Dietary Chemicals in Relation to Dental Caries - American Chemical

1

Dietary

Chemicals

in

Relation

to

Dental Caries

ROBERT S. HARRIS

Downloaded by 80.82.78.170 on December 19, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch001

Massachusetts Institute of Technology, Cambridge, Mass.

The incidence of dental caries and gingival and peridontal diseases is constantly increasing in the United States, although it varies with geographical location. Caries will not develop if the teeth are caries-resistant, if the mouth is kept clear of nutrients which support caries-producing bacteria, or if no caries-producing bacteria are present. Since permanent teeth begin to develop before two months of age, early nutrition may affect the eventual development of sound teeth. Various elements and compounds in food are classified as cariogenic or cariostatic. While caries in experimental animals is similar to that in man, caution is needed in projecting results of such studies.

This symposium on "Dietary Chemicals in Relation to Dental Caries" was scheduled for presentation before the American Chemical Society because (a) the dental caries problem in the United States is serious, (b) many chemicals natural to foods have caries-producing or cariespreventing properties, (c) the caries activity of foods may be modified by processing or supplementation, (d) most of the literature relating to this subject has been published in journals which chemists (including food chemists) seldom peruse, and (e) it is important that chemists be informed of the potential importance of food chemicals in the control of dental decay. More diseases afflict the mouth than any other part of the human body. Almost everyone in the United States is troubled with gingival and peridontal diseases and with dental caries at some time during his life span. In 1962, more than $2 billion was spent for dental services in the United States (9), a sum equivalent to about 1.5% of the national income and to about 15% of the total amount spent for health services (14). Though some 95,000 dentists are serving the U.S. population, less 1 Harris; Dietary Chemicals vs. Dental Caries Advances in Chemistry; American Chemical Society: Washington, DC, 1970.

2

DIETARY

C H E M I C A L S

VS.

D E N T A L

t h a n 5 0 % o f t h e p e o p l e h a v e ever r e c e i v e d d e n t a l care (14).

CARIES

A t least

t w i c e as m a n y dentists w o u l d b e n e e d e d m e r e l y t o correct c u r r e n t d e n t a l defects i n t h e p e o p l e . T h e d e n t a l caries p r o b l e m , w h i c h has b e e n c a l l e d a "disease o f c i v i l i z a t i o n , " seems to b e w o r s e n i n g . F o r instance, B a r t h o l d i et al. (1) n o t e d t h a t t h e n u m b e r o f caries-free subjects a m o n g e n t e r i n g f r e s h m e n at t h e U n i v e r s i t y o f M i n n e s o t a decreased f r o m 1.8 to 1 . 3 % b e t w e e n 1929 a n d 1959, a n d t h e i n c i d e n c e o f carious teeth rose f r o m 34.8 to 4 9 . 3 % .

I t is

l i k e l y that s i m i l a r trends a r e d e v e l o p i n g r e l a t i v e t o disorders o f t h e soft tissues o f t h e m o u t h . K i t e a n d S w a n s o n (6) r e c e n t l y r e p o r t e d t h e results Downloaded by 80.82.78.170 on December 19, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch001

of a s u r v e y o f the m o d e r n d e n t a l care p r o v i d e d t o f r e s h m e n at t h e M a s s a chusetts Institute o f T e c h n o l o g y .

O n e i n f o u r a m o n g t h e 913 students

b e t w e e n 16 a n d 2 0 years o l d e x a m i n e d h a d i n c i p i e n t g i n g i v a l disease, a n d t h e average D M F T 9.6.

Detectable

( d e c a y e d , m i s s i n g , a n d filled t e e t h ) rate w a s

tooth decay was being controlled i n only 4 2 % of the

students, a n d f e w o f these h a d r e c e i v e d n e e d e d p e r i o d o n t a l care. O r t h o d o n t i c care w a s r e c e i v e d b y o n l y 1 8 % o f t h e students, a n d this w a s d u r i n g a n average o f 2.9 years. D e p e n d i n g u p o n t h e c r i t e r i a u s e d , m a l o c c l u s i o n o c c u r r e d i n 61 t o 7 1 % o f those students w h o s t i l l h a d a l l p e r m a nent teeth. T h e g e o g r a p h y o f d e n t a l caries i n t h e U n i t e d States ( F i g u r e 1 ) is interesting (2).

