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An evaluation of recent developments in caries control
AN EVALUATION
OF RECENT DEVELOPMENTS
IN CARIES CONTROL
ESEARCH reported in the past two ~-cars 1~~ im1)rovta(l 011~untlerstanding It has given adtliof the effectiveness of srvrral varies wntrol I)rwedurcs. tional support to some’ illlY~It1~~ acwptct-1 iucthotls and has ~~lawtl in the (laestionable rategor!, some of t tie more rrt:entl~- advanvetl theories. I have attempted to classify the methods that have been given major al tent ion into three groups : first, those for which suffkient eritlence has acwmulated to indicate that the) are acceptable procedures: seconcly those for whirl1 there is evidence for their usefulness, but for which further research is necessary ; and, third. those methods which past experience and research hare labeled unacceptable. The classification is based on my analysis of published data and with the realization that personal I have arranged the evaluation in Table I for appraisal is subject to error. I have outlined clarity? to stimulate diwnssion, and for correction. if wrong. some of t.lie advantages and disadvantages of each provedwe. The most effect,ive way of controlling dental caries, in my opinion, is through eonwientious reduction in sugar eonsuml)tioii. Evidcnw has continued to atht*umutate to indict sugar as a major c.IllI)rit it1 tltr ~~rodwtit~~~ of wvities. Studies ~vII human beings, 011 t.aries-s;usc.t~l)t,il)le animak :lS Well its 1~l\NJlatO~‘\~ t’\ideIWc. sl~o\v ttir inipt)rtani relationstliI) twtxwll sllgr WJIlSllIll~~ti~Jli iln(l t*ilriW prodlit’1ion. between sugar elimination anti earics wstriction.
R
440
ROBERT G. KESEL
about the role of carbohydrates and acidogenic bacteria in caries production. The work in being done in collaboration between Notre Dame University and the Zoller Dental Clinic of the Universit.y of C’hicago. L4 method has been developed for delivering and raising rats in a bacteriafree environment. It has progressed to the point where the bacteria-free rats have been fed a diet that produces a high incidence of dental caries in the control animals. Personal communication with the workers tells us that no caries develops in the bacteria-free animals on this diet. St,udies are now underway in which the food supplied the sterile animals is contaminated with a pure strain of an acidogenic organism. one of the lactobacilli obtained from the oral cavity of an individual highly susceptible to caries. The purpose of this procedure, of course, is to determine the possibility of producing caries by the interaction of the diet and the single bacterial species in the rat mouth under these strictly controlled conditions. I believe this study, while slow and difficult, will make a most important contribution to our understanding of the caries etiology. TABLE
I.
CARIES I
I ! *L. Reduce
c'0r;rp.o~ ADVANTAGES
sugar-’ intake a.7== (especially b e t m e e n b. Improved meals)
and,'or Brush teeth rinse mouth immediately after eating
Topical
of mater 7C~tluction b. Mass control
2. hmmoniate~l
dentifrice,
Tooth impregnation a. Zinc chloride b. Silver nitrate Penicillin
(8) method
a. Caries reduction ( 8) b. Use of (‘natural” antibiotic
tlentifrice
Caries
re:luction
Caries
retluction
1. Calciumtherapy
1.
2. Vitamin
therapy
2.
Fluoride
tablets
4. Synthetic 5. Glyceric
Vitamin aldehyde
Because K
J
3. 4. 5.
Mass cooperation ficult b. Economy a. Inconvenience discipline b. Rigid quired
a. Caries reduction (8) cooperation 1). Patient unnecessary
dentifrice
I.a. Chlorophyll I
__IUNA%c~i3~~~~t3.
a. Caries reduction 1,. Clean mouth
application of a. Caries reduction fluoride b. Simplicity
Fluoridation
DISADVANTAOES
I
-/a. nutrition
(8)
dif-
re.
a. Not a mass control method dental ap,h. Requires . . pomtments Not yet proved / Rigid
discipline
required
a. Causticity b. Discoloration c. Time consuming a. Sensitization b. Drug fastness required c. Discipline
Rigid discipline required C? not related to calcium metabolism Caries is a dietary, not nutritional disease Not absorbed by completed enamel Toxicity Toxicity (8)
A distinct advantage in reducing sugar consumption is not only the possibility of reclucing caries activity but also of improving nutrition. The sugar used in 1~11ms1n cn!!qll.mption provides only calories and no other nutrient and in addi-
RECENT
DEVELOPJIENTS
IS
(‘ARIES
CONTROL
441
tion it is a great appetite appeaser. I was startled by a report published during the past )-ear by Dr. E. Taylor I)ykes.2 Ht: reported a survey that was made bp questionnaire of 23!000 school children in Oakland, Calif. It re\.ealed the follow ing : IS.8 per cent had candy before 9 a.m. 35.1 per cent had candy before 1 p.m. 6.1 per cent had soft drinks before 9 a.m. 15.3 per writ had soft drinks before I p.m. Fifty-four per cent of ( )aklancl school ehilclwn habitually- consumed can+ or soft drink before 1 p.m. and thesr were prohahly the children with a lo\\ total of basic physiologically required calories. The repla.cement of refined sugar calories with foods of substance will benefit nutrition as a whole. However, a realistic disadvantage to the control of dental caries by this desirable method is an uiicontrollable psyAiological one. sugar is sweet and sweetness always has a good connotation. The public appears to have greater regard for its sweet tooth than for its own natural teeth. Until there is developed a new psychological approach different from any now available, the large wale control of caries activity through sugar reduction is wishful thinking. For individuals yes; for the masses, no. Another obvious and serious clisaclranta,ge to this means is the economy They are, ot’ L’OLWS~, much less expensive provided by the use of carbohydrates. than the foocls that should be substittttetl in order to provide better nourishment along with caries reduction. It appears that sugar is here to sta).. and that we must. learn to live with it with iml)rovecl clental health.
