c a n t s w i t h c h i n a n d j a w l i n e c a n t i n ga s s o c i a t e d . D e v i a t i o n s f r o m l e v e l s h o u l d b e n o t e d a n dc o r r e c t i o n i n t e g r a t e d i n t o t h e o v e r a l l b i t e t r e a t m e n tp l a n . I f b i m a x i l l a r y s u r g e r y i s c o n t e m p l a t e d , o c c l u s a lc a n t i s c o r r e c t e d r o u t i n e l y a t s u r g e r y . I f o n e j a w s u r g e r yi s c o n t e m p l a t e d , t h e o c c l u s a l c a n t c a n b e n e g l e c t e du n l e s s it i s e s t h e t ic a l l y p r o b l e m a t i c . W h e n p r o b l e m a t i c ,e i t h e r o r t h o d o n t i c t o o t h m o v e m e n t o r b i m a x i l l a r y s u r -g e r y m u s t b e u s e d t o c o r r e c t t h e c a n t .

I f t h e p u p i l s , i n n a t u ra l h e a d p o s t u r e , a r e n o t l e v e lt o th e h o r i z o n , a c o n s t r u c t e d f r o n t a l h o r iz o n t a l r e f e r e n c el ine i s used (F ig . 3 ) . Th i s l ine i s v i sua l i zed a s fo l lows :

I . F r o n t a l n a t u r a l h e a d p o s t u r e .

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F i g . 4. Im portant midl ine structures ar e assessed. Nasal bridge( N B ) , nasal t ip ( N T ) , filtrurrt ( F ) , upper incisor midl ine ( U I M ) ,lower incisor m idl ine ( L I M ) , and ch in mid l ine po in t ( M e ' ) shouldbe on a l ine that is perpe ndicular to the frontal postural hori -zontal. Fi ltrum is usua l ly the leas t asymmetric of the se pointsand is there fore genera l ly used a s a start ing p oint for midl inestructure assessment. Al l midl ine points may not l ine up. Thedenta l midl ines and chin should be place d to integrate wi th othermidlines (most importantly the fi l trum center).

2 . H o r i z o n t a l l i n e p a r a l l e l t o t h e h o r i z o n t h r o u g hthe pup i l a rea .

3 . Asses s o the r s t ruc tu res re la t ive to th i s l ine( F i g . 3 ) .

M i d l i n e a l i g n m e n t s ( F ig . 4 )M i d l i n e s a r e a s s e s s e d w i t h u p p e r m o s t c o n d y l e p o -

s i t ion and f i r s t too th con tac t . I f occ lusa i s l ides a l t e rj o i n t p o s i t i o n , n o r e l i a b l e m i d l i n e a s s e s s m e n t c a n b em a d e . T h e r e l a t i v e p o s i t i o n s o f s o f t t i s s u e l a n d m a r k s(nasa l b r idge , nasa l t ip , f i l t rum , ch in po in t ) and den ta lm i d l i n e l a n d m a r k s ( u p p e r i n c i s o r m i d l i n e , l o w e r i n c i s o rm i d l i n e ) a r e n o t e d . N e e d e d c h a n g e s a r e i n c o r p o r a t e di n t o th e s u r g i c a l / o r t h o d o n t i c t r e a t m e n t p l a n t o p o s i ti o nt h e s e s t r u c tu r e s o n t h e v e r t i c a l m i d l i n e o f t h e f a c e .F i l t r u m i s u s u a l l y a r e l i a b l e m i d l i n e ' s t r u c t u r e a n d c a nb e u s e d a s t h e b a s i s f o r m i d l i n e a s s e s s m e n t m o s t o f t e n .W h e n t h e p u p i l s a r e l e v e l i n n a t u r a l h e a d p o s t u r e , ave r t i ca l l ine th rough f i l t rum m idpoin t i s used to a s ses s

. . o t h e r h a r d a n d s o f t t i s s u e m i d l i n e s t r u c t u r e s ( F i g . 4 ) .I f the pup i l s a re no t l eve l , a ve r t i ca l l ine th roug h f i l t rumm i d p o i n t , p e r p e n d i c u l a r t o p o s t u r a l h o r i z o n t a l , i s u s e dt o a s s e s s m i d l i n e s t r u c t u r e s ( F i g . 5 ) . W i t h t h e e v a l u -


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3 9 8 Arnett a/zd Bergman American Journal o f Orthodontics and Dentofacial OrthopedicsMay 1993

ConstructedPosaa-alHorizontal

, . . 7I ] ] E ~ ,

F i g . 5 . W h e n p u p i l s a r e n o t l e v e l , c o n s t r u c t e d h o r i z o n t a l r e f -e r e n c e l i n e ( F i g . 3 ) i s u s e d . A p e r p e n d i c u l a r t o t h e c o n s t r u c t e dh o r i z o n t a l l i n e t h r o u g h f i l t r u m i s u s e d t o a s s e s s o t h e r m i d l i n es t r u c t u r e s .

1/3

, _ 7Middle 1/3

M e I

F i g . 6 . F a c e i s . d i v i d e d i n t o t h i r d s b y d r a w i n g l i n e s t h r o u g hh a i r l i n e (H) , m i d b r o w ( Mb ) , s u b n a s a l e (Sn) , a n d s o f t ti s s u e m e n -to n (Me ' ) .

a t i o n o f s k e l e t a l o r d e n t a l m i d l i n e s , e t i o l o g i c f a c t o rsa r e a s s i g n e d .

D e n t a l m i d l i n e s h i f t s a r e t h e r e s u l t o f m u l t i p l e d e n t a lf ac to r s inc lud ing :

1 . S paces2 . To oth r o ta t ions3 . M is s ing tee th4 . B u c c a l l y o r li n g u a l l y p o s i ti o n e d t e e t h5 . C r o w n s o r f i l l i n g s w h i c h c h a n g e t o o t h m a s s6 . C o n g e n i t a l t o o t h m a s s d i f f e r e n c e f r o m l e f t t o

r igh t

M o d e l e x a m i n a t i o n i s u s e d t o d i s t i n g u i s h d e n t a lm i d l i n e s h i f t e t io l o g i c f a c t o r s ( s p a c e s , r o t a t i o n s ) . D e n -t a l m i d l i n e s h i f t s a r e t r e a t e d o r t h o d o n t i c a l l y . A s y m -m e t r i c p r e m o l a r e x t r a c t i o n s m a y b e n e c e s s a r y t o a li g nden ta l and ske le ta l m id l ines . S ke le ta l m id l ine sh i f t s a r en o t c o r r e c t e d o r t h o d o n t i c a l l y , s u r g e r y i s e m p l o y e d .W h e n t h e d e n t a l a n d s k e l e t a l m i d l i n e s d e v i a t e t o g e t h e r,the e t io log ic f ac to r i s usua l ly ske le ta l , and sur ge r y i su s e d t o c o r r e c t ( i. e . , c h i n a n d l o w e r i n c i s o r m i d l i n e a r e3 m m to the l e f t ) . S tab i l i ty , pe r iodonta l hea l th , andf a c ia l b a l a n c e a r e o p t i m i z e d w h e n d e n t a l s h i f t s th e r e -su l t o f ske le ta l dev ia t ion a r e t r ea ted wi th sur g ica l , r a the r -t h a n o r t h o d o n t i c , t o o t h m o v e m e n t . A t t e m p t s t o o r t h -

o d o n t i c a l l y c o r r e c t t h e b i t e w h e n t h e e t i o lo g i c f a c t o r i ss k e l e t a l c a n p r o d u c e b u c c a l p l a t e v i o l a ti o n a n d g i n g i v a lrecess ion.4 '~F a c i a l o n e t h i r d s ( F ig . 6 )

T h e f a c e d i v i d e s v e r t i c a l l y i n t o t h ir d s f r o m h a i r li n et o m i d b r o w , m i d b r o w t o s u b n a s a l e , a n d s u b n a s a l e t os o f t t i s s u e m e n t o n ( F i g . 6 ) . T h e t h i r d s a r e w i t h i n ar a n g e o f 5 5 t o 6 5 m m , v e r t i c a l l y . ' T h e h a i r li n e i s v a r i -a b l e , a n d t h e u p p e r t h i r d i s f r e q u e n t l y l o w r a n g e . I n -c r e a s e d l o w e r o n e - th i r d h e i g h t i s f r e q u e n t l y f o u n d w i t hv e r t i c a l m a x i l l a r y e x c e s s a n d C l a s s I I I m a l o c c l u s i o n s( l a c k o f i n t e r d i g i t a t i o n o p e n s v e r t i c a l h e i g h t ) . D e -c r e a s e d l o w e r o n e - t h i r d h e i g h t i s a s s o c i a t e d w i t h v e r -t i c a l m a x i l l a r y d e f i c i e n c y a n d m a n d i b u l a r r e t r u s i o nd e e p b i t e s. P r o d u c t i o n o f c o r r e c t p r o p o r t io n i n f l u e n c e st h e c h o i c e o f s u r g i c a l p r o c e d u r e u s e d t o c o r r e c t t h eo c c l u s i o n ( i . e . , m a x i l l a r y i m p a c t i o n t o c o r r e c t C l a s s I Im a l o c c l u s i o n a s s o c i a t e d w i t h l o n g l o w e r o n e - t h i rdr a t h e r t h a n m a n d i b u l a r a d v a n c e m e n t ) . T h e e q u a l i t y o ft h e m i d d l e a n d t h e l o w e r t h i r d s s h o u l d n o t b e u s e d a st h e d e t e r m i n i n g f a c t o r i n f a c i a l h e i g h t c h a n g e s . T h ea p p e a r a n c e o f t h e l a n d m a r k s ( i n c i s o r e x p o s u r e , i n t e r -l a b i a l g a p ) w i t h i n t h e l o w e r t h i r d a r e m o r e i m p o r t a n ti n a s se s s i n g b a l a n c e t h a n a r e t h e e q u a l i t y o f t h e m i d d l ea n d t h e l o w e r t h i r d s .