I t is highest i n t h e N o r t h e a s t , next h i g h e s t i n t h e N o r t h -

J. M. Dunning. "Dental Clinics of North America," Saunders

Figure 1.

Incidence and distribution

of dental caries

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

1.

Dietary

HARRIS

Chemicals

3

west a n d N o r t h - C e n t r a l area, a n d least i n the S o u t h - C e n t r a l area.

The

h i g h e r i n c i d e n c e of caries i n the areas of h i g h e r r a i n f a l l has l e d some to suggest that the l e a c h i n g of m i n e r a l s f r o m the s o i l m a y b e a c o n t r o l l i n g factor i n caries d e v e l o p m e n t i n this country. W h i l e it is true that r a i n w a t e r w i l l s l o w l y r e m o v e m i n e r a l s f r o m the s o i l a n d c o n s e q u e n t l y r e d u c e the m i n e r a l content of l o c a l w a t e r s u p p l i e s a n d of f o o d plants g r o w n o n these soils, the interesting g e o g r a p h y of caries i n the U n i t e d States cannot b e e x p l a i n e d this s i m p l y . F o o d s a n d n u t r i t i o n h a v e i m p o r t a n t effects u p o n o r a l h e a l t h . o b s e r v a t i o n that d e n t a l caries does not d e v e l o p i n germ-free Downloaded by 80.82.78.170 on December 19, 2016 | http://pubs.acs.org Publication Date: June 1, 1970 | doi: 10.1021/ba-1970-0094.ch001

f e d s t e r i l i z e d diets ( I I ) d e c a y process.

The

animals

indicates that b a c t e r i a are essential to the t o o t h

T h e d e m o n s t r a t i o n that caries does not d e v e l o p i n n o r m a l

a n i m a l s f e d b y gastric i n t u b a t i o n ( 5 )

indicates that residues of f o o d

debris are n e e d e d i n the m o u t h to s u p p l y nutrients for the g r o w t h a n d d e v e l o p m e n t of c a r i e s - p r o d u c i n g bacteria. It is p o i n t e d out i n this s y m p o s i u m that m a n y elements a n d c o m p o u n d s i n foods m a y accelerate or r e d u c e the d e v e l o p m e n t of d e n t a l caries ( 8 ) . flavin,

D i e t a r y deficiencies of v i t a m i n s {e.g., A , B , B i , D , E , r i b o 6

2

n i a c i n ) , m i n e r a l s (e.g., C a , P , F e , M n ) , a n d a m i n o acids

(e.g.,

lysine, t r y p t o p h a n ) interfere w i t h the d e v e l o p m e n t a n d m a i n t e n a n c e

of

h e a l t h y tissues i n the m o u t h . B e c a u s e o r a l tissues are sensitive a n d c o n v e n i e n t f o r o b s e r v a t i o n , n u t r i t i o n a l c l i n i c i a n s r o u t i n e l y e x a m i n e the m o u t h w h e n a p p r a i s i n g the n u t r i t i o n status of h u m a n beings. S o m e m i n e r a l s are c a r i o g e n i c , some are cariostatic, a n d some

are

inert w h e n ingested i n the diet. T h e b r a n layers of cereals c o n t a i n org a n i c c o m p o u n d s that h a v e cariostatic p r o p e r t i e s , yet o n occasion