During the first year of Dr. Fosdick’s stnd>-. the 526 test subjects showed il 1J.31.E’. recluc&tioti of 63 lwr w11t ~~~n~~~awcln-itti thcj IYI~I~rol group containing 306 subjects. The study was continuc,d a second year but the contrast between the test. and control groups xl-as not nearly as treat during the second-year ljeriod. During the second year the test sllh,jects hacl a reduction of 26 per cent
over the controls. The difYerrnce was not due to any lack of improvement in the test subjects, but rather to the fact that the controls showed a decided improvement in their caries experiellpe during the second year. It is suggested t.hat a pla~Gl)le reason Tar this improvement anlong the controls Iv-as an awareness that. they developecl of the value of oral h>-gienc performed soon after eating. So much publicity has been given to this procedure through various channels that individuals of college age might. be expected to change voluntarily their hygiene procedures. The results reported 1,. Dr. Fosdick have statistical significance and are the first controlled studies reporteti to justify the use of the toothbrush as a weapon against tooth decay. An advantage of this procedure in addition to caries control is the maintenance of a clean mouth. This feature should have a beneficial effect on other oral conditions and should provide an impetus for better mouth health. The disadvantages of this procedure, of course, are its inconvenience ancl the rather rigid discipline that it requires. Toothbrushing immediately after eating cannot be considered a conyeuient routine. Therefore, the discipline that would be requirecl to recluce caries incidence in large numbers of individuals will be difficult to obtain. There is suggestive evidence in Dr. Fosdick’s report that, rinsing the mouth vigorously with water immediately after eating fermentable material reduces the incidence of caries. He cited one college where the drinking fountain was close to the cand)- counter and less caries was obserrecl in this group who presumably- fotund it more convenient to rinse The possibilit,ies of flushing the mouth the mout.h after the sugar consumption. with water or with an antiseptic solution should be furt.her explored as such a procedure could be more easily aclopted than the habitual use of the toothbrush after eating. A third procedure for reducing ca.ries actirit>- that has receivecl general acceptance is the topical application of a 2 per cent sodium fluoride solution to the clean, dry tooth surface. Much evidence has accumulated through a number of studies by different, investigators indicating a caries reduct,ion of approxiXn adva.ntage of this method is mately 40 per cent t~hrough this procedure. A study recently made by the Illinois State Health its apparent simplicity. Department suggests t.hat the rather superficial prophylaxis that has usually preceded the topical application can be eliminated if the incliviclual will brush his teeth well for at least two weeks prior to the a.pplication. This stucly done on school children in Edwards County, Ill., indicates that the youngsters who brushed their teeth in the classroom twice each day over a two-week period prior to the application of the fluroide solution showed a reduction in caries at t,he encl of one year comparable to that observed in the group that, was given a prophylaxis by a clental hygienist. An earlier stud) had indicated that the topical application of fluorides to teeth that had not had a prophylaxis secured only half the protection. The reported fluorine studies do not indicate whether this preventive treatment is more effect.ive in controlling certain types of cavities than it is fol others. It. would be interesting to know whether or not the surfaces that are easily contacted with the fluoride solution are t,he ones that secure the greatest protect,ion.
RECENT
DEVELOPJIENTS
IN
C.%RIES
CONTROL
443
A study reported about a J-ear ago indicates that the areas of contact 01’ close approximation arc t.he ones least likely to be contacted by the topical application of a solution” The investigator, Dr. Kesic, tlemonstrated that ions or molecules of a solution diffuse with difficultp into the areas of contact between sl)herical solid bodies, be they teeth or steel balls? when they are immersed in a licluid. Al suggested reason for this lack of diffusion is a thinning out of the snllltiolr ill the area of wntact, resulting ilk a redwtion in the wncentration of ions in that area. IIis observations suggest that the nar~~\v pits, fissures, and the areas close to the contact point should be least protected by the tiuoride solution. Special effort would have to be made to contact these most, susceptible ;treas if the masimum protection is to be secured. This method, of course, requires dental al)pointments and the time of trained personnel which complicates its usefulness as a mass control method. The simplest methocl yet sugge&ed for reducing caries activity is the fluoridation of drinking water. According to the surveys made by the United Stat,es Public Health Service and others, children residing in areas where the drinking water contains approsiniately one part, per million of fluorides have about a 60 per cent lower caries experience rate. About six times as man\- children in these communities show no dental caries espcrience as do those in areas where the drinking water is fluoride free, and there is a decrease of i5 per cent in the loss of first permanent molars. A nnmber of studies hare been set 111)to determine whether or not the art,ificial fluoridation of the water supply in the test communities will obtain the same caries protective benefit without increasing an!- tosic manifestations. Hcwntl~~ :I rcpurt on one of the water fluoridation stntlics was published qi\.ing results observed during the first tlircc years.” The towls involwd in this rqvriment are IVcwl)urg and Kingston, 1cI. \-.. ( hi Ala?, 2. 194.5, the Newburg water supply had its flnorinc ~*Olltellt hrtbqkt ‘11’ tu 1.0-l .? p:irts 1JCr IIdliOll. The Kingston water snppl?- \vas left tlnorine ircra. Thvrc :I I’C al)l)roxirnatel~ :3,400 children under stud\- in Newlmrg and ?.S(JO c.tiildwn iii KingSton. ‘She clental rtsaniinations wcw rnatle with the aitl of !t)oLttli Illirrt)rs and sharp esplorers.
44-I
ROBERT
(:.
