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A N N A L S O F H U M A N B I O L O G Y , 1976, VO L. 3, N O . 5 , 4 1 1 - - 4 2 1

N e w s y s t e m s f o r d e n t a l m a t u r i ty b a s e d o n se v e n a n df o u r t e e t h

A . D E M I R J I A NC e n t r e d e R e c h e r c h e s u r l a C r o i s sa n c e H u m a i n e , U n i ve r si tO d e M o n t r e a l

a nd H . G O L D S T E I NN a t i o n a l C h i l d r e n ' s B u r e a u , L o n d o n

[Rece ived 19 March 1976]Summary . A n u p d a t e d s y s t e m f o r e s t i m a t i n g d e n t a l m a t u r i t y i sp r e s e n t e d . I t e x t e n d s t h e o r i g i n a l s y s t e m ( D e m i r j i a n e t a l . , 1973)b a s e d o n r a d i o g r a p h s o f 7 t e e th b y i n c l u d i n g t w o e x t r a s ta g e s, a n d b ye n l a r g i n g t h e s t a n d a r d i z i n g s a m p l e t o in c l u d e 2 4 0 7 b o y s a n d 2 3 49g i rl s. P e r c e n t i le s t a n d a r d s f r o m a g e s 2 . 5 t o 1 7 - 0 y e a r s a r e p r e s e n t e ds e p a r a t e l y f o r b o y s a n d g i r l s .

S c o r i n g s y s t e m s a n d p e r c en t i le s t a n d a r d s a r e p r e s e n t e d f o r t w od i f f e r e n t s e ts o f 4 t e et h a n d a c o m p a r i s o n o f al l t h r e e s y s t e m s ism a d e . I t i s s u g g e s t e d t h a t t h e s e s y s t e m s m a y m e a s u r e s o m e w h a td i f f e r e n t a s p e c t s o f d e n t a l m a t u r i t y .

i . IntroductionI n a n e a rl i e r p a p e r (D e m i r j ia n , G o l d s t e i n a n d T a n n e r , 1 97 3) a n e w m e t h o d f o r

a s s es s in g d e n ta l m a t u r i t y w a s d e s c r ib e d . I t w a s b a s e d o n r a t i n g s o f r a d i o g r a p h s o ft h e s e v e n l e f t s i de t e e th o f t h e m a n d i b l e , w h i c h w e r e s h o w n t o b e r e p r e s e n t a t i v e o f a llt h e t e e t h o f t h e m a n d i b l e . E i g h t s t a g e s o f c a l c i f ic a t i o n f o r e a c h t o o t h w e r e i d e n t i fi e da n d d e s c r i b e d a n d e a c h o n e w a s a l l o c a t e d a s c o r e . T h e s u m o f t h e s e s c o re s f o r a ni n d i v i d u a l p r o v i d e s a n e s t i m a t e o f d e n t a l m a t u r i t y o n a s c al e m e a s u r i n g f r o m 0 t o 1 0 0.S c o r e s a n d p e r c e n t i l e s t a n d a r d s w e r e g i v e n s e p a r a t e l y f o r b o y s a n d g i r ls f o r t h e a g er a n g e 3 - 1 6 y e a r s . T h e m a t h e m a t i c a l t e c h n i q u e u s e d t o c a l c u l a t e t h e s c o r e s f o r t h es t a ge s is t h e s a m e a s h a s b e e n u s e d f o r th e m e a s u r e m e n t o f s k e l et a l m a t u r i t y ( T a n n e r ,W h i t e h o u s e , M a r s h a l l , H e a l y a n d G o l d s t e i n , 1 97 5), a n d a d e t a i l e d d e s c r i p t i o n i sg i v e n b y H e a l y a n d G o l d s t e i n ( 1 9 7 6 ) .

T h i s e a r l i e r s y s t e m h a d t w o m a i n s h o r t c o m i n g s . F i r s t, r a t i n g s o f a ll s e v e n t e e thn e e d e d t o b e m a d e . I n m a n y o l d e r c h il d r e n h o w e v e r , o n e o r m o r e t e e t h a r e m i ss i n g ,n o r i s i t a l w a y s p o s s i b l e t o u s e th e c o r r e s p o n d i n g t o o t h f r o m t h e r i g h t s id e o f t h em a n d i b l e . A l s o , f o r p r a c t i c a l r e a s o n s , i t i s o f t e n s i m p l e r t o t a k e a r a d i o g r a p h o ff e w e r th a n s e v e n te e t h , s o t h a t t h e r e i s s o m e p u r p o s e i n s t u d y i n g s y s t e m s b a s e d o nf e w e r t e e th . N a t u r a l l y s o m e i n f o r m a t i o n a n d p r e c i s i o n i s l o s t i n t h e p r o c e s s a n d s u c hs y s t e m s m a y b e m e a s u r i n g s li g h tl y di f fe r e n t c o m p o n e n t s o f d e n t a l m a t u r i t y .

