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Biochemical studies of dental caries
BIOCHEMICAL
STUDIES
OF DENTAL
CARIES
MAXWELL KARSHAX, PH.T>., NEW YORK, N. Y.
B
IOCHEMICAL investigations designed to throw light on the etiology of dental caries have dealt largely with analyses of saliva, blood, and teeth, and with determinations of metabolic balances of elements involved in calcification. Many of the salivary studies are concerned with the acid-neutralizing power of saliva of caries-free and active-caries groups, and they are thus based on the hypothesis of Miller, that dental caries results from solution of enamel and dentine by acids formed as a result of the action of bacterial enzymes on carbohydrate present on the teeth. It is known that what is actually removed from enamel and dentine, as a result of t,he action of acids, are salts which contain mainly calcium and phosphorus. It is important to not,e that these salts are less soluble in fluids containing calcium and phosphorus than in fluids which do not contain these elements. Indeed, it is most fortunate that saliva contains small amounts of salts of calcium and phosphorus, for otherwise our teeth would gradually dissolve away. The presence of these protective salts is, therefore, one of the most important functions of saliva. But this protective effect varies at any given hydrogen-ion concentration, with the contents of calcium and phosphorus in saliva. In fact, up to a certain optimal point, the greater the amount present, the greater is the protective action. In view of this effect, many studies have been made of saliva of persons with and without dent,al caries, for the amounts of calcium and phosphorus present. It is, of course, clear that saliva, as a protective fluid, would exert its effect by acting on the surfaces of the teeth. Some believe, however, that additional protective influences reside within the toot,h itself; that is, that variations in the chemical composition of teeth determine whether they will or will not decay. This question has been studied in a number of ways, such as chemical analysis of blood for some constituents, as calcium and phosphorus, which might affect the composition of the teeth, and secondly, by analysis of teeth themselves. Finally, a number of investigations have been carried out to ascertain whether the ability of the body to retain calcium and phosphorus, the two main constituents of teeth, plays a part, in protecting them from decay. The proper selection of subjects is one of the most important considerations in an investigation aimed to determine whether groups of persons with active dental caries can be distinguished by chemical means from
of
469
and
Surgeons of
Oral
and Diagnosis,
School at
470
Maxwell Karshan
enough to admit an explorer, were excluded from this group. In the arrestedcaries group, no unfilled cavities were present; the fillings were small, few, occurred occlusally, and were prepared at least five years before salivary tests were made. The active-caries group included those who had active decay apparently of recent origin, accompanied by definite disintegration of enamel, and softened dentine. The number of cavities per person varied’ from a few to many; in subjects having only a few, proximal surfaces were involved. All subjects in the active-caries group had areas of enamel decalcification, usually at the gingival margin, in addition to cavities as already described. Individuals having large cavities with firm, discolored dentine, were not included. The miscellaneous group included individuals who had cavities or fillings but could not be placed in either the arrested- or active-caries groups. It should be emphasized that the presence of a large number of cavities did not necessarily place a subject in the active-caries group. The age range of the subjects in the salivary studies was between 10 and 41 years, 90 per cent of the cases being between the ages of 15 and 25 years. In our investigations two types of saliva, namely unstimulated and stimulated, each collected one to three hours after breakfast, were used. These differ from each other somewhat in composition. Unstimulated saliva refers to the fluid collected with minimum movement of the jaw, cheeks, and tongue, while stimulated saliva refers to the secretion produced while chewing paraf%n. We shall discuss now some of the chemical differences that have beeen found in the saliva of groups of individuals with and without caries.l The data are given in Tables I and II. To summarize these results, in both stimulated and unstimulated saliva, higher mean values were found in the eariesfree than in the active-caries group, for carbon dioxide capacity (a measure of the ability of saliva to neutralize acid), total calcium, inorganic phosphate, and the per cent of calcium removed from saliva on shaking with a commercial preparation of tricalcium phosphate. A lower mean value in the per cent of TABLE MEAN
TYPE OF CASE
Caries free Arrested caries Active caries Miscellaneous
VALUES
NO. OF CASES
FOR STIMULATED
84 35
iz 55 45
-Odds the
groups
that the caries-free
is not
ca
MG./loo
--
100
18.8 23.3
6.0
18.9 21.2
::i 5.6
to chance
AND
P
CARIES
1 COzIN-
GROUPS
j
PROTEIN
, CA;::TY C.C. PER 100 O.C.
