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Methods of prevention and control of dental caries
Methods of prevention and control of dental caries Robert G. Kesel, D.D.S., 'Chicago
Approximately 90 per cent of the teeth now lost before middle age could be saved in the future adult population of this country by the application of what is already known about the control and prevention of dental diseases. A major problem is to find the means and the will for applying what is known. The public health dentist can play a major role in the solution of that problem. Teeth are lost for two principal reasons: ( 1) destruction of the crowns by caries and ( 2) destruction of the at taching tissues by inflammation and de generation. Although not all the intricate complications in the etiology of caries have been unraveled, sufficient under standing of the basic factors has been gained to place preventive treatment on a rational basis; and the possibility of con trolling the progress of carious destruc tion through good operative dentistry at an early age is well established. The fac tor most often responsible for periodontal destruction is inflammation that can be traced to some local irritation. Early recognition of deviations from normal color, contour and texture of the gingiva, and institution of proper treatment to alleviate these symptoms, could result in tremendous reduction in the loss of teeth.
port the generally accepted theory that bacterial activity is a major factor. The fact that cavities invariably occur where microorganisms can accumulate and re main relatively undisturbed for long periods of time has provided circumstan tial evidence that bacteria are associated with the destructive process. Direct evi dence that bacteria are required for the production of caries is accumulating through the germfree animal studies con ducted at the University of Notre Dame in collaboration with the Zoller Clinic of the University of Chicago.2 Ordinary rats fed a caries-producing diet develop a high incidence of this disease. Germfree animals fed the same diet develop no carious lesions. Further evidence show ing the importance of the local environ ment, including the bacterial flora, has been obtained by stomach tube feeding of rats.3 When a caries-producing diet is placed in the stomach by this method, so that it does not come into contact with the teeth in passing through the mouth, no carious lesions develop. The principal agent that destroys the calcified tissues of the teeth is probably acid in character. Many investigations4 have demonstrated the production of
P R IN C IP A L C A U S A T IV E F A C T O R S
Departm ent o f app lie d materia medica and thera peutics, University o f Illinois C ollege o f Dentistry. 1. Kesel, R. G . Dental caries: etiology, control and a ctivity tests. J.A .D .A . 30:25 Jan. 1943. 2. O rland, F. J .t and others. Use of the germfree animal technic in the study o f experim ental dental canes. I. Basic observations on rats reared free o f all microorganisms. J. D. Res. 33:147 A p ril 1954. 3. Kite, O . W .; Shaw, J. H .t and Sognnaes, R. F. An influence on dental caries incidence produced in rats by tube feeding. (A bst.) J. D. Res. 29:668 O ct. 1950. 4. National Research C ouncil. Survey of the literature of dental caries. Washington, D. C., National Academy of Sciences, 1952.
There are many predisposing conditions that may influence the carious process such as age, heredity, emotions, state of health, salivary flow and composition, tooth structure and position, but the actual destructive forces are few .1 Evi dence continues to accumulate to sup 455
456 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
cavities in the enamel by weak acids. Recent experiments, under artificial con ditions, have produced early lesions in the enamel that are indistinguishable from lesions that develop in the oral cavity.5,6 The agents used to produce these lesions under laboratory conditions are acid. There is no instance in which anything resembling typical carious lesions has been produced artificially with nonacid substances. Several investi gators have shown that when the tooth tissues are subjected to alkaline agents or proteolytic enzymes, no readily demon strable effect appears.7'9 If tooth tissues are exposed to a weak acid so that some décalcification takes place, then enzymes such as trypsin, pepsin or collagenase can exert a destructive action. Apparently, the carious process requires both acidic and enzymic components, and the natural carious process is probably one of intermittent periods of décalcification followed by lytic decomposition. An association between acid produc tion in the oral cavity and carious ac tivity has been shown in numerous studies. Several investigators have found that if a caries-susceptible person rinses his mouth with a. glucose solution, the potentiometer readings made with suit able electrodes to determine acid forma tion indicate that sufficient acid is formed on the tooth surface within a few minutes to be potentially harmful to the calci fied tissues.10-12 Individuals not suscept ible to caries show no such acid produc tion. Recent studies in which an indicator dye, methyl red, was used also showed acid conditions in carious regions.13,14 This dye changes in color from yellow to red as acid is formed. When applied to the surfaces of the teeth after a sugar rinse, red coloration de velops in the areas where the carious de struction appears to be taking place. This method is being studied currently in the hope of developing a simple caries-activity test that can be used in the dental office to demonstrate to the patient con
ditions in his own mouth. The long recog nized association of acidogenic and aciduric bacteria with active caries is further circumstantial evidence of the importance of the acid factor. The only type of food taken into the mouth which can develop an acidity of sufficient strength to dissolve enamel is carbohydrate. The carbohydrates are converted to acid by enzymatic action. The simpler the carbohydrate, the more rapidly is it converted to acid. Thus, the simple sugars— glucose, fructose, sucrose — are more readily converted than are the polysaccharides— the starches. Many dietary studies have shown an association between refined carbohydrate consump tion and caries activity. It is well known that the amount of caries any population experiences is roughly proportional to its sugar consumption. It is important that experimental caries cannot be produced in laboratory animals unless the diet con tains a readily fermentable fraction. CONTROL
OF
C A R IE S
When these observations are collated— that is, the association between bacteria, carbohydrates, the production of acids
5. Weîsberger, D. Role o f glucose in production of a rtific ia l caries. J. D. Res. 29:14 Feb. 1950. 6. Dreîzen, S., and Spies, T. D. D écalcification and discoloration of intact, non-carious human tooth crowns by an oral strain of Lactobacillus acidophilus. Oral Surg., O ral Med. & O ral Path. 4:388 March Î95I. 7. pannenberg, J. L., and Bibby, B. G. E ff e c t if zinc chloride and potassium ferrocyanide on proteolysis. J. D. Res. 29:177 A p ril 1950. 8. Engel, M . B. Softening and solution o f the dentin in caries. J.A .D .A . 40:284 March 1950. 9. Frank, M. R. Etiology o f dental caries. Décalcifica tion by acids: can it be the orig in a l cause of dental caries? L'înform atîon-dent. 33:7, 1951. 10. Stephan, R. M. Intra-oral hydrogen-ion concentra tions associated with dental caries activity. J. D. Res. 23:257 Aug. 1944. 11. Fosdick, L. S.; Campaigne, E. E., and Fancher, O. Rate o f acid form ation in carious areas. The etiology of dental caries. Illinois D. J. 10:85 March 1941. 12. Stralfors, A lla n. Investigations into the bacterial chemistry of dental plaques. Stockholm, Tryckeri A.-B. Thule, 1950. 13. Hardwick, J. L., and Manley, E. B. Caries o f the enamel. II. Acidogenic carles. Brit. D. J. 92:225 May 6, 1952. 14. Arnim , S. S., and Hardwick, J. L. C lin ica l demon strations o f acid production by mouth organisms using aqueous methyl red. North-W est Den. 33:147 May 1954.