T h e s e c o n d l i m i t a t i o n o f t h e e a r l ie r s y s t e m w a s t h e a b s e n c e o f s u f fi c ie n t n u m b e r so f v e r y y o u n g a n d v e r y ol d c h il d r en in th e s t a n d a r d i z i n g s a m p l e . T h i s m e a n t t h a t t h ee a r l y s t a g e s o f s o m e t e e t h c o u l d n o t b e i n c l u d e d s i nc e t h e y w e r e i n s u f f ic i e n tl y

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412 A , D e m i r j i a n a n d H . G o l d s t ei nrepresented in the sample, and that percentile standards could not be provided forthe extreme age groups.

The purpose of the present paper is to present new seven-tooth systems whichextend the age range and the number of stages, and also to present two new four-toothsystems.

2 . M a t e r i a l s a n d m e t h o d sA full description of the tooth rating system is given by Demirjian et a l . (1973).

Briefly, this consists in identifying eight stages of calcification for each tooth, rangingfrom the calcification of the tip of a cusp to the closure of the apex. The stages arelabelled 0 for no calcification and A to H for the 8 calcification stages. Panoramicradiographs were obtained from a standardizing sample of 1446 boys and 1482 girlsaged 2-20 years of French-Canadian origin.

Age Boys Girls Total0.0- 2-5 27 23 502-5- 3.5 115 72 1873.5- 4.5 171 146 3174.5- 5.5 198 157 3555.5- 6.5 223 194 4176.5- 7.5 147 135 2827.5- 8.5 111 120 2318.5-9.5 148 167 3159.5-10.5 223 208 43110.5-11,5 114 130 24411.5-12.5 193 170 36312.5-13.5 234 239 47313.5-14.5 183 215 39814-5-15.5 123 157 280~5.5-16-5 134 166 30016.5-17-5 57 48 10517.5-20.0 6 2 8

Total 2407 2349 4756Table l, Numberof children at each age.

The sample has now been increased to 2407 boys and 2349 girls (Table 1). This hasallowed us to include two stages which were excluded in the earlier system, namelystage A of the first premolar (PMI) and stage C of the first incisor (10. It has alsoallowed us to include 3rd and 97th percentile estimates for the maturity standards.

Where panoramic radiographs can not be used, two periapical radiographs of themolars and premolars may be taken. We have therefore considered these four teethas a separate system (M2, Ml, PM2, PM~) for which scores and standards will bepresented. The development of the lower central incisor being chronologically almostthe same as for the first molar, in older age groups where this latter is often missingthe central incisor has been assessed instead of the molar. This is the reason why wealso present separate scores and standards for this group of four teeth (M2, PM2,PM1, I1). In this case an additional periapical film of the incisor area is required. Inall three systems we have used equal "biological" weights for each tooth (see Demirjianet a l . , 1973).

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.

N ew sy s t ems fo r den ta l ma tur i tyResu l t sThe maturity scores for the three systems are given in tables 2-4.

413

Boys StagesTo ot h 0 A B C D E F G H

Mz 0.0 1.7 3.1 5.4 8.6 11.4 12.4 12.8 13.6Ml 0. 0 5.3 7.5 10.3 13.9 16.8PM2 0.0 1.5 2.7 5.2 8.0 10.8 12.0 12.5 13,2PM~ 0.0 4.0 6.3 9.4 13.2 14.9 15.5 16.1C 0.0 4.0 7.8 10.1 11.4 12.0lz 0.0 2.8 5.4 7.7 10.5 13.21~ 0- 0 4-3 6-3 8- 2 11"2 15-1Girls

StagesTo ot h 0 A B C D E F G H

M2 0.0 1.8 3.1 5.4 9. 0 11.7 12.8 13.2 13.8M~ 0.0 3.5 5.6 8.4 12.5 15.4PM2 0.0 1.7 2.9 5.4 8.6 11.1 12.3 12.8 13.3PM~ 0. 0 3. t 5.2 8.8 12-6 14.3 14.9 15.5C 0.0 3.7 7.3 10.0 11.8 12.512 0. 0 2.8 5.3 8.1 11.2 13.811 0.0 4. 4 6.3 8.5 12.0 15.8

Table 2. Self weighted scores for dental stages. 7 teeth (mand ibu lar left side).

BoysStages

To ot h 0 A B C D E F G HM2 0.0 3.2 6.2 9.9 14.4 18.4 20.7 21,9 23.3M1 0.0 8.0 12.6 16-9 21.8 27.4PM2 0' 0 3'1 5.6 9-5 13.7 17'4 20'1 21.4 22.5PM1 0.0 5"9 10'7 15.7 20.7 23"8 25' 4 26.8

GirlsStages

To ot h 0 A B C D E F G H

Mz 0.0 3.6 6.1 9.9 15.3 19.2 21-7 23-0 24.2Ml 0.0 5.4 9.8 14.3 20.1 25-9PMz 0.0 3.7 5.8 9.8 14.7 18.1 20.8 22-3 23.3PM~ 0.0 4,6 9,2 15.1 20.2 23.3 25.1 26.6

Table 3. Self weighted scores for dental stages. 4 teeth M2, Ma, PM2, PMI (ma ndi bul ar left side).

