1-s2.0-S107387460080016X-main

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H e a d g e a r T h e ra p y T h e M o s t E f fic ie n t W a y

t o D i s t a l i z e M o |a r s

AndrewJ Haas

T h i s i s p r i m a r i l y a c l in i c a l a r t i c le , h o w e v e r , s u b s t a n t i v e e v i d e n c e i s p r e s e n t e d

i n c lu d i n g s t u d i e s o f 4 2 a n d 5 8 p a t ie n t s t o s h o w t h e t r e a t m e n t t o b e

u n c o m m o n l y s t a b le . T h e u s e o f K l o e h n c e r v i c a l g e a r i s c o n s i d e r e d i n re g a r d

t o C l a s s II s k e l e t a l c o r r e c t i o n , C l a s s II d e n t a l c o r r e c t i o n , s l o w a p i c a l b a s e

e x p a n s i o n a s a m e a n s f o r c r e a t in g a r c h l e n g t h , a s a n a n c h o r a g e s o u r c e t o

c o r r e c t a n t e r i o r o v e r b i t e , a n d i ts d i re c t a p p l i ca t i o n t o t h e m a n d i b u l a r d e n t a l

a r ch . O w i n g t o t h e g r e a t v e r s a t i l it y a n d e f f e ct i v e n e s s o f t h e a p p l i a n c e , t h e

a u t h o r b e l ie v e s t h a t K l o e h n c e r v ic a l g e a r i s t h e m o s t s i g n i f ic a n t a p p l i a n c e

d e v e l o p e d t o d a t e in o r t h o d o n t i c - o r t h o p e d i c h i s to r y . S e m i n O r t h o d 2 0 0 0 ; 6 :

7 9 - 9 0 . ) C o p y r i g h t © 2 0 0 0 b y W B S a u n d e r s C o m p a n y

D i s ta l iz a t io n o f m o l a r s m a y a s s u m e a n u m b e r

o f f o r m s .

1 . T h e d i r e c t d i st al m o v e m e n t o f t h e u p p e r o r

l o w e r m o l a r s a s i n t h e c o r r e c t i o n o f a d e n t a l

Class I I or Class I I I ;

2 . T h e i n d i r e c t d i s ta l i z a ti o n o f t h e u p p e r m o l a r s

a s a c o n s e q u e n c e o f th e d o w n w a r d a n d b a c k -

w a r d d i s p l a c e m e n t o f th e m a x i ll a in t h e o r t h o -

p e d i c c o r r e c t i o n o f a s k e l e t a l C la s s I I ;

3 . A c o m b i n a t i o n o f 1 a n d 2 w i t h p o s t e r i o r

m o l a r m o v e m e n t w i th in t h e b o d y o f t h e

m a x i l l a , w h i l e t h e m a x i l l a i t s e l f i s b e i n g d i s-

p l a c e d b o d i ly d o w n w a r d a n d b a c k w a r d o n t h e

c r a n i a l b a s e .

D i s t a li z a ti o n o f m o l a r s m a y y e t t a k e a n o t h e r

f o r m a s in t h e u s e o f g r o w t h t o g a in a r c h l e n g t h .

I n t h is i n s ta n c e , t h e m o l a r s a r e m e r e l y h e l d i n

s p a c e w h il e a n t e r i o r t e e t h a n d t h e c o r p u s o f th e

j a w t r a n s la t e s d o w n w a r d a n d f o r w a r d w i th g r o w t h .

P o s t t r e a t m e n t s u p e r i m p o s i t i o n s h o w s a d i st al iz a -

t i o n o f m o l a r s w h e n , i n f a c t , t h e m o l a r s a r e

p r o b a b l y h e l d i n s p a c e w it h in t h e d e n t a l t r o u g h

w h i l e t h e j a w m o v e s f o r w a r d w i t h g r o w t h , t h u s ,

n e e d e d a r c h l e n g t h i s g a i n e d w i t h o u t b u c c a l

t o o t h e x p a n s i o n o r in c i s o r a d v a n c e m e n t , b o t h o f

w h i c h a r e h i g h l y s u s c e p t i b l e t o r e l ap s e .

T h i s a r t i c l e r e v i e w s t h e d i r e c t a n d i n d i r e c t

b e n e f i t s o f th e K l o e h n c e r v i c a l g e a r a p p l i a n c e i n

o r t h o p e d i c a n d o r t h o d o n t i c t r e a t m e n t 1. A n a t-

t e m p t w i ll b e m a d e t o b e o b j e c t iv e , b u t i t w il l b e

d i f f ic u l t n o t t o e x p o u n d h e a r t - f e l t p r e j u d i c e s

r e s u l t i n g f r o m a 4 0 - y e a r l o v e a f f a i r w i t h t h i s

m a r v e l o u s a p p l i a n c e .

A l is t f o ll o w s th a t e n u m e r a t e s , i n t h e a u t h o r s

o p i n i o n , t h o s e i n s ta n c e s i n w h ic h t h e K l o e h n

a p p l i a n c e is c le a r l y s u p e r i o r t o

l l

o t h e r a p p l i -

a n c e s a n d t e c h n i q u e s , a n d w h y i t m i g h t b e t h e

m o s t s i g n i f i c a n t a n d v e r s a t i l e a p p l i a n c e d e v e l -

o p e d i n o r t h o d o n t i c - o r t h o p e d i c h i st o ry .

T h e K l o e h n a p p l i a n c e , i n t h e a u t h o r s o p i n -

i o n , h as n o p e e r i n r e g a r d t o :

1 . C l a ss I I s k e l e t a l c o r r e c t i o n ;

2 . C l as s I I d e n t a l c o r r e c t i o n w i t h n o m a n d i b u l a r

a n c h o r a g e l o s s ;

3 . S l o w a p i c a l b a s e e x p a n s i o n b o t h i n t h e t r a n s -

v e r se a n d a n t e r o p o s t e r i o r (A -P ) d i m e n s i o n ;

4 . A s a n c h o r a g e f o r g a i n in g m a n d i b u l a r a r c h

l e n g t h ;

5 . F o r a n c h o r a g e t o c o r r e c t a n t e r i o r o v e r b it e ;

6 . T o p r o d u c e a g ro w t h - s i m u l a te d t r e a t m e n t i n

a d u l ts i n c l u d i n g p r o v i d i n g a n c h o r a g e i n a

m a x i m u m r e t r a c t io n e x t r a c t i o n c as e;

7 . U s e d d i r e c t l y t o t h e l o w e r a r c h i t is e f f e c t i v e

( a ) f o r C l a ss II I i n t e r c e p t i v e t r e a t m e n t , ( b ) t o

r e s tr a i n l o w e r d e n t a l a r c h a d v a n c e m e n t , a n d

( c ) t o m o v e b u c c a l t e e t h p o s t e r io r l y .

From the University of llinois, C hicago, IL.

Address correspondence to Andrew J. Haas , D DS , MS, 1234

Portage Trail , C uyahoga Falls, OH 44223

Copyright © 2 000 by W..B. Saunders Company

1073-8746/00/0602-0002510. 00/0

doi: O.1053/od. 2000.5900

Seminars in Orthodontics, Vol 6 , No 2 June), 2000 : pp 79-90 79

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8 0 A n d r e w J H a a s

I n d i r e c t b e n e f i t s :

8 . A s a r e s u l t o f t h e w i d e n i n g o f t h e m a x i l l a r y

a p i c a l b a s e , ( a ) a m a n d i b u l a r d e n t a l a r c h

e x p a n s i o n is s p o n t a n e o u s l y i n d u c e d , ( b ) it

c a n a l l ev i at e m a n d i b u l a r p o s t e r i o r a n d l a te r a l

d i s p l a c e m e n t , ( c) it c a n p r o m o t e t e m p o r o -

m a n d i b u l a r j o i n t ( T M J ) h e a l t h , ( d ) i t c a n

p r o m o t e n a s a l re s p i r a t io n , ( e ) it c a n p r o m o t e

g r o w t h o f t h e o r o f a c i a l m u s c u l a t u r e t o fu l l

g e n e t i c p o t e n t i a l .