K E S E L . . . V O L U M E 52, A P R IL 1956 • 457
from bacterial action on carbohydrate and the requirement of acid for tooth destruction— it is obvious what the prin cipal factors in tooth destruction are and what steps can be taken to prevent or control this disease. A rationale based on the factors outlined for reducing carious activity could include the following: 1. Restriction of the amount of fer mentable carbohydrate in the diet. 2. Production of a tooth tissue more resistant to acid and enzymatic action. 3. Removal of fermentable material from the surfaces of the teeth before it is converted into acid. 4. Employment of nontoxic antibac terial agents to eliminate the micro organisms associated with the decay proc ess or to interfere noticeably with their metabolism. 5. Placement of inhibitors in the mouth that interfere with or destroy the enzymes responsible for the conversion of carbohydrate to acid. 6. Neutralization of acids as rapidly as they are formed on the tooth surfaces. The most effective means of prevent ing the initiation of carious lesions is a dietary program that sharply reduces the amount of sugar consumed. If refined sugar could be removed from the diet, the caries problem would be eliminated. In the United States in the neighborhood of 100 pounds of sugar per person per year is consumed. Twenty-five to 40 pounds of sugar per year would be suf ficient to supply all the calories that are needed from a carbohydrate source for good nutrition.15 The excess 60 to 75 pounds of sugar is detrimental for several reasons. It is producing a state of malnu trition, particularly among children, be cause it is a great appetite appeaser. It, like alcohol, contributes little to nutrition outside of caloric energy. Yet it is a com mon article of diet, particularly between meals, lessening the appetite for more nu tritious material at mealtime. A report by a major candy manufacturer indicated that the annual consumption of candy
for 1950 was 17 pounds per person.16 The candy consumption was compared audaciously with that of butter, cheese and other products of high nutritional value. The article stated that the annual consumption of butter was ten pounds and of cheese seven pounds per person. The combined consumption of butter and cheese barely equaled that of candy. If the leaders of the candy industry of this country are proud of their ac complishment, they should look at Britain’s record. The British cocoa, chocolate and confectionery alliances have reported that, since candy was dera tioned, Britons lead the world, consum ing at the rate of 26 pounds per person annually. Such comparisons indicate the tremendous amount of material being eaten to satisfy appetite without provid ing good nutrition. Sugar consumption is producing obesity in some children and certainly in the adult population, as well as providing ammunition for the carious process in both. It may lead to vitamin B complex deficiency because of the need for this vitamin in the metabolization of useless calories. Much of the excess sugar is being taken in forms such as bottled beverages, chewing gum, pastries and jams that the population does not regard as sugar. Too many think of sugar only as the crystallin form in the sugar bowl. An evaluation of the sugar content of various items that are popularly con sumed has been published in t h e j o u r n a l
OF
T H E
A M E R IC A N
D EN TAL
A S S O C IA
Mimeographed copies of that list are available through some state health departments. They should be given to patients in whom caries control is being attempted. Nearly all will express amaze ment at the sugar content that is not T I O N . 17
15. Massler, Maury, and Zwemer, J. D. Rampant caries. (Its clinical management.) Illinois D. J. 20:407 Sept. 1951. 16. Drug News, Sept. 1950, p. 23. 17. Brauer, J. C. M astication the detergent, the adequate and the low-sugar diets; their effects on dental caries. J.A .D .A . 39:682 Dec. 1949.
