Minerals: Fluorine and Dental Caries - Advances in Chemistry (ACS

7

Minerals: Fluorine and Dental Caries

H A R O L D C. H O D G E and F R A N K A. S M I T H

Downloaded by UNIV OF BATH on July 1, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch007

University of Rochester School of Medicine and Dentistry, Rochester, N.Y. 14620

Sources of fluoride entering the body by food and beverages are described. Total daily dietary fluoride in various countries ranges between 0.2 and 2.7 mg. In the U.S., the range appears to be 0.3-0.8 mg per day. Absorbed fluoride ion is transported in the blood in both exchangeable and bound forms. No soft tissues store fluoride other than in sites of ectopic calcification. Excretion of absorbed fluoride is chiefly by way of the urine, 90-95% of the total excreted fluoride. That fluoride retained in the body is found almost entirely in the bone. Levels of skeletal fluoride are related to the levels of fluoride found in drinking water and to age. Reduction in caries incidence by fluoride in various vehicles is reviewed.

The

ubiquitous nature of fluorine is nowhere better illustrated than by its existence i n detectable traces in virtually every item of the normal diet of man all over the world. Fluoride, thirteenth in abundance among the elements, constitutes about 0.078% of the earth's crust—slightly greater than the chloride content, 0.055%. The principal fluoride minerals are fluorspar (calcium fluoride), cryolite (sodium aluminum fluoride), and a large number of fluoride-substituted minerals—e.g., fluorapatite, fluorocarbonates, fluorophosphates, and the fluorosilicates. One means of disseminating fluorides throughout the world has been volcanic action, i n which huge amounts of H F may be emitted. Nommik (78) cites the estimate that 135,000 tons of H F are discharged annually from the volcanoes in the Katmai area of Alaska alone. Modern processing of rock phosphate, a multimillion ton industry and an important source of fluoride dispersion, has helped to control fluoride emission in certain areas. The superphosphate industry i n Florida, for example, by scrubbing fluorides from the effluents, recovers most of that released i n the acid 93 Harris; Dietary Chemicals vs. Dental Caries Advances in Chemistry; American Chemical Society: Washington, DC, 1970.

94

DIETARY

C H E M I C A L S

process. B r e d e m a n ( 8 ) r e v i e w e d the g e o c h e m i s t r y of rocks i n g e n e r a l are h i g h l y v a r i a b l e i n t h e i r

fluoride

VS.

D E N T A L

fluorine.

CARIES

Fluoride

contents a n d , as

w o u l d b e e x p e c t e d , the fluoride content of soils reflects the n a t u r e of the mineral components.

N o m m i k (78)

f o u n d that s a n d y soils i n S w e d e n

u s u a l l y c o n t a i n e d l o w e r concentrations of fluoride t h a n c l a y soils.

The

w e l l waters i n these areas reflected the s o i l fluoride concentrations a n d , to a lesser degree, so d i d the vegetation. f o u n d i n the same f a r m

fluoride

Several-fold variations were

concentrations of different cereals r a i s e d o n the

(78).


S o m e p l a n t s are c h a r a c t e r i s t i c a l l y r i c h i n fluoride; most c o n t a i n o n l y trace a m o u n t s . It seems reasonable to assume that the i n o r g a n i c

fluoride

i n p l a n t s has b e e n p i c k e d u p b y the roots f r o m fluoride i o n i n soil waters. T h e c a m e l l i a f a m i l y is f a m o u s f o r its a b i l i t y to concentrate

fluoride;

d r i e d tea leaves f r e q u e n t l y c o n t a i n s e v e r a l h u n d r e d parts p e r m i l l i o n F . P l a n t materials h a v e not b e e n as i n t e n s i v e l y n o r as w i d e l y s t u d i e d as h a v e a n i m a l tissues, p e r h a p s (as N o m m i k p o i n t s o u t ) because there is n o k n o w n f u n c t i o n f o r fluoride i n plants, a n d w i t h a f e w n o t a b l e exceptions o n l y trace a m o u n t s o c c u r .

Roots a p p e a r to c o n t a i n m o r e t h a n stalks,

w h i c h i n t u r n c o n t a i n m o r e t h a n seeds. H u s k s h a v e l a r g e r concentrations t h a n d o the i n n e r parts of seeds or tubers; e.g., is most a b u n d a n t i n the seed husks ( 7 8 )

i n flour m i l l i n g ,

fluoride

a n d least i n the i n n e r parts of

the g r a i n . P e e l e d potatoes c o n t a i n o n l y 0.07 to 0.25 p p m F , w h e r e a s the peelings r a n g e f r o m 0.5 to 0.8 p p m ( 8 5 ) .

A l t h o u g h the n a t u r e of

the fluoride i n p l a n t m a t e r i a l has not b e e n e l u c i d a t e d c o m p l e t e l y , most (about 80%

or sometimes m o r e ) of the

fluoride

is l e a c h e d easily i n t o

aqueous extracts a n d therefore p r e s u m a b l y occurs as a s i m p l e i n o r g a n i c fluoride.