A s a c o n s e q u e n c e o f t h e d i r e c t a n d i n d i r e c t

b e n e f i t s , a t o t a ll y g r o w t h - r e l a t e d t r e a t m e n t r e s u l t

i s a c h i e v e d , i n b a l a n c e w i t h m a s t i c a t o r y a n d

o r o f a c ia l m u s c l e s, t h u s, l e a d i n g t o i n c o m p a r a b l e

s tab i l i ty .

T h e r e a r e a t l e a s t 1 8 m a j o r r e a s o n s f o r a C la s s

I I d e n t a l r e l a t i o n s h i p . T o g i v e a fe w e x a m p l e s :

( 1) a l l r e l a t io n s h i p s a r e a p p r o p r i a t e e x c e p t t h e

m a x i l l a is s e t f o r w a r d ; ( 2 ) t h e m a x i l l a i s s e t

f o r w a r d a n d t h e m a n d i b l e s e t b a c k ; ( 3) t h e

m a n d i b l e is i n g o o d r e l a t i o n s h i p b u t t h e m a x i l l a

is s o m e w h a t f o r w a r d a n d t h e m a x i l l a r y d e n t u r e

i s a d d i t i o n a l l y f o r w a r d ; ( 4 ) o t h e r v a r i o u s c o m b i -

n a t i o n s w h e r e i n a p o r t i o n o f t h e C l a s s I I i s

s k e l e t a l a n d t h e r e s t is d e n t a l .

S o m e c l i n i c i a n s t r e a t t h e v a s t m a j o r i t y o f t h e i r

C l a ss I I p a t i e n t s w i t h C l a s s II e l as t ic s . T h e r e c a n

b e o n l y o n e C l a ss I I s i t u a t i o n i d e a l l y s u i t e d t o t h e

u s e o f C l as s I I e l a st ic s . T h a t o c c u r s w h e n t h e j a w s

a n d d e n t u r e b a s e s a r e C l as s I , b u t t h e u p p e r

d e n t u r e s e ts f o r w a r d o n i ts b a s e a n d t h e l o w e r

d e n t u r e s e ts b a c k o n i ts ba s e . U n d e r t h e s e

c i r c u m s t a n c e s , d e n t u r e - d i s p l a c i n g C l a ss I I e l as -

t ic s w o u l d b e i d e a l l y s u i t e d . H o w e v e r , u s i n g

e l a s ti c s w h e n o n e o f th e o t h e r 1 7 p o s s i b il i ti e s

e x i st s i s q u e s t i o n a b l e , w i t h o r w i t h o u t e x t r a c t i o n s

b e c a u s e e l a s t i c s h a v e l i tt l e , i f a n y , e f f e c t o n t h e

s k e l e t a l p a t t e r n .

I n r e g a r d t o t h e s k e l e t a l C l a s s I I , a h e a v y

c e r v i c a l g e a r f o r c e o f 2 4 t o 3 2 o z ( 8 0 0 t o 1 , 5 0 0 g )

p e r s i d e c a n c h a n g e t h e A N B a n g l e 6 ° t o 8 ° i n a

p e r i o d o f 1 y e a r .

T h e f i lm s in F i g u r e 1 sh o w d r a m a t i c c h a n g e i n

t h e p r o f i l e a r c t h a t D o w n s 2 d e s c r i b e s a s a n a r c

f r o m n a s i o n t h r o u g h p o i n t A t o p o g o n i o n . T h e s e

a r cs c h a n g e f r o m s e v e re l y c o n v e x , t o t h e i d e a l

m i l d l y c o n v e x , a n d s o m e t i m e s b e y o n d t o s tr a i g h t

o r e v e n m i l d l y c o n c a v e . I n v a r i a b l y , t h e i n c i s o r s

a r e w e l l p o s i t i o n e d i n c l o s e p r o x i m i t y t o t h e

i m p r o v e d a r c , a s n o n e o f t h e p a t i e n t s h a d t e e t h

r e m o v e d . O f t e n s t r a i n e d l i p s a r e o p t i m a l l y r e-

l a x e d i n t h e p o s t t r e a t m e n t f i l m . T h e w r i n k l e d

c h i n s d u e t o t h e n e c e s s i t y to a c t iv a t e t h e m e n t a l i s

m u s c l e t o g a i n l i p c l o s u r e n o w p o s s e s f u l l c o n -

t o ur . T o a c h ie v e s u c h p r o f o u n d p r o f i le c h a n g e s

t h e m a x i l l a is u n i t i z e d w i t h a m a x i l l a r y o r t h o p e -

d i c c r i b, 3 a f o u r - b a n d e d a p p l i a n c e h a v i n g b u c c a l

a n d t r a n s p a l a t a l b a r s s u p p o r t i n g a j a c k s c r ew .

T h e j a c k s c r e w i s a d j u s t e d p e r i o d i c a l l y b y t h e

c l i ni c i an t o p r o m o t e s lo w a p ic a l b a s e d e v e l o p -

m e n t . F i g u r e 2 s h o w s i n t r a o r a l p h o t o g r a p h s o f

a n o r t h o p e d i c C l as s I I p a t i e n t b e f o r e t r e a t m e n t

a n d w i t h 9 m o n t h s o f p ro g r e s s . T h i s r e s u l t is e v e n

m o r e d r a m a t i c t h a n i t a p p e a r s t o b e b e c a u s e t h e

l o w e r m o l a r i s a l s o b e i n g c o n c o m i t a n t l y d i s t a -

l y z e d vi a C l as s I I I e la s t ic s o n l y t o t h e K l o e h n

c e r v i c a l a p p l i a n c e . A c e p h a l o m e t r i c a n a l ys i s i n d i -

c a t es t h a t t h e m a x i l l a h a s b e e n d i s p l a c e d b o d i ly

d o w n w a r d a n d b a c k w a r d , w h i l e t h e p h o t o g r a p h

s h o w s t h a t t h e m o l a r , a s w e l l a s t h e t w o p r e m o -

l a rs , h a v e b e e n d i s t a li z e d w i t h i n t h e b o d y o f t h e

m a x i l la . T h i s r e p r e s e n t s a n e x c e l l e n t e x a m p l e o f

c o m b i n a t i o n d i s t a l i z a t i o n . T h e a u t h o r b e l i e v e s

t h e r e i s n o o t h e r a p p l i a n c e o r t e c h n i q u e t h a t

c o u l d c h a l l e n g e t h e K l o e h n c e r v i ca l i n r e g a r d t o

s k e l et a l C la s s I I c h a n g e a n d i ts a c c o m p a n y i n g

d e n t a l a n d s o f t t i ss u e c h a n g e s . I t a l s o s e e m s t h a t

t e e t h p o s i t i o n e d b y m a n i p u l a t i o n o f g r o w t h a n d

d e v e l o p m e n t h a v e a f a r g r e a t e r c h a n c e f o r s ta b il -

i ty t h a n m e c h a n i c a l l y p o s i t i o n e d t e e t h .