PER CENT REMOVED*
C.C.
-z-_
13.4 13.9 12.1 13.2 3.1
65 68 39 48 -~___-~ 8.1
I
20 21 45 36 7.5
I
30.2 30.5 19.5 23.9 7.2
;;+
/PERCENT
160 n.n.
REMOVED
I 258 285 I 284 309 2.4
zi 56 54 2.4
groups error
of
*
difference between and a,ctive-caries
due
= I,(
AGE
146
Bj-betweenmeaniuesof---caries-free and active-caries dividad by the standard the difference
I OF CARIES-FREE
INORGANIC P I
TOTAL
NO. OF SETS OF ANALYSES ---
SALIVA
I
m516to 1
I
>loll-8?ito 1
to 1
I
I
*“Calcium and phosuhorus removed” refers t0 tne amount or calcium taken out of saliva upon shaking 10 CC. with 5 Gm. of a commercial preparation phosphate. The carbon dioxide combining capacity is a measure of the neutralizing saliva against acid.
60 to 1
to 1
, and
, of
phosphorus
tricalcium
power
of
the
Biochemical
Studies
of Dental
471
Caries
phosphorus removed on shaking with tricalcium phosphate was found in stimulated saliva of the caries-free than in the active-caries group. In all these respects the differences between the mean values are statistically significant. The findings in both stimulated and unstimulated saliva for groups of individuals having arrested caries were, in general, similar to those for the cariesfree group, and different from those of the active-caries group, while in most respects, the miscellaneous group was either intermediate between the cariesfree and active-caries groups or similar to the caries-free group. The differences in the action of tricalcium phosphate on both stimulated and unstimulated saliva of caries-free and active-caries groups-the main difference between the two groups-probably indicate that either all or part of thd calcium and phosphorus in stimulated saliva, and the calcium in unstimulated saliva, exists in the caries-free group in forms which differ from those in t.he active-caries group. It should be noted that in all salivary studies in which different groups are compared, although average values for the groups may differ, the ranges of individual values always overlap to some degree. It is well known that statistical methods such as that used in the present studies are specifically designed to evaluate the significance of variability of individual observations in a group. The overlapping of ranges of values in the caries-free and active-caries groups does not invalidate the significance of the differences between the means, although it may well indicate that the composition of saliva is only one of a number of factors associated with dental caries. The s’alivary findings are probably related to dental caries in so far as they are concerned with the conditions governing the solubility of enamel. This solubility depends largely on the concentration of calcium and phosphate ions in the medium bathing the enamel. The content of these ions in saliva is probably always great enough to prevent solution of enamel within the range of hydrogen-ion concentration that occurs in saliva, provided that the saliva has free access to the enamel surface. This may explain in part the relative absence of caries on the more exposed surfaces of enamel. If we assume TABLE MEAN
TYPE OF CASE
VALUES
NO. OF CASES
SALIVA
FOR UNSTIMULATED NO. OF SETS OF ANALYSES
TOTAL ca
INORGANIC P
II OF CBRIES-FREE
ca
AND
P
AGE MC./100
21-zr 18.6 6.5 Caries free 21.0 6.4 Arrested caries 13 29 15.5 5.7 Active caries 25 48 22.1 6.3 Miscellaneous 20 35 Difference between mean values of ?%-caries-free and active-caries groups divided by the standard error of the difference Odds that the difference between 267rPP the caries-free and active-caries to 1 groups is not due to chance See footnotes to Table I.
C.C.
18.5 18.5 14.6 18.7 3.5
to 1
PER CENT REMOVED
54 50 26 39 5.7
>lOC to 1
GROUPS
co2 PROTEIN COMBINING xiiiCAPACITY PER PERCENT C.C. PER REMOVED 100 C.C. c100c . .