A l l p l a n t fluoride is c o n s i d e r e d i n o r g a n i c , w i t h the e x c e p t i o n of

that i n a f e w species of p l a n t s of the Dichapetalum T r a n s v a a l or to W e s t A f r i c a , of the Acacia Palicourea

genus n a t i v e to the

f r o m A u s t r a l i a , a n d of the

f r o m B r a z i l , w h i c h c o n t a i n a n o r g a n i c fluoride, either

acetate or a l o n g e r c h a i n fluoro fatty a c i d (47, c a n cleave the

fluorocarbon

bond

79, 80).

fluoro-

Certain bacteria

(34).

T h e process of l e a c h i n g i n t o s o i l w a t e r u l t i m a t e l y makes

fluoride

a v a i l a b l e i n w e l l waters f o r h u m a n c o n s u m p t i o n ; a m a j o r source i n parts of the U n i t e d States is fluoride c a r r i e d l o n g distances i n d e e p s u b t e r r a n e a n streams ( 7 5 ) .

T h e d i s f i g u r i n g effects of excess fluorides o n the teeth a n d

the instances of skeletal fluorosis h a v e p r o m p t e d m a n y surveys of w a t e r fluoride

concentrations.

T h e b e n e f i c i a l effect o n t o o t h h e a l t h of s m a l l

concentrations of fluoride i n c o m m u n i t y w a t e r s u p p l i e s has r e c e n t l y b e e n another reason f o r n a t u r a l w a t e r fluoride surveys.

M o s t water supplies

h a v e o n l y trace a m o u n t s of fluoride (less t h a n 0.1 p p m ) ; i n w i d e l y dist r i b u t e d areas a r o u n d the surface of the earth, h o w e v e r , some w e l l waters

Harris; Dietary Chemicals vs. Dental Caries Advances in Chemistry; American Chemical Society: Washington, DC, 1970.

7.

H O D G E

Minerals:

A N D S M I T H

95

Fluorine

c o n t a i n f r o m 0.5 p p m to 10 o r r a r e l y 20 or m o r e p p m F .

Deeper wells

o f t e n h a v e h i g h e r fluoride concentrations t h a n s h a l l o w w e l l s . I n t h e U n i t e d States t o d a y a b o u t 10,000,000 persons d r i n k w a t e r s n a t u r a l l y fluoridated at concentrations of 0.7 p p m or m o r e . It is e s t i m a t e d that the w a t e r s u p p l i e s of a p p r o x i m a t e l y 4,000,000 persons c o n t a i n "excessive" levels—i.e., a b o v e the o p t i m a l range of 0.7-1.2 p p m (45, I n a d d i t i o n , n e a r l y 62,000,000 residents w a t e r s u p p l i e s (45,


Human

drink

fluoridated

82).

community

82).

Diet

T h e fluoride c o n s u m e d i n the d i e t is s m a l l a n d r e l a t i v e l y constant i n a m o u n t . I n e i g h t countries i n A s i a , E u r o p e , a n d N o r t h A m e r i c a w h e r e d a i l y d i e t a r y fluoride c o n s u m p t i o n has b e e n estimated, at least 0.2 m g F is c o n s u m e d i n e a c h c o u n t r y , a n d i n o n l y three is the c o n s u m p t i o n f r o m f o o d greater t h a n 1 m g d a i l y ( T a b l e I ) .

I n the areas w h e r e the d i e t analyses

w e r e m a d e , w a t e r fluoride concentrations h a v e b e e n l o w w i t h o u t except i o n . C e r t a i n foods c o o k e d i n fluoridated w a t e r t e n d to increase i n content

fluoride

(68). Table I.

Country Canada England Japan Newfoundland Norway Russia Sweden Switzerland U.S.A.

Daily Dietary Fluoride"

Mg F Ingested in Food and Water

Ppm F in Drinking Water

0.18-0.3 0.3-0.5 0.47-2.66 2.74 0.22-0.31 0.6-1.2 0.9 0.5* 0.2-0.3* 0.34-0.80

0.1 trace 0.01-0.08 trace 0.01-0.07 0.2-0.3

6

d

Reference

c

0.1

° After Cholak (IS); cf Osis et al (81). Including 0.07-0.86 mg from green tea. M g F ingested. Including 1 mg from tea. Exclusive of that in drinking water.

36 65 50

22 15 30 1 26

4, 70 42

6

c

d e

T h e major categories of f o o d s ( T a b l e I I ) c o n t a i n traces or m o r e of F (13, 26, 70). most.

T h u s , recent analyses of meats s h o w o n l y a f e w p p m F at

Sea foods h a v e s p e c i a l interest because sea w a t e r contains

1-1.4

p p m F . F i s h meat w i t h o u t b o n e or s k i n has b e e n r e p o r t e d several times to c o n t a i n a b o u t 1 p p m F . Sardines as c o n s u m e d , h o w e v e r , m a y c o n t a i n


96

DIETARY

Table II.


Food

C H E M I C A L S

VS.