this

" r o u g h a g e " m a y act as a l o c a l i r r i t a n t to the g i n g i v a . Sucrose is c a r i o genic, glucose is r e l a t i v e l y inert, a n d starch is inert. M a n y other elements a n d c o m p o u n d s m a y b e c i t e d to demonstrate that the presence a n d absence of nutrients a n d nonnutrients i n foods p l a y a major role i n determ i n i n g the h e a l t h of o r a l tissues. N u t r i e n t s a n d other c h e m i c a l s i n foods m a y affect the teeth t h r o u g h three routes: b y r e a c t i n g w i t h the t o o t h surface as the f o o d passes t h r o u g h the m o u t h ( l o c a l a c t i o n ) , b y r e a c t i n g w i t h the t o o t h surface after b e i n g a b s o r b e d f r o m the intestine a n d r e t u r n e d to the m o u t h via the s a l i v a a n d t h e n r e a c t i n g w i t h the t o o t h surface

( s y s t e m i c - l o c a l a c t i o n ) , a n d after

b e i n g a b s o r b e d f r o m the intestine a n d e n t e r i n g the t o o t h i n the c i r c u l a t i n g blood (systemic action). T h e systemic influences of n u t r i t i o n a l factors greatest d u r i n g tooth d e v e l o p m e n t .

u p o n the teeth

are

T h e p e r i o d o n t i u m is c o n t i n u a l l y u n -

d e r the influence of systemic factors f r o m the t i m e of e r u p t i o n o f the first t o o t h u n t i l the d e a t h of the host.

The growth, development, and main-

tenance of o r a l tissues are i n f l u e n c e d b y n u t r i t i o n because c e l l g r o w t h


4 and

DIETARY

C H E M I C A L S

VS.

D E N T A L

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

CARIES

are i n -

v o l v e d . D i s t u r b a n c e s i n p r o t e i n m e t a b o l i s m m a y influence m a t r i x f o r m a t i o n i n the e n a m e l a n d d e n t i n of the d e v e l o p i n g t o o t h , as w e l l as the i n t e r c e l l u l a r m a t r i x of the c e m e n t u m , the fibrous p e r i o d o n t a l m e m b r a n e , a n d the a l v e o l a r bone.

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

fats m a y alter v i t a l reactions i n the cells of these tissues.

and

Deficiencies

of v i t a m i n A m a y affect the f o r m a t i o n of e n a m e l m a t r i x a n d the m a i n t e n a n c e of the e p i t h e l i u m of the p e r i o d o n t a l tissue; v i t a m i n C d e f i c i e n c y m a y affect the f o r m a t i o n of the c o l l a g e n m a t r i x i n d e n t i n , c e m e n t u m , periodontal membrane,

a n d alveolar bone; v i t a m i n D deficiency m a y


affect the c a l c i f i c a t i o n of e n a m e l , d e n t i n , c e m e n t u m , a n d a l v e o l a r b o n e , etc.

D e f i c i e n c i e s a n d excesses of m i n e r a l s m a y affect the c o m p o s i t i o n

of the c a l c i f i e d tissues, or m a y alter c e l l m e t a b o l i s m t h r o u g h their role i n co-enzymes

(3).

T h e s e systemic influences are j o i n e d b y l o c a l effects w h e n the t o o t h erupts into the o r a l c a v i t y . I o n exchange reactions w i t h the surfaces the o r a l tissues b y elements

of

a n d c o m p o u n d s present i n the s a l i v a a n d

p u l p fluids b e c o m e i m p o r t a n t .

D e g r a d a t i o n p r o d u c t s of d i e t a r y c a r b o -

hydrates a n d m i c r o b i a l e n z y m e s o n the surfaces of the t o o t h c a n p r o m o t e caries d e v e l o p m e n t . R e c e n t research has d e m o n s t r a t e d that c e r t a i n types of m u c o p o l y s a c c h a r i d e - p r o d u c i n g m i c r o o r g a n i s m s w h i c h r e q u i r e sucrose for t h e i r m e t a b o l i s m m a y be the major cause of d e n t a l caries i n h u m a n beings. A t least three factors ( F i g u r e 2 ) are i n v o l v e d i n the d e v e l o p m e n t of d e n t a l caries: host a n d teeth, m i c r o f l o r a , a n d substrate i n the m o u t h

(4).