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SQU p p e r L i p L e n g t h

F , . / Ii L o w e r L i p L e n g t hMe'

F i g . 7 . With l ips relaxe d, lowe r third is subdivided by drawingl ines thro ugh subnasale (Sn) , upp er l ip inferior (ULI ) , lowe r l ipsuper io r (LLS ) , and soft t issue menton (M e ' ) . The upper l i p ishal f the length of th e lower.L o w e r o n e - t h i r d e v a l u a t i o n ( F ig s . 7 t h r o u g h 9 )

T h i s a r e a o f fa c i a l a n a l y s i s i s e x t r e m e l y i m p o r t a n ti n s u r g i c a l o r t h o d o n t i c d i a g n o s i s a n d t r e a t m e n t p l a n -n i n g . T h e i m p o r t a n c e o f r e l a x e d l i p p o s i t i o n f o r th e s em e a s u r e m e n t s c a n n o t b e o v e r e m p h a s i z e d .

U p p e r a n d l o w e r l i p l e n g t h s ( F i g . 7 ) . T h e l i p s a r em e a s u r e d i n d e p e n d e n t l y i n a r e l a x e d p o s i t i o n ( F i g . 7 ) .T h e n o r m a l l e n g t h f r o m s u b n a s a l e t o u p p e r li p in f e r i o ri s 1 9 to 2 2 m m . x I f t h e u p p er l ip i s a n a to mica l ly sh o r t( 1 8 m m o r l e s s) , a n i n c r e a s e d i n t e r la b i a l g a p a n d i n c i s o re x p o s u r e i s se e n w i t h a n o r m a l l o w e r f a c e h e i g h t . T h i ss h o u l d n o t b e c o n f u s e d w i t h v e r t ic a l m a x i l l a r y e x c e s s( i n c r e a s e d i n t e r l ab i a l g a p , i n c r e a s e d u p p e r i n c i s o r e x -p o s u r e , i n c r e a s e d l o w e r o n e - t h i rd f a c i a l h e i g h t ) .

T h e l o w e r l ip is m e a s u r e d f r o m l o w e r l ip s u p e r i o rt o s o f t t i s s u e m e n t o n a n d n o r m a l l y m e a s u r e s i n a r a n g eo f 3 8 t o 4 4 m m . ~A n a t o m i c s h o r t l o w e r l ip i s s o m e t i m e sa s s o c i a t e d w i t h C l a s s I I m a l o c c l u s i o n a n d i s v e ri f i edb y c e p h a l o m e t r i c m e a s u r e m e n t o f t h e l o w e r a n t er i o rd e n t a l h e i g h t ( l o w e r i n c i s o r t i p t o h a r d t i g s u e m e n t o n ;w o m e n , 4 0 m m + 2 m m , a n d m e n , 4 4 m m - 2 m m ) .6A n a t o m i c s h o r t l o w e r l ip sh o u l d n o t b e c o n f u s e d w i t ha s h o rt l o w e r l i p s e c o n d a r y t o p o s t u r e ( u p p e r i n c i s o ri n t e r f e re n c e s ) s e e n i n C l a s s I I d e e p b i t e c a s e s w i t h n o r -m a l a n t e r i o r d e n t a l h e i g h t. A n a t o m i c s h o r t l o w e r l i pc a n b e l e n g t h e n e d w i t h a l e n g t h e n i n g g e n i o p l a s t y .

1 , % ._ . f . tU T T L

F i g . 8. Incisor expo sure is m easu red wi th l ips relaxe d fromupper l ip inferior ( U L I ) to m axi l lary incisor ed ge (M x l E ) . T heuppe r tooth to l ip (UTTL ) is the vert ical dimension of the incisorexposed be tw een U L I and Mx l E .A n a t o m i c l o n g l o w e r l i p c a n b e a s s o c i a t e d w i t h

C l a s s I I I m a l o c c l u s i o n s . T h i s s h o u l d b e v e r i fi e d w i t ht h e c e p h a l o m e t r i c a n t e r i o r d e n t a l h e i g h t m e a s u r e m e n t .A c l o s e d l i p p o s i t io n w i l l p r o d u c e a l o n g l o w e r l ip i nc o m b i n a t i o n w i t h i n c r e a s e d l o w e r f a c ia l h e i g h t ( v e r ti c a lm a x i l l a r y e x c e s s a n d C l a s s I I 1 ) a s t h e li p e lo n g a t e s t oc l o s e . T h e c l o s e d l i p le n g t h i s m i s l e a d i n g a n d s h o u l dn o t b e u s e d f o r t r e a t m e n t p l a n n i n g . T h e n o r m a l r a ti oo f u p p e r t o l o w e r l i p i s 1 : 2 . j P r o p o r t i o n a t e l ip s h a r -m o n i z e r e g a r d l e s s o f l e n g th ; d i s p r o p o r t i o n a t e l i p s m a yn e e d l e n g t h m o d i f i c a t io n t o a p p e a r i n b a l a n c e . L i p m e a -s u r e m e n t s i d e n t i f y n o r m a l o r a b n o r m a l s o f t t i s su e l e n g t ht h a t c a n b e r e l a t e d t o d e n t o s k e l e t a l l e n g t h n o r m a l c y ,e x c e s s , o r d e f ic i e n c y .

L i p r e d u n d a n c y i s se e n i n c a s e s o f v e r t ic a l m a x i l l a r yd e f i c i e n c y a n d m a n d i b u l a r r e t r u s i o n w i t h d e e p b i t e a n d ,r a r e l y , l o n g l i p l e n g t h s . T o a c c u r a t e l y a s s e s s l i p l e n g t h sw i t h r e d u n d a n t l i p s, t h e p a t i e n t ' s b i t e m u s t b e o p e n e du n t il t h e l i p s s e p a r a t e ( F i g s . 7 ) . ~ T h i s i s b e s t a c c o m -p l i s h e d w i t h a p in k b a s e p l a t e w a x b i t e u s e d to o p e nt h e b i t e o n c e n t r i c r e l a t i o n ( n o t r a n s l a t i o n ) , t T h e f a c ei s e x a m i n e d i n t h a t p o s t u r e , a n d v e r t i c a l s k e le t a l i n -c r e a s e s a r e p l a n n e d .

Up p er to o th to l ip re la t io n sh ip ( F i g . 8 ) . T h e d i s -t a n c e f r o m u p p e r l i p i n f e r i o r t o m a x i l l a r y i n c i s a l e d g ei s m e a s u r e d ( F i g . 8 ) . T h e n o r m a l r a n g e i s 1 t o 5 m m . tW o m e n s h o w m o r e w i t h i n t h is ra n g e . S u r g i c a l a n do r t h o d o n t i c v e r t i c a l c h a n g e s a r e b a s e d p r i m a r i l y o n t h i sm e a s u r e m e n t ( i .e . , p o s t s u r g i c a l i n c i so r e x p o s u r e r a n g eo f l t o 5 m m ) .

C o n d i t i o n s o f d i s h a r m o n y a r e p r o d u c e d b y f o u rv a r i a b l e s :

1 . I n c r e a s e d o r d e c r e a s e d a n a t o m i c u p p e r l ip le n g t h( i n f r e q u e n t l y ) .

2 . I n c r e a s e d o r d e c r e a s e d m a x i l l a r y sk e l e t a l l e n g t h( f r e q u e n t l y ) .


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r . }Interlabial Gap

LI.~

F i g . 9 . I n t e r l a b i a l g a p i s m e a s u r e d i n r e l a x e d l i p p o s i t i o n f r o mu p p e r l i p i n f e r i o r (ULI ) t o l o w e r l i p s u p e r i o r ( LLS) .

3. Thick upper l i ps expose l e ss i nc i sor t han th inupper l i ps , a l l o the r fac tors be ing equa l .

4 . T h e a n g l e o f v ie w c h a n g e s t h e a m o u n t o f i n c iso rv i s ib l e to the v i ewer . The th ree va r i ab le s tha tcont r ibu te to the angle of v i ew a re (1) t he pa -t i en t ' s he igh t , (2 ) t he obse rve r ' s he igh t , and (3)the d i s t ance f rom the fac i a l sur face of t he upperl ip to the inc i s ive edge ( inc reased l i p th i cknessrevea l s l e ss re l a t ive too th exposure ) .