458 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
apparent to the consumer; for instance, seven teaspoons of sugar in a candy bar; four to five teaspoons in a bottle of soft drink and 14 teaspoons of sugar in a piece of cherry pie. Although management of caries through dietary channels may be difficult, an attempt certainly should be made to improve nutrition and to reduce caries by moderation in sugar consumption. Diet histories should be taken over a period of at least one week, and specific attention should be drawn to items in the diet that are high in sugar. It is not enough to request the reduction or re moval of such items from the diet. Satis factory substitutes should be emphasized. For in-between-meal snacks, nuts, pop corn, potato chips, cheese and other items that are appetite-appeasing but not readily fermentable, should be recom mended. Sample menus should be pro vided for breakfast, lunch, dinner and in-between-meals ; items to be avoided and those to be eaten should be listed. A sample of such menu recommendations has been provided by the Lederle Labora tories in one of its pamphlets on dental health.18 Copies of it, with some modi fications made by the author, have been found helpful in caries control work (table). It must be recognized that there are strong economic and psychological dis advantages in attempting the control of caries by sugar restriction. Sugars are palatable, readily available, widely ad vertised and economical as a source of caloric energy. Individuals— even den tists— like their sweets, and that is one reason greater professional emphasis is not placed on this effective means of con trol. Some dentists hesitate to recom mend vigorously what they themselves do not practice. This practical disad vantage necessitates consideration of other means for reducing caries activity. Another effective means, with suffi cient evidence to support the claims for it, is the use of fluorides either through
water fluoridation or topical application of fluoride solutions. Any means for caries control that requires conscientious co operation on the part of the individual, that denies him something which he en joys or requires him to perform a ritual that is inconvenient, cannot be too effec tive in controlling caries in large num bers of people. But an agent that will give partial resistance and that can be provided without personal effort on the part of the individual is fluoridation of the drinking water. It should be an effec tive mass means of reducing caries. The disadvantage that may come from such an easy way is, perhaps, the implicit re liance on fluorine in the drinking water to give complete protection against car ies. If water fluoridation develops a false sense of security that encourages in creased sugar consumption and relaxed oral hygiene, perhaps more harm than good may result from water fluoridation, at least for some people. It should be emphasized always that fluorine is not a complete protector; that in communi ties where fluorides are present in op timal amounts in the drinking water, there is still much tooth decay. The same vigilance as to other measures for caries control is required, and periodic exam ination and restoration of the cavities that will develop are essential if water fluoridation is to obtain its maximum result. For many years the toothbrush has been advocated as a weapon against caries. Skepticism has developed about its effectiveness because of the increas ing incidence of caries despite the in creased sale and use of toothbrushes and dentifrices. The reasons for this incon sistency are that the toothbrush has not been used at the time of greatest effec tiveness nor in the manner that cleanses the areas that are vulnerable to decay. Present knowledge indicates that the de-
18. Lederle Laboratories. The dental care o f children, 1953.
K E S E L . . . V O L U M E 52. A P R IL 1956 • 459
Table
D iet suggested fo r caries reduction
Bread (with butter)
Breakfast Do eat W h o le w heat, dark rye, Swedish, zw ieback, Ry-krisp
Do n o t eat W h ite brea d , doughnuts, Danish pastry, buns,- o r spreads such as jellies o r jams
Cereals
C orn flakes, puffed rice, etc. w ith milk o n ly
Sugar
Eggs
Any style; bacon, sausage, French to a st w ith butte r
Syrup
Fruits, juices
W h o le fru it o r fresh, frozen o r un sw eetened canned juice o f orange, g ra p e fru it; h oneydew melon, cantaloupe
Prunes, a prico ts, figs
C h o c o la te o r o th e r fla v o re d milk
M ilk
8 oz. (plain)
W a te r
6 oz.
Soups, juices
Lunch Fresh o r canned soups, v e g e ta b le juices
Sandwiches
Lettuce, tom a to , peanut butter, o r co ld cuts on brea d products m entioned a b o ve , w ith b utte r
Salads
Tossed salads, hearts o f lettuce, o r sal ads o f fin e ly g round vegetables w ith dressing
Desserts
Apples, oranges, tangerines,- fresh p in e a pple
M ilk
8 oz. (plain)
W a te r
6 oz.
Jellies, honey, etc.
Cakes, cookies, bananas, plums, dates o r d rie d fruits
S w eet c a rb o n a te d drinks Dinner
Soup o r juice
Same ch oice as lunch
A pp etize rs
Clams, oysters, shrimp, chicken liver, etc.
M eats, fish
Beef, lamb, pork, ve a l, liver, fo w l, o r fish
V egetables
Salads
Fried rice o r egg noodles, string beans, co oke d ca rrots, p o ta to chips, cabbage, spinach, c a u liflo w e r Same ch oice as lunch
Desserts
Same ch oice as lunch
M ilk
8 oz. (plain)
W a te r
6 oz. Betw een-m eal snacks M ilk Bread and butte r C orn chips Potato chips Popcorn O ranges Apples C a rro ts H earts o f lettuce o r cabbage C e le ry M e a t sandwiches
Ice cream, puddings, cakes, cus tards, pies, cookies
C andy Ice cream C hew ing gum Raisins Jellies S w eetened drinks o r o th e r items m entioned
460 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
calcifying phase of the carious process reaches its maximum activity within the first 20 to 30 minutes after eating; there fore, the popular habit of brushing teeth the first thing in the morning and the last thing at night is not rational for caries control. People should be taught to clean the mouth soon after eating. The way in which teeth are brushed is very important. Too often, particularly in children, the toothbrush comes into con tact with only the prominent surfaces of the teeth— those areas that are naturally cleansed in mastication. Disclosing solu tions should be applied to the teeth so that the individual can see where plaques of bacteria and debris accumulate in his own mouth; he is then better able to remove the plaques as a routine proce dure. The plaque accumulation pattern varies with each individual. If he can see these plaques revealed by the dye, he can learn to care for his mouth much more efficiently. Various dentifrices have been designed to inhibit bacterial or enzymatic activity, or to neutralize the acids that are formed after eating. Evidence is conflicting as to whether such additives in dentifrices are helpful in reducing caries activity. In vestigations to determine the effective ness of dentifrices for controlling caries are extremely hard to conduct, and re sults are difficult to interpret. Some of the obstacles are the necessity for a large number of subjects, the long time inter val of study, the difficulty of obtaining conscientious cooperation or close super vision of the subjects, proper application of the material and adequate measure ment of the effect of the brush alone. Then, too, the effectiveness of a dentifrice undoubtedly is mitigated by the cariogenic potency of many diets. It is reason able to believe that a dentifrice with anticarious properties would be more effective in a total caries control program than when employed alone as the only controlling agent. Further investigation of dentifrices for caries control is neces