C a r i e s w i l l not d e v e l o p i f the teeth are caries-resistant, i f the m o u t h is k e p t c l e a r e d of nutrients

( e s p e c i a l l y sucrose)

w h i c h w i l l sustain

the

g r o w t h a n d m e t a b o l i s m of c a r i e s - p r o d u c i n g b a c t e r i a , or i f the m o u t h is not infected w i t h caries-producing bacteria.

T h u s , caries c a n b e c o n -

t r o l l e d b y a l t e r i n g o n l y one of these c o n d i t i o n s . T h e age of the t o o t h is i m p o r t a n t .

C a r i e s i n d e c i d u o u s teeth m a y

cause e a r l y tooth loss a n d affect the p o s i t i o n i n g of the p e r m a n e n t w h i c h are d e v e l o p i n g b e l o w .

teeth

D e n t a l caries i n the p e r m a n e n t d e n t i t i o n

is of major i m p o r t a n c e because these teeth are " p e r m a n e n t " a n d i r r e t r i e v a b l e i f lost t h r o u g h neglect.

are

T h o u g h d e c i d u o u s teeth are gen-

e r a l l y lost b y 11 years of age, the p e r m a n e n t teeth b e g i n to d e v e l o p before 2 m o n t h s of age. T h u s , n u t r i t i o n m a y h a v e a n effect u p o n the g r o w t h a n d d e v e l o p m e n t of a s o u n d tooth l o n g before i t has e r u p t e d i n t o the mouth. T h e earliest v i s i b l e s i g n of caries is c h a r a c t e r i z e d b y p o r o u s , c h a l k y w h i t e spots i n the e n a m e l . T h e " s m o o t h s u r f a c e " t y p e of caries shows a w i d e - a n g l e d w e d g e of p e n e t r a t i o n . T h e " p i t - a n d - f i s s u r e " caries d e v e l o p a w e d g e of d e c a y that is sharper a n d i n v e r t e d , w i t h the p o i n t at the surface.



1.

Dietary

HARRIS

Chemicals

5

P. H. Keyes and H. V. Jordan, "Mechanisms of Hard Tissue Destruction," American Association for the Advancement of Science

Figure

2.

Factors

responsible

for caries

activity

I n either case, t h e shape o f the lesion corresponds w i t h t h e d i r e c t i o n o f the e n a m e l rods, i n d i c a t i n g that the p a t h o f p e n e t r a t i o n o f d e c a y f o l l o w s s t r u c t u r a l p a t h w a y s . O n c e the surface o f the e n a m e l has b e e n d e s t r o y e d , the b a c t e r i a l i n v a s i o n proceeds

along a n uneven front following the

enamel r o d pattern. D e n t i n a l caries d e v e l o p s as a d i s o r g a n i z a t i o n o f t h e m a t r i x , a n d i n the d i r e c t i o n o f i n c r e m e n t a l g r o w t h lines, c a u s i n g first a l a t e r a l s p r e a d , a n d later a p r o g r e s s i o n a l o n g the d e n t i n a l t u b u l e s . T h e r a t has b e e n u s e d most w i d e l y i n e x p e r i m e n t a l caries research. T h e deep

fissures

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

extent o f d e n t a l caries d e v e l o p m e n t . W h i l e these carious lesions are v e r y s i m i l a r t o those i n m a n , n o e x p e r i m e n t a l a n i m a l has teeth that c o m p l e t e l y resemble those o f the h u m a n b e i n g . T h u s , t h e results o f caries research c o n d u c t e d w i t h rats, hamsters, a n d even p r i m a t e s cannot b e p r o j e c t e d to the h u m a n b e i n g w i t h o u t reservation. D u r i n g the d e v e l o p m e n t o f caries, m i n e r a l s m a y b e w i t h d r a w n f r o m c o n s i d e r a b l e depths i n t h e t o o t h structure, i n spite o f t h e h i g h d e n s i t y of the e n a m e l (12).