O v e r i m p a c t i o n o f u p p e r i n c i so r t e e t h l e a d s t o t h ea p p e a r a n c e o f p r e m a t u r e a g i n g , e sp e c i a l l y in c o n j u n c -t ion wi th maxi l l a ry re t rac t ion . Thi s t ype of surg ica lm o v e m e n t i s r a r e l y i n d i c a t e d . P o s t e r i o r m o v e m e n t o fthe maxi l l a ry inc i sors i s i nd ica t ed on ly for t rue max-i l l a ry pro t rus ion . Or thodont i c ove r re t rac t ion , which i su se d t o o c c l u sa l l y c o r r e c t m a n d i b u l a r r e t r u s i o n , p r o -d u c e s p r e m a t u r e a g in g o f t h e f a c e .

l n t e r l a b i a l g a p ( F i g . 9) . Wi th the l i ps re la xed , asp a c e o f 1 to 5 m m ~ b e t w e e n u p p e r l ip i n f e r io r a n dlower l i p supe r ior i s p resen t (F ig . 9 ) . Females show al a rge r gap wi th in the normal range ." Thi s measurementi s a l so dependent on l i p l eng ths and ve r t i ca l den to-ske le t a l he igh t .

Inc reases in in t e r l ab ia l gap a re seen wi th ana tomicshor t upper l i p , ve r t i ca l maxi l l a ry excess , and mandib-u l a r p r o t r u s io n w i t h o p e n b i t e s e c o n d a r y t o c u sp i n te r -fe rences . Decreased in t e r l ab ia l gap i s found wi th ve r -t i ca l maxi l l a ry de f i c i ency , ana tomica l ly long upper l i p

(na tura l change wi th ag ing , e spec ia l ly in ma les) , andmandibula r re t rus ion wi th deep b i t e . Abnormal i t i e ssh o u l d b e c o n s i d e r e d w h e n p l a n n in g sk e l e t al c h a n g e s .A n a n a t o m i c a l l y sh o r t u p p e r l i p sh o u ld b e r e c o g n i z e das a sof t t i ssue prob lem and should no t be t rea t ed byexces s ive ly shor t en ing the maxi l l a . Thi s can l ead to ashor t , round fac i a l ou t l i ne .

C l o s e d l ip p o s i t i o n . E v e n t h o u g h a n u n d e r s t a n d in gof re l axed l i p pos i t i on i s e ssen t ia l , an unders t and ing o fc losed l i p pos i t i on adds suppor t t o d i agnos t i c pa t t e rns .T h e c l o se d l i p p o s i t io n a l so r e v e al s d i sh a r m o n y b e t w e e nske le t a l and sof t t i ssue l eng ths .

Inc rease d menta l i s con t rac t ion (men ta l i s s tra in) , l i ps t ra in , and a l a r base na r rowing a re obse rved in ve r t i ca lske le t a l excess , ana tom ic shor t upper l ip and som e caseso f m a n d i b u l a r p r o t r u s io n w i t h o p e n b i t e .

L ip redundancy i s seen wi th ve r t i ca l maxi l l a ry de -f i c i ency and m andibu la r re t rus ion wi th deep b i t e . W i thba lanced l i p and ske le t a l l eng ths , t he l ips should idea l lyc lose f rom a re l axed , sepa ra t ed pos i t i on wi thout l i p ,men ta l i s , o r a l a r base s t ra in . The m axi l l a should no t beimpac ted to idea l i ze the shor t upper l i p c losure un lessthe fac i a l ou t l i ne w i l l t o l e ra t e such a change .

S mi le p o s i t id n l ip leve l . W h e n e x a m i n i n g t h e sm i l epos ture , d i f fe ren t l i p e l eva t ions a re obse rved in normaland abnormal ske le t a l pa t t e rns . Idea l exposure w i thsm i l e i s t h re e - q u a r t er s o f t h e c r o w n h e i g h t t o 2 m m o fg ing iva , f ema les more than ma les .~ Var i ab i l i t y in g in-g iva l exposure i s r e l a t ed to ( I ) l i p l eng th , (2 ) ve r t i ca lmaxi l l a ry l eng th , (3 ) maxi l l a ry ana tomic c rown l ength ,and (4) magni tude of l i p e l eva t ion wi th smi l e .

E x c e s s g i n g i v a l e x p o su r e m a y b e c a u se d b y a sh o r tupper l i p , ve r t i ca l maxi l l a ry excess , shor t c l in i ca lc r o w n , a n d / o r l a r g e l ip e l e v at i o n w it h sm i li n g . B e c a u seof e t io log ic va r i ab i l it y , surg ica l shor t en ing o f t he max-i l l a i s i nd ica t ed on ly when excess g ing iva l exposure i sfound in combina t ion wi th inc reased in t e r l ab ia l gap ,inc reased too th exposure , i nc reased lower face he igh t ,a n d / o r m e n t a l i s s t r a i n .

Def i c i en t exposure e t io log ic fac tors i nc lude a longu p p e r l i p , v e r t i c a l m a x i l la r y d e f i c i e n c y , a n d / o r m i n i m a lsmi l e l i p e l eva t ion . Decreased inc i sor exposure i st r e a te d w i t h m a x i l la r y l e n g t h e n i n g w h e n f o u n d i n c o m -bina t ion wi th dec reased in t e r l ab ia l gap- l ip redundancy ,sh o r t l o w e r o n e - t h i r d f a c e h e i g h t, a n d n o r m a l u p p e r l i pl ength .

W h e n i m p a c t i n g o r l e n g t h e n in g t h e m a x i l l a o n t h eb a s i s o f r e p o se d i n c i so r e x p o su r e , g i n g i v a l sm i l e e x -p o su r e sh o u l d a l so b e c o n s i d e r e d . F o r e x a m p l e , i f t h epa t i en t has normal smi l e g ing iva l exposure (1 to 2 mm)and the inc i sors a re l eng thened to t r ea t dec reased re -l a x e d l i p i n c i so r e x p o su r e , e x c e s s i v e sm i l e g i n g i v al e x -posure w i l l r e su l t .

Pa r t i cu la r ca re should be t aken wi th shor t c l in i ca l


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G ,

Sn

Fig. 10. Prof i le angle is measured by connect ing points glabel la( G ' ) , subnasale ( S n ) , and sof t t issue pogonion ( P g ' ) . The angleis measured on the lef t hand side with the pat ient facing r ight.

Fig. 11. Nasolabial angle is developed by connect ing columellal ine ( infer ior nasal septum) ( C ) , subnasaTe S n ) , and upper l ipanter ior point ( U L A ) .

c r o w n s . A 3 t o 4 m m r e p o s e i n c is o r e x p o s u r e m a ye x p o s e u n a c c e p t a b l e a m o u n t s o f g i n g i v a w h e n s m i l in gbecause of shor t maxi l l a ry inc i sor c rowns . Thi s s i tua -t ion is p rope r ly t rea t ed by p lac ing no rmal l eng th c row ns(venee rs ) on the maxi l l a ry inc i sors and t rea tment p l an-n i n g f r o m t h e r e p o s e a n d s m i l e p e r sp e c t i v e . T h e " g i n -g iva l smi le" i s neve r t rea t ed to idea l a t t he expense ofunderexpos ing the inc i sors in the re l axed l ip pos i t ion .P R O F I L E V I E W

Natura l head pos ture , cen t r i c re l a t ion , and re l axedl ips a re used to accura te ly a s ses s p rof i l e . 'P r o f i l e a n g l e ( F i g . 10)

This angle i s fo rmed by connec t ing sof t t i s sue g la -be l l e , subnasa le , and sof t t i s sue pog onio n ' (F ig . 10). 7.8G e n e r a l h a r m o n y o f t h e f o r e h e a d , m i d f a c e , a n d l o w e rface i s appra i s ed wi th th i s angle . Maxi l l a ry and man-d ibu la r basa l bone an te ro pos te r io r d i s c repanc ies a reeas i ly v i sua l i zed . Clas s I occ lus ion presen t s a to t a l fa -c i a l ang le range of 165 ~ to 175~ ' C las s I I ang les a rel e s s than 165 ~ and Clas s I I I a re g rea te r than 175 ~Ske le t a l d i s c repanc ies p roduc ing Clas s I I angula t ion

inc lude maxi l l a ry pro t rus ion ( ra re ) , ve r t i ca l maxi l l a rye x c e s s ( c o m m o n ) , a n d m a n d i b u l a r r e tr u s io n ( c o m m o n ) .Clas s I I I ske le t a l pa t t e rns inc lude maxi l l a ry re t rus ion( c o m m o n ) , v e r t i c a l m a x i l l a r y d e f i c i e n c y ( r a r e ) , a n dm a n d i b u l a r p r o t r u s i o n ( c o m m o n ) .