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414 A. Demirjian and H. GoldsteinBoys Stages

Tooth 0 A B C D E F G HM2 0.0 3.3 6.1 9.9 15.0 19.7 21.3 22.1 23.5PM2 0-0 3.2 5.6 9.6 14.2 18.8 20.9 21.7 22.8PMt 0.0 7.1 11.6 16-9 22.8 25.8 26-8 27.911 0.0 7-4 11.5 14.6 18.9 25.7

Girls StagesTooth 0 A B C D E F G H

M2 0.0 3.4 6.3 10.2 15.7 20.0 21.5 22.3 23.5PM2 0.0 3.7 6.2 10.3 15.1 19.1 21.0 21.7 22.8PMI 0.0 5.9 10.2 16.2 21-9 24.6 25.6 26.8It 0.0 8.1 12.2 15.6 20.7 27"0Table 4. Self weighted scores for dental stages. 4 teeth M2, PM2, PM~, 11 (mandibular left side).

The perc entile curves in figures 1-6 enable an assessment of the percentile positi onfor the maturity score of an individual. If required, a conversion of a maturity scoreto a "dental age" may be obtained by finding the age at which the 50th percentilevalue equals the maturity score.

Comparing the systemsAltho ugh we have no absolute standard by which to judge the validity of a dentalmaturity system, we can require it to have two general properties. First, the change in

maturity scores with age should be "s mo ot h" in order to reflect the continuous natureof biological development. Secondly, the individual variabili ty in maturity scores ateach age should be large enough to reflect the natural variability in the population.

Systems7 teeth-- 7 teeth-- M2, PM2, PMt, 11Mz, MI, PM2, PM1 M2, PM2, PML, 11 -M2, M1, PMz, PM~

Age Boys Girls Boys Girls Boys Girls2. 5- 3. 5 0.8 0.7 1.9 1.5 1.1 0.93. 5- 4. 5 2.3 1.9 3.2 3.3 0.9 1.44. 5- 5. 5 3.6 2.3 4.8 4.1 1.1 1-75. 5- 6- 5 3.2 1.7 4.4 3.7 1-3 2.16. 5- 7. 5 1-2 - 1- 2 3.1 1.6 2.0 2.77.5- 8.5 -2 -0 -3 .8 1.5 0.2 3.4 4.08.5- 9.5 -5 .0 -6 .0 0~4 -0 .6 5.4 5.39.5-10.5 -5 .7 -5 .9 -0 .4 -1 .2 5.3 4.710.5-11.5 -4 .6 -4 .5 -0 .7 -1 .3 3.8 3.211.5-12.5 -3 -0 -2 -6 -0 .8 -1 .3 2.1 1.212.5-13-5 -2 .0 -1 .6 -0 .8 -1 .1 1-1 0.413.5-14.5 -1 .3 -0 .9 -0 .8 -0 .7 0.4 0.114.5-15.5 -0 .8 -0 .5 -0 .7 -0 .4 0.1 0.015.5-16.5 -0 .3 -0 .2 -0 .4 -0 .2 0.0 0.016.5-17.5 -0 .1 0.0 - 0. 3 0.0 0.0 0.0

Table 5. Mean difference between systems at each age.Smoothed values.

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New system s for dental maturity 4 15

. . . . . . . . . . . . . . . . I . . . . . . i ~ ~

i i i :i ' ' ?l i ............ ..........::i ::::l~:i;::i ::::: ....... i . ... i i i ~: ~::: ~: i), .i 7 i :::~::: ... ... ... ... ....... ~ . . .. . . ~ : 17" . ~ . . . . . . . . . .' : : : : : ' : : : : : " : ; : : : :: :- ', :: : : :: :: ': :: : . . . . : : : : ; : l . . . . . . . . . . . . .

A . . . . : : : . . . . . . : . . . . . . . . . . . . .U 7(} ' :: " :

Y 60 " " "

: / i : , : : i ,= [ ] [ ] [ ] m l m m i nO 504 0 / ! / . :i , ~ , , , ! i : : : : : : r i : i i , i i i : ~;

20 :i:: ~0 1~ : ,~ / i i : : i : : ] : ::= " ! " BO YS ' i : ' ' I

10 i ~ . " ! i i ! : i : ! ] ! i . . . . .1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

A G E ( y e a r s ]

Figure I . Dental maturity percentiles (7 teeth).

: J i ' . . . .ii ~ ~ ~ - ~

8 ( ] . . - t . . . . . . . . . . i

7~ / . I I ': :t: ':: :l il ii :.:~iiii: .:.~:.! i!i t :: :i? . . . . . . . . . . : I . . . . . . . . . . . . . . :

6C . .. .. . .. : . .~ / : r::,~ i:/!i:i:~:~::r:~::i:::~~i:~i~(:::l::ii~i::!i::i....i .:: :.[: : , / / / i . . . . . 1 . . . . . . '

: ! / ' . i ' l l J r . r i ~ . . . . . . . . . . . : i ; : , : : :! i : , : ~ : i~ i : : : i

/ " / ' ~ / / 1 . . . . i , ! , : , ~ " ~ " : : i . . .. . .. . .. . .. . .. . .. . . : "30 : 1 9 , .~ . / L ~ " : i . : : . : . . . . . . i : . : : !. : . : I ! . : : ! ': . . . . : .20 : : / ~o ~/ ~/ : / i ~ : : I i ~ :: :I ! ! : : I i ::i [ .! i: : n , o , ~ i~ i : : ~:" .~i i n I. oe / : /r I I : : L : : I ! . ~ ! ' ~ i : ' ~ : : , : ! : :1o / ~ o , / , , : ' l i l I :. I i I : ! : i ! : : I ~:: :F~ " ' ~ ' ~. ~ ! [ ~ ~ : ~ ~ ! " :~ : l~ : : l ; ! i : "

;," 3/ ~ ~ i I l: i:: r ;.i; : ,0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

A G E [ y e a r s I

Figur e 2. Den tal matu rity percentiles (7 teeth).