H a a s 4 p e r f o r m e d a s t u d y c o m p a r i n g 4 2 C l as s

I I u n t r e a t e d p a t i e n t s f r o m t h e B o l t o n s t ud y , w i t h

4 3 o f t he a u t h o r s o r t h o p e d i c a l l y t r e a t e d C l as s I I

p a t i e n t s . F o r c e s i n e x c e s s o f 3 0 o z ( 1 , 0 0 0 t o 1 , 5 00

g ) w e r e u s e d i n th e t r e a t e d p a t ie n t s . C e p h a l o m e t -

r i c h e a d f i l m s w e r e o r i e n t e d t o X Y c o o r d i n a t e s

w i t h s e ll a n a s i o n b e i n g t h e X a x is a n d a p e r p e n -

d i c u l a r b i s e c ti n g t h e X a x is t h r o u g h P T M b e -

c a m e t h e Y a x is . F i g u r e 3 A s h o w s t h e e x p e c t e d

g r o w t h o f a n u n t r e a t e d C l as s I I p a t i e n t o v e r a

3 - y e a r p e r i o d . A s L a n d i 5 p o i n t e d o u t , w i t h g r o w t h

N a s i o n , A N S a n d p o i n t A m o v e f o r w a r d a t

a p p r o x i m a t e l y t h e s a m e r a t e , w hi l e P o g o n i o n

m o v e s a b o u t d o u b l e t h a t r a t e . F i g u r e 3 B is th e

t r a c i n g o f t h e p a t i e n t t h a t s h o w e d t h e g r e a t e s t

m a g n i t u d e o f c h a n g e . O v e r a 3 -y e a r p e r i o d ,

N a s i o n a p p e a r s t o h a v e c o m e f o r w a r d a b o u t 2 t o

3 m m a n d , a s e x p e c t e d , t h e u n a f f e c t e d m a n d i b l e

m e a s u r e d a t p o g o n i o n c a m e f o r w a r d 5 to 6 m m .

N o t e t h e l a r g e p o s t e r i o r d i s p l a c e m e n t o f th e

m a x i l la . H a d t h e r e b e e n n o t r e a t m e n t , p o i n t A

a n d A N S w o u l d h a v e a d v a n c e d a p p r o x i m a t e l y 2

t o 3 m m . I t a p p e a r s t h a t t h e s e p o i n t s ( A a n d

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Headgear Therapy to Distalize Molars 8

Figure 1 Three pro fi le changes induced by orthopedic

forc es of 1,000 to 1,500 g pe r side A, B, C).

A N S ) h a v e b e e n m o v e d b a c k 1 0 t o 1 2 m m

b e c a u s e t h e m a x i l l a w a s d i s p l a ce d d o w n w a r d a n d

b a c k w a r d . T h e r e f o r e , t h e n e t c h a n g e i n A N S a n d

p o i n t A i s 1 2 t o 1 4 m m . C o n s i d e r i n g t h a t p o i n t A

w e n t b a c k 12 m m a n d t h e m a n d i b l e c a m e

f o r w a r d 6 m m , i t r e s u l t e d i n a n 1 8 m m d i ff e r -

e n c e i n j a w p o s i t i o n . T h i s i s w i t h o u t a d o u b t a n

o r t h o p e d i c e f f e c t .

A c o m p o s i t e o f t h e 8 5 p a t i e n t s s t u d i e d 4 i s

s h o w n i n F i g u r e 3 C . T h e b r o k e n l i n e s r e p r e s e n t

t h e d i r e c t io n o f m o v e m e n t , a n d t h e l e n g t h o f

l i n e to t h e c ir c l es r e p r e s e n t s t h e m a g n i t u d e o f

c h a n g e d u e t o g r o w t h i n t h e u n t r e a t e d p a t ie n t s.

T h e s o l i d l i n e s r e p r e s e n t t h e d o w n w a r d a n d

b a c k w a r d d i s p l a c e m e n t o f th e s e s a m e p o i n t s i n

t h e o r t h o p e d i c a l l y t r e a t e d p a t i e n t s . T h e d i s t a n c e

b e t w e e n t h e c i r c le s is s t r i k i n g e v i d e n c e o f t h e

e f f e c t i v e n es s o f h e a v y c e r v i c a l g e a r f o r c e . T h i s i s

n o t g r o w t h r e d u c t i o n b u t t h e d o w n w a r d a n d

b a c k w a r d d i s p l a c e m e n t o f th e m a x i l l a r e la t i v e t o

t h e c r a n i a l b a s e . A s e x p e c t e d , t h e d e n t a l p o i n t o f

t h e m e s i a l b u c c a l c u s p o f t h e f i r st m o l a r M B C 6 )

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8 2 AndrewJ Haas

Figure 2. Intraoral ph otogr aphs of a skele ta l Class II

pat ient before t reatment A) and 9 month s in progress

us ing the maxil lary orthope dic crib B).

m o v e d t h e m o s t , a g a in a c o m b i n a t i o n o f th e

m a x i l l a b e i n g d i s t a l i z e d b o d i l y a n d t h e t o o t h

b e i n g a d d i t i o n a l l y d i s t a l i z e d w i t h i n t h e b o d y o f

t h e m a x i l la . T h e s t u d y f u r t h e r s h o w e d e x c e l l e n t

s t ab i li t y o f t h e A P c o r r e c t i o n a n a v e r a g e o f 6

y e a r s a f t e r t r e a t m e n t .

T h e s e c o n d u s e o f K I o e h n c e r v ic a l g e a r n o t e d

w a s f o r d e n t a l c o r r e c t i o n o f a Cl a ss I I m a l o c c l u -

s i o n w i t h o u t l o w e r d e n t a l a r c h d i s p l a c e m e n t .

A n y t e c h n i q u e t h a t r e q u i re s r e c i p r o c a l a n c h o r -

Figure 3. Tracings show the expected growth in an

untr eated Class II fema le over a 3-year peri od A). A

fem ale pa ti en t in the expe r im enta l g roup who dem on-

strated the greatest change o ver a 3-year peri od B).

The co mposi te of 85 pat ients contras t ing the orthope-

dic changes in the experimental sample and the

growth changes in the control grou p in the untreated

sample . The broken l ine represents the direct ion of

mov emen t of cephalometric points, the lengths of

the

l ines indicat ing the m agnitude of the various changes

due to growth. The sol id l ines represe nt the downw ard

and backward displacement of these same points in

orthopedical ly t reated pat ients C).

a g e b e t w e e n t h e t w o d e n t a l a r c h e s t o m o v e

m a x i l l a r y t e e t h p o s t e r i o rl y , w il l a t t h e s a m e t i m e

a d v a n c e t h e l o w e r d e n t u r e . C l as si c e x a m p l e s a r e :

C las s I I e la s t ic s , qua l i fy in g func t i ona l app l ian ces ,

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i . . . . . . = . . . . X AX IS

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Headgear Therapy to istalize Molars

83

t h e H e r b s t a n d s i m i la r b it e j u m p i n g a p p l i an c e s ,

J a s p e r j u m p e r s , 6 a n d o t h e r s. I f t h e d i a g n os i s

i n d i c a t e s t h a t t h e l o w e r d e n t u r e h a s a g o o d t o

i d e a l r e l a t i o n s h i p t o i t s b a s e , o n e m u s t q u e s t i o n

t h e u s e o f t h e s e d e v i c es w h e n l o n g - t e r m s t a bi l it y

s h o u l d b e o u r g o a l . T h e K l o e h n c e r v i c a l f a c e

b o w a p p l i a n c e h a s n o p e e r f o r r e t r a c t i n g o r

h o l d i n g t h e u p p e r d e n t u r e i n s pa c e , w h i le t h e

u n d i s t u r b e d m a n d i b l e a d v a n c e s w i th g r o w t h .

S k el e ta l ly , w h e n t h e j a w s a n d d e n t u r e b a s e s

a r e C l a ss I , a n d a C la s s I I d e n t u r e p a t t e r n e x is t s

o w i n g t o t he u p p e r d e n t u r e b e i n g f o r w a r d , i t

m i g h t b e c o n t e n d e d t h a t t h e u s e o f c e r vi c a l g e a r

c o u l d i n t e r f e r e w i t h m a x i l l a r y g r o w t h . I n t h i s

i n s t a n c e , i t w o u l d n o t b e d e s i r a b l e t o a l t e r

m a x i l l a r y g r o w t h i n a C l a s s I s k e l e t a l p a t t e r n .