Surg ica l p rocedures should gene ra l ly addres s thecosmet i c imba lance e s t ab l i shed wi th th i s angle . Theprof i l e angle i s t he mos t impor tan t key to the need fora n t e r o p o s t e r i o r s u r g i c a l c o r r e c t i o n . W h e n v a l u e s a r el e ss than 165 ~ or g rea te r than 175 ~ ske le t a l ma locc lu-s io n s n e e d i n g s u r g e r y a r e p r o b a b l y t h e c a u s e . A n g l e sa t t he ex t re me of no rmal (grea te r than 175 ~ or l e s s than165 ~ a re usua l ly caused by ske le t a l d i sha rmony. Sof tt i s sue th i cknes s d i f fe rences a re no t capable of caus ingt h e se e x t r e m e a n g l e c h a n g e s .N a s o l a b l a l a n g l e ( F i g . 1 1 )

T h i s a n g l e i s f o r m e d b y t h e i n t e rs e c t io n o f t h e u p p e rl ip an te r io r and co lumel l a a t subnasa le (F ig . 11) . Thi sa n g l e c a n c h a n g e n o t i c e a b l y w i t h o r t h o d o n t ic a n d s u r -g ica l p rocedures tha t a l t e r t he an te ropos te r io r pos i t ionor inc l ina t ion of the max i l l a ry an te r io r t ee th . 9 I ' A l lprocedures should p lace th i s angle in the cosmet i ca l ly


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402 A rn e t l al td H er gm a/ z American Journal of Orthodontics and Dentofac ial OrthopedicsMay 1993

MxSC

F i g . 1 2 . M a x i l l a r y s u l c u s c o n t o u r (MxSC) s s u b j e c t i v e l y a s -s e s s e d . T h e c o n t o u r i s d e s c r i b e d a s e i t h e r a c c e n t u a t e d , g e n t l ec u r v e ( n o r m a l ) o r f l a t . M e a s u r e m e n t o f t h i s c o n t o u r i s i m p r a c -t i ca l .

des i rab le range of 85 ~ to 105~ I Female pa t i en t s w i l lusua l ly be more ob tuse w i th in th i s range . Fac tors t o becons ide red in t r ea tmen t p l anning to cor rec t ly ach ieveth i s ang le a re a s fo l lows:

I . Exi s t ing angle .2 . T i l t i n g v e r su s b o d i l y m o v e m e n t o f m a x i l l a r y

t ee th (or thodont i c and surg ica l ) and pred ic t ede f fec t on the ex i s t ing l i p pos i t i on .

3 . Es t ima t ion of li p t ens ion presen t . Tense l ips maym o v e m o r e p o s t e r i o r l y w it h t o o t h a n d b a sa l b o n emovement and l e ss an te r io r ly . F l acc id l i ps maymove l e ss w i th pos t e r io r t oo th and basa l bonem o v e m e n t a n d l e s s w i th a n t e r i o r . ' - " "

4 . Ante ro pos te r io r li p th i ckness . Th in l i ps (6 to 10ram) 9"12"~3 m ay m ov e mo re wi th tooth re t ract ionm ov em en t than thick l ips (12 to 20 m m ). I-''~4

5 . T h e m a g n i t u d e o f t h e m a n d i b u l a r r e t ru s i o n(over j e t ) . The l a rge r t he ove r j e t d i s t ance , t hemore re t rac t ion of t he m axi l l a ry inc i sors w i l l benecessary, thus opening the nasolabial angle . .gLz

6 . T h e f o l l o w i n g f a c to r s a f f e c t t h e a n t e r o p o s t e r io rm o v e m e n t o f i n c i so r t e e t h a f t e r e x t r a c t i o n s :A m o u n t o f a n te r i o r c r o w d i n g , sp a c e s , t o o t h

m a ss p r o p o r t i o n ( u p p e r v e r su s l o w e r ) , p o s -t e r i o r r o t a t i o n s , c u r v e o f S p e e ( u p p e r v e r su slower ) , and anchorage (headgea r , Class I Ie last ics) .7 . Ext rac t ion ve rsus nonex t rac t ion .

8 . Ext rac t ion pa t t e rn ( f i rs t ve rsus secon d pre -mola rs ) .

I f t he naso lab ia l ang le i s open (approxima te ly ,105 ~re t rac t ion o f an te r io r t ee th or thodon t i ca l ly and surg i -ca l ly should be avoided in t r ea tment p l anning . L ike -w i se , a l o n g n o se w i l l b e c o m e a d v e r se l y p ro m i n e n t w i t hl ip re t rac t ion . P resen t l imi t ed kno wledg e of how l ipsr e sp o n d t o a n t e r o p o s t e r i o r m o v e m e n t o f t h e t e e t h d ic -t a t e s a c o n se r v a t i v e a p p r o a c h w h e n l a r g e m o v e m e n t sa r e c o n t e m p l a t e d . Crowding dictates t h e n e e d f o r e x -t rac t ion , f ac i a l ba l ance in f luences which t ee th a re ex-t rac t ed and how spaces a re c losed .

S u r g i ca l m o v e m e n t o f t h e m a x i l l a a lso a f f e c t s t h enaso lab ia l ang le . The same fac tors t ha t a f fec t o r tho-d o n t i c c h a n g e sh o u l d b e a n a l y z e d w h e n c o n s i d e r i n gm a x i l l a r y m o v e m e n t . A s a g e n e r a l r u l e , t h e m a x i l l ash o u l d n o t b e m o v e d p o s t e r i o r ly i n t re a t in g d e n t o f a c i a ld e f o r m i t i e s , e sp e c i a l l y i n c o m b i n a t i o n w i t h su p e r i o rrepos i t i on ing . Thi s c rea t e s nasa l e longa t ion , a l a r basedepress ion , and opening of t he naso lab ia l ang le , a l l o fwhich c rea t e fac i a l p remature ag ing . Inadver t en t max-i l l a ry re t rac t ion occurs w i th i so l a t ed LeFor t surge ryw h e n t h e V T O x - r a y f i l m i s t a k e n w i t h t h e c o n d y l e son the eminence ra the r t han sea t ed in the fossa .M a x i l l a r y s u l c u s c o n t o u r ( F i g . 1 2 )

No rm al ly th i s su l cus i s gen t ly cu rved 15 and g ivesinforma t ion rega rd ing up per l ip tens ion (F ig . 12). W i thl ip t ens ion , t he su l cus co ntou r f la t tens . F l acc id l i ps fo rman accentua ted curve wi th the ve rmi l ion l i p a rea show-ing an accen tua t ion of cu rve . ,2 The f l acc id l i p gene ra l lyi s t h i ck (12 to 20 mm f rom an te r io r ve rmi l ion to l ab ia linc i sor ) g iv ing the l i p ( i . e . , he adgea r w i th Class I I e la s-t i c s o r func t iona l app l i ance t rea tment ) t he appea ranceo f b e i n g t o o f a r f o r w a r d r e l a t i v e to t h e t e e t h . '2 T h emaxi l l a should no t be re t rac t ed s ign i f i can t ly when adeeply curved , t h i ck l i p i s p resen t s ince th i s p roducespoo r l i p suppor t and cosm et i c s . I f poss ib l e , t he ma xi l l ash o u l d b e m o v e d f o r w a r d i n t o a t h i c k , c u r v e d l i p t oimprove l i p suppor t .M a n d i b u l a r s u l c u s c o n t o u r ( F i g . 1 3 )

This con tour i s a gen t l e curve ~ (F ig . 13) and canind ica t e l i p t ens ion . When deeply curved , t he lower l i pi s f l acc id in cha rac t e r (Class I1 , ve r t i ca l maxi l l a r3 /de -f i c ie n c y ) . T h e d e e p c u r v e i s u su a ll y s e c o n d a r y t o m a x -i l la ry inc i sor impinge men t in the case of deep b i t e ClassI I and ve r t i ca l maxi l l a ry de f i c i ency . When f l a t t ened ,the low er l i p demon st ra t e s t ens ion o f t issues (Class I11).


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American Journal of Orthodontics and Dentofacial Orthopedics Arnett and Bergman 403Volume 103, No. 5

( .O~

M~ SC

F i g . 1 3 . M a n d i b u l a r s u lc u s c o n t o u r (MdSC) s s u b j e c t i v e l y a s -s e s s e d . T h e c o n t o u r i s e i t h e r a c c e n t u a t e d , g e n t l e c u r v e ( n o r -m a l ) o r f l a t . M e a s u r e m e n t o f t h i s c o n t o u r i s i m p r a c t i c a l .

F i g . 1 4 . O r b i t a l r i m p r o j e c t i o n i s m e a s u r e d f r o m t h e a n t e r i o rm o s t g l o b e (Gb) o t h e o r b i t a l r im p o i n t (OR).A s u b j e c t i v e o r b i ta lr i m d e s c r i p t i o n i s a l s o g i v e n : N o r m a l , f l a t, o r p r o t r u d e d .