sary to measure their effectiveness con clusively. It would be naïve to believe that in the foreseeable future the initiation of new carious lesions will be completely checked. For years ahead the preserva tion of many teeth from carious destruc tion will come only through good opera tive dentistry, started early and maintained at regular intervals. Better programs for the detection of early lesions in children, and their prompt elimination by proper fillings, will be most successful in reducing the number of dental cripples that now walk into dental offices. The loss of permanent teeth in chil dren and young adults is shocking. It is estimated that 40 per cent of children in the United States have had at least one permanent tooth extracted by the age of 14; that at age 35, a quarter to a half of the population has or should have artificial dentures. In Figure 1, left, a beginning lesion can be seen in the occlusal surface of a lower molar in an 11 year old individual. Figure 1, right, shows the condition two years later. Evidently the neglected cavity had progressed to a point at which a dentist felt compelled to extract the molar. This subject was one of several hundred children under observation in a two year oral hygiene study. Figure 2, left, shows the condition in another child in this study. Extensive caries can be seen beneath the occlusal enamel in both upper and lower first molars at age 11. Two years later (Fig. 2, right) both first molars were missing and the bicuspids were drifting. Figure 3 demonstrates the importance of the early detection and treatment of carious areas. Figure 3, left, shows an instance in which the central occlusal pits in the first molars were filled before the child was 14 years of age. Figure 3, right, shows no further carious destruction when the patient had reached age 17. It may be enlightening to contrast oral
K E S E L . . . V O L U M E 52, A P R IL 1956 • 461
Fig. 1 • L e ft: Early occlu sal caries in low er first molar in 11 year old child. R ight: Same child, two years later. First molar is missing
Fig. 2 ' L e ft: E xtensive caries undermining occlusal surfaces in upper and lower first molars o f 11 year old child. R ig h t: Same indi vidual, two years later. First molars have been extracted and teeth are shifting
Fig. 3 • L e ft: Early caries in occlusal pits, properly treated. R ig h t: Same teeth four years later. Caries checked
conditions in the school children of Nor way with those in the United States. Since 1910 a school dental program has been conducted in Oslo, Norway, in which the children are provided annually with dental care. Upon graduation from high school, dental treatment is available only in private offices under circum stances similar to those in the United States. A survey was made and reported by Carl Sebelius,19 dental director of the Tennessee State Health Department, on the oral health of children residing in Oslo. There were 296 13 year old chil dren in the group reported. When the results of his examinations are compared with those obtained from similar exami nations of 370 13 year old children in Richmond, Ind., carried out under the
direction of Waterman and Knutson of the United States Public Health Service, a considerable difference is noted20 (Fig. 4 ) . The rate of caries attack as indicated by decayed and filled teeth was reported to be approximately the same in Rich mond as in Oslo— 9.05 carious teeth per Oslo child to 8.87 carious teeth per Rich mond child. This similarity in attack in dicates that any dietary difference ap parently had little effect on the incidence of caries. In Oslo, the unfilled carious teeth, that is, the open, untreated lesions— averaged
19. Sebelius, C. L. Trends in preventive dentistrv in the United States and Scandinavia. J . Am . C ol. Den. 19:313 Sept. 1952. 20. Waterman, G . E., and Knutson, J. W . Studies on dental care services fo r school children. First and second treatm ent series, Richmond. Ind. Pub. Health Rep. 68:583 June 1953.
462 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
I
Richmond ■ 1.00
I Filled teeth
r ~ i Unfilled carious teeth
Oslo 8.55
■■
:*‘M
Extracted teeth per child Richmond 1.46
:
?
7.41 0 .5
[O slo .06
F ig. 4 • D M F co m p a riso n o f O slo , N o rw a y , and R ich m o n d , I n d ., ch ild ren , 13 years old
only 0.5 tooth per child as contrasted with approximately 7.5 teeth per Rich mond child. Conversely, there was a con siderable difference in the number of filled teeth— 8.5 filled teeth in the aver age 13 year old Oslo youngster to only 1.5 filled teeth for the Richmond child of the same age; but the great signifi cance comes in the comparison of ex tracted permanent teeth: in Oslo, the average was 6 teeth per 100 children whereas in Richmond the average was 100 teeth per 100 children, or one permanent tooth per child. If more effort is not put into remedial dental service for children, the United States will continue to reap in adults the results of disorganized child care. COM M ENT
Teeth are adult structures that erupt into the mouth long before the child is capable of appreciating their adult sig
nificance. Parents too frequently and for numerous reasons do not show the neces sary concern. Therefore, dentists, who should more fully appreciate the value of sound teeth and a complete dentition than anyone else, should concentrate on planning better dental care programs for children. They should make the public more conscious of the ultimate value of such service and they should inaugurate, direct and participate in more such pro grams at community levels. It is generally agreed that it is right and proper for every child to receive a certain amount of education. Laws re quire that during his crucial formative years each child must attend school until he is 16 years old. Health and appearance are as important to the child as is educa tion. Should not dentists insist that pro grams be established that will utilize pre ventive skills in a remedial way and that will preserve for adult life great numbers of the teeth that are now being ruined during childhood? The greatest advance in dental public health can come from the widespread development of such pro grams. Nothing new has been revealed in this brief review of caries etiology, prevention and control. Its purpose is to reaffirm faith in what is known and to accelerate more action in its application so that fu ture generations will be served more by their own teeth and less by the artificial variety. Incidentally, this result would be the best long range solution to the prob lems concerning the dental technician and the illegal dental laboratory.
N othing Is Im possible • T h e steadily rising tide o f technical knowledge has a way o f obliterat ing obstacles so effectively that w hat seemed impossible to one generation becomes elementary to the next. A rthur C. Clarke.