H o w e v e r , t h e K l o e h n c e r v i c a l g e a r c a n b e u s e d i n

th i s s i tua t ion . Because low-ra te o r thodont ic fo rces

c a u s e o n ly d e n t o a l v e o l o r c h a n g e s t h e K l o e h n

c e r v i c a l g e a r f o r c e c a n b e v a r i e d a s t h e s i t u a t i o n

d e m a n d s . A s a l r e a d y n o t e d , w h e n t r e a t in g a

seve re ske le ta l C la s s I I , as in F igure 3B, fo rces o f

2 4 t o 4 8 o z o r m o r e a r e g e n e r a t e d , w h e r e a s i f

i m p e d a n c e o f a n t e r i o r m a x i l la r y d e v e l o p m e n t i s

n e e d e d f o r c e s o f 1 6 t o 2 4 o z a r e i n d i c a t e d . I f o n l y

a d e n t o a l v e o l a r f o r c e ( w i th l it t le o r n o e f f e c t o n

m a x i l l a r y g r o w t h ) i s r e q u i r e d , t h e n f o r c e s o f 6 to

10 oz wil l be effect ive .

T h e t h i r d u s e o f t h e K l o e h n c e r v i c a l g e a r i s

f o r a p i c a l b a s e d e v e l o p m e n t . I n t h e a u t h o r ' s

o p i n i o n , i n a m a x i l l a r y d e f ic i e n c y s it u a t i o n , t h e

o b j e ct i ve in o r t h o p e d i c - o r t h o d o n t i c t r e a t m e n t i s

t o p r o m o t e m a x i m u m g r o w th o f t h e m a x i ll a ry

a p i c a l b a s e o r t o i n d u c e g r o w t h o f t h e m a x i l l a r y

a p i c a l b a s e b e y o n d i t s g e n e t i c p o t e n t i a l . F r o m

t h e s t a n d p o i n t o f g n a t h o l o g y , g r o w t h , p h y s i o l -

ogy , t rea tm ent ob jec t ives , and s tab i l i ty , accord ing

t o t h e a u t h o r , t h e f o l l o w i n g s h o u l d b e c o n s i d -

e r e d .

1 . G n a t h o l o g i c a l l y , t h e f r e e d m a n d i b l e s e e k s i ts

m o s t c o m f o r t a b l e , m u s c l e - d e t e r m i n e d , r e st -

i n g , a n d f u n c t i o n a l p o s i t i o n . T h e i m p l i c a t i o n s

i n r e g a r d t o T M J h e a l t h a r e s i g n if i c a n t.

2 . C r e a t i n g a n o p t i m u m e n v i r o n m e n t , f o r t h e

c o n t a i n e d ja w , p r o m o t e s i ts g r o w t h t o i ts fu l l

g e n e t i c p o t e n t i a l .

3 . P hys io log ica l ly , nasa l re sp i ra t ion i s im proved

a s a r e s u l t o f a c o n c o m i t a n t i n c r e a s e i n n a s a l

c a v it y w i d t h . T h e i n c r e a s e d o r a l c a v it y v o l u m e

p r o v i d e s a d d i t i o n a l s p a c e f o r t h e t o n g u e t o

m o v e u p w a r d a n d f o r w a r d o u t o f t h e o r o p h a -

r y n g e a l a r e a . B o t h o f t h e s e e f f e c ts s h o u l d

fac i l i t a t e nasa l re sp i ra t ion .

4 . W h e n t h e w i d t h o f t h e m a x i l l a r y a p i c a l b a s e is

i n c r e a s e d , t h e m a n d i b u l a r t e e t h w i ll f o ll o w ,

d u e t o a l t e r e d m u s c l e b a l a n c e a n d f o r c e s o f

o c c l u s i o n . T h i s o c c u r s i n e v e r y s i tu a t i o n . T h a t

i s, a p e r m a n e n t i n c r e a s e i n m a x i l l a r y a p i c a l

b a s e w i d t h l e a d s to a s p o n t a n e o u s , p e r m a -

n e n t , a n d s i g n i f i c a n t i n c r e a s e i n m a n d i b u l a r

d e n t a l a r c h w i d t h . T h i s w o u l d h a v e a f a v o r -

a b l e e ff e c t o n m a n d i b u l a r a r c h l e n g t h p r o b -

l e m s a n d , u l t i m a t e l y , o n t r e a t m e n t p l a n n i n g .

5 . Vi r tua l ly a l l C la ss I I Div i s ion 2 pa t i en t s , a nd

m os t C las s I I Div i s ion I pa t i en t s , a re in pa r t

f u n c t i o n a l m a n d i b u l a r r e t ru s i on s . T h e f o r m e r

b e c a u s e o f t h e l i n g u a l i n c l i n a t io n s o f t h e

u p p e r c e n t r a l i n ci s or s a n d t h e l a t te r b e c a u s e

o f t h e c o n s t r i c t i o n o f t h e m a x i l l a r y d e n t a l

a r c h , p a r t i c u l a r l y in t h e c a n i n e t o c a n i n e a r e a .

T h e f r e e d m a n d i b l e c a n m o v e f o r w a r d t o

as s is t in the cor rec t io n o f the C las s II . F re -

q u e n t ly , t h i s c a n b e a s m u c h a s o n e h a l f o f a

p r e m o l a r w i d th . 7 T h e e a r l i e r - m e n t i o n e d f ac -

t o r s p r o m o t e a m o r e d e s i ra b l e d i r e c ti o n o f

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

a n d m a x i m i z e g r o w t h o f t he o r o f a c i a l m u s cu -

l a t u r e g i v i n g a f a v o r a b l e e f f e c t o n j a w g r o w t h ,

t o o t h a l i g n m e n t , a n d d e n t o l a b i a l e s t h e t i c s .

F o r t h e s e r e a s o n s , w i d e n i n g t h e m a x i l l a r y

a p i c a l b a s e t o f u l l p o t e n t i a l o r b e y o n d g e n e t i c

p o t e n t i a l i n m a x i l l a r y d e f i c i e n c y p a t i e n t s i s a

v e r y s i g n i fi c a n t o b j e c ti v e a t t a i n a b l e i n o r t h o p e d i c -

o r t h o d o n t i c t r e a t m e n t . R a p i d p a la t a l e x p a n s i o n

(RP E) i s ce r ta in ly a ve ry pos it ive m e tho d o f accom -

p l i sh ing th i s ob jec t ive . In the au thor ' s p rac t i ce ,

a b o u t 2 5 o f p a t i e n t s a r e t r e a t e d w it h R P E , a n d

w i t h a s lo w p a l a t a l e x p a n s i o n i n a t l e a s t 9 5 o f

r e m a i n i n g p a t i e n t s u s i n g t h e K l o e h n c e r v i c a l

a n c h o r a g e f a ce b o w a p p l i a n c e . F ig u r e 4 A a n d B

s h o w s t h e m a x i l l a r y c a s t o f a p a t i e n t ' s t r e a t m e n t

i n p r o g r e s s w i t h 1 6 m o n t h s o f sl o w a p i c a l b a se

e x p a n s i o n b e i n g a c h i e v e d b y m a i n t a i n i n g e x p a n -

s i on o f t h e i n n e r b o w o f t h e K l o e h n a p p l i a n ce .

N o t e t h e 1 2 m m e x p a n s i o n a t t h e u n b a n d e d

s e c o n d b i c u s p i d s . S l o w a p i c a l b a s e e x p a n s i o n

i s p o s s i b l e e v e n i n t h e n o n g r o w i n g p a t i e n t .