KESEI.
the approval of the state and local health authorities and the dental and medical professions. This recommeiiclatiotI has the npproral of the Unit,ed States Public Health Scr\+e for use where the community can meet and maintain the standards required b\, thr state health authority-. .I rewnt report has lwen made ol’ tlrth fifteewycar tluoridation study that. is under ~a?- in E’:anston. Ill., binder the direction of I)r. .J. R. Blayey.’ The examinations reported were made in the post-fluoride period from observations on 6- to S-)-ear-old children. These children showed an increase in the caries rate for the deciduous teeth during the post-fluoride period. However, statistical analysis indicated a marked reduction in the caries preralence in their permanent. teet.h. While the assumption wulcl he made that the sodium fluoride had greater effect on the permanent teeth than on the deciduous teeth because t.he permanent teeth had been exposed to the fluoride water for almost theil posterupt,ive life, Dr. Blayney felt that the trend is as he stated “far from conclusive. It cannot be assumed at this early time, and cannot be contributed to chance, that the changes that, hare taken place are necessarily clue to the addition of sodium fluoride. ’ ’ Dr. Blayney’s attit,ude is conservative, but 1)erhaps rightly so in riew of the fact that most all of those who are studying this phase of caries control agree that the long term studies under w-a>- should be concluded before final decisions can be clrawn. The use of ammoniated dentifrices l’or caries control has been considered in the previous paper. Another method for caries control that. has been widely used in the last few years is the so-callecl tooth impregnation technique advocated originally by Dr. Gottlieb. The rationale for this procedure as reported by its investigators is based on a different concept of caries etiology than the one more widely held which is based on the belief that the predominant destructive factor in cavit> production is the dissolution of the hard tooth ti.jsue b)- acid. The theory behind the tooth impregnation procedure is that t.he orp; lnic components of the teeth are initially at,tackecl by the carious process and provide inroads into the tooth A 20 per cent solution of pot.assium ferrocyanide tissue for bacterial invasion. is used to precipitate a 10 per cent solution of zinc chloride previously applied It is believed by the proponents of this techto the clean, dry tooth surface. nique that the organic st,ructures are so occluded by this impregnation with the zinc iron salt that bacteria can no longer enter them and that these organic structures are rendered less susrcptible to proteolysis. A check on the effectiveness of zinc chloride and potassium ferrocyanide in influencing the proteolysis of organic material has been reported during the past year.8 Coagulated egg albumin was exposed to the action of zinc chloride and potassium ferrocyanide and then to the action of the proteol-tic enzyme trypsin. It. a.ppeared from these studies that the zinc chloride-Ijotassium ferrocyanide enhanced the proteolysis rather than hindered it. Dentine specimens of extracted teet.1~were given an impregnation treatment and then were subjected to bhe action of trypsin. Normal dentine was not affected by tr,vpsin, but when
KEC‘EST
DEVELOP3IENTS
IN
CARIES
COljTROL
445
446
ROBERT
G. KESEL
Their disadvantages are that the: do rccluire the time and skill of tra,ined personnel for their application. Then, too, the)- are caustic and silver nit&e can produce a marked discoloration in the tooth tissue. It. was only logical followin g reported observations on the striking effect of pcnieillin on the oral bacterial flora to tind penicillin advocated as a cariesreducing agent. Preliminary studies done on laboratory animals showed t.hat when penicillin was contained in the drinking water or when the animals’ teeth were brushed with a penicillin-containin, w dentifrice, a reduct.ion in caries esperience was obtained.l’, I’: Early reports also indicated that when a penicillin dentifrice or mouthwash was used in the human oral cavity a reduction occurred in salivary lact,obacilli counts. IIowevert a study conducted on orphanage children using a penicillin dentifrice under unsupervised conditions produced no caries reductionl” A more recent report deals with 409 children who brushed their teeth under supervised conditions in the school classroom.‘” Two hundred thirty-fire ehildren brushed with a tooth powder containin g fiCI0 units of potassium penicillin per gram, 174 with a similar powder lacking in penicillin. The children brushed once daily in the school room and were instructed to brush at home morning and evening. The results of the study show an approximate decrease of 50 per cent in caries activity of those children who used the penicillin powder. These results indicate that the effect of the penicillin was significant. The problem of penicillin sensitivity- arises but according to the above report a minor amount of sensitivity was observed. Only t,wo children were dropped from the program because of what appeared to be an allergy to one or more ingredients of the tooth powder. Further studies were conducted on inmates of penal inst.itut,ions and private patients who used the penicillin dentifrice for three months. Twenty-eight or only 0.65 per cent showed manifestations similar to t.hose observed in the school study and the same conclusions were drawn, name1.v. that the majority of these manifestations were not related to the penicillin but were produced hy some other ingredient in the dentifrice. The usual estimate of the number of people sensitive to penicillin in the population is about 8 to 10 per cent, but, this percentage of reactions was in no way observed in this study. The usual manifestations of penicillin sensitivity through oral contact are soreness of the throat, and tongue, dryness of the lips, burning sensations t.hroughout the mouth, some impairment of taste, the development of esfoliatire lesions or fissures at the labial commissures. The rationale of penicillin t,herapy for caries control originally was predicated on its influence on the bacterial flora of the mouth. Contrary results were obtained in this stuciy.l” Despite the 50 per rent. reduction in clinical caries activity, there was no significant change in lactobaeilli counts. It. might be assumed that. this result WIY due to the development of penicillin-resistant lactobacilli. However, in some carefully done bacterial studies, it was found that there was no increase in the number of penicillin-resistant lactobacilli in the mouths of the children using the 1)enicillin dentifrice. It would seem that there must be some other explanation for the failure of the lactobacilli counts to eointide with the reduced caries activity.