Surg ica l p rocedures tha t cor rec t t he basa l bone gene r -a l ly w i l l improve the mandibula r su lcus angle ( i . e . ,d e e p c o n t o u r a s so c i a te d w i th d e e p b i t e C l a s s I I m a l -occ lus ion or f l a tnes s a s soc ia t ed wi th mandibula r p ro-t rus ion).Orbi ta l r im(F ig . 14)

T h e o r b i ta l r i m i s a n a n t e r o p o s t e r i o r in d i c a t o r o fmax i l l a ry pos i t ion . D ef i c i en t o rb i t a l r ims m ay cor re l a t epos i t iona l ly wi th a re t ruded maxi l l a ry pos i t ion becausethe os seous s t ruc tures a re o f t en de f i c i en t a s g roups ,ra the r than in i so la t ion . The g lobe normal ly i s pos i -t ioned 2 to 4 m m ante r io r to the orb i t a l r im (F ig . 14) . tThe surg ica l maxi l l a ry ve rsus mandibula r dec i s ion i sin f luenced by the orb i t a l r im pos i t ion . Def i c i en t o rb i t a lr i m s d i c t a t e m a x i l l a r y a d v a n c e m e n t , a l l o t h e r f a c t o r sb e i n g e q u a l .C h e e k b o n e c o n t o u r ( F ig s . 1 5 a n d 1 6 )

C h e e k b o n e a s s e s s m e n t r e q u i r e s f r o n t a l a n d p r o f i l eexam ina t ion s imul t ane ous ly (F igs . 15 and 16) . Ch eek-b o n e c o n t o u r ( C C ) c o r r e l a t e s w i t h m a x i l l a r y a n t e r o -p o s t e r i o r p o s i t i o n , f r e q u e n t l y th e c h e e k b o n e c o n t o u r i s

de f i c i en t i n combina t ion wi th maxi l l a ry re t rus ion . De-f i c i e n t c h e e k b o n e s m a y c o r r e l a t e p o s i t i o n a l l y w i t h are t ruded maxi l l a ry pos i t ion because the os seous s t ruc -tures a re o f t en de f i c i en t a s g roups , ra the r than in i so-l a t i o n . C h e e k b o n e c o n t o u r i s u s e d a s o n e o f t h e m a i nind ica tors o f ma xi l l a ry re trus ion . Th i s a rea should hav ea n a p e x a t t h e c h e e k b o n e p o i n t ( C P ) a n d n o t a p p e a rf ia t. T he C P i s l oca ted 20 to 25 m m infe r io r and 5 to1 0 m m a n t e r i o r t o t h e o u t e r c a n t h u s ( O C ) o f t h e e y ew h e n v i e w e d i n p r o f i le (F i g . 1 5) . W h e n v i e w e d f r o n -t a l ly the CP i s 20 to 25 m m infe r io r and 5 to 10 mmla te ra l t o the OC (F ig . 16). I t should be no ted tha t t ruem a n d i b u l a r p r o g n a t h i s m c a n s h o w m i l d m a l a r f l a tn e s sa s a r e l a t i v e o b s e r v a t i o n t o t h e e x t r e m e c h i n p r o t r u s i o n .True maxi l l a ry hypoplas i a o f t en i s a s soc ia t ed wi th t ruem a l a r d e f i c ie n c y .N a s a l b a s e - l i p c o n t o u r ( F ig s . 1 5 a n d 1 6 )

T h e n a s a l b a s e - l i p c o n t o u r ( N b - L C ) l i n e r e q u i r e s- ' - f ron ta l and prof i l e examina t ion s imul t aneous ly (F igs .

15 and 16). Th e l ine i s t he cont inua t ion o f the cheek -b o n e c o n t o u r l i n e . T h i s a r e a i s a n i n d i c a to r o f m a x i l l a r yand ma ndibula r ske le t a l an te ro pos te r io r pos i t ion . Nor -


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40 4 Arlzell atzd Bergman American Jot*rnal of Orthodontics and Dentofacial OrthopedicsMay 1993

ZYGOI~t.' I[IC AIt'CH,MtEA 0IR~OU~COI, I'OUItA~F-& 0ttt,'l~lROL AleF, 0NA.,,~,AI. M.,~E It.'IP R~L I~ (~

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Figs . 15 a nd 16. Chee kbo ne conto ur is anteriorly facing, curved l ine that starts just anterior to ear,ex tend ing forward th rough chee kbone po in t (CP) , then ex tending anteridr- inferior ly ending at m axi l lapo in t (MxP) adjace nt to alar base of nose. F.or descript ive purposes the c hee kbon e contour is div idedinto three areas: (1) zygomatic arch, (2) middle contour area, and (3) subpupi l areas. These threeareas, when tak en together, consti tute the cheek bone contour. Reconstruction of chee kbon e contour,whe n defic ient, should a nalyz e al l three parts sepa rately in terms of correction. CP and MxP indicatesosseous chee kbon e and ma xi l lary bas e posi tions, respectively. The nasal base -l ip contour (Nb-LC)exten ds inferiorly from the ma xi l la point (MxP ) as a gentle, ante riorly facing curve, end ing just be lowand latera l to the mo uth commissure. In normoskeletal patients the chee kbon e-na sal base-l ip contourcom plex is a smooth continuation, a nteriorly facing, curved l ine. This l ine, when v iewe d frontal ly orfrom the side, is a defin i te f lowing curve w i th no interruptions which are ap pare nt wi th skeletal defor-mities.

M axillary Retrusion mal pos i t i on i s i nd ica t ed by the maxi l l a po in t (MxP)d i r e c t ly b e h i n d t h e a l a r b a se . T h e M x P i s t h e m o s ta n t e r i o r p o i n t o n t h e c o n t i n u u m o f t h e c h e e k b o n e - n a sa l -l i p contour and i s an ind ica t ion of maxi l l a ry an te ro-pos t e r io r pos i t i on .Ma xi l l a ry re t rus ion i s i nd ica t ed by a s t ra igh t o r con-c a v e c o n t o u r a t M x P ( F i g . 1 7 ). W h e n t h i s a n a t o m i ca r e a i s c o n c a v e o r f i a t, m a x i l la r y a d v a n c e m e n t i s n e c -essa ry .Mandibula r p ro t rus ion in t e r rup t s t he nasa l base - l ipl ine in the l eng th of the upp er l ip (F ig . 18). W hen thel ine i s i n t e r rup ted wi th in the he igh t o f t he upper l i p am a n d i b u l a r s e t b a c k m a y b e i n d i ca t e d .N a s a l p r o j e c t io n ( F ig . 1 9 )

T h e n a sa l p r o j e c t i o n ( N P ) m e a su r e d h o r i z o n t a l l yf rom subnasa le to nasa l t i p i s normal ly 16 to 20 mmFig. 17. Ma xi l lary retrusion: C heek bone -nasa l base-l ip cu rve isinterrupted at MxP .


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American Journal of Orthodontics and Dentofacial Orthopedics Ar ne lt an d Berg nlan 4 0 5Volume 1 0 3 , N o . 5

Mandibular Protrusion

Fig . 18. Mand ibu lar pro trus ion: C heek bone -nasa l base- l ip curveis in ter rupted in upper l i p area .(F ig . 19) . ' Nasa l p ro j ec t ion i s an ind ica tor o f maxi l l a rya n t e r o p o s t e r i o r p o s i t io n . T h i s l e n g th b e c o m e s p a r t i c u -l a rl y i m p o r t a n t w h e n c o n t e m p l a t i n g a n t e r io r m o v e m e n tof the max i l l a . Dec reased n asa l p ro j ec t ion cont ra ind i -ca t e s maxi l l a ry advancement . Wi th a Class I I I ma loc -c lus ion , shor t no se , and a l l o the r fac tors equa l , 9 man-d ibu la r se tback i s i nd ica t ed .T h r o a t l e n g t h a n d c o n t o u r ( F i g . 2 0 )

T h e d i s t a n c e f r o m t h e n e c k - t h r o a t j u n c t i o n t o t h eso f t t is su e m e n t o n sh o u l d b e n o t e d ( F i g . 2 0 ) . N o m i l-l i m e t e r m e a su r e m e n t i s n e c e s sa r y , b u t a p l a n n e d m a n -d ibu la r se tback wi l l change th i s l eng th . The pred ic t edes the t i c re su l t should produc e a normal appea r ing l engthwi thout sagging . A pa t i en t w i th a shor t , sagging th roa tl ength i s no t a good candida te for mandibula r se tback .A long , s t ra igh t t h roa t leng th i s amenab le to mandibula rse tback . Of t en a mandibula r se tback i s necessa ry w i thch in augmenta t ion to ba l ance l i ps w i th ch in and ma in-t a in th roa t l eng th . Su c t ion l i pec tom y is a use fu l ad junc tfor cont ro l l i ng subm enta l sag wi th se tbacks or wheni so la t ed fa t accumula t ion i s p resen t .S u b n a s a l e - p o g o n i o n l in e ( S n - P g ' ) ( F i g . 2 1 )

Burs tone repor t ed tha t t he upper l i p i s i n f ron t o ft h e S n - P g ' l i n e b y 3 .5 m m 1 . 4 m m , a n d t h e l o w e rl ip is in front of the l ine by 2 .2 m m --- 1.6 mm . 16

The re l a t ionsh ip of t he l i ps t o the Sn-Pg ' l i ne i s animpor t an t a id in o r thodont i c sof t t i ssue ana lys i s andt r e a tm e n t . T o o t h m o v e m e n t c h a n g e s t h e r e la t io n sh i p o fthe l i ps t o the Sn-Pg ' l i ne and the re fore the e s the t i c

NPNT

Fig . 19. Nasal project ion ( N P ) i s measured f rom sub nasa le (S n )t o nasa l t ip (NT ) . T he l ines t h rough S n a n d N T are perpendicu larto the f loor when the head i s in a na tura l pos tura l pos i ti on .