13.4 12.9 9.5 10.5 2.9
63 60 67 69 1.3
4 to 1
CARIES
---
267 to 1
313 330 335 328 ----mT
2 to 1
57 55 59 55
1 to 1
473
Maxwell Karshan
that saliva has at least partial access to the more secluded regions in which caries occurs, it would follow that this protective mechanism is interfered with or broken down in such regions when a lesion develops, and the high hydrogenion concentration that results from local bacterial action is then able to cause solution of enamel. With partial access of saliva, relatively high neutralizing power and calcium and phosphate contents may be necessary to prevent enamel from dissolving. The potency of this protective mechanism in saliva evidently varies in different individuals, being influenced by the level of acid-neutralizing substances (as indicated by the CO, capacity), and by the concentrations of calcium and inorganic phosphate or the forms in which they exist. The findings given indicate that saliva of groups of persons with active caries differs significantly from that of groups of persons free from caries, or with arrested caries, in these characteristics. In other words, the findings indicate that, in general, the saliva of persons free from caries would protect enamel against solution by acids to a greater extent than would the saliva of persons with active decay. Studies of blood have not yielded the differences between caries-free and active-caries groups such as have been found for saliva. We analyzed blood from thirty-eight individuals, about equally divided between those having active caries and those free from caries, and ranging in age from 19 to 25 years.2 The average results are given in Table III. With the exception of inorganic TABLE STUDIES
OF BLOOD
IN RELATION
RANGE
(Gm. per 100 c.c.) PH Carbon dioxide content (volume per cent) Carbon dioxide capacity (volume per cent)
TO DENTAL
CARIES
CARIES-FREE
I
Calcium (mg. per 100 c.c.) Inorganic phosphate p&Per 100 C.C.)
III
ACTIVE AVERAGE
RANGE
CARIES I
AVERAGE
9.2
- 11.8
10.6
9.7
. 12.5
10.8
3.1
- 5.4
4.1
2.7
- 4.7
3.7
5.7
- 7.1
6.5
5.8
- 7.5
6.6
7.37 - 7.48 64.8 - 70.1
7.43 67.3
7.31 - 7.51 61.3 - 73.0
7.44 G7.6
59.2
64.4
56.5
64.0
- 68.7
- 70.0
phosphate, there is a striking similarity in the blood values of the caries-free and active-caries groups. For this constituent, the difference between the means was 2.2 times its standard error, indicating that the odds are 35 to 1 that this difference is not due to chance. Thus, the difference between the means for inorganic phosphate borders on significance. Furthermore, it may be seen from the blood pH, carbon dioxide content, and carbon dioxide capacity values, that dental caries does not appear to be associated with either acidosis or alkalosis. Other blood studies, on children, are in general agreement with these results. Hubbell,3 for example, was unable to find any difference in hydrogen-ion concentration and carbon dioxide capacity in caries-free and active-caries groups of children. A summary of studies of blood calcium and inorganic phosphate in children is given in Table IV.
Kiochentical
SYudi~s of Dental TABLE
MEAN
VALUES
473
Cnries
IV
FOR SERUMS CALCIU~I AND INOKGAKIC PHOSPHATE CARIES-SUSCEPTIBLE CHILDREX
IN
ACTIVE
CARIES-FREE
Jundell and Hubbell3 Boyd, Drain Needles and
Magnussene and Steaxnsj Marbergs
CARIES-FREE
AND
CARIES
CALCIUM &IG./100 C.C.
PHOSPHATE MC./100 C.C.
CALCIUJI 31G./lOO C.C.
PHOSPHATE 3m./lOO C.C.