D E N T A L

CARIES

Fluoride Concentration ( P P M ) in Fresh Foods Data to 1959 From Cholak (13)

Meats 0.01-7.7 Fish < 0.10-24 Sardines Shrimp F i s h meal Citrus fruits 0.04-0.36 Noncitrus fruits 0.02-1.32 Cereals a n d < 0.10-20 cereal p r o d u c t s Vegetables a n d 0.10-3.0 tubers

Reference

Recent Data 0.14-2 1.08-40 50* 186 0.07-0.17 0.03-0.84 0.18-2.8 0.02-0.9

15, 50, 60, 88 15, 50, 58, 60, 88 15 15 2, 35 2, 15, 35, 50 15, 35, 50, 58, 60, 83, 88, 91 2, 15, 35, 50, 60, 83, 88, 91

° Shrimp meat, 0.4 ppm; shrimp shell, 18-48 ppm (72, 93). as m u c h as 40 p p m . T h e n e w l y d e v e l o p e d p r o t e i n source, fish m e a l , m a y c o n t a i n 186 p p m ( o n e a n a l y s i s ) ; 100 grams of this fish m e a l w o u l d c o n t r i b u t e n e a r l y 20 m g of F to t h e diet. Japanese s h r i m p w a s r e p o r t e d to c o n t a i n as m u c h as 5 0 p p m ; h o w e v e r , S m i t h a n d G a r d n e r ( 9 3 ) f o u n d 0.2-0.4 p p m i n U n i t e d States s h r i m p flesh a n d 1 8 - 4 8 p p m i n t h e shell. B o n e contains m u c h m o r e fluoride ( v a l u e s o f 2 0 0 - 1 0 0 0 p p m are n o t u n u s u a l ) t h a n meat, so that fish eaten bones a n d a l l — s a r d i n e s , f o r e x a m p l e — c o n t a i n r e l a t i v e l y h i g h concentrations. C i t r u s a n d n o n c i t r u s fruits are l o w i n

fluorides—less

than 1 p p m . In

o l d e r analyses, a n o c c a s i o n a l r e p o r t e d h i g h v a l u e m a y s h o w o n l y a f a i l u r e to take precautions against c o n t a m i n a t i o n b y fluoride insecticides.

Cereals

a n d cereal p r o d u c t s u s u a l l y c o n t a i n o n l y a f e w p p m at most, a n d vegetables a n d tubers p r o b a b l y a b o u t 1 p p m , a l t h o u g h u p t o 3 p p m has b e e n r e p o r t e d . U n l e s s a d i e t contains s u b s t a n t i a l amounts of some o f t h e sea foods o r t e a , d i e t a r y fluorides a l w a y s w i l l b e l o w . F l u o r i d e i n g e s t e d i n fluids i n m a n y parts o f t h e w o r l d c a n b e t r a c e d to t h e fluoride n a t u r a l l y present i n t h e d r i n k i n g w a t e r , o r , p a r t i c u l a r l y i n the U n i t e d States, to fluoride a d d e d i n c o m m u n i t y

fluoridation

projects.

Beverages, w i t h t h e e x c e p t i o n o f t e a , a r e n o t i m p o r t a n t c o n t r i b u t o r s of fluoride

( T a b l e I I I ) . A f e w w i n e s c o n t a i n u p to 6 p p m , b u t m o s t less

than 1 p p m . O n e of t h e b e s t - s t u d i e d sources of fluoride i n t h e h u m a n d i e t is t e a . T e a infusions o n t h e average c o n t a i n a b o u t 1 p p m ( 6 5 ) ; instant t e a , s o m e w h a t less. M o s t of t h e fluoride i n b u l k t e a is extractable. w o r k o f R e i d ( 8 6 ) , a n d o f L a w r e n z a n d M i t c h e l l (62),

T h e early

w h o calculated

that green t e a fluoride w a s o n l y a b o u t 5 % less w e l l a s s i m i l a t e d t h a n w a s s o d i u m fluoride i n t h e d i e t o f rats, has b e e n b o r n e o u t b y m o r e r e c e n t


7.

H O D G E

A N D S M I T H

Minerak:

studies. Z i m m e r m a n (106)

97

Fluorine

s h o w e d that 6 0 - 7 0 % o f t h e fluoride i n t e a

leaves c o u l d b e r e m o v e d b y s t e e p i n g o r b o i l i n g f o r a f e w m i n u t e s , a n d Q u e n t o n (85)

f o u n d t h a t 8 6 - 9 2 % o f t h e tea fluoride w a s extractable.

F r e s h coffee b e a n contains u p t o 1.6 p p m ; t h e d e c o c t i o n m u s t b e d i l u t e i n d e e d . I f 2 grams o f instant coffee (1.7 p p m ) are u s e d p e r c u p , t h e F c o n c e n t r a t i o n w i l l b e o n l y 0.02 p p m i n this beverage.

M i l k u s u a l l y has

a b o u t 0.1 p p m , a l t h o u g h a f e w h i g h e r values h a v e b e e n r e c o r d e d . T h e a v a i l a b l e analyses f o r C o c a C o l a a n d f o r orange j u i c e are q u i t e l o w ; i f a

fluoridated

w a t e r s u p p l y is u s e d t o p r e p a r e these d r i n k s , t h e r e s u l t i n g

F concentrations, o f course, w o u l d reflect that o f t h e w a t e r s u p p l y . Downloaded by UNIV OF BATH on July 1, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch007

Since water-borne

fluorides

exceed 1 p p m i n c e r t a i n l o c a l i t i e s , i n

these n e i g h b o r h o o d s w a t e r fluoride w o u l d b e t h e p r i n c i p a l source o f F ingestion. H o w i m p o r t a n t w a t e r c a n b e as a source is s h o w n f r o m L a r g e n t ' s (61) c a r e f u l b a l a n c e studies o f a d u l t s , a g e d 30 t o 57 years, w h o h a d l o n g r e s i d e d i n t h e i r c o m m u n i t i e s , a n d w h o s e fluoride i n t a k e a n d o u t p u t w e r e Table III.