RECENT
DEVELOPMENTS
IN
CARIES
CONTROL
447
The results to date indicate that penicillin may prove to be a useful means of combating tooth decay. However, the possibility of penicillin sensitivity and the production of penicillin-resistant organisms of the pathogenic variety other than lactobacilli must he carefully studied. Another antibiotic that may prove beneficial to oral health including reduced caries activity is ~~l~lo~~oI~l~~-ll.Vhlomphyll is the catalytic agent that I am sure .~.ou know brings al)out the photosynthc~is nf starch from carbon dioxide and light in plant life. It apparently has the propert.v of stimulating rell metabolism the phpsiologic healing of injured and has been found useful in I)romoting tissue. It also seems to have an antibacterial action but in t,est tube experiments this ability is not outstanding. Its action against microorganisms is due principally to its effect on the tissues of the host rather than directly on the bacteria thenwclvt*s. This act.ion might raise some doubt as to its specific usefulness in c.aries control. However, preliminary studies in which chlorophyll was fed in the drinking water in a l-500 dilution to Syrian hamsters on a caries-producing Male diet demonstrated a marked reduction of caries in the female sex.” animals who received this anti-caries treatment apparently did not show similar improvement. I am not yet, aware of an explanation for this sex linkage. X I)reliminary rel)ort has been made on the effect of chlorophyll on oral lactobacilli counts.ls A dramatic reduction in oral lactobacilli was secured through the use of chlorophyll tooth paste. The paste known as “ Chloresium” was used twice a day, one of the times being after breakfast,. Within ten days from the time the chlorophyll therapy was begrut 26 per cent of the subjects had neyative lactobacilli counts. After a twenty-six week period, 90 per cent of the fifty stthjccts using the . . ( Ihloresium’ ’ were free of lactobacilli. Subsequent caheckslty other in\-esti,qators have not ol)served c~omparable reductions, perhaps t)rca\lstfi the mailner of I)ruAing was not esactl), duplicated. I nnclerstand t.hat a large scale clinical study is to be started soon to deterrniup t lte &%~tiveness of ‘. C’hloresium ’ ’ tooth paste in caries reduction uncle1 c&olLtrolled conditions and (~onclnsions should not be made about it until this study is cdompleted. There have been accompanyin g reports of improvements in soft tiss;nt conditions al)out the oral cavit?- t.hrough the apI)lication of chlorophyll ;Intl likewisr on the ?&uction of tnollth odors Following its use. These features 401\1~1 enliiinre tlic use of this agent in c*WriW Pant rol if clinical studies prove it Jfec+vc.
448
ROBERT
Flnoritle
G. KESEL
for the I~rerention 01 clental caries also ~OIUO under this this f(Jl’Il1 ha\-e little contact with the dental enamel and there is no good evidence that the fluoride content. of the enamel in the completed and erupted tooth can he incwawcl I,- fluoride ingestion. The use of fluoride tablets would seem to he entirely irrational. Synthetic vitamin I<. more properly known as menadionr, a,nd &eerie aldeh,vtle hare Iwen snpgcstrtl and studied for the possibilities they might offer as varies inhibitors. The;. arc’ c:nxyne ;)oi,on, and t.hrir rationale is to reduce or inhihit fermentation I,>- 1*enclerinF thr rtywnsihle cnzymcs inactive. It is hoped that they min.ht he coml~inctl \vith the fcrmentahle earhohydrates so that the consumption (Jf the latter \\-oultl not result in rapid ad production ill the oral cavity. The rationale is escellent, l)lit the possibility of toxicity through the continuous inzrstion of swh material ovel a periocl of J’ears has not been ruled out. In a test on IalwratorJ- animals, Klyceric al~lcll~-de in a caries-producing diet dicl not ])rove to he an effective caries deterent.“’ In summary, there is good evidence that we have three established means for caries wntrol : (I ) redwins the consumption of refined carbohydrates, (2) cleansing the mouth immccliatel?- after eating, (3) the topical application of a 2 per cent sodium fluoritlc solution to the clean, (lry tooth surface. There are other I)romising methotls. hut further study is necessary to make their effects more convincing.
wtey’ory.
tablets
F’lIIorides
in
References 1. 5. 3. 4. 5. 6. i. 9: 10. 11. 1”. 13. 14. 15. 16. 17. 18. 19. 20 21:
D. A. 26: 59-70, 1950. Sugar anI1 Dental Caries : Panel Discussion, J. Cdifornia Dgkes. E T.: Continuing Pr~~blem IIf Srwrts. J. Cnlifornia D. A. 26: 2-2, 1950. Fosdick, L. S.: J. -Lru. Dent. A. 40: I?:;, 19.X. Personal rommnnication. Besic, F. C.: J. D. Rei;. 28: 279. 1949. ht. D. B.. Finn, R. B., and 3ZcC’:1ffrcy, I. : .11x .T. Pal). Health 40: 716? 19.31). Hill, I. N.. Blapncy. J. R., and TVolf, 1Vdter: 5. D. Rez. 29: 5:%, 1950. Dannenbew. .J. L.. and Bihbr. B. CT.: .T. D. Res. 29: iii’, 1950. Engle, M. “’ J. Am. Den. A.” i0: ?S-4, 1959. ORAL SIJRC., OR.\L MED.. .IND ORAL PATH. 3: 6SS, 1950. Drelzen, P., and Spies; T. D.: Reseawh, .r. Am. Dent. A. 41: 94, 1950. McClure, F. 5.. and Hewitt, TV. I;.: .T. D. RCA 25: 441, 1946. Zandcr, H. A., and Ribby, R. G.: J. D. Res. 26: 365, 1947. Hill. T. J., nncl Rneisner. A. H.: J. D. Res. 28: 263. 1948. Zander, H: A.: J. Am. bent. A. 40: 569, 1950. ’ Fitzgerald, R. J., Znnder, H. A., xntl Jordnn, H. V.: J. Am. Dent. h. 41: 67, 19.50. Hein, J. 1V.. xnd Shxfer, W. G.: Pennsylrania State D. J., rol. 26, June, 1919. R.app, G. It’., 2nd Gurney, B. F.: Unpnblid~ed. Reported International .4ssor. D. Res.! Chicago. June !WS~, 1940. Kneisner, -1. II., Mann. -1. W., anal Spies, ‘I’. D.: J. D. Rex. 21: 259, 194’7. Mann, 1. IV., Dreizen, 6.. Spie*, ‘I’. D., and IIu~lt, F. XI.: J. Am. Dent. A. 34: 244, 1947. Sham, James 1-I.: J. I). Res. 29: 2:. 1950.