10 55 10:3 10.4 10.52
5.01 4.9 4.2 4.53
9.92 10.1 10.6 10.90
4.71 5.0 4.4 4.22
Brodsky’ was unable to find a relationship between development or progress of dental caries, during a period of thirteen months, and increase or decrease of the calcium and inorganic phosphatelevels of blood serum. Also, Needles and Marberg found no appreciable differences in total or ultrafiltrable calcium or in inorganic phosphate bet,ween children who developed new cavities and those who did not, during a period of one year. Several investigations have been made in an attempt to ascertain whether differences in chemical composition exist between enamel or dentine of sound teeth and the intact enamel or dcntine of carious teeth. No consistent average differences were found for the contents of calcium, magnesium, phosphorus, and carbonate. However, Armstrong and Brekhm? reported a higher average fluorine content in enamel from sound teeth than from carious teeth-an average of 0.0111 per cent for sound teeth as compared with 0.0068 per cent for carious teeth, or nearly twice as much in the former t,han in the latter. Finally, metabolic balance studies have been carried out t,o determine whether the ability of the body to retain calcium and phosphorus is related to the etiology of dental decay. Our studies of Eskimo children, in collaboration with Drs. Siegel and Waugh,” did not show any associa.tion between the degree of retention of calcium and phosphorus, and the presence or absence of caries. The data suggested further that freedom from caries, found in most Eskimos in the area studied, may exist despite such diverse conditions as diets low in calcium and moderately high in phosphorus, or very high in both calcium and phosphorus; diets potentially acid or potentially basic; or diets causing high positive metabolic balances of both calcium and phosphorus, or large negative metabolic balances of these elements. These data also suggested that there is no basis for the view frequently held that the freedom from caries in a primitive people is due to a nutritional superiorit,y of “rmtural” as compared with ‘ ’ civilized ’ ’ diets. REFERENCES
1. 2. 3. 4. 5. 6. 7. 8. 9.
Karshan. M.: J. Dent. Res. 18: 395. 1939. Karshanj M., Krasnow, F., and Krejci, L.: J. Dent. Res. 11: 573, 1931. Hubbell, R.. B.: Am. J. Physiol. 105: 436, 1933. Jundell; I., and Magnussen,“H.: Acta Paediat. 14: 13, 1932. Boyd, J. D., Drain, C. L., and Stearns, G.: J. Biol. Chem. 103: 327, 1933. Needles, M. S., and Marberg, C. M.: J. Lab. Clin. Med. 18: 1227, 1933. Brodsky, R.: J. A. D. A. 20: 1440, 1933. Armstrong, W. D., and Brekhus, J. P.: J. Dent. Res. 15: 311, 1936. Siegel, E. H., Waugh, L. M., and Karshan, M.: Am. J. Dis. Child. 59: 19, 1940.
STUDIES
OF DENTAL
CARIES
MAXWELL KARSHAX, PH.T>., NEW YORK, N. Y.
B
IOCHEMICAL investigations designed to throw light on the etiology of dental caries have dealt largely with analyses of saliva, blood, and teeth, and with determinations of metabolic balances of elements involved in calcification. Many of the salivary studies are concerned with the acid-neutralizing power of saliva of caries-free and active-caries groups, and they are thus based on the hypothesis of Miller, that dental caries results from solution of enamel and dentine by acids formed as a result of the action of bacterial enzymes on carbohydrate present on the teeth. It is known that what is actually removed from enamel and dentine, as a result of t,he action of acids, are salts which contain mainly calcium and phosphorus. It is important to not,e that these salts are less soluble in fluids containing calcium and phosphorus than in fluids which do not contain these elements. Indeed, it is most fortunate that saliva contains small amounts of salts of calcium and phosphorus, for otherwise our teeth would gradually dissolve away. The presence of these protective salts is, therefore, one of the most important functions of saliva. But this protective effect varies at any given hydrogen-ion concentration, with the contents of calcium and phosphorus in saliva. In fact, up to a certain optimal point, the greater the amount present, the greater is the protective action. In view of this effect, many studies have been made of saliva of persons with and without dent,al caries, for the