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416 A. Demirjian and H. Goldstein

i: il : i i I'r; lll[ iJil ;i]l l'~. [~ iJ, i; ~1;1:1 ~1- ~1 i i i ~11 .i " i ] ] ]. . . . . . . . . . . . . . . I , ~ ...... , . , t . ~ . : . ~ - .~ - ~ - ~ - - ~ - ~ r .+ .~ - h t - . ~ l : . ~ - I : . : -

I l a ~ ' 1 . ' +~ : ~ ' ~ I { | ! : I { | I I : H i l | l l i ll ' l~ r l I : * l f f f ' F ~ l "~ ' ' ' l ' ~ l E - ' l ~ ' ~ l l r ' l ' ~ I / q ' + - - ] - " l - -~ - t " t --

" ! ff~ 'P~ :H' ~r: k!! f '~ ~ ' :: :: .:.: i .. : :: : ' . .:: .::: i: ... ... .. ::!:::: :: ......I l ,: .; ; -.t!-.t-:. :" -" ~::i::: ::::' : ' ::'" :: :: : ' :!:: :: ~:: :::I::: :::I:: :: :::i:::: ::::1::: :::::-.:: :::::

~~ i: :- J: :~ l : :: : : ~ ::;=i :~-" ... . . . . . . . . ." _:E...'_::f:. . : : : : :- :: : : : : : : : :: . . . . . . '-: :

4o :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::I:::::::::::::::: I3o I~:::!,~::1: ::~ :::1:: ~ ,o I1: : ~ : : ~ . . . . . . . . . . . . . : ~ ::t~{~ ~! :: ::: :: :~:: ~i!~l~!:~ ::: : :: :

:::::::::::::::::::::::::::::::::::::::::~: :: ' . . . . . ..... .... .... ... I::~: :~:~ ...... . :, :: ::::. . . . . . . . . . . .:: ~:iIi:~ :::: : :I::: .. .: : ...I~ . . . . . . . . . ~ o ~ l~ : : { t t ] , . I t . . . . . t . . . . . . . . . . . . . . . I~ . . , : t I20 . . . . . . . . . . . . . . . . . . . . . . . . B . . . . . . . . . .::::::::::::::::::::. . . . . . . . ~ : : . ~ ; ~ . . . . . ....... I ............... :l .... .... ... .... .... .... ..... . . . . . . . . . . ::::::: l OYSI: . . . . I .

~o l i : : i : l : : ! : : l : : : : , , " l ~o~: ~ : : : l : : i : : ] i : : i i i i : : l : : ! i i : : l : ! : : I~ : l li : : l : ! : l : ! : : t: : ! :: t : : t : : : J : !l::;,;:i~:: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.:.I::::L:: :]:: :: :: : : I : :: : : : : : : : : : : : : : : : : : : : : : : : : ~:1::: : : : : : :4::: i l : i l : : l i~:: l :I::I I ::::1 i: :1:::I::1 :i: 1 I I

1 2 3 4 5 6 ? 8 9 10 11 12 13 1 4 15 16 17A G E ( y e a r s )

Figure 3. Dental maturity percentiles (4 teeth I) M2, M~, PM2, PM1.

IO0-" . . . . . .. . . . . . . :+! ! i i l. . . . . . . . . . : i ' , : 7111 i i i ! : i

' .. .. .. i ...... iii1

7o,1:i .. I i: I :: i I:: i i: l:: t: J] ~: :]

: :i :i / ' t : : i i ' : "

i l i ] , : / t : ::: :: 1 : :: :l:.i i .il :-~, :t :::: ::1::: I

:f :: li i:i iiil ::!~: i: ifii i ::i :::,i: I:: :,.:{ii::: : .... :

4 0' :: :: :' ' ' :: ! ~ / : ~ ~ : i ~ ::~ ... . . : : ::::::::::::::::::: ;: 9~ 1 : : 1~ ' ::~ ,:~ :: : ,! :~: : , : : , : , . . . . . . . . . . . . . . " . . . . . ~ , j : / r l , .. , : :

20 i:: ' ,.~'::: i , ': ~ /: :;; : :.;,:~ ::1:i:1:. ' , : ; : : ::~ I" ~ o / /, Z , : : i ~ , : : ~: : , : , . . . . i G I R LS i

1o l J / , ~ , i : , IZ' y r : ' ' I1 2 3 4 5 6 ? 8 9 10 11 12 13 14 15 16 1"7

A G E ( y e a r s )

Figure 4. Dental maturity percentiles (4 teeth I) M2, Mx, PM2, PMx.