OF RECENT DEVELOPMENTS
IN CARIES CONTROL
ESEARCH reported in the past two ~-cars 1~~ im1)rovta(l 011~untlerstanding It has given adtliof the effectiveness of srvrral varies wntrol I)rwedurcs. tional support to some’ illlY~It1~~ acwptct-1 iucthotls and has ~~lawtl in the (laestionable rategor!, some of t tie more rrt:entl~- advanvetl theories. I have attempted to classify the methods that have been given major al tent ion into three groups : first, those for which suffkient eritlence has acwmulated to indicate that the) are acceptable procedures: seconcly those for whirl1 there is evidence for their usefulness, but for which further research is necessary ; and, third. those methods which past experience and research hare labeled unacceptable. The classification is based on my analysis of published data and with the realization that personal I have arranged the evaluation in Table I for appraisal is subject to error. I have outlined clarity? to stimulate diwnssion, and for correction. if wrong. some of t.lie advantages and disadvantages of each provedwe. The most effect,ive way of controlling dental caries, in my opinion, is through eonwientious reduction in sugar eonsuml)tioii. Evidcnw has continued to atht*umutate to indict sugar as a major c.IllI)rit it1 tltr ~~rodwtit~~~ of wvities. Studies ~vII human beings, 011 t.aries-s;usc.t~l)t,il)le animak :lS Well its 1~l\NJlatO~‘\~ t’\ideIWc. sl~o\v ttir inipt)rtani relationstliI) twtxwll sllgr WJIlSllIll~~ti~Jli iln(l t*ilriW prodlit’1ion. between sugar elimination anti earics wstriction.
R
440
ROBERT G. KESEL
about the role of carbohydrates and acidogenic bacteria in caries production. The work in being done in collaboration between Notre Dame University and the Zoller Dental Clinic of the Universit.y of C’hicago. L4 method has been developed for delivering and raising rats in a bacteriafree environment. It has progressed to the point where the bacteria-free rats have been fed a diet that produces a high incidence of dental caries in the control animals. Personal communication with the workers tells us that no caries develops in the bacteria-free animals on this diet. St,udies are now underway in which the food supplied the sterile animals is contaminated with a pure strain of an acidogenic organism. one of the lactobacilli obtained from the oral cavity of an individual highly susceptible to caries. The purpose of this procedure, of course, is to determine the possibility of producing caries by the interaction of the diet and the single bacterial species in the rat mouth under these strictly controlled conditions. I believe this study, while slow and difficult, will make a most important contribution to our understanding of the caries etiology. TABLE
I.
CARIES I
I ! *L. Reduce
c'0r;rp.o~ ADVANTAGES
sugar-’ intake a.7== (especially b e t m e e n b. Improved meals)
and,'or Brush teeth rinse mouth immediately after eating
Topical
of mater 7C~tluction b. Mass control
2. hmmoniate~l
dentifrice,
Tooth impregnation a. Zinc chloride b. Silver nitrate Penicillin
(8) method
a. Caries reduction ( 8) b. Use of (‘natural” antibiotic
tlentifrice
Caries
re:luction
Caries
retluction
1. Calciumtherapy
1.
2. Vitamin
therapy
2.
Fluoride
tablets
4. Synthetic 5. Glyceric
Vitamin aldehyde
Because K
J
3. 4. 5.
Mass cooperation ficult b. Economy a. Inconvenience discipline b. Rigid quired
a. Caries reduction (8) cooperation 1). Patient unnecessary
dentifrice
I.a. Chlorophyll I
__IUNA%c~i3~~~~t3.
a. Caries reduction 1,. Clean mouth
application of a. Caries reduction fluoride b. Simplicity
Fluoridation
DISADVANTAOES
I
-/a. nutrition
(8)
dif-
re.
a. Not a mass control method dental ap,h. Requires . . pomtments Not yet proved / Rigid
discipline
required
a. Causticity b. Discoloration c. Time consuming a. Sensitization b. Drug fastness required c. Discipline
Rigid discipline required C? not related to calcium metabolism Caries is a dietary, not nutritional disease Not absorbed by completed enamel Toxicity Toxicity (8)
A distinct advantage in reducing sugar consumption is not only the possibility of reclucing caries activity but also of improving nutrition. The sugar used in 1~11ms1n cn!!qll.mption provides only calories and no other nutrient and in addi-
RECENT
DEVELOPJIENTS
IS
(‘ARIES
CONTROL
441
tion it is a great appetite appeaser. I was startled by a report published during the past )-ear by Dr. E. Taylor I)ykes.2 Ht: reported a survey that was made bp questionnaire of 23!000 school children in Oakland, Calif. It re\.ealed the follow ing : IS.8 per cent had candy before 9 a.m. 35.1 per cent had candy before 1 p.m. 6.1 per cent had soft drinks before 9 a.m. 15.3 per writ had soft drinks before I p.m. Fifty-four per cent of ( )aklancl school ehilclwn habitually- consumed can+ or soft drink before 1 p.m. and thesr were prohahly the children with a lo\\ total of basic physiologically required calories. The repla.cement of refined sugar calories with foods of substance will benefit nutrition as a whole. However, a realistic disadvantage to the control of dental caries by this desirable method is an uiicontrollable psyAiological one. sugar is sweet and sweetness always has a good connotation. The public appears to have greater regard for its sweet tooth than for its own natural teeth. Until there is developed a new psychological approach different from any now available, the large wale control of caries activity through sugar reduction is wishful thinking. For individuals yes; for the masses, no. Another obvious and serious clisaclranta,ge to this means is the economy They are, ot’ L’OLWS~, much less expensive provided by the use of carbohydrates. than the foocls that should be substittttetl in order to provide better nourishment along with caries reduction. It appears that sugar is here to sta).. and that we must. learn to live with it with iml)rovecl clental health.