F i g . 20 . T h roa t l eng t h ( T L ) is assessed f rom neck-throat point( N TP ) t o sof t ti ssue me nton " (Me ' ) . This d is tance i s sub jec t i ve lydesc r ibed as e i ther normal , l ong or shor t l ength , and w i th orw i thout sag.


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406 Arnett and Bergman American Journal of Orthodontics and Demofacial OrthopedicsMay 1993

S n

Fig . 21. Subnasa le-pogonion re ference l i ne i s generatedt h rough po i n t s s ubnas a l e ( S n ) and s o ft t i s s ue pogon i on ( P g ' ) .Lip pro jec t ions are eva luated re la t i ve to th is l ine .

re su l t . A l l t oo th movement s should be a ssessed in re -ga rd to the an t i c ipa t ed l i p change to the Sn-Pg ' l i ne .E x t r a c ti o n s sh o u l d b e a v o i d e d w h e n t h e y m o v e t h e t e e thand c rea t e re t rac t ion of t he l i ps (d i shed- in) beh ind th i sl i ne (F ig . 22) . O n the o the r hand , i f unrave l l ing thec rowding wi th ex t rac t ions a l lows for l i p ba l ance to theSn-P g ' l i ne , t he ex t rac t ions a re e s the t i ca l ly accep tab le .

The re l a t ionsh ip of t he l i ps t o th i s l i ne i s a f fec t edby the fo l lowing fac tors :

1 . Ske le t a l r e l a t ionsh ip : W hen an te r io r o r pos t e r io rsk e l e t a l d i sh a r m o n y e x i s t s , p r o d u c i n g o v e r j e tabnormal i t i e s (pos i t i ve or nega t ive ) , t he Sn-Pg 'has no va l id i ty .

2 . Inc i sor i nc l ina t ions : Wi th a Class I ske l e t a l pa t-t e rn , t he upper and lower inc i sors must be a tprope r ove r j e t and ax ia l i nc l ina t ion to p roduceproper p ro t rus ion of t he l i ps re l a t ive to the Sn-Pg ' l i ne .

3 . L ip th i ckness : Th e l ip re la t ionsh ip to the Sn-Pg 'l i ne i s dependent on l i p th i ckness . The Burs tonere l a t ionsh ip t6 i s t rue o n ly i f t he l i ps a re the sam eth ickness , a l l o the r fac tors be ing idea l . Class Iinc i sors (upper inc i sor i n f ron t o f l ower inc i sor )produce Class I l i ps (upper l i p in f ron t o f l owerl ip ) on ly i f t he l i ps a re o f equa l t h i ckness .

Thi s l i ne i s a l so used when p lanning surge ry on theV T O ( F i g . 2 3 ) . T h e S n - P g ' l i n e i s id e a l ly d r aw n t o t h e

l ips th rough subnasa le . I f Pg ' i s s ign i f i can t ly pos t e r io rto the l i ne , a ch in augmenta t ion i s i nd ica t ed . Femalech ins a re sof t e r r e l a t ive to th i s l i ne .S O F T T IS S U E C H A R A C T E R I S T I C S O F C O M M O NS K E L E T A L D E F O R M I T IE S

With the 19 fac i a l keys , 8 pure ske le ta l de formi t i e swi th pred ic t ab le sof t t issue appea rances can be d e f ined .T h e g r e a t e r m a g n i t u d e o f t h e sk e l e t a l d e f o r m i t y t h emo re d i s t inc t the sof t t i ssue pa t t e rn . Ske le t a l de formi t i e sm a y occur hz combination ( i . e . , ve r t i ca l maxi l l a ry ex-cess w i th mandibula r p rogna th i sm) and fac i a l t r a i t s a rethe re fore b l ended . In a l l ca ses , f ac i a l t r a i t s a re he lpfu li n d i ag n o s i n g sk e l e t al p r o b l e m s . T h e e i g h t u n c o m b i n e do r p u r e o r u n m i x e d a n t e r o p o s t e r i o r f a c ia l - sk e l e ta l t y p e sa re a s fo l lows:

A . Class I f ac i a l and den ta l ( fac i a l ang le Class l )( F i g . 2 4 )1 . Ver t ica l maxi l l a ry excess (Table lI )2 . Ver t ica l maxi l l a ry de f i c i ency (Table I I I )

B. Class I I f ac i a l and den ta l ( fac i a l ang le Class I I )( F i g . 2 5 )3 . Ma xi l l a ry pro t rus ion (Table IV)4 . Ver t ica l max i l l a ry excess (Table I I )5 . Ma ndibu la r re t rus ion (Table V)

C. Class I I I fac i a l and den ta l ( fac i a l ang le Class I I I )( F i g . 2 6 )6 . M axi l l a ry re t rus ion (Table VI )7 . Ver t i cal maxi l l a ry de f i c i ency (Table I l l)8 . M andibu la r p ro t rus ion (Table VI I )

Kn owin g the e igh t unm ixed ske le t a l pa t t e rns i s he lp-fu l i n o rganiz ing fac i a l ana lys i s i n form a t ion in to a co-hes ive , meaningfu l whole . Wi thout fac i a l ana lys i s , d i s -t i ngui sh ing the ske le t a l source of t he ma locc lus ion canbe d i f f i cu l t . Fac ia l t r a i t i den t i f ica t ion and ca t egor i za t ionleads to a d i f fe ren t i a l d i agnos i s o f ske l e t a l pa t t e rns(Table VI I I Class I I , Table IX Class I l l ) . Ce pha lom et r i cana lys i s has been s how n to be ine f fec t ive in th i s rega rd .The advantage of a d i agnos i s based on fac i a l t r a i t s i si m p o r t a n t . S k e l e t a l m a l o c c l u s i o n s h a v e p r o f o u n d so f tt i ssue imba lance tha t pa t i en t s expec t t o be cor rec t ed .Fac ia l based t rea tment p l anning ensures tha t f ac i a lc h a n g e w i l l b e c o r r e c t , w h e r e a s c e p h a l o m e t r i c s h a v eb e e n sh o w n t o h e u n r e l i a b l e .O R T H O D O N T I C P R E P A R A T I O N F O R S U R G E R Y

Fac ia l and den ta l d i sc repanc ies may no t be propor -t i o n a te b e c a u se o f d e n t a l c o m p e n sa t i o n s t o t h e a n t e r o -pos t e r io r ske l e t a l ma la l ignm ent . ~7 Denta l com pens a -t ions a re inc i sor ax ia l i nc l ina t ion changes in re sponset o i n c r e a se d o r d e c r e a se d o v e r j e t . M a n d i b u l a r r e t r u s i o nand , occas iona l ly , ve r t i ca l maxi l l a ry excess a re a sso-c i a t ed wi th lower inc i sor f l a r ing and upper inc i sor up-


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A m e ri can J ourna l o f O r th t M ont ic s and D e n te ~aci a l O r thoped i cs A r ne t t an d B e rg m an 4 0 7Volume 103, No. 5

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F i g . 2 2 . A , N o r m a l l ip r e l a t io n s h i p to S n - P g ' l in e . B , P r e m a t u r e a g i n g a s s o c i a t e d w i th p r e m o l a r e x -t r a c t io n s a n d i n c i s o r r e t r a c ti o n . T h e l i p s fa l l o n o r b e h i n d t h e S n . ~ P g' i n e g i v i n g t h e " d i s h e d - i n " o r t h o d o n t i ca p p e a r a n c e . T h e n a s o l a b i a l a n g l e m a y a l s o o p e n t o u n a c c e p t a b l e ra n g e s .

r igh t ing . Mandibula r p ro t rus ion , maxi l l a ry re t rus ionand ve r t i ca l maxi l l a ry de f i c i ency a re a ssoc ia t ed ~vi thu p p e r i n c i so r f la r in g a n d l o w e r i n c i so r u p r i g h t i n g .

Ext rac t ion pa t t e rns and mechanics a re a imed a t r e -m o v i n g d e n t a l c o m p e n sa t i o n s . b e f o r e su r g e r y . C o m p e n -sa t ion rem ova l l eads to be t t e r fac i a l r e su l t s . An ex am pleof th is i s a 10 mm ske le t a l man dibula r re t rus ion . Inc i sord e n t a l c o m p e n sa t i o n s t o t h e o v e r j e t m a y d e c r e a se t h e10 mm over j e t t o 5 ram. I f t he mandib le i s advancedwi th the compensa t ions presen t , t he ch in de f i c i ency i ss t i l l 5 mm. In cont ra s t , when den ta l compensa t ions a rer e m o v e d , t h e 1 0 m m o v e r j e t a n d 1 0 m m c h i n re t r u s io na re s imul t aneous ly and to t a l ly cor rec t ed wi th surg ica la d v a n c e m e n t .