amounts of calcium and phosphorus present. It is, of course, clear that saliva, as a protective fluid, would exert its effect by acting on the surfaces of the teeth. Some believe, however, that additional protective influences reside within the toot,h itself; that is, that variations in the chemical composition of teeth determine whether they will or will not decay. This question has been studied in a number of ways, such as chemical analysis of blood for some constituents, as calcium and phosphorus, which might affect the composition of the teeth, and secondly, by analysis of teeth themselves. Finally, a number of investigations have been carried out to ascertain whether the ability of the body to retain calcium and phosphorus, the two main constituents of teeth, plays a part, in protecting them from decay. The proper selection of subjects is one of the most important considerations in an investigation aimed to determine whether groups of persons with active dental caries can be distinguished by chemical means from
of
469
and
Surgeons of
Oral
and Diagnosis,
School at
470
Maxwell Karshan
enough to admit an explorer, were excluded from this group. In the arrestedcaries group, no unfilled cavities were present; the fillings were small, few, occurred occlusally, and were prepared at least five years before salivary tests were made. The active-caries group included those who had active decay apparently of recent origin, accompanied by definite disintegration of enamel, and softened dentine. The number of cavities per person varied’ from a few to many; in subjects having only a few, proximal surfaces were involved. All subjects in the active-caries group had areas of enamel decalcification, usually at the gingival margin, in addition to cavities as already described. Individuals having large cavities with firm, discolored dentine, were not included. The miscellaneous group included individuals who had cavities or fillings but could not be placed in either the arrested- or active-caries groups. It should be emphasized that the presence of a large number of cavities did not necessarily place a subject in the active-caries group. The age range of the subjects in the salivary studies was between 10 and 41 years, 90 per cent of the cases being between the ages of 15 and 25 years. In our investigations two types of saliva, namely unstimulated and stimulated, each collected one to three hours after breakfast, were used. These differ from each other somewhat in composition. Unstimulated saliva refers to the fluid collected with minimum movement of the jaw, cheeks, and tongue, while stimulated saliva refers to the secretion produced while chewing paraf%n. We shall discuss now some of the chemical differences that have beeen found in the saliva of groups of individuals with and without caries.l The data are given in Tables I and II. To summarize these results, in both stimulated and unstimulated saliva, higher mean values were found in the eariesfree than in the active-caries group, for carbon dioxide capacity (a measure of the ability of saliva to neutralize acid), total calcium, inorganic phosphate, and the per cent of calcium removed from saliva on shaking with a commercial preparation of tricalcium phosphate. A lower mean value in the per cent of TABLE MEAN
TYPE OF CASE
Caries free Arrested caries Active caries Miscellaneous
VALUES
NO. OF CASES
FOR STIMULATED
84 35
iz 55 45
-Odds the
groups
that the caries-free
is not
ca
MG./loo
--
100
18.8 23.3
6.0
18.9 21.2
::i 5.6
to chance
AND
P
CARIES
1 COzIN-
GROUPS
j
PROTEIN
, CA;::TY C.C. PER 100 O.C.
PER CENT REMOVED*
C.C.
-z-_
13.4 13.9 12.1 13.2 3.1
65 68 39 48 -~___-~ 8.1
I
20 21 45 36 7.5
I
30.2 30.5 19.5 23.9 7.2
;;+
/PERCENT
160 n.n.
REMOVED
I 258 285 I 284 309 2.4
zi 56 54 2.4
groups error
of
*
difference between and a,ctive-caries
due
= I,(
AGE
146
Bj-betweenmeaniuesof---caries-free and active-caries dividad by the standard the difference
I OF CARIES-FREE
INORGANIC P I
TOTAL
NO. OF SETS OF ANALYSES ---
SALIVA
I
m516to 1
I
>loll-8?ito 1
to 1
I
I
*“Calcium and phosuhorus removed” refers t0 tne amount or calcium taken out of saliva upon shaking 10 CC. with 5 Gm. of a commercial preparation phosphate. The carbon dioxide combining capacity is a measure of the neutralizing saliva against acid.