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New systems for dental maturity 417

100 i . . . . . . . . . . . . . . . . i ; . . . . ! '

90 ::: i : :: : : : i : : : : : :L::: : : :: i :: : . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :::::::::::::::::::::::::::::::::::::::::::+:::::::+,:::::+~::: ~ : : : : , ~ ; ,~ t ' t . ~1 i : t: ::: : ,: : : : l

T 7O : : . . . . . l ; ' l / I /R~. .. LI:.:::.I:............... : : . : . ' / t I ~ : . . . . . . ~ . . . . .0RE

6O

50 : / i l I ]i j / / / f4 0 : 1 1 I / ' /# ~ol / 113 0 : / . / :"~o/ / '20 r f/

10 / o / I0 q f

1 2 3 4 5 6 7 8

B O Y S

I9 10 11 12 13 14 15 16 17

= G E ( y e a r s )

Figu re 5. Den tal ma turit y percentiles (4 teeth I1) M2, PM~, PM ,, It.

: : . . . . . . . i t : /T 70 ;u J : l l-I- +o I I I:::::I::! 1: :: :: ./ ~j ! ;i tY : : : : : :: : : : : : : : : : : : : : : . : t :SCO 50RE 4 0

100 !ii .i! I i t 11 7 t~I! [ ~ : ~ ' ~ _ ~ ' ~. . . . . . . . . :: ! i.

:~ili:: :L:I: i:it:!::i :i: I~i:~f: : : l f i - ~ J t ~ i~Lt: i :1 I~: / ! / . . . . . . .I i t i i r I : i l : : , ":. [! I: : i. I:::! : I :I:!::,:!:I:!!!i::!I:::!:!:: !::::::::::::::::::::::::::::::: li::!:,

/ f t r / I + I:! I [ I : i ' i : ' " ' " ' . . . .t V t ! ! i i :1 ! i ! t :+ : t : , 1 ' , !# ] t l : i i: ' ; i : I i t : ! I ! i i I :

! , " i / , : + li3 0 : :: :: / i j ' : / , ~ . . . . . . . . . . . . . . . . . . . . . :! I . . . . .~ '0~: . . . . : : ~ o J , . // '~ ' i. . . . . . . . . . .i I : ' : i : I ! I : I i : : t : ] : : G IR L.

I ' ~ o l t . . . . . . . . . . . . . . . . . I :lo r3,,I , I :/ / I i

I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17A G E ( y e a r s )

Figu re 6. De nta l matur ity percentiles (4 teeth 11) M2, PM2, PM~, I~.A.H.B. 2E

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418 A . Dernirj ian a nd 1t . GoldsteinWhen comparing two systems, perfect agreement will be indicated by a constant

difference between an indiv idual 's score at each age. We may therefore use thevariabil ity of the withi n-indi vidual difference as a measure of lack of agreement be-tween systems. The average difference between the systems can be used to convert amaturity score on one system into a maturity score on the other. (Table 5 gives themean differences at each age.)

Thus, to convert a maturity score based on M2, Mx, PM2, PMt to one based on7 teeth for a boy aged 6.0 years we add 3.2 score points.

As a first step, the new 7-tooth system has been compared to the previous one.Table 6 shows, at each age, the average difference, the standard deviation of thedifference, the separate standard deviations for each system and the average rate ofchange of maturity with age. The standard deviation of the difference between the

Average of Average rate ofOld-New; S.D. of separate S.D.'s change with ageMean difference* difference* of two systems (Score pts per year)Age Boys Girls Boys Girls Boys Girls Boys Girls

2. 5- 3. 5 4.3 4.2 1.6 1.6 6.0 6.7 9 93. 5- 4. 5 4.0 4.0 1-1 1.2 6.6 8.0 8 84. 5- 5. 5 3.6 3.5 0.9 1.0 7.6 9.0 8 95 .5-6- 5 2.8 2-6 1.1 1.2 8.6 9.8 11 156. 5- 7. 5 1.6 0.9 1.4 1.7 9-0 9.9 16 207. 5- 8. 5 - 1. 0 - 1. 7 1.5 1-3 8.4 7.8 15 108. 5- 9. 5 - 1. 7 -1 . 4 1.0 1.0 6.9 6.1 7 89.5-10.5 - 0. 9 -0 .5 0.8 0-8 5.1 4.8 5 510-5-11.5 0.0 0.4 0.7 0.6 3.4 3.6 4 311.5-12.5 0.8 1.0 0.5 0.5 2.5 2.6 2 212-5-13.5 1.0 1.1 0.4 0.4 1.8 1.7 2 113.5-14.5 1.0 0.8 0.4 0.4 1.3 1.2 1 114.5-15.5 0.8 0.5 0.3 0.4 0.9 0-8 1 115.5-16.5 0.4 0.2 0.3 0.3 0.5 0.5 - - - -16.5-17.5 0.0 0.0 0.2 0.2 0.3 0.3 - - - -

* Smoothed values.Table 6. Comparisons of individual scores of new and old 7-tooth systems.

two systems up to the age of 13 is not more than about three months of the averagechange in matu rit y per year. After this age the relative value of the stan dard deviationincreases, a reflection of the increasing inde ter mina ncy associated with assigning achronol ogical age to almost fully matur e indi viduals. A similar pattern for both sexesexists for the standard deviations of the separate systems which are between threeand six times the standard deviations of the difference. There is a decrease in thestandard deviations of the difference to about age 6 followed by an increase to age 8and thereafter a steady decrease. This is paralleled by the average rate of change ofmaturity with age where the peak "velocity" occurs at about age 7.