I n a p p r o p r ia t e o r t h o d o n t i c p r e p a ra t i o n ( e . g . , u p p e rf ir st p rem ola r ex t rac t ions , he adge a r and Class I I e l a s t i c sto t r ea t a ske l e t a l mandibula r re t rus ion) d i s to r t s t heequa l i ty o f t he den ta l and fac i a l p rob lems fa r more thandenta l compensa t ions . In an a t t empt to cor rec t t he b i t ew i t h o u t su r g e r y , th e d e n t al d i s c r e p a n c y b e c o m e s m u c hless than the fac i a l d i sc repancy magni tude . Subse -quent ly , i f surge ry i s used for den ta l cor rec t ion , the sof tt i ssu e p r o b l e m i s o n l y m i n i m a l l y c o r r e c t e d . T h i s p r o b -l em l eads to the conc lus ion tha t surge ry should bep lanned f rom the beg inn ing to ob ta in op t ima l fac i a lchanges w i th b i t e cor rec t ion . ' 7"~ Ext rac t ions should bep lanned a round fac tors i nc lud ing , most impor t an t ly ,c rowding , pe r iodonta l needs , and fac i a l impl i ca t ions .G e n e r a l l y , e x t r a c t io n p a t t er n s d e c r e a se d e n t a l c o m p e n -sa t ion to the inc i sor ove r j e t p rob lem.

T h e m o s t c o m m o n a p p r o p r i a t e e x t r a c t i o n s f o r r o u -t ine fac i a l - ske le t a l de formi t i e s a re a s fo l lows:

rSn

Ideal

t p g 'lkNeeded Chl.eAugmmtatloe

F i g . 2 3 . S n - P g ' l i n e i s f r e q u e n t l y u s e d t o s u r g i c a l l y a s s e s s c h i n -l i p - n a s a l b a s e b a l a n c e . W i t h t h e v - r o o c c l u s i o n i n C l a s s I , t h el i n e is o r i e n t e d f r o m S n t h r o u g h i d e a l l i p p o s i t io n . I f P g ' f a l l s o nt h e c h i n , b a l a n c e o f c h i n - l i p - n a s a l b a s e i s i d e a l . I f P g ' f a l l sb e h i n d t h e l i n e , a c h i n a d v a n c e m e n t i s n e c e s s a r y t o o b t a i nb a l a n c e .

A. Class 1 fac i a l and den ta l ( ch in in ba l ance wi ththe face )1 . V e rt ic al m a x i ll a ry e x c e s s I v a r i a b l e2 . V e rt ic al m a x i l l a r y d e f i c i e n c y I v a r i a b l e


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American Journal o f Orthodontics and Dentofaeial Orthopedics4 0 8 A r n e t t a n d B e r g m a n M a y 1993

C L A S S I 's

O e i e n

Fig , 24 . Clas s I occ lusion and ch in p ro jec t ion can occur in combina t ion with ve r t ica l maxil la ry exces sor ver t i ca l ma x i l l a ry def i c iency . The anteropOs ter ior p ro f i le i s normal , but the v er t i ca l he ight o f t he faceis long or shor t.

T a b l e I I . V e r t i c a l m a x i l l a r y e x c e s s : c o m m o nf a c i a l c h a r a c t e r i s ti c s o f v e r t i c a l m a x i l l a r ye x c e s s a r e l i s t e d

Vertical maxil la ry excessIncreased lower one-thirdIncreased interlabial gapIncreased incisor exposureIncreased gingival smileMentalis strainDecreased total profile angle*Accentuated mandibular sulcus contourDecreased throat lengthNorm al nasal projectionNorm al nasotabial angle

*Class I VME can have a norm al total facial angle.

B . C l a s s I I f a c i a l a n d d e n t a l ( c h i n r e t r u d e d )1. M a x i l l a r y p r o t r u s i o n - - l o w e r s e c o n d a n d / o r

u p p e r f i r s t p r e m o l a r s , o r t h o d o n t i c c o r r e c t i o n .N o s u r g e r y r e q u i r e d .

2 . V e r ti c al m a x i l l a r y e x c e s s - - u p p e r e x t r a c ti o nb a s e d o n e x t e n t a n d l o c a t i o n o f c r o w d i n g ,l o w e r e x t r a c t i o n b a s e d o n e f f e c t s o n u p p e r l i ps u p p o r t w h e n L e F o r t I i s d o n e t o c o r r e c t v e r -t i c a l m a x i l l a r y e x c e s s .

3 . M a n d i b u l a r r e t r u s i o n - - u p p e r s e c on d p r e -m o l a r a n d / o r l o w e r f i rs t p r e m o l a r s . . . . .

C . C l a s s I I I f a c i a l a n d d e n t a l ( c h i n p r o t r u d e d )

4'

T a b l e I l l. V e r t i c al m a x i l l a r y d e f i c i e n c y : c o m m o nf a c i a l c h a r a c t e r i s t i c s o f v e r t i c a l m a x i l l a r yd e f i c i e n c y a r e l i s t e d

Vertical maxil lary def ic iencyDecreased lower one-thirdDecreased interlabial gapDecreased incisor exposureDecreased incisor exposure with smileLip redundancyStraight to Class I ll p rofile angle*Accentuated mandibular sulcus contourNorm al nasal projectionNorm al to decreased nasolabial angleIncreased throat lengthNorm al cheekbones, alar base

*Class I VMD can have a normal total facial angle.

1, M a x i l l a r y r e t r u s i o n - - u p p e r f ir st a n d l o w e rs e c o n d p r e m o l a r s

2 . V e r ti c al m a x i l l a r y d e f i c i e n c y - - u p p e r fi rs t a n dl o w e r s e c o n d p r e m o l a r s

3 . M a n d i b u l a r p r o t r u s i o n - - u p p e r fi rs t a n d l o w e rs e c o n d p r e m o l a r s

A n a d d i t i o n a l b e n e f i t o f t h e s u r g ic a l e x t r a c t i o n p a t -t e r n i s t h at t h e a n t i c i p a t e d s u r g i c a l r e l a p s e b e c o m e s t h eo p p o s i t e o f t h e o r t h o d o n t ic r e l a p s e p a tt e r n. A n e x a m p l eo f t h i s i s m a n d i b u l a r a d v a n c e m e n t w i t h l o w e r f i r st p r e -


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American Journal o f Orthtxlontics and Dentofacia/ Orthopedics Arnell and Bergman 409Volume 103, No. 5

C l a s s I I ' s

-< ~

/

E x c e ~Fig. 25. C lass II b i te and chin projection can be produced b y enti rely di f ferent skeletal patterns. M axi l laryprotrusion, m andibu lar retrusion and ve rt ical maxi l lary excess al l can produ ce identical bi tes w i th simi larchin profi les. The ar rows indicate the skeletal abno rma l i ty responsible for th e bi te an d profi le dis-harmony.

C l a s s I I I ' s

( .

V ~ l l a r yD e f i c i e n c ' ~

Fig. 26. C lass II I b i te and chin projection ca n be produced by e nti rely di f ferent skeletal patterns.Ma xi l lary etrusion, m andib ular protrusion, and vert ical m axi l larydefic iency al l can dem onstra te denticalClass II I b ite and simi lar profi le characterist ics. The ar rows indicate he skeletal abn orm al i ty esponsiblefor bi te an d facial p rofi le disharmony.

mo la r ex t rac t ions tha t have upr igh ted the low er inc i sors .Surg ica l r e l apse i s pos t e r io r , and or thodo nt i c re l apse a tthe lowe r inc i sors is an te r io r , i n t he oppos i t e d i rec t ion .T h e o r t h o d o n t i c r e l ap se i s a m e c h a n i sm t o c o m p e n sa t efor surg ica l r e l apse .

CONC LU S I O NOrthodo nt i s t s use den ta l and fac i a l keys to d i agnos e

and to t r ea t ma loc c lus ions . Denta l keys inc lude ove r j e t ,c~ fi ine occ lus ion , and mo la r occ lus ion . Th e den ta l keysa re g iven much we ight i n the de t e rmina t ion of t r ea t -


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4 1 0 A r n e t t a n d B e r g m a n

Tab l e IV . M a x i l l a r y p r o t r u s i o n : c o m m o n f a c i alc h a r a c t e r is t i c s o f m a x i l l a r y p r o t r u s i o n a r e l i s te d

Mar i l lary prot rus ion*Normal lower one-thirdNormal interlabial gapNormal incisor exposureNormal smileDecreased profile angleNormal mandibular sulcus contourNormal throat lengthNormal to short nasal projectionDecreased nasolabial angle

*Skeletal maxillary protrusion is rare.

Tab l e V . M a n d i b u l a r r e tr u s io n : c o m m o n f a ci a lc h a r a c t e r i s ti c s o f m a n d i b u l a r r e t r u s i o na r e l i s t e d

Man dibular r e t rus ionDecreased or normal lowe r one-thirdDecreased or normal interlabial gapNormal incisor exposureNormal smileNormal-to-lip redundancyDecreased profile angleAccentuated mandibular sulcus contourDecreased throat lengthNormal nasolabial angleNormal nasal projection

m e r it . F a c i a l k e y s a r e n o t u s e d b y s o m e o r t h o d o n t i s t sa n d s p a r i n g l y b y o t h e r s . T y p i c a l l y , f a c i a l k e y s u s e d b yo r t h o d o n t i s t s i n c l u d e t h e r e l a t i v e p o s i t i o n s o f t h e u p p e rl i p , l o w e r l ip , a n d c h i n . T h e s e g i v e i n f o r m a t i o n , b u to n l y l i m i t e d i n s i g h t i n t o t h e c o m p r e h e n s i v e d i a g n o s i s .