60 to 1
to 1
, and
, of
phosphorus
tricalcium
power
of
the
Biochemical
Studies
of Dental
471
Caries
phosphorus removed on shaking with tricalcium phosphate was found in stimulated saliva of the caries-free than in the active-caries group. In all these respects the differences between the mean values are statistically significant. The findings in both stimulated and unstimulated saliva for groups of individuals having arrested caries were, in general, similar to those for the cariesfree group, and different from those of the active-caries group, while in most respects, the miscellaneous group was either intermediate between the cariesfree and active-caries groups or similar to the caries-free group. The differences in the action of tricalcium phosphate on both stimulated and unstimulated saliva of caries-free and active-caries groups-the main difference between the two groups-probably indicate that either all or part of thd calcium and phosphorus in stimulated saliva, and the calcium in unstimulated saliva, exists in the caries-free group in forms which differ from those in t.he active-caries group. It should be noted that in all salivary studies in which different groups are compared, although average values for the groups may differ, the ranges of individual values always overlap to some degree. It is well known that statistical methods such as that used in the present studies are specifically designed to evaluate the significance of variability of individual observations in a group. The overlapping of ranges of values in the caries-free and active-caries groups does not invalidate the significance of the differences between the means, although it may well indicate that the composition of saliva is only one of a number of factors associated with dental caries. The s’alivary findings are probably related to dental caries in so far as they are concerned with the conditions governing the solubility of enamel. This solubility depends largely on the concentration of calcium and phosphate ions in the medium bathing the enamel. The content of these ions in saliva is probably always great enough to prevent solution of enamel within the range of hydrogen-ion concentration that occurs in saliva, provided that the saliva has free access to the enamel surface. This may explain in part the relative absence of caries on the more exposed surfaces of enamel. If we assume TABLE MEAN
TYPE OF CASE
VALUES
NO. OF CASES
SALIVA
FOR UNSTIMULATED NO. OF SETS OF ANALYSES
TOTAL ca
INORGANIC P
II OF CBRIES-FREE
ca
AND
P
AGE MC./100
21-zr 18.6 6.5 Caries free 21.0 6.4 Arrested caries 13 29 15.5 5.7 Active caries 25 48 22.1 6.3 Miscellaneous 20 35 Difference between mean values of ?%-caries-free and active-caries groups divided by the standard error of the difference Odds that the difference between 267rPP the caries-free and active-caries to 1 groups is not due to chance See footnotes to Table I.
C.C.
18.5 18.5 14.6 18.7 3.5
to 1
PER CENT REMOVED
54 50 26 39 5.7
>lOC to 1
GROUPS
co2 PROTEIN COMBINING xiiiCAPACITY PER PERCENT C.C. PER REMOVED 100 C.C. c100c . .
13.4 12.9 9.5 10.5 2.9
63 60 67 69 1.3
4 to 1
CARIES
---
267 to 1
313 330 335 328 ----mT
2 to 1
57 55 59 55
1 to 1
473
Maxwell Karshan
that saliva has at least partial access to the more secluded regions in which caries occurs, it would follow that this protective mechanism is interfered with or broken down in such regions when a lesion develops, and the high hydrogenion concentration that results from local bacterial action is then able to cause solution of enamel. With partial access of saliva, relatively high neutralizing power and calcium and phosphate contents may be necessary to prevent enamel from dissolving. The potency of this protective mechanism in saliva evidently varies in different individuals, being influenced by the level of acid-neutralizing substances (as indicated by the CO, capacity), and by the concentrations of calcium and inorganic phosphate or the forms in which they exist. The findings given indicate that saliva of groups of persons with active caries differs significantly from that of groups of persons free from caries, or with arrested caries, in these characteristics. In other words, the findings indicate that, in general, the saliva of persons free from caries would protect enamel against solution by acids to a greater extent than would the saliva of persons with active decay. Studies of blood have not yielded the differences between caries-free and active-caries groups such as have been found for saliva. We analyzed blood from thirty-eight individuals, about equally divided between those having active caries and those free from caries, and ranging in age from 19 to 25 years.2 The average results are given in Table III. With the exception of inorganic TABLE STUDIES
OF BLOOD
IN RELATION
RANGE
(Gm. per 100 c.c.) PH Carbon dioxide content (volume per cent) Carbon dioxide capacity (volume per cent)
TO DENTAL
CARIES
CARIES-FREE
I
Calcium (mg. per 100 c.c.) Inorganic phosphate p&Per 100 C.C.)