Fluoride i n Beverages Reference

PpmF

Beverage

13 13 50, 106 106 13 100 13 13 39

0.0-6.3 0.15-0.86 0.1-2.0 0.2 0.2-1.6 1.7 0.04-0.55 0.07 0.0-0.05

Wine Beer T e a infusion I n s t a n t (soln.) Coffee b e a n I n s t a n t (powder) Milk Coca Cola O r a n g e juice

Table I V . Relation of Fluoride Ingested to that in Water and Food Consumed 0

Ppm F in Water 1000 21,000

Initial Age, Yrs,

Reduction in Dental Caries, %

9 6-9 6-7 6-7 4-6 6-7 6

70 33 20-22 22-26 23 36 29-36 19

3 3,4 4 6 4 6? 6

1892 983 296

Reference 59 56 105 64 90 94 68

40

Fluoride Lozenges. B i b b y et al. ( 7 ) i n 1955 r e p o r t e d caries r e d u c t i o n w h e n fluoride lozenges w e r e s u c k e d , p e r m i t t i n g t h e p o s s i b i l i t y of some t o p i c a l a c t i o n of fluoride l i b e r a t e d i n t o the s a l i v a . It is not k n o w n w h e t h e r i n some studies of

fluoride

tablets the s c h o o l c h i l d r e n let the

tablets

disintegrate i n t h e m o u t h . Fluoridated Table Salt. F l u o r i d a t e d a n d i o d i z e d salt has b e e n f o r sale i n S w i t z e r l a n d i n most of the cantons f o r a n u m b e r of years. W o r l d H e a l t h Organization recently initiated a

fluoridated

The

salt s t u d y

i n C o l u m b i a , S o u t h A m e r i c a . Suggested a m o u n t s of fluoride that s h o u l d b e a d d e d either to table salt as p a c k a g e d a n d s o l d o r to t h e salt u s e d b y bakers h a v e r a n g e d f r o m 200 to 370 m g N a F / k g salt.

A t present i n

S w i t z e r l a n d , k i t c h e n salt contains 200 m g N a F / k g (90 m g F / k g ) . A recent r e p o r t f r o m t h e W a d e n s w i l area (66)

shows a caries r e d u c -

t i o n i n t h e c h i l d r e n a g e d 7 - 1 2 w h o s e f a m i l i e s u s e d the

fluoridated

salt

f o r 5 years w h i c h is s i m i l a r to b u t a b o u t h a l f that o b s e r v e d i n the c h i l d r e n of t h e s a m e ages i n G r a n d R a p i d s f o l l o w i n g t h e first 5 years of w a t e r fluoridation

there.

S i m i l a r results are r e p o r t e d f r o m Z u r i c h

Fluoridated M i l k .

T h e c a r i e s - p r e v e n t i v e effect of

(67).

fluoride

given i n

m i l k has b e e n r e p o r t e d i n the U n i t e d States b y Rusoff et al. (87)

i n 1962

a n d i n S w i t z e r l a n d b y W i r z (104)

i n 1964.

I n RusofFs s t u d y , 80 s c h o o l

c h i l d r e n i n t h e age r a n g e of 6 - 1 0 years i n i t i a l l y , f o r 4.5 years d r a n k h a l f a p i n t of m i l k d a i l y c o n t a i n i n g 1 m g F . given milk without

fluoride.

C o n t r o l school children were

RusofFs findings w e r e f a v o r a b l e ( a n

80%

l o w e r i n c i d e n c e of d e n t a l c a r i e s ) ; h o w e v e r , t h e g r o u p s are too s m a l l to give reliable quantitative evidence. a p p r o x i m a t e l y as effective as

Wirz found

fluoridated

fluoridated

m i l k to b e

w a t e r i n r e d u c i n g d e n t a l caries.

E r i c s s o n has s h o w n that the fluoride i n m i l k is a v a i l a b l e b o t h f o r a d s o r p t i o n onto t o o t h surfaces a n d f o r a b s o r p t i o n s y s t e m i c a l l y

(23).


110

DIETARY

Fluoride in Bread.

C H E M I C A L S

VS.

D E N T A L

CARIES

E r i c s s o n (24) reports t h a t salt u s e d i n b a k i n g

b r e a d is b e i n g fluoridated f o r a test i n H o l l a n d g r o w i n g o u t o f a n i n v e s t i g a t i o n w h i c h i n d i c a t e d that b r e a d is a less v a r i a b l e i t e m o f d i e t t h a n w a t e r . E g e (21), i n D e n m a r k , proposes t o fluoridate cereals, f o r e x a m p l e , at a l e v e l o f 3.5 m g F t o e a c h k i l o g r a m . T h i s , h e believes, w o u l d also m a k e a less v a r i a b l e source o f fluoride t h a n does w a t e r . Fluoride Dentifrices. T h e effectiveness o f fluorides a p p l i e d i n d e n t i frices has b e e n r e p e a t e d l y d e m o n s t r a t e d (46, p . 4 9 6 ) . T h e extent o f t h e benefit is s t i l l u n d e r d i s c u s s i o n .