Approximately 90 per cent of the teeth now lost before middle age could be saved in the future adult population of this country by the application of what is already known about the control and prevention of dental diseases. A major problem is to find the means and the will for applying what is known. The public health dentist can play a major role in the solution of that problem. Teeth are lost for two principal reasons: ( 1) destruction of the crowns by caries and ( 2) destruction of the at taching tissues by inflammation and de generation. Although not all the intricate complications in the etiology of caries have been unraveled, sufficient under standing of the basic factors has been gained to place preventive treatment on a rational basis; and the possibility of con trolling the progress of carious destruc tion through good operative dentistry at an early age is well established. The fac tor most often responsible for periodontal destruction is inflammation that can be traced to some local irritation. Early recognition of deviations from normal color, contour and texture of the gingiva, and institution of proper treatment to alleviate these symptoms, could result in tremendous reduction in the loss of teeth.
port the generally accepted theory that bacterial activity is a major factor. The fact that cavities invariably occur where microorganisms can accumulate and re main relatively undisturbed for long periods of time has provided circumstan tial evidence that bacteria are associated with the destructive process. Direct evi dence that bacteria are required for the production of caries is accumulating through the germfree animal studies con ducted at the University of Notre Dame in collaboration with the Zoller Clinic of the University of Chicago.2 Ordinary rats fed a caries-producing diet develop a high incidence of this disease. Germfree animals fed the same diet develop no carious lesions. Further evidence show ing the importance of the local environ ment, including the bacterial flora, has been obtained by stomach tube feeding of rats.3 When a caries-producing diet is placed in the stomach by this method, so that it does not come into contact with the teeth in passing through the mouth, no carious lesions develop. The principal agent that destroys the calcified tissues of the teeth is probably acid in character. Many investigations4 have demonstrated the production of
P R IN C IP A L C A U S A T IV E F A C T O R S
Departm ent o f app lie d materia medica and thera peutics, University o f Illinois C ollege o f Dentistry. 1. Kesel, R. G . Dental caries: etiology, control and a ctivity tests. J.A .D .A . 30:25 Jan. 1943. 2. O rland, F. J .t and others. Use of the germfree animal technic in the study o f experim ental dental canes. I. Basic observations on rats reared free o f all microorganisms. J. D. Res. 33:147 A p ril 1954. 3. Kite, O . W .; Shaw, J. H .t and Sognnaes, R. F. An influence on dental caries incidence produced in rats by tube feeding. (A bst.) J. D. Res. 29:668 O ct. 1950. 4. National Research C ouncil. Survey of the literature of dental caries. Washington, D. C., National Academy of Sciences, 1952.
There are many predisposing conditions that may influence the carious process such as age, heredity, emotions, state of health, salivary flow and composition, tooth structure and position, but the actual destructive forces are few .1 Evi dence continues to accumulate to sup 455
456 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
cavities in the enamel by weak acids. Recent experiments, under artificial con ditions, have produced early lesions in the enamel that are indistinguishable from lesions that develop in the oral cavity.5,6 The agents used to produce these lesions under laboratory conditions are acid. There is no instance in which anything resembling typical carious lesions has been produced artificially with nonacid substances. Several investi gators have shown that when the tooth tissues are subjected to alkaline agents or proteolytic enzymes, no readily demon strable effect appears.7'9 If tooth tissues are exposed to a weak acid so that some décalcification takes place, then enzymes such as trypsin, pepsin or collagenase can exert a destructive action. Apparently, the carious process requires both acidic and enzymic components, and the natural carious process is probably one of intermittent periods of décalcification followed by lytic decomposition. An association between acid produc tion in the oral cavity and carious ac tivity has been shown in numerous studies. Several investigators have found that if a caries-susceptible person rinses his mouth with a. glucose solution, the potentiometer readings made with suit able electrodes to determine acid forma tion indicate that sufficient acid is formed on the tooth surface within a few minutes to be potentially harmful to the calci fied tissues.10-12 Individuals not suscept ible to caries show no such acid produc tion. Recent studies in which an indicator dye, methyl red, was used also showed acid conditions in carious regions.13,14 This dye changes in color from yellow to red as acid is formed. When applied to the surfaces of the teeth after a sugar rinse, red coloration de velops in the areas where the carious de struction appears to be taking place. This method is being studied currently in the hope of developing a simple caries-activity test that can be used in the dental office to demonstrate to the patient con
ditions in his own mouth. The long recog nized association of acidogenic and aciduric bacteria with active caries is further circumstantial evidence of the importance of the acid factor. The only type of food taken into the mouth which can develop an acidity of sufficient strength to dissolve enamel is carbohydrate. The carbohydrates are converted to acid by enzymatic action. The simpler the carbohydrate, the more rapidly is it converted to acid. Thus, the simple sugars— glucose, fructose, sucrose — are more readily converted than are the polysaccharides— the starches. Many dietary studies have shown an association between refined carbohydrate consump tion and caries activity. It is well known that the amount of caries any population experiences is roughly proportional to its sugar consumption. It is important that experimental caries cannot be produced in laboratory animals unless the diet con tains a readily fermentable fraction. CONTROL
OF
C A R IE S
When these observations are collated— that is, the association between bacteria, carbohydrates, the production of acids
5. Weîsberger, D. Role o f glucose in production of a rtific ia l caries. J. D. Res. 29:14 Feb. 1950. 6. Dreîzen, S., and Spies, T. D. D écalcification and discoloration of intact, non-carious human tooth crowns by an oral strain of Lactobacillus acidophilus. Oral Surg., O ral Med. & O ral Path. 4:388 March Î95I. 7. pannenberg, J. L., and Bibby, B. G. E ff e c t if zinc chloride and potassium ferrocyanide on proteolysis. J. D. Res. 29:177 A p ril 1950. 8. Engel, M . B. Softening and solution o f the dentin in caries. J.A .D .A . 40:284 March 1950. 9. Frank, M. R. Etiology o f dental caries. Décalcifica tion by acids: can it be the orig in a l cause of dental caries? L'înform atîon-dent. 33:7, 1951. 10. Stephan, R. M. Intra-oral hydrogen-ion concentra tions associated with dental caries activity. J. D. Res. 23:257 Aug. 1944. 11. Fosdick, L. S.; Campaigne, E. E., and Fancher, O. Rate o f acid form ation in carious areas. The etiology of dental caries. Illinois D. J. 10:85 March 1941. 12. Stralfors, A lla n. Investigations into the bacterial chemistry of dental plaques. Stockholm, Tryckeri A.-B. Thule, 1950. 13. Hardwick, J. L., and Manley, E. B. Caries o f the enamel. II. Acidogenic carles. Brit. D. J. 92:225 May 6, 1952. 14. Arnim , S. S., and Hardwick, J. L. C lin ica l demon strations o f acid production by mouth organisms using aqueous methyl red. North-W est Den. 33:147 May 1954.