D e m i n e r a l i z i n g agents r e a c h into t h e e n a m e l struc-

ture a l o n g p a t h w a y s r e l a t e d p r i m a r i l y t o t h e striated structure o f t h e enamel. D e n t a l caries has b e e n r e p o r t e d to d e v e l o p i n e x p e r i m e n t a l a n i m a l s w i t h i n f o u r days f o l l o w i n g e r u p t i o n (13). time-sequence

O p d y k e ( J O ) has s t u d i e d t h e

o f lesions p r o d u c e d a r t i f i c i a l l y i n h u m a n tooth

enamel

that is b e i n g e x p o s e d t o a n a c i d i c s a l i v a r y - g l u c o s e - a g a r system in vitro. T h e first r e a c t i o n w a s a release o f free m i n e r a l after f o u r d a y s ' exposure; w i t h i n e i g h t days the lesion h a d a characteristic a c i d r e a c t i o n ( p H 4.2-4.5); after the 10th d a y v a r i o u s a m i n o a c i d fractions w e r e o b s e r v e d , a n d , after 20 days l i p i d substances w e r e f o u n d .


finally,

6

DIETARY CHEMICALS VS. DENTAL CARIES


Since the structure of the tooth is important to the pathogenesis of caries, those factors which influence the structure of teeth during development are especially important. Mellanby (7) has been foremost i n promoting the concept that the high susceptibility to caries i n modern man results from the faulty tooth structure caused by diet abnormalities during tooth development. Finally, it should be emphasized that caries development is catalyzed or retarded by the presence of elements and compounds, both nutrients and nonnutrients, which act systemically or locally. These are the subject of this symposium. Acknowledgment Contribution Number 1429 from the Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge, Mass. Literature Cited (1) Bartholdi, W. L . , Peterson, E . E., Crawford, W . H . , J. Am. Dental Assoc. 1961, 63, 868-871. (2) Dunning, J. M., "The Dental Clinics of North America," pp. 291-303, Saunders, Philadelphia, Pa., 1962. (3) Harris, R. S., Ed., "The Art and Science of Dental Caries Research," Academic, New York, 1968. (4) Keyes, P. H . , Jordan, H . V., "Mechanisms of Hard Tissue Destruction," R. F . Sognnaes, Ed., pp. 261-283, Pub. 75, American Association for the Advancement of Science, Washington, D . C., 1963. (5) Kite, O. W., Shaw, J. H . , Sognnaes, R. F., J. Nutr. 1950, 42, 89-103. (6) Kite, Owen W., Swanson, Leonard T., J. Am. Dental Assoc. 1965, 70, 1143-1152. (7) Mellanby,M.,"The effect of diet on dental structure and disease in man," Medical Research Council, Spec. Rept. Ser. #191, London, 1936. (8) Nizel, A. E., "The Science of Nutrition and Its Application in Clinical Dentistry," A. E . Nizel, Ed., Saunders, Philadelphia, Pa., 1966. (9) Office of Business Economics, "Survey of Current Business," U . S. Dept. of Commerce, Washington, D. C., July 1963. (10) Opdyke, D . L . , J. Dental Res. 1960, 39, 698, Abst. 129. (11) Orland, F . J., Blayney, J. R., Harrison, R. W., Reyniers, J. A., Trexler, P. C., Gordon, H . A., Wagner, M . , Luckey, T. D., J. Dental Res. 1954, 33, 147-174. (12) Sognnaes, R. F., "Chemistry and Prevention of Dental Caries," Charles C. Thomas, Springfield, Ill., 1962. (13) Steinman, R. R., Hewes, C. G., Woods, R. W., J. Dental Res. 1959, 38, 592-605. (14) Volker, J. F., "Dental Clinics of North America," p. 385, Saunders, Philadelphia, Pa., 1962. RECEIVED October 27, 1969.


Dietary Chemicals in Relation to Dental Caries - American Chemical

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