Fluoride Mouth Rinses. S o m e e v i d e n c e (e.g., 29, 101) o f a cariesr e d u c i n g effect h a s b e e n presented. T h e usefulness a n d safety o f w a t e r

fluoridation

is buttressed b y i n -

formation o n the tooth health a n d general health of the literally millions of p e o p l e w h o h a v e d r u n k n a t u r a l l y fluoridated w a t e r f o r t h e i r lifetimes, b y 10-year o r l o n g e r studies o f a d e q u a t e l y large groups o f c h i l d r e n i n w h i c h fluoride w a s a d d e d to t h e d r i n k i n g w a t e r s u p p l y , a n d b y a great deal of animal investigation.

E x t e n s i v e , c o n t r o l l e d long-range

studies

of e a c h o f these n e w e r vehicles is n e e d e d before a n y one of t h e m c a n b e r e c o m m e n d e d w i t h t h e same degree o f confidence that w a t e r

fluoridation

can now be recommended. Mechanism. T h e m e c h a n i s m b y w h i c h fluoride i m p r o v e s t o o t h h e a l t h s t i l l r e m a i n s a m y s t e r y , b u t some o f t h e p r o b a b l e factors h a v e

been

i d e n t i f i e d . A p a r t o f t h e p r o t e c t i v e a c t i o n c a n b e a s c r i b e d t o effects o n the teeth, s t r e n g t h e n i n g t h e defense against d e c a y , a n d a p a r t t o effects o n o r a l m i c r o o r g a n i s m s , d u l l i n g t h e edge o f t h e i r d i s i n t e g r a t i v e attack. F l u o r i d e tends to alter t o o t h f o r m a n d structure, p h y s i c a l l y a n d c h e m i c a l l y , i n w a y s that oppose d i s s o l u t i o n ; fluoride tends t o r e d u c e b a c t e r i a l growth and especially bacterial acid production. TOWARD A M O R E PERFECT STRUCTURE.

established f a c t that

fluoride,

I t w a s h a r d to a c c e p t t h e n o w

i n f a m o u s 3 0 years a g o f o r its grotesque

d i s f i g u r e m e n t o f teeth w h e n t a k e n i n excess, is responsible at o p t i m a l levels f o r a m o r e perfect structure.

T h e n u m b e r o f w h i t e spots

(minor

i m p e r f e c t i o n s o f t h e e n a m e l surface) a r e f e w e r w h e n t h e d r i n k i n g w a t e r contains 1 p p m F t h a n at l o w e r concentrations (28).

A b o u t 2 0 % of the

residents o f c o m m u n i t i e s w h e r e o n l y m i n u t e traces o f fluoride o c c u r i n the d r i n k i n g w a t e r e x h i b i t w h i t e spots, whereas i n c o m m u n i t i e s w i t h optimal

fluoridation,

t h e i n c i d e n c e is o n l y 7 - 1 5 % . X - r a y d i f f r a c t i o n s t u d -

ies r e v e a l i n c r e a s i n g c r y s t a l l i n i t y of b o n e a n d t o o t h m i n e r a l w i t h increasi n g percentages o f fluoride. Posner, E a n e s , a n d colleagues (20, 84) h a v e p r o p o s e d that t h e s h a r p e n i n g o f d i f f r a c t i o n lines is e v i d e n c e o f f e w e r c r y s t a l l i n e tablets ( h a l f as m a n y i n h i g h - F b o n e s ) , a n d o f larger v o l u m e f r o m g r o w t h i n w i d t h a n d thickness b u t n o t a l o n g t h e c-axis o f t h e hex-


7.

HODGE

Minerals:

A N D S M I T H

agonal prisms.

Teeth

develop w i t h

r o u n d e r cusps a n d s h a l l o w e r C H E M I C A L

Fluorine more

111 resistant

forms—e.g.,

with

fissures.

C h a n g e s i n c h e m i c a l c o m p o s i t i o n o c c u r of sorts

C H A N G E S .

k n o w n to be associated w i t h lessened s u s c e p t i b i l i t y to caries w h e n w a t e r is

fluoridated.

ficial

T h e fluoride content increases e s p e c i a l l y i n the most super-

l a y e r of the e n a m e l ( F i g u r e 4 ) .

R a d i o f l u o r i d e penetrates i n t o areas

of i n c i p i e n t caries a n d m a y c o n f e r resistance to the extension of cavities (74).

A l t h o u g h the b o n e m i n e r a l contains less c a r b o n a t e (76,

less citrate (109)

77)

and

as the fluoride c o n c e n t r a t i o n increases w i t h o u t c h a n g e

i n the c a l c i u m - t o - p h o s p h o r u s r a t i o , the t o o t h e n a m e l c a r b o n a t e is u n Downloaded by UNIV OF BATH on July 1, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch007

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

(31,69).

H i g h c a r b o n a t e concentrations are c o r r e l a t e d w i t h h i g h e r caries rates i n experimental animals.