K E S E L . . . V O L U M E 52, A P R IL 1956 • 457
from bacterial action on carbohydrate and the requirement of acid for tooth destruction— it is obvious what the prin cipal factors in tooth destruction are and what steps can be taken to prevent or control this disease. A rationale based on the factors outlined for reducing carious activity could include the following: 1. Restriction of the amount of fer mentable carbohydrate in the diet. 2. Production of a tooth tissue more resistant to acid and enzymatic action. 3. Removal of fermentable material from the surfaces of the teeth before it is converted into acid. 4. Employment of nontoxic antibac terial agents to eliminate the micro organisms associated with the decay proc ess or to interfere noticeably with their metabolism. 5. Placement of inhibitors in the mouth that interfere with or destroy the enzymes responsible for the conversion of carbohydrate to acid. 6. Neutralization of acids as rapidly as they are formed on the tooth surfaces. The most effective means of prevent ing the initiation of carious lesions is a dietary program that sharply reduces the amount of sugar consumed. If refined sugar could be removed from the diet, the caries problem would be eliminated. In the United States in the neighborhood of 100 pounds of sugar per person per year is consumed. Twenty-five to 40 pounds of sugar per year would be suf ficient to supply all the calories that are needed from a carbohydrate source for good nutrition.15 The excess 60 to 75 pounds of sugar is detrimental for several reasons. It is producing a state of malnu trition, particularly among children, be cause it is a great appetite appeaser. It, like alcohol, contributes little to nutrition outside of caloric energy. Yet it is a com mon article of diet, particularly between meals, lessening the appetite for more nu tritious material at mealtime. A report by a major candy manufacturer indicated that the annual consumption of candy
for 1950 was 17 pounds per person.16 The candy consumption was compared audaciously with that of butter, cheese and other products of high nutritional value. The article stated that the annual consumption of butter was ten pounds and of cheese seven pounds per person. The combined consumption of butter and cheese barely equaled that of candy. If the leaders of the candy industry of this country are proud of their ac complishment, they should look at Britain’s record. The British cocoa, chocolate and confectionery alliances have reported that, since candy was dera tioned, Britons lead the world, consum ing at the rate of 26 pounds per person annually. Such comparisons indicate the tremendous amount of material being eaten to satisfy appetite without provid ing good nutrition. Sugar consumption is producing obesity in some children and certainly in the adult population, as well as providing ammunition for the carious process in both. It may lead to vitamin B complex deficiency because of the need for this vitamin in the metabolization of useless calories. Much of the excess sugar is being taken in forms such as bottled beverages, chewing gum, pastries and jams that the population does not regard as sugar. Too many think of sugar only as the crystallin form in the sugar bowl. An evaluation of the sugar content of various items that are popularly con sumed has been published in t h e j o u r n a l
OF
T H E
A M E R IC A N
D EN TAL
A S S O C IA
Mimeographed copies of that list are available through some state health departments. They should be given to patients in whom caries control is being attempted. Nearly all will express amaze ment at the sugar content that is not T I O N . 17
15. Massler, Maury, and Zwemer, J. D. Rampant caries. (Its clinical management.) Illinois D. J. 20:407 Sept. 1951. 16. Drug News, Sept. 1950, p. 23. 17. Brauer, J. C. M astication the detergent, the adequate and the low-sugar diets; their effects on dental caries. J.A .D .A . 39:682 Dec. 1949.