Mode ls in F igure 4C and D a re o f an 18½-yea r -o ld

m a n ( C ) a n d 9 y e a rs a ft e r u p p e r H a w l e y r e t e n-

t i o n a n d 7 y e a r s a f t e r al l r e t e n t i o n a t a g e 3 1 ( D ) .

N o t e a su s t a i n e d 5 - r a m w i d e n i n g o f t h e a p i c a l

b a s e . I n t h e t r e a t e d p a t i e n t , w h e n v i e w i n g

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84 Andrew J Haas

Figure 4. Pretreatment A) and progress models B) of a patient in treatment for 16 months with the Kloehn

growth regulator KGR). Pretreatment C) and posttreatment models D) of a patient treated using the KGR in

the absence of growth. Retainers were placed at age 20 and worn for 2 uppers) and 4 lowers) years, respectively.

models, it is virtually impossible to tell the

difference between those patients in whom RPE

was used to widen the apical base and those in

whom slow continuous growth was induced at

the midpalatal and intermaxillary sutures via the

expa nded face bow.

Because of the potential of Kloehn cervical

gear to inhibit forward move men t of the maxilla,

to redirect anteroposterior growth and to pro-

mote transverse, anteroposterior, and vertical

growth, it seems appropriate to refer to the

Kloehn cervical appliance as the Kloehn growth

regula tor KGR). The KGR illustrated in Figure

5 shows a Kloehn face bow that has been altered

to achieve slow maxillary apical base expansion.

The in ner bow has been e xpand ed 8 to 10 mm. If

the bow is kept expan ded thro ugho ut treatment,

significant changes in apical base width, even

rivaling those achieved with rapid palatal expan-

sion, will predictably result. Figure 5B shows

where the outer bow is bent up off the horizon-

tal. The vertical bend in the oute r bow varies

from abo ut 10 ° at the start o f trea tmen t increas-

ing to 25 ° to 30 ° near the end of treatment. The

appliance may be used with or without an ante-

rior buccal shield. The shield might enhan ce the

stretching of the orobuc cal musculature to stimu-

late growth of these struc tures to their full

genetic potential.

When the inner bow is expanded, there is a

definite expansive force delivered to the molars

that would tend to make the molar crowns roll

outwardly. However, this tendency is completely

overcome by the pull of the cervical strap be-

cause the outer bows, whether they are straight

or bent up off the horizonta l, always lie above the

level of the source of the traction force. The

downward force from the outer bows actually

translates to a torque force that would cause the

crowns to roll to the lingual, the net effect being

a bodily lateral force to the molars. Considering

the great anchorage offered by the palatal roots

and period ontal structures and the lesser anchor-

age from the buccal roots, there is a force

transmitted to the intermaxillary and midpalatal

sutures to cause a slow apical base expansion by

7/17/2019 1-s2.0-S107387460080016X-main



Figure 5. The inn er bow of the KGR expan ded 8 to 10

mm wider than the denta l arch A). The pos i t ion a t

which the vert ical bend is mad e on the outer bow B).

Th e buc cal shield version is shown.

s t i m u l a t i n g g r o w t h a t t h e s e s i t e s a n d w i t h c o m -

p e n s a t i n g a d j u s t m e n t s a t a l l o t h e r m a x i l l o c r a n i a l

h a f t i n g s u t u r e s .

T h e a u t h o r b e l i e v es t h a t t h e r e i s n o a c t i v a t o r

o r f u n c t i o n a l a p p l i a n c e c u r r e n t l y i n u se c a p a b l e

o f p r o d u c i n g a n e x p a n s i v e g r ow t h f o r c e t o t h e

m a x i l l a c o m p a r a b l e w i t h t h e K G R . T h e o n l y

a p p l i a n c e t h a t w o u l d e x c e e d t h e a p i ca l b a se

e x p a n s i o n c a p a b il i ty o f t h e K G R i s t h e m a x i m u m

a n c h o r a g e t i s s u e - b o r n e r a p i d p a l a t a l e x p a n s i o n

a p p l i a n c e .

I f th e m a x i l l a r y a p i c a l b a s e i s w i d e n e d , t h e

m a n d i b u l a r t e e t h w i l l f o l l o w . F i g u r e 6 c o m p a r e s

t w o m a n d i b u l a r m o d e l s o f a w o m a n , a g e 1 3 o n

t h e l e ft A ) a n d 1 y e a r l a t e r o n t h e r i g h t B ) . T h e

e x p a n s i o n is a c o n s e q u e n c e o f a l t er e d f o r c e s o f

o c c l u s i o n a n d m u s c l e b a l a n c e . B e c a u s e o f m a x i l -

l a r y a p i c a l b a s e e x p a n s i o n , t h e m a x i l l a r y t e e t h

a r e i n a p e r m a n e n t l y e x p a n d e d p o s i t i o n , t h u s ,

o c c l u s a l c o m p r e s s i n g f o r c e t o t h e l o w e r b u c c a l

t e e t h is d e c r e a s e d a n d t h e m a n d i b u l a r t e e t h w il l

r e s p o n d m o r e r e a d i l y t o t h e a l te r e d m u s c l e

f o r c e s . A s a c o n s e q u e n c e o f t h e m a x i l l a r y a p i c a l

b a s e e x p a n s i o n , t h e b u c c i n a t o r m u s c le s , w h i c h

a t t a c h t o t h e s e b a s es , h a v e m o v e d l a t e r al l y aw a y

f r o m t h e m a n d i b u l a r b u c c a l t e e t h , t h u s, i n e f fe c t

d i m i n i s h i n g b u c c a l m u s c l e p r e s s u r e t o t h e s e

t e e t h a n d , r e l a ti v e l y s p e a k i n g , i n c r e a s i n g l i n g u a l

p r e s s u r e . T h i s s e e m s t o f u r t h e r v a l i d a t e t h e

e q u i l i b r i u m t h e o r y r e g a r d i n g m u s c l e p r e s s u r e

a n d t o o t h p o s i ti o n , s,9 T h e r e w e r e n o o t h e r u p p e r

o r l o w e r a p p l i a n c e s u s e d d u r i n g t h is y e a r. T h e

e x p a n s i o n a t t h e c a n i n e s w a s 3 + r a m , a t t h e f i r s t

p r e m o l a r s 5 m m , a t th e s e c o n d p r e m o l a r s 7 m m ,

a n d a t th e f i r s t m o l a r s 6 r a m . T h e s e c h a n g e s a r e

v e r y st a bl e b e c a u s e t h e y w e r e i n d u c e d b y p e r m a -

n e n t l y a l t e r e d n a t u r a l f o r c e s . F i g u r e 7 s h o w s t h e

case o f a 19-yea r-o ld m an a t the s t a r t o f a

t r e a t m e n t t h a t w as i n i a t e d b y R P E a n d 2 0 .5 y e ar s

a f t e r l i n g u a l r e t e n t i o n . N o t e t h e o b v i o u s l y s t a b l e

3 - m m e x p a n s i o n f r o m a p p r o x i m a t e l y 2 2 t o 2 5

m m a t c a n i n e c u s p t ip s .

M a n y o r t h o d o n t i s t s w h o h a v e t r e a t e d a p a -

t i e n t w i t h C l a s s I I D i v i s i o n 2 m a l o c c l u s i o n b y

ch ang ing i t to a C las s I I Div i s ion 1 by s im ply

t i p p i n g t h e u p p e r c e n t r a l i n c i s o r s f o r w a r d c o n -

t e n d t h a t t h ey h av e o b s e r v e d t h e m a n d i b l e m o v e

f o r w a r d a s m u c h a s o n e h a l f a p r e m o l a r w i d th .