^

10,000-

5000

^

1000-

500 0

1

PARTS PER

2

3

4

5

MILLION OF FLUORIDE IN WATER

Figure 4. Relation between waterborne fluoride and fluoride in surface enamel. Adapted from (46) S O L U B I L I T Y

F l u o r i d e ^ t r e a t e d e n a m e l dissolves i n a c i d

R E D U C T I O N .

more slowly than untreated. T h e m o r e fluoride e n a m e l samples n a t u r a l l y c o n t a i n , the s l o w e r the s o l u t i o n rates i n a c i d buffers (in vitro, 51; in vivo, 57). b o d y fluids of

fluorapatite

( a n d p r e s u m a b l y of

The solubility in

fluor-hydroxyapatite)

is

almost c e r t a i n l y less t h a n that of h y d r o x y a p a t i t e . F l u o r i d e m a y f a c i l i t a t e n u c l e a t i o n a n d the i n i t i a t i o n of c a l c i f i c a t i o n , t h e r e b y m a k i n g a m o r e h i g h l y c a l c i f i e d tissue. L E S S E N E D

B A C T E R I A L

A C I D

P R O D U C T I O N .

C o n c e n t r a t i o n s of

fluoride

sufficient to r e d u c e the rate of b a c t e r i a l g r o w t h m a y not o r d i n a r i l y o c c u r


112

DIETARY C H E M I C A L S VS. D E N T A L CARIES

in the mouth; however, lower and perhaps achievable decrease acid production i n susceptible bacteria.

concentrations


Even relatively small concentrations of fluoride—e.g., 2-6 ppm— interfere with acid production i n cultures of oral bacteria under certain conditions (53, 55). Local F concentrations may exist near the enamel surface, available to bacteria, and effective i n reducing the rate of bacterial acid production. The plaque on the surface of the teeth contains relatively high concen trations, averaging about 50 and ranging over 150 ppm F (16,38). W h e n bacteria lying in or on the plaque produce metabolic acids which diffuse toward the enamel surface mineral underneath the plaque, fluoride may be liberated, to form unionized H F at the local p H which diffuses back into the bacteria, effectively hindering further acid production. Literature Cited (1) Abramson, E., et al., Sv. Tandl. Tidskr. 1954, 47, 1. (2) Abuladze, A. S., Pailodze, Yu. B., Kutateladze, Ε. Α., Antelava, Α. V . , Glonti, L . V., Gigiena i Sanit. 1959, 24, 71. (3) Armstrong, W . D., Arch. Oral Biol., 1961, Special Suppl., 4, 156. (4) Armstrong, W . D., Knowlton, M . , J. Dental Res. 1942, 21, 326. (5) Arnold, F. Α., Jr., McClure, F. J., White, C. L., Dental Progr. 1960, 1, 8. (6) Backer Dirks, O., "Advances in Fluorine Research and Dental Caries Prevention," Vol. 2, p. 33, J. L. Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1964. (7) Bibby, B. G., Wilkins, E . , Witol, E . , Oral Surg. Oral Med. Oral Pathol. 1955, 8, 213. (8) Bredemann, G., "Biochemie und Physiologie des Fluors und der Industriellen Fluor-Rauchschaden," Akademie-Verlag, Berlin, 1956, 299 pp. (9) Brit. Dental J. 1965, 7, 119. (10) Buttner, G., J. Dental Res. 1963, 42 (Pt. 2), 453. (11) Call, R. Α., Greenwood, D . Α., LeCheminant, W . H . , Shupe, J. L . , Nielsen, Η. M . , Olson, L . E . , Lamborn, R. E., Mangelson, F . L . , Davis, R. V., Public Health Repts. (U. S.) 1965, 80, 529. (12) Carlson, C. H . , Armstrong, W . D., Singer, L., Am. J. Physiol. 1960, 199, 187. (13) Cholak, J., J. Occupational Med. 1959, 1, 501. (14) Council on Research, Can. Dental Assoc., J. Can. Dental Assoc. 1967, 33, 506. (15) Danielsen, M . E . , Gaarder, T., Univ. Bergen Arbok Naturvitenskap. Rekke, 1956, 20, 15 pp. (16) Dawes, C., Jenkins, C. N., Hardwick, J. L . , Leach, S. Α., Brit. Dental J. 1965, 119, 164. (17) Dean, H. T., J. Am. Water Works Assoc. 1943, 35, 1161. (18) Dean, H. T., Public Health Repts. (U. S.) 1938, 53, 1443. (19) Dietz, V. H., Missouri State Dental Assoc. J. 1953, 33, 7. (20) Eanes, E . D., Zipkin, I., Harper, R. Α., Posner, A . S., Arch. Oral Biol. 1965, 10, 161. (21) Ege, R., Tandlaegebladet 1961, 65, 445. (22) Elliott, C. G., Smith, M. D., J. Dental Res. 1960, 39, 93. (23) Ericsson, Y., Acta Odontol. Scand. 1958, 16, 51.



7.