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apparent to the consumer; for instance, seven teaspoons of sugar in a candy bar; four to five teaspoons in a bottle of soft drink and 14 teaspoons of sugar in a piece of cherry pie. Although management of caries through dietary channels may be difficult, an attempt certainly should be made to improve nutrition and to reduce caries by moderation in sugar consumption. Diet histories should be taken over a period of at least one week, and specific attention should be drawn to items in the diet that are high in sugar. It is not enough to request the reduction or re moval of such items from the diet. Satis factory substitutes should be emphasized. For in-between-meal snacks, nuts, pop corn, potato chips, cheese and other items that are appetite-appeasing but not readily fermentable, should be recom mended. Sample menus should be pro vided for breakfast, lunch, dinner and in-between-meals ; items to be avoided and those to be eaten should be listed. A sample of such menu recommendations has been provided by the Lederle Labora tories in one of its pamphlets on dental health.18 Copies of it, with some modi fications made by the author, have been found helpful in caries control work (table). It must be recognized that there are strong economic and psychological dis advantages in attempting the control of caries by sugar restriction. Sugars are palatable, readily available, widely ad vertised and economical as a source of caloric energy. Individuals— even den tists— like their sweets, and that is one reason greater professional emphasis is not placed on this effective means of con trol. Some dentists hesitate to recom mend vigorously what they themselves do not practice. This practical disad vantage necessitates consideration of other means for reducing caries activity. Another effective means, with suffi cient evidence to support the claims for it, is the use of fluorides either through
water fluoridation or topical application of fluoride solutions. Any means for caries control that requires conscientious co operation on the part of the individual, that denies him something which he en joys or requires him to perform a ritual that is inconvenient, cannot be too effec tive in controlling caries in large num bers of people. But an agent that will give partial resistance and that can be provided without personal effort on the part of the individual is fluoridation of the drinking water. It should be an effec tive mass means of reducing caries. The disadvantage that may come from such an easy way is, perhaps, the implicit re liance on fluorine in the drinking water to give complete protection against car ies. If water fluoridation develops a false sense of security that encourages in creased sugar consumption and relaxed oral hygiene, perhaps more harm than good may result from water fluoridation, at least for some people. It should be emphasized always that fluorine is not a complete protector; that in communi ties where fluorides are present in op timal amounts in the drinking water, there is still much tooth decay. The same vigilance as to other measures for caries control is required, and periodic exam ination and restoration of the cavities that will develop are essential if water fluoridation is to obtain its maximum result. For many years the toothbrush has been advocated as a weapon against caries. Skepticism has developed about its effectiveness because of the increas ing incidence of caries despite the in creased sale and use of toothbrushes and dentifrices. The reasons for this incon sistency are that the toothbrush has not been used at the time of greatest effec tiveness nor in the manner that cleanses the areas that are vulnerable to decay. Present knowledge indicates that the de-
18. Lederle Laboratories. The dental care o f children, 1953.
K E S E L . . . V O L U M E 52. A P R IL 1956 • 459
Table
D iet suggested fo r caries reduction
Bread (with butter)
Breakfast Do eat W h o le w heat, dark rye, Swedish, zw ieback, Ry-krisp
Do n o t eat W h ite brea d , doughnuts, Danish pastry, buns,- o r spreads such as jellies o r jams
Cereals
C orn flakes, puffed rice, etc. w ith milk o n ly
Sugar
Eggs
Any style; bacon, sausage, French to a st w ith butte r
Syrup
Fruits, juices
W h o le fru it o r fresh, frozen o r un sw eetened canned juice o f orange, g ra p e fru it; h oneydew melon, cantaloupe
Prunes, a prico ts, figs
C h o c o la te o r o th e r fla v o re d milk
M ilk
8 oz. (plain)
W a te r
6 oz.
Soups, juices
Lunch Fresh o r canned soups, v e g e ta b le juices
Sandwiches
Lettuce, tom a to , peanut butter, o r co ld cuts on brea d products m entioned a b o ve , w ith b utte r
Salads
Tossed salads, hearts o f lettuce, o r sal ads o f fin e ly g round vegetables w ith dressing
Desserts
Apples, oranges, tangerines,- fresh p in e a pple
M ilk
8 oz. (plain)
W a te r
6 oz.
Jellies, honey, etc.
Cakes, cookies, bananas, plums, dates o r d rie d fruits
S w eet c a rb o n a te d drinks Dinner
Soup o r juice
Same ch oice as lunch
A pp etize rs
Clams, oysters, shrimp, chicken liver, etc.
M eats, fish
Beef, lamb, pork, ve a l, liver, fo w l, o r fish
V egetables
Salads
Fried rice o r egg noodles, string beans, co oke d ca rrots, p o ta to chips, cabbage, spinach, c a u liflo w e r Same ch oice as lunch
Desserts
Same ch oice as lunch
M ilk
8 oz. (plain)
W a te r
6 oz. Betw een-m eal snacks M ilk Bread and butte r C orn chips Potato chips Popcorn O ranges Apples C a rro ts H earts o f lettuce o r cabbage C e le ry M e a t sandwiches
Ice cream, puddings, cakes, cus tards, pies, cookies
C andy Ice cream C hew ing gum Raisins Jellies S w eetened drinks o r o th e r items m entioned
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calcifying phase of the carious process reaches its maximum activity within the first 20 to 30 minutes after eating; there fore, the popular habit of brushing teeth the first thing in the morning and the last thing at night is not rational for caries control. People should be taught to clean the mouth soon after eating. The way in which teeth are brushed is very important. Too often, particularly in children, the toothbrush comes into con tact with only the prominent surfaces of the teeth— those areas that are naturally cleansed in mastication. Disclosing solu tions should be applied to the teeth so that the individual can see where plaques of bacteria and debris accumulate in his own mouth; he is then better able to remove the plaques as a routine proce dure. The plaque accumulation pattern varies with each individual. If he can see these plaques revealed by the dye, he can learn to care for his mouth much more efficiently. Various dentifrices have been designed to inhibit bacterial or enzymatic activity, or to neutralize the acids that are formed after eating. Evidence is conflicting as to whether such additives in dentifrices are helpful in reducing caries activity. In vestigations to determine the effective ness of dentifrices for controlling caries are extremely hard to conduct, and re sults are difficult to interpret. Some of the obstacles are the necessity for a large number of subjects, the long time inter val of study, the difficulty of obtaining conscientious cooperation or close super vision of the subjects, proper application of the material and adequate measure ment of the effect of the brush alone. Then, too, the effectiveness of a dentifrice undoubtedly is mitigated by the cariogenic potency of many diets. It is reason able to believe that a dentifrice with anticarious properties would be more effective in a total caries control program than when employed alone as the only controlling agent. Further investigation of dentifrices for caries control is neces