During the first year of Dr. Fosdick’s stnd>-. the 526 test subjects showed il 1J.31.E’. recluc&tioti of 63 lwr w11t ~~~n~~~awcln-itti thcj IYI~I~rol group containing 306 subjects. The study was continuc,d a second year but the contrast between the test. and control groups xl-as not nearly as treat during the second-year ljeriod. During the second year the test sllh,jects hacl a reduction of 26 per cent
over the controls. The difYerrnce was not due to any lack of improvement in the test subjects, but rather to the fact that the controls showed a decided improvement in their caries experiellpe during the second year. It is suggested t.hat a pla~Gl)le reason Tar this improvement anlong the controls Iv-as an awareness that. they developecl of the value of oral h>-gienc performed soon after eating. So much publicity has been given to this procedure through various channels that individuals of college age might. be expected to change voluntarily their hygiene procedures. The results reported 1,. Dr. Fosdick have statistical significance and are the first controlled studies reporteti to justify the use of the toothbrush as a weapon against tooth decay. An advantage of this procedure in addition to caries control is the maintenance of a clean mouth. This feature should have a beneficial effect on other oral conditions and should provide an impetus for better mouth health. The disadvantages of this procedure, of course, are its inconvenience ancl the rather rigid discipline that it requires. Toothbrushing immediately after eating cannot be considered a conyeuient routine. Therefore, the discipline that would be requirecl to recluce caries incidence in large numbers of individuals will be difficult to obtain. There is suggestive evidence in Dr. Fosdick’s report that, rinsing the mouth vigorously with water immediately after eating fermentable material reduces the incidence of caries. He cited one college where the drinking fountain was close to the cand)- counter and less caries was obserrecl in this group who presumably- fotund it more convenient to rinse The possibilit,ies of flushing the mouth the mout.h after the sugar consumption. with water or with an antiseptic solution should be furt.her explored as such a procedure could be more easily aclopted than the habitual use of the toothbrush after eating. A third procedure for reducing ca.ries actirit>- that has receivecl general acceptance is the topical application of a 2 per cent sodium fluoride solution to the clean, dry tooth surface. Much evidence has accumulated through a number of studies by different, investigators indicating a caries reduct,ion of approxiXn adva.ntage of this method is mately 40 per cent t~hrough this procedure. A study recently made by the Illinois State Health its apparent simplicity. Department suggests t.hat the rather superficial prophylaxis that has usually preceded the topical application can be eliminated if the incliviclual will brush his teeth well for at least two weeks prior to the a.pplication. This stucly done on school children in Edwards County, Ill., indicates that the youngsters who brushed their teeth in the classroom twice each day over a two-week period prior to the application of the fluroide solution showed a reduction in caries at t,he encl of one year comparable to that observed in the group that, was given a prophylaxis by a clental hygienist. An earlier stud) had indicated that the topical application of fluorides to teeth that had not had a prophylaxis secured only half the protection. The reported fluorine studies do not indicate whether this preventive treatment is more effect.ive in controlling certain types of cavities than it is fol others. It. would be interesting to know whether or not the surfaces that are easily contacted with the fluoride solution are t,he ones that secure the greatest protect,ion.
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A study reported about a J-ear ago indicates that the areas of contact 01’ close approximation arc t.he ones least likely to be contacted by the topical application of a solution” The investigator, Dr. Kesic, tlemonstrated that ions or molecules of a solution diffuse with difficultp into the areas of contact between sl)herical solid bodies, be they teeth or steel balls? when they are immersed in a licluid. Al suggested reason for this lack of diffusion is a thinning out of the snllltiolr ill the area of wntact, resulting ilk a redwtion in the wncentration of ions in that area. IIis observations suggest that the nar~~\v pits, fissures, and the areas close to the contact point should be least protected by the tiuoride solution. Special effort would have to be made to contact these most, susceptible ;treas if the masimum protection is to be secured. This method, of course, requires dental al)pointments and the time of trained personnel which complicates its usefulness as a mass control method. The simplest methocl yet sugge&ed for reducing caries activity is the fluoridation of drinking water. According to the surveys made by the United Stat,es Public Health Service and others, children residing in areas where the drinking water contains approsiniately one part, per million of fluorides have about a 60 per cent lower caries experience rate. About six times as man\- children in these communities show no dental caries espcrience as do those in areas where the drinking water is fluoride free, and there is a decrease of i5 per cent in the loss of first permanent molars. A nnmber of studies hare been set 111)to determine whether or not the art,ificial fluoridation of the water supply in the test communities will obtain the same caries protective benefit without increasing an!- tosic manifestations. Hcwntl~~ :I rcpurt on one of the water fluoridation stntlics was published qi\.ing results observed during the first tlircc years.” The towls involwd in this rqvriment are IVcwl)urg and Kingston, 1cI. \-.. ( hi Ala?, 2. 194.5, the Newburg water supply had its flnorinc ~*Olltellt hrtbqkt ‘11’ tu 1.0-l .? p:irts 1JCr IIdliOll. The Kingston water snppl?- \vas left tlnorine ircra. Thvrc :I I’C al)l)roxirnatel~ :3,400 children under stud\- in Newlmrg and ?.S(JO c.tiildwn iii KingSton. ‘She clental rtsaniinations wcw rnatle with the aitl of !t)oLttli Illirrt)rs and sharp esplorers.
44-I
ROBERT
(:.