HODGE AND SMITH

Minerals: Fluorine

113

(24) Ericsson, Y., "Effects of Fluorides in Foods," Symposia of the Swedish Nutrition Foundation, III, Gunnar Blix, Ed., Almqvist and Wiksell, Stockholm, 1965. (25) Ericsson, Y., Malmnas, C., Acta Obstet. Gynecol. Scand. 1962, 41, 144. (26) von Fellenberg, T., Mitt. Gebiete Lebensm. Hyg. 1948, 39, 124. (27) Feltman, R., Kosel, G., J. Dental Med. 1961, 16, 190. (28) Forrest, J. R., Brit. Dental J. 1956, 100, 195. (29) Forsman, B., Sverige Tandlakarforb Tidn 1965, 57, 705. (30) Gabovich, R. D., Gigiena i Sanit. 1951, 6, 31. (31) Gedalia, I., Azaz, B., Schmerling, M., J. Dental Res. 1969, 48, 105. (32) Gedalia, I., Brzezinski, A., Bercovici, B., J. Dental Res. 1959, 38, 548. (33) Gedalia, I., Brzezinski, A., Portuguese, N., Bercovici, B., Arch. Oral Biol. 1964, 9, 331. (34) Goldman, P., J. Biol. Chem. 1965, 240, 3434. (35) Grieser, N., Med. Ernahrung 1965, 6, 30. (36) Ham, M . P., Smith, M . D., Can. J. Res. 1950, 28F, 227. (37) Hardwick, J. L., "Dental Caries and Trace Elements," Ciba Foundation Symposium, Caries-Resistant Teeth, G. E . W . Wolstenholme and M. O'Connor, Eds., Little, Brown and Co., Boston, Mass., 1965. (38) Hardwick, J. L . , Leach, S. A . , "Advances in Fluorine Research and Dental Caries Prevention," J. L . Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1963. (39) Hart, S. M . , J. Assoc. Offic. Agr. Chemists 1961, 44, 633. (40) Held, A.-J., "Advances in Fluorine Research and Dental Caries Prevention," Vol. 2, p. 57, J. L . Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1964. (41) Hennon, D . K., Stookey, G. K., Muhler, J. C., J. Dentistry Children 1966, 33, 3. (42) Heyroth, F. F., "Ingestion of Fluoride Derived from the Drinking Water and Its Elimination by Man," Progr. Rept., Public Health Service Grant G 3363, Dec. 1, 1951, to May 31, 1954. (43) Hodge, H . C., "Fluoride Mineral Metabolism," Vol. II, Part A , C. L . Comar and F. Bronner, Eds., Academic Press, New York, 1964, 649 pp. (44) Hodge, H . C., J. Pediat. 1963, 63, 454. (45) Hodge, H. C., Smith, F. A., Ann. Rev. Pharmacol. 1968, 8, 395. (46) Hodge, H . C., Smith, F . A., "Fluorine Chemistry," Vol. IV, J. H . Simons, Ed., Academic Press, New York, 1965, 786 pp. (47) Hodge, H . C., Smith, F. A., Chen, P. S., "Fluorine Chemistry," Vol III, J. H . Simons, Ed., Academic Press, New York, 1963, 240 pp. (48) Hodge, H . C., Smith, F. A . , Gedalia, I., "Fluorides in Human Health," Y. Ericsson, Ed., World Health Organization, Geneva, in press. (49) Horowitz, H. S., Heifetz, S. B., Clin. Pediat. 1966, 5, 103. (50) Iizuka, Y., Nippon Eiseigaku Zasshi 1964, 19, 1. (51) Isaac, S., Brudevold, F., Smith, F. A., Gardner, D . E . , J. Dental Res. 1958, 37, 254. (52) Jackson, D., Weidmann, S. M., J. Pathol. Bacteriol. 1958, 76, 451. (53) Jenkins, G. N., Arch. Oral Biol. 1959, 1, 33. (54) Jenkins, G. N., World Rev. Nutr. Dietet. 1967, 7, 138. (55) Jenkins, G. N., Ferguson, D . B., Edgar, W . M . , Helv. Odontol. Acta 1967, 11, 2. (56) Kessler, W., Solth, K., Stoma 1958, 11, 14. (57) King, W . J., Weiss, S., Volpe, A . R., Eigen, E., Ann. N. Y. Acad. Sci. 1965, 131, 713. (58) Kirchgessner, M . , Weser, U . , Friesecke, H., Oelschlager, W., Z. Tierphysiol. Tierernahr. Futtermittelk. 1963, 18, 193.