sary to measure their effectiveness con clusively. It would be naïve to believe that in the foreseeable future the initiation of new carious lesions will be completely checked. For years ahead the preserva tion of many teeth from carious destruc tion will come only through good opera tive dentistry, started early and maintained at regular intervals. Better programs for the detection of early lesions in children, and their prompt elimination by proper fillings, will be most successful in reducing the number of dental cripples that now walk into dental offices. The loss of permanent teeth in chil dren and young adults is shocking. It is estimated that 40 per cent of children in the United States have had at least one permanent tooth extracted by the age of 14; that at age 35, a quarter to a half of the population has or should have artificial dentures. In Figure 1, left, a beginning lesion can be seen in the occlusal surface of a lower molar in an 11 year old individual. Figure 1, right, shows the condition two years later. Evidently the neglected cavity had progressed to a point at which a dentist felt compelled to extract the molar. This subject was one of several hundred children under observation in a two year oral hygiene study. Figure 2, left, shows the condition in another child in this study. Extensive caries can be seen beneath the occlusal enamel in both upper and lower first molars at age 11. Two years later (Fig. 2, right) both first molars were missing and the bicuspids were drifting. Figure 3 demonstrates the importance of the early detection and treatment of carious areas. Figure 3, left, shows an instance in which the central occlusal pits in the first molars were filled before the child was 14 years of age. Figure 3, right, shows no further carious destruction when the patient had reached age 17. It may be enlightening to contrast oral
K E S E L . . . V O L U M E 52, A P R IL 1956 • 461
Fig. 1 • L e ft: Early occlu sal caries in low er first molar in 11 year old child. R ight: Same child, two years later. First molar is missing
Fig. 2 ' L e ft: E xtensive caries undermining occlusal surfaces in upper and lower first molars o f 11 year old child. R ig h t: Same indi vidual, two years later. First molars have been extracted and teeth are shifting
Fig. 3 • L e ft: Early caries in occlusal pits, properly treated. R ig h t: Same teeth four years later. Caries checked
conditions in the school children of Nor way with those in the United States. Since 1910 a school dental program has been conducted in Oslo, Norway, in which the children are provided annually with dental care. Upon graduation from high school, dental treatment is available only in private offices under circum stances similar to those in the United States. A survey was made and reported by Carl Sebelius,19 dental director of the Tennessee State Health Department, on the oral health of children residing in Oslo. There were 296 13 year old chil dren in the group reported. When the results of his examinations are compared with those obtained from similar exami nations of 370 13 year old children in Richmond, Ind., carried out under the
direction of Waterman and Knutson of the United States Public Health Service, a considerable difference is noted20 (Fig. 4 ) . The rate of caries attack as indicated by decayed and filled teeth was reported to be approximately the same in Rich mond as in Oslo— 9.05 carious teeth per Oslo child to 8.87 carious teeth per Rich mond child. This similarity in attack in dicates that any dietary difference ap parently had little effect on the incidence of caries. In Oslo, the unfilled carious teeth, that is, the open, untreated lesions— averaged
19. Sebelius, C. L. Trends in preventive dentistrv in the United States and Scandinavia. J . Am . C ol. Den. 19:313 Sept. 1952. 20. Waterman, G . E., and Knutson, J. W . Studies on dental care services fo r school children. First and second treatm ent series, Richmond. Ind. Pub. Health Rep. 68:583 June 1953.
462 • T H E J O U R N A L O F T H E A M E R I C A N D E N T A L A S S O C I A T I O N
I
Richmond ■ 1.00
I Filled teeth
r ~ i Unfilled carious teeth
Oslo 8.55
■■
:*‘M
Extracted teeth per child Richmond 1.46
:
?
7.41 0 .5
[O slo .06
F ig. 4 • D M F co m p a riso n o f O slo , N o rw a y , and R ich m o n d , I n d ., ch ild ren , 13 years old
only 0.5 tooth per child as contrasted with approximately 7.5 teeth per Rich mond child. Conversely, there was a con siderable difference in the number of filled teeth— 8.5 filled teeth in the aver age 13 year old Oslo youngster to only 1.5 filled teeth for the Richmond child of the same age; but the great signifi cance comes in the comparison of ex tracted permanent teeth: in Oslo, the average was 6 teeth per 100 children whereas in Richmond the average was 100 teeth per 100 children, or one permanent tooth per child. If more effort is not put into remedial dental service for children, the United States will continue to reap in adults the results of disorganized child care. COM M ENT
Teeth are adult structures that erupt into the mouth long before the child is capable of appreciating their adult sig
nificance. Parents too frequently and for numerous reasons do not show the neces sary concern. Therefore, dentists, who should more fully appreciate the value of sound teeth and a complete dentition than anyone else, should concentrate on planning better dental care programs for children. They should make the public more conscious of the ultimate value of such service and they should inaugurate, direct and participate in more such pro grams at community levels. It is generally agreed that it is right and proper for every child to receive a certain amount of education. Laws re quire that during his crucial formative years each child must attend school until he is 16 years old. Health and appearance are as important to the child as is educa tion. Should not dentists insist that pro grams be established that will utilize pre ventive skills in a remedial way and that will preserve for adult life great numbers of the teeth that are now being ruined during childhood? The greatest advance in dental public health can come from the widespread development of such pro grams. Nothing new has been revealed in this brief review of caries etiology, prevention and control. Its purpose is to reaffirm faith in what is known and to accelerate more action in its application so that fu ture generations will be served more by their own teeth and less by the artificial variety. Incidentally, this result would be the best long range solution to the prob lems concerning the dental technician and the illegal dental laboratory.
N othing Is Im possible • T h e steadily rising tide o f technical knowledge has a way o f obliterat ing obstacles so effectively that w hat seemed impossible to one generation becomes elementary to the next. A rthur C. Clarke.