W r i g h t 7 c l a i m e d t h a t t h e l a t t e r o c c u r r e d v i r t u a l ly

e v e r y t i m e , a n d t h e a u t h o r c o n c u rs . T h e a u t h o r

a ls o b e l ie v e s t h a t t h e s a m e p h e n o m e n o n o c c u r s

i n t h e C l a ss I I D i v i s io n 1 m a l o c c l u s i o n t r e a t m e n t .

T h e c o m p r e s s e d o r V - s ha p e d m a x i l la r y a rc h ,

p a r t i c u l a r l y i n c o n j u n c t i o n w i t h a d e e p a n t e r i o r

o v e r b i t e , c o u l d r e s u l t i n a p o s t e r i o r d i s p l a c i n g

f o r c e t o t h e m a n d i b l e . W i d e n i n g t h e m a x i l l a r y

a p i c a l b a s e, a s p r e v io u s l y n o t e d , f r e e s t h e m a n -

d i b l e a n d i f i t w e r e p o s t e r i o r l y d i s p l a c e d i t m a y

Figure 6. S ignificant expansion of the lower denta l

arch in response to a l tered m uscle and occlusal forces

after 1 year of t reatmen t to the maxil lary arch.

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8 6 Andrew J Haas

Figure 7. Pretreat ment ma ndibula r cast (A) and 20.5

years out o f re tent ion, (B) confirm ing a 3-ram s table

expansion.

m o v e f o r w a r d t o p a r t i a l l y c o r r e c t t h e C l a s s I I

m o l a r r e l a t i o n s h i p , t h e r e b y f a c i l i t a t i n g t r e a t -

m e n t . I t w o u l d s e e m t h a t m a n y C l as s I I p a t i e n t s

w h e t h e r D i v i s i o n 1 o r D i v i s i o n 2 , a r e f u n c t i o n a l

m a n d i b u l a r r e t r u s i o n s a n d , t h u s , b e n e f i t g r e a t l y

f r o m t h e f r e e d o m a f f o r d e d t h e m a n d i b l e a s a

r e s u l t o f t h e m a x i l l a r y c h a n g e .

A c c o r d i n g t o t h e a u t h o r , c o m p r e h e n s i v e o r -

thodontics , which includes skele ta l or denta l Class

I I c o r r e c t i o n a n d o r t h o p e d i c m a x i l l a r y a p i ca l

b a s e e x p a n s i o n , p r o m o t e s a f a v o r a b l e d i r e c t i o n

o f m a s t i c a t o r y a n d o r o f a c i a l m u s c l e a c t i o n . I n

a d d i t i o n , t h e g r o w t h o f t h e o r o f a c i a l m u s c u l a -

t u r e a n d l i p s i s s t i m u l a t e d t o t h e i r f u l l g e n e t i c

p o t e n t i a l . T h e l a t t e r l e a d s t o th e o p t i m a l e n v i r o n -

m e n t f o r j a w g r o w t h , t o o t h a l i g n m e n t , d e n t o l a -

b ia l e s the t i c s, and , m os t im p or tan t ly , s t ab il i ty .

T h e f o u r t h b e n e f i t n o t e d , w a s th e u s e o f K G R

a s a n c h o r a g e f o r g a i n in g m a n d i b u l a r a r c h l e n g t h.

F i g u r e 8 s h o w s t h e m e c h a n i c s t h a t a r e u s e d . F o u r

m o l a r b a n d s a r e p la c e d , t h e u p p e r m o l a r s r e-

c e i v e t h e K G R , a n d t h e l o w e r m o l a r s v i a . 0 4 5

b u c c a l t u b e s p r o v i d e a t t a c h m e n t f o r a n . 0 22

a r c h w i r e s u p p o r t i n g s l i d i n g h o o k s v i a o p e n c o i l

s p r i n g s . T h e a r c h i s l i g a t e d t o t h e i n c i s o r s a n d

s t o p p e d a t t h e c a n i n e a r e a . T h e c o i l s p r i n g s a r e

a c t i v a t e d p e r i o d i c a l l y b y e x t e n d i n g t h e m . C l as s

I I I el a st i cs a r e w o r n o n l y w h e n t h e h e a d g e a r is

worn . P a t i en t s a re s een a t 10-week in te rva l s .

F igures 9A, B , C , and D a re ac ry l i c m od e l s o f a

1 2 - y ea r - ol d g ir l a f t e r 1 4 m o n t h s o f t r e a t m e n t .

T h i s p a t i e n t w a s s e e n o n l y 6 t i m e s d u r i n g t h e

1 4 m o n t h t r e a t m e n t . N o t e t h e b i te o p e n i n g f r o m

p r e t r e a t m e n t ( F ig 9 A ) t o l a t e r ( F i g 9 B ) a n d t h e

C l a s s I b u c c a l t o o t h c o r r e c t i o n ( F i g 9 B ) . F i g u r e

9 D s h o w s t h e n e a r - p e r f e c t l o w e r i n c i s o r a l i g n -

m e n t c o m p a r e d w it h p r e t r e a t m e n t ( Fi g 9 C ) . T h e

i n c i s o r c h a n g e w a s b e c a u s e o f s p a c e a c c u m u l a -

t i o n a n d t h e t e e t h b e i n g t i e d t o t h e a r c h w i r e in a

m a n n e r t o c o r r e c t r o t a t i o n s . A l s o o f i n t e r e s t is

t h e f ac t t h a t t h e lo w e r u n h a n d e d s e c o n d p r e m o -

l a r t e e t h e x p a n d e d 3 .5 m m ( F ig 9 C , D ) . T h e

u p p e r i n c i s o r s w e r e m o l d e d b y o c c l u s a l f o r c e s

f r o m t h e l o w e r i n c i s o r s a n d l i p m u s c l e p r e s s u r e s

a n d t h e u n r a v e l i n g a n d t e n s i o n o f t h e t r a n s e p t a l

f i b e r s . F i g u r e 9 D f u r t h e r s h o w s t h e t r a n s v e r s e

d e v e l o p m e n t o f t h e m a x i l l a r y a p i c a l b as e , i nd i c a t-

i n g a 6 m m c h a n g e a t t h e u n b a n d e d u p p e r

s e c o n d p r e m o l a r s ( F i g 9 E , F ) . I n F i g u r e 9 G a n d

H , a l s o n o t e t h e a n t e r o p o s t e r i o r i n c r e a s e i n t h e

a p i c a l b a s e . M e a s u r i n g f r o m t h e i n c i s i v e p a p i l l a

t o t h e f i r s t m o l a r s t h e r e w a s a 4 m m i n c r e a s e .

T h e s e c h a n g e s o c c u r r e d i n 1 4 m o n t h s , w i t h 4

m o l a r b a n d s , a p r e f o r m e d l o w e r a r c h w i r e , a n d

o n l y 6 v i s i t s , w i t h t h e o n l y a p p l i a n c e m a n i p u l a -

t i o n r e q u i r e d b e i n g a n o c c a s i o n a l i n t r a o r a l a dj u st -

m e r i t t o l e n g t h e n t h e c o i l s p r i n g s. T h i s t r e a t m e n t

o u t c o m e is r e p r o d u c i b l e o n a n y c o o p e r a t i v e , g r o w -

i n g c h i l d . T h i s p a t i e n t w o r e a n t e r i o r b a n d s f o r 4

Figure 8. The appliance for mainta ining buccal tee th

in space while the corpus of the mandible advances

with growth.

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Figure 9. The changes on a simulated wax set-up occurring in 14 months using growth to create space in the

anteropost erior and transverse dimensions A-H) see text for details).

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8 8 AndrewJ Haas

m o n t h s , w i t h t h e t o t a l a c t i v e t r e a t m e n t t i m e o f

1 8 m o n t h s .