III
ACTIVE AVERAGE
RANGE
CARIES I
AVERAGE
9.2
- 11.8
10.6
9.7
. 12.5
10.8
3.1
- 5.4
4.1
2.7
- 4.7
3.7
5.7
- 7.1
6.5
5.8
- 7.5
6.6
7.37 - 7.48 64.8 - 70.1
7.43 67.3
7.31 - 7.51 61.3 - 73.0
7.44 G7.6
59.2
64.4
56.5
64.0
- 68.7
- 70.0
phosphate, there is a striking similarity in the blood values of the caries-free and active-caries groups. For this constituent, the difference between the means was 2.2 times its standard error, indicating that the odds are 35 to 1 that this difference is not due to chance. Thus, the difference between the means for inorganic phosphate borders on significance. Furthermore, it may be seen from the blood pH, carbon dioxide content, and carbon dioxide capacity values, that dental caries does not appear to be associated with either acidosis or alkalosis. Other blood studies, on children, are in general agreement with these results. Hubbell,3 for example, was unable to find any difference in hydrogen-ion concentration and carbon dioxide capacity in caries-free and active-caries groups of children. A summary of studies of blood calcium and inorganic phosphate in children is given in Table IV.
Kiochentical
SYudi~s of Dental TABLE
MEAN
VALUES
473
Cnries
IV
FOR SERUMS CALCIU~I AND INOKGAKIC PHOSPHATE CARIES-SUSCEPTIBLE CHILDREX
IN
ACTIVE
CARIES-FREE
Jundell and Hubbell3 Boyd, Drain Needles and
Magnussene and Steaxnsj Marbergs
CARIES-FREE
AND
CARIES
CALCIUM &IG./100 C.C.
PHOSPHATE MC./100 C.C.
CALCIUJI 31G./lOO C.C.
PHOSPHATE 3m./lOO C.C.
10 55 10:3 10.4 10.52
5.01 4.9 4.2 4.53
9.92 10.1 10.6 10.90
4.71 5.0 4.4 4.22
Brodsky’ was unable to find a relationship between development or progress of dental caries, during a period of thirteen months, and increase or decrease of the calcium and inorganic phosphatelevels of blood serum. Also, Needles and Marberg found no appreciable differences in total or ultrafiltrable calcium or in inorganic phosphate bet,ween children who developed new cavities and those who did not, during a period of one year. Several investigations have been made in an attempt to ascertain whether differences in chemical composition exist between enamel or dentine of sound teeth and the intact enamel or dcntine of carious teeth. No consistent average differences were found for the contents of calcium, magnesium, phosphorus, and carbonate. However, Armstrong and Brekhm? reported a higher average fluorine content in enamel from sound teeth than from carious teeth-an average of 0.0111 per cent for sound teeth as compared with 0.0068 per cent for carious teeth, or nearly twice as much in the former t,han in the latter. Finally, metabolic balance studies have been carried out t,o determine whether the ability of the body to retain calcium and phosphorus is related to the etiology of dental decay. Our studies of Eskimo children, in collaboration with Drs. Siegel and Waugh,” did not show any associa.tion between the degree of retention of calcium and phosphorus, and the presence or absence of caries. The data suggested further that freedom from caries, found in most Eskimos in the area studied, may exist despite such diverse conditions as diets low in calcium and moderately high in phosphorus, or very high in both calcium and phosphorus; diets potentially acid or potentially basic; or diets causing high positive metabolic balances of both calcium and phosphorus, or large negative metabolic balances of these elements. These data also suggested that there is no basis for the view frequently held that the freedom from caries in a primitive people is due to a nutritional superiorit,y of “rmtural” as compared with ‘ ’ civilized ’ ’ diets. REFERENCES
1. 2. 3. 4. 5. 6. 7. 8. 9.
Karshan. M.: J. Dent. Res. 18: 395. 1939. Karshanj M., Krasnow, F., and Krejci, L.: J. Dent. Res. 11: 573, 1931. Hubbell, R.. B.: Am. J. Physiol. 105: 436, 1933. Jundell; I., and Magnussen,“H.: Acta Paediat. 14: 13, 1932. Boyd, J. D., Drain, C. L., and Stearns, G.: J. Biol. Chem. 103: 327, 1933. Needles, M. S., and Marberg, C. M.: J. Lab. Clin. Med. 18: 1227, 1933. Brodsky, R.: J. A. D. A. 20: 1440, 1933. Armstrong, W. D., and Brekhus, J. P.: J. Dent. Res. 15: 311, 1936. Siegel, E. H., Waugh, L. M., and Karshan, M.: Am. J. Dis. Child. 59: 19, 1940.