The similarity of patterns and the relatively small values of the sta ndar d deviationsof the differences between the systems implies that only a small change is likely tooccur in moving from one to the other.

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N e w s y s t e m s f o r d e n t a l m a t u r i t y 4 1 9T a b l e 7 c o m p a r e s t h e n e w 7 - t o o th s y s te m a n d e a c h 4 - to o t h s y st e m . A s o m e w h a t

d i f fe r e n t p a t t e r n i s a p p a r e n t . T h e s t a n d a r d d e v i a t i o n s o f th e d i f f e re n c e s d o n o t p a r a l l elt h e s t a n d a r d d e v i a t i o n s a n d t h e r a t e s o f c h a n g e f o r th e s e p a r a t e s y s t e m s (t h e 4 - t o o t hs y s t e m s a r e si m i l a r t o t h e 7 - t o o t h s y s t e m ) . F o r t h e c o m p a r i s o n o f th e 7 - t o o t h a n d4 - t o o t h s y s t e m s th e d e c r e a s e is sl o w t o a b o u t a g e 9 , a n d m o r e r a p i d t h e r e a f t e r. T h es t a n d a r d d e v i a t i o n s a re e q u i v a le n t t o u p t o 1 0 m o n t h s a v e r a g e c h a n g e in m a t u r i t yp e r y e a r as f a r a s a g e 1 3. T h e c o m p a r i s o n b e t w e e n t h e 4 - t o o t h s y s t e m s s h o w a r a p i dd e c r e a s e in t h e s t a n d a r d d e v i a t io n u p t o a g e 6 f o l l o w e d b y a s l o w e r d e c r e a s e t o a b o u ta g e 1 1. I t a p p e a r s t h e r e f o r e t h a t t h e t h r e e s y s te m s a r e n o t m e a s u r i n g p r e c i se l y th es a m e u n d e r l y i n g q u a n t i t y a n d t h a t r e la t iv e l y la r g e d if f e re n c e s c a n o c c u r in m o v i n gf r o m a 4 - t o o t h t o a 7 - t o o t h s y s t e m .

7 teeth 7 teeth M2, Ml , PM2, PMIM2, MI, PM2, PMI - M2 , PM2, PMI , 11 - M2 , PM2, PM1, 11

Age Boys Girls Boys Girls Boys Girls2- 5- 3- 5 3.7 4.0 3.6 4.1 3.8 4.03. 5- 4. 5 3.9 4.2 3-7 3.8 3.4 3.64. 5- 5- 5 3.6 3.8 3-6 3-5 3-0 3.25. 5- 6. 5 3.4 3.6 3.3 3.3 2.9 3.16. 5- 7. 5 3.4 3.5 3-3 3.2 2.8 3.07. 5- 8. 5 3.3 3.3 2.9 2-9 3.8 3.08. 5- 9. 5 3-2 2.9 2.7 2.6 2.7 2-99.5-1 0-5 2.9 2.4 2.4 2-2 2.7 2.810.5-11-5 2.4 2.1 2.0 1.6 2.6 2-511.5-12-5 1.7 1.6 1.5 1.1 2.4 1.812-5-13.5 1.3 1.2 1.0 0.8 1.7 1.313.5-14.5 0.9 0.9 0.7 0.6 1.1 0.814-5-15.5 0.6 0.6 0.5 0.5 0.4 0.415.5-16-5 0.4 0.4 0-4 0.4 0.1 0.116.5-17.5 0.2 0.2 0.2 0.2 0.0 0.0

Table 7. Stand ard deviations of differences between individual scores on new 7-tooth system andthe 4-tooth systems.Smoothe d values.

4 . D i s c u s s i o nT h e d e n t a l m a t u r i t y s y s t em p r e s e n t e d e a r li e r b y D e m i r j i a n et al . ( 1 9 7 3 ) h a s b e e n