KESEI.
the approval of the state and local health authorities and the dental and medical professions. This recommeiiclatiotI has the npproral of the Unit,ed States Public Health Scr\+e for use where the community can meet and maintain the standards required b\, thr state health authority-. .I rewnt report has lwen made ol’ tlrth fifteewycar tluoridation study that. is under ~a?- in E’:anston. Ill., binder the direction of I)r. .J. R. Blayey.’ The examinations reported were made in the post-fluoride period from observations on 6- to S-)-ear-old children. These children showed an increase in the caries rate for the deciduous teeth during the post-fluoride period. However, statistical analysis indicated a marked reduction in the caries preralence in their permanent. teet.h. While the assumption wulcl he made that the sodium fluoride had greater effect on the permanent teeth than on the deciduous teeth because t.he permanent teeth had been exposed to the fluoride water for almost theil posterupt,ive life, Dr. Blayney felt that the trend is as he stated “far from conclusive. It cannot be assumed at this early time, and cannot be contributed to chance, that the changes that, hare taken place are necessarily clue to the addition of sodium fluoride. ’ ’ Dr. Blayney’s attit,ude is conservative, but 1)erhaps rightly so in riew of the fact that most all of those who are studying this phase of caries control agree that the long term studies under w-a>- should be concluded before final decisions can be clrawn. The use of ammoniated dentifrices l’or caries control has been considered in the previous paper. Another method for caries control that. has been widely used in the last few years is the so-callecl tooth impregnation technique advocated originally by Dr. Gottlieb. The rationale for this procedure as reported by its investigators is based on a different concept of caries etiology than the one more widely held which is based on the belief that the predominant destructive factor in cavit> production is the dissolution of the hard tooth ti.jsue b)- acid. The theory behind the tooth impregnation procedure is that t.he orp; lnic components of the teeth are initially at,tackecl by the carious process and provide inroads into the tooth A 20 per cent solution of pot.assium ferrocyanide tissue for bacterial invasion. is used to precipitate a 10 per cent solution of zinc chloride previously applied It is believed by the proponents of this techto the clean, dry tooth surface. nique that the organic st,ructures are so occluded by this impregnation with the zinc iron salt that bacteria can no longer enter them and that these organic structures are rendered less susrcptible to proteolysis. A check on the effectiveness of zinc chloride and potassium ferrocyanide in influencing the proteolysis of organic material has been reported during the past year.8 Coagulated egg albumin was exposed to the action of zinc chloride and potassium ferrocyanide and then to the action of the proteol-tic enzyme trypsin. It. a.ppeared from these studies that the zinc chloride-Ijotassium ferrocyanide enhanced the proteolysis rather than hindered it. Dentine specimens of extracted teet.1~were given an impregnation treatment and then were subjected to bhe action of trypsin. Normal dentine was not affected by tr,vpsin, but when
KEC‘EST
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446
ROBERT
G. KESEL
Their disadvantages are that the: do rccluire the time and skill of tra,ined personnel for their application. Then, too, the)- are caustic and silver nit&e can produce a marked discoloration in the tooth tissue. It. was only logical followin g reported observations on the striking effect of pcnieillin on the oral bacterial flora to tind penicillin advocated as a cariesreducing agent. Preliminary studies done on laboratory animals showed t.hat when penicillin was contained in the drinking water or when the animals’ teeth were brushed with a penicillin-containin, w dentifrice, a reduct.ion in caries esperience was obtained.l’, I’: Early reports also indicated that when a penicillin dentifrice or mouthwash was used in the human oral cavity a reduction occurred in salivary lact,obacilli counts. IIowevert a study conducted on orphanage children using a penicillin dentifrice under unsupervised conditions produced no caries reductionl” A more recent report deals with 409 children who brushed their teeth under supervised conditions in the school classroom.‘” Two hundred thirty-fire ehildren brushed with a tooth powder containin g fiCI0 units of potassium penicillin per gram, 174 with a similar powder lacking in penicillin. The children brushed once daily in the school room and were instructed to brush at home morning and evening. The results of the study show an approximate decrease of 50 per cent in caries activity of those children who used the penicillin powder. These results indicate that the effect of the penicillin was significant. The problem of penicillin sensitivity- arises but according to the above report a minor amount of sensitivity was observed. Only t,wo children were dropped from the program because of what appeared to be an allergy to one or more ingredients of the tooth powder. Further studies were conducted on inmates of penal inst.itut,ions and private patients who used the penicillin dentifrice for three months. Twenty-eight or only 0.65 per cent showed manifestations similar to t.hose observed in the school study and the same conclusions were drawn, name1.v. that the majority of these manifestations were not related to the penicillin but were produced hy some other ingredient in the dentifrice. The usual estimate of the number of people sensitive to penicillin in the population is about 8 to 10 per cent, but, this percentage of reactions was in no way observed in this study. The usual manifestations of penicillin sensitivity through oral contact are soreness of the throat, and tongue, dryness of the lips, burning sensations t.hroughout the mouth, some impairment of taste, the development of esfoliatire lesions or fissures at the labial commissures. The rationale of penicillin t,herapy for caries control originally was predicated on its influence on the bacterial flora of the mouth. Contrary results were obtained in this stuciy.l” Despite the 50 per rent. reduction in clinical caries activity, there was no significant change in lactobaeilli counts. It. might be assumed that. this result WIY due to the development of penicillin-resistant lactobacilli. However, in some carefully done bacterial studies, it was found that there was no increase in the number of penicillin-resistant lactobacilli in the mouths of the children using the 1)enicillin dentifrice. It would seem that there must be some other explanation for the failure of the lactobacilli counts to eointide with the reduced caries activity.