I n c o n t r a s t , w e h a v e p r e s e n t e d a n o r g a n i z e d , c o m -p r e h e n s i v e a p p r o a c h t o f a ci a l a n a ly s i s . W i t h t h i s a n a l -y s i s n o r m a l f a c i a l t r ai t s a r e m a i n t a i n e d a n d a b n o r m a lc h a r a c t e r i st i c s a r e c o r r e c t e d w i t h o r t h o d o n t i c s a n d s u r -g e r y . I n f o r m a t i o n f r o m f a c i a l e x a m i n a t i o n o f th e p a ti e n td i c t a t e s w h i c h p r o c e d u r e s r e s u lt i n o p t i m a l c o s m e t i c sw i t h C l a s s I f u n c t i o n . M e r e c o r r e c t i o n t o C l a s s 1 o c -c l u s i o n c a n g i v e r a n d o m , a n d o f t e n p o o r , c o s m e t i c r e -s u i t s . F u r t h e r , a r b i t r a r y c o r r e c t i o n t o C l a s s I o c c l u s i o nd o e s n o t e n s u r e e v e n p r e s u r g i c a l c o s m e t i c l e v e l s , t h e re -f o r e e s t h e t i c g u i d e l i n e s m u s t b e f o l l o w e d w h e n d e t e r -m i n i n g s u r g i c a l o r th o d o n t i c p l a n s : F o r t h is p u r p o s e 1 9k e y t r a i t s h a v e b e e n d e s c r i b e d .

REFERENCESI . Am ett GW, Bergman RT. Facial Keys to Orthodontic Diagnosisand Treatment Planning - Part I. AM J ORrHODDEN'I-OFACORTIIOP1993;103:299-312.

American Journal of Orthodontics and Dentofacial OrthopedicsMay 1993

T a b l e V I. M a x i l l a r y r e t ru s io n : c o m m o n f a ci a lc h a r a c t e r i s ti c s o f m a x i l l a r y r e t r u s i o n a r e l i s t e d

Mo.rillary retrusionNormal lower one-thirdNormal interlabial gapNormal incisor exposureNormal smileNo mentalis strainStraight to Class I!I profile angleNormal mandibular sulcus contourIncreased nasal projectionNasal base deficiencyCheekbone/orbital rim deficiencyNormal to increased nasolabial angleNormal throat length

T a b l e V II. M a n d i b u l a r p r o t r u s i o n : c o m m o nf a c i a l c h a r a c t e r i s t ic s o f m a n d i b u l a r p r o t r u s i o na r e l i s t e d

Man dibular prot rus ion (may hav e inc re ase d ve r t i c a lseconda ry to lack o f dental interdigi tat ion)Normal to increased lower one-thirdNormal to increased interlabial gapNormal inciso~"exposureNormal tooth exposure with smileNo increased mentalis strainStraight to Class III profile angleNormal to flat mandibular sulcus contourNormal nasal projection, alar base, and cheekbonesNormal nasolabial angleIncreased throat length

2. Farkas LG. Anthropometry of the head and face in medicine.New York: Elsevier North Holland Inc, 1981.3. Moorrees CFA, Keen M R. N atural head posit ion, a basic con-sideration in the interpretation of cephalomctrie radiog raphs. A mJ Phys Anthropol 1958;16:213-34.4. Wennstrom JL, Lindhe J , Sinclair F, Thilander B. Some peri-odontal tissue reactions to orthodontic tooth movement in mon-keys. J Clin Periodontol 1987;14:121-9.

5. Sadowsky C, Be gole E. Long-tern1 effects of orthodontic treat-ment on periodontal health. AM J ORmO O 1981;80:156-72.6. Wolford LM, lt i l l iard FW, Dugan DJ. Surgical treatment ob-jective. St. Louis: CV Mosby, 1985.7. Legan HL, Burstone CJ. Soft tissue cephalometric analysis fororthognathic surgery. J Oral Surg 1980;38:744-51.8. Burstone CJ . The integumental profile. AM J OR'roOD 1958;44:1-25 .9. Talass MF, Baker RC . Soft tissue profile changes resulting fromretraction o f maxillary incisors. AM J ORTttODDEN'I'OFACOR'HIOP! 987;9 ! (5):385-94.10. Drobocky O B, Sm ith RJ. Changes in facial profile during ortho-dontic treatment with extraction o f four first premolars. AM JORTIIOD DENTOFAC ORTIIOP 1989;95(5):220-30.

I I . Lo FD , Hunter W S. Changes in nasolabial angle related to max-illary incisor retraction. Ar, J OR'roOD 1982;82:384-91.12. tloldaway RA. A soft-tissue cephalometric analysis and its use


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American Journal o f Orthodontics and Dentofacial Orthopedics A r n e l l a n d B e r g t n a n 411~?dume 103, No. 5T a b l e V III . C l a s s I I m a l o c c l u s i o n s c a n b e p r o d u c e d b y m a n d i b u l a r r e t ru s i o n ( m o s t c o m m o n ) , m a x i l l a r yp r o t r u s i o n ( r a r e * ) , o r v e r ti c a l m a x i l l a r y e x c e s s ( c o m m o n ) . ( F a c i a l t r a it s in t h e fa c i al a n a l y s i s o f t h i s ar t i cl ed i s t i n g u i s h a m o n g t h e s e sk e l e ta l p r o b l e m s )

Clas s I I p r o f i le sMan d ibu lar r e t r us ion J M ax i ' laD " r o t r us ion I Ver t i ca l tncL ~ i lla ry exces s

Low er one-third Norm al to decreased (1) Norm al Increasedlnter labia l gap Norm al to decreased (I) Normal IncreasedIncisor exposure Norm al Norm al IncreasedSm i le Norm a l Norm a l G ingivaMen ta l is s tra in Yes (2) Yes (2) YesProfile angle Decreased Norm al to decreased DecreasedM and ibu lar sulcus con tou r Increased (2) Increased (2) IncreasedNasal projec t ion Norm al Normal to short NornmlAlar base Norm al Normal to increased NormalChe e kbone Norm a l Norm a l Norm a lNasolabia l angle Norm al Decreased Norm alThro at length Decreased Norm al Decreased

*Maxil lary d~nta l protrusion is com mon ( i .e . , th umb suck ing) , but t rue maxil la ry basa l bone with denta l protrusion is extremely rare.(1) Decrease d secondary to deep bi te .(2) Upper inc isors impinge on lower l ip and make l ip c losure s tra ined.

T a b l e I X. C l a s s I II m a l o c c l u s i o n c a n b e p r o d u c e d b y m a n d i b u l a r p r o t r u s i o n ( c o m m o n ) , m a x i l l a r y r e t r u si o n( m o s t c o m m o n ) , o r v e r t ic a l m a x i l l a r y d e f i c i e n c y ( r a r e) . ( F a c i a l t r a it s i n t h e f a c i a l a r l al y s i s o f t h i s a r t i c led i s t i n g u i s h a m o n g t h e s e s k e l e ta l p i -o b l e m s )

Class I11 profi lesMan d ibu lar p r o t r us ion J M a~ i l la t ) " e t r us ion J Ver t i ca l m ax i l la r y deficiency

I ILow er one-third Normal to increased (1) Normal DecreasedInter labia l gap Norm al to increased (I) Norm al DecreasedIncisor exposure Norm al Normal DecreasedSmile Norm al Norm al Decreased inc isorMe nta l i s s t r ain None to inc re ase d None None , r e dunda ntProfile angle Stra ight to Class I I I Stra ight to Class I l l Stra ight to Class I I IMa ndibu lar sulcus conto ur Normal to f lat Norm al AccentuatedNa sa l pro je c t ion Norm a l Long Norm a lAlar base Norm al Depressed Norm alChe e kbone s Norm a l F lat Norm a lNasolabia l angle Norm al Norm al to increased Norm al to decreasedThroa t length Increased Norm al Increased

(I) Increased secon dary to lack of denta l interdigitation.

in or thodontic t rea tment planning. Par t I . AM J O R T I I O D1983;84(1):1-28.

13. l loldaway RA. A soft- t issue cephalometf ic analysis and i ts usein or thodontic t rea tment planning. Par t I I . AM J ORTIIOD1984;85:279-93.

14. Oliver BM. The inf luence of l ip thickness and s tra in on upperlip respo nse to inciso r retractio n. A st J ORTIIOD 1982;82(2):141-9.

15. Peck H, Peck S. A concept of fac ia l es the t ics . Angle Orthod1970;40:284-317.

16. Burs tone CJ. Lip posture and i ts s ignif icance in t rea tment plan-ning . AM J ORTIIOD 1967;53:262-84.

17. W orms I"W , Spiedel T M, Bevis RR, Waite DE. Post trea tments tabil i ty and es thet ics of or thognathic surgery. Angle Orthod1980;50(4):251-73.18. Worms FW, Isaacson RJ, Speidel TM . Surgica l or thod ontic trea t-ment planning: prof i le analysis and mandibular surgery. AngleOrtho d 1976;46(1):1-25.

Repr in t r eques t s to :Dr . G . W i l l ia m Arne t t9 E. Pedregosa St.Santa Barbara , CA 93101

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