u p d a t e d . T h e s a m p l e s iz e h as b e e n i n c r e a se d , e s p e c i a ll y a t t he o l d e r a n d y o u n g e r a g e s,a n d t h e n e w s y s t e m , b a s e d o n t h e s a m e s e v e n t e e t h , u t il iz e s tw o a d d i t i o n a l s t a g e s a n dc o v e r s t h e a g e r a n g e 2 - 5 y e a r s t o 1 7 - 0 y e a r s. T h e 3 r d a n d 9 7 t h p e r c en t il e s h a v e a l s ob e e n e s t i m a t e d a n d p r e s e n t e d i n m a t u r i t y s t a n d a r d s . T h e d i f f e r e n c e s b e t w e e n s c o r e sd e r i v e d f r o m t h e o r i g in a l a n d u p d a t e d s y s t e m s a r e s m a l l . W h e r e s o m e i n d i v i d u a l sh a v e b e e n s c o r e d o n t h e o l d s y s t e m a n d t h e o r ig i n a l r a t i n g s a r e a v a i la b l e , th e y m a yr e a d i l y b e a s s i g n e d t h e n e w s c o r e s . A l t e r n a t i v e l y i t w o u l d b e p o s s i b l e t o u s e t h ea v e r a g e d i f fe r e n ce s g iv e n i n th e f i rs t tw o c o l u m n s o f T a b l e 6 to p r o v i d e a n a p p r o x i -m a t e c o n v e r s i o n .

I t w a s p o i n t e d o u t i n t h e e a r l i e r p a p e r t h a t w h e r e a s i n g l e t o o t h w a s m i s s i n g o rc o u l d n o t b e r a t e d f o r a n y o t h e r r e a s o n i t w a s i m p o s s i b l e t o o b t a i n a v a li d e s ti m a t e o ft h e 7 - t o o t h m a t u r i t y u s i n g j u s t t h e s c o r e s o n t h e r e m a i n i n g s ix t e e t h ( u n l e ss t h e c o r r e s -p o n d i n g t o o t h f r o m t h e r ig h t si d e o f t h e m a n d i b l e w a s a v a i l a b l e f o r s u b s t i t u t io n ) .T h e b e s t t h a t c o u l d b e d o n e i s t o e s t i m a t e s e v e n s e p a r a t e s c o r i n g s y s t e m s , o n e f o r

2E2

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4 2 0 A . D e m i r j i a n a n d H . G o l d s t ei ne a c h c o m b i n a t i o n o f six r e m a i n i n g t e e t h . T h i s is st il l n o t c o m p l e t e l y s a t is f a c t o r yh o w e v e r , s i n c e i t a p p e a r s t h a t e a c h s i x - t o o t h s y s t e m i s m e a s u r i n g a s l i g h t l y d i f f e r e n ta s p e c t o f m a t u r i t y . T h i s r a i se s th e. w h o l e q u e s t i o n o f w h i c h s e t o f t e e th s h o u l d b eu s e d t o d e f i n e d e n t a l m a t u r i t y . D u r i n g t h e d e v e l o p m e n t a l p e r i o d w h e n t h e a s s e s s m e n to f t h e m a x i l l a r y t e e t h w a s t e c h n i c a l l y v e r y d i ff i cu l t u s i n g X - r a y s , w e c o n f i n e d o u rs t u d y t o t h e e v a l u a t i o n o f t h e m a n d i b u l a r o n e s . I n t h e o r i g in a l s y s t em , a ll m a n d i b u l a rt e e t h w e r e s t u d ie d a n d a f t e r ta k i n g a c c o u n t o f th e s y m m e t r y o f t h e m a n d i b le , t h es e v e n t e e t h o f t h e l e ft si d e w e r e c h o s e n a s t h e b a s i s f o r e s t i m a t i n g o v e r a l l d e n t a lm a t u r i t y .

W i t h in t h e o v e r a ll d e v e l o p m e n t o f th e d e n t i t io n h o w e v e r , t h e re m a y b e c e rt a ing r o u p s o f te e t h w h i c h h a v e a d i s ti n c ti v e d e v e l o p m e n t a l p a t t e r n o f th e i r o w n , c o n t r i b u t -i n g a s u b - s y s t e m o f d e n t a l m a t u r i t y . A t p r e s e n t w e h a v e i n s u ff i ci e n t k n o w l e d g e t o s a yw h i c h s u b - s y s t e m s a r e t h e i m p o r t a n t o n e s r e q u i r i n g t h e i r o w n s c o r i n g s y s t e m . W h a tw e h a v e d o n e , t h e r e f o r e , is t o c h o o s e t w o s u b - s y s t e m s w h i c h f o r m c o n v e n i e n t g r o u p so f t e e th f o r r a t i n g p u r p o s e s . T h e r e su l ts o f c o m p a r i n g e a c h s y s t e m w i t h t h e 7 - t o o t hs y s t e m a n d w i t h e a c h o t h e r r a i s e s th e p o s s i b i l it y t h a t s o m e w h a t d i f f e r e n t a s p e c ts o fm a t u r i t y a r e b e in g m e a s u r e d . I n o r d e r t o s t u d y t h e q u e s t io n o f w h e t h e r th e y a r em e a s u r i n g d i f f e r e n t a s p e c ts , w e s h o u l d n e e d t o c o m p a r e c h i l d r e n w i t h l o n g i t u d i n a lr e c o r d s u s i n g t h e d i f f e re n t sy s t e m s . W h e r e o n e o f t h e 4 - t o o t h s y s t e m s is u s ed , e i t h e rb e c a u s e a f u l l p a n o r a m i c r a d i o g r a p h i s U n a v a i l a b l e o r b e c a u s e a t o o t h i s m i s s i n g ,t h i s f a c t s h o u l d b e r e c o r d e d i n r e p o r t i n g a m a t u r i t y s c o r e .