114

DIETARY CHEMICALS VS. DENTAL CARIES

(59) Knappwost, Α., Deut. Med. Wochschr. 1956, 81, 92. (60) Kolomiitseva, M . G., Vopr. Pitaniya 1961, 20, 55. (61) Largent, E . J., "Fluorosis. The Health Aspects of Fluorine Compounds," Ohio State University Press, Columbus, Ohio, 1961, 186 pp. (62) Lawrenz, M . , Mitchell, Η. H . , J. Nutr. 1941, 22, 621. (63) Leonhardt, N . , "Advances in Fluorine Research and Dental Caries Pre vention," Vol. 2, p. 49, J. L . Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1964. (64) Leonhardt, N . , Arch. Oral Biol. 1961 (Special Suppl.), 6, 17. (65) Longwell, J., Roy. Soc. Promot. Health J. 1957, 77, 361. (66) Marthaler, T. M . , "Advances in Fluorine Research and Dental Caries Prevention," Vol. 2, p. 45, J. L . Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1964. (67) Marthaler, T. M . , Schweiz. Monatsch. Zahn. 1961, 71, 671. (68) Martin, D. J., J. Dental Res. 1951, 30, 676. (69) McCann, H . G., Brudevold, F., "Environmental Variables in Oral Dis ease," p. 103-118, S. J. Kreshover and F. J. McClure, Eds., Publ. 81, Am. Assoc. Advan. Sci., Washington, D. C., 1966. (70) McClure, F . J., Public Health Rept. (U. S.) 1949, 64, 1061. (71) Minoguchi, G., Bull. Stomatol. Kyoto Univ. 1964, 4, 45. (72) Muhler, J. C., "Fluorides in Human Health," Y. Ericsson, Ed., World Health Organization, Geneva, in press. (73) Muhler, J. C., Univ. of Indiana, Bloomington, Indiana, private commu nication. (74) Myers, H . M., Hamilton, J. G., Becks, H . , J. Dental Res. 1952, 31, 743. (75) Nichols, M. S., "Fluoridation as a Public Health Measure," J. H . Shaw, Ed., Am. Assoc. Advan. Sci., Washington, D . C., 1954, 232 pp. (76) Nikiforuk, G., Grainger, R. M . , "Tooth Enamel, Its Composition, Prop erties and Fundamental Structure," pp. 26-31, Rept. Proc. Intern. Symp., London, 1964, publ. 1965. (77) Nikiforuk, G., McLeod, I. M . , Burgess, R. C., Grainger, R. M . , Brown, H . K., J. Dental Res. 1962, 41, 1477. (78) Nommik, H . , "Fluorine in Swedish Agricultural Products, Soil, and Drinking Water," Esselte Aktiebolag, Stockholm, 1953, 121 pp. (79) Oelrichs, P. B., McEwan, T., Nature 1961, 190, 808. (80) Oliveira, M . M . , Experientia 1963, 19, 586. (81) Osis, D., Spencer, H., Samachson, J., IADR Abstracts 1969, 148. (82) Ostroff, J., Dept. of Health, Education, and Welfare, Public Health Service, Washington, D . C., private communication. (83) Pisareva, M . K., Vestnik Akad. Nauk Kazakh. SSR 1955, 11, 86. (84) Posner, A . S., Eanes, E . D., Zipkin, I., Proc. Second European Symp. Calcified Tissues, pp. 79-88, Liege, Belgium, 1964. (85) Quentin, K.-E., Souci, S. W., Indinger, J., Ζ. Lebensm. Untersuch. Forsch. 1960, 111, 12. (86) Reid, E., Chinese J. Physiol. 1936, 10, 259. (87) Rusoff, L . L . , Konikoff, B. S., Frye, J. B., Jr., Johnston, J. E., Frye, W. W., Am. J. Clin. Nutr. 1962, 11, 94. (88) Ruzhnikova, T. N . , Vopr. Pitaniya 1963, 22, 86. (89) Scassellati Sforzolini, G., Cusma, N . , Mastrantonio, Α., "Advances in Fluorine Research and Dental Caries Prevention," Vol. 2, p. 213, J. L . Hardwick, J.-P. Dustin, and H . R. Held, Eds., Macmillan, New York, 1964. (90) Schutzmannsky, G., Arch. Oral Biol. 1961 (Special Suppl.), 6, 27. (91) Shtifanova, A. K., Zdravookhranenie Kazakhstana (Alma-Ata) 1962, 22, 60. (92) Singer, L., Armstrong, W . D., Arch. Oral Biol. 1969, 14, 1343.



7.

HODGE AND SMITH

Minerals: Fluorine

115

(93) Smith, F . A., Gardner, D . E . , University of Rochester School of Medicine and Dentistry, Rochester, N . Y., private communication. (94) Stawinski, K., Wojciak, L . , Abt, S., Czasopismo Stomatologiczne 1963, 16, 611. (95) Strean, L . P., Beaudet, J. P., N. Y. State J. Med. 1945, 45, 2183. (96) Suttie, J. W., Phillips, P. H., "Fluorine and Dental Health. The Pharmacology and Toxicology of Fluorine," J. C. Muhler and M . K. Hine, Eds., Indiana University Press, Bloomington, Ind., 1959, 216 pp. (97) Tank, G., Storvick, C. A., J. Am. Dental Assoc. 1965, 70, 394. (98) Taves, D . R., Nature 1968, 220, 582. (99) Taves, D . R., private communication, 1969. (100) Teply, L . J., Food Technol. 1958, 12, 485. (101) Torell, P., Ericsson, Y., Acta Odontol. Scand. 1965, 23, 287. (102) Tosteson, D . C., Acta Physiol. Scand. 1959, 46, 19. (103) Weaver, R., Brit. Dental J. 1950, 88, 231. (104) Wirz, R., Schweiz. Monatsch. Zahn. 1964, 74, 767. (105) Wrzodek, G., Zahnartzl. Mitteil. 1959, 47, 258. (106) Zimmerman, P. W., Hitchcock, A . E . , Gwirtsman, J., Contrib. Boyce Thompson Inst. 1957, 19, 49. (107) Zipkin, I., Lee, W . A., Leone, N . C., Am. J. Public Health 1957, 47, 848. (108) Zipkin, I., Likins, R. C., McClure, F . J., Steere, A. C., Public Health Repts. (U. S.) 1956, 71, 767. (109) Zipkin, I., McClure, F . J., Lee, W . A., Arch. Oral Biol. 1960, 2, 190. RECEIVED August 14, 1968. Preparation of this manuscript was supported in part under contract with the U . S. Atomic Energy Commission at the University of Rochester Atomic Energy Project, Rochester, N. Y. and has been assigned report number UR-49-889 and in part by the USPHS Grant GM-15190.


Minerals: Fluorine and Dental Caries - Advances in Chemistry (ACS

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