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The results to date indicate that penicillin may prove to be a useful means of combating tooth decay. However, the possibility of penicillin sensitivity and the production of penicillin-resistant organisms of the pathogenic variety other than lactobacilli must he carefully studied. Another antibiotic that may prove beneficial to oral health including reduced caries activity is ~~l~lo~~oI~l~~-ll.Vhlomphyll is the catalytic agent that I am sure .~.ou know brings al)out the photosynthc~is nf starch from carbon dioxide and light in plant life. It apparently has the propert.v of stimulating rell metabolism the phpsiologic healing of injured and has been found useful in I)romoting tissue. It also seems to have an antibacterial action but in t,est tube experiments this ability is not outstanding. Its action against microorganisms is due principally to its effect on the tissues of the host rather than directly on the bacteria thenwclvt*s. This act.ion might raise some doubt as to its specific usefulness in c.aries control. However, preliminary studies in which chlorophyll was fed in the drinking water in a l-500 dilution to Syrian hamsters on a caries-producing Male diet demonstrated a marked reduction of caries in the female sex.” animals who received this anti-caries treatment apparently did not show similar improvement. I am not yet, aware of an explanation for this sex linkage. X I)reliminary rel)ort has been made on the effect of chlorophyll on oral lactobacilli counts.ls A dramatic reduction in oral lactobacilli was secured through the use of chlorophyll tooth paste. The paste known as “ Chloresium” was used twice a day, one of the times being after breakfast,. Within ten days from the time the chlorophyll therapy was begrut 26 per cent of the subjects had neyative lactobacilli counts. After a twenty-six week period, 90 per cent of the fifty stthjccts using the . . ( Ihloresium’ ’ were free of lactobacilli. Subsequent caheckslty other in\-esti,qators have not ol)served c~omparable reductions, perhaps t)rca\lstfi the mailner of I)ruAing was not esactl), duplicated. I nnclerstand t.hat a large scale clinical study is to be started soon to deterrniup t lte &%~tiveness of ‘. C’hloresium ’ ’ tooth paste in caries reduction uncle1 c&olLtrolled conditions and (~onclnsions should not be made about it until this study is cdompleted. There have been accompanyin g reports of improvements in soft tiss;nt conditions al)out the oral cavit?- t.hrough the apI)lication of chlorophyll ;Intl likewisr on the ?&uction of tnollth odors Following its use. These features 401\1~1 enliiinre tlic use of this agent in c*WriW Pant rol if clinical studies prove it Jfec+vc.
448
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Flnoritle
G. KESEL
for the I~rerention 01 clental caries also ~OIUO under this this f(Jl’Il1 ha\-e little contact with the dental enamel and there is no good evidence that the fluoride content. of the enamel in the completed and erupted tooth can he incwawcl I,- fluoride ingestion. The use of fluoride tablets would seem to he entirely irrational. Synthetic vitamin I<. more properly known as menadionr, a,nd &eerie aldeh,vtle hare Iwen snpgcstrtl and studied for the possibilities they might offer as varies inhibitors. The;. arc’ c:nxyne ;)oi,on, and t.hrir rationale is to reduce or inhihit fermentation I,>- 1*enclerinF thr rtywnsihle cnzymcs inactive. It is hoped that they min.ht he coml~inctl \vith the fcrmentahle earhohydrates so that the consumption (Jf the latter \\-oultl not result in rapid ad production ill the oral cavity. The rationale is escellent, l)lit the possibility of toxicity through the continuous inzrstion of swh material ovel a periocl of J’ears has not been ruled out. In a test on IalwratorJ- animals, Klyceric al~lcll~-de in a caries-producing diet dicl not ])rove to he an effective caries deterent.“’ In summary, there is good evidence that we have three established means for caries wntrol : (I ) redwins the consumption of refined carbohydrates, (2) cleansing the mouth immccliatel?- after eating, (3) the topical application of a 2 per cent sodium fluoritlc solution to the clean, (lry tooth surface. There are other I)romising methotls. hut further study is necessary to make their effects more convincing.
wtey’ory.
tablets
F’lIIorides
in
References 1. 5. 3. 4. 5. 6. i. 9: 10. 11. 1”. 13. 14. 15. 16. 17. 18. 19. 20 21:
D. A. 26: 59-70, 1950. Sugar anI1 Dental Caries : Panel Discussion, J. Cdifornia Dgkes. E T.: Continuing Pr~~blem IIf Srwrts. J. Cnlifornia D. A. 26: 2-2, 1950. Fosdick, L. S.: J. -Lru. Dent. A. 40: I?:;, 19.X. Personal rommnnication. Besic, F. C.: J. D. Rei;. 28: 279. 1949. ht. D. B.. Finn, R. B., and 3ZcC’:1ffrcy, I. : .11x .T. Pal). Health 40: 716? 19.31). Hill, I. N.. Blapncy. J. R., and TVolf, 1Vdter: 5. D. Rez. 29: 5:%, 1950. Dannenbew. .J. L.. and Bihbr. B. CT.: .T. D. Res. 29: iii’, 1950. Engle, M. “’ J. Am. Den. A.” i0: ?S-4, 1959. ORAL SIJRC., OR.\L MED.. .IND ORAL PATH. 3: 6SS, 1950. Drelzen, P., and Spies; T. D.: Reseawh, .r. Am. Dent. A. 41: 94, 1950. McClure, F. 5.. and Hewitt, TV. I;.: .T. D. RCA 25: 441, 1946. Zandcr, H. A., and Ribby, R. G.: J. D. Res. 26: 365, 1947. Hill. T. J., nncl Rneisner. A. H.: J. D. Res. 28: 263. 1948. Zander, H: A.: J. Am. bent. A. 40: 569, 1950. ’ Fitzgerald, R. J., Znnder, H. A., xntl Jordnn, H. V.: J. Am. Dent. h. 41: 67, 19.50. Hein, J. 1V.. xnd Shxfer, W. G.: Pennsylrania State D. J., rol. 26, June, 1919. R.app, G. It’., 2nd Gurney, B. F.: Unpnblid~ed. Reported International .4ssor. D. Res.! Chicago. June !WS~, 1940. Kneisner, -1. II., Mann. -1. W., anal Spies, ‘I’. D.: J. D. Rex. 21: 259, 194’7. Mann, 1. IV., Dreizen, 6.. Spie*, ‘I’. D., and IIu~lt, F. XI.: J. Am. Dent. A. 34: 244, 1947. Sham, James 1-I.: J. I). Res. 29: 2:. 1950.