W h e n u s i n g t h e s c o r i n g s y s t e m a n d s t a n d a r d s p r e s e n t e d i n t h i s p a p e r , i t s h o u l db e r e m e m b e r e d t h a t t h e s a m p l e is en t i re l y o f F r e n c h - C a n a d i a n o r ig i n . W e d o n o t a sy e t k n o w h o w f a r t h e r e s u l t s w i l l g e n e r a l i z e t o o t h e r p o p u l a t i o n s . W e w o u l d c o n -j e c t u r e , h o w e v e r , t h a t t h e s c o r e s f o r t h e s t a g e s w i l l n o t v a r y t o o m u c h b e t w e e np o p u l a t i o n s , b u t t h a t t h e m a t u r i t y s t a n d a r d s m a y c h a n g e a p p r e c i a b l y . I t w o u l d b ep o s s i b le t o s t u d y d i f f e r e n c es i n a v e r a g e m a t u r i t y f o r d i f f e r e n t p o p u l a t i o n s u s in g t h ep r e s e n t s c o r in g s y s t e m w i t h r e l a t i v e l y s m a l l s a m p l e s .

W e p l a n t o e x t e n d o u r r e s u l t s i n t w o d i r e c t i o n s . F i r s t w e a r e a c c u m u l a t i n g al o n g i t u d i n a l s e ri e s o f r a d i o g r a p h s t a k e n o n e y e a r a p a r t o n t h e s a m e c h i l d r e n i n o r d e rt o d e r i v e l o n g i t u d i n a l s t a n d a r d s . S e c o n d l y w e a r e s t u d y i n g t h e r e l a t i o n s h i p o f d e n t a lm a t u r i t y t o m e a s u r e s o f s k e l et a l m a t u r it y .

AcknowledgmentsW e a r e v e r y g r a te f u l t o D r . L . P a r a s c h iv e s c u a n d M r . C . L a m a r c h e f o r r a t in g t h er a d i o g r a p h s ; t o D r . G . A l b e r t , c h i e f o f th e d e n t a l c li n ic a t S t e - J u s t i n e H o s p i t a l , f o rp r o v i d i n g u s th e r a d i o g r a p h s o f t h e y o u n g e r a g e g r o u p .

T h i s s t u d y is s u p p o r t e d b y g r a n t s f r o m t h e N a t i o n a l H e a l t h a n d W e l f a r e, C a n a d aa n d t h e D e p a r t m e n t o f H e a l t h a n d S o c ia l S e c u r it y t o t h e N a t i o n a l C h i l d r e n 's B u r e a u ,U . K .

ReferencesDem irjian, A., Goldstein, H ., and Tanner, J. M. (1973). A new sy stem of dental age assessment.Human Biology, 42, 211-227.Healy, M . J. R., a nd Goldstein, H . (1976). An approach to the scaling of categorised attributes.Biometr ika , 63, 219-229.Tanner, J. M., Whitehouse, R. M., Marshall, W. A., Healy, M. J. R., and Goldstein, H. (1975).Assessment o f Skele ta l M atur i ty and Predic tion o f Adul t Height: T W 2 Method. London:Academic Press.

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N e w s y s t e m s f o r d e n ta l m a t u r i ty 421Address correspondence to: Professor A. Demirjian, Centre de Recherche sur la CroissanceHumaine, Universit6 de Montr6aL Montr6al, Quebec, Canada.

Zusammenfassung. Es wird ein aktualisiertes System zur Sch/itzung der Zahnreife vorgestellt. Eserweitert das ursprtingliche System (Demirjian u. a., 1973), basierend auf R/Sntgenaufnahmen yonsieben Z/ihnen, durch EinschluB zweier weiterer Stufen und durch Vergr/51~erung der zugrundelie-genden Stichprobe auf 2407 Kna ben und 2349 M/idchen. Fiir beide Geschlechter werden Perzentil-normen for 2,5 bis 17,0 Jahre gegeben. Weiterhin werden Punktsysteme und Perzentilnormen forzwei unterschiedliche S~,tze yon vier Z/ihnen vorgestellt und alle drei Systeme verglichen. Es wirdgeschlossen, dab sie wohl etwas unterschiedliche Aspekte der Zahnreife messen.R6sum6. Un syst6me mis h jour POUr estimer la maturi t6 dentaire est pr6sent6. I1 6tend le syst6mepr6c6dent (Demirj ian et al . , 1973) bas6 sur des radiograp hies de 7 dents pa r l'inclusion de deux stadessuppl6mentaires, et par l'61argissement de l'6chantillon normatif ~ 2407 garqons et 2349 filles. Lespercent iles pour les 5.ges de 2,5/t 17,0 ans son t pr6sent6s s6par6ment pour les gar~;ons et les filles.Les syst~mes de cotatio n et les percentiles stan dard sont pr6sent6s pour deux ensembles diff6rentsde 4 dents, et une compara ison des trois syst6mes est faite. II est sugg6r6 que ces syst6mes pourrai entmesurer des aspects quelque peu diff6rents de la maturit6 dentaire.