T h e r a t i o n a l e b e h i n d t h is t r e a t m e n t i s t h e

r e c o g n i t i o n t h a t t h e t o t a l f a c e g r o w s ( o r d i s -

p l a c e s ) d o w n w a r d a n d f o r w a r d , c a r r y i n g a ll s t r u c -

t u r e s in t h a t d i r e c t io n . I f t h e u p p e r a n d l o w e r

b u c c a l t e e t h a r e h e l d i n s p a c e , a l l o t h e r s t r u c -

t u r e s c o n t i n u e t o m o v e d o w n a n d f o r w a r d ,

e s p e c i a l l y t h o s e o f p a r t i c u l a r i n t e r e s t , t h e c o r p u s

o f t h e j a w s a n d t h e i n c i s o r s . G r o w t h i s, t h e r e f o r e ,

t h e m e c h a n i s m b y w h i c h s p a c e i s c r e a t e d t h r o u g h -

o u t t h e a r c h e s , a n t e r i o r t o t h e m o l a r s . W h a t

b e t t e r w a y t o r e so l v e a n a r c h l e n g t h p r o b l e m

t h a n t o h a v e t h e p a t i e n t g r o w i n t o s u f f i c ie n t

s p a c e f o r id e a l t o o t h a l i g n m e n t ? I n a r e c e n t

s t u d y 1° o f 5 8 p a t i e n t r e c o r d s t h a t w e r e e q u a l l y

d i v i d e d i n t o p a t i e n t s w h o h a d r a p i d p a l a t a l

e x p a n s i o n a n d t h o s e w h o h a d s lo w p a l a t a l e x p a n -

s i on i n d u c e d b y t h e K G R , i t w a s f o u n d t h a t t h e r e

w e r e n o s i g n i f i c a n t d i f f e r e n c e s b e t w e e n t h e 2

m e t h o d s . B o t h m e t h o d s w e r e a ls o f o u n d t o b e

v e r y st a bl e . A l l p a t i e n t s u n d e r w e n t a r c h l e n g t h

g a i n i n g t r e a t m e n t u s i n g t h e K G R to h o l d b u c c a l

t e e t h i n s p a c e w h i l e t h e j a w s a n d d e n t u r e b a s es ,

c a r r y i n g i n c is o rs , g r e w f o rw a r d . T h e o r t h o d o n t i c

s t a b il i ty o f t h e p a t i e n t s w a s a l s o e x c e l l e n t : N o n e

o f t h e 5 8 p o s t r e t e n t i o n r e c o r d s m e a s u r e d i n th is

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

s t a n d a r d s e s t a b l i s h e d i n t h e L i t t le i r r e g u l a r i t y

i n d e x c a t e g o r i e s . T h i s s e e m s t o e s t a b l i s h a n e w

s t a n d a r d f o r s t a b il i ty o f C l a s s I n o n e x t r a c t i o n

t r e a t m e n t c o m p a r e d w i th p r e v i ou s ly p u b l is h e d

a r t i c le s c o n c e r n i n g r e l a p s e i n t h e l i t e r a t u r e . '' 1°

T h e p a t i e n t s a v e r a g e d 8 y e ar s p o s t r e t e n t i o n .

A r g u a b l y , t h e r e a l s o c o u l d b e n o b e t t e r w a y t o

c o r r e c t a d e e p a n t e r i o r o v e r b i t e t h a n h a v i n g t h e

p a t i e n t g r o w i n t o a n i d e a l o v e r b i t e .

T h e f if th b e n e f i t r e g a r d i n g t h e u s e o f t h e K G R

i s a s a n c h o r a g e t o c o r r e c t a n t e r i o r o v e r b i t e .

F i g u r e 1 0 s h o w s a 1 7 × 2 5 l e v e r a r c h s p a n n i n g

f r o m t h e m o l a r s t o t h e i n c is o r s . T h e r e i s a

r e v e r s e g a bl e b e n d p l a c e d i n f r o n t o f th e m o l a r s

t o e l e v a t e t h e a r c h i n t o t h e a n t e r i o r v e s t i b u l e .

W h e n t h is a r c h i s s e a t e d i n t h e i n c i s o r b r a c k e t s , a

t o r q u i n g a n d d e p r e s s i n g f o r c e i s a p p l i e d t o t h e

i n ci s or s . T h e a m o u n t w o u l d b e e q u a l t o t h e

a n g l e o f t h e g a b l e b e n d , i e , i f t h e g a b l e b e n d s a r e

3 0 ° t h e n t h e i n c i s o r s w o u l d r e c e i v e a 3 0 ° t o r q u e

f o r c e . T h i s s a m e l e v e r a r c h w o u l d a l s o p l a c e a

t i p p i n g f o r c e o n t h e m o l a r . B e c a u s e p o s t e r i o r

t i p p i n g o f th e m o l a r i s m u c h m o r e e a si ly a c c o m -

p l i s h e d t h a n a n t e r i o r i n c i s o r d e p r e s s i o n a n d

F ig u re 1 0 . M ech an ics u sed fo r d ep res s io n o r p rev en -

t i o n o f e ru p t io n s o f u p p e r i n c i so r s fo r o v e rb i t e co r r ec -

tion.

t o r q u e , i t i s, t h e r e f o r e , n e c e s s a r y t o p r e v e n t t h e

m o l a r t i p p i n g s o th a t t h e d e s i r e d a n t e r i o r f o r c e s

i n t h e a r c h w i r e m i g h t b e e x p r e s s e d . T h i s i s

a c c o m p l i s h e d b y b e n d i n g t h e o u t e r b o w s o f t h e

f a c e b o w u p w a r d s o t h a t t h e p u l l o f t h e n e c k

s t r a p w il l p u t a d i s t a l r o o t t h r u s t o n t h e m o l a r s .

W h e n t h e K G R i s a c t i v a t e d t h e r e i s a l if t p r o -

d u c e d o n t h e a n t e r i o r o f t h e f a c e b o w t h a t c a n b e

a d v a n t a g e o u s l y u s e d t o i m p l e m e n t t h e d e p r e s -

s i o n a n d t o r q u e o n t h e a n t e r i o r t e e t h b y p l a c i n g

a c a n i n e t o c a n i n e e l a s ti c o n t h e i n n e r b o w o f t h e

K G R . T h e e l a s ti c c r a d l e s t h e i n c i s o r s s y n e r g i z i n g

t h e e f f e c t s o f t h e a r c h w i r e . T h e e l a s ti c p u l ls t h e

b o w d o w n w a r d a w a y f r o m t h e u p p e r l ip , w h i le a t

t h e s a m e t i m e i n c r e a s e s t h e a n t e r i o r d e p r e s s i n g

a n d t o r q u i n g a c t iv i ty o f th e a r c h w i r e . D e n t o l a -

b i a l e s t h e ti c s is s u p e r i o r w h e n i n c i s o r s a r e p r e -

v e n t e d f r o m e r u p t i n g o r a r e d e p r e s s e d , i n c on -

t r a s t t o b i t e o p e n i n g p r o c e d u r e s t h a t r e s u l t i n a n

o v e r e r u p t i o n o f p o s t e r i o r t e e t h . T o o p e n t h e b i te

b y e r u p t i n g p o s t e r i o r t e e t h c a n l e a d t o r e l a ps e

d u e t o t h e i n f r i n g e m e n t o f th e s e t e e t h i n t o t h e

m u s c l e - d e t e r m i n e d f r e e w a y s p a ce 2 1

T h e s e m e c h a n i c s o f u s i n g t h e K G R c a n a l s o b e

a p p l i e d t o p r o d u c e a g r o w t h - s i m u l a t e d t r e a t -

m e n t i n a d u lt s . I f t h e i n c i s o r s c a n n o t b e a d -

v a n c e d w i t h g r o w t h , t h e n o b v io u s ly , a l l o r s o m e

o f th e b u c c a l t e e t h m u s t b e m o v e d p o s t e r io r ly .

T h e r e f o r e , i n t h e a b s e n c e o f g r ow t h , i t i s a l m o s t

a lw a ys n e c e s s a r y t o r e m o v e t e e t h w h e n a n e e d

f o r s i g n i f ic a n t a r c h l e n g t h e x i s ts . E x t r a c t e d t e e t h

m a y b e p r e m o l a r s o r c o m p r o m i s e d f i rs t, s e c o n d ,

o r t h i r d m o l a r s . T h e m a j o r i t y o f a du l t s t r e a t e d

h a v e a l re a d y h a d t h i r d m o l a r s r e m o v e d .

F i g u r e 1 1 s h ow s a u n i q u e p a t i e n t i n o r t h o d o n -

t ic s , t h a t o f a 3 5 - y e a r - o l d w o m a n , I t s h o w s t h e

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Headgear Therapy to istalize Molars

89

Figure 11. The pretreatment cast of a 35-year-old

woman with a severe Class III dental occlusion (A). The

posttreatment casts showing great change particularly

in the relationship of the second molars (B). Maxillary

and mandibular superimpositioning to show the tooth

rnovement in both dental arches (C).

S A

1 1 1 7 8 9

3 2 5 9 2 . . . . . . . . .

sixth and seventh uses of the KGR. The sixth use

is a growth-simulated treatment in the adult, the

seventh being the application of the face bow

directly to the mandible to distalize molars and

other buccal teeth in the growing or nongrowing

individual. The author believes that this treat-

ment is unique but that it can be reproduced.

Because few orthodontists apply cervical traction

to the mandibular dental arch and even fewer

would do so expecting to move molars more

than 5 mm, the patient shown is of considerable

interest. It had been the intent to be less heroic

by removing lower first premolar teeth but the

patient asked whether it was possible to move

teeth into the space previously occupied by the

much earlier extraction of her third molars.

Figure l lA shows the severe lower anterio r

crowding as well as a full Class III molar relation-

ship with a crossbite extending from the second

premo lar to the second molar. The patient s

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9 0 AndrewJ Haas

r i g h t s i d e w a s a m i r r o r i m a g e o f t h e l e f t s i d e , s o

t h a t s h e h a d a s e v e r e b i l a t e r a l c r o s s b i t e .

T h e b i l a t e r a l c ro s s b i t e w a s c o r r e c t e d b y a

n o n s u r g i c a l s e m i r a p i d p a l a t a l e x p a n s i o n . A t i ss u e -

b o r n e m a x i m u m a n c h o r a g e a p p l i a n c e w a s c o m -

f o r t a b l y e x p a n d e d t o 14 m m o v e r a 3 - m o n t h

p e r i o d o f t im e . A t th e s a m e t i m e , t h e l o w e r

m o l a r s w e r e d i s t a l i ze d b y d i r e c t a p p l i c a t i o n o f

t h e K G R t o t h e l o w e r f i r st m o l a r s . T h e r e s u l ts o f

t h e s e m e c h a n i c s c a n b e s e e n i n F i g u r e l l B . T h e

t r e a t m e n t w a s a c c o m p l i s h e d i n 2 6 m o n t h s .

T h e s u p e r p o s i t i o n s ( F i g 1 1 C ) d r a m a t i c a l l y c o n -

f i r m t h a t f i rs t a n d s e c o n d m o l a r s w e r e d i s t a l i z e d

b o d i l y a p p r o x i m a t e l y 5 m m o r m o r e p e r s i de .

U p p e r m o l a r s m a i n t a i n t h e i r a n t e r o p o s t e r i o r

p o s i t i o n w i t h s e c o n d m o l a r i n t r u s i o n . T h e r e w a s

a m o d e s t f o r w a r d t i p p i n g o f b o t h u p p e r a n d l o w e r

i n ci so r s. T h e e n t i r e a n t e r o p o s t e r i o r c o r r e c t i o n w a s

m a d e b y m o v i n g t h e l o w e r b u c c a l t e e th p o s te r io r ly .

onc lu s ion s

I t i s h o p e d t h a t t h i s a r t i c l e w i l l p r o v i d e e v i d e n c e

t h a t p r o p e r l y u s e d K l o e h n c e r v i ca l h e a d g e a r i s

n o t c o n s t ri c t iv e , n o r i s i t c a p a b l e o f e l i m i n a t i n g

g r o w t h o r c a u se T M D p r o b l e m s . O n t h e c o n t r a r y

K l o e h n c e r v i c a l h e a d g e a r c a n b e e x p a n s i v e to

t h e m a x i l l a r y a p i c a l b a s e a n d t o b o t h d e n t a l

a r c h e s . In a d d i t i o n , w i t h a d e q u a t e f o r c e t h e

e n t i r e m a x i l l a c a n b e d i s p l a c e d p o s t e ri o r l y, d o w n

a n d b a c k , o n t h e c r a n i a l b a s e , t o g i v e a v a s tl y

i m p r o v e d a n t e r o p o s t e r i o r j a w a n d d e n t u r e r e la -

t i o n s h i p i n t h e s k e l e t a l C la s s I I p a t i e n t .

I t s e e m s t h a t t h e K l o e h n c e r v i c a l g e a r a p p l i -

a n c e c a n p l a y a s i g n i f ic a n t ro l e i n o r t h o d o n t i c

m e c h a n o t h e r a p y . T h e p o p u l a r i t y o f t h e f u nc -

t i o n a l a p p l i a n c e is r a p i d l y d i m i n i s h i n g . T h e

s o - c a ll e d n o n c o m p l i a n t a p p l i a n c e s a n d t e c h -

n i q u e s a r e e s s e n t ia l l y d e n t a l e x p a n s i o n a p p l i -

a n c e s . T h o s e w i t h r e c i p r o c a l a n c h o r a g e h a v e

b e e n s h o w n t o d i sp l a c e t h e m a n d i b u l a r a n c h o r -

a g e . 6 O r t h o d o n t i c h i s t o r y a n d r e s e a r c h h a s s h o w n

t h a t e x p a n d i n g t e e t h i n t o m u s c u l a t u r e i n v it e s a n

e x t r e m e l y h i g h i n c i d e n c e o f r e l a p s e . 8,9

C h a n g i n g a s o u n d t r e a t m e n t p l a n , b a s ed o n

b i o l o g i c a l p r i n c i p l e s w i th e x c e l l e n t p r o g n o s i s f o r

s t a b i l it y t o o n e w i t h a q u e s t i o n a b l e c h a n c e f o r

s t a bi l it y t o a c c o m m o d a t e t h e n o n c o o p e r a t i v e

p a t i e n t s h o u l d b e r e j e c t e d . R a t h e r t h a n c h a n g -

i n g t h e t r e a t m e n t p l a n i t i s s t r o n g l y s u g g e s t e d

t h a t th e o r t h o d o n t i s t c h a n g e s t h e p a t i e n t t o b e

c o o p e r a t i v e . T h e a u t h o r s r e s u l ts p r o v e t h a t t h e

l a t t e r i s p o s s i b l e .

F i n a ll y , i t i s h o p e d t h a t t h e e v i d e n c e p r e s e n t e d

w i ll c o n v i n c e t h e r e a d e r t o a g r e e o r a t l e a s t a c c e p t a

p o s i t i o n o f n o n c o n t e n t i o n t h a t t h e K G R is t h e

m o s t s i g n i f ic a n t a n d v e r s a ti l e a p p l i a n c e d e v e l-

o p e d i n o r t h o d o n t i c - o r t h o p e d i c h i st